EPA-744-R-93-001

DETERMINATION OF RATES OF REACTION IN THE GAS-PHASE IN THE TROPOSPHERE 

# THEORYANDPRACTICE

5. Rate of Indirect Photoreaction: Evaluation of the Atmospheric Oxidation Computer Program of Syracuse Research Corporation for Estimating the Second-Order Rate Constant for the Reaction of an Organic Chemical with Hydroxyl Radicals by Asa Leifer

U.S. ENVIRONMENTAL PROTECTION AGENCY OFFICE OF POLLUTION PREVENTION AND TOXICS WASHINGTON, DC 20460CONTENTS

Abstract 

# .. . . . . . . . .

# .. . . . .

# . . .. . . . xii I. Introduction • 

# . . . . . . . . . . . . . 1 II. Mathematical Synopsis of the Structure/Reactivity Relationships of Atkinson andMeylan . . . . . . 3 III. SyracuseResearch Corporation Atmospheric Oxidation Computer Program (Developed by Meylan) • • • • • • • • • • • . • • • • • • 14 III.A. III.B. IV.

IV.A.

IV.B.
IV.C. IV.C.l. IV.C.l.a. IV.C.l.b. IV.C.2. IV.C.2.a. IV.C.2.b. IV.C.3. IV.C.3.a. IV.C.3.b. Introduction • •

# . . .. . . . ... .. . . . . Atmospheric Oxidation Computer Program (AOP) Evaluation of the Atmospheric oxidation computer Program for Estimatingkoa and the ExperimentallyMeasured koa Data Listed in the Program
. • . . • • . . • comments on the Group Rate Constants, Substituent Factors, and Other Parameters Used by theAtmospheric Oxidation Program

# . . . .

. . . 14 15

29
29
some Comments onHydroxyl Radical Addition to Heteroaromatic and Fused Polyaromatic Ring systems • • • • . • • • • • . • • • . . • . . . 46 H-Atom Abstraction from c-H and -OH Groups by Hydroxyl Radicals 

# ....

# ........... 52 SaturatedAlkanes 

# ..

# ..

# ......... 52 Evaluation of the Experimental koa Data 52 Evaluation of the Estimatedkoa Data

# .... 57 Haloalkanes 

# .........

# ..... .

# .. . 59 Evaluation of the Experimental koa Data 

# .... 59 Evaluation of the Estimatedkoa Data 

# .

# ... 62 carbonyl Compounds

# ............. 62 Evaluation of the Experimental koa Data 62 Evaluation of the Estimatedkoa Data

# .... 68 iiIV.C.4. Alcohols, Glycols, Ethers, and Hydroperoxides 71 IV.C.4.a. Evaluation of the Experimental koH Data 71 IV.C.4.b. Evaluation of the Estimated koH Data

# .... 71 IV.C.5. Alkyl Nitrates and Nitriles 

# ...

# . 79 rv.c.s.a. Evaluation of the Experimental koH Data 

# .... 79 IV.C.5.b. Evaluation of the Estimated koa Data

# .... 82 IV.C.6. Nitroalkanes

# .

# . .... •

# ..

# ... 

# ...

# . 82 IV.C.6.a. Evaluation of the Experimental koa Data 

# ...

# . 82 IV.C.6.b. Evaluation of the Estimated koa Data 

# .... 85 IV.C.7. Alkyl Nitrites

# ..

# .......

# ....

# .... 87 IV.C.7.a. Evaluation of the Experimental koa Data 

# .... 87 IV.C.7.b. Evaluation of the Estimated koa Data

# ...... 88 IV.D. Addition of Hydroxyl Radicals to Alkenes, Conjugated Dialkenes, Alkynes, and 1,2-Dialkenes 

# ..

# ..

# .....

# ...

# ..... 89 IV.D.1. UnsubstitutedAlkenes 

# .

# ...

# ..... 89 IV.D.1.a. Evaluation of the Experimental koa Data 

# .... 89 IV.D.1.b. Evaluation of the EstimatedkoH Data 

# .... 93 IV.D.2. SubstitutedAlkenes 

# ............

# .. 94 IV.D.2.a. Evaluation of the Experimental koa Data 

# .... 94 IV.D.2.b. Evaluation of the Estimated koa Data

# . ... 97 IV.D.J. Conjugated Dienes 

# ..

# ..... .......

# . 97 IV.D.J.a Evaluation of the Experimental koa Data 

# . .

# .. 97 IV.D.J.b. Evaluation of the Estimated koH Data. 

# . .... 99 IV.D.4. Alkynes and 1,2-Dienes (Allenes) 

# . ..

# . 99 IV.D.4.a. Evaluation of the Experimental koH Data 99 IV.D.4.b. Evaluation of the Estimated koa Data 

# ..

# . 99 iiiIV.E.

IV.E.l. IV.E.l.a. IV.E.l.b. IV.E.2. IV.E.2.a. IV.E.2.b. Reaction of Hydroxyl Radicals with Organic Compounds Containing Sulfur, Nitrogen, and Phosphorous Functional Groups • • . • . • Reaction with Thiols, Sulfides, and Disulfides Evaluation of the Experimental koH Data 

# ... Evaluation of the EstimatedkoH Data

# ..

# .. . Reaction with Sulfoxides and Sulfates 

# .

# ... Evaluation of the Experimental koH Data 

# ... Evaluation of the EstimatedkoH Data 

# ..

# .. IV.E.J. Reaction withAlkyl Amines, Alkyl Hydrazines, . 101



# . 101



# . 101



# . 104



# . 105



# . 105



# . 105
and N-SubstitutedAmines • • . . . . . . 108 IV.E.J.a. Evaluation of the Experimental koH Data 108 IV.E.J.b. Evaluation of the EstimatedkoH Data
. . 108 IV.E.4. Reaction with Compounds Containing Phosphorous Functional Groups • . • . • . . . . . . . . 110 IV.E.4.a. Evaluation of the Experimental koH Data . 110 IV.E.4.b. Evaluation of the EstimatedkoH Data .••... 110 IV.F.
IV.F.l. IV.**F~**La. Reaction of Hydroxyl Radicals with Aromatic Compounds, Heterocyclic Aromatic Compounds, and Fused Ring Polyaromatic Compounds

. . • Aromatic Compounds • • • • • • 

# . . . . . . Evaluation of the Experimental koH Data IV.F.l.b. Evaluation of the Estimated Data •.•. IV.F.2. IV.F.2.a. IV.F.2.b. IV.F.3. IV.F.J.a. Heterocyclic Aromatic compounds Evaluation of the Experimental koH Data Evaluation of the EstimatedkoH Data
. . 

# .. .
Fused Ring Polyaromatic Compounds 

# .. . . Evaluation of the Experimental koH Data IV.F.J.b. Evaluation of the EstimatedkoH Data .•. iv 113

. 113

. 113 119

. 120

. 120

. 122

. 123

. 123

. 123IV.G.



## v. Evaluation of the Estimated Half-Life for the Reaction of Hydroxyl Radicals with Organic Chemicals in the Troposphere References • • . . . . •

# ..

# .. . .

# ..

v • 125
• • • • 127Table 1. Table 2. Table 3. Table 4. Table 5. Table 6. Table 7. Table 8. Table 9. Table 10. Table 11. Table 12. LIST OF TABLES Group Rate Constants for Hydrogen Abstraction and Radical Reaction

. • . • • . . . . . . 30 Substituent F(X} Factors for Hydrogen Abstraction • • • . . • . • . • . 

# .

# ... 31 Factors Used for Aliphatic Ring Strain Effects

. • . . . • • • . 

# . . .. 33 Group Rate Constants for OH Radical Addition to Isolated OlefinicUnits • • • • • • • • . • 34 Group Rate Constants for OH Radical Addition to Conjugated OlefinicUnits • • • • • • • • • 35 Group Rate Constants for OH Radical Addition to Alkyne Units • • • . . • . • • • • . . 37 Group Rate Constants for OH Radical Addition to 1,2-Dialkene (Allene} Units • • • . . • 38 Substituent Factors [C(X}] for OH Radical Addition to Olefins and Acetylenes • • • Electrophilic Substituent Factors for OH Radical Addition toAromaticRings • 

# . . .

. . . Experimental Values of Ai for Some Monocyclic Heteroaromatic Compounds 

# .. . .. Experimental Values of Bi for some Polynuclear Aromatic Compounds

. Values of Bi for Polynuclear Aromatic Hydrocarbon Structures Derived from ExperimentallyMeasured Ionization Potentials

. • • • • • • • • . • . • •

# . . . .

. . .. 39 40 47 48

49 Table 13. Values of Bi for Polynuclear Heteroaromatic Structures Derived from ExperimentallyMeasured Ionization Potentials • . • . . . . . . • 50 Table 14.A. Comparison of the EstimatedValues of koH at 298 Kfor saturated Acyclic Alkanes from the Atmospheric oxidation Computer Program (AOP} and from a Hand Calculation (HC} and the Experimental koa Data Reported in the Literature versus the Experimental koH Data Reported in AOP • • . . . . . . . . . . . 53 viTable 14.B.

Table 15.

Table 16. Comparison of the Estimated Values of koH at 298 K for Saturated Cyclic Alkanes from the Atmospheric Oxidation Computer Program (AOP) and from a Hand Calculation (HC) and the Experimental koH Data Reported in the Literature Versus the Experimental koH Data Reported inAOP • • • • • • • . • • . 

# . .

# .. . Comparison of the Estimated Values of koH at 298 Kfor Haloalkanes from the Atmospheric Oxidation Computer Program (AOP) and from a Hand Calculation (HC) and the Experimental koH Data Reported in the Literature Versus the Experimental koH Data inAOP • • • • • • • • • • • Comparison of the Estimated Values of koH at 298 K for Carbonyl Compounds from the Atmospheric Oxidation Computer Program (AOP) and from a Hand Calculation (HC) and the Experimental koH Data Reported in the Literature 

# .

# . . 55

60

Versus the Experimental koH Data in AOP • • • • • • • • • • • • • • . . • . . • . • 6 3 Table 17.

Table 18.

Table 19. Comparison of the EstimatedValues of koH at 298 Kfor Alcohols, Glycols, Ethers, and Hydroperoxides from the Atmospheric Oxidation Computer Program (AOP) and from a Hand Calculation (HC) and the Experimental koH Data Reported in the Literature Versus the Experimental koH Data inAOP

. • • • • Comparison of the Estimated Values of koH at 298 Kfor Alkyl Nitrates and Alkyl Nitriles from the Atmospheric Oxidation Computer Program (AOP) and from a Hand Calculation (HC) and the Experimental koH Data Reported in the Literature Versus the Experimental 

# . . . .

koH Data inAOP

. • • • • . • • • • •

# .. .

# .. Comparison of the Estimated Values of koH at 298 K for Nitroalkanes and Alkyl Nitrites from theAtmospheric Oxidation Computer Program (AOP) and from a Hand Calculation (HC) and the Experimental koH Data Reported in the Literature Versus the ExperimentkoH Data inAOP

. . • . . • . . • • . vii 

# .

# . .. . 72

80

83Table 20.

Table 21.

Table 22.

Table 23.

Table 24. Comparison of the EstimatedValues of koH at 298 Kfor Unsubstituted Alkenes from the Atmospheric Oxidation Computer Program (AOP) and from a Hand Calculation (HC) and the Experimental koH Data Reported in the Literature Versus the Experimental koH Data in AOP

. . • . •

# . ..

# ..

# ..

# ..

# ..

# ...

# ... 90 Comparison of the EstimatedValues of koH at 298 Kfor SubstitutedAlkenes from the Atmospheric oxidation computer Program (AOP) and From a Hand Calculation (HC) and the Experimental koH Data Reported inthe Literature versus the Experimental koH Data in AOP • • • • • • • • • • • • • • • • . • • • . . 9 5 comparison of the EstimatedValues of koH at 298 Kfor conjugatedAcyclic and Cyclic Dialkenes from the Atmospheric oxidation Computer Program (AOP) and from a Hand Calculation (HC) and the Experimental koH Data Reported inthe LiteratureVersus the Experimental koH Data inAOP • • • • • • • • • • • • • • Comparison of the EstimatedValues of kQH at 298 Kfor Alkynes and 1,2- D1alkenes (Allenes) from the Atmospheric Oxidation Computer Program (AOP) and from a Hand Calculation (HC) 

# .. . . 98

and the Experimental koH Data Reported in the LiteratureVersus the Experimental koH Data inAOP.

. • . • • • • . • 100 Comparison of the EstimatedValues of koH at 298 Kfor Alkyl Thiols, Sulfides, and Disulfides from the Atmospheric oxidation computer Program (AOP) and from a Hand Calculation (HC) and the Experimental koH Data Reported in the LiteratureVersus the Experimental koH Data inAOP

. . . . . . . . . 102

viiiTable 25.

Table 26.

Table 27.

Table 28.

Table 29. Comparison of Estimated Values of koH at 298 K for Alkyl Sulfoxides and Sulfates from the Atmospheric Oxidation Computer Program (AOP) and from a Hand Calculation (HC) and the Experimental koH Data Reported in the Literature Versus the Experimental koH Data in AOP • • • • . • • • • • • • • • • • . . • • . . 106 Comparison of the Estimated Values of koH at 298 K for Alkyl Amines, Hydrazines, and N-Substituted Amines from the Atmospheric Oxidation Computer Program (AOP) and from a Hand Calculation (HC) and the Experimental koH Data Reported in the Literature Versus the Experimental koH Data in AOP • • • • • • • . • • • • • • • . • . • . . . 109 Comparison of the Estimated Values of koH at 298 Kfor Aliphatic Compounds Containing Phosphorous Functional Groups from the Atmospheric Oxidation Program (AOP) and from a Hand Calculation (HC) and the Experimental koH Data Reported in the Literature Versus the Experimental koH Data in AOP • . • • • . . . • . . • . . . . . • . . . . 111 Comparison of the Estimated Values of koH at 298 K for Aromatic Compounds from the Atmospheric Oxidation Program (AOP) and from a Hand Calculation (HC) and the Experimental koH Data Reported in the Literature Versus the Experimental koH Data in AOP • • • • • • • • • • • • • • . . . 

# . . . . 114 Comparison of the Estimated Values of koH at 298 K for HeterocyclicAromatic Compounds from the Atmospheric Oxidation Program (AOP) and from a Hand Calculation (HC) and the Experimental koH Data Reported in the Literature Versus the Experimental koH Data in AOP •••••••....•.......... 121

ix!

# ·.

Table 30. Comparison of the EstimatedValues of 

### koa at 298 Kfor Fused Ring Polyaromatic Compounds (PAH) from the Atmospheric Oxidation Program (AOP) and from a Hand Calculation (HC) and the Experimental

### koa Data Reported in the LiteratureVersus the Experimental

### koa Data inAOP • • • • • • • • • • . • . • • • . . 124

XFigure 1. Figure 2.

Figure 3.

Figure 4.

Figure 5. LIST OF FIGURES Atmospheric Oxidation Program Data Entry Display • • • • • . • • • •

# ..

# .. . Atmospheric Oxidation Program Data Display for the Compound a-Methyl Styrene {2-Phenyl- 1-Propene): summary Hydroxyl Radical Data and Experimental Data. A. Screen Displaywhen Key PgDn is pressed. B. Screen Displaywhen Key F-10 is pressed. Atmospheric Oxidation Program Data Display for the Compound a-Methyl Styrene {2-Phenyl- 1-Propene): Summary Hydroxyl Radical and Ozone Data. A. Screen Display when Key PgDn is pressed. B. Screen Displaywhen Key F-10 is pressed. Atmospheric Oxidation Program Data Display for the Compound a-Methyl Styrene {2-Phenyl- 1-Propene): A. Screen Display of the Detailed Calculations for Hydrogen Abstraction. B. Screen Display of the Detailed Calculations for OH Radical Addition to the Olefinic Bond.

. . . . . . . . . . . . . . . . . 

# .

# .. . .

# ..
Atmospheric Oxidation Program Data Display for the Compound a-Methyl Styrene {2-Phenyl- 1-Propene): A. Screen Display of the Detailed Calculations with

### o3 Reaction with the Olefinic Bond. • • • • • • • • • • . . . . 16

18 19

22 23

24
25

26 B. Screen Display of the Detailed Calculations of OH Radical Addition to the Aromatic Ring. • • • • • • . • • • . • • 27 Figure 6. Atmospheric Oxidation Program Data Display for the Compound a-Methyl Styrene {2-Phenyl- 1-Propene): Screen Display for OH Addition to the Aromatic Ring and the Experimental Data.
. . 28

xi 

# .·

## ·.

Abstract Atkinson (of the University of California at Riverside), in support of the research programs of the ExposureAssessment Branch, Office of PollutionPrevention andToxics, 

## u.s. Environmental ProtectionAgency, developed structure/reactivity relationships (S/R) for estimatingthe second-order rate constant for the reaction of hydroxyl radicals with organic chemicals in the gas-phase inthe troposphere (koa>· Meylan, of Syracuse Research Corporation, computerizedthese S/Rrelationships and, in addition, developed S/Rrelationships for a few other classes of organic chemicals. This computer program is calledthe Atmospheric OxidationProgram (AOP) 1• Furthermore, at the request of Leifer, Meylan incorporated a data base of the experimental values of koa for a large number of organic chemicals inAOP2• This computer program is operatedby inserting in itthe SMILES notation for a givenmolecular structure. This SMILES notation is a machine-readable code for themolecular structure of an organic chemical. AOP then estimatesk08, lists an experimental value (if available from the scientific literature),

1 This computer program also contains S/Rrelationships of Atkinson for estimatingthe second-order rate constant for the reaction of organic chemicals with ozone (ko ) in the gasphase inthe troposphere. This report,



### howe~er, will only reviewthe hydroxyl radical portion of this computer program.
2 AOP also lists the experimental values of k03, if available; and also lists the experimental values of kNOJ for the reaction of an organic chemical with nitrate radicals (N03), if available.
xiigives a detailed description of the calculations, and estimates the half-life in the troposphere for this chemical. This computerprogramwas thoroughly evaluated by comparing the estimated and experimental values of koH from AOP with the hand calculated and experimental values of Leifer for 454 organic compounds covering a wide variety of classes of compounds. These koa data are listed in Tables 14-30. When comparingthe estimated values of koH byAOP and those by Leifer in a hand calculation (HC), a few comments can be made about the number of significant figures used. In general, the summary table inAOP lists k(i) and koH (the rate constant corresponding to each individual reaction pathway i and the total hydroxyl radical rate constantk0H, respectively) with up to a maximum of six significant figures. However, the group rate constants (e.g.,



### k~, **k~, k~,**  **k~s,**
**k~**

**,** k(>N-), k(-SH), etc.) and the substituent factors F(i) and C(i) [e.g., F(-CH2-), F(-Cl), F(>N-H), F(for strained rings containing n atoms), C(-F), C(=O), C(-C•N), etc.] are known, at best, to three significant figures and, in general, to two significant figures. Therefore, it is recommended thatAOP show the detailed calculations to four significant figures and listk(la), k(lc), k(>N-), kadd,nar' kadd,ar, etc. andkoH in the summary table with three significant figures. In general, after evaluating all 454 chemicals covering a wide range of chemical classes, itwas found that there was excellent agreement between the estimated values of koH and HC. xiii

# ·- Furthermore, the S/Rrelationships of Meylan for fused ring polyaromatichydrocarbons are superior to those of Atkinson. In addition, Meylan's S/Rrelationships have been expanded to cover heterocyclic aromatic compounds such as the thiazoles, oxazoles, pyridines, furans, etc. whereas Atkinson does not have corresponding S/Rrelationships. However, itmust be emphasized that considerablymore experimental koH data are needed for a number of substitutedheterocyclic and fused ring polynuclear aromatic hydrocarbons to verify the S/Rrelationships of Meylan. There are, however, some differences betweenthe estimatedvalues of koH from AOP and HC for a few classes of compounds which will be described in the following paragraphs. For the alkyl sulfides (both acyclic and cyclic), a comparison of the estimatedvalues of koH from AOP and HC indicates thatkoH is larger from AOP. The reason for this discrepancy is thatkoH was measured in the absence of oxygen and from Atkinson's S/Rrelationships, k(-S-) = 

### o so that onlyH-atom abstraction is observed. However, AOP estimateskoH by assuming thatk(-S-) = 2.0 and not

### o. Hence, when estimatingkoH for these compounds it is necessary to specifywhether the estimation ismade under the boundary condition of the presence or absence of oxygen. Therefore, it is recommended that AOP should be modified to take into account this boundary condition. For the aromatic compounds 3,5-dimethyl phenol, N,Ndimethylaniline, and 2,4-toluenediamine, AOP lists the maximum value for OH addition to an aromatic ring as 200 x 10-12 xivcm3molecule-ls-l (i.e., k(7) = kadd,arl

**wher~~**HC lists a Since the maximum allowed collision rate 

### is 200 x lo-12cm3molecule-ls-1 [Atkinson (1987)], this boundary condition must be invoked on the estimation of koa and not on k(7)[=kadd,arl· Furthermore, by using this boundary condition, the estimated values of koa for the above mentioned aromatic compounds aremuch closerto the experimental values (See Table 28 of this report and Leifer (1992a)). It should be noted that this comment 

### is only applicable to aromatic compounds and not to all compounds. For the compounds tetralin, indan, fluorene, and 2,3-dihydrobenzofuran, AOP makes a slight error in estimating the rate constant for the addition of OH radicals to the aromatic ring [i.e., k(7) = kadd,arl· For these compounds, AOP uses the incorrect value of a:(-CH2-) = 0.06 

### ** instead of the correct value of 0.064 

### **· Furthermore, the compounds tetralin, indan, and fluorene contain five membered strainedrings. In calculatingk(lc) for these compounds, AOP makes an error by omittingthe ring strain factor F(5) 

## =0.80. Thus, k(lc) and koa are erroneous. Atkinson did not develop S/Rrelationships for alkyl carboxylic acids, peroxides, sulfoxides, and sulfates because of the very limited availability of experimental koa data. Meylan did develop S/Rrelationships for these classes of compounds; however, for a few reasons, these S/Rrelationships are not valid. For the alkyl carboxylic acids and hydroperoxides,
XV tMeylanmade an erroneous assumption about the mechanism of OH reaction for these compounds. For example, for the S/R relationships of the alkyl carboxylic acids, Meylan assumed that OH radicals can react with these compounds by H-atom abstraction from the hydroxyl group in the carboxylic acid group {C(=O)OH, [k(2)]} and from the c-H groups inthe alkyl group [k(1a)] and that the dominant reactionpathwaywas H-atom abstraction from the alkyl group. As a result, Meylan assumed that k(-OH) = 0.036, the same value as assigned toH-atom abstraction from the hydroxyl group in alcohols and glycols. However, based on the analysis of the experimental data ofWine et al. (1986) and Singleton et al. (1986), Atkinson (1989) and Leifer concluded that the major reactionpathwaywas H-atom abstraction from the hydroxyl group andk(-OH) > k(1a). Therefore, it is recommended that the S/Rrelationships for the alkyl carboxylic acids and hydroperoxides be deleted from AOP. More experimental koH data

are needed for additional alkyl carboxylic acids and hydroperoxides to develop reliable S/Rrelationships. For the alkyl sulfoxides, Meylan developed S/R relationships by assuming that only C-H abstraction from the alkyl groups occurred. However, intuitively, it is expected that the sulfoxidegroupwouldundergo further oxidation to the sulfone. Therefore, considerablymore experimental koH data are needed for additional sulfoxides before reliablemechanisms and S/Rrelations are developed; and these S/Rrelationships should be deleted from AOP. xviBased on the very limited data of the alkyl sulfates (only dimethyl and diethyl sulfate), Meylan developed S/R relationships for this class of compounds. Comparison of the estimated koH data with the experimental k08 indicated that dimethyl sulfate gave an error of > +250% and diethyl sulfate gave an error of +540%. These results are very poor so that it is recommended that these S/Rrelationships be deleted from AOP until considerablymore experimental k08 data is available for additional sulfates to develop reliable S/Rrelationships. Meylan, inAOP, used the S/Rrelationships of Atkinson for the nitroalkanes based on the available experimental k08 data for these compounds. However, itmust be emphasized that some of the experimental data is suspect because nitroalkanes are very labileto direct photolysis and it is not clearwhether photolysis occurredunder the experimental conditions of the relative rate study of Nielson et al. (1988) or whether photolysis was taken into account. Therefore, it is recommended thatAOP delete these S/Rrelationships. More reliable experimental koH data are needed for these nitroalkanes under carefully controlled experimental conditions to eliminate, or account for, direct photolysis in order to develop more reliable S/Rrelationships. Comparison of the experimental values of k08 from AOP and Leifer for 454 chemicals indicates that, in general, the agreement is excellent. There are, however, a few differences. The primarydifference is related to the number of significant xviifigures used inAOP. For example, for 2-methylpentane, AOP lists an experimental value of 5.60 while Atkinson (1989) and Leifer {1992a) list a recommended value of 5.6; for 2,3- dimethyl-2-butene, AOP lists a value of 110.0 while the recommended value by Atkinson and Leifer is 110; for dimethylhydroxylamine, AOP lists a value of 90.0 while Atkinson and Leifer recommend a value of 90; for

**~-cresol,** AOP lists a value of 47.0 while Atkinson and Leifer recommend a value of 47; for 4-chlorobiphenyl, AOP lists a value of 3.9 while Atkinson and Leifer list a value of 3.86. For other chemicals with differences, Leifer lists an average value from the literature while AOP selects one set. For example, for trans-1,4-hexadiene, Leifer lists an average value of 90.6 from two sets of experimental data while AOP selects only one value, namely 90.3; for 2,3-dimethyl-2-pentene, AOP selects one valuewhich is 108.0 while Leifer cites an average value of 103 based on both sets of experimental data. Unless there is good reason for discarding specific sets of experimental koa data, it is better to use an average value from both sets. For 12 chemicals, AOP does not list experimental values: for example, four ketenes;

**~3-carene;** sec-butyl acetate; and 2- (chloromethyl)-3-chloro-1-propene. Differences were observed for a few compounds: e.g., for methane, AOP lists a value of 0.00841 while Atkinson and Leifer list a recommended value of 0.00836; for 2-octanone, AOP lists a value of 10.0 while

**xvi~i**Atkinson and Leifer list a value of 11.0; for 1,1,1-trifluoroethane, AOP lists a value of 0.017 while Atkinson and Leifer list a value of 0.0017.



