Boiling Point (Range) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-O; 64742-83-2; 68333-88-O; 68476-45-9; 68478-l O4; 68516-20-I; 68527-23-l; 68919-15-3 

Robust Summary No.: OP E660 

LOW BENZENE NAPHTHAS ROBUST SUMMARY 

Boiling Point 

; 68333-88-O; 68476-45-9; 68478-10-4; 68516-20-I; 

8527-23-l; 6891915-31 

Test Conditions: Boiling Point is calculated by the MPBPWIN subroutine, which is 

based on the calculation method of S. Stein and R. Brown in 

. Note: Concentration prep., “Estimation of Normal Boiling Points from Group Contributions”. 

vessel type, replication, test 1994. J. Chem. Inf. Comput. Sci. 34: 581-587. 

conditions. 

Units/Value: 

. Note: Deviations from 

substances represented by the 10 CAS numbers under Test 

protocol or guideline, 

Substance. Substances in this category do not have a specific 

analytical method. boiling point value. Actual boiling point ranges for substances in 

this category will vary dependent on their constituent composition. 

Commercial substances in this category consist of complex 

hydrocarbon reaction products with a carbon number distribution 

that is predominantly C5-C12. The seven chemicals selected to 

represent the boiling point range of this category are C5-Cl1 

hydrocarbons that can be found in substances identified by the 10 

CAS numbers. Constituents representing category members were 

selected on the basis of carbon number as identified by the 

category name, chemistry/structure, measured boiling point ranges 

for category substances, and olefinic process (distillation) 

Page 1 of3 
Boiling Point (Range) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-

4; 68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E660 

Results: (continued) Substance Calculated Measured* 

Constituent BP (°C) BP (°C) Units/Value: 

isopentane 30.18 27.8 Note: Deviations from protocol or toluene 125.72 110.6 guideline, analytical method. m-xylene 

styrene 

naphthalene 

tricyclodecane 

methylnaphthalene 

148.29 139.1 

146.65 145.0 

231.64 217.9 

171.25 na 

249.60 241.1 

* Experimental values from EPIWIN database.

na = not available 

The data represent a potential boiling point range for substances 

represented by the 10 CAS numbers under Test Substance. 

Test Substance: The Low Benzene Naphthas Category includes the following CAS 

numbers: 

64741-98-6 Extract, petroleum, heavy naphtha solvent 

64742-48-9 Naphtha, petroleum, hydrotreated heavy 

64742-49-0 Naphtha, petroleum, hydrotreated light 

64742-83-2 Naphtha, petroleum, light steam-cracked 

68333-88-0 Aromatic hydrocarbons, C9-C17 

68476-45-9 Hydrocarbons, C5-10 aromatic concentration, 

ethylene-manufacture-by-product 

68478-10-4 Naphtha, petroleum, light steam-cracked, 

debezenized, C8-16-cycloalkadiene concentrate 

68516-20-1 Naphtha, petroleum, steam-cracked middle aromatic 

68527-23-1 Naphtha, petroleum, light steam-cracked aromatic 

68919-15-3 Hydrocarbons, C6-12, benzene-recovery 

Low Benzene Naphthas Category substances arise from 

production processes associated with ethylene manufacturing. 

The 10 CAS numbers are used to describe the nine process 

streams arising from the ethylene process and other associated 

manufacturing processes. The category includes hydrocarbon 

product streams associated with the ethylene industry. Aromatics 

represent the major constituents in all of the streams, varying from 

approximately 45 to 95 percent. The benzene content is usually 

less than five percent. 

More information on the Low Benzene Naphthas Category can be 

found in the American Chemistry Council, Olefins Panel test plan 

for this category (1). 

1. Olefins Panel, HPV Implementation Task Group. 2001. High 

Production Volume (HPV) Chemical Challenge Program Test 

Plan For The Low Benzene Naphthas Category. American 

Chemistry Council, Olefins Panel, HPV Implementation Task 

Group. VA, USA. 

Page 2 of 3 
Boiling Point (Range) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-

4; 68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E660 

Conclusion: The calculated boiling points for some representative constituents 

that are present in the category streams vary from 30.18 to 

249.60°C @ 760 mm Hg. The measured boiling points of these 

same constituents vary from 27.8 to 241.1°C @ 760 mm Hg. 

Although this does not define the actual boiling points of the 

category streams, it offers an indication of a range that might be 

expected to encompass the boiling points of these complex 

streams with variable compositions. Boiling points outside these 

ranges may be possible for some category streams. 

Reliability: (2) Reliable with restrictions 

The results include calculated data based on chemical structure as 

modeled by EPIWIN and measured data for specific chemicals as 

cited in the EPIWIN database. The data represent a potential 

boiling point range for substances represented by the 10 CAS 

numbers listed under Test Substance. This robust summary has a 

reliability rating of 2 because the data are not for specific 

substances in Low Benzene Naphthas Category, but rather for 

selected constituents. These selected constituents represent all 

substances defined by this category and as such, this robust 

summary represents a "key study" for boiling point range based on 

constituent data. 

Reference: EPIWIN. 1999. Estimation Program Interface for Windows, version 

3.04. Syracuse Research Corporation, Syracuse, NY, USA. 

(Boiling point values were calculated by the MPBPWIN subroutine 

and measured data came from the database in the computer 

program.) 

Other (source): American Chemistry Council, Olefins Panel (Prepared 7/03) 

* Other TS is a selection option under the Test Substance pick list that is in the IUCLID entry field 

for Boiling Point. Selecting this option refers the reader to information in the test substance 

"freetext" field to which the CAS numbers can be added. 

Page 3 of 3 
Hydrolysis (Stability in Water) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-4; 

68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E667 

LOW BENZENE NAPHTHAS ROBUST SUMMARY 

Hydrolysis (Stability in Water) 

Test Substance*: Other TS [CAS # 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 

68333-88-0; 68476-45-9; 68478-10-4; 68516-20-1; 68527-23-

1; 68919-15-3] 

Method/Guideline: Other: Technical discussion 

Year (guideline): Not applicable 

Type (test type): Not applicable 

GLP (Y/N): Not applicable 

Year (study performed): Not applicable 

Analytical Monitoring: Not applicable 

Test Conditions: Not applicable 

• Note: Concentration 

preparation, vessel type, 

volume, replication, 

deviations from 

guideline or protocol 

Results: Not applicable 

Units/Value: 

• Note: Analytical method, 

observations, half-lives 

by pH, degradation 

products 

Test Substance: The Low Benzene Naphthas Category includes the following CAS 

numbers: 

64741-98-6 Extract, petroleum, heavy naphtha solvent 

64742-48-9 Naphtha, petroleum, hydrotreated heavy 

64742-49-0 Naphtha, petroleum, hydrotreated light 

64742-83-2 Naphtha, petroleum, light steam-cracked 

68333-88-0 Aromatic hydrocarbons, C9-C17 

68476-45-9 Hydrocarbons, C5-10 aromatic concentration, ethylenemanufacture-by-product 

68478-10-4 Naphtha, petroleum, light steam-cracked, debezenized, 

C8-16-cycloalkadiene concentrate 

68516-20-1 Naphtha, petroleum, steam-cracked middle aromatic 

68527-23-1 Naphtha, petroleum, light steam-cracked aromatic 

68919-15-3 Hydrocarbons, C6-12, benzene-recovery 

Page 1 of 6 
Hydrolysis (Stability in Water) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-4; 

68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E667 

Low Benzene Naphthas Category substances arise from production 

processes associated with ethylene manufacturing. The 10 CAS 

numbers are used to describe the nine process streams arising from 

the ethylene process and other associated manufacturing processes. 

The category includes hydrocarbon product streams associated with 

the ethylene industry. Aromatics represent the major constituents in all 

of the streams, varying from approximately 45 to 95 percent. The 

benzene content is usually less than five percent. 

More information on the Low Benzene Naphthas Category can be found 

in the American Chemistry Council, Olefins Panel test plan for this 

category (1). 

1. Olefins Panel, HPV Implementation Task Group. 2001. High 

Production Volume (HPV) Chemical Challenge Program Test Plan 

For The Low Benzene Naphthas Category. American Chemistry 

Council, Olefins Panel, HPV Implementation Task Group. VA, 

USA. 

Conclusion: Summary 

In the environment, hydrolysis will not contribute to the degradation of 

constituent chemicals in the Low Benzene Naphthas Category. The 

Low Benzene Naphthas Category includes nine process streams: 

• Pyrolysis C7s Fraction 

• Pyrolysis C7-C12 Fraction 

• Pyrolysis C7-C8 Fraction 

• C9+ From Xylene Unit 

• Hydrotreated C8-C10 Fraction 

• Hydrotreated C7-C12 Fraction 

• Hydrotreated C7+ Fraction 

• Hydrotreated C5/C9 blend 

• Toluene Extract 

Ten CAS numbers (see Test Substance) identify products derived from 

these process streams. As discussed below, the chemicals in these 

streams are composed of carbon and hydrogen and are not amenable 

to hydrolysis because of their molecular structure and the chemical 

reaction required for this type of transformation to occur. 

The Low Benzene Naphthas Category 

A process stream is a mixture of chemicals that arises from a chemical 

reaction or separation activity. The category includes hydrocarbon 

product streams associated with the ethylene industry. Aromatics 

represent the major constituents in all of the streams, varying from 

approximately 45 to 95 percent. The benzene content is usually less 

than five percent. This grouping of CAS numbers represents 

hydrocarbon streams with a carbon number distribution that is 

predominantly C5-C12. That is why this group is considered a 

category for purposes of the High Production Volume (HPV) Chemical 

Program, and designated Low Benzene Naphthas. 

Page 2 of 6 
Hydrolysis (Stability in Water) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-4; 

68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E667 

The definitions found in the TSCA Chemical Substance Inventory for 

the CAS numbers included in this group are vague with respect to 

composition. Therefore, it is possible to find that the same CAS 

number is correctly used to describe different streams (compositions) 

or that two or more different CAS numbers are used to describe the 

same stream (composition or process). 

More information on the Low Benzene Naphthas Category can be 

found in the American Chemistry Council, Olefins Panel test plan for 

this category (1). The plan is available on the U.S. Environmental 

Protection Agency website under the HPV Chemical Program. A brief 

description of the production and composition of the nine process 

streams in this category are: 

• Pyrolysis Fractions (C7s, C7-C12, and C7-C8 Fractions) are 

separated by distillation into various boiling-point range fractions 

as intermediates in preparation for further processing. Many 

carbon number distribution fractions are technically feasible. The 

compositions of these fractions vary depending on the ethylene 

process feedstock, the cracking furnaces operating conditions 

and the ethylene process configuration. 

1. Pyrolysis C7s Fraction has a carbon number distribution 

that is 75% toluene with the balance primarily C7 nonaromatics, largely unsaturates. The stream may contain low 

levels of benzene. 

2. Pyrolysis C7-C12 Fraction has a typical composition 

including about 2% benzene, 23% toluene, 28% C8 

aromatics and 8% naphthalene, with the balance expected 

to be largely unsaturated hydrocarbons and other aromatics. 

3. Pyrolysis C7-C8 Fraction has a carbon number distribution 

that is predominantly C7 to C8. The reported compositions 

range from 45 to 80% with 11 to 78% C8 aromatics. The 

typical benzene concentration reported is 2% with a 

maximum of 5%. 

• C9+ from Xylene Unit is a co-product from process units that 

produce o- or p-xylene. The carbon distribution for the stream is 

C8+ with some hydrocarbon compounds having a boiling point of 

650°F or higher. The stream is predominantly aromatics. 

• Hydrotreated Pyrolysis Fractions (C8-C10, C7-C12, C7+ 

Fractions, and C5/C9 Blend) are pyrolysis gasoline or distillate 

fractions of pyrolysis gasoline that are treated with hydrogen over 

catalyst. The hydrogenation process may be either one-stage or 

two-stage. The one-stage process is typically a liquid-phase 

process where the primary objective is to selectively convert 

diolefins to mono-olefins and to convert vinyl aromatics, for 

example, styrene to ethylbenzene. The second stage in a twostage hydrogenation process is typically a vapor-phase, more 

severe hydrogenation that converts essentially all of the 

contained mono- and diolefins to paraffins. A pygas fraction that 

Page 3 of 6 
Hydrolysis (Stability in Water) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-4; 

68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E667 

will be processed by extraction or extractive distillation to produce 

high purity aromatics (toluene or xylenes in this case) is subjected 

to two-stage hydrogenation. Pygas fractions may be forwarded to 

hydrodealkylation units (less common) for benzene production 

after one-stage of hydrogenation. Pygas fractions intended for 

use as a gasoline blending stock are frequently subject to only 

one-stage hydrogenation. The streams may result from 

fractionation of hydrotreated pyrolysis gasoline or from 

hydrotreating pyrolysis gasoline fractions followed by distillation. 

Reformate fractions from petroleum refineries are sometimes 

mixed with these pyrolysis fractions. 

1. Hydrotreated C8-C10 Fraction has a carbon number 

distribution of C6 to C12, but is predominantly C8 to C10. 

Typical concentration includes 0.3% benzene, 2.4% 

toluene, 24% C8 aromatics with the balance primarily C9 

and C10 aromatics and lesser amounts of paraffins, 

isoparaffins and naphthenes in this carbon range. 

2. Hydrotreated C7-C12 Fraction is a distillate fraction of 

hydrogenated pygas with a carbon number distribution that 

is predominantly C7-C12, with lesser amounts of C6. 

Typical reported values indicate 1% benzene, 23% toluene, 

25% C8 aromatics, with the balance primarily other 

aromatics and lesser amounts of monoolefins and paraffins. 

3. Hydrotreated C7+ Fraction is derived as distillation 

residue after removing the C5 and C6 fractions from a 

hydrogenated pygas stream (alternately the stream could 

be hydrotreated after distillation). The carbon number 

distribution is predominantly greater than C6, although the 

reported analysis does not report compounds greater than 

C12. Typical reported values include 23% toluene, 32% C8 

aromatics, 1% naphthalene, with the balance primarily 

other aromatics and lesser amounts of paraffins. 

4. Hydrotreated C5/C9 Blend is produced by blending C5 

and C9 pyrolysis fractions, hydrogenated either before or 

after blending. Typical reported values includes 

approximately 2% benzene, 40% C5's in the blend, 9% C8 

aromatics, 19% C9 aromatics, and 25% C10+. 

• Toluene Extract is produced as a co-product of a benzene 

extraction unit. The stream may contain significant 

concentrations of xylenes. 

Page 4 of 6 
Hydrolysis (Stability in Water) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-4; 

68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E667 

Hydrolysis of Hydrocarbons as a Function of Molecular Structure 

with water (H2

nucleophilic substitution reaction, where X is the leaving group being 

replaced by the incoming nucleophilic oxygen from the water molecule. 