### xixI. Introduction Numerous chemicals, both natural and anthropogenic, are emitted to the troposphere from a variety of sources and may be removed by wet or dry deposition or by three important transformation processes. These three transformation processes
are: (1) directphotoreactionwhich involves the absorption of sunlight followed by transformation; (2) indirectphotoreactionwhich involves the reaction of a chemical withhydroxyl radicals (OH); and (3) oxidationwhich involves the reaction of a chemical with ozone (03). There is another indirectphotoreactionprocess which involves the reaction of a chemicalwith nitrate radicals (N03) during the night. However, this transformationprocess only occurs for a few types of chemicals (e.g., olefins, phenols, and cresols); hence, itwill not be consideredwhen determining the rate of transformation in the troposphere. Aquantitativemeasure of the three important transformationprocesses is given by the rate constants kdEr k0a, and ko • The rate constantkdE represents the first-order 3 rate constant for direct photoreaction, while koa and ko3 represent second-order rate constants for indirect photoreaction and oxidationwith OH and o3, respectively. -1-The first report in a series titled "DETERMINATION OF RATES OF REACTION IN THE GAS-PHASE IN THE TROPOSPHERE. THEORY AND PRACTICE" describes a hierarchal test scheme for determining the rate constants kdE' k0H, and k03 and the half-lives (tc1/2)El for each transformation process and the net half-life in the troposphere [Leifer (1989a)]. The second report describes a screening-level test guideline for determining the maximum rate of direct photoreaction [kdElmax and the minimum half-life [t(1/2)Elmin by the use of Ultraviolet-Visible Absorption Spectroscopy [Leifer (1989b)]. The third and fourth reports in this series describe structure/reactivity (S/R) relationships for estimatingkoH for the reaction of an organic chemical with hydroxyl radicals in the gas-phase in the troposphere. These methods were developed byAtkinson (1986, 1986a, 1987, 1987a, 1988) for the Exposure Assessment Branch of the Office of PollutionPrevention and Taxies, 

## u.s. Environmental ProtectionAgency. Report No. 4 [Leifer (1992b)] represents a test guideline [§796.3900] for use in sections 4 and 5 of the Toxic Substances Control Act; report No. 3 [Leifer (1992a)] represents the technical support document for this test guideline. Since these S/Rrelationships are excellent [Leifer (1992a)], theyhave been computerized by Syracuse Research Corporation [Meylan (1990a, 1990b)]. At the suggestion of Leifer, Syracuse incorporated a data base in this computer programwhich lists the experimental values of koH as reported -2-in the literature [Meylan (1990b)]. This document, describes an assessment of this computer program for estimating k08 and represents report No.5 in this series. II. Mathematical Synopsis of the Structure/Reactivity Relationships of Atkinson andMeylan Atkinson (1986, 1986a, 1987, 1987b, 1988, 1988a) critically analyzed the hydroxyl radical rate data (koa> for a large number of organic chemicals and developed a number of S/Rrelationships based solely on the molecular structure of these·.chemicals. In developing these S/Rrelationships, he assumed that a number of OH radical reactionpathways exist and the various OH radical reactionpathways couldbe separated and treated individually. Therefore, he calculatedrate constants for each of these reactionpathways. The reaction pathways and rate constants for each of these pathways were:

### H-atom abstraction from acyclic ] k(1) = k saturated, cyclic saturated, and unsaturated c-H groups by OH radicals
k(2) = k ra-atom abstraction from 0-H groups] Lby OH radicals 

# r OH radical addition to >C=C<, ] k(J) = k >C=C-C=C<, -C•C-, and >C=C=C<, >C=C=O groups k(4) k [OH radical interactionwith -SH,] = 

### -s-, and

### -s-s- groups k(S) = k [OH radical interaction >NH, and >N- groups with -NH2']
-3- (1)

(2)

(3)

(4)
(5)k(6)
k(7) = k roH radical interaction with] lPhosphorus groups

= k [OH radical addition to aromatic rings]

### H radical addition to fused ringJ k(8) = k polyaromatic compounds (i.e., olyaromatichydrocarbons) (6)
(7)
(8)
Atkinsonpostulatedthat the overall OH radical rate constant k08 is equal to the sum of the rate constants for each of these reactionpathways. Therefore, the OH radical rate constant is given by the equation

8 

### koH

### =

# L k(i) I • 1 (9)

and the individual rate constants [k(1), k(2), ·····, k(8)J and koH are all in the units cm3molecule-1s-1. Structure; reactivity relationships will be described for each of these reactionpathways. Pathway 1: H-atom abstraction from acyclic and cyclic saturated and unsaturated C-H groups by OH radicals The overall rate constant for reaction pathway 1 is given by the equation k(1) = k(1a) +k(1c) + k(1, UNS CH) (10) where k(1a) represents the rate constant for H-atom abstraction from all acyclic saturated C-H groups by OH radicals at 298 

### K; -4-k(1c) represents the rate constant for H-atom abstraction from all cyclic saturated C-H groups by OH radicals at 298 K; and k(1, UNS CH) represents the rate constant for H-atom abstraction from all unsaturated c-H groups (e.g.,=C-H) by OH radicals at 298 

### K. The rate constantk(1a) is given by themathematical relationship k(1a} =**~** 

## ms

k(1c) =

### l~ ;tr, k(1, UNS CH} = 0 (11)

(12)
(13)
where**k~,** kg,**k~** represent the group rate constants for primary (CH3-), secondary (>CH2), and tertiary (>CH-) groups, respectively, and the values for these parameters at 298 Kare listed inTable 1 of an EPA report by Leifer (1992a), inTable 1 of a report byMeylan (1990b}3, and inTable 1, Section IV, of this report;

### ~**~** 

# L**~** 

# L represent the 

## ms I 

### .tr.S 1 111(8) 1 

### rtt, I III(C) 1 summation over all primary acyclic, secondary acyclic, tertiary acyclic, secondary and tertiary cyclic groups, respectively, in

3 Group Rate Constants and SubstituentValues Used by the Atmospheric Oxidation Program, Version 1.30, November 1, 1990.



### -s-the molecule; F(X), F(Y), F(Z) represent the substituent factors for substituents X, Y, and 

### Zand the values for various substituents at 298 

### Kare listed in Table 2 of an EPA report by Leifer (1992a), in Table 6 of a report by Meylan (1990b)3

, and in Table 2, Section IV, of this report; F(n) represents the ring strain factor for saturated and unsaturated rings and heterocyclic rings containing n (3,4,5) atoms at 298 K and the values are listed inTable 2 of an EPA report by Leifer (1992a), inTable 10 of a report byMeylan (1990b)3, and in Table 3, Section IV, of this report. For rings with n(6,7,8, etc.), with essentially no ring strain, F(n)**~** 1.0 at 298 K. Patbway 2: H-Atom abstraction from -0-H groups in alcohols and glycols by OH radicals The overall rate constant for reaction pathway 2 is given by the equation k(2) = n(-0-H) k(-OH) (14) where n(-0-H) represents the number of hydroxyl groups (-0-H) 

### in the molecule; k(-OH) represents the group rate constant for Hatom abstraction from the hydroxyl group 

### in alcohols and glycols and is equal to 0.036 x 1o-12cm3molecule-1s-1 at 298 K [Table 1 of an EPA report by Leifer (1992a), in Table 1 of a report by Meylan (1990b)3
, and in Table 1, Section IV, of this report).

-6- : 

### •Pathway 3: OH radical addition to isolated alkene groups (>C=C<), nonaromatic conjugated groups (>C=C-C=C<), and other unsaturated groups (-C•C-, >C=C=C<, >C=C=O) The overall rate constant for reaction pathway 3 is given by the equation k(3) = kadd,nar

=**~kAsci(X)Ci(Y)** +**~kg cj(X)Cj{Y)**  +

+

# l:kgucm(X)Cm(Y) 

## • (15)

where kAs, kgo, kgu represent the group rate constants for OH radical addition (add) to isolated (is) carbon-carbon double bonds, nonaromatic (nar) conjugated (co) carbon-carbon bond systems, and otherunsaturated (ou) carbon-carbon systems, respectively, and the values of these group rate constants at 298 Kare given inTables 9, 11, and 12, respectively, of an EPA report by Leifer (1992a), in Tables 2, 5, (3 and 4), respectively, of a report byMeylan (1990b)3
, and in Tables 4, 5, {6 and 7), respectively, Section IV, of this report;

# l:'l:,
1 J 

# l:, represent the summation over all isolated carbon-carbon 

## • double bond systems, nonaromatic conjugated carbon-carbon double bond systems, and otherunsaturated carbon-carbon groups, respectively, in themolecule; C(X) and C{Y) represent the substituent factors at 298 Kfor substituents Xand Yand are listed inTable 10 of an EPA report by Leifer (1992a), in Table

-7-7 of a report by Meylan (1990b)3
, and in Table 

### a, Section IV, of this report. Pathway 4: OH radical interactionwith -SH, 

### -s-, and

### -s-sgroups The overall rate constant for reactionpathway 4 is given by the equation k(4)**~** n(-SH)k(-SH) + n(-S-)k(-S-) + n(-S-S-)k(-S-S-) (16) where n(-SH), n(-S-), and n(-S-S-) represent the number of -SH, 

### -s-, and

### -s-s- groups, respectively, in the molecule; k(-SH), k(-S-), k(-S-S-) represent the group rate constants for OH radical interactionwith the -SH, 

### -s-, and

### -s-s- groups, respectively, and the values of these group rate constants at 298 Kare listed in Table 1 of an EPA report by Leifer (1992a), in Table 1 of a report byMeylan (1990b} 3, and in Table 1, Section IV, of this report. Patbway 5: OH radical interactionwith -NH2, >NH, and >Ngroups The overall rate constant for reaction pathway 5 is given by the equation k(S} 

## =n(-NH2}k(-NH2} + n(>NH)k(>NH} + n{>N-}k(>N-) (17) where n(-NH2), n{>NH), n(>N-) represent the number of -NH2, >NH, and >N- groups, respectively, in the molecule; k(-NH2), k(>NH), k(>N-) represent the group rate constants for -NH2, >NH, and >N-, respectively, and the values of these group rate constants



### -a-•

....

at 298 Kare listed in Table 1 of an EPA report by Leifer (1992a), inTable 1 of a report by Meylan (1990b)3
, and in Table 1, Section 

### IV, of this report. Pathway 6: OH radical interactionwith phosphorous groups The overall rate constant for reaction pathway 6 is given by the equation k(6) = n[>P(S)-]k[>P(S)-] + n[>P(O)-]k[>P(O)-] + n[>P(Cl)<] k[>P(Cl)<] (18)

where n[>P(S)-],**n[>~(O)],** n[>P(Cl)<] represent the number of >P(S)-, >P(O)-, and >P(Cl)< groups, respectively, in the molecule; k[>P(S)-], k[>P(O)-], k[>P(Cl)<] represent the group rate constants for OH radical interaction with the >P(S)-, >P(O)-, and >P(Cl)< groups, respectively, and the values of these group rate constants at 298 

### Kare listed in Table 1 of an EPA report by Leifer (1992a), inTable 1 of a report by Meylan (1990b)3, and inTable 1, Section 

### IV, of this report. Pathway 7: OH radical addition to aromatic rings The overall rate constant k(7)[=kadd,arl for reaction pathway 7 is given by the equation k(7) = k(7A) + k(7B) (19)
where k(7A) corresponds to the addition of OH radicals to an aromatic ring (ar) and k(7B) corresponds to OH reaction with an heteroaromatic (monocyclic) ring (ar').

-9-For reaction of OH radicals with an aromatic ring k(?A) = kadd,ar {20)

### log1ok~add,ar =

### ~ [0.31- 1.35 Min {

### ~aj**~** {21)

kadd,ar

## =10-12 kadd,ar {22) where

### ~ represents the summation over all aromatic rings in the molecule; <l:aj) represents the summation of the electrophilic J substituent constants of Brown and Okamoto {1958) with respect to a given ring position 

### (i.e., ortho, meta, para); and Min{l:aj) J aj ) represents the summation of the electrophilic substituent constants with respect to the ring hydrogen position that gives the most negative summation value 

### (i.e., Min). Electrophilic substituent constants**(a~** and**a~)** for a number of substituents
are given in Table 22 of an EPA report by Leifer {1992a), in Table 8 of a report byMeylan {1990b)3, and in Table 9, Section IV, of this report. Atkinson did not develop S/Rrelationships for OH radical addition to a heteroaromatic ring (monocyclic) while Meylan (1990b)4 did develop S/Rrelationships. For OH radical addition to the heteroaromatic ring (ar'), AOP uses the equation

4 User's Guide for the Atmospheric Oxidation Program, Version 1.10, November 1, 1990.

-10-k(7B) 

## =kadd,ar' (23) log1okadd ar' 

## =l: [Ai

- 1.35 Min ( l:aj )]

, 1 J (24)

where l: represents the summation over all heteroaromatic rings, 1 Ai is a function of the experimental value of kadd,ar' of the basic, or parent, heteroaromatic ring in the units 10-12 cm3molecule-1s-1 [Table 10, Section IV, of this report and on page 7 of a document byMeylan (1990b)4]; and the other parameters have been described previously. The use of equations 23 and 24 will be discussed in more detail in Section IV.B. Pathway 8: OH radical addition to fused ring polyaromatic compounds The overall rate constant k(8) for reaction pathway 8 is given by the equation k(8) 

## =k(8A) +k(8B) (25) where k(8A) corresponds to the addition of OH radicals to a polynuclear aromatic hydrocarbon ring (PAH) and k(8B) corresponds to the OH radical addition of OH radicals to a polynuclear heteroaromatic ring (PAH'). For OH addition to the polyaromatic hydrocarbon ring k(8A) 

## =kadd,PAH (26)

= l:[10.11- 1.08 (IP)i- 1.35 Min( l:aj)] (27) 1

-11-(28) where l: represents the summation of all PAHs, (IP)i represents I the ionizationpotential of the parent PAH in electron volts (eV) obtained fromWeast {1976-1977); {l:aj) is derived for the J monocyclic substitutedportion of the molecule to allow for the effects of substituent qroups on the reactivity and represents the summation of the electrophilic substituent constants of Brown and Okamoto (1958) with respect to a qiven 

### rinq position (i.e., ortho, meta, para); andMin ( l:aj) represents the summation of J the electrophilic substituent constants with respect to the ring hydroqen position that qives the most neqative summation (i.e., Min). Electrophilic substituent constants

**{a~** and

**a~)** for a number of substituents are qiven inTable 22 of an EPA report by Leifer {1992a), inTable 8 of a report byMeylan (1990b)3
, and in Table 9, Section IV, of this report. For OH radical addition to fused polynuclear aromatic hydrocarbon rinqs, Meylan (1990b)3
, developed a different approach to estimatekadd,PAH· Meylan, inAOP, uses the equation loq10kadd PAH = l: [Bi

- 1.35 de+ ] I I ) (29)
where l: represents the summation over all fused polynuclear I aromatichydrocarbon rinqs, Bi is a function of the experimental value of kadd,PAH of the basic, or parent, polynuclear hydrocarbon aromatic rinq in the units 1o-12cm3molecule-ls-l
-12-[Table 11, Section IV, of this report and from Meylan (1990b)4 for naphthalene, anthracene, and phenanthrene] or is given an assigned value basedprimarily on the experimental ionization potential of the basic, or parent, polynuclear aromatic hydrocarbon ring intheunits 1o-12cm3molecule-1s-1 [Table 12, Section IV, of this report and from Meylan (1990b)4] for 4, 

### s, and 6 fused benzene rings. The termdej is related to the substituent factors

**a~** and

**a~** for various substituents and is determined inthe following way. For monosubstituted PAH compounds, dej corresponds to themost negative value of a+ mor a+ p for a given substituent on the ring. For polysubstitutedPAH compounds, dej corresponds to the sum of the average values of

**a~** and

**a~** for each substituent on both rings. For OH radical addition topolynuclear heteroaromatic rings (PAH'), Meylan (1990b)4 uses a modified form of equation 29 which is

=

# l:[Bi 1 - 1.35 de"! J (30) 

## ' where Bi is now related to the experimental ionization potential of the basic, or parent, fused polynuclear heteroaromatic ring in the units 1o-12cm3molecule-1s-1 [obtained from Table 13, Section IV, of this report for a few fused polynuclear heteroaromatic rings and from Meylan (1990b)4]. The term dej is the same as the
one described previously. It should be noted that at present, 

## ' AOP cannot estimatekadd,PAH for fused ring structures contain- -13-ing five-membered heterocyclic rings. The use of equations 29 and 30 will be discussed in more detail in Section IV.B. III. Syracuse Research CorporationAtmospheric Oxidation computer Program (Developed byMeylan) III.A. Introduction The Atmospheric Oxidation Computer Program [designated as AOP] was purchased from Syracuse Research Corporationby the Exposure Assessment Branch of the Office of Pollution Prevention and Taxies, 

## u.s. Environmental ProtectionAgency, based on the recommendation of Leifer. The first version, labeledVersion 1.00, was receivedJuly 10, 1990 (Meylan (1990a)]. The Atmospheric Oxidation Program estimates the second-order rate constant for the reaction of an organic chemical with hydroxyl radicals CkoH> and ozone (k03) in the gas-phase. These rate constants are then used to calculate the half-life [tc1;2)El for these two reaction pathways based on average hydroxyl radical and ozone concentrations in the troposphere. Based on a verypreliminary evaluation of the hydroxyl radical portion of this program, a few errors were uncovered. After a discussion byphone withMeylan on August 2, 1990, changes were made inthe hydroxyl radical portion of this program. The new AOP computer program, Version 1.30, was received on November 1, 1990 and contained a data base for experimental values for the reaction of organic chemicals with hydroxyl radicals (koH), ozone (k03), and nitrate radicals (kNo3). This report covers the evaluation of the hydroxyl -14-

# ..

radical portion of AOP. Future EPA reports will be devoted to the discussion of the 5/Rrelationships of Atkinson and Carter (1984) for ozone and the evaluation of AOP for estimating k03 and the corresponding half-life [t(1/2)EJ· III.B. Atmospheric Oxidation Computer Program (AOP) The estimationmethods used inAOP are based on the structure/reactivityrelationships of Atkinson (1986, 1986a, 1987, 1987a, 1988, 1988a) for the gas-phase reaction of hydroxyl radicals with organic chemicals in the troposphere as described in detail inthe report by Leifer (1992a) and the structure/ reactivity relationships of Atkinson and carter (1984) for the gas-phase reaction of ozone with organic chemicals in the troposphere. As stated in Section III.A., only the AOP program for estimatingk08 and tc1/2)E will be discussed in this report. AOP has been designed for use in an IBM or an IBM-compatible series of personal computers running theMS-DOS or PC-DOS operating systems. Approximately 350 Kof free memory are required to run AOP. All program outputs occur in the text mode and are run from a floppy disk drive. TheAOP program is startedby pressing key F-8 of the WorkstationMenu, typing inAOP, and then pressing the Enter key. Program execution begins by displaying the data input screen shown in Figure 1. The program version and date are displayed in the upper left corner of the screen. The present version is specified in three lines:Version:/SRC 1.30/Nov 1990. The large -15-Figure 1. Atmospheric Oxidation Program Data Entry Display

Version: IHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH; SRC 1.30 : ATMOSPHERIC OXIDATION PROGRAM : Nov 1990 : Rate of Hydroxyl Radical &Ozone : : Reaction from Chemical Structure : HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH( 

# ...

IHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH; 

### :oooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo: : Enter SMILES:O 000: :000000000000000 000: 

### :oooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo: : Enter NAME :0 000: :000000000000000000000000000000000000000000000000000000000000000000000000000000: HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH<

INS: OFF ZDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD? 3 Fl: CLEAR Input F6: Save Input to User File PgDn: CALCULATE 3 3 F2: PREVIOUS Input F8: CAS File Input Alt-H: SMILES HELP 3 3 F4: User FILE Input FlO: CALC &SAVE Results Esc: EXIT to DOS 3**~DDDDDDDDDDDDDDDDDDDDDODDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDY**

-16-rectangular box in the upper center of the screen contains the program name and purpose. Alarge box in the middle portion of the screen is used to enter the SMILES notation corresponding to the chemical to be used in the estimation. The SMILES notation is a computer readable molecular structure system. Currently, a maximum of 120 characters are allotted for the SMILES notation. Directlybelow the Enter SMILES box, is a boxwith Enter NAME. This box is used to enter the name of the chemical and a maximum of 60 characters are allotted for this purpose. The blank space in the lowerportion of the screen is used to display error messages correspondingto the SMILES entry. Finally, the lower box contains the various editkeys. The reader is referred to the USERS GUIDE for AOP, Version 1.10, prepared byWilliamMeylan of SyracuseResearch Corporation, for a detailed discussion of the operation of AOP. The only data required for AOP toproduce estimated and experimental values of koa and tc1/2)E is the SMILES notation corresponding to the molecular structure of the chemical. The
name of the chemical is optional and is not required to run AOP. As an illustrationof the operation of AOP and the output data to themonitor screen, consider the chemical a-methyl styrene, (2-phenyl-1-propene) which has a SMILES notation C=C(C)c1ccccc1. This SMILES notation is entered at the point adjacent to the ENTER SMILES notation on the screen and pressingkey PgDn. If the SMILES notation is correct, the data entry screen is removed and the koa data are displayed on the screen, Figure 2.A. The -17-Figure 2. Atmospheric Oxidation Program Data Display for the Compound a-Methyl Styrene (2-Phenyl-1-Propene): Summary Hydroxyl Radical Data and Experimental Data. Figure 2A A. Screen Display when Key PgDn is pressed.

SMILES : C=C<C>c1ccccc1 CHEM MOL FOR: C9 H10 MOL WT : 118.18

---·---------------------- SUMMARY: HYDROXYL RADICALS

------------------------- Hydrogen Abstraction = Reaction with N, S and -OH = Addition to Triple Bonds = ** Addition to Olefinic Bonds = ** Addition to Aromatic Rings = Addition to Fused Rings = .1440 E-12 cm3/molecule-sec .0000 E-12 cm3/molecule-sec .0000 E-12 cm3/molecule-sec

51.4000 E-12 cm3/molecule-sec

1.9187 E-12 cm3/molecule-sec .0000 E-12 cm3/molecule-sec OVERALL yOH Rate Constant = 53.4627 E-12 cm3/molecule-sec HALF-LIFE = .300 Days (at cone 5E5 yOH/cm3) .........•.....•........ **Designates Estimation(s) Using ASSUMED Value(s) ZDDDDDDDDDDDDDDDDDDDDDD4 EXPERIMENTAL DATA CDDDDDDDDDDDDDDDDDDDDDDDDDD? -----3 3-- 0V3 Name: 2-Phenyl-1-propene <<-methyl styrene) 3 HA3 CAS Number: 00098-83-9 3 3 Exper OH rate constant 52.0 E-12 cm3/molecule-sec 3 3 Exper Ozone rate constant cm3/molecule-sec 3 3 Exper N03 rate constant cm3/molecule-sec 3 3 3 3 3 @DDDDDDDDDDDDDDDDDD4 Press any key to continue

... CDDDDDDDDDDDDDDDDDDDY

-18-Fiaure 2B B. Screen Display when Key F-10 is pressed.

SMILES : C=C<C)c1ccccc1 CHEM MOL FOR: C9 1-110 MOL WT : 118.18 INNHNMHHMHHHMMMHHMMMMM: : Summary Saved to:
. : file --) AOP1.DAT

.**HHHHMMMHMMHMMHNHHNNNMM~**

------------------------- SUMMARY: HYDROXYL RADICALS

------------------------- Hydrogen Abstraction = Reaction with N, S and -OH = Addition to Triple Bonds = ** Addition to Olefinic Bon·ds = ** Addition to Aromatic Rings 

### = Addition to Fused Rings = . 1440 E-12 cm3/molecule-sec .0000 E-12 cm3/molecule-sec .0000 E-12 cm3/molecule-sec

51.4000 E-12 cm3/molecule-sec

1.9187 E-12 cm3/molecule-sec .0000 E-12 cm3/molecule-sec OVERALL yOH Rate Constant 

### = 53.4627 E-12 cm3/molecule-sec HALF-LIFE

## = .300 Days Cat cone 5E5 yOH/cm3> ........•.••...•.•....•• **Designates Estimation(s) Using ASSUMED 'v'.:.due(s) ZDDDDDDDDDDDDDDDDDDDDDD4 EXPERIMENTAL DATA CDDDDDDDDDDDDDDDDDDDDDDDDDD? -----3 3-- 0V.3 Name: 2-Pheny1-1-pt'opene <cC.-methy1 styt'ene) 3 HAJ CAS Number: 00098-83-9 3 3 Exper OH rate constant J Exper Ozone rate constant 3 Exper N03**rat~** constant 3 3 52.(> E-12 cm3/molecule-sec cm3/molecule-sec cm3/molecule-sec
@DDDDDDDDDDDDDDDDDD4 Press any key to continue

... 3 CDDDDDDDDDDDDDDDDDDDY

-19-SMILES notation, molecular formula, and molecular "rqight of a-methyl styrene are displayed at the top left portion of the screen. Directly below these data and in the center of the screen, this figure displays the SUMMARY: HYDROXYL RADICALS data and the EXPERIMENTAL DATA. Directly under SUMMARY: HYDROXYL RADICALS, the estimated rate constants for each of the specific reaction pathways (ki) for a-methyl styrene are listed. Immediately below the summary data, the overall koH rate

**constar~** {which represents the sum of each of the individual rate constants [k(i)]} and the corresponding half-life are listed. The half-life (in days) corresponds to an average OH radical concentration of 5E5 radicals cm-3 and a 24-hour daylight day. The table in the lower box summarizes the available experimental k0H, k03, and kNOJ data for this compound. The experimental value of koH is listed as 52.0 E-12 cm3molecule-1s-1 as obtained from Atkinson (1989). No experimental rate data are available for the reaction of a-methyl styrene with ozone (k03) and with nitrate radicals (kNo3). If, after the SMILES notation for a-methyl styrene is entered, key F-10 is pressed instead of PgDn, the results are then displayed on the screen as shown in Figure 2.B. In this case, the estimated and experimental data are the same as the data in Figure 2.A. except that the estimated data are now stored in a file as indicated in the top right corner box. Pressing key PgDn displays the same OH rate data but now the SUMMARY: OZONE REACTION data replaces the available experimental -20-data, Figure JA. The ozone data corresponds to the overall estimated ozone rate constant (k03) and the associated half-life [t(1/2)El in days corresponding to an average ozone concentration of 7E11 molecules cm-3 and a 24-hour day. If, after the SMILES notation for a-methyl styrene is entered, key F-10 is pressed twice, then the results are depicted in Figure J.B. In this case, the estimated data is the same as the data displayed in Figure 3.A. except that the data is now stored in a file as indicated in the box in the upper right corner. When pressingkey F-9 five times, the screen displays sequentially for a-methyl styrene: (1) the detailed calculations for hydrogen abstraction [k(1a)], Figure 4.A.; (2) OH addition to the olefinic group [k(3) = kadd,narl, Figure 4.B.; (3) ozone reaction with the olefinic group, Figure S.A.; (4) OH addition to the aromatic ring (ar) [k(7A) 

## = kadd,ar], Figure S.B; and (5) Figure 6, which corresponds to the same estimated data for OH addition to the aromatic ring (Figure S.B.) and the experimental data in the lower box corresponds to the same experimental data displayed in Figure 2.A. If key F-9 is pressed again five times, the same sequence of data is displayed as described above. Pressing any key but F-9 returns the screen display to Figure 1 for entry of a SMILES notation for another compound. If key F-2 is pressed, Figure 1 -21-Figure 3. Atmospheric Oxidation Program Data Display for the Compound a-Methyl Styrene (2-Phenyl-1-Propene): Summary Hydroxyl Radical and Ozone Data. Fiaure JA A. Screen Display when Key PgDn is pressed.

SMILES : C=C<C)clcccccl CHEM MOL FOR: C9 H10 MOL WT : 118.18 ;

------------------------- SUMMARY: HYDROXYL RADICALS

------------------------- Hydrogen Abstraction = Reaction with N, S and -OH = Addition to Triple Bonds = 

### ** Addition to Olefinic Bonds = 

### ** Addition to Aromatic Rings = Addition to Fused Rings = .1440 E-12 cm3/molecule-sec .0000 E-12 cm3/molecule-sec .0000 E-12 cm3/molecule-sec

51.4000 E-12 cm3/molecule-sec

1.9187 E-12 cm3/molecule-sec .0000 E-12 cm3/molecule-sec OVERALL yOH Rate Constant 

## = 53.4627 E-12 cm3/molecule-sec HALF-LIFE 

### = .300 Days Cat cone 5E5 y0H/cm3)



### . . . .... . . . . . . . . . . . . . . . . . ** Designates Estimation(s) Using ASSUMED lialue(s)

------------------------- SUMMARY: OZONE REACTION

---------------------------- OVERALL OZONE Rate Constant = 13.650000 E-17 cm3/molecule-sec HALF-LIFE

## = .084 Days <at cone 7E11 mol/cm3)

Press F9 to Show Calc Press ESC to STOP.•..anything else to continue

-22-

# ...

... Figure 3B B. Screen Display when Key F-10 is pressed.

SMILES : C=C<Clc1ccccc1 CHEM MOL FOR: C9 H10 1"'10L WT : 118.18 IHHNNHNMMHMMMHMMMMNNHM: : Summary Saved to= : file --> AOP1.DAT HMMMNMMMNMNMMNNHNMNHMM·

------------------------- SUMMARY: HYDROXYL RADICALS

------------------------- Hydrogen Abstraction = Reaction with N, S and -OH = Addition to Triple Bonds = 

### ** Addition to Olefinic Bonds = 

### ** Addition to Aromatic Rings = Addition to Fused Rings = .1440 E-12 cm3/molecule-sec .0000 E-12**cm3/molecule~sec** .0000 E-12 cm3/molecule-sec

51.4000 E-12 cm3/molecule-sec

1.9187 E-12 cm3/molecule-sec .0000 E-12 cm3/molecule-sec OVERALL yOH Rate Constant 

### = 53.4627 E-12 cm3/molecule-sec HALF-LIFE 

### = .300 Days (at cone 5E5 yOH/cm3l

. . . . .•.. . . .•.. . . . . . . . . . . **Designates Estimation(s) Using ASSUMED ',,'alue(s)

------------------------- SUMMARY: OZONE REACTION

---------------------------- OVERALL OZONE Rate Constant = 13.650000 E-17 cm3/molecule-sec HALF-LIFE 

### = .084 Days <at cone 7E11 mol/cm3)

Press F9 to Show Calc Press ESC to STOP

....anything else to continue

-23-Figure 4. Atmospheric Oxidation Program Data Display for the Compound a-Methyl Styrene (2-Phenyl-1-Propene): Figure 4A A. Screen Display of the Detailed Calculations for Hydrogen Abstraction.