The leaving group, X, must be a molecule other than carbon because 

The carbon atom lacks sufficient electronegativity to be a good leaving 

alkenes, are not subject to hydrolysis (3) and this fate process will not 

contribute to the degradative loss of chemical components in this 

category from the environment. 

react with water by an addition reaction mechanism (2). The reaction 

product is an alcohol. This reaction is not considered to be hydrolysis 

reaction is freely reversible (3). Substances that have a potential to 

hydrolyze include alkyl halides, amides, carbamates, carboxylic acid 

esters and lactones, epoxides, phosphate esters, and sulfonic acid 

esters (4). 

olefins that contain at least one double bond (alkenes). The remaining 

chemicals are saturated hydrocarbons (alkanes). These two groups of 

chemicals contain only carbon and hydrogen. As such, their molecular 

Therefore, chemicals in the Low Benzene Naphthas Category have a 

very low potential to hydrolyze, and this degradative process will not 

contribute to their removal in the environment. 

Production Volume (HPV) Chemical Challenge Program Test Plan 

For The Low Benzene Naphthas Category. American Chemistry 

Council, Olefins Panel, HPV Implementation Task Group. VA, 

USA. 

Chemistry, Holt, Reinhart and Winston, New York, NY, USA. 

Lyman, W.F. Reehl, and D.H. Rosenblatt, eds., Handbook of 

Company, New York, NY, USA. 

CRC Press, Boca Raton, FL, USA. 

Hydrolysis of an organic molecule occurs when a molecule (R-X) reacts 

O) to form a new carbon-oxygen bond after the carbon-X 

bond is cleaved (2,3). Mechanistically, this reaction is referred to as a 

for hydrolysis to occur, the R-X bond cannot be a carbon-carbon bond. 

group and carbon-carbon bonds are too stable (high bond energy) to be 

cleaved by nucleophilic substitution. Thus, hydrocarbons, including 

Under strongly acidic conditions the carbon-carbon double bond found 

in alkenes, such as those in the Low Benzene Naphthas Category, will 

because the carbon-carbon linkage is not cleaved and because the 

The substances in the Low Benzene Naphthas Category are primarily 

structure is not subject to the hydrolytic mechanism discussed above. 

References 

1. Olefins Panel, HPV Implementation Task Group. 2001. High 

2. Gould, E.S. (1959), Mechanism and Structure in Organic 

3. Harris, J.C. (1982), "Rate of Hydrolysis," Chapter 7 in: W.J. 

Chemical Property Estimation Methods, McGraw-Hill Book 

4. Neely, W. B. 1985. Hydrolysis. In: W. B. Neely and G. E. Blau, 

eds. Environmental Exposure from Chemicals. Vol I., pp. 157-173. 

Page 5 of 6 
Hydrolysis (Stability in Water) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-4; 

68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E667 

Reliability: These data represent a key study for characterizing the potential of 

substances in the Low Benzene Naphthas Category to undergo 

hydrolysis. 

Reference: American Chemistry Council, Olefins Panel. 2003. Hydrolysis Low 

Benzene Naphthas Category. Rosslyn, VA, USA. 

Other (source): American Chemistry Council, Olefins Panel (Prepared 7/03) 

* Other TS is a selection option under the Test Substance pick list that is in the IUCLID entry field for 

Hydrolysis. Selecting this option refers the reader to information in the test substance "freetext" field to 

which the CAS numbers can be added. 

Page 6 of 6 
Melting Point (Range) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-

4; 68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E661 

LOW BENZENE NAPHTHAS ROBUST SUMMARY 

Melting Point 

Test Substance*: Other TS [CAS # 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-

2; 68333-88-0; 68476-45-9; 68478-10-4; 68516-20-1; 

68527-23-1; 68919-15-3] 

Method/Guideline: Calculated values using MPBPWIN version 1.40, a subroutine of 

the computer program EPIWIN version 3.04 

Year (guideline): 1999 

Type (test type): Not applicable 

GLP: Not applicable 

Year (study performed): Not applicable 

Test Conditions: Melting Point is calculated by the MPBPWIN subroutine, which is 

based on the average result of the methods of K. Joback and Gold 

• Note: Concentration prep., and Ogle. 

vessel type, replication, test 

conditions. Joback's Method is described in Joback, K.G. 1982. A Unified 

Approach to Physical Property Estimation Using Multivariate 

Statistical Techniques. In The Properties of Gases and Liquids. 

Fourth Edition. 1987. R.C. Reid, J.M. Prausnitz and B.E. Poling, 

Eds. 

The Gold and Ogle Method simply uses the formula 

Tm = 0.5839Tb, where Tm is the melting point in Kelvin and Tb is 

the boiling point in Kelvin. The Gold and Ogle Method is described 

by Lyman, W.J., 1985, In: Environmental Exposure from 

Chemicals. Volume 1. Neely, W.B. and Blau, G.E. (eds), Boca 

Raton, FL, CRC Press, Inc., Chapter 2. 

Results: Calculated and measured melting point data for representative 

constituents of the Low Benzene Naphthas Category are listed 

Units/Value: below. The data identify a potential melting point range for 

• Note: Deviations from 

protocol or guideline, 

analytical method. 

substances represented by the 10 CAS numbers under Test 

Substance. Substances in this category do not have a specific 

melting point value. Actual melting point ranges for substances in 

this category will vary dependent on their constituent composition. 

Commercial substances in this category consist of complex 

hydrocarbon reaction products with a carbon number distribution 

that is predominantly C5-C12. The seven chemicals selected to 

represent the melting point range of this category are C5-C11 

hydrocarbons that can be found in substances identified by the 10 

CAS numbers. Constituents representing category members were 

selected on the basis of carbon number as identified by the 

category name, chemistry/structure, measured boiling point ranges 

for category substances, and olefinic process (distillation) 

knowledge. 

Page 1 of 3 
Melting Point (Range) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-

4; 68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E661 

Results: (continued) Substance Calculated Measured* 

Constituent MP (°C) MP (°C) 

Units/Value: 

isopentane -119.04 -159.9 

Note: Deviations from protocol or toluene -59.17 -94.9 

guideline, analytical method. m-xylene 

styrene 

naphthalene 

tricyclodecane 

methylnaphthalene 

-40.69 -47.8 

-48.31 -31.0 

5.01 80.2 

-19.15 na 

22.15 34.4 

* Experimental values from EPIWIN database. 

na = not available 

The data represent a potential melting point range for substances 

represented by the 10 CAS numbers under Test Substance. 

Test Substance: The Low Benzene Naphthas Category includes the following CAS 

numbers: 

64741-98-6 Extract, petroleum, heavy naphtha solvent 

64742-48-9 Naphtha, petroleum, hydrotreated heavy 

64742-49-0 Naphtha, petroleum, hydrotreated light 

64742-83-2 Naphtha, petroleum, light steam-cracked 

68333-88-0 Aromatic hydrocarbons, C9-C17 

68476-45-9 Hydrocarbons, C5-10 aromatic concentration, 

ethylene-manufacture-by-product 

68478-10-4 Naphtha, petroleum, light steam-cracked, 

debezenized, C8-16-cycloalkadiene concentrate 

68516-20-1 Naphtha, petroleum, steam-cracked middle aromatic 

68527-23-1 Naphtha, petroleum, light steam-cracked aromatic 

68919-15-3 Hydrocarbons, C6-12, benzene-recovery 

Low Benzene Naphthas Category substances arise from 

production processes associated with ethylene manufacturing. 

The 10 CAS numbers are used to describe the nine process 

streams arising from the ethylene process and other associated 

manufacturing processes. The category includes hydrocarbon 

product streams associated with the ethylene industry. Aromatics 

represent the major constituents in all of the streams, varying from 

approximately 45 to 95 percent. The benzene content is usually 

less than five percent. 

More information on the Low Benzene Naphthas Category can be 

found in the American Chemistry Council, Olefins Panel test plan 

for this category (1). 

1. Olefins Panel, HPV Implementation Task Group. 2001. High 

Production Volume (HPV) Chemical Challenge Program Test 

Plan For The Low Benzene Naphthas Category. American 

Chemistry Council, Olefins Panel, HPV Implementation Task 

Group. VA, USA. 

Page 2 of 3 
Melting Point (Range) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-

4; 68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E661 

Conclusion: The calculated melting points for some representative 

constituents that are present in the category streams vary from -

119.04 to 22.15 °C. The measured melting points of these same 

constituents vary from -159.9 to 80.2°C. Although this does not 

define the actual melting points of the category streams, it offers 

an indication of a range that might be expected to encompass the 

melting points of these complex streams with variable 

compositions. Melting points outside these ranges may be 

possible for some category streams. 

Reliability: (2) Reliable with restrictions 

The results include calculated data based on chemical structure as 

modeled by EPIWIN and measured data for specific chemicals as 

cited in the EPIWIN database. The data represent a potential 

melting point range for substances represented by the 10 CAS 

numbers listed under Test Substance. This robust summary has a 

reliability rating of 2 because the data are not for specific 

substances in the Low Benzene Naphthas Category, but rather for 

selected constituents. These selected constituents represent all 

substances defined by this category and as such, this robust 

summary represents a "key study" for melting point range based 

on constituent data. 

Reference: EPIWIN. 1999. Estimation Program Interface for Windows, version 

3.04. Syracuse Research Corporation, Syracuse, NY, USA. 

(Melting point values were calculated by the MPBPWIN subroutine 

and measured data came from the database in the computer 

program.) 

Other (source): American Chemistry Council, Olefins Panel (Prepared 7/03) 

* Other TS is a selection option under the Test Substance pick list that is in the IUCLID entry field 

for Melting Point. Selecting this option refers the reader to information in the test substance 

"freetext" field to which the CAS numbers can be added. 

Page 3 of 3 
Partition Coefficient (Range) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-

4; 68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E663 

LOW BENZENE NAPHTHAS ROBUST SUMMARY 

Partition Coefficient 

Test Substance*: Other TS [CAS # 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-

2; 68333-88-0; 68476-45-9; 68478-10-4; 68516-20-1; 

68527-23-1; 68919-15-3] 

Method/Guideline: Calculated values using KOWWIN version 1.65, a subroutine of 

the computer program EPIWIN version 3.04 

Year (guideline): 1999 

Type (test type): Not applicable 

GLP: Not applicable 

Year (study performed): Not applicable 

Estimation Temperature: 25°C 

Test Conditions: Octanol / Water Partition Coefficient is calculated by the KOWWIN 

subroutine, which is based on an atom/fragment contribution 

• Note: Concentration prep., method of W. Meylan and P. Howard in "Atom/fragment 

vessel type, replication, test contribution method for estimating octanol-water partition 

conditions. coefficients". 1995. J. Pharm. Sci. 84:83-92. 

Results: 

Units/Value: 

• Note: Deviations from 

protocol or guideline, 

analytical method. 

Calculated and measured log Kow data for representative 

constituents of the Low Benzene Naphthas Category are listed 

below. The data identify a potential log Kow range for substances 

represented by the 10 CAS numbers under Test Substance. 

Substances in this category do not have a specific log Kow value. 

Actual log Kow ranges for substances in this category will vary 

dependent on their constituent composition. 

Commercial substances in this category consist of complex 

hydrocarbon reaction products with a carbon number distribution 

that is predominantly C5-C12. The seven chemicals selected to 

represent the log Kow range of this category are C5-C11 

hydrocarbons that can be found in substances identified by the 10 

CAS numbers listed under Test Substance. Constituents 

representing category members were selected on the basis of 

carbon number as identified by the category name, 

chemistry/structure, measured boiling point ranges for category 

substances, and olefinic process (distillation) knowledge. 

Page 1 of 3 
Partition Coefficient (Range) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-

4; 68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E663 

Results: (continued) Substance Calculated Measured* 

Constituent log Kow @ 25°C log Kow @ 25°C 

Units/Value: 

isopentane 2.72 na 

Note: Deviations from protocol or toluene 2.54 2.73 

guideline, analytical method. m-xylene 

styrene 

naphthalene 

tricyclodecane 

methylnaphthalene 

3.09 3.20 

2.89 2.95 

3.17 3.30 

3.59 na 

3.72 3.86 

* Experimental values from EPIWIN database. 

na = not available 

The data represent a potential log Kow range for substances 

represented by the 10 CAS numbers under Test Substance. 

Test Substance: The Low Benzene Naphthas Category includes the following CAS 

numbers: 

64741-98-6 Extract, petroleum, heavy naphtha solvent 

64742-48-9 Naphtha, petroleum, hydrotreated heavy 

64742-49-0 Naphtha, petroleum, hydrotreated light 

64742-83-2 Naphtha, petroleum, light steam-cracked 

68333-88-0 Aromatic hydrocarbons, C9-C17 

68476-45-9 Hydrocarbons, C5-10 aromatic concentration, 

ethylene-manufacture-by-product 

68478-10-4 Naphtha, petroleum, light steam-cracked, 

debezenized, C8-16-cycloalkadiene concentrate 

68516-20-1 Naphtha, petroleum, steam-cracked middle aromatic 

68527-23-1 Naphtha, petroleum, light steam-cracked aromatic 

68919-15-3 Hydrocarbons, C6-12, benzene-recovery 

Low Benzene Naphthas Category substances arise from 

production processes associated with ethylene manufacturing. 

The 10 CAS numbers are used to describe the nine process 

streams arising from the ethylene process and other associated 

manufacturing processes. The category includes hydrocarbon 

product streams associated with the ethylene industry. Aromatics 

represent the major constituents in all of the streams, varying from 

approximately 45 to 95 percent. The benzene content is usually 

less than five percent. 

More information on the Low Benzene Naphthas Category can be 

found in the American Chemistry Council, Olefins Panel test plan 

for this category (1). 

1. Olefins Panel, HPV Implementation Task Group. 2001. High 

Production Volume (HPV) Chemical Challenge Program Test 

Plan For The Low Benzene Naphthas Category. American 

Chemistry Council, Olefins Panel, HPV Implementation Task 

Group. VA, USA. 

Page 2 of 3 
Partition Coefficient (Range) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-

4; 68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E663 

Conclusion: The calculated log Kow for some representative constituents that 

are present in the category streams vary from 2.54 to 3.72 @ 

25°C. The measured log Kow of these same constituents vary 

from 2.73 to 3.86 @ 25°C. Although this does not define the 

actual log Kow of the category streams, it offers an indication of a 

range that might be expected to encompass the log Kow of these 

complex streams with variable compositions. Log Kow values 

outside these ranges may be possible for some category streams. 

Reliability: (2) Reliable with restrictions 

The results include calculated data based on chemical structure as 

modeled by EPIWIN and measured data for specific chemicals as 

cited in the EPIWIN database. The data represent a potential log 

Kow range for substances represented by the 10 CAS numbers 

under Test Substance. This robust summary has a reliability rating 

of 2 because the data are not for specific substances in the Low 

Benzene Naphthas Category, but rather for selected constituents. 

These selected constituents represent all substances defined by 

this category and as such, this robust summary represents a "key 

study" for log Kow range based on constituent data. 