Hydrogen Abstraction



## ---------------------- Kprim 

### =0.144 FC>C=C<J 

### = 0.144 < 1.000) 

### = .144 H Abstraction TOTAL 

### = .144 E-12 cm3/molecule-sec

Press any key to continue

-24- 

# ...

# ...

... Figure 4B B. Screen Display of the Detailed Calculations for OH Radical Addition to the Olefinic Bond.

OH Addition to Olefinic Bonds



## ------------------------------- Kd

- K<CH2=C<lC<-Phenyl **l 51

.400(1•00) :::: 51.400 E-12 cm3/molecule-sec



## ...... "

## ............................. ASSUMED Value designated by: **

Press any key to continue

-25-Figure 5. Atmospheric Oxidation Program Data Display for the Compound a-Methyl Styrene (2-Phenyl-1-Propene): Figure SA A. Screen Display of the Detailed Calculations with 

### o3 Reaction with the Olefinic Bond.

Ozone Reaction with Olefins



## ------------------------------- ko- K(CH2=C-R2lOx<-CH3l0xC-Aromaticl •175oooc 6.::_;oo> <12.ooo'
- 13.650000 E-17 cm3/molecule-sec

Press any key to continue

-26-Figure SB B. Screen Display of the Detailed Calculations of OH Radical Addition to the Aromatic Ring.

OH Addition to Aromatic Rings



### ------------------------------- de+ 

### = Most negativs value of ep+ or em+ (-C=C **l 

## = Log Kar 

### = -11.69- 1.35 de+ cm3/molecule-sec Ring #1 Kar

- 1.9187 E-12 cm3/molecule-sec TOTAL Kar 

### = 1.9187 E-12 cm3/molecule-sec

......................Assumed values designated by** .020

Press any key to continuE

-27-Figure 6. Atmospheric Oxidation Program Data Display for the Compound a-Methyl Styrene (2-Phenyl-1-Propene): Screen Display for OH Addition to the Aromatic Ring and the Experimental Data.

DH Addition to Aromatic Rings



### ------------------------------- de+ 

### = Most**negativ~** valus of ep+ or em+ (-C=C **) = Log Kar 

### = -11.69

- 1.35 de+ cm3/molecule-sec Ring #1 Kar 

### = 1.9187 E-12 cm31molecule-sec 1.9187 E-12**cm3/mol~cule-sec**

......................Assumed values designated by** .020

ZDDDDDDDDDDDDDDDDDDDDDD4 EXPERIMENTAL DATA CDDDDDDDDDDDDDDDDDDDDDDDDDD? 3' '3 Name: 2-+'heny**l-1-pt~opene (~-methyl**  styt-·ene) J CAS Number: 00098-83-9 3 Exper OH rate constant 52.0 E-12 cm3/molecule-sec 3 Exper Ozone rate constant cm3/molecule-sec 3 Exper N03 rate constant cm3/molecule-sec .3 3 7 ·..J 3 3 3 3 @DDDDDDDDDDDDDDDDDD4 Press any key to continue..• CDDDDDDDDDDDDDODDDDDYe

-28-is reproducedwith the original SMILES notation for a-methyl styrene. IV. Evaluation of theAtmospheric Oxidation Computer Program for Estimatingkoa and the ExperimentallyMeasured koa Data Listed in the Program IV.A. Comments on the Group Rate Constants, Substituent Factors, and Other ParametersUsed by theAtmospheric oxidation Program The group rate constants, substituent factors, and other parameters are listed inTables 1 through 9 for a large number of classes of compounds as obtained fromMeylan (1990b). Afew comments will bemade in this section on the numerical values of theseparameters listed in these tables. More details will be given in Sections IV.C. through IV.F. on specific classes of compounds and specific compounds in each of these classes. First, considerTable 1 which summarizes the group rate constants for hydrogen abstraction and radical reaction. The value of the group rate constantk(>C<) is listed as zero with

one significant figure. However, this value is known much more accurately; conservatively, it isknown to three significant figures. Therefore, it is recommended thatAOP use k(>C<) = 

### o.ooo which is consistentwith the accuracy of the S/R relationships of Atkinson. Table 1 does nothave an entry for H-atom abstraction from unsaturated carbon-carbon functional groups (i.e., =C-H). Even
at temperatures up to 500 K, H-atom abstraction from these functional groups is zero [Atkinson (1987)]. Therefore, it is -29-Table 1. Group Rate Constants for Hydrogen Abstraction and Radical Reaction1 Group Rate.Constant k X1012 cm3/molecule-sec k(-CH3) 0.144 k(-CH2-) 0.838 k(>CH-) 1.83 k(>C<) 0 k(-OH) 0.0362 k(-NH2) 20 k(-NH-) 60 k(>N-) 60 k(-SH) 313 k(-S-) 2.0 k(-S-S-) 200 k(>N-NO) 0 k(>N-N02) 0 k[P(=O)] 0 k[P(=S)] 55

1 Data from Table 1 in Group Rate Constants and Substituent Values Used by the Atmospheric Oxidation Program, Version 1.30, November 1990 [Meylan (1990b)]. 2 This group rate constant is only applicable to hydroxyl groups in alcohols and glycols. 3 Used only for aliphatic connections; connection to aromatics not included based upon experimental rate constant for thiophenol.
-30-Table 2. Substituent F(X) Factors for Hydrogen Abstraction1 (values marked with "**" are estimated/assumed values)
Substituent Factor 1. -CH3 1.00 2. -CH2- 1.29 3. -CH2CL 0.57 4. -CH2Br 0.57 5. -CH2F 0.85 6. -CH2C(•O)- 4.4 7. -CH20N02 0.30 8. -CH2CN 0.5 9. -CH2I ** 0.57 (given aame value aa -CH2Br) 10. >CH- 1.29 11. -CHCL2 0.57 12. -CHF2 .0.10 13. -CHBr2 ** 0.57 (given same value aa -CHCL2) 14. -CHI2 ** 0.57 (given same value as -CHCL2) 15. >CHC(.O)- 4.4 16. >CHON02 0.30 17. >C< 1.29 18. -CCL3 0.09 19. -CF3 0.075 20. -CBr3 ** 0.09 (given same values as -CCL3) 21. -CI3 ** 0.09 (given same values as -CCL3) 22. >CC(•O)- 4.4 23. >CON02 0.30 24. -CF2CL 0.025 25. -F 0.099 26. -CL 0.38 27. -Br 0.30 28. -I ** 0.30 (given aame value as -Br) 29. •0 8.8 30. -Aromatic 1.0 31. -OH 3.4 32. 

### -o- 6.1 33. -ON02 0.18 34. -CN 0.14 35. -OC(•O)R 1.5 36. -C=(O)CL 0.5 37. -C(=O)- 0.76 38. -CHO 0.76 39. -C(•O)OR 

### o.o 40. >C•C< 1.0 41. -C•C- 1.0 42. -SH 9.0

-31-Table 2. Continued Substituent 43. 

### -s44. 

### -ss45. -NH2 46. -NH47. -N< 48. -NNO 49. -NN02 

### so. -N02 51. -OP52. -SP53. -P- ** 54. •P ** 

### ss. •N ** 56. •S ** 57. CH-Halogen ** 58. S(+4)•0 ** 59. blank 60. Missing 61. -cH-2Halogens ** 62. -C-3Halogens ** 63. -CHP-Halogen ** 64. 

### -o-o- ** 65. -O-N• ** 66. >CN02 ** 67. >CHN02 ** 68. CH2-N02 69. CH2-0- 70. 2nd-o71. Sulfonic acid ** 72. 2nd alkyl ketone 73. -CH(Halogen)C•O ** 74. -CH(N02)C•O ** 75. -CH(N02)Halogen ** 76. >e(N02)c-o- ** 77. >C(ON02)C•o- ** 78. -CH(ON02)C-o ** 79. >C-0- ** Factor 9.0 9.0 10 10 10 10 10

0.18 20 20 1.0 1.0 1.0 9.0 0.57 99.0

1.0 0.0 0.57 0.09 0.30 

### so

2.0 0.30 0.30 0.30 4.50 1.00 0.20 1.00 3.10 1.3 0.21 1.3 1.3 1.3 4.5 (new Atkinson value) (arbitrarily assigned a value of unity) (arbitrarily assigned a value of unity) (arbitrarily assigned a value of unity) (given same value as sulfur #a 42, 43, 44) (estimatedbyAsa Leifer) (baaed on dimethyl sulfoxide data) (given same value as -CHCL2) (given same value as -CCL3) (assigned a value between -CHF2 and -CHCL2) (baaed on experimental OH rate constants for methyl and t-butyl hydroperoxides) (arbitrarily assigned based on other values for oxygen and nitrogen connections) (given same value as 68) (given same value as 68) (new nitroalkane data) (new Atkinson value) (new Atkinson value) (arbitrary estimate) (data for cyclobutanone) (combination of previous) (combination of previous) (combination of previous) (combination of previous) (combination of previous) (combination of previous) (given same value as CH2-0-)

Data from Table 6 inGroup Rate Constants and Substituent Values Used by the Atmospheric Oxidation Program, Version 1.30, November 1990 (Meylan (1990b)].

-32-

### ••
Table 3. Factors Used for Aliphatic Ring Strain Effects1 Factor 3-Membered Ring 0.017 4-Membered Ring 0.22 5-Membered Ring 0.80 6-Membered Ring 1.00 7 to 10-Membered Ring 1002

1 Data from Table 10 in Group Rate Constants and Substituent Values Used by the Atmospheric Oxidation Program, Version 1.30, November 1990 [Meylan {1990b)]. 2 Note: aliphatic rings containingmore than 10 members do not have any ring strain effect factor applied to them.

-33-Table 4. Group Rate Constants for OH Radical Addition to Isolated Olefinic Units1

structure k

## x 1o12 cm3;molecule-sec CH2=CH- 26.3 CH2•CH< 51.4 -CH=CH- (cis-) 56.1 -CH=CH- (trans-) 63.7 -CH=C< 86.9 >C=C< 110.0 -CH=CH- (cyclic) 56.12

1 Data from Table 2 in Group Rate Constants and Substituent Values Used by the Atmospheric Oxidation Program, Version 1.30, November 1990 (Meylan (1990b)]. 2 The group rate constant for cyclic alkenes such as cyclopentene and cyclohexene is assumed to be the same as the cis-iosmer value although the trans-isomer value yields slightly better estimates.

-34- 

# ..

# ... Table 5. Group Rate Constants for OH Radical Addition to Conjugated Olefinic Units1

No. Alkyl Groups 1 1 StructureCH2=CH-CH=CHCH2=CH-<f=CH2 k X 1012 cm3jmolecule-sec 105 105



# ----------------------------------------------------------------- 2 CH2=CH-CH=C< 135 2 CH2=CH-<f=CH- 135
2 CH2=<f-CH=CH- 135
2 -CH=CH-CH=CH- 135 2 CH2=y-<f=CH2 135



# ----------------------------------------------------------------- 3 CH2=CH-y=C< 180
3 CH2=y-CH=C< 180
3 -CH=CH-CH=C< 180 3 CH2=y-y=CH- 180
3 -CH=CH-y=CH- 180



# -----------------------------------------------------------------

-35-Table 5. Continued

No. Alkyl Groups Structure k X1o12 cm3/molecule-sec 4 >C=CH-CH=C< 230 4 -CH=C-CH=C< 230 I 4 -CH=CH-C=C< 230 I 4 CH2=C-C=C< 230 I I 4 -CH•C-C-CH- 230 I I



# ----------------------------------------------------------------- 5 >C=C-C=CH1 I 5 >C=CH-r=C<



# ----------------------------------------------------------------- 6 >C=r-r=C<

1 Data from Table 5 in Group Rate Constants and Substituent Values Used by the Atmospheric Oxidation Program, Version 1.30, November 1990 [Meylan (1990b)]. 2 These values have been estimated.•••estimates are based upon the increasing relationship for the 1 to 4 alkyl group structures.

-36-Table 6. Group Rate Constants for OH Radical Addition to Alkyne Units1

Structure k 

### X1012 cm3fmolecule-sec
CH•C- 6.4 

## -esc- 29.0

1 Data from Table 3 in Group Rate constants and Substituent Values Used by theAtmospheric Oxidation Program, Version 1.30, November 1990 [Meylan (1990b)].

-37-Table 7. Group Rate Constants for OH Radical Addition to 1,2-Dialkene (Allene) Units1

Structure k 

### x 1o12 cm3tmolecule-sec CH2=C=CH- 31.0 -CH=C=CH- 57.0 CH2=C•C< 57.o2 -CH=C=C< 85.o2 >C=C=C< 110.o2

1 Data from Table 4 in Group Rate Constants and Substituent Values Used by the Atmospheric Oxidation Program, Version 1.30, November 1990 [Meylan (1990b)]. 2These values have been estimated••••the estimates are based upon analogy to the single unit olefin rate constants (see Table 2).

-38- 

# ....,.

## . Table 8. Substituent Factors [C(X)) for OH Radical Addition to Olefine and Acetylenes1 {values marked with "**" are estimated/assumed values) Substituent Factor
l. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31.-F -CL -Br -CH2CL 0.76 -eN -CHO -C{•O)CH3 -OCH3 •0 -I ** 0.26 -CH2Br ** -CH2!' ** -CH2I ** 

### -c-c ** not used -Phenyl ** -C(.O)X ** -oc ** 

### -c•c **


### -s ** 1.0 

### -o ** 1.0 -P ** 1.0 -N02 ** -ON02 ** •S ** 1.0 -N ** 0.6 •P ** 1.0 •N ** 1.0 cyclic

### c-o Miaainq R ** 0.4 0.20 0.26 0.15 0.26 0.91 1.3 1.0**{qi~en** same value as -Br) 0.76 {qiven same value as -CH2CL) 0.76 {qiven same value as -CH2CL) 0.76 {qiven same value as -CH2CL) 0.85 1.0 {Atkinson assumption, Int. J. Cham. Kinet. 19:822.) 0.91 {given same value as -C(•O)CH3 1.3 (given same value as -ocH3) 1.10 {baaed onexperimental rate constant for diacetylene) {arbitrarily aaaiqned a value of unity) {arbitrarily aaaiqned a value of unity) {arbitrarily assigned a value of unity) 0.5 (arbitrary estimate) 0.6 (arbitrary estimate) (arbitrarily aasiqned a value of unity) {arbitrary estimate) {arbitrarily assiqned a value of unity) {arbitrarily aaaiqned a value of unity) 0.20 {baaed on data for naphthaquinone) 1.0 1.00 {for an alkyl or a cycloalkyl qroup) Data from Table 7 inGroup Rate Constanta and Substituent Values Used by the Atmospheric Oxidation Proqram, Version 1.30, November 1990 [Meylan (1990b)). -39-Table 9. Electrophilic Substituent Factors for OH Radical Addition to Aromatic Rings1 (values marked with "**" are estimated/assumed values) The**~** and**~** values which are**~** considered "assumed" values are taken directly !romth.following reference: Brown, H.c. and Okamoto, Y (1958), "Electrophilic Substituent Constanta", J. Am. Chern. Soc. 80: 4979-4987. Various "assumed" values are baaed on similar structures with known a+ values.**~** 

# a;
1. Amino (-NH2) -0.16 -1.3 2. Dimethylamino (CH3-N-CH3) -0.16 ** -1.7 3. Aniline (C6H5-NH-) -0.16 ** -1.4 4. Acetylamino (CH3C(•O)-NH-) 0.21 ** -0.6 5. Benzoylamino (C6H5-C(=O)-NH-) 0.21 ** -0.6 6. Hydroxy (-OH) 0.121 ** -0.92 7. Methoxy (-OCH3) 0.047 

### -o.778 

### a. Phenoxy (C6H5-0-) 0.10 ** -0.50 9. Methylthio (CH3-S-) 0.158 -0.604 10. Methyl (CH3-) -0.066 

### -o.311 11. Ethyl (CH3-CH2-) -0.064 -0.295 12. Isopropyl (CH3-CH-CH3) -0.060 -0.280 13. tart-Butyl (-C(CH3)(CH3)(CH3)) -0.059 -0.256 14. Aromatic (phenyl) 0.109 -0.179 15. Chloromethyl (-CH2-CL) 0.14 -0.01 16. Fluoro (-F) 0.352 -0.073 17. Bromo (-Br) 0.405 0.150 18. Chloro (-CL) 0.399 0.114 19. Iodo (-I) 0.359 0.135 20. Trifluoro (-C-F3) 0.520 0.612 21. Cyano (-C&N) 0.562 0.659 22. Nitro (-N02) 0.674 0.790 23. Carboxy (-C(•O)-OH) 0.322 0.421 24. Carbomethoxy (-C(•O)-O-CH3) 0.368 0.489 25. Carboethoxy (-C(•O)-O-CH2-CH3) 0.366 0.482 26. Carbethoxymethyl (-CH2-C(•O)-O-CH2-CH3) -0.01 -0.164 27. Bromomethyl (-CH2-Br) 0.14 ** -0.01 ** 28. Iodomethyl (-CH2-I) 0.14 ** -0.01 ** 29. Nitrate (-ON02) 0.674 ** 0.790 ** 30. Olefinic (-C•C) 0.02 ** 0.02 ** 31. Acetylenic (-C•C) 0.21 ** 0.23 ** 32. -O-R (assume methoxy) 0.047 ** -0.778 ** 33. Phoaporua (-P) 

### o.o ** 0.0 ** 34. Sulfur (-S) (assume methylthio) 0.158 ** -0.604 ** 35. Carbonyl (-C•O) 0.10 ** 0.35 ** 36. Aldehyde (-CHO) 0.36 ** 0.22 ** 37. -C-CL3 0.55 ** 0.65 ** 38. -C-Br3 0.55 ** 0.65 ** 39. -C-I3 0.55 ** 0.65 ** 40. -CH2-F 0.10 ** -0.05 ** 41. -CH2- (assume ethyl) 0.06 ** -0.295 ** 42. -CH- (assume isopropyl) 0.06 ** -0.280 ** 43. -CH-Halogen (assume chloromethyl) 0.14 ** -0.01 ** 44. >C< (assume t-butyl) -0.059 ** -0.256 ** -40-**~** ,;. Table 9. continued**~** 

# a;

45. -NH- -0.16 ** -1.0 46. -N= -0.03 ** 0.15 47. -CH2-CN 0.17 ** 0.01 48. -N=N 0.30 ** 0.64 49. -0-C(•O)- 0.10 ** -0.10 

### so. Undefined 

### o.o ** 

### o.o 51. -o-P 0.10 ** -0.20 52. -S-CN 0.30 ** 0.25 53. 

### -s-co 0.20 ** 0.15 54. -o-Halogen 0.15 ** -0.10
For the SS-59, the Xrefers primarily to halogens, but the program also considers nitro and cyano groups. The estimated values are taken from Atkinson publications pertainingto estimated rata constants for PCBs.


### ss. -C6H4-Xl 0.25 ** 0.02 56. -C6H3-X2 0.39 ** 0.22 57. -C6H2-X3 0.53 ** 0.42 

### sa. -C6Hl-X4 0.67 ** 0.62 59. -Phanyl-XS 0.81 ** 0.82 60. -503 0.50 ** 0.50  **  **  

**  **  

**  **   **  ** 61. -S•O -0.16 ** -1.30 **

1 Data from Table 8 inGroup Rate Constanta and Substituent Values Used by the Atmospheric Oxidation Program, version 1.30, November 1990 [Meylan (1990b)].

-41-recommended that AOP adopt the group rate constant k(1, UNS CH) = o.ooo, list it in Table 1, and show it in all detailed calculations for H-atom abstraction from various unsaturated functional groups (=C-H). For the compound o,o-dimethyl chlorophosphorothioate, Atkinson et al. (1988) indicated that the group rate constant k(P-Cl) = o.oo; and this should be added to Table 1 and to the computer program. Furthermore, the group rate constants k(>NNO), k(>N-N02), and k[P(=O)] should be listed as o.oo. Inspection of the data inTable 1 indicates that k(-S-) = 2.05• This value is applicable to OH radical reaction in the presence of air at 1 atmosphere pressure and thus in the presence of oxygen. In the absence of oxygen, k(-S-) = 0.00 (Atkinson et al. (1988)]. These facts are pertinent sinceAOP incorrectly estimates koH for acyclic and cyclic sulfides and compares the estimated values with the experimental values6• For example, for dimethyl sulfide, the recommended experimental value of koH from Atkinson (1989) is 4.56, Table 24, which is valid in the absence of oxygen. Therefore, inthe data base for these compounds, the experimental value should be qualified to indicate that koH was
5 It should be noted that for convenience, the factor 1o-12cm3molecule-ls-1 has been omitted. In all subsequent discussions on group rate constants, this factor will be omitted. In addition, in all subsequent discussions, all rate constants k(i) for all individual reaction pathways and koH will be written without the factor 1o-12cm3molecule-1s-1. 6 From Meylan (1990b), page 10, "EstimationAccuracy of AOP vs. PCFAP."
-42-

## ..- obtained from measurements in the absence of oxygen. If one wants to compare the estimatedvalue with the experimental value, thenkoa should be estimatedunder the boundary condition in the absence of oxygen and koa

## =2.59 [sincek(-S-) 

## =O.OO]. Thus, a footnote should be added to the numerical value of the group rate constantk(-S-) inTable 1 [i.e., for k(-S-)]. The numerical value shouldbe (2.0)3 and the footnote 3 at the bottom of this table should be 3 Applicble at 298 Kand a total pressure of 1 atmosphere in air (andthus in the presence of oxygen). In the absence of air, and thus in the absence of oxygen, k(-S-) 

## =o.oo. This is discussed inmore detail in Section IV.E.1.b. From the experimentalkoa data of diethylhydroxylamine, it
was found thatk(>NOH) = 

### o.oo [Leifer (1991a)] and this group rate constant shouldbe entered intoTable 1 and in the AOP Computerprogram. InTable 1, it is indicated thatk(-SH) 

## =31 for RSH, where Ris an alkyl group. This group rate constant is not valid when R is an aromatic group, based on the experimental rate constant for thiophenol [Meylan (1990b)]. For thepresent, this assignment canbe tentativelyused. However, the experimental koH data from Barnes et al. (1986) may not be valid. Therefore,
more experimental data is needed on thiophenol and other alkyl and aromatic thiols to confirmthe assignment for k(-SH). In Table 1, the value of the group rate constantk(-OH) is only applicable to H-atom abstraction from thehydroxyl groups in alcohols and glycols and this fact must be noted in Table 1 for -43-k(-OH) and in the computer program. This group rate constant is not applicable to H-atom abstraction from the hydroxyl groups in carboxylic acids and alkyl peroxides. See Section IV.C.3.b. for the discussion of the estimation of k08 for carboxylic acids and Section IV.C.4.b. for the discussion of the estimation of k08 for alkyl peroxides. In Table 2, item, No. 57, should be changed to F(R2CHC1) = 0.57 (estimatedby Leifer from the experimental data of 2,3- dichlorobutane from Millet al. (1982); and an additional item F(R2CH- 1 Halogen 

### **) 

## =0.57 (based on the assignment in No. 57) should be added before item 60. The substituent factor F(-0-0 

### **) = 50 should be deleted from Table 2 because of the erroneous assumption that k(-OH) 

## = 0.036 for methyl and t-butyl hydroperoxide. For the details, see Section IV.C.4.b. Similarly, the substituent factor dimethyl sulfoxide, No. 58, Table 2, should be deleted since it is expected that the sulfoxidewould be readily oxidized to the sulfone. For the details, see Section IV.E.2.b. Table 4 lists the group rate constant for the functional group >C=C< as 110.0; it should be 110 based on the experimental koH data for 2,3-dimethyl-2-butene and the recommended value by Atkinson (1986,1989). Therefore, the last significant figure should be deleted. Similarly, the group rate constant for -C•Cin Table 6 should be 29 and not 29.0 based on the recommendation of Atkinson (1987, page 814).
-44- 

# -.

# .. "


### . In Table a, some of the substituent factors C(X) are marked with the symbol ** to indicate that they are based on estimated/ assumed values. However, if a substituent factor is based on experimental koH data, then the symbol ** should be omitted. For example, consider diacetylene, in Table a, No. 19; this substituent factor is listed as {C[-C•C-**]} = 1.10 (based on the experimental data for diacetylene). The entry in this table should be No. 19 C[-C•C-] = 1.10 (based on the experimental data of diacetylene). Similar comments are applicable to the substituent factors C(X) for numbers 29 and 16, Table a. Therefore, for the substituent factor C[Cyclic C=O **] (No. 29), the double asterisks should be removed since the value is based
on the experimental koH data of 1,4-naphthoquinone; similarly, for No. 16, C(phenyl **) = 1.0 should be C(phenyl) = 1.00, based
on the experimental koH data of styrene, a- and

**~-methyl** styrene, and P-dimethyl styrene [Atkinson (19a7, page a2a)]. These comments also apply to the substituent factors F(X) marked with ** inTable 2. In Table a, No. 14 is listed as C(C•C- **) = o.a5 without any notation as to how this value was derived. Since this represents an estimated/assumedvalue, a qualifying statement should be added to designate how this assignment was made. Finally, in Table 9, the

**a~** value for substituent -cH2- (No. 41) is listed as 0.06 ** by analogy with the ethyl group. However,

**a~** for the ethyl group is -0.064 and this value should be listed in No. 4, Table 9. -45-IV.B. some Comments on Hydroxyl Radical Addition to Heteroaromatic and Fused Polyaromatic Ring Systems Meylan (1990b) developed elegant S/R relationships for estimating the second-order rate constant for OH radical addition to heteroaromatic (mono and fused polycyclic) rings and to fused polynuclear aromatic hydrocarbon (PAH) rings. For monocyclic heteroaromatic compounds (ar'), AOP uses equation 24; for fused ringpolynuclear aromatic hydrocarbon compounds (PAH), AOP uses equation 29; and for fused ringpolynuclearheterocyclic
I compounds (PAH ), AOP uses equation 30. The first term in each of these equations 

### [i.e., Ai, Bi, and Bi, respectively] was derived byMeylan from: (1) the experimental values of koH for the basic, or parent, heterocyclic ring or the fused polynuclear aromatic hydrocarbon ring structure; or from (2) the experimental ionizationpotentials for the parent fused ring polynuclear aromatic hydrocarbons and fused ringpolynuclearheteroaromatic compounds. Tables 10 and 11 list the values of Ai and Bi, respectively, for various heteroaromatic ring structures and polyaromatichydrocarbons derived from the experimental koH data for the parent aromatic compounds. Tables 12 and 13 list the values of Bi and

# ai, respectively, derived from the experimental ionizationpotentials of the parent ring compounds. AOP has a SMILES interpreter which allows itto identify the parent aromatic ring structure and assign it the appropriate 

### ' value of Ai, Bi, or Bi

. AOP then adjusts this value for any substituent on the ring by utilizing the appropriate substituent -46-Table 10. Experimental Values of Ai for Some Monocyclic Heteroaromatic Compounds*
Heterocyclic Aromatic Ring Structure Pyrrole Fur an Thiofuran Imidazole oxazole Thiazole Pyridine 1,3,5-Triazine Experimental Value of Ai {1o-12cm3molecule-1s-1)
110.0

40.5

9.53 36.0

9.1 1.4 0.37 0.15

* Data from page 7 of the User's Guide for the Atmospheric Oxidation Program, Version 1.10, November 1, 1990 [Meylan (1990b)].

-47-Table 11. Experimental Values of Bi for Some Polynuclear Aromatic Compounds*
PolynuclearAromatic Rinq Structure Naphthalene Anthracene Phenanthrene Experimental Value of Bi (1o-12cm3molecule-1s-1) 21.6 110.0

31.0

* Data from paqe 7 of the User's Guide for the Atmospheric oxidation Proqram, ·version 1.10, November 1, 1990 [Meylan (1990b)].