Reference: EPIWIN. 1999. Estimation Program Interface for Windows, version 

3.04. Syracuse Research Corporation, Syracuse, NY, USA. (Log 

Kow values were calculated by the KOWWIN subroutine and 

measured data came from the database in the computer program.) 

Other (source): American Chemistry Council, Olefins Panel (Prepared 7/03) 

* Other TS is a selection option under the Test Substance pick list that is in the IUCLID entry field 

for Partition Coefficient. Selecting this option refers the reader to information in the test substance 

"freetext" field to which the CAS numbers can be added. 

Page 3 of 3 
Photodegradation (Direct) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-4; 

68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E668 

LOW BENZENE NAPHTHAS ROBUST SUMMARY 

Photodegradation (Direct) 

Test Substance*: Other TS [CAS # 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 

68333-88-0; 68476-45-9; 68478-10-4; 68516-20-1; 68527-23-

1; 68919-15-3] 

Method/Guideline: Other: Technical discussion 

Year (guideline): Not applicable 

GLP (Y/N): Not applicable 

Year (study performed): Not applicable 

Type (air, soil, water, other): Water 

Light Source: Not applicable 

Light Spectrum: Not applicable 

• Wave length value 

(upper/lower) 

Relative Intensity: Not applicable 

Test Substance Spectrum: Not applicable 

Test Conditions: Not applicable 

• Note: Concentration, 

temperature, test system 

type, replication, 

deviations from 

guideline or protocol 

Direct Photolysis**: 

• Results: half-life, % 

degradation, quantum 

yield 

Summary 

In the environment, direct photolysis will not significantly contribute to 

the degradation of constituent chemicals in the Low Benzene Naphthas 

Category. The Low Benzene Naphthas Category includes nine process 

streams: 

• Pyrolysis C7s Fraction 

• Pyrolysis C7-C12 Fraction 

• Pyrolysis C7-C8 Fraction 

• C9+ From Xylene Unit 

• Hydrotreated C8-C10 Fraction 

• Hydrotreated C7-C12 Fraction 

• Hydrotreated C7+ Fraction 

• Hydrotreated C5/C9 blend 

• Toluene Extract 

Page 1 of 6 
Photodegradation (Direct) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-4; 

68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E668 

these process streams. As discussed below, the reaction process 

involved in direct photolysis occurs when sufficient light energy excites 

a molecule to the degree that a structural transformation occurs. In 

chemicals that will undergo direct photolysis. 

The Low Benzene Naphthas Category 

A process stream is a mixture of chemicals that arises from a chemical 

reaction or separation activity. The category includes hydrocarbon 

product streams associated with the ethylene industry. Aromatics 

represent the major constituents in all of the streams, varying from 

approximately 45 to 95 percent. The benzene content is usually less 

than five percent. 

hydrocarbon streams with a carbon number distribution that is 

That is why this group is considered a 

category for purposes of the High Production Volume (HPV) Chemical 

the CAS numbers included in this group are vague with respect to 

composition. Therefore, it is possible to find that the same CAS 

number is correctly used to describe different streams (compositions) 

or that two or more different CAS numbers are used to describe the 

same stream (composition or process). 

More information on the Low Benzene Naphthas Category can be 

found in the American Chemistry Council, Olefins Panel test plan for 

Protection Agency website under the HPV Chemical Program. A brief 

description of the production and composition of the nine process 

streams in this category are: 

• are 

as intermediates in preparation for further processing. Many 

carbon number distribution fractions are technically feasible. The 

process feedstock, the cracking furnaces operating conditions 

and the ethylene process configuration. 

1. Pyrolysis C7s Fraction has a carbon number distribution 

The stream may contain 

low levels of benzene. 

2. has a typical composition 

including about 2% benzene, 23% toluene, 28% C8 

aromatics and 8% naphthalene, with the balance expected 

aromatics. 

Ten CAS numbers (see Test Substance) identify products derived from 

general, substances in this category do not contain component 

This grouping of CAS numbers represents 

predominantly C5-C12. 

Program, and designated Low Benzene Naphthas. 

The definitions found in the TSCA Chemical Substance Inventory for 

this category (1). The plan is available on the U.S. Environmental 

Pyrolysis Fractions (C7s, C7-C12, and C7-C8 Fractions) 

separated by distillation into various boiling-point range fractions 

compositions of these fractions vary depending on the ethylene 

that is 75% toluene with the balance primarily C7 nonaromatics, largely unsaturates. 

Pyrolysis C7-C12 Fraction 

to be largely unsaturated hydrocarbons and other 

Page 2 of 6 
Photodegradation (Direct) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-4; 

68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E668 

3. Pyrolysis C7-C8 Fraction has a carbon number 

distribution that is predominantly C7 to C8. The reported 

compositions range from 45 to 80% with 11 to 78% C8 

aromatics. The typical benzene concentration reported is 

2% with a maximum of 5%. 

• C9+ from Xylene Unit is a co-product from process units that 

produce o- or p-xylene. The carbon distribution for the stream is 

C8+ with some hydrocarbon compounds having a boiling point of 

650°F or higher. The stream is predominantly aromatics. 

• Hydrotreated Pyrolysis Fractions (C8-C10, C7-C12, C7+ 

Fractions, and C5/C9 Blend) are pyrolysis gasoline or distillate 

fractions of pyrolysis gasoline that are treated with hydrogen over 

catalyst. The hydrogenation process may be either one-stage or 

two-stage. The one-stage process is typically a liquid-phase 

process where the primary objective is to selectively convert 

diolefins to mono-olefins and to convert vinyl aromatics, for 

example, styrene to ethylbenzene. The second stage in a twostage hydrogenation process is typically a vapor-phase, more 

severe hydrogenation that converts essentially all of the 

contained mono- and diolefins to paraffins. A pygas fraction that 

will be processed by extraction or extractive distillation to produce 

high purity aromatics (toluene or xylenes in this case) is subjected 

to two-stage hydrogenation. Pygas fractions may be forwarded to 

hydrodealkylation units (less common) for benzene production 

after one-stage of hydrogenation. Pygas fractions intended for 

use as a gasoline blending stock are frequently subject to only 

one-stage hydrogenation. The streams may result from 

fractionation of hydrotreated pyrolysis gasoline or from 

hydrotreating pyrolysis gasoline fractions followed by distillation. 

Reformate fractions from petroleum refineries are sometimes 

mixed with these pyrolysis fractions. 

1. Hydrotreated C8-C10 Fraction has a carbon number 

distribution of C6 to C12, but is predominantly C8 to C10. 

Typical concentration includes 0.3% benzene, 2.4% 

toluene, 24% C8 aromatics with the balance primarily C9 

and C10 aromatics and lesser amounts of paraffins, 

isoparaffins and naphthenes in this carbon range. 

2. Hydrotreated C7-C12 Fraction is a distillate fraction of 

hydrogenated pygas with a carbon number distribution that 

is predominantly C7-C12, with lesser amounts of C6. 

Typical reported values indicate 1% benzene, 23% toluene, 

25% C8 aromatics, with the balance primarily other 

aromatics and lesser amounts of monoolefins and 

paraffins. 

3. Hydrotreated C7+ Fraction is derived as distillation 

residue after removing the C5 and C6 fractions from a 

hydrogenated pygas stream (alternately the stream could 

Page 3 of 6 
Photodegradation (Direct) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-4; 

68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E668 

be hydrotreated after distillation). The carbon number 

distribution is predominantly greater than C6, although the 

C12. Typical reported values include 23% toluene, 32% 

C8 aromatics, 1% naphthalene, with the balance primarily 

other aromatics and lesser amounts of paraffins. 

4. Hydrotreated C5/C9 Blend is produced by blending C5 

after blending. Typical reported values includes 

approximately 2% benzene, 40% C5's in the blend, 9% C8 

aromatics, 19% C9 aromatics, and 25% C10+. 

• Toluene Extract

extraction unit. The stream may contain significant 

concentrations of xylenes. 

Photolysis of Hydrocarbons 

The direct photolysis of an organic molecule occurs when it absorbs 

sufficient light energy to result in a structural transformation (2). The 

reaction process is initiated when light energy in a specific wavelength 

range elevates a molecule to an electronically excited state. However, 

the excited state is competitive with various deactivation processes that 

nm, can result in the electronic excitation of an organic molecule. Light 

in this range contains energy of the same order of magnitude as 

infrared) result only in vibrational and rotational transitions, which do 

not tend to produce structural changes to a molecule. 

The stratospheric ozone layer prevents UV light of less than 290 nm 

between 290 and 750 nm can result in photochemical transformations 

excited molecule by mechanisms other than chemical transformation, 

resulting in no change to the parent molecule. 

rate is to assume that degradation will occur in proportion to the amount 

of light wavelengths >290 nm absorbed by the molecule (3). Saturated 

hydrocarbons do not absorb light above 200 nm. Some characteristic 

absorbance maxima (lmax e) for 

selected unsaturated hydrocarbons are shown below (2): 

reported analysis does not report compounds greater than 

and C9 pyrolysis fractions, hydrogenated either before or 

 is produced as a co-product of a benzene 

can result in the return of the molec ule to a non excited state. 

The absorption of light in the ultra violet (UV)-visible range, 110-750 

covalent bond dissociation energies (2). Higher wavelengths (e.g. 

from reaching the earth's surface. Therefore, only light at wavelengths 

in the environment (2). Although the absorption of UV light in the 290­

750 nm range is necessary, it is not always sufficient for a chemical to 

undergo photochemical degradation. Energy may be re-emitted from an 

A conservative approach to estimating a photochemical degradation 

) and associated molar absorptivities (

Page 4 of 6 
Photodegradation (Direct) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-4; 

68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E668 

l below 290 nm l above 290 nm 

Hydrocarbon lmax e lmax e 

Ethylene 193 10,000 - -

Benzene 255 215 - -

Styrene 244 12,000 - -

282 450 

Naphthalene 221 100,000 311 250 

270 5,000 

Olefins with one double bond, or two conjugated double bonds, which 

constitute the majority of the chemicals in the Low Benzene Naphthas 

category, do not absorb appreciable light energy above 290 nm. The 

absorption of UV light to cause cis-trans isomerism about the double 

bond of an olefin occurs only if it is in conjugation with an aromatic ring 

(2). 

Products in the Low Benzene Naphthas Category do not contain 

component molecules that will undergo direct photolysis. Therefore, this 

fate process will not contribute to a measurable degradative removal of 

chemical components in this category from the environment. 

References 

1. Olefins Panel, HPV Implementation Task Group. 2001. High 

Production Volume (HPV) Chemical Challenge Program Test Plan 

For The Low Benzene Naphthas Category. American Chemistry 

Council, Olefins Panel, HPV Implementation Task Group. VA, USA. 

2. Harris, J. C. 1982. "Rate of Aqueous Photolysis," Chapter 8 in: W. 

J. Lyman, W. F. Reehl, and D. H. Rosenblatt, eds., Handbook of 

Chemical Property Estimation Methods, McGraw-Hill Book 

Company, New York, USA. 

3. Zepp, R. G. and D. M. Cline. 1977. Rates of Direct Photolysis in the 

Aqueous Environment, Environ. Sci. Technol., 11:359-366. 

Indirect Photolysis**: Not applicable 

• Results: type of 

sensitizer, concentration 

of sensitizer, rate 

constant, % degradation, 

half-life 

Degradation Products**: Unknown 

• Note: Identification, 

concentration 

Page 5 of 6 
Photodegradation (Direct) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-4; 

68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E668 

Test Substance: The Low Benzene Naphthas Category includes the following CAS 

numbers: 

64741-98-6 Extract, petroleum, heavy naphtha solvent 

64742-48-9 Naphtha, petroleum, hydrotreated heavy 

64742-49-0 Naphtha, petroleum, hydrotreated light 

64742-83-2 Naphtha, petroleum, light steam-cracked 

68333-88-0 Aromatic hydrocarbons, C9-C17 

68476-45-9 Hydrocarbons, C5-10 aromatic concentration, ethylenemanufacture-by-product 

68478-10-4 Naphtha, petroleum, light steam-cracked, debezenized, 

C8-16-cycloalkadiene concentrate 

68516-20-1 Naphtha, petroleum, steam-cracked middle aromatic 

68527-23-1 Naphtha, petroleum, light steam-cracked aromatic 

68919-15-3 Hydrocarbons, C6-12, benzene-recovery 

Conclusion: Not applicable 

Reliability: These data represent a key study for characterizing the potential of 

substances in the Low Benzene Naphthas Category to undergo direct 

photodegradation. 

Reference: American Chemistry Council, Olefins Panel. 2003. Photodegradation 

(Direct): Low Benzene Naphthas Category. Rosslyn, VA, USA. 

Other (source): American Chemistry Council, Olefins Panel (Prepared 7/03) 

* Other TS is a selection option under the Test Substance pick list that is in the IUCLID entry field for 

Photodegradation (Direct). Selecting this option refers the reader to information in the test substance 

"freetext" field to which the CAS numbers can be added. 

Page 6 of 6 
Photodegradation (Indirect) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-

4; 68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E670 

LOW BENZENE NAPHTHAS ROBUST SUMMARY 

Photodegradation (Indirect) 

Test Substance*: Other TS [CAS # 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-

2; 68333-88-0; 68476-45-9; 68478-10-4; 68516-20-1; 

68527-23-1; 68919-15-3] 

Method/Guideline: Calculated values using AOPWIN version 1.89, a subroutine of the 

computer program EPIWIN version 3.04 

Year (guideline): 1999 

GLP (Y/N): Not applicable 

Year (study performed): Not applicable 

Type (air, soil, water, other): Not applicable 

Light Source: Sunlight 

Light Spectrum: 

• Wave length value 

(upper/lower) 

Natural sunlight 

Relative Intensity: 1 

Test Substance Spectrum: Not applicable 

Test Conditions: 

• Note: Concentration, 

temperature, test system 

type, replication, deviations 

from guideline or protocol 

Indirect photodegradation, or atmospheric oxidation potential, is 

based on the structure-activity relationship methods developed by 

R. Atkinson. 

Temperature: 25°C 

Sensitizer: OH radical 

Concentration of Sensitizer: 1.5 E6

 OH radicals/cm3 

Direct Photolysis**: 

Results: half-life, % degradation, Not applicable 

quantum yield 

Page 1 of 4 
Photodegradation (Indirect) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-

4; 68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E670 

Indirect Photolysis**: The Low Benzene Naphthas Category 

• Results: type of sensitizer, Low Benzene Naphthas Category substances arise from 

concentration of sensitizer, production processes associated with ethylene manufacturing. rate constant, % degradation, The 10 CAS numbers are used to describe nine process streams half-life arising from the ethylene process and other associated 

manufacturing processes. The category includes hydrocarbon 

product streams associated with the ethylene industry. Aromatics 

represent the major constituents in all of the streams, varying from 

approximately 45 to 95 percent. The benzene content is usually 

less than five percent. 