-48-Table 12. Values of Bi for Polynuclear Aromatic Hydrocarbon Structures Derived from ExperimentallyMeasured Ionization Potentials*

Polynuclear Aromatic Ring Structure
4 Fused Benzene Rings 5 Fused Benzene Rings 6 Fused Benzene Rings Assigned Value of Bi Based on the ExperimentallyMeasured Ionization Potential (1o-12cm3molecule-1s-1)
80.0 150.0 200.0

* Data from page 7 of the User's Guide for the Atmospheric Oxidation Program, Version 1.10, November 1, 1990 [Meylan (1990b)].

-49-Table 13. Values of Bi for Polynuclear Heteroaromatic Structures Derived from Experimentally Measured Ionization Potentials*

I Assigned Value of Bi Based on the ExperimentallyMeasured Ionization Potential (1o-12cm3molecule-1s-1) Polynuclear Heteroaromatic structure Quinoline Isoquinoline Quinoxaline Quinazoline Acridine 6.5 6.5 2.0 2.0 27.5

* Data from page 7 of the User's Guide for the Atmospheric Oxidation Program, Version 1.10, November 1, 1990 [Meylan (1990b)].

-so- -...

## ..-

factors

**a~** and

**a~** for the substituents on the ring. For example, for 1-chloronaphthalene, the·SMILES interpreter in AOP identifies the parent naphthalene ring and selects the value of Ai for this ring. AOP then adjusts this value by considering the effect of the chlorine substituent on the reactivity of the ring.It shouldbe noted thatMeylan did not develop S/R relationships for fused ring aromatic compounds containing five membered heterocyclic rings. For example, AOP cannot estimate k08 for benzothiazole. Inprinciple, however, the basic concepts of Meylan can be used. For example, if k08 is measured for benzothiazole, then Bi from equation 30 can be determined. Therefore, with this value of Bi, k08 can be estimated for substitutedbenzothiazoles utilizing the appropriate substituent factors a+ mand a+ p for the substituents
on the ring. More experimental k08 data is needed on a number of additional derivatives of these heteroaromatic 

### ' (ar ) , polynuclear aromatic hydrocarbons (PAH), and polynuclear heteroaromatic ring (PAH') structures to confirmthe S/Rrelationships of Meylan (1990b) [i.e., confirmthe validity of equations 24, 29, and 30]. It shouldbe noted that inTables 10, 11, and 12, AOP lists
a few of the values of Ai and Bi to four significant figures. At best, the experimental data used to derive these constants are only valid to three significant figures. Therefore, it is

-51-recommended that the values of Ai and Bi for pyrrole, anthracene, and for 4, 5, and 6 fused benzene rings should be listed to three significant figures. IV.c. H-Atom Abstraction from C-H and -OH Groups by Hydroxyl Radicals IV.C.1. saturatedAlkanes IV.C.1.a. Evaluation of the Experimental koH Data Tables 14.A. and 14.B. summarize the pertinent experimental koH data at 298 Kfor the reaction of OH radicals-with acyclic and cyclic alkanes, respectively, as obtained from AOP and the literature. For this class of compounds, hydroxyl radical reaction only involves the abstraction of H-atoms from the various primary, secondary, or tertiary C-H groups. The first column inthese two tables lists the name of each alkane; the second column liststhe experimental value of koH at 298 KinAOP [Meylan (1990b)] and is labeled Experimental/AOP; the third column lists koH at 298 Kas obtained by Leifer from Atkinson (1989) and/or from the literature and is labeled Experimental/(a); the fourth column lists the estimated value of koH at 298 Kas obtained from AOP and is labeled Estimated/AOP; and finally the fifth column lists the estimated, hand calculated (HC), value of koH at 298 Kas obtained by Leifer using the S/R relationships of Atkinson and is labeled Estimated/HC. Atkinson (1989) critically analyzed the available experimental koH data and recommended the best values along with the rationale behind each recommendation and the uncertainty for -52-Table 14.A. Comparison of the EstimatedValues of koH at 298 Kfor Saturated Acyclic Alkanes from the Atmospheric Oxidation Computer Program (AOP) and from a Hand Calculation (HC) and the Experimental koa Data Reported in the Literature Versus the Experimental koa Data Reported inAOP 1o12koH(cm3molecule-1s-1) 

# I Chemical Experimental Estimated AOP (a) AOP HC Methane 9-t/-8,;:;-11 0.00841 0.00836* 0.00841b (c) Ethane ?'-1-'?L/-0 0.268 0.268* 0.288 0.288 Propane 7

### Lf.<:j'?

**~** 1.15 1.15* 1.21 1.21 n-Butane

**/0~-** 97··

### s:=' 2.54 2.54* 2.53 2.53 2-Methylpropane 1S-;)..g-s- 2.34 2.34* 2.39 2.39 n-Pentane I09-Co0-0 3.94 3.94* 3.93 3.93 2-Methylbutane ::;15-'ifff

### -f-j 3.90 3.9* 4.00 4.00 2,2-Dimethylpropane'/b3-K2-J 0.849 0.849* 0.743 0.743 n-Hexane 110-S'-/-3 5.61 5.61* 5.32 5.32 2-Methylpentane IO"f-1]3-$"' 5.60 5.6* 5.39 5.39 3-Methylpentane

**CJ~-ILj-** 0 5.70 5.7* 5.77 5.77 2,2-Dimethylbutane15-83-2. 2.32 2.32* 1.82 1.83 2,3-Dimethylbutane

### 1'1-

**;;lC}-~** 6.20 6.2* 5.46 5.46 n-Heptane 1'1-:J-

**~;2**

# -s 7.15 7.15* 6.72 6.71 2,2-Dimethylpentane

### S'JO-

**.3S-~** 3.37 3.37d 3.22 3.22 2,4-Dimethylpentane;o6'-o8-"f- 5.16 5.16d' 6.86 6.85 2,2,**3-Trimethylbutane~~- 0~-2..**  4.23 4.23* 3.29 3.30 n-octane

**/1/-~5**-, 8.68 8.68* 8.11 8.11 2,2-Dimethylhexane

### 590-73-S' 4.83 4.83d 4.61 4.61 2,2,4-Trimethylpentane5'-/o-8Lj-l 3.6, 3.68* 4.68 4.68 2,3,4-Trimethylpentane 7.0 6.97e 8.70 8.70 SfoS-15-3 '

**~** j I

-53-Table 14.A. continued 1o12koH(cm3molecule-1s-1) Chemical Experimental Estimated 

### 5'14- g

### d.-1 csHl'i?



# ~I AOP (a) AOP 2,2,3,3-Tetramethylbutane 1.08 1.08* 1.11 n-Nonane Ill-f{t.j-;J.. 10.20 10.2* 9.51 2-Methyloctane 3;Jc;J

**J-~1-;;..** 10.1 10.1d 9.58 4-Methyloctane

**;):JJ~-** 

### 31-'1 9.72 9.72d 9.95 2,3,5-Trimethylhexane

**/u~~-o3-0** 7.88 7.88d 10.1 n-Decane /;}'-/-

**If?-~** 11.6 11.6* 10.9 n-Undecane /!d.O-d)/

### -J.j CllH

## jq 13.2 13.2* 12.3 n-Dodecane JJ()- Ljo-

### 3 14.2 14.2* 13.7 n-Tridecane 

### &9-9-So-s- 16.0 16* 15.1 n-Tetradecane

**~,JCj-** 59-

# i 19.2 19.2* 16.5 n-Pentadecane

**~~9- c.:,~** 

## -cp 22.2 22.2f 17.9 n-Hexadecane 

### 5tf1-'ftJ- 

### 3 24.9 24.9f 19.3

a Experimental values from Atkinson (1989) and the literature. b Estimatedvalue is based on the measured value. c Cannot be estimatedby the S/Rmethods of Atkinson. d Experimental value from Behnke et al. (1988). d' Experimental value from Atkinson et al. (1984).

e Experimental value from Harris and Kerr (1988). f Experimental value from Nolting et al. (1988).

-54- HC 1.11 9.50 9.58 9.95

- 10.1 10.9 12.3 13.7 15.0 16.5 17.9 19.3•Table 14.B. Comparison of the EstimatedValues of koH at 298 Kfor Saturated Cyclic Alkanes from the Atmospheric Oxidation Computer Program (AOP) and from a Hand Calculation (HC) and the Experimental koH Data Reported in the Literature Versus the Experimental koH Data Reported in AOP - 1

**~** I ( 0 

## " ..( I ( ..$)



### ~ 1o12koH(cm3molecule-1s-1) Chemical Experimental Estimated AOP (a) AOP HC cyclopropane

**9~- /~-**  Lj 0.07 0.071b 0.0711 0.0711 .i-PropylcyclopropaneU1fo-

### ;;9::

## r 2.84 2.84c 2.85 2.85 c •'If<t&> 1.2d Cyclobutane r!)

## &>1--23-D 1.20 1.23 1.23 cyclopentane [)8

### 7-

**~;)._-** 3 5.16 5.16* 5.58 5.58 Cyclohexane IIO-Ba.--=f" 7.49 7.49* 8.37 8.37 Methylcyclohexane 1

### o

**~**-g

### 7-

**~** 10.4 10.4e 10.2 10.2 1,1,3-Trimethylcyclohexane 3 8.73 8.73f 9.18 9.18 30f'O-(t?&:,- 12.5g Cycloheptane

**~4/-t,I./-S'** 12.5 9.76 9.77 cyclooctane d-'J;)-V;Lf-&> 13.7 13.7h 11.2 11.2 Bicyclo [2.2.1] heptane219-23-2 5.49 5.49i 9.49 9.49 Bicyclo [2.2.2] octanez&-o-33-1 14.7 14.7i 16.2 16.2 Bicyclo [3.3.0]

**octane~9£,-** 'l.l-1 11.0 11.oi 10.4 10.4 $Pii 17.2i ili-Bicyclo [4.3.0] nonane 17.2 14.1 14.1 trans-Bicyclo [4.3.0] nonane 17.6 17.6i 14.1 14.1 £1a-Bicyclo [4.4.0] decane 19.9 19.9i 19.0 19.0

**t/9~-**

# OI-l Uo/-itS" 20.4i trans-Bicyclo 4.4.0] decane 20.4 19.0 19.0 L{q_3-

### ?f-'1 ctui-PS, 11.3i Tricyclo [5.2••

### ou] decane 11.3 12.3 12.3 r;

### oa..;-3!S-,..< ool-l;;._. 22.6j Tricycle [3.3.1.1

**~]** decane 22.6 24.1 24.1 .;73/-"'3-co< C/ofll&
a Experimental values from Atkinson (1989) and the literature. b Average value from the experimental data of Zetzsch (1980) and Jolly et al. (1983). c Experimental value from Atkinson and Aschmann (1988). d Experimental value from Gorse and Volman (1974). e Experimental value from Atkinson et al. (1984). f Experimental value from Behnke et al. (1988) as reported in Atkinson (1989). g Average value of the experimental data of Zetzsch (1980) and Jolly et al. (1985). h Experimental value from Behnke et al. (1988) as reported in Atkinson (1989)• i Experimental value from Atkinson, Aschmann, carter (1983a). j Average value from the experimental data of Atkinson, Aschmann, and Carter (1983a) and Behnke et al. (1988). * Recommended value by Atkinson (1989) with the rationale for the recommendation, and the uncertainty for the recommendation.
-55-each recommendation. These recommended values have an asterisk after each value. In general, the experimental values of k08 listed inAOP are the same as those obtainedby Leifer; there are, however, a few differences. Formethane, the recommended Atkinson value is 0.00836* whileAOP lists 0.00841. For 2,3,4-trimethylpentane, thekoH value of 6.97 was obtainedby extrapolation of the data and Kerr (1988) and appears to be the best value. The best value of k08 for cyclopropane should be 0.071 as obtained by averaging the data of Zetzsch (1980) and Jolly et al. (1985) rather than the value of 0.07 listed inAOP. For a few compounds, the incorrect number of significant figures was cited by AOP; the recommended values list two significant figures whereas AOP lists three significant figures. For example, for 2-methylbutane, the Atkinson recommended value is 3.9* whileAOP lists 3.90. For cyclobutane, the value of koH reported by Gorse and Volman (1974) andAtkinson (1989) is 1.2 and not 1.20 as listed inAOP. The experimental koH data of Gorse andVolman is only good to two significant figures. It shouldbe noted that the names of two tricyclic decanes {tricycle [5.2.1.0] decane and tricycle [3.3.1.1] decane} entered inAOP are incorrect. The correct names should be tricycle (5.2.1.0 2•6] and tricycle (3.3.1.1 3•7] decane since the superscript numbers on the last digitmust be specifiedto identifythe bridgehead carbons on the last ring. Finally, the
-56- > ..

# -

# . name of methylcyclohexane is the correct name and not 1-methylcyclohexane as listed inAOP. IV.C.1.b. Evaluation of the Estimated koH Data Apreliminary evaluation of the AOP computer program (Meylan (1990a)) in July 1990 indicated that for some bicyclic and tricyclic alkanes, themethod of estimatingkoa inAOP was incorrect. The AOP computer programdid not use the ring strain factors [F(J), F(4), F(S), or inMeylan's notation RSJ, RS4, RSS) correctly in the calculations. The discrepancies were discussed withMeylan byphone.and a set of the calculations were sent to him for evaluation. As a result, Meylan (1990b) revised the AOP computer program for these types of compounds to accurately reflect theAtkinson S/Rrelationships for strained ring compounds [Version 1.30, November 1, 1990]. In evaluating the estimatedvalues of koa by AOP and HC, a few comments can bemade about the number of significant figures used. In general, the summary table inAOP lists the estimated koawith a maximum of six significant figures and the detailed calculations listk(1a) ork(1c) with a maximum of five significant figures. However, the group rate constants

**k~, k~,**  and

**k~,** [orkprim' ksec' and ktert inMeylan's notation] and the substituent factors F(CH3-), F(-CH2-), and F(>C<) are, at best, known to three significant figures. Therefore, it is recommended thatAOP show the detailed calculations with four significant figures and listk(1a) ork(1c), ork(1a) + k(1c), and koa in the
-57-summary table rounded off to 3 significant figures. These comments on the use of an excessive number of significant figures apply to all classes of chemicals and specific chemicals. Comparison of the estimated values of koH from AOP with those from HC (after rounding off all estimated values to three significant figures) inthe last two columns in Tables 14.A. and 14.B. indicates that, except for methane, the values are essentially the same. The trivial differences in the last digit
are due to the method of rounding off the last digit in HC. For methane, AOP lists a value of 0.00841 which is the experimental value [which really should be 0.00836* as recommended by Atkinson] whereas HC does not list a value; koH cannot be estimated by the S/Rrelationships of Atkinson for this compound. The number of significant figures for RS3, RS4, and RSS for strained rings is incorrect. For example, for cyclobutane, RS4 

## = 0.22000 is used in the detailed calculation section. However, for RS4, Atkinson listed it as 0.22. The detailed calculations for H-atom abstraction are somewhat confusingwhen the ring strain factor is used. For example, for bicyclo [2.2.1] heptane, AOP gives ksec • 0.838 F{-CH2-)F{>CH-)(RSS)(RSS)

- 0.838(1.29){1.29)(0.64)

- 0.892 It seems tome that a more consistent notation for RSS would be (RS5)2 • (0.80)2 rather than {RSS)(RSS) = 0.64. Therefore, ksec


### -sa-should read

or ksec.= 0.838 F(-CH2-)F(>CH-)(RS5)2
= 0.838 (1.29) (1.29)(0.80)2
= 0.892

ksec • 0.838 F(-CH2-)F(>CH-)(RS5)(RS5)
= 0.838(1.29)(1.29)(0.80)(0.80)

= 0.892 IV.C.2. Haloalkanes IV.C.2.a. Evaluation of the Experimental koH Data Table 15 summarizes the pertinent experimental koH data at 298 Kfor the reaction of OH radicals with haloalkanes as reported inAOP, inAtkinson (1989), and in the literature. In general, the literature values listed in the column Experimentalf(a) are the same as those in the column Experimental/AOP; there are, however, some differences. For 1,1,1-trifluoroethane, AOP lists a value of 0.017, a ten-fold higher value than the correct value of 0.00171 from Martin and Paraskevopoulos (1983) and Atkinson (1989). [Please note that these values are listed in the units 1o-12cm3molecule-1s-1 rather than 1o-14cm3molecule-1s-1 as listed in Table 15; see footnote 5, page 42.] For 1,1,2-trichloroethane, the extrapolated value from the data of Jeong and Kaufmann (1979) and Jeong et al. (1984) obtained by Leifer is 0.324 while AOP lists a value of 0.328. For three haloalkanes, AOP does not list an experimental value -59-Table 15. Comparison of the Estimated Values of koH at 298 Kfor Haloalkanes

**-~** from the Atmospheric Oxidaticn Computer Program (AOP) and from a Hand Calculation (HC) and the Experimental kQH Data Reported in the Literature Versus the Experimental koH Data

**~n** AOP
1o14koH(cm3molecule-1s-1) 

# / Chemical Experimental Estimated AOP (a) AOP HC Fluoromethane

### S93-S3-

**~** 1.68 1.68* 1.43 1.43 Chloromethane

**11~~1-3** 4.36 4.36* 5.47 5.47 Bromomethane

**?4-83-~** 4.02 4.02* 4.32 4.32 Difluoromethane

### 15-;o-s- 1.09 1.09* 0.82 0.821 Fluorochloromethane

**5~3-ro-1** 4.41 4.41* 3.15 3.15 Dichloromethane

**~~-09~~** 14.2 14.2* 12.1 12.1 Trifluoromethane

### 15"

### -4&-r 0.024 0.024b 0.18 0.178 Difluorochloromethane1-S'

**~5"-62** 0.468 0.468* 0.682 0.682 Fluorodichloromethane

### 15""-

### J/?ri 3.03 3.03* 2.62 2.62 Tr!chloromethane

## u"1
-

**~**-

### 3 10.3 10.3* 10.0 10.0 Fluoroethane

### 35 3-.%-<o 23.2 23.2° 20.5 20.5 Chloroethane 

### 1S

### -oo-3 39 39* 40.1 40.0 1,1-Difluoroethane 15-3-=J-u, 3.4 3.4* 3.23 3.23 1,2-Difluoroethane&J

### Lj

...

**7~**-&; 11.2 11.2d 14.1 14.1 1,

**1-Dichloroethan~ys-** 

## :3L/-3 26 26.oe 34.6 34.6 1,2-Dichloroethane I0r-Ob-cJ 22 22.oe 36.3 36.3 1,2-Dibromoethane

### lot.,-93-1- 25 25.oe 28.7 28.7

**1,1,1-Trifluoroethane~~o~~-~** 1.7 0.171d 1.08 1.08 1, 1,1-Trichloroethane

### 11-SS-(., 1.19 1.19* 1.30 1.30 1,1-Difluoro-1-chloroethane 0.358 0.358* 0.36 0.360

**~s-CP;t-.3** 1.83d 1, 1,2-Trifluoroe nane 1Jo-h6-o 1.8 2.35 2.35 1,1,2-Trichloroethane

### ::JC)-

### oo-s- 32.8 32.4f 33.2 33.3 1,1,1,2-Tetrafluoroethane 0.854 0.854* 0.62 0.622 8//-

**9~-d.** 1-Chloro-2,2,2-Trifluoro- 1.62 1.62* 2.39 2.39 ethane 

### -:rs-'8;8-

## r 1,1,2,2-Tetrafluoroethane (j) 0.679 0.36 0.359 

### 359-3s-3

-60-) "
• Table 15. Continued 1o14koH(cm3molecule-1s-1) Chemical Experimental Estimated



# ~ AOP (a) AOP HC Pentafluoroethane35'1-.33-& **(.~I/**

### Fs- 0.25 0.249d 0.13 0.135 1-Chloro-1,2,2,2-Tetrafluoroethane 1.02 1.02* 0.52 0.516

**OJ83~ ~!j;9-0**  **C~I-/C)**Ff 3.35 3.35* 1.98 1.98 1,1-0ichloro- 12,2-Trifluoroethane 3oeo-g3-,;1. c;JI-fCf:2F3 43.5k **1,2-0ibromo-3-chloropropane~-/~-g** 44 50.3 50.3 2-Chlorobutane

### =/8-8b-"L/ (..31-+5

**Bli';~**CJL (j) 230i 164 164 2,3-0ichlorobutane15'8J-

### 91-1- (j) 96i 95.7 95.7

a Experimental values from Atkinson (1989) and the literature. b Since the experimental data was obtained at temperatures

**~** 387 K, the value at 298 Kshouldbe usedwith caution [Atkinson (1989)]. c Experimental value from Nip et al. (1979). d Experimental value from Martin and Paraskevapoulos (1983). e Experimental value from Howard and Evenson (1976). f Extrapolated from the experimental data of Jeong and Karfmann (1979) and Jeong et al. (1984). g Extrapolated from the experimental data of Clyne and Holt (1979). h Experimental value from Tuazon et al. (1986). i Experimental value from Millet al. (1982). j No experimental value given in the AOP data base. * Recommended value byAtkinson (1989) with the rationale for the recommendation, and the uncertainty for the recommendation.

-61-{i.e., for 1,1,2,2- tetrafluoroethane, 2-chlorobutane, and 2,3- dichlorobutane). For six compounds, the literature values have three significant figures while AOP lists two significant figures (e.g., for 1,1-dichloroethane, the literature value of Howard and Evenson (1976) is 0.260 while AOP lists 0.26]. IV.C.2.b. Evaluation of the Estimated koH Data Acomparison of the estimatedvalues of koH by AOP with HC inTable 15 indicates that they are essentially the same. The only differences beingthat in a few cases, AOP rounds off the estimated values to two significant figures. The estimated values of koH are good to three significant figures. For example, for trifluoromethane, the estimated value of koH by HC is 0.178, while AOP rounds it off to 0.18. IV.C.J. Carbonyl Compounds IV.c.J.a. Evaluation of the Experimental koH Data Table 16 summarizes thepertinent experimental koH data at 298 Kfor the reaction of OH radicals with 57 carbonyl compounds as reported in AOP, inAtkinson {1989), and in the literature. These carbonyl compounds can be divided into several classes of compounds: 11 aldehydes, 19 ketones, 3 a-dicarbonyls, 1 acyl halide, 18 esters, and 5 carboxylic acids. First, consider all the compounds except the carboxylic acids. In these classes of compounds, 12 of them listedbyAOP had experimental koH data with two significant figures. If the original literature sources andAtkinson {1989) are checked, all the koH data are listed with three significant figures (e.g., formal, 3-hexanone, n-butyl -62-• ,,

Table 16. Comparison of the Estimated Values of k08 at 298 K for Carbonyl Compounds from the Atmospheric Oxidation Computer Program (AOP) and from a Hand Calculation (HC) and the Experimental kQH Data Reported in the Literature Versus the Experimental k08 Data**~n** AOP
1o12kou(cm3molecule-1s-1) Chemical**Class/Chem~l** Experimental Estimated AOP (a) AOP(%Error)0 HC A. ALDEHYDES Formal

### so-oo-o 9.7 9.77* 7.37 7.37 Ethanal

## ·?s-o'1-0 15.8 15.8* 16.2 16.2 Propanal ;2?r38-& 19.6 19.6* 22.0 22.0 Butanal iJ3- (.2-? 23.5 23.5* 25.5 25.5 2-Methyl Propanal**16-~~-~** 26.3 26.3* 23.4 23.4 Pentanal 110-&,')-_3 28.5 28.5* 27.6 27.6 3-Methylbutanal

### sqo-**~b-** 3 27.4 27.4* 30.0 30.0 2,2-Dimethylpropanalt.:b-/9

### -J 26.5 26.5* 22.7 22.7 Trichloroacetaldehyde**1ji-~?-w** 1.73 1.73a' 1.45 1.45 Hydroxyethanal I'/I-·-9'<::,**~?f** 9.9 9.9b 23.0 23.0 (Glycolaldehyde) Pentane-1,5-DialII1-3o-e' 23.8 23.8c 46.9 46.9
B. ACYCLIC KETONES Propanone &**?-u~l-** I 0.226 0.226* 0.219 0.219 2-Butanone 78-'j,3-_'3 1.15 1.15* 1.38 1.38 2-Pentanone 

### /u-:;-s-J-9 4.9 4.9* 4.80 4.81 3-Pentanone 

### 9(.,-cx7:)--tJ 2.0 2.0* 2.54 2.55 2-Hexanone !;C)J-**-=f8-~** 9.1 9.1* 6.95 6.96 3-Hexanone589-38-fi' 6.9 6.9od 5.97 5.97 4-Methyl-2-pentanone/'-1/-79-j- 14.1 14.1* 9.35 9.35 3,3-Dimethyl-2-butanone

### ls-q:r-<J 1.21 1.21e 2.01 2.01 2-Heptanone**l!o-~3-o** 8.67 8.67e 8.35 8.35

-63-Table 16. Continued



### Chemical

## Class/C~ical Experimental AOP 

### VI**505-go~o** 2,4-Dimethyl-3-pentanone 5.38 2-octanone JI/-

### I3
-

## 'f 1

### o•o 2-Nonanone**8~}-** 55-(a 12.2 2,6-Dimethyl-4-heptanona'CB'-&}-8' 27.5 2-Decanone**~**93--SL/-cp 13.2 2,4-Pentanedione**/~**

### 3-5

## ¥-eo 1.15 2,5-Hexanedione 

### 110-13-1 7.13 C. CYCLIC KETONES cyclobutanone 1 /c."JI-c:JS-**~** cyclopentanone/GJo-

### 9rJ--3 Cyclohexanone

### /08- 

### c::J'f-

### 1
D. a-DICARBONYLS Glyoxal 1o

## 1- ,.J;J-,::;.., Methylglyoxal**7~- ':1~-'?**  Biacetyl L/-31-

### 03-8 E. ACYL CHLORIDES Acetyl chloride

### 75-3(o-

# sF. ESTERS Methyl formate 

### /OT-31-3 0.87 2.94 6.39

11.4 17.2

0.238

0.068

0.23

-64- (a) 5.38d 11.0e 12.2e 27.5* 13.2e

1.15f 7.13f

11.4* 17.2*

0.238*

0.0689 Estimated AOP(%Error)0 HC 5.32 9.74 11.1 18.5 12.5

0.703 5.82

1.17 8.92 12.6

24.5 12.3

0.219

0.0720

0.216 5.31 9.74 11.1 18.5 12.5

0.703 5.82

1.17 8.92 12.6

24.5 12.3

0.219

0.0720

0.216Table 16. Continued

Chemical

**C~~/Chemical** Ethyl formate 

## /09-9L/-'f n-Propyl formate 1/Q-

### =fl../-7- n-Butyl formate

**5~£).**

### -8£j-

# r Methyl acetate

**-=f~-t..o-0;** Ethyl acetate lt../J-78-0 n-Propyl acetate tcf1-(o0-4 i-Propyl acetate 

### Io?J-.:1._

## 1-'-/ n-Butyl acetate f(}.3-Bfo-l.j .§l-Butyl acetate 

### ;os-'-fto-4 Ethyl propionate

### ICJ5-

### 3

# r3 n-Propyl propionate

**101-1-3~-S** Methyl butyrate(.p&3-

### tp-

# rEthyl buty,frate loS-

### 5'-/-i-- n-Propyl butyrate

**/o5-tato-~** n-Butyl butyrate 

### f'oiJ-

**~**

### )-

## qEthoxyethyl acetate;//-;S-9 Methyl trifluoroacetate 

### '-/31-tJ--=t-0 G. CARBOXYLIC ACIDS Formic acid

**~-18-~** Acetic acid 

### &'-/-/9

### -1- Propionic acid 

### -::f9-o9-1 n-Butyric acid 

## /61--9'2-:-((, i-Butyric acid ':fC}-

### 3/- 2..._ Experimental AOP

1.0 2.4 3.1 0.34 1.6 3.4 3.4 4.2 (n)

2.1 4.0 3.0 4.9 7.4 10.6 13.0

0.05

0.45 0.74 1.22 2.4 2.00 (a) 1.02h 2.38h 3.12h 0.341i 1.6* 3.4* 3.4* 4.2* 5.5* 2.14i 4.02h 3.04h 4.94h 7.41h 10.6h 13h' 0.052h

0.45* 0.741 1.221 2.4m 

### 2.ool Estimated AOP(%Error)0 1.44 2.89 4.28 0.216 1.44 2.89 3.12 4.28 4.99 1.63 3.08 1.48 2.71 4.16 5.55 14.0

0.216

0.436j(-3) 0.145(-80) 0.859(-30) 2.12(-12) 1.80(-10) HC 1.44 2.89 4.28 0.216 1.44 2.89 3.12 4.28 4.99 1.63 3.07 1.48 2.71 4.16 5.55 14.0

0.0518

(k) (k) (k) (k) (k)

a Experimental values from Atkinson (1989) and the literature. a'
. Exper1mental value from Nelson et al. (1984) as reported by Atkinson (1989).