Commercial substances in this category consist of both high purity 

hydrocarbons and complex hydrocarbon reaction products with a 

carbon number distribution that is predominantly C5-C11. That is 

why this group is considered a category for purposes of the High 

Production Volume (HPV) Chemical Program, and designated Low 

Benzene Naphthas. 

The seven chemicals selected to represent the atmospheric 

oxidation potential of this category are C5-C11 hydrocarbons that 

can be found in substances identified by the 10 CAS numbers. 

Constituents representing category members were selected on the 

basis of carbon number as identified by the category name, 

chemistry/structure, measured boiling point ranges for category 

substances, and olefinic process (distillation) knowledge. 

Atmospheric Oxidation of Hydrocarbons 

In the environment, organic chemicals emitted into the troposphere 

are degraded by several important transformation processes. The 

dominant transformation process for most compounds is the 

daylight reaction with hydroxyl (OH-) radicals (Atkinson, 1988, 

1989). The rate at which an organic compound reacts with OHradicals is a direct measure of its atmospheric persistence (Meylan 

and Howard, 1993). 

AOPWIN estimates the rate constant for the atmospheric, gasphase reaction between photochemically produced hydroxyl 

radicals and organic chemicals. The rate constants estimated by 

the program are then used to calculate atmospheric half-lives for 

organic compounds based upon average atmospheric 

concentrations of hydroxyl radicals. 

Since the reactions only take place in the presence of sunlight, the 

atmospheric half-lives are normalized for a 12-hour day. 

Page 2 of 4 
Photodegradation (Indirect) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-

4; 68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E670 

Indirect Photolysis**: (cont'd) Calculated* OH- Rate Constant 

Chemical half-life (hrs) (cm3/molecule-sec) Results: type of sensitizer, 

concentration of sensitizer, rate isopentane 31.8 4.0 E-12 

constant, % degradation, half-life toluene 

m-xylene 

styrene 

naphthalene 

tricyclodecane 

methylnaphthalene 

24.6 5.2 E-12 

9.5 13.6 E-12 

4.6 28.1 E-12 

5.9 21.6 E-12 

5.6 22.9 E-12 

2.3 56.5 E-12 

* Atmospheric half-life values are based on a 12-hr day. 

More information on the Low Benzene Naphthas Category can be 

found in the American Chemistry Council, Olefins Panel test plan 

for this category (Olefins Panel, 2001). 

References: 

1. Atkinson, R. 1988. Estimation of gas-phase hydroxyl radical 

rate constants for organic chemicals. Environ. Toxicol. Chem. 

7:435-442. 

2. Atkinson, R. 1989. Kinetics and mechanisms of the gasphase reactions of the hydroxyl radical with organic 

compounds. J. Phys. Chem. Ref. Data Monograph No. 1, 

Amer. Inst. Physics & Amer. Chem. Soc., NY. 

3. Meylan, W.M. and P.H. Howard. 1993. Computer estimation 

of the atmospheric gas-phase reaction rate of organic 

compounds with hydroxyl radicals and ozone. Chemosphere 

12:2293-2299. 

4. Olefins Panel, HPV Implementation Task Group. 2001. High 

Production Volume (HPV) Chemical Challenge Program Test 

Plan For The Low Benzene Naphthas Category. American 

Chemistry Council, Olefins Panel, HPV Implementation Task 

Group. VA, USA. 

Degradation Products**: Unknown 

• Note: Identification, 

concentration 

Page 3 of 4 
Photodegradation (Indirect) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-

4; 68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E670 

Test Substance: The Low Benzene Naphthas Category includes the following CAS 

numbers: 

64741-98-6 Extract, petroleum, heavy naphtha solvent 

64742-48-9 Naphtha, petroleum, hydrotreated heavy 

64742-49-0 Naphtha, petroleum, hydrotreated light 

64742-83-2 Naphtha, petroleum, light steam-cracked 

68333-88-0 Aromatic hydrocarbons, C9-C17 

68476-45-9 Hydrocarbons, C5-10 aromatic concentration, 

ethylene-manufacture-by-product 

68478-10-4 Naphtha, petroleum, light steam-cracked, 

debezenized, C8-16-cycloalkadiene concentrate 

68516-20-1 Naphtha, petroleum, steam-cracked middle aromatic 

68527-23-1 Naphtha, petroleum, light steam-cracked aromatic 

68919-15-3 Hydrocarbons, C6-12, benzene-recovery 

Conclusion: Atmospheric oxidation via hydroxyl radicals can be a significant 

route of degradation for products in this category. Based on 

calculated values, products in this category can have an 

atmospheric half-life range of 2.3 to 31.8 hours as a result of 

indirect photolysis by hydroxyl radical attack. 

Reliability: (2) Reliable with restrictions 

The results include calculated data based on chemical structure as 

modeled by AOPWIN. The data represent a potential atmospheric 

half-life range for substances represented by the 10 CAS numbers 

under Test Substance. This robust summary has a reliability rating 

of 2 because the data are not for specific substances in the Low 

Benzene Naphthas Category, but rather for selected constituents. 

These selected constituents represent all substances defined by 

this category and as such, this robust summary represents a "key 

study" for atmospheric half-life range based on constituent data. 

Reference: Meylan, M., SRC 1994-1999. AOPWIN is contained in the 

computer program EPIWIN. 1999. Estimation Program Interface 

for Windows, version 3.04. Syracuse Research Corporation, 

Syracuse, NY, USA. 

Other (source): American Chemistry Council, Olefins Panel (Prepared 10/03) 

* Other TS is a selection option under the Test Substance pick list that is in the IUCLID entry field 

for Photodegradation (Indirect). Selecting this option refers the reader to information in the test 

substance "freetext" field to which the CAS numbers can be added. 

** In IUCLID, provide additional discussion if needed in the results freetext

Page 4 of 4 
Transport / Distribution (Fugacity) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-

4; 68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E669 

LOW BENZENE NAPHTHAS ROBUST SUMMARY 

Transport / Distribution (Fugacity) 

Test Substance*: Other TS [CAS # 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-

2; 68333-88-0; 68476-45-9; 68478-10-4; 68516-20-1; 

68527-23-1; 68919-15-3] 

Method/Guideline: Calculated according to Mackay Level I, EQC Model version 1.01 

Year (guideline): 1997 

Type (test type): Not applicable 

GLP: Not applicable 

Year (study performed): Not applicable 

Estimation Temperature: 25°C 

Test Conditions: The EQC Level I is a steady state, equilibrium model that utilizes 

the input of basic chemical properties including molecular weight, 

• Note: Concentration prep., 

vessel type, replication, test 

conditions. 

vapor pressure, and water solubility to calculate distribution within 

a standardized regional environment. 

Physicochemical input values for the model were calculated using 

the EPIWIN Estimation v 3.04 program (1). Measured input values 

were also used where available and obtained from the EPIWIN 

database (1). Distribution data from the equilibrium model provide 

basic information on the potential partitioning behavior of 

chemicals between selected environmental compartments (i.e., air, 

water, soil, sediment, suspended sediment, biota). 

1. EPIWIN. 1999. Estimation Program Interface for Windows, 

version 3.04. Syracuse Research Corporation, Syracuse, NY, 

USA. 

Page 1 of 4 
Transport / Distribution (Fugacity) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-

4; 68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E669 

Results: 

Units/Value: 

• Note: Deviations from 

protocol or guideline, 

analytical method. 