-65-Table 16. continued b Experimental value from Niki et al. (1987) c Experimental data from Rogers (1989). This value of koa represents the average value of 25.2 and 22.4x1o-12cm3molecule-1s-1 as measured with the reference compounds propene and trans-2-butene, respectively. d Experimental value from Atkinson et al. (1982). e Experimental value fromWallington and Kurylo (1987). f Experimental value from Dagaut et al. (1988). g Experimental value from Atkinson (1987). h,Experimental value fromWallington et al. (1988). h Experimental data from Hartmann et al. (1986, 1987) as reported byAtkinson (1989). i Experimental value fromWallington et al. (1988). The data from campbell and

**Par~inson** (1978) was not used since the experimental method was probably

. not valid/Atkinson (1989)]. J Estimatedby [Meylan (1990b)] assuming that k(HCOOH 

### **) was 0.400. k Atkinson did not develop S/Rrelationships for carboxylic acids. 1 Experimental value from Dagaut et al. (1988b). The rate data of Zetzsch and Stuhl (1981) as reported inAtkinson (1989) is subject to significant uncertainties; hence it should not be used [Atkinson (1989)]. mExperimental value from zetzsch and stuhl (1981) as reported inAtkinson (1989). This value is subject to significant uncertainties andmust be used with extreme caution [Atkinson (1989)]. n No experimental value is given in theAOP data base. Avalue of 5.5x1o-12cm3molecule-1s-1 is given in the document "EstimatedAccuracy of AOP versus PCFAP. o Based on the experimental values ofkoij listed in column Experimentalf(a). 

### *Recommended value byAtkinson (1989) w1th the rationale for the recommendation, and the uncertainty for the recommendation.

-66-formate, methyl butyrate). For ethoxyethyl acetate, AOP lists the experimental value of koH with three significant figures while Atkinson (1989) and Hartmann et al. (1986, 1987) list it with two significant figures. For 2-octanone, AOP lists a value of koH of 10.0 whileWallington and Kurylo (1987) and Atkinson (1989) list a value of 11.0. For §-butyl acetate, AOP does not list a value inthe data base; from the document "Estimated accuracy ofAOP versus PCFAP, AOP does list a value of 5.5 for this compound. The recommended value by Atkinson (1989) is 5.5*. Experimental koH data listed inTable 16G. are available for

a few alkyl carboxylic acids---formic, acetic, propionic, and 

## n- andi-butyric acids as obtained from Atkinson (1989) and the literature. The koH data from Zetzsch and Stuhl (1981) for acetic, propionic, andn-butyric acids hadvery large uncertainties since the vapor pressures of these compounds were unknown. Hence, these data should not be used [Atkinson (1989)]. The experimental koH data for acetic, propionic, and i-butyric acids were obtained from a single source (Dagaut et al. (1988)]; hence, these data shouldbeused with caution until additional koH data are obtained from other researchers to corroborate the assignments. It shouldbe noted that for the aldehydes, the incorrect
names are used in theAOP data base. Since, the aldehyde functional group can only be at the end of the alkyl chain, there is no need to specify itspositionwith a number.

-67-IV.C.J.b. Evaluation of the Estimated koH Data Acomparison of the estimated values of koH reported by AOP with those from HC inTable 16 indicate that they are essentially the same except for methyl trifluoroacetate and the carboxylic acids. Formost of these compounds, the differences are trivial and are due to the method of rounding off the third significant figure. Formethyl trifluoroacetate, the estimated value of koH

**i~** AOP is 0.216 in contrast to the estimated value of 0.0518 in HC from Leifer. The apparent error is due to the effect of the very electrophilic

**g~oup** -cF3 on the substituent factor F[-OC(O)R]. Leifer (1991a) derived a substitutent factor F(-OC(O)CFJ] = 0.36 (31) which gives an estimated value of 0.0518. Therefore, it is recommended that the substituent factor listed in 31 be used in theAOP computer program and in Table 2. There are problems with the S/Rrelationships of Meylan (1990b) for the class of carboxylic acid compounds which will be described in the following paragraphs. For the alkyl carboxylic acids, Atkinson did not develop S/R relationships whileMeylan (1990b), inAOP, did develop S/R relationships. For these compounds, two reaction pathways were postulatedbyMeylan: H-atom abstraction from an alkyl group and H-atom abstraction from the OH group. Therefore, for these two reaction pathways,
-68-R(=O)OH + ·OH k(1) = k(1a) I ·R C(=O)OH + HOH (32)
RC(=O)OH + ·OH k(2) = k(-OH) RC(=O)O· + HOH (33)
where R' is an alkyl free radical [i.e., ·R' or for formic acid, it is ·C(=O)OH]. The overall rate of reaction with hydroxyl radicals is then koH = k(1) + k(2) = k(1a) + k(-OH) (34)
andMeylan assumed that reactionpathway 32 was the dominant pathway [i.e., k(1a) > k(-OH)]. Therefore, Meylan used the group rate constant k(-OH) = 0.036, derived from the alcohols; and the rate constantk(1a), for H-atom abstraction from the alkyl group, was calculated in the standardmanner using the S/R relationship of Atkinson. These results were thenused in equation 34 to calculatekoH· For formic acid, Meylan (1990b) assumed that k(1a) = k[HC(=O)OH 

## ** ] = 0.400 (35)

so that koH (formic acid, estimated) = 0.436 (36) and this result is listed in the fourth column of Table 16. The values of koH (estimated) for the other carboxylic acids are calculated in the standard manner inAOP and these results are listed inTable 16. The percent error for these compounds, based
-69-on the experimental values of koH listed in the column Experimental/(a), are listed inparentheses in the column Estimated/AOP. Inspection of these results indicate that koH (estimated) for acetic acid was verypoor (an error of -80%). on the otherhand, the average percent error for the other carboxylic acids was -14 which is excellent. Atkinson (1989) reviewed the available koH data for the reaction of OH radicals (or OD radicals) with formic acid (or deuteroformic acids) over the temperature range 297-445 K. Based on the experimental data ofWine et al. (1986) and Singleton et al. (1986) for the reaction of OH radicals with HC(O)OH and DC(O)OH and OD radicals withHC(O)OD and DC(O)OD, Atkinson (1989) concluded that themajor reactionpathway was H- or D-atom abstraction from the -OH(or-OD) groups. This contradicts the assumption ofMeylan (1990b) inAOP; that is, k(-OH) = 0.036 and reaction 33 is the minor reactionpathway. Furthermore, as stated in Section IV.C.3.a., the experimental koH data for these carboxylic acids are available from a single source and the koH data for acetic, propionic, and butyric acids have large uncertainties so that these data must be used with caution. considerablymore experimental koH data are needed for these carboxylic acids and for additional compounds in this class beforereliable S/Rrelationships can be developed. It should be noted that for formic acid, the detailed calculation for H-atom abstraction from formic acid is listed in

-70-

# ..
-· AOP as k[HCOOH **] 

## =0.400 (Measured). The molecular structure for formic acid is [HC(=O)OH] and not HCOOH. IV.C.4. Alcohols, Glycols, Ethers, and Hydroperoxides IV.C.4.a. Evaluation of the Experimental koH Data Table 17 summarizes the pertinent experimental koa data at 298 Kfor the reaction of OH radicals with 16 alcohols, 3 glycols, 26 acyclic ethers, 10 cyclic ethers, and 2 hydroperoxides as reported inAOP, inAtkinson (1989), and in the literature. Inspection of the experimental koa data listed in columns 2 and 3 indicate that five compounds have differences. The differences in four of these compounds are related to the number of significant figures used. Inspection of the original literature references and the data in Atkinson (1989) clearly indicatedthat the preferredvalues are listed in the column Experimental/(a). The experimental values for 1-chloro-2,3- epoxypropane are different; the preferred value listed in the third column represents the average value from the experimental koH data of Zetzsch (1985) and Edney et al. (1986) assuming that koH = 0.55 of Edney. IV.C.4.b. Evaluation of the Estimatedkoa Data Comparison of the estimated values of koa from AOP and HC for the alcohols, glycols, and ethers indicates that they are essentially the same. The trivial differences are due to the method of rounding off the third significant figure in HC.

-71-Table 17. Comparison of the Estimated Values of koH at 298 Kfor Alcohols, Glycols, Ethers, and Hydroperoxides from the Atmospheric Oxidation Computer Program (AOP) and from a Hand Calculation (HC) and the Experimental koH Data Reported in the Literature Versus the Experimental koH Data in AOP 1o12koR(cm3molecule-1s-1) Chemical Class/ChemiJal Experimental Estimated AOP (a) AOP(tError)m HC A. ALCOHOLS Methanol 

### t;:::;**-5~-** 

### I 0.932 0.932* 0.526 0.526 Ethanol 

### &if

## -;:;-s- 3.27 3.27* 3.07 3.08 1-Propanol=11-0!

### 3-3 5.34 5.34* 4.98 4.99 2-PropanofX 5.21 5.21* 6.63 6.63 1-Butanol

## 11-

# 'lt1-3 8.3 8.31b 6.37 6.38 2-Methyl-2-Propanol

### w7-&-::t>**~**0 1.12 1.12* 0.593 0.593 1-Pentanol :::JI-41-o 10.8 10.8° 7.77 7.77 2-Pentanol**(/;o-?;~-.2'7-**

### =t- 11.8 11.8d 10.9 10.9 3-Pentanol**~'9~**-(.);;J

### -I 12.2 12.2d 12.9 12.9 3-Methyl-2-butanol5<78-75 

# 4 12.4 12.4d 11.0 11.0 1-Hexanol /11-J-9--**~** 12.4 12.4d 9.17 9.17 2-Hexanol**/.p;)~-** CJ

### ?rT 12.1 12.1d 12.3 12.3 1-Heptanol 

### 111-

### =fo-(o 13.6 13.6d 10.6 10.6 2-Chloroethanol/07·0

## t-.3 1.4 1.4 2.07 2.07 1-Hydroxy-2-propanone**/~0_-o ~-~,**  3.02 3.02e 2.31 2.32 ._3.H0u._ Cyclopentanol 

### C)tp-

### 41-3 10.7 10.7d 12.8 12.7 B. GLYCOLS 1,2-Ethanediol

### SL/0- v3-(o 7.7 7.7 7.42 7.42 1,2-Propanediol 

## s:r--ss-eo 12.0 12 12.0 11.9

-72-

## .... Table 17. Continued
1o12koH(cm3molecule-1s-1) Chemical



## Cla~Chemical Experimental Estimated AOP (a) AOP(%Error)m HC 

### c. ACYCLIC ETHERS Dimethyl ether 

### II

# o-/O-C.O 2.98 2.98* 1.76 1.76 Diethyl ether 

### &a-02

### 9-

## ::r- 13.3 13.3* 11.5 11.5 Di-n-Propyl ether

### I11-i../3-3 17.2 17.2* 21.1 21.1 Methyl-t-butyl ether/03'-l-oL/-L} 2.83 2.83* 2.82 2.82 Methyl-n-butyl

**ether&<J8~ .~-'-/**  16.4 16.4d 13.6 13.6 Ethyl-n-butyl ether6·o3- 81-9 18.1 18.1f 18.5 18.5 Ethyl-t-butyl ether



### ~Pj/;;**2'S- 3**  6.9 6.88f 7.70 7.20 Methyl-t-amyl ether

### qCJJf-'05-

### S' 7.91 7.91d 6.13 6.13 Di-n-butyl ether

**!'f~**...

### 90- I 22.4 22.4f 25.5 25.5 Di-i-butyl ether

**t~**

### c:l8
-

## ss-

# =r 26.0 26.0g 30.4 30.4 Di-n-pentyl ether{o'jj- &.<J-d 34.7 34.7d 28.2 28.2 1,1-Dimethoxy

**ethane~3~-~~-0** 8.89 8.89e 13.1 13.1 Diethoxymethane

**~0-** 

### o;S-3 16.8 16.8e 16.6 16.6 1,2-Dimethoxypropaneff:f-'8-

### 85-0 14.3 14.3e 22.9 22.9 2,2-Dimethoxypropane

## 11--

**.fto-~** 3.92 3.92e 3.05 3.05 2,2-Diethoxypropane

### /Jto--

## 84-J 11.7 11.1e 12.8 12.8 2-Methoxyethyl

**ether~~~** 17.5 17.5e 28.1 28.1 fI1-'10-(R {01-/

**j</0,~** 19.2e

**1,1,3-Trimethoxypropane/~Y~-9~0** 19.2 28.5 28.5 2-Ethoxyethyl ether

# X 26.8 26.8e 37.9 37.8 Methoxy

**acetoneL5~**1g-I

### c;-

**~)** 6.77 6.77e 4.87 4.87 2-Methoxy ethanol

**/o9-8'~-** 

### t.f 12.5 12.5e 11.2 11.2 2-Ethoxy ethanol 

### 1;0 - 

### S'O-::;- 15.4 15.4h 16.1 16.1 3-Ethoxy-1-propanol /II-35-3 22.0 22.oe 20.9 20.9

**3-Methoxy~1-butanolc2j/1-¥3-3** 23.6 23.6e 20.6 20.6 2-Butoxy ethanol 111-10-,;;. 18.6 18.6h 23.0 23.0

-73-Table 17. Continued 1o12koH(cm3molecule-1s-1) 

### Chemical Class/Chemical Experimental Estimated AOP (a) AOP(%Error)m HC 2-Hydroxyethyl ether /1!-L/r:._--U. (Dihydroxyethyl ether) 30.0 30 20.6 20.6


### o. CYCLIC ETHERS Ethylene oxide

**75--~1-~** 0.076 0.076* 0.224 0.224 1,2-Epoxypropane (propylene oxide) 

### ::t--s--

## .Sto-9 0.052 0.52* 0.543 0.543 1-2-Epoxybutane ( 1 

## t2-

_ 

### 7- I &) -';5tSButylene oxide) '-''tjIf'1

## o 2.1 2.1 1.69 1.69

·

**/<Jt:.-~-e** o.5oi 1-Chloro-2,3-epoxypropane 0.44 0.662 0.662 Trimethylene oxide

### 503-30
...{) 10.3 10.3e 3.73 3.73 Tetrahydrofuran 

### I

### o9-99-

### 9 16.1 16.1* 18.3 18.3 1,3-Dioxane

# s-o

**S-~a -~**  9.15 9.15e 22.1 22.1 1,4-Dioxane 

### /P?r-91-/ 10.9 10.9e 26.4 26.4 1,3,5-Trioxane 

### 1/0-i'iJ-

### 3 6.2 6.2j 15.3 15.3 Oxepane (Hexamethylene oxide) 

## 5"()

-

## CJo

# -s15.4 15.4e 25.7 2.57 E. ALKYL HYDROPEROXIDES Methyl hydroperoxide

### 3o3I

### -13-0 5.54 5.54* 7.24(+31) (1) t-Butyl hydroperoxide

## 9'-/-Zw-€ 3.0 3.ok 1.98(-34) (1)

a Experimental values from Atkinson (1989) and the literature. b Experimental value from Wallington and Kurylo (1987a). The data from campbell et al. (1976) was not used since the validity of the experimental method is questionable [Atkinson (1989)]. c Experimental value from Wallington and Kurylo (1987a). d Experimental value from Wallington et al. (1988b). -74-Table 17. continued

e Experimental value from Dagaut et al. (1988a). f Average value from the experimental data of Wallington et al. (1988b) and Bennet and Kerr (1989). g Experimental value from Bennett and Kerr (1989). h Experimental value from the experimental data of Hartmann et al. (1987) and Dagaut et al. (1988a). i Average value from the experimental data of Zetzsch (1980) and Edney et al. (1986) assuming koH = 0.55x1o-12cm3molecule-1s-1 of Edney. j Extrapolated from the experimental data of Zabernick et al. (1988). k Experimental value from Anastasi et al. (1978). 1 Atkinson did not develop S/Rrelationships for alkyl hydroperoxides. mBased on the experimental values of koij listed in column Experimentalf(a). • Recommended value by Atkinson (1989) w1th the rationale for the recommendation, and the uncertainty for the recommendation.

-75-There are, however, problems with the S/R relationships for the alkyl hydroperoxides inAOP which will be described below. For the alkyl peroxides [RCOOH], Atkinson did not develop S/R relationships while Meylan (1990b}, based on the experimental koa data of methyl andt-butyl hydroperoxide, did develop S/R relationships. For alkyl peroxides, two reaction pathways were postulated byMeylan: H-atom abstraction from the alkyl group and H-atom abstraction from the hydroperoxy groups. Therefore,
RCOOH + ·OH k(1) = k(1a) ·R'cooa + HOH (37} k(2} = k(-OH} RCOOH 

### + ·OH ROO· +HOH (38} where R is an alkyl group and ·R' is an alkyl free radical group. The overall reactionwith OH radicals is then k08

## =k(1} +k(2} = k(1a} + k(-OH) (39} and reaction pathway 37 was considered by Meylan (1990b} to be the dominant reactionpathway. Therefore, Meylan assumed that k(-OH} = 0.036 and F(-0-0- 

## ** } = 50 (40) and k(1a) and k08were calculated in the standard manner. For methyl and**~-butylhydroperoxides,** the estimated values from AOP
were 7.24 and 1.98, respectively. The percent error for these two compounds, based on the experimental values listed in column Experimentalf(a}, were +31 and -34, respectively, and these -76- 

# ...

# ..

results were very good. However, these results, and the S/R relationships of Meylan must be evaluated very carefully in the light of the experimental koH data as described in the following paragraphs. Atkinson (1989) analyzed the experimental rate data of Vaghjiani and Ravishankara (1989) and Niki et al. (1983) for methyl hydroperoxide. The most comprehensive study is that of Vaghjiani andRavishankara (1989) who studiedthe rates of reaction of 16oH, 18oH, and 16ooradicals with cH3ooH and 16oo radicals with CH3ooo. Based on an analysis of all the experimental data, themechanism involves two reaction pathways; H-atom abstraction from the CH3 group and from the OH group. Therefore, k(2) = k(-OH) k(1) = k(1a) (41) (42)
with the ·cH2ooH radical rapidly decomposing to give hydroxyl radicals and formaldehyde (43)
The overall rate, from reactions 41 and 42, is koH

## =k(1) +k(2) 

## =k(1a) +k (-OH) (44)

-77-Relative rate studies gives koH [= k(1a) + k(-OH)] while flash photolysis or laser photolysis experiments, which measure the disappearance of OH radicals, gives only the rate constant k(-OH) assuming that OH radical regenerated contains the same oxygen isotope as the reactant OH radical. Therefore, the reaction of the 16oH radical with ca3o16oa (or 16oo radical with CH3o16oo) gives the rate constant k(-OH). Furthermore, reaction of oo radicals with CH300H yields the overall rate constant koa [= k(1a) + k(-OH)] for the oo radical reaction. Atkinson (1989) carried out a unit-weighted least-squares analysis of the experimental data of Vaghjiani and Ravishankara (1989) for the reaction of 18oH and oo radical with ca3ooH over the temperature range 203-348K. Based on these data, Atkinson recommended the value of k(-OH) 

## =3.73
at 298 K (in the units 1o-12cm3molecule-1s-1); from the experimental data involving 18oH and 00 radicals over the temperature range 223-423 K, Atkinson recommended a value of(45)

k08 = 5.54 (46)
at 298 K (in the units 1o-12cm3molecule-1s-1). Hence, k(1a) = 1.81 (47) and H-atom abstraction from the OH radical in methyl hydroperoxide is the major reaction pathway. -78- 1 •

# ..

For t-butyl hydroperoxide, Atkinson (1989) indicated that because the C-H bonds in the CH3 group are stronger than the 0-H bond, the reaction is expected to proceed principally via H-atom abstraction from the weaker OH bond (reactionpathway 41) and this result is consistentwith the magnitude of koH determined experimentally by Anastasi et al. (1978). Therefore, all the data presented by Atkinson (1989) contradicts the S/Rrelationships of Meylan (1990b) for the alkyl hydroperoxides. Considerablymore experimental rate data is needed for additional alkyl hydroperoxides to develop S/R relationships for this class of compounds. IV.C.5. Alkyl Nitrates and Nitriles IV.c.s.a. Evaluation of the Experimental koa Data Table 18 summarizes the pertinent experimental koH data at 298 K for acyclic and cyclic alkyl nitrates and acyclic alkyl nitriles as reported in AOP, inAtkinson (1989), and in the literature. Inspection of the koH data in columns 2 and 3 indicate that the experimental values for all acyclic and cyclic nitrates are identical. However, for the nitriles, there are differences. For acetonitrile, the correct value of koH is 0.0214* as recommended by Atkinson (1989) and the correct value for propionitrile is 0.194 as given by Harris et al. (1981) and Atkinson (1989).

-79-

# .. Table 18. Comparison of the Estimated Values of koH at 298 Kfor Alkyl

**·~** Nitrates and Alkyl Nitriles from the Atmospheric Oxidation Computer Proqram (AOP) and from a Hand Calculation (HC) and the Experimental koH Data Reported in the Literature Versus the Experimental koH Data inAOP I



# ~ 1o12koH(cm3molecule-1s-1) Chemical Class/Chemical Experimental Estimated AOP (a) AOP HC A. ACYCLIC NITRATES Methyl nitrate

**.St:;g>-~8-**

**~** 0.034 0.034b 0.0259 0.0259 Ethyl

**nitrate~~~ ~8-/**  0.49c 0.49c 0.194 0.194 1-Propyl

### nitratejt.JT·/3-1 0.67 0.67d 0.632 0.632 2-Propyl nitrate 0.41 0.41e 0.416 0.416 1-Butyl nitratejn-ALTYLivi!X:.lJ.ili' 1.78 1.7ae 1.79 1.79 (jJg-¥5-C · 0.92 0.92e 2-Butyl nitrate c'"ffl"/;1./0.3 0.905 0.905 2-Pentyl nitrate\1 1.85 1.a5f 2.06 2.06 3-Pentyl nitrate/ 1.12 1.12f 1.42 1.42 2-Methyl-3-butyl nitrate>:' 1.72 1.72q 1.39 1.39 2,2-Dimethyl-1-propyl nitratey 0.85 0.85q 0.752 0.752 2-Hexyl nitrate)n;-lt.-xyLAJ,

**n,"'~ic** 3.17 3.17f 3.45 3.45 206-33·/1-<y 2.1of 3-Hexyl nitrate

### J c&l-f!3.N'.:J3 2.70 2.58 2.58 2-Methyl-2-pentyl nitrate , 1.72 1.72q 1.68 1.68 3-Methyl-2-pentyl nitrate/ 3.02 3.02q 2.63 2.63 3-Heptyl

**nitrate~** 3.69 3.69q 3.97 3.97 s:..octyl nitrate C,,;J<)-3'}-0 3.88 3.aaf 5.37 5.37 CgH!j/'J()

**~** B. CYCLIC NITRATES cyclohexyl nitrate

### 2/0'B

..**~u-')** 3.30 3.30q 5.38 5.38

c. ALKYL NITRILES Acetonitrile

## -:rs-oS-8 0.021 0.0214* 0.0202 0.0202 Propionitrile 

### Jor-

**;~-o** 0.19 0.194h 0.189 0.189



### -so-••**~J** 

## . ..

Table 18. continued

a Experimental values from Atkinson (1989) and the literature. b Atkinson (1987, 1989) reported a value of 0.034x1o-12 and o.38x1o-12cm3molecule-1s-1 from Gaffney et al. (1986) and Kerr and Stocker (1986), respectively. Atkinson (1987) used the value of 0.034 x 10-12 since itwas more consistent with the entire set of koH data used to develop the S/Rrelationships and the value from Kerr and Stockerwas systematically too high. Atkinson (1989) also tentatively preferred the value of Gaffney et al. (1986) since the value of Kerr and Stockerwas too high. c The experimental data of Kerr and Stocker (1986) was considered too high and was not considered to be valid [Atkinson (1987, 1989)]. d This value of koH represents the average value from the experimental data of Kerr and Stocker (1986) and Atkinson andAschmann (1989a). e Experimental value from Atkinson andAschmann (1989a). f Experimental value from Atkinson et al. (1982a). g Experimental value fromAtkinson et al. (1984b). h Experimental value from Harris et al. (1981). 

## *Recommended value byAtkinson (1989) with the rationale for the recommendation, and the uncertainty for the recommendation.

-81-IV.C.S.b. Evaluation of the Estimated koH Data Inspection of the estimated values for the nitrates and nitriles 

### in columns 4 and 5 indicate that bothAOP and HC have exactly the same koH data. IV.C.6. Nitroalkanes IV.C.6.a. Evaluation of the Experimental k08 Data Table 19.A. summarizes the pertinent experimental koH data .at 298 Kfor nitroalkanes as reported inAtkinson (1989), in AOP, and in the literature. For nitromethane, AOP lists a range of experimental values for k08• Atkinson (1989) evaluated the existing experimental k08 data for nitromethane and indicated that the data of Zabarnick et al. (1988) is preferred. Atkinson carried out a unit-weighted least squares analysis of the Zabarnick data using the equation (48) where Cand 

### Dare constants and T is the absolute temperature in Kand found that

over the temperature range 299-671 K. At 298 K, equation 49 gives

-82- (50) ••

# ...

.... Table 19. Comparison of the EstimatedValues of koa at 298 Kfor Nitroalkanes and Alkyl Nitrites from the Atmospheric oxidation Computer Program (AOP) and from a Hand Calculation (HC) and the Experimental koa Data Reported in the LiteratureVersus the Experiment koa Data inAOP 

### II 1012koH(cm3molecule-1s-1)



# Class/Chemi~ Chemical Experimental Estimated AOP (a) AOP(%Error)j A. NITROALKANES Nitromethane

### :;-s-sOJ-j- (0.016-0.16) 0.0149b 0.0259(+74) Nitroethane

## 1-

**~-** 

## 21-'3 0.15 o.15d 0.194(+29) 1-Nitropropane

### /oe-o3-"'2. 0.24 0.34d 0.632(+86) 1-Nitrobutane

### (:,02

### 7-05-i 1.45 1.45e 1.79(+23) 1-Nitropentane

### &J8-

### o5-7 3.30 3.3od 3.18(-4)
B. ALKYL NITRITES Methyl nitrite

# Wl.f-Cjl-9 (0.12-1.08)? (0.12-1.09)f 0.288 (---) Ethyl nitrite

### /o9-95-S'" 1.75? 1.779 2.32(+31) 1-Propyl nitrite

## 5'-/3

# -61-9 2.38? 2.36h 6.12(+160) 1-Butyl nitriteS'f-1-/(p-/ (2.31-5.2)? 5.o2h 8.29(+65) 2-Butyl nitrite

**9~¥--** 

### 43-!o 5.93? 5.97i 6.17(+3) 2-Methyl-1-propyl nitriteX 5.31? 5.35i 10.8(+101) 2-Methyl-2-propyl

**nitrit~** 1.40? 1.41i 1.94(+38)

a Experimental values from Atkinson (1989) and the literature. b Experimental value from Zabarnick et al. (1988) which represents the preferredvalue by Atkinson (1989). c Could not be calculatedby Leifer since the S/Rrelationships and substituent factors were unknown.

-83- HC
(c) (c) (c) (c) (c)

(c) (c) (c) (c) (c) (c) (c)Table 19A. continued d Experimental value from Nielsen et al. (1988). Atkinson (1989) tentatively accepted this data since "The nitroalkanes are expected to photolyze (Taylor et al. (1990)] and it is not clearwhether photolysis occurredunder the experimental conditions of the relative rate study of Nielsen et al. (1988) orwhether or not photolysis (if it occurred) was taken into account". More experimental k08 data are needed under controlled laboratory conditions to eliminate photolysis. e The average value from the data ofAtkinson (1989) and Nielsen et al. (1988). see footnote (d) above relative to the experimental value from Nielsen et al. (1988). f Range in experimental

### koa data as obtained from Atkinson (1989) and the literature in the units 1o-12cm3molecule-1s-1: 0.12 relative to dimethyl ether and 0.21 relative ton-hexane (Tuazon et al. (1983)]; 1.00 [Baulch et al. (1985); 1.09 (Audley et al. (1982)]; and the data of campbell and Goodman (1975) was omitted since there were fundamental problems associated with the relativemethodused [Atkinson (1989)]. g Experimental value from Audley et al. (1982) and Atkinson (1989). h Average value from the experimental data ofAudley et al. (1982) and Baulch i et al. (1985) is obtained from Atkinson (1989). Experimental value fromAudley et al. (1982). j Percent errorrelative to the experimental values listed in column Experimental/(a).

-84-

### ••



# .

**~·** and this is the value listed in column three of Table 19.A. and is the preferred (or recommended) value by Atkinson. For the remaining nitroalkanes, only for 1-nitropropane is there a discrepancy in the k08 data in columns 2 and 3. The correct experimental value for 1-nitropropane is tentatively 0.34 as obtained from Nielsen et al. (1988) and Atkinson (1989). Some comments must be made about the validity of the experimental koH data for nitroethane, 1-nitropropane, 1-nitrobutane and 1-nitropentane. For nitroethane, 1-nitropropane, and 1-nitropentane, the experimental data were obtained from Nielsen et al. (1988) and Atkinson (1989) while the experimental data for 1-nitrobutanewas obtained from Atkinson and Aschmann (1989) and Nielsen et al. (1988). Atkinson (1989) critically evaluatedthe experimental k08 data of Nielsen and stated that "The nitroalkanes are expected tophotolyze (Taylor et al. (1980)] and it is not clearwhether photolysis occurred under the experimental conditions of the relative rate study of Nielsen et al. (1988) orwhether or not photolysis (if it occurred) was taken into account." As a result, Atkinson (1989) indicated that the data listed in the column Experimentalj(a) for nitroethane, 1-nitropropane, and 1-nitropentane from Nielsen are only tentativelypreferred and, therefore, must be used with extreme caution. IV.C.6.b. Evaluation of the EstimatedkoH Data Leifer did not have available S/Rrelationships for the nitroalkanes from Atkinson; hence, no entries appear in Table -85-19.A., column Estimated/He. Meylan (1990b) did have S/R relationships available for these compounds from Atkinson (unpublished results). For this class of compounds (RN02), Atkinsonmust have postulated that hydroxyl radicals can only react by abstractinq a hydroqen from the C-H qroups in R and the substituent factors were F(-N02) = 0.18 F(-CH2N02) = 0.30 (51) (52) In addition, Meylan (1990b) qave the substituents >CHN02 and >CN02 the same F values as for the substituent -cH2No2 listed in equation 52. Thus, the assumed values for these two substitutes (desiqnated 

### **) are then F(>CHN02 

### ** ) = F(>CN02 

### ** ) = 0.30 (53) Usinq the above substituent factors, AOP estimatedkoH for the five nitroalkanes listed in Table 19.A. and these results are listed inthe column Estimated/AOP. The percent error, relative to the experimental koH data in column 3, are listed in parentheses adjacent to the estimated value from AOP. Inspection of these data clearly indicate that the results for nitromethane and 1-nitropropane are very poor. In addition, the average percent error ranqed from +53 to -4. Therefore, in order to develop better substituent factors for the nitroalkanes, more experimental koH data are needed for these five compounds and additional nitro compounds under carefully controlled laboratory -86-**~·**

conditions to eliminate direct photolysis. Until this work is completed, the substituent factors and estimated values of koH for the nitroalkanes must be used with extreme caution, or, better, delete them from AOP. IV.C.7. Alkyl Nitrites IV.C.7.a. Evaluation of the Experimental koH Data Table 19.B. summarizes the pertinent experimental koH data at 298 Kfor the alkyl nitrites (RONO) as obtained from AOP, from Atkinson (1989), and from the literature. For these compounds, the experimental koH.data from AOP have question marks immediately after the numbers to indicate that the data are questionable. For the experimental data for methyl nitrite, several values are available from the literature. Thus, the experimental koH data in columns 2 and 3 list essentially the
same range of values. For 1-butyl nitrite, AOP lists a range of values while the column Experimentalf(a) lists the average value from the experimental data of Baulch et al. (1985) and Audley et al. (1982). For the other alkyl nitrates there are minor differences listed in columns 2 and 3. The values listed in the third column, as obtained from the literature and Atkinson (1989), appear to be the correctvalues. It should noted that for the compound CH3CH(CH3)cH20NO, AOP lists the name 3-methyl-1-propyl nitrite which is incorrect. The correct name is 2-methyl-1-propyl nitrite.

-87-IV.C.7.b. Evaluation of the Estimated koH Data Leifer did not have available S/R relationships from Atkinson for the alkyl nitrites; hence, no entries appear in the column Estimated/HC. However, Meylan (1990b) did develop S/R relationships for this class of compounds (RONO) by assuming that the only reaction pathway is H-atom abstraction from the C-H groups inR. Based on the available experimental koH data, Meylan assumed that for the nitrites F(-0-N

## =** )

## =2.00 (54) Furthermore, for these compounds, where appropriate, Meylan used the substituent factor F(-CH2-o-) from Table 2. Using the above substituent factors, AOP calculated koHi and these values are listed inTable 19.8. along with the percent error (in brackets adjacent to the estimated values). From an inspection of the percent error data, it is clear that the results are generally verypoor; 1-propyl nitrite and 2-methyl-1- propyl nitrite had percent errors greater than +100 while 1- butylnitritehad a percent error of +65. These results are not surprising sinceAtkinson (1989) Stated "Until the kinetics of OH radicals with alkyl nitrites are fully understood and product studies carried out, the reaction mechanisms remain uncertain. These may proceedvia H-atom abstraction from the C-H bonds

---- and this is expected to be the major, if not the only, reaction pathway ---". Therefore, it is apparent that more reliable koH data and product data are needed for the alkyl nitrites listed in


### -as-Table 19.B. and for other alkyl nitrites in order to develop more reliable S/Rrelationships. IV.D. Addition of Hydroxyl Radicals to Alkenes, Conjugated Dialkenes, Alkynes, and 1,2-Dialkenes· IV.D.1. UnsubstitutedAlkenes IV.D.1.a. Evaluation of the Experimental koa Data Table 20 summarizes the pertinent experimental koa data at 298 Kfor the reaction of OH radicals with unsubstituted alkenes
as reported inAOP, inAtkinson (1989), and in the literature. A careful inspection of the experimental koa data reported in the columns Experimental/AOP and Experimental/(a) indicates that, in general, they are the same; there are, however, some differences. For a few chemicals, AOP lists koa to 4 significant figures while Experimentalf(a) reports koa to 3 significant figures. At best, the experimental k08 data is good to 3 significant figures. For example, for 2,3-dimethyl-2-butene, the experimental k08 data reported inthe literature is only given to 3 significant and Atkinson (1989) recommended a value of 110* while AOP lists a value of 110.0. For the other chemicals with differences, Experimentalf(a) lists an average value from the literature while AOP selects one set. Unless there is good reason to disregard specific sets of data, it is best to list an average value from all the data sets rather than the value from only one set. It should be noted that AOP does not list an experimental value for 43- carene in column 2; however, a value is listed in the document "EstimationAccuracy of AOP versus PCFAP" [Meylan -89-Table 20. Comparison of the Estimated Values of k08 at 298 K for Unsubstituted Alkenes from the Atmospheric Oxidation Computer Program (AOP)**~~** from a Hand Calculation (HC) and the Experimental kQH Data Reported in the Literature versus the Experimental koa Data 1n AOP

Chemical

# Class/Chemica~ 1o12koH(cm3molecule-1s-1) Experimental Estimated AOP (a) AOP HC A. ACYCLIC ALKENES Ethene (Ethylene)

# 9t/-8S-I 8.52 8.52* 8.5200q (r) Propene (Propylene) 

### IIS-o

### 1-1 26.3 26.3* 26.4 26.4 1-Butene 

### /DI.P-

### 9**8"-~** 31.4 31.4* 27.3 27.3 ili-2-Butene 59o-;8-l 56.4 56.4* 56.4 56.4 trans-2-Butene&;J.4-t4-(»**C!./11~** 64.0 64.0* 64.0 64.0 2-Methylpropene;;:)-;;-? c!.f!-1? 51.4 51.4* 51.7 51.7 1-Pentene

### /o'1-r.,--:;-1 31.4 31.4* 28.6 28.6 ill-2-Pentene (p.:J

# r- tJo-

### ..3 65.4 65.7b 57.3 57.3 trans-2-PenteneG:f/CP-**o'l-~** 66.9 66.9c 64.9 64.9 2-Methyl-2-butene

### 5/.3.85'

...'-) 86.9 86.9* 87.3 87.3 2-Methyl-1-butene

### 563·**'~"--** 2. 60.7 60.6d 52.6 52.6 3-Methyl-1-butene

### 5&,3-

### 'Is-/ 31.8 31.8* 28.5 28.5 1-Hexene**59~ -Jf;-~**  37.5 35.2e 30.0 30.0 2-Methyl-1-pentene 

### 1&?;-29-1 62.6 62.6f 53.9 53.9 2-Methyl-2-pentene**{pJ~-**..

### 21-J./ 88.8 89.19 88.2 88.2**trans-4-Methyl-2-pentenetr~~~-o** 60.8 60.5f 66.0 66.0**2,3-Dimethyl-2-butene5~3·7~J** 110.0 110* 111 111**3,3-Dimethyl-1-buteneJD8·37-~** 28.4 28.5h 26.9 26.9 1-Heptene 

### sr:jJ-
..**1~-1-** 40.5 38.3i 31.4 31.4

### 2,3-Dimethyl-2-penten,o5?~-31-S 108.0 103j 111 111**trans-4,4-Dimethyl-2-pentene~** 54.5 54.5f 64.4 64.4**t;?O·o~-** 53.3C 1,4-Pentadiene**~1-93-~** 53.3 53.4 53.4**trans-1,4-Hexadiene~~)-45-o** 90.3 90.6c 91.0 91.0 1,5-Hexadiene

### S9,;t-**'f~**

### -1- 62.1 62.0c 54.8 54.8

-90-Table 20. Continued 

# / l012koH{cm3molecule-ls-1) Chemical



# Clas~ical Experimental Estimated 2-Methyl-1,4-pentadiene-1&3·30-'t 2-Methyl-1 5-hexadienec.

**?HI~** .:2'1Lf1:1:.!..3i--'(? 5tif·U 2,5-Dimethyl-1,5-hexadiene

**(;~1-** 58-1 B. CYCLIC ALKENES cyclopentene 

### lt/-:J-;2

**~-O** Cyclohexene 110-

### 83-8 1,4-Cyclohexadiene

### '2CJ1'}7-09-q Cycloheptene

**tl:l~-q~-** 

## z. 1-Methylcyclohexene

**5~/-l.ft:7-l** Bicyclo [2.2.1]

**-2-heptene'io/5-u-~** C1Hr30 Bicyclo[2.2.1]-2,5-heptadiene /;lJ-"'fa-0 Bicyclo[2.2.2]-2-octene LL

**~31·** "'

**~** a-Pinene $0-

**SIC-~** P-Pinene 1;;;=!-91-3 g-LimoneneS7&9-c:;=f-$"tf 43-carene 13J.jbr/l
-

**18:~_9** -y-Terpinene

**C)~-** 

### ?SS-'f AOP 78.8 96.1 120.0

67.3 67.7 99.4 74.4 94.4 49.3 120.0

40.8 53.7 78.9 171.0 {p) 177.0 {a_) AOP 78.8c 78.7 96.lc 80.0 120c 105

65.5k 58.9 67.7* 61.1 99.51 114 74.4m 62.4 94.4n 92.0 49.3m 62.7 120m 116 40.8m 67.8 53.7* 89.5 78.9* 54.2 160n 145 87.8° 87.6 177° 178

a Experimental values from Atkinson {1989) and the literature. HC 78.7 80.0 105

58.9 61.1 114

62.5 92.0 62.7 116

67.8 89.5 54.1 145

87.6 178

b Average value from the data of Ohta {1984) andWu et al. {1976). c Experimental value from Ohta {1983) and Atkinson {1989). d Average value from the data of Ohta {1984) andWu et al. {1976). The experimental value of

## koH ofMorris and Niki {1971) was considered to be too high and was discountedwhen making recommendations for other alkenes {e.g., for 1-pentene) by Atkinson (1989). e Average value from the experimental data of Wu et al. (1976) and Atkinson and Aschmann (1984). f Experimental value from Ohta (1984) and Atkinson (1989). g Average value of the relative rate data of Ohta {1984) using 2-methyl-2- butene and£1§-2-pentene as reference compounds.
-91-h Experimental value from Wu et al. (1976) and Atkinson (1989). i Average value of the experimental data of Darnall et al. (1976) and Atkinson and Aschmann (1984). j Average value of the relative rate data of Ohta (1984) using 2-methyl-2- butene and 2,3-dimethyl-2-butene as reference compounds. k Average value from the experimental data of Atkinson, Aschmann, and Carter (1983) and the relative rate data of Rogers (1989) with cyclohexene as the reference compound. 1 Average value from the experimental data of Atkinson, Aschmann, and carter (1983) and Ohta (1983). mExperimental value from AtkinsonAschmann, Carter (1983). n Experimental value from Darnall et al. (1976). 0 Experimental value from Atkinson, Aschmann, Pitts (1986). P No experimental value is qiven in the AOP database. An experimental value of 87.8x1o-12cm3molecule-ls-1 is given in the document estimation accuracy of AOP versus PCFAP. q Estimated value is the experimental value. r Cannot be estimated by the S/R relationships of Atkinson. 

## *Recommended value byAtkinson (1989) with the rationale for the recommendation, and the uncertainty for the recommendation.

-92- 

### .....



# ...(1990b)]. The value of 87.8 should be listed in the AOP database. IV.D.1.b. Evaluation of the Estimated koH Data Comparison of the estimatedkoH data in columns 4 and 5 indicates that, in general, they are the same; there are, however, a few differences. For ethene, AOP lists a estimated value of 8.5200 in the summary tablewhich corresponds to the experimental valuewhile HC does not list a value; koH cannot be estimated by the S/Rrelationships of Atkinson. Furthermore, AOP lists the estimated value to five significant figures which is incorrect since the recommended experimental value by Atkinson (1989) is 8.52* which onlyhas three significant figures. For OH addition to olefinic bonds, the detailed calculations show an inconsistency. From themathematical synopsis of the S/R relationships ofAtkinson (equation 15), substituent factors attached to the olefinic group can influence kadd,nar (or kd in Meylan's notation), Table 8; therefore, for consistency in calculatingtherate constant for this reaction pathway, the term C(R) should be used, even though C(R) = 1.00. For example, for 1-pentene, OH addition to the olefinic group should be kadd,nar •

### (CH2•CHR)[C(R)] • 26.3(1.00) (55) kadd,nar • 26.3 For 2-methyl-2-pentene, kadd,nar -93-kadd,nar = 86•9 (56) This comment is also applicable to the compounds listed in Table 22 for the conjugated dienes, and in Table 23 for the allenes and alkynes. For C-H abstraction from the olefinic group (e.g., =C-H), the detailed calculations should include this pathway, even though it is zero [i.e., k(1, UNS CH) = 0). This comment, as well as the above comment, also applies to the other classes of compounds discussed in Section IV.D. IV.D.2. SubstitutedAlkenes IV.D.2.a. Evaluation of the Experimental k08 Data Table 21 summarizes the pertinent experimental koH data for the reaction of OH radicals with substituted alkenes as reported inAtkinson (1989), inAOP, and in the literature. Acomparison of the experimental koH data listed in columns 2 and 3 indicate that, in general, they are the same; there are, however, some differences. For six compounds [i.e., 2-(chloromethyl)-3-chloro1-propene, trans-2-butenal, and the four ketenes, no experimental k08 values are listed inAOP; however, values are reported in the document "EstimationAccuracy of AOP versus PCFAP "[Meylan (1990b)]. The appropriate values should be listed inAOP. For acrylonitrile, AOP lists an experimental value of 4.0 while the correct value should be 4.1, the average value of the
-94-

# .

..'Table 21. Comparison of the Estimated Values of koH at 298 Kfor Substituted Alkenes from the Atmospheric oxidation Computer Program (AOP) and From a Hand Calculation (HC) and the Experimental kQH Data Reported in the LiteratureVersus the Experimental koH Data

**~n** AOP



### Chemical



# Class/Che~ A. Haloalkenes Vinyl fluoride ?5"02-!.)- Vinyl chloride

### =!S-Ol-'-/ Vinyl bromide593-

**~O-** 

### 2... 1,1-Difluoroethene

## :::rs-3<:?"'1 w-1,2-Dichloroethene

**I&/!;D-7~-9** trans-1,**2-Dichloroethene/(,~~~f-(.)** Trichloroethane 

### -=r

### 9-o/-cD (Trichloroethylene) Tetrachloroethane 

### IJ..

### 1'-

### Je>

# -y (Tetrachloroethylene) 3-Chloro-1-propene

### Jo'T- OS"'J (3-Chloropropylene) cis-1,3-Dichloro-1-propene

**/O~t-ol-5** trans-1,3-Dichloro-1-propene lotJ"1-oZ-4:J2-(Chloromethyl)-3-chloro1-propene 18

### fI-57

### -·i C

### 'I /-fW U 1 c:J. B. a,B-UNSATURATED CARBONYLS Acrolein (2-Propenal)/O=t-02-€trans-crotonaldehyde(trans2-Butenal)j;;:;-'13-

### 9 Methacrolein(2-Methyl-2- propenal) 

### -=f-.!5-BS-

### 3 Experimental AOP (a)

5.56 5.56b 6.60 6.6ob 6.81 6.81b 2.1 2.1c 2.38 2.38d 1.80 1.8od 2.36 2.36* 0.167 0.167* 17.0 17*

8.41 8.41d 14.3 14.3d

(e) 33.5d

19.9 19.9*

(e) 36*
33.5 33.5*

-95- Estimated AOP HC

10.5 10.5

5.26 5.26 6.84 6.84 8.22 8.22 2.24 2.24 2.55 2.55 0.695 0.695 0.176 0.176 20.3 20.3

8.85 8.85 10.0 10.0 30.3

22.9 22.9 32.8 32.8
29.6 29.6Table 21. Continued
1o12k (cm3molecule-1s-1) Chemical Class/Chemical Experimental Estimated

IMethyl vinyl ketone

## ':J

**~-9'1-1**

Ketene

**If~**

## 3-51-J./ Methyl ketene>( Ethyl ketene:X Dimethyl keteneY ill-3-Hexene-2,5-dione17""; 1 ,'/-21-S' trans-3-Hexene-2,5-dione

.

**-.S..)o~ (.,c~;;-c;**  C. NITRILOALKENES Acrylonitrile (Cyanoethene) 

### 1or-- 13-t D. ALKOXY ALKENES Methyl vinyl ether

**lor-~s-s** AOP 18.8

(e) (e) (e) (e) 63.1 53.1

4.0

33.5 (a) AOP 18.8* 24.0 173f 51.4

70g 87.0 118f 87.9 107f 110 63.1h 46.7 53.1h 53.0

3.95

33.5b 35.1

a Experimental values from Atkinson (1989) and the literature. b Experimental value from Perry, Atkinson, Pitts (1977a). HC 24.0 51.4 87.0 87.9 110

46.7 53.0

3.95

35.1

c Experimental data not reliable [Atkinson (1989)]. d Experimental value from Tuazon et al. (1988). This data is preferred since these experiments avoided or have taken into account the side reactions of chlorine atoms with the reference compounds [Atkinson (1989)]. e No experimental value is given in the AOP data base. However, experimental values are given in the document EstimationAccuracy of AOP versus PCFAP (Meylan (1990b)]. f Experimental value from Hatakeyama et al. (1985). g Average value from the data of Hatakeyama et al. (1985). h Experimental value from Tuazon et al. (1985). i Average value from the experimental data of Harris et al. (1988) and zetzsch (1983) as reported inAtkinson (1989). * Recommended value by Atkinson (1989) with the rationale for the recommendation, and the uncertainty for the recommendation.

-96- 

# -

# .

**~·** experimental data of Harris et al. (1981) and Zetzsch (1983) as reported inAtkinson (1989). For 3-chloro-1-propene, the recommended value from Atkinson (1989) is 17*, which only has two significant figures, compared to a value of 17.0 listed inAOP.
IV.D.2.b. Evaluation of the Estimatedkoa Data Acomparison of the estimatedvalues of koa listed inAOP andHC for the compounds listed inTable 21 give the same results. The use of four significant figures inthe detailed calculations and

**thr~e** significant figures in the summary table
are applicable in the same manner as described in previous sections. IV.D.3. ConjugatedDienes IV.O.J.a Evaluationof the ExperimentalkoaData Table 22 compares thepertinent experimental koa data at 298 Kfor the reaction of OH radicals with conjugated dienes as reported inAtkinson (1989), inAOP, and in the literature. A comparisonof the experimentalkoadata in columns 2 and 3 indicatethat they are all different. The difference involves the number of significant figures used. For 2-methyl-1,3- butadiene, Atkinson (1989) lists a recommended value of 101* and not 101.0 as listed inAOP. In all the other cases, AOP incorrectly listskoH to four significant figures whereas the literature values listed inAtkinson (1989) and the literature contain only three significant figures.
-97-

# - Table 22. Comparison of the Estimated Values of koH at 298 Kfor Conjugated '• Acyclic and cyclic Dialkenes from the Atmospheric Oxidation computer Program (AOP) and from a Hand Calculation (HC) and the Experimental koa Data Reported in the Literature Versus the Experimental koa Data in AOP 1o12koH(cm3molecule-1s-1) Chemical Class/Chemical Experimental Estimated AOP (a) AOP A.


## ACYCL~IALKENES 1,3-Butadiene

### IOC,-9'1·0 66.6 66.6* 66.6000g

**~-1,3-Pentadiene 1~1~-11-0**  101.0 101b 105 2-Methy1-1,3-butadiene

**7~:-** 1-9--S' 101.0 101* 105 trans-1,4-Hexadiene)( 112.0 112b 106 3-Methyl-1,3-pentadienetp4CJ-:tl/-u 136.0 136b 135 4-Methyl-1,3-pentadieneql(o-_50-7- 131.0 131b 135 2,3-Dimethyl-1,3-butadiene

_ 122.0 122b 135

**513-81~** 210b 2,5-Dimethyl-2,4-hexadiene3

**~** 210.0 231 C-8,/-f!'-/ 70'/- I
- **3-l~ethylene-7-methyl-1,**6- octadiene (Myrcene)/23

### -35"-

### 3 215.0 215c 194 3,7-Dimethyl-1,3,6-octatriene 252.0 252c 223 /3877- 91-3 B. GYCLIC OIAIJ(ENES 1,3-Cyclohexadiene

**59~**

## -s-:;--'-1 164.0 164d 137 1,3-Cycloheptadiene

**</~~-/;!**-D 139.0 139e 139 a-Phellandrene

**9~-8'3-** 

### 2. 313.0 313f 187 a-Terpinene C)CJ-&b-S" 363.0 363f 235

a Experimental values from Atkinson (1989) and the literature. b Experimental value from Ohta (1983). c Experimental value from Atkinson, Aschmann, Pitts (1986). d Experimental value fromAtkinson, Aschmann, Carter (1983). e Experimental value from Atkinson, Aschmann, carter (1984a). f Experimental value from Atkinson et al. (1986). 9 Estimated value is the experimental value. h cannot be estimated by the S/Rrelationship of Atkinson. * Recommended value byAtkinson (1989) with the rationale for the recommendation, and the uncertainty for the recommendation.
-98- HC
(h) 105 105 106 135 135 135 231 194 223

137 139 187 235IV.D.3.b. Evaluation of the Estimatedkoa Data. Acomparison of the estimateddata in columns 4 and 5 of Table 22 indicates that they are identical except for the entree for 1,3-butadiene. For this compound, the value of 66.6000 corresponds to the experimental value [which should be 66.6* as recommended byAtkinson (1989)] and is not an estimatedvalue. There is no entryunder the columnHC since there is no S/R relationship for this compound. IV.D.4. Alkynes and 1,2-Dienes (Allenes) IV.D.4.a. Evaluation of the Experimental koa Data Table 23 summarizes the pertinent experimental koa at 298 K for the reaction of OH radicalswith alkynes and 1,2-dienes (allenes) as reported inAtkinson (1989), inAOP, and in the literature. Acomparison of the experimental koa data reported in columns 2 and 3 are the same except for three differences; for propyne and 1-butyne, the correctvalues with two significant figures, as recommended inAtkinson (1989), shouldbe used in AOP; the value for 1-hexynereportedby Boodegheans et al. (1987) andAtkinson (1989) is 12.6 and not 11.9 as reported by AOP; and finally for propadiene, Atkinson (1989) recommended a value of 9.84* and not 9.82 as reported by AOP. IV.D.4.b. Evaluation of the Estimatedkoa Data Except for ethyne, butadiyne, andpropadiene, the estimated values of koa at 298 K in columns 4 and 5 are identical. For these three compounds, no estimatedvalues appear under the -99-Table 23. Comparison of the Estimated Values of koH at 298 Kfor Alkynes and 1,2-Dialkenes (Allenes) from the Atmospheric Oxidation Computer Program (AOP) and from a Hand Calculation (HC) and the Experimental koH Data Reported in the Literature Versus the Experimental koH Data inAOP
1o12koH(cm3molecule-1s-1) Chemical



# ClassjChem~~ Experimental Estimated AOP (a) AOP A. ALKYNES Ethyne (Acetylene)

## 'JL/-'F{'b-<- 0.815 0.815 0.8150b Propyne

### 7'-/

**~-** 

### 1- 5.90 5.9* 6.54 1-Butyne

**jo=f-OO-~** 8.00 8.0* 7.42 2-Butyne 

### 503- 

### 17-

## 3 27.4 27.4* 29.3 1-Pentyne

### 0Jl-19-0 11.2 11.2d 8.75 1-Hexyne &q3-CJ2--.:t- 11.9 12.6d 10.1 Butadiyne (Diacetylene) 18.9 18.9* 14.08 

### 'l&o-J;J

### -?? B. 1,2 DIENES (ALLENES) Propadiene "/(o3-LJ9

## -o 9.82 9.84* 9.820b 1I2-Butadiene 

### sqo- /t:7j-2_ 26.1 26.1e 31.1 1,2-Pentadiene

## 59J

_

### t!JS-j 35.5 35.5e 32.0 3-Methyl-1,2-butadiene 56.9 56.9e 57.3

**~~-~5-tf** a Experimental values from Atkinson et al. (1989) and the literature. b Estimated value is the experimental value. c cannot be estimated by the S/R relationships ofAtkinson. d Experimental value from Boodaghians et al. (1987). e Experimental value from Ohta (1983). HC
(c) 6.54 7.42 29.3

8.25 10.1

(c)

(c) 31.1 32.0 57.3

* Recommended byAtkinson (1989) with the rationale for the recommendation, and the uncertainty for the recommendation.

-100-

# .. column Estimated/HC since Atkinson never developed S/R relationships for these compounds. It should be noted that the values listedunder the column Estimated/AOP for these three compounds are not estimatedvalues but are experimental values and there are toomany significant figures; they should only have 3 significant figures. IV.E. Reaction of Hydroxyl Radicals with Organic Compounds Containing Sulfur, Nitrogen, and Phosphorous Functional Groups IV.E.l. Reactionwith Thiols, Sulfides, and Disulfides IV.E.l.a. Evaluation of the Experimental koH Data Table 24 summarizes the pertinent experimental koH data for the reaction of OH radicals with alkyl thiols, sulfides, and disulfides as reported inAtkinson {1989), inAOP, and in the literature. Acareful inspection of the experimental koH data in columns 2 and 3 indicate that they are the same except for a few differences. For a few of the compounds, the experimental values in Experimentalf{a) are listedwith only two significant figures whereas the data listed in Experimental/AOP have three significant figures. Acheck on the original literature sources indicate that thekoH values with two significant figures are the correct ones. For example, for 1-butanethiol, the recommended value of koH fromAtkinson {1989) is 51* while AOP lists 51.0. Formethyl ethyl sulfide, the experimental value from Hynes et al. {1986) andAtkinson {1989) is 8.50 and not 8.5 as listed in AOP. For dimethyl disulfide, AOP does not have an entry in column 2 whereas Atkinson {1989) recommends a value of 211*. -101-Table 24. Comparison of the EstimatedValues of koH at 298 Kfor Alkyl Thiols, Sulfides, and Disulfides from the Atmospheric Oxidation computer Program (AOP) and from a Hand Calculation (HC) and the Experimental koH Data Reported in the Literature Versus the Experimental k Data inAOP

**~oH** lo12koH(cm3molecule-ls-1) Chemical

**Class/Chemica~** Experimental Estimated AOP (a) AOP A. THIOLS Methanethiol

### -:;t/-93-

### I 32.9 32.9* 32.3 Ethanethiol 

### 15' -C"B- I 46.8 46.8* 38.7 1-Propanethiol

**/01·03~** 48.3 48.3* 42.0 2-Propanethiol

### =rs-3

### 3-z 42.0 42.0* 47.8 1-Butanethiol/o<f-

### r<J--5" 51.0 51* 43.4 2-Methyl-1-propanethiol 45.0 45* 43.5 513-

**tf~-0** 2-Butanethiol573-S3-I 40.0 40* 53.7 2-Methyl-2-propanethiol 33.1 33.1* 31.6

**;.s-:~-1** 54.3b 2-Methyl-1-buta et 101 54.0 44.9

**18¥&-Jtr-~** B.l. ACYCLIC SULFIDESe Dimethyl sulfide15-J2-3 4.56 4.56* 4.59 Methyl ethyl sulfide 8.5 8.soc 11.0 Diethyl

**sulfide~oo-z4-~** 15.0 15* 17.5 Di-n-PropylSulfidet//-'!1--f 20.0 2o.od 24.0

**(Jol-{/~6** B.2. CYCLIC SULFIDE e Tetrahydrothiophene 19.7 19.7* 19.8 /to-ol-o c. DISULFIDES Dimethyl disulfide (f) 211* 203 

### =;s-JB-3

a Experimental values from Atkinson (1989) and the literature. b Experimental value from Barnes et al. (1986). HC 32.3 38.7 42.0 47.8 43.4 43.5 53.7 31.6 44.9

2.59 9.02 15.5 22.0 17.8 203

c Experimental value fromHynes et al. (1986). d Experimental value from Barnes et al. (1986). The experimental value of Nielsen et al. (1987) appear to be erroneous [Atkinson (1989)]. e For these compounds, koH was measured in the absence of oxygen.

-102- 

## ....Table 24. continued f No experimental value is given in the AOP database. An experimental value of 211x1o-12cm3molecule-1s-1 is given in the document "Estimation Accuracy of AOP versus PCFAP" [Meylan (1990b)]. •·Recommended value by Atkinson (1989) with the rationale for the recommendation, and the uncertainty for the recommendation.

-103-Finally, for 2-methyl-1-butanethiol, the correct experimental value of koa in column 3 is 54.3 obtained from Barnes et al. (1986) and-Atkinson (1989), and not 54.0 as reported by AOP. IV.E.1.b. Evaluation of the Estimated koa Data Acomparison of the estimatedkoa data from AOP and HC indicates that they are the same except for the alkyl sulfides (acyclic and cyclic). For all these sulfides, koa is larger from AOP than from HC. The reason for the differences will be described in the following paragraphs. In estimatingk0a, there are two reaction pathways for the reaction of OH radicals with alkyl (acyclic and cyclic) sulfides: (i) H-atom abstraction from the C-H groups in the alkyl groups; and (2) OH radical interaction with the sulfide group to form the adduct (>S····OHJ which then decomposes rapidly in the presence of oxygen to form the products. The total rate of reaction is then given by the**eq~ation** koa

## =k(l) +k(4) 

## =k(1) + k(-S-) (57) In the absence of oxygen, k(-S-) is zero [Atkinson (1987) and Leifer (1992a)) so that equation 57 becomes koH

## =k(1) and only C-H abstraction from the alkyl groups takes place. In estimatingk0H, AOP uses equation 57 while HC uses equation 58 and this is the reason why koa (AOP) >koH(HC). Since the experimental values listed in the column -104- (58)

# . •• Experimentalf(a) were obtained in rate measurements without oxygen, koa must be evaluated using equation 58. Therefore, AOP must qualify the experimental k08 value for the alkyl sulfides to indicate that the data were obtained in the absence of oxygen; and thus, only H-atom abstraction occurs. Then, in the detailed calculation section, AOP must indicate that k(-S-) 

## =o in the absence of oxygen. IV.E.2. Reaction with Sulfoxide& and Sulfates IV.E.2.a. Evaluation of the Experimental koa Data Table 25

**summa~izes** the pertinent experimental koH data at 298 Kfor alkyl sulfoxides and sulfates as reported in Atkinson (1989), inAOP, and in the literature. Acomparison of the experimental data in columns 2 and 3 indicate that only for dimethyl sulfoxide is there a difference. The experimental value from Barnes et al. (1986) andAtkinson (1989) is 62 and not 62.0· as listed inAOP. IV.E.2.b. Evaluation of the Estimated koH Data Atkinson did not develop S/Rrelationships for alkyl sulfoxide& and sulfates; hence, there are no estimated values listedunder the column Estimated/HC. Meylan (1990b) did develop S/Rrelationships for these classes of compounds as described in the following paragraphs. In developing S/Rrelationships for the alkyl sulfoxides, Meylan (1990b) assumed that only c-H abstraction occurred from the alkyl group. Therefore,
-lOS-Table 25. Comparison of Estimated Values of koij at 298 Kfor Alkyl Sulfoxides and sulfates from the Atmospheric

**ox~dation** computer Program (AOP) and from a Hand Calculation (HC) and the Experimental koa Data Reported in the Literature Versus the Experimental k08 Data inAOP

Chemical



# Class/Chemical~ 1o12koH(cm3molecule-1s-1) Experimental Estimated AOP (a) AOP(\Error)f A. SULFOXIOES Dimethyl

**sulfoxideb~-hg-s-** 62.0 62b 28.5(-54) B. SULFATES Dimethyl sulfate



### 11-1-~

### -1 <0.5 <0.5c 1.76{>+250) Diethyl sulfate

### &tf--

### lt;)f-S' 1.8 1.8d 11.5(+540)

a Experimental values from Atkinson (1989) and the literature. b Experimental value from Barnes et al. (1986). c Experimental value from Japar et al. (1990). d Experimental value from Japar et al. (1990a). e Atkinson did not develop S/Rrelationships for alkyl sulfoxides and sulfates. f Calculatedusing the experimental value listed in Experimentalf(a).

-106- HC
(e)
(e) (e)koa = k(1) (59) F[S{+4) 

### ** ] 

## =99.000 (Table 2) (60) Using equations 59, 60, and 11, AOP estimated that koa was 28.5 and the percent error, relative to the experimental value listed in the column Experimental/(a), was -54 (listed inparentheses adjacent to the estimatedvalue in column 4). However, intuitively, it is expected that the sulfoxide group would undergo further oxidation to the sulfone in the presence of oxygen R-S(•O) + ·OH

--- 0 II 

# r-s·· ·

·OH

## 1 Rapid 02 Products {61)

and this reactionpathway should be considered in the S/R relationships. Therefore, considerablymore experimental koa data are needed on OH radical reactionwith a member of alkyl sulfoxides (both acyclic and cyclic) and aromatic sulfoxides to determine the reactionmechanism and to develop S/Rrelationships for this class of compounds. As a result, it is recommended that Meylan drop the S/Rrelationships for this class of compounds from AOP. For the alkyl sulfates, Meylan {1990b) assumed that koH = k(1) (62)
and the substituent factors F(-0-) and F(-CH2

### -o-) were valid. Using equations 62 and 11 along with the appropriate substituent -107-Table 27. continued



### Chemical

# Class/Ch~**10 12** **kn~(cm3molecule-1s-1)** Experimental Estimated AOP (a) AOP HC B. DIALKYL CHLOROPHOSPHOROTHIOATES o,o-oimethyl chlorophosphorothioate (CH3o)2P(S)Cl 

### ;JSJLj-03-0 59.0 59.oc 60.8 60.8



## c. ALKYL PHOSPHOROAMIDATES AND ALKYL PHOSPHOROTHIOAMIDATES O,O-Dimethyl phosphoroamidothioate 244.0 244e 80.8 80.8 (CH30)2P(S)NH2 I 

### 1/J.:..J;-

### 1/7-(' ( "lit,<jAJ(J2P5 O,O,N-Trimethyl 

## y phosphoroamidothioate 232.0 232e 122 122 (CH30)2P(S)NHCH3 o,o,N,N-Tetramethyl '' phosphoroamidothioate 

### !\ 46.8 46.8e 124 124 (CH30)2P(S)N(CH3)2 o,o,N,N-Tetramethyl phosphoroamidate (CH30)2P(O)N(CH3)2 31.9 31.9e 68.6 68.6

a Experimental data from the literature. b Experimental data from Atkinson (1989) and Tuazon et al. (1986). c Experimental data from Atkinson (1989) and Atkinson et al. (1988). d Experimental data from Atkinson (1989) and Goodman et al. (1988). e Experimental data from Atkinson (1989) and Goodman et al. (1988a)

.
-112-trimethyl phosphate, the summary table should be Reaction with N,P,S, and OH and the detailed calculation should be Reaction with Nitrogen. Phosphorous. Sulfur. and -OH k[P(=O)] = 0.000 (63) and for (CH3o)2P(=S)NH2, the summary table should be Reaction with N,P,S, and OH and the detailed calculation should be Reactionwith Nitrogen. Phosphorous. Sulfur, and -OH k[P(=S)] = 55.0 (64) (65) IV.F. Reaction of Hydroxyl Radicals with Aromatic Compounds, Heterocyclic Aromatic Compounds, and Fused Ring Polyaromatic Compounds IV.F.1. Aromatic Compounds IV.F.1.a. Evaluation of the Experimental koH Data Table 28 summarizes the pertinent koH data for the reaction of hydroxyl radicals with a number of chemicals in a variety of classes of aromatic compounds as reported in Atkinson (1989), in AOP, and in the literature. Acareful inspection of the experimental koH data in columns 2 and 3 indicate that they are the same except for some differences. In a few cases, AOP lists the experimental values with more significant figures than the values reported on the literature. For example, for styrene, AOP lists a value of 58.0 while the recommended value by Atkinson (1989) is 58*. For aniline, AOP lists a value of 111.0 while -113-• 

## ,} Table 28. Comparison of EstimatedValues of koH at 298 Kfor Aromatic Compounds from the Atmospheric Oxidation Program (AOP) and from Hand Calculation (HC) and the Experimental kQH Data Reported in Literature Versus the Experimental koH Data**~n** AOP



### Chemical

## Class/Chemica~ A. UNSUBSTITUTED AROMATIC COMPOUNDS Benzene 

### =!1-'-13-1 Biphenyl

### q;;**~s()-L/** B. ALKYLBENZENES Methylbenzene (Toluene) 

### ;o**~-** s-a-3 Ethylbenzene/oO

### -¥1-J.f n-Propylbenzenejo?rft:JS-

### J i-Propylbenzene**q&'~z-g** t-ButylbenzeneC)'II-ol.-(p Q-Xylene**t:}~~4f1-lo** m-Xylene**;o~-3~- ~**  R-Xylene**/()~ -~~-**  3 Q-Ethyltoluenefoll-/'-1-

### 3 m-Ethyltoluene**(p~o-** !+'f R-Ethyltoluene d;;)J-Cjfo-g 1,2,3-Trimethylbenzene**~(Q-** =t-3-8 1,2,4-Trimethylbenzene 9S-**~3-<D** 1,3,5-Trimethylbenzene 

### ;o??-

### h7-'8 a the
1012koH(cm3molecule-1s-1) Experimental Estimated AOP (a) AOP HC

1.23 1.23* 2.04 2.04 7.2 7.2* 7.12 7.12

5.96 5.96* 5.51 5.51 7.1 7.1* 6.13 6.13 6.0 6.0* 7.46 7.46 6.5 6.5* 7.08 7.08 4.60 4.6ob 5.08 5.08 13.7 13.7* 6.88 6.88 23.6 23.6* 14.4 14.4 14.3 14.3* 6.88 6.88 12.3 12.3* 7.72 7.72 19.2 19.2* 14.6 14.6 12.1 12.1* 7.72 7.72 32.7 32.7* 17.8 17.8 32.5 32.5* 17.8 17.8 57.5 57.5* 37.5 37.5

-114- 

### ..c. • Table 28. continued

Chemical Class/Chemical Experimental 

### tf,--+---- AOP (a) C. ALKENYLBENZENES**Ja:J-'-/~**-6- Phenylethene (Styrene) 2-Phenyl-1-propene

### a ..o

### (a-Methylstyrenef/t-~3 ' 1-Phenyl-1-propene**~**

### 3

# r-so-3**(~-Methylstyrene)** 1-Phenyl-2-methyl- cH,Nifj_ 1-propene {16**-11-~ (~-Dimethylstyrene~**  D. HALOBENZENES Fluorobenzene**'-/to~--~-~** Chlorobenzene/o8-c;Jo--=1- Bromobenzene/08-?S(Q-/ Iodobenzene

### SC}J-s-o-4- .Q-Dichlorobenzene

### 95"SZJ-J m-Dichlorobenzene

### 9-fl-

### 13-J R-Dichlorobenzene**/o~-'16-7** 1,2,4-Trichlorobenzene1 /.:J0-87.-- Hexafluorobenzene**392.-~#**

### 3n-Propylpentafluorobenzene '/ C})HtFS E. HALOALKYLBENZENES

Benzotrifluoride

## 98"-of-t**4-Chloro~enzotrifluoride ~~-G1** **C~HJ7CRF3** Benzyl c ,lorJ.de '38'-88-'f 58.0

33.0

0.69 0.77 0.77 1.1 0.42 0.72 0.32 0.532 0.172 3.06

0.46 0.24 2.9

-115- 58*

59c

0.69* 0.77* 0.77* 1.1* 0.42e 0.72e 0.32e 0.532f 0.172*

0.46h 0.24h 2.9* Estimated AOP

28.2 53.5 65.8

89.1

2.56 1.43 1.28 1.34 0.414 1.01 0.414 0.291 0.151 2.89

0.406 0.285 2.42 HC

28.2 53.5 65.7

89.1

2.56 1.42 1.28 1.34 0.414 1.01 0.414 0.291 0.151 2.90

0.406 0.285 2.43Table 28. continued 1012koH(cm3molecule-1s-1) Chemical**Class/Chemic~** Experimental Estimated AOP (a) AOP HC 

### F. MONOCHLOROBIPHENYLS 2-Chlorobiphenyl2c5l- W--=1 2.8 2.82i 2.95 2.95 3-ChlorobiphenylZC::OI-l.ol-8' 5.3 5.28i 4.42 4.42 4-Chlorobiphenylldi**1-~2- ~**  3.9 3.86i 2.95 2.95
G. HYDROXYBENZENES Phenol**I08-~5'**-'2.... 26.3 26.3* 35.7 35.6 .Q-Cresol**~5-"f~-1-** 42.0 42* 43.9 43.9**m-cresolJog-39-~** 64.0 64* 93.9 93.9 R-Cresol**10~-~-~-** 47.0 47* 43.9 43.9 2,3-Dimethylphenol52.lo-?5·0 80.2 80.2j 115 115 2,**4-DimethylphenolloS"-~~-'?** 71.5 71.5j 54.1 54.1 2,**5-DimethylphenolC]S-~1-·~** 80.0 8o.oj 115 115**2,6-Dimethylphenol51~-2w'** 65.9 65.9j 54.1 54.1 3,**4-Dimethylphenol<::}":)-(;,5"-~** 81.4 81.4j 115 115**3,5-Dimethylphenoll~-~~9** 113.0 113j 200.3 200 2,3-Dichlorophenol).(l.o-ZJ.I-'} 1.66 1.66k 7.27 7.27 2,4-DichlorophenoliZo-83-..,_ 1.06 1.06k 3.02 3.02

H. NITROBENZENES Nitrobenzene**"8-~S-** 

### 3 0.14 0.1491 0.251 0.251 .Q-Nitrophenol**8~-** -=15"-:J 0.90 0.90 4.42 4.42 .Q-Nitrotoluene**~2-12.-L.** 0.70 0.70 0.805 0.805 m-Nitrotoluene

### 99-of!-1 0.95 0.95 0.605 0.605

-116-••Table 28. continued lol2koH(cm3molecule-ls-l) Chemical



### Class/Chemic~ Experimental Estimated AOP (a) AOP HC I. AMINOBENZENES Aniline

**~;2--53-** :3 111.0 111* 136 136 N,N-Dimethylaniline

**IZI-U.er~** 148.0 148m 263 200

**Q-ChloroanilinejO~-~~-~** 83.0 83.on 53.6 53.6 2,4-Toluenediamine

**qs--~o-1-** 192.0 192° 240 200
J. ADDITIONAL SUBSTITUTED BENZENES Methoxybenzene 

### laD-(:,{;;,-

### .3 17.3 17.3* 23.8 23.8 Benzonitrile

### joo-L/-=}-0 0.33 0.33 0.356 0.356 Benzaldehyde}

### a:?

## -s-()-

# r 12.9 12.9* 17.1 17.1 Acetophenone

**q~**-&<o-2.. 2.74 2.74P 1.61 1.61 Thiophenol

### /o8-98-S"" (Mercaptobenzene) 11.2 11.2q 13.3r 13.3r Benzyl alcohol

**joO-SJ-~** 22.9 22.9 7.99 7.99 Tetralin (1,2,3,4-

**/1'1-~-** 2.. Tetrahydronaphthalene) 34.3 34.38 11.1 11.2 Indan (2,3-Dihydro- 9.2t lH-indene)

**49~-1**

### 1-7- 9.2 9.71 9.09 Fluorene (9H-Fluorene) 13.0 13.ou 9.42 9.37 gt;-73-1' 1,4-Benzodiox1n 25.2 25.2 33.0 33.0

**2,3-Dihydrobenzofura~** 36.6 36.6 38.0 36.3

**'-1~4:>-**

# rl.

**~-** 1,4-Naphthoqu no e 3.1 3.1 2.75 2.75 

### }3o-

# /S-f

-117-Table 28. continued

a Experimental data from Atkinson (1989) and the literature. b Experimental data from Ohta and Ohyama (1985). c Experimental data from Bignozzi et al. (1981). d Experimental data from Chiorboli et al. (1983). e Experimental data from Wahner and Zetzsch (1983). f Experimental data from Rinke and Zetzsch (1984). g Experimental data from Ravishankara et al. (1978a). h Experimental data from Atkinson et al. (1985a). i Experimental data from Atkinson andAschmann (1985). j Experimental data from Atkinson andAschmann (1989). k Experimental data from Nolting et al. (1987). 1 Average of the experimental data of Witle et al. (1986) and Zetzsch (1982) as reported in Atkinson (1989). mExperimental data from Atkinson et al. (1987)•. n Experimental data from Wahner and Zetzsch (1983). 0 Experimental data from Becker et al. (1988). P Experimental data from Nolting et al. (1987) and Atkinson (1989). q Experimental data from Barnes et al. (1986). r For the thiol group on an aromatic ring, itwas assumed that k(4)•k(-SH)=O [Meylan (1990)]. s Experimental data from Atkinson and Aschmann (1988a). t Experimental data from Baulch et al. (1986) as reported by Atkinson (1989). u Experimental data from Klopffer et al. (1986) and Becker et al. (1984) as reported inAtkinson (1989). 

## * Recommended value byAtkinson (1989) with the rationale for the recommendation and the uncertainty for the recommendation.

-118- •••• Atkinson (1989) recommends a value of 111*. In a few cases, AOP lists fewer significant figures than the values reported in the literature. For example, for 4-chlorobiphenyl, AOP reports a value of 3.9 while Atkinson and Aschmann (1985) and Atkinson report a value of 3.86. It should be noted that for 1,4-benzodioxin, AOP lists the
erroneous name 1,4-dibenzodioxin; and finally, for aniline, AOP first lists the experimental value for iodobenzene and when a key ispressed, the correct experimental value for aniline is displayed. IV.F.1.b. Evaluation of the Estimated Data Acomparison of the estimated values of koH by AOP and HC in Table 28 indicates that they are the same except for some differences. First, consider the compounds 3,5-dimethylphenol, N,N-dimethylaniline, and 2,4-toluenediamine. In all three cases, AOP lists a maximum value of the rate constant for OH addition
to an aromatic ring [i.e., k(7) = kadd,ar, equation 20] as 200 x 1o-12cm3molecule-1s-1whereas HC lists a maximum value of koH [equation 9] as 200 x 1o-12cm3molecule-1s-1. Since the maximum allowed collisionrate is 200 x 1o-12cm3molecules-1 [Atkinson (1987)], this boundary conditionmust be invoked on the estimation of koH andnot onthe estimation of k(7) = kadd,ar· It should be noted that this is only applicable to aromatic compounds and not to other compounds (e.g., dimethyl disulfide, a-terpinene, a-phellandrene, etc.) For the compounds tetralin, indan, and fluorene, AOP makes

an error in calculatingk(7) 

## =kadd,ar· For these three -119-compounds, AOP uses the incorrect value of

# ai (-CH2-) 

## =0.06** instead of the correct value of -0.064** [see Section IV.A., page 40, Table 9, No. 41 and Leifer (1992a), Table 22, page 109]. Furthermore, for the compounds tetralin, indan, fluorene, and 2,3-dihydrobenzofuran, which contain five membered rings, AOP calculates k(1c) erroneously. That is, for these compounds, AOP makes an error by omittingthe ring strain factor F(5) for the five membered ring. As a result, the values of koH for these compounds are erroneous. Finally, for

**t~e** compounds P-methylstyrene, chlorobenzene, n-propylpentafluorobenzene, benzylchloride, and phenol, the small differences between the estimatedk08 fromAOP and HC are a result of themethod of rounding off the last digit. IV.F.2. HeterocyclicAromatic Compounds IV.F.2.a. Evaluation of the Experimental koH Data Table 29 summarizes the pertinentk08 data for the reaction of hydroxyl radicals withheterocyclic aromatic compounds as reported inAtkinson (1989), inAOP, and in the literature. Inspection of the experimental koH data in columns 2 and 3 indicate that there are a few differences. For pyrrole, the recommended value byAtkinson (1989) is 110* whereas AOP reports a value of 110.0 which contains one more significant figure than is warranted from the experimental data; and for 1,3,5-triazine, the value from Atkinson et al. (1987) and Atkinson (1989) is 0.145 whereas AOP rounds off the data to 0.15. For imidazole and
-120-J •Table 29. Comparison of the EstimatedValues of koH at 298 Kfor Heterocyclic Aromatic Compounds from the Atmospheric oxidation Program {AOP) and from a Hand Calculation {HC) and the Experimental koa Data Reported in the Literature Versus the Experimental koH Data inAOP 1o12koH(cm3molecule-1s-1) Chemical / Experimental Estimated AOP (a) AOP Furan

### Ilo-oo-9 40.5 40.5* 4o.5b 3-Methylfuran

### 930-2-=f-

**~** 93.5 93.5d 106.7{+14)h Thiophene

### /lo-o2

### -1 9.53 9.53* 9.53b Pyrrole 

### /oCJ-'>1-1- 110.0 110* b 110.0 Imidazole



### 28~- **32-~** 36.0 35.9e 36.ob oxazole

**z..a~-i/2.-CP** 9.1 9.1e 9.1ob Thiazole

### 288-4

### 7-J 1.40 1.41e 1.40b Pyridine 

## J/o-"8v1 0.37 0.37f o.37ob 1,3,5-Triazine 0.15 0.145g 0.150b 

## '290-

**8:t-~** a Experimental data from Atkinson {1989) and the literature. b Experimental data for this compound. c Cannot be calculatedby HC sinceAtkinson did not develop S/Rrelationships for these types of compounds. d Experimental data from Atkinson et al. (1989b). e Experimental data from Witte and Zetzsch (1986) and Atkinson (1989). f Average value from the data of Atkinson et al. (1987) and HC (c) (c) (c) (c) (c) (c) (c) (c) (c)

Witle and Zetzsch {1986) as reported by Atkinson {1989). g Experimental value from Atkinson et al. {1987) as reported by Atkinson (1989). h Percent Error from the value of koH in column Experimentalf(a).

-121-thiazole, the correct values of koH obtained from Witte and Zetzsch (1986) and Atkinson (1989) are 35.9 and 1.41, respectively, and not 36.0 and 1.40 as listed in AOP. IV.F.2.b. Evaluation of the Estimated koH Data Atkinson did not develop S/Rrelationships for heterocyclic aromatic compounds whereasMeylan (1990b) did develop S/R relationships for this class of compounds. Meylan used an approach similar to the one used byAtkinson for aromatic compounds (equations 20, 21, and 22). Thus, Meylan postulated that equations 23 and 24 are applicable to heterocyclic aromatic compounds where: (1) Ai is a constantwhich is equal to the experimental value of koH for theparent heterocyclic aromatic rinq; and (2) the second term is identical to the one used by Atkinson for substituents on the aromatic rinq [i.e., -1.35 Min <l:aj) in equation 21]. The values of Ai are qiven in Table J 10 for a number of parent heterocyclic aromatic rinqs. The only available experimental koH data for this class of compounds is for 3-methylfuran, a substituted furan. Atkinson (1989b) reported a value of 93.5 for this compound. The estimated value of koH obtained from equations 23 and 24 is 106.7 which qives a percent error of +14 which is excellent. However, more experimental koH data are needed for a number of substitutedheterocyclic aromatic compounds listed inTable 29 to confirmthe validity of equations 23 and 24.

-122-

# . ' IV.F.3. Fused Rinq Polyaromatic Compounds IV.F.3.a. Evaluation of the Experimental koa Data Table 30 summarizes the pertinent experimental koa data for the reaction of hydroxyl radicals with fused rinq polyaromatic compounds [i.e., fused rinq polyaromatichydrocarbons (PAH)]. Inspection of the data in columns 2 and 3 indicate that they are the same except for a few differences. For anthracene, the correct value is 112 as reported by Biermann et al. (1985) and Atkinson (1989) and not 110.0 as reported by AOP. For phenanthrene, the recommended value by Atkinson (1989) is 31* and not 31.0 as reported by AOP. Unfortunately, there are no available experimental koa data for fused rinq polyheteroaromatic compounds published in the literature. Hence, there are no entries in Table 30 for this class of compounds. IV.F.3.b. Evaluation of the Estimatedkoa Data Acomparison of the estimatedvalues of koa in columns 4 and 5 of Table 30 indicate that they are the same except for a few differences. The differences are related directly to the dissimilarity betweenthe S/Rrelationships of Atkinson [equations 26, 27 and 28] andMeylan [equation 29]. First of all, AOP uses the experimental value of koa for the parent PAH (which is Bi in equation 29) while Atkinson uses the ionization potential of the parent PAH. For naphthalene, both methods qive essentiallythe same results; however, for anthracene and

-123-Table 30. Comparison of the Estimated Values of koH at 298 Kfor Fused Ring Polyaromatic Compounds (PAH) from the Atmospheric Oxidation Program (AOP) and from a Hand Calculation (HC) and the Experimental koH Data Reported in the Literature Versus the Experimental koH Data inAOP 1o12koH(cm3molecule-1s-1) Chemical Experimental Estimated AOP (a) AOP Naphthalene

### 91-.;l

### o-

## 3 21.6 21.6* 21.6b 1-Methylnaphthalene9o-rz-o 53.0 53.0C 56.9

**2-Methylnaphthalene91-S1-~** 52.3 52.3d 56.9 2,3-Dimethylnaphthalene 76.8 76.8d 70.0 .;::'-

**Ll~**

### -e 5.4e 1-Nitronapht lene

**~** 5.4 2.66 

### at.a-St"' 5.6e 2-Nitronaphthalene 89 _ 5.6 2.66 

### 58h -,!) 5.8f 1,4-Dichloronapht alene 5.8 4.38 182.5-aJ-(o 110.0 112g 11o.ob

**Anthracen~~** 

## r 0
.. /2.- 31.ob Phenanthrene 31.0 31* 85"-o/-

### '8'
a Experimental data from Atkinson (1989) and the literature. b Experimental data for this compound. HC 21.4 56.3 56.3 69.5

2.63 2.63 4.37 91.2 22.9

c Experimental data from Atkinson and Aschmann (1987). d Experimental data from Atkinson and Aschmann (1986). e Experimental data from Atkinson et al. (1989d). f Experimental data from Kl6pffer et al. (1986) and Becker et al. (1984) as reported inAtkinson (1989). g Experimental data from Biermann et al. (1985). * Recommended values byAtkinson (1989) with the rationale for the recommendation, and the uncertainty for the recommendation.

-124- •

## .. f t

## .. l • phenanthrene, AOP gives the most reliable results. For the substituted naphthalenes, AOP and Atkinson (HC) give essentially the same results. However, more experimental koH data are needed for considerably more substitutedpolyaromatic hydrocarbons to
see how reliable bothmethods are. Since there are no experimental koH data for fused ring heterocyclicpolyaromatic compounds (i.e., quinoline, isoquinoline, quinoxaline, quinazoline, and acridine), Meylan's S/Rmethod cannot be evaluated. Thus, experimental koH data is needed on a number

**~f** compounds inthis class of compounds to confirm and refine the AOP method (i.e., equation 30). IV.G. Evaluation of the EstimatedHalf-Life for the Reaction of Hydroxyl Radicals with Organic Chemicals in the Troposphere Meylan (1990b), inAOP, estimatedthehalf-life [tc1/2)El for the reaction of hydroxyl radicals with organic chemicals in the troposphere by assuming that the average OH radical concentrationwas 5 x 105 radicals cm-3 and a 24-hour daylight day. The assumption of a 24-hour daylight day is incorrect. on the average, a 12-hourdaylight day ismore reasonable. [Leifer (1992a)]. In addition, based on the literature data (Leifer (1992a)], the average OH radical concentration is closer to 1.5 x 106 radicals cm-3. Therefore, itwas recommended that the AOP computer programbe changed to the atmospheric conditions described above. This has been done by Meylan in a later version of AOP.
-125-For olefins and acetylenes, which can react with hydroxyl radicals and ozone, it is desirable to have knowledge of the overall oxidative half-life inthe troposphere. Therefore,

I I kox = koH + ko3 (66)

I I where koH and k03 are the first-order rate constants for reaction of an organic chemical in the troposphere with respect to hydroxyl radicals and ozone, respectively, as calculated under the atmospheric conditions (OH) 

## =1.5 x 106 radicals cm-3 and a 12-hour daylight day and (03) = 7 x loll molecules cm-3; and the overall oxidativehalf-life is given by the equation [tc1

### t2

### >]ox = o.693/kox (67) Thus, AOP should add SUMMARY: OXIDATION kox = (68) t(l/2)ox = (69)

-126- 

# . v

## v. References Anderson, L.G.; Stephens, R.D. (1988). Int. J. Chem. Kinet. 1Q, 103-110. Kinetics of the Reaction of Hydroxyl Radicals with 2-(Dimethylamino)ethanol from 234-364 K. Anastasi, C.; Smith, I.W.M.; Parkes, D.A. (1987). J. Chem. Soc. Faraday Trans. 1, 

### li, 1693. Arey, 

### J.; Atkinson, R.; Zielinska, B.; McElroy, P.A. (1989). Environ. Sci. Techno!.**~,** 321-327. Diurnal Concentrations of Volatile PolycyclicAromatic Hydrocarbons and Nitroarenes During a Photochemical Air Pollution Episode in Glendora, California. Arrhenius, 

### s. (1887). 

## z. Physik Chem.**~,** 110. Atkinson, R.**(1986)~** Chem. Rev. 

### 12, 69-201. Kinetics andMechanisms of the Gas Phase Reactions of the Hydroxyl Radical with Organic Compounds under Atmospheric Conditions. Atkinson, R. (1986a). Int. J. Chem. Kinet.**~,** 555-568. Estimation of OH Radical Rate Constants for H-Atom Abstraction from c-H and o-H Bonds over the Temperature Range 250-1,000 K. Atkinson, R. (1987). Int. J. Chem. Kinet. 

### li, 799-828. AStructure-ActivityRelationship for the Estimation of Rate Constants for the Gas-Phase Reactions of OH Radicals with Organic Compounds. Atkinson, R. (1987a). Environ. Sci. Technol. 

### 11, 305-307. Estimation of OH Radical Reaction Rate Constants and Atmospheric Lifetimes for Polychlorobiphenyls, Dibenzo-R-dioxins, and Dibenzofurans. Atkinson, R. (1988). Env. Toxic. and Chem. 

### 2, 435-442. Estimation of Gas-Phase Hydroxyl Radical Rate Constants for Organic Chemicals.

-127-Atkinson, R. (1987b, 1988a). In OECD (Organization for Economic Cooperation and Development) Test Guideline on Photochemical Oxidative Degradation in the Atmosphere. 1. Draft Final Report DatedJanuary, 1987b. Revision 2, p. 49- 113. 2. Draft Final Report DatedAugust, 1988a. Revision 3, p. 19-42 andAnnex III (Forty-eight examples are given for the estimation of the rate constants koH>· Umweltbundesamt Berlin, Bundesrepublik Deutschland. Estimation of OH Rate Constants. Atkinson, R. (1989). Monograph No. 1. Kinetics and Mechanisms of the Gas-Phase Reactions of the Hydroxyl Radical with Organic Compounds. American Chemical Society, Wash., D.C. andAmerican Inst. of Physics, New York, N.Y. Atkinson, R. (1989a). Unpublished Results. Updating of the Structure/ReactivityRelationships for the Reaction of OH Radicals with Organic Chemicals in the Gas-Phase. Atkinson, R.; Aschmann, S.M. (1984). Int. J. Chem. Kinet. 

### 1!, 1175-1186. Rate Constant for the Reaction of OH Radicals with a Series of Alkenes and Dialkenes at 295

### ± 1 K. Atkinson, R.; Aschmann, S.M. (1985). Environ. Sci. and Techno!.

**~,** 462-464. Rate Constants for the Gas-Phase Reaction of Hydroxyl Radicals with Biphenyl and theMonochlorobiphenyls at 295 ± 1 K. Atkinson, R.; Aschmann, S.M. (1986). Int. J. Chem. Kinet. 

### 11, 569-573. Kinetics of the Reaction of Naphthalene, 2-Methylnaphthalene, and 2,3-Dimethylnaphthalene with OH Radicals and with o3 at 295 

### ± 1 K. Atkinson, R.; Aschmann, S.M. (1987). Atmos. Environ. 

### 11, 2323-2326. Kinetics of the Gas-Phase Reactions of Alkylnaphthalenes with o3, N

2o5, andOH Radicals at 298 

### ± 2 K. Atkinson, R.; Aschmann, S.M. (1988). Int. J. Chem. Kinet. 1Q, 339-342. Rate constants for the Reaction of OH Radicals with Isopropylcyclopropane at 298

### ±2 K: Effects of Ring Strain on Substituted Cycloalkanes.

-128- " 

### """

i..T .,

**~**Atkinson, R.; Aschmann, S.M. (1988a). Int. J. Chem. Kinet. AQ, 513-539. Kinetics of the Reactions of Acenaphthalene and Structure-Related Aromatic Compounds with OH and N03 radicals, N205, and 03 at 296 

### ± 2 K. Atkinson, R.; Aschmann, S.M. (1989). Int. J. Chem. Kinet.**~,** 355-365. Rate constants for the Gas-Phase Reactions of the OH Radical with a Series of Aromatic Hydrocarbons at 296

### ±2 K. Atkinson, R.; Aschmann, S.M. (1989a). Int. J. Chem. Kinet.**~,** 1123-1129. Rate constants for the Reaction of the OH Radical with the Propyl and Butyl Nitrates and 1-Nitrobutane at 298 ± 2 K. Atkinson, R.; Carter, W.P.L. (1984). Chem. Rev. 

### ii, 437-470 Kinetics andMechanisms of the Gas-Phase Reactors of ozone with Organic Compounds Under Atmospheric Conditions. Atkinson, R.; Aschmann, S.M.; Carter, W.P.L. (1983). Int. J. Chem. Kinet. 

### 12, 1161-1177. Effects of Ring Strain on Gas-Phase Rate Constants; 2. OH Radical Reactions with cycloalkenes. Atkinson, R.; Aschmann, S.M.; carter, W.P.L. (1983a). Int. J. Chem. Kinet. 

### 12, 37-50. Rate constants for the Gas-Phase Reactions of OH Radicals with a Series of Bi- and Tricycloalkanes at 299 

### ± 2 K. Effects of Ring strain. Atkinson, R.; Aschmann, S.M.; carter, W.P.L. (1984a) Int. J. Chem. Kin• 

### .1§., 967-976. Kinetics of the Reactions of o3 and OH Radicals with a series of Dialkenes at 294 

### ± 2 K. Atkinson, R.; Aschmann, S.M.; Pitts, Jr., J.N. (1986). Int. J. Chem. Kinet. 

### 11, 287-299. Rate Constants for the Gas-Phase Reactions of the OH Radicals with a Series of Monoterpenes at 294 

### ± 1 K. Atkinson, R.; Perry, R.A.; Pitts, Jr., J.N. (1977). J. Chem. Phys. 

### ii, 1578-1581. Rate Constants for the Reaction of the OH Radical with CH3SH, CH3NH2 over the Temperature Range 299-426 K.

-129-Atkinson, R.; Perry, R.A.; Pitts, Jr., J.N. (1978). J. Chem. Phys., 1850-1853. Rate Constants for the Reactions of the OH Radical with (CH3)2NH, (CH3)3N, and c2H 5NH2 over the Temperature Range 298-426 K. Atkinson, R.; Aschmann, S.M.; Carter, W.P.L.; Pitts Jr., J.N. (1982). Int. J. Chem. Kinet. 

### 1!, 839-847. Rate Constants for the Gas-Phase Reaction of OH Radicals with a Series of Ketones at 299 

### ± 2 K. Atkinson, R.; Aschmann, S.M.; Carter, W.P.L.; Winer, A.M. (1982a). Int. J. Cham. Kinet. 

### 1!, 919-926. Kinetics of the Gas-Phase Reactions of OH Radicals with Alkyl Nitrates at 299 

### ± 2 K. Atkinson, R.; Aschmann, S.M.; Carter, W.P.L.; Winer, A.M.; Pitts Jr., J.N. (1982b). Int. J. Chem. Kinet•.

### l!, 781-788. Kinetics of the Reactions of OH Radicals withn-Alkanes at 299 

### ± 2 K. Atkinson, R.; carter, W.P.L.; Aschmann, S.M.; Winer, A.M.; Pitts Jr., J.N. (1984). Int. J. Chem. Kinet.**~'** 469-481. Kinetics of the Reactions of OH Radicals with a Series of Alkanes at 297 

### ± 2 K. Atkinson, R.; Aschmann, S.M.; Carter, W.P.L.; Winer, A.M.; Pitts Jr., J.N. (1984b). Int. J. Chem. Kinet.**~,** 1085-1101. Formation ofAlkyl Nitrates from the Reaction of Branched and CyclicAlkyl Peroxy Radicals with NO. Atkinson, R.; Aschmann, S.M.; Winer, A.M.; Pitts Jr., J.N. (1985a). Arch. Environ. Contam. Toxicol. 

### li, 417-425. Atmospheric Gas Phase Loss Processes for Chlorobenzene, Benzotrifluoride, and 4-Chlorobenzotrifluoride and Generalization of PredictiveTechniques for Atmospheric Losses of Aromatic compounds. Atkinson, R.; Tuazon, E.C.; Wallington, T.J.; Aschmann, S.M.; Arey, J.; Winer, A.M.; Pitts Jr., J.N. (1987). Environ. Sci. Technol. 

### 11, 64-72. Atmospheric Chemistry of Aniline, N,N-Dimethylaniline, Pyridine, 1,3,5-Triazine, and Nitrobenzene.

-130-

### r
Atkinson, R.; Aschmann, S.A.; Goodman, M.A.; Winer, A.M. (1988). Int. J. Chem. Kinet. lQ, 273-281. Kinetics of the Gas-Phase Reactions with the OH Radical with (C2H 5o)3P(O) and (CH3o)2P(S)Cl at 296 

### ± 2 K. Atkinson, R.; Baulch, D.L.; Cox, R.A.; Hampson Jr., R.F.; Kerr, J.A.; Troe, J. (1989a). Int. J. Chem. Kinet.

**~,** 115-150. Evaluated Kinetic and Photochemical Data for Atmospheric Chemistry: supplement III. Atkinson, R.; Aschmann, S.M.; Tuazon, E.C.; Arey, J.; Zillinska, B. (1989b). Int. J. Chem. Kinet.

**~,** 593-604. Formation of 3-Methylfuran from the Gas-Phase Reaction of OH Radicals with Isoprene and the Rate constant for its Reaction withOH Radicals. Atkinson, R.; Baulch, D.L.; Cox, R.A.; Hampson Jr., R.F., Kerr, J.A.; Troe, J. (1989c). J. Phys. Chem. Ref.

**Data~,** No. 2, 881-1097. Evaluated Kinetic and Photochemical Data for Atmospheric Chemistry, Supplement III. Atkinson, R.; Aschmann, S.M.; Arey, J.; Zielinska, B.; Schuetzles, D. (1989d). Atmos. Environ. 1}, 2679-2690. Gas-PhaseAtmospheric Chemistry of 1- and 2-Nitronaphthalene and 1,4-Naphthoquinone. Barnes, I.; Bastian, V.; Becker, K.H.; Fink, E.H.; Nelson, W. (1986). J. Atmos. Chem.

**~'** 445-446. Oxidation of Sulfur Compounds inthe Atmosphere: I. Rate Constants of OH Radical Reactions with Sulfur Dioxide, Hydrogen Sulfide, AliphaticThiols and Thiophenol. Barnes, I.; Bastian, V.; Becker, K.H. (1986a). Ninth International Symposium on Gas Kinetics, University of Bordeaux, Bordeaux France. July 20-25, 1986. D. Riedel Publishing Co. Dordrecht, Holland (1987). Baulch, D.L.; Campbell, I.M.; Saunders, S.M. (1985). Int. J. Chem. Kinet. 

### 11, 355-366. The rate constants for the reaction of thehydroxyl radical with methyl, n-propyl, andn-butyl nitrites. Baulch, D.L.; Campbell, I.M.; saunders, S.M. (1986). 9th International Symposium on Gas Kinetics 

## u. of Bordeaux, Bordeaux, France, July 20-25, 1986.
-131-Becker, K.H.; Bastian, V.; Klein, T.H. (1988). J. Photochem. Photobiol.; A: Chemistry 45, 195-205. The Reactions of OH Radicals with Toluene Diisocyanate, Toluenediamine, and Methylenediamine Under Simulated Atmospheric Conditions. Becker, K.H.; Biehl, H.M.; Bruckmann, P.; Fink, E.H.; FUbr, F.; Kloptfer, W.; Zellner, R.; Zetzsch, C. (November, 1984). Editors Kernforschungs anlage JUlick Gmblt. Bundesrepublik Deutschland. Report 1980-1983. Behnke, W.; Nolting, F.; Zetzsch, C. (1988). lOth International Symposium on Gas Kinetics (July 24-29, 1988) University of Swansea, swansea, U.K. Bennett, P.J.; Kerr, A. (1989). J. Atmos. Cham.**~,** 87-94. Kinetics of the Reactions of Hydroxyl Radicals with Aliphatic Ethers Studiedunder SimulatedAtmospheric Conditions. Biermann, H.W.; Macleod, H.; Atkinson, R.; Winer, A.M.; Pitts Jr., J.N. (1985). Environ. Sci. Techno!. 

### li, 244-248. Kinetics of the Gas-Phase Reactions of the Hydroxyl Radical with Naphthalene, Phenanthrene, and Anthracene. Bignozzi, A.; Maldotti, A.; Chiorboli, C.; Bartocci, C.; Carasitti,

## v. (1981). Int. J. Cham. Kinet. 

### 11, 1235-1242. Kinetics andMechanism of Reactions BetweenAromatic Olefins and Hydroxyl Radicals. Boodaghians, R.B.; Hell, I.W.; Toby, F.S.; Wayne, R.P. (1987). J. Cham. Soc. FaradayTrans. 

### 11, 2073- • Absolute Determinations of the Kinetics and Temperature Dependencies of the Reactions of OH with a Series of Alkynes. Brown, H.C. and Okamoto, Y. (1958). J. Am. Cham. Soc. iQ, 4979-4987. Electrophilic Substituent Constants. Campbell, I.M.; Parkinson, P.E. (1978). Chem. Phys. Lett. 2}, 385-387. Rate Constants for Reactions of Hydroxyl Radicals with Ester Vapors at 292 K. Chiorboli, C.; Bignozzi, C.A.; Maldotti, A.; Giardini, P.F.; Rossi, A.; Carassiti, 

## v. (1983). Int. J. Chem. Kinet. 

### 12, 579-586. Rate Constants for the Gas-Phase Reactions of OH Radicals with**~­** Dimethylstyrene NOx

- Air Photooxidation. -132-

# ,..

• '(I Clyne, M.A.A.; Holt, P.M. (1979). J. Chem. Soc. Faraday Trans. 

### A, 582-591. Reaction Kinetics Involving Ground x2" and Excited**A2~+** Hydroxyl Radicals. Cox, R.A.; Patrick, K.F.; Chant, S.A. (1981). Environ. Sci. Toxicol. 

### 12, 587-592. Mechanism of Atmospheric oxidation of Organic Compounds. Reactions of AlkoxyRadicals in Oxidation of n-Butane and Simple Ketones. Crutzen, D.J. (1982). In "Atmospheric Chemistry," D.G. Goldberg, Editor. The Global Distribution of Hydroxyl. pp. 313-328. Springer-Verlag, NY. Dagaut, P.; Wallington, T.J.; Liu, R.; Kurylo, M.J. (1988). J. Phys. Chem. 

### i1, 4375-4377. AKinetics Investigation of the Gas-Phase Reactions of OH Radicals with Cyclic Ketones and Diones: Mechanistic Insights.**Dag~ut,** P.; Wallington, T.J.; Liu, R.; Kurylo, M.J. (1988a). 22ng International Symposium on Combustion. Aug. 14-19, 1988. Seattle, WA. Darnall, K.R.; Winer, A.M.; Lloyd, A.C.; Pitts Jr., J.N. (1976). Chem. Phys. Letters !!, 415-418. Relative Rate Constants for the Reaction of OH Radicals with Selected c6 and c7 Alkanes and Alkenes at 305

### ±2 K. Davis, L.I.; James, J.V.; Wang, C.C.; Guo, C.; Morris, P.T.; Fishman, J. (1987). J. Geophys. Res. 

### il, 2020-2024. OH Measurement Near the Intertropical Convergence zone in the Pacific. Edney, E.O.; Kleindienst, T.E.; Corse, E.W. (1986). Int. J. Chem. Kinet. 

### li, 1355-1371. Room Temperature Rate constants for the Reaction of OH with Selected Chlorinated and Oxygenated Hydrocarbons. Felton, C.C.; Sheppard, J.C.; M.J. Campbell (1988). Nature

### 112, 53 (1988). Measurements of the Diurnal OH Cycle by a 14c-TracerMethod. Gaffney, J.S.; Levine, s.z. (1979). Int. J. Chem. Kinet. 

### 11, 1197-1209. Predicting Gas Phase OrganicMolecule Reaction Rates Using Linear Free Energy Correlations. I.o(3P) and OH Addition and Abstraction.
-133-Gaffney, J.S.; Fajer, R.; Senum, G.I.; Lee, J.H. (1986). Int. J. Chem. Kinet.**~,** 399-407. Measurement of the Reactivity of OH withMethyl Nitrite: Implications for Prediction of Alkyl Nitrate -OH Reaction Rates. Goodman, M.A.; Aschmann, S.M.; Atkinson, R.; Winer, A.M. (1988). Arch. Environ. Contam. Toxicol. 

### 11, 281-288. Kinetics of Atmospherically Important Gas-Phase Reactions of a Series of Trimethyl Phosphorothioates. Goodman, M.A.: Aschmann, S.M.; Atkinson, R.; Winer, A.M. (1988a). Env. Sci. Techno!.**~,** 578-583. Atmospheric Reactions of a Series of Dimethyl Phosphoroamidates and Dimethyl Phosphorothioamidates. Gorse, R.A.; Volman, D.H. (1974). J. Photochem.**~,** 115-122. Photochemistry of the Gaseous Hydrogen Peroxide-CarbonMonoxide System. II. Rate constants for Hydroxyl Radical Reactions with Hydrocarbons and for HydrogenAtom Reactions with Hydrogen Peroxide. Gorse, R.A.; Lii, R.R.; Saunders, B.B. (1977). Science

### lil, 1365-1367. Hydroxyl Radical Reactivity with Diethylhydroxylamine. Hard, T.M.; O'Brien, R.J.; Chan, C.Y.; Mehrabzadeh, A.A. (1984). Environ. Sci. Techno!. 

### 11, 768. Tropospheric Free Radical Determination by FAGE. Hard, T.M.; Chan, C.Y.; Mehrabzadeh, A.A.; Pan, W.H.; O'Brien, R.J. (1986).**Nature~,** 617 (1986). Diurnal Cycle of Tropospheric OH. Hansch, 

### c.; Leo, A. (1979). Substituent Constants for CorrelationAnalysis in Chemistry and Biology. J. Wiley and Sons, New York, NY. Harris, G.W.; Atkinson, R.; Pitts Jr., J.N. (1979). J. Phys. Chem. 

### 11, 2557-2559. Kinetics of the Reactions of the OH Radical with Hydrazine and Methylhydrazine. Harris, G.W.; Kleindienst, T.E.; PittsJr., J.N. (1981). Chem. Phys. Lett. iQ, 479-483. Rate Constants for the Reaction of OH Radicals with CH3CN, 

### c2H 5CN, and CH2=CHCN in the Temperature Range 298-424 K.

-134-t Harris, S.J.; Kerr, J.A. {1988). Int. J. Chem. Kinet. ZQ, 339. Hartmann, D.; Gedra, A.; Rhasa, D.; Zellner, R. (1987). Proceedinqs, 4thEuropeanSymposium onthe Physio-Chemical BehaviorofAtmosphericPollutants (1986). D. Riedel PublishinqCo., Dordrecht, Holland. p. 225. Hatakeyama, S.; Honda, S.; Washida, N.; Akimoto, H. (1985). Bull. Chem. Soc. Jpn. 

### 2i, 2157-2162. RateConstants andMechanism for Reactions ofKeteneswithOH Radicals inAir at 299 

### ± 2 K. Hatakeyama, S.; Washida, N.; Akimoto, H. (1986). J. Phys. Chem. iQ, 173-178. Rate Constants andMechanisms for theReactionofOH (OD) RadicalswithAcetylene, Propyne, and 2-Butyne inAir at 297

### ±2 

### K. Hendry, D.G.; Mill, ·T.; Davenport, J.E. (Auqust 1988). InOECO (Orqanizationfor Economic Cooperationand Development).
OECD TestGuideline on Photochemical Oxidative Deqradation inthe Atmosphere. DraftFinalReport, p. 14-43. January 1987. Umweltbundesamt BundesrepublikDeutschland, Berlin. Hewitt, C.W.; Harrison, R.M. (1985). Atmos. Environ. 

### li, 545-554. TroposphericConcentrations oftheHydroxylRadical -- AReview. Howard, 

## c.J. (1976). J. Chem. Phys. 

### §!, 4303-4306. Rate Constants for theReactions ofOH with Ethane and Some HalogenSubstitutedEthanes at 296 K. Howard, 

## c.J.; Evenson, K.M. (1976). J. Chem. Phys. 

### !!, 4303. Rate Constants for theReactions ofOH withEthane and Some Halogen SubstitutedEthanes at 296 K. HUbler, G.; Perner, D.; Platt, U.; Tonnissen, A.; Ehkalt, (1984). J. Geophys. Res. 

### !i, 1309-1319. Ground levelOH Radical Concentration: New Measurements by OpticalAbsorption. Hynes, A.J.; Wine, P.H.; semmes, O.H. (1986). J. Phys. Chem. iQ, 4148-4156. Kinetics andMechanisms ofOH Reactions withorqanic sulfides.

-135-Tuazon, E.C.; Atkinson, R.; carter, W.P.L. (1985). Environ. Sci. Technol.

**~'** 265-269. Atmospheric Chemistry of cis- and trans-3-Hexene-2,5-dione. Tuazon, E.C.; Atkinson, R.; Aschmann, S.M.; Arey, J.; Winer, A.M.; Pitts Jr., J.N. (1986). Environ. Sci. Techno!. ZQ, 1043-1046. Atmospheric Loss Process of 1,2-Dibromo-3-chloropropane and Trimethyl Phosphate. Tuazon, E.C.; Atkinson, R.; Aschmann, S.M.; Goodman, M.A.; Winer, A.M. (1988). J. Chem. Kinet.

**~'** 241-265. Atmospheric Chemistry of Chloroethenes with the OH Radical. Wahner, A.; Zetzsch, 

## c. (1983). J. Phys. Chem. 

### JZ, 4945-4951. Rate Constants for the Addition of OH to Aromatic (Benzene, R- Chloroaniline, and Q-, 

## m-, andR-Dichlorobenzene and the Unimolecular Decay of the Adduct. Kinetics into Quasi- Equilibrium). Wallington, T.J.; Kurylo, M.J. (1987). J. Phys. Chem.

**~'** 5050-5054. Flash Photolysis Resonance Fluorescence Investigation of the Gas- Phase Reactions of OH Radicals with a series of Aliphatic Ketones over the Temperature Range 240-440K. Wallington, T.J.; Kurylo, M.J. (1987a). Int. J. Chem. Kinet. 

### li, 1015-1023. The Gas Phase Reactions of Hydroxyl Radicals with a Series of AliphaticAlcohols Over the Temperature Range 240-440 K. Wallington, T.J.; Dagaut, P.; Liu, R.; Kurylo, M.J. (1988). Int. J. Chem. Kinet.

**~;** 177-186. The Gas Phase Reactions of Hydroxyl Radicals with a Series of Esters Over the Temperature Range 240-440 K. Wallington, T.J.; Liu, R.; Dagaut, P.; Kurylo, M.J. (1988a). Int. J. Chem. Kinet. 1Q, 41-49. The Gas Phase Reactions of Hydroxyl Radicals with a Series of Aliphatic Ethers over the Temperature Range 240-440 K. Wallington, T.J.; Dagaut, P.; Liu, R.; Kurylo, M.J. (1988b). Int. J. Chem. Kinet. 1Q, 541-547. Rate Constants for the Gas Phase Reactions of OH with c5 through c7 Aliphatic Alcohols and Ethers. Predicted and Experimental Values.

-140-Weast, R.C. (1976-1977). "Handbook of Chemistry and Physics" E-74. 57th Edition. Ionization Potentials of Molecules. CRC Press, Cleveland, Ohio. Winer, N.M.; Lloyd, A.C.; Darnall, K.R.; Pitts Jr., J.N. (1976). J. Phys. Chem. 80, 1635-1639. Relative Rate Constants for the Reaction of the Hydroxyl Radical with Selected Ketones, Chloroethenes, and Monoterpene Hydrocarbons. Witte, F.; Urbanik, E.; Zetzsch, 

### c. (1986). J. Phys. Chem. jQ, 3251-3259. Temperature Dependence of the Rate Constants for the Addition of OH to Benzene and Some MonosubstitutedAromatics (Aniline, Bromobenzene, and Nitrobenzene) and the Unimolecular Decay of the Adducts. Kinetics into a Quasi-Equilibrium. Wu, C.H.; Japar, S.M.; Niki, H. (1976). J. Environ. Sci. Health- Environ. Sci. Eng., All (2), 191-200. Relative Reactivities of HO-Hydrocarbon Reactions from Smog Reactor Studies. Zabarnick, S.; Fleming, J.W.; Lin, M.C. (1988). Int. J. Chem. Kinet.**~'** 117-129. Kinetics of Hydroxyl Radical Reactions with Formaldehyde and 1,3,5-Trioxanebetween 290 and 600 K. Zabarnick, S.; Fleming, J.W.; Lin, M.C. (1988a). Chem. Phys. 11Q, 319-325. The Reaction of OH and OD with Nitromethane. Zetzsch, 

### c. (1980). Bunsen Colloquium, G8ttingen, 

## w. Germany, October 9, 1980. zetzsch, 

### c. (1982). Report to Bundesminister fUr Forschung undTechnologie, Projektrager fUr Umweltchemikalien. Bundesrepublik Deutschland.

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