Calculated partitioning data for representative constituents of the 

The data 

identify a potential distribution for substances represented by the 

. Actual distribution of 

substances in this category will vary dependent on their 

constituent composition. 

hydrocarbon reaction products with a carbon number distribution 

The seven chemicals selected to 

represent the environmental distribution range of this category are 

by the 10 CAS numbers. Constituents representing category 

members were selected on the basis of carbon number as 

identified by the category name, chemistry/structure, measured 

(distillation) knowledge. 

The range of distribution data for constituent chemicals in each of 

the compartments can be used as an estimate of the partitioning 

behavior for category substances. 

representative constituents of substances in this category were 

determined using physicochemical input data calculated using the 

EPIWIN program: 

Calculated* 

Percent Distribution 

Chemical Air Water Soil Sediment 

isopentane 0.01 0.01 -

toluene 98.17 1.40 0.43 -

97.19 1.33 1.45 0.03 

styrene 95.55 2.61 1.80 0.04 

naphthalene 24.47 32.28 42.28 0.94 

tricyclodecane 98.68 0.29 1.01 0.02 

methylnaphthalene 97.68 0.40 1.88 0.04 

EPIWIN program 

Low Benzene Naphthas Category are listed below. 

10 CAS numbers under Test Substance

Commercial substances in this category consist of complex 

that is predominantly C5-C12. 

C5-C11 hydrocarbons that can be found in substances identified 

boiling point ranges for category substances, and olefinic process 

The following Mackay Level I model distribution values for 

99.98 

m-xylene 

* Distribution values determined using calculated input data from 

Page 2 of 4 
Transport / Distribution (Fugacity) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-

4; 68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E669 

Results: (cont'd) 

Units/Value: 

• Note: Deviations from 

protocol or guideline, 

analytical method. 

Measured** 

Percent Distribution 

Chemical Air Water Soil Sediment 

Isopentane 99.98 0.01 0.01 -

toluene 98.80 0.81 0.39 -

97.91 0.86 1.20 0.03 

styrene 96.65 1.85 1.46 0.04 

naphthalene 42.27 20.56 36.33 0.81 

tricyclodecane na na na na 

methylnaphthalene 98.53 0.19 1.25 0.03 

** Distribution values determined using measured input data from 

na = not available 

Test Substance: The Low Benzene Naphthas Category includes the following CAS 

numbers: 

Extract, petroleum, heavy naphtha solvent 

Naphtha, petroleum, hydrotreated heavy 

production processes associated with ethylene manufacturing. 

The 10 CAS numbers are used to describe the nine process 

streams arising from the ethylene process and other associated 

manufacturing processes. The category includes hydrocarbon 

Aromatics 

represent the major constituents in all of the streams, varying from 

approximately 45 to 95 percent. The benzene content is usually 

less than five percent. 

found in the American Chemistry Council, Olefins Panel test plan 

for this category (1). 

1. Olefins Panel, HPV Implementation Task Group. 2001. High 

Production Volume (HPV) Chemical Challenge Program Test 

American 

Chemistry Council, Olefins Panel, HPV Implementation Task 

Group. VA, USA. 

m-xylene 

the EPIWIN program experimental database. 

64741-98-6 

64742-48-9 

64742-49-0 Naphtha, petroleum, hydrotreated light 

64742-83-2 Naphtha, petroleum, light steam-cracked 

68333-88-0 Aromatic hydrocarbons, C9-C17 

68476-45-9 Hydrocarbons, C5-10 aromatic concentration, 

ethylene-manufacture-by-product 

68478-10-4 Naphtha, petroleum, light steam-cracked, 

debezenized, C8-16-cycloalkadiene concentrate 

68516-20-1 Naphtha, petroleum, steam-cracked middle aromatic 

68527-23-1 Naphtha, petroleum, light steam-cracked aromatic 

68919-15-3 Hydrocarbons, C6-12, benzene-recovery 

Low Benzene Naphthas Category substances arise from 

product streams associated with the ethylene industry. 

More information on the Low Benzene Naphthas Category can be 

Plan For The Low Benzene Naphthas Category. 

Page 3 of 4 
Transport / Distribution (Fugacity) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-

4; 68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E669 

Conclusion: The partitioning data represent a potential distribution range for 

substances in the 10 CAS numbers listed under Test Substance. 

Substances in the Low Benzene Naphthas Category are 

calculated to partition primarily to air with a negligible percentage 

partitioning to water, soil, and sediment. Relatively high vapor 

pressure and high water solubility largely control the partitioning 

behavior of constituent chemicals in substances from this 

category. 

The input data used to run the EQC Level I model included 

estimated values calculated by the EPIWIN program based on 

chemical structure and measured data from the EPIWIN database. 

A comparison of the distribution data developed using either all 

calculated input values or measured values where data were 

available indicate a similar partitioning behavior and support the 

use of the dataset for chemicals without any measured data. 

Reliability: (2) Reliable with restrictions 

The input data used to run the EQC Level I model include 

calculated and experimental values available through the EPIWIN 

program. The data represent a potential environmental distribution 

range for substances with the 10 CAS numbers listed under Test 

Substance. This robust summary has a reliability rating of 2 

because the data are not for specific substances in the Low 

Benzene Naphthas Category, but rather for selected constituents. 

These selected constituents represent all substances defined by 

this category and as such, this robust summary represents a "key 

study" for distribution range based on constituent data. 

Reference: Mackay, D.A. DiGuardo, S. Paterson, and C. Cowan. EQC Model 

Version 1.01. 1997. Available from the Environmental Modeling 

Centre, Trent University, Canada. 

Other (source): American Chemistry Council, Olefins Panel (Prepared 7/03) 

* Other TS is a selection option under the Test Substance pick list that is in the IUCLID entry field 

for Transport-Distribution. Selecting this option refers the reader to information in the test 

substance "freetext" field to which the CAS numbers can be added. 

Page 4 of 4 
Vapor Pressure (Range) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-

4; 68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E662 

LOW BENZENE NAPHTHAS ROBUST SUMMARY 

Vapor Pressure 

Test Substance*: Other TS [CAS # 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-

2; 68333-88-0; 68476-45-9; 68478-10-4; 68516-20-1; 

68527-23-1; 68919-15-3] 

Method/Guideline: Calculated values using MPBPWIN version 1.40, a subroutine of 

the computer program EPIWIN version 3.04 

Year (guideline): 1999 

Type (test type): Not applicable 

GLP: Not applicable 

Year (study performed): Not applicable 

Estimation Temperature: 25°C 

Test Conditions: 

• Note: Concentration prep., 

vessel type, replication, test 

conditions. 

Vapor Pressure is calculated by the MPBPWIN subroutine, which 

is based on the average result of the methods of Antoine and 

Grain. Both methods use boiling point for the calculation. 

The Antoine Method is described in the Handbook of Chemical 

Property Estimation. Chapter 14. W.J. Lyman, W.F. Reehl and 

D.H. Rosenblatt, Eds. Washington, D.C.: American Chemical 

Society. 1990. 

A modified Grain Method is described on page 31 of Neely and 

Blau's Environmental Exposure from Chemicals, Volume 1, CRC 

Press. 1985. 

Results: Calculated and measured vapor pressure data for representative 

constituents of the Low Benzene Naphthas Category are listed 

Units/Value: below. The data identify a potential vapor pressure range for 

• Note: Deviations from 

protocol or guideline, 

analytical method. 

substances represented by the 10 CAS numbers under Test 

Substance. Substances in this category do not have a specific 

vapor pressure value. Actual vapor pressure ranges for 

substances in this category will vary dependent on their 

constituent composition. 

Commercial substances in this category consist of complex 

hydrocarbon reaction products with a carbon number distribution 

that is predominantly C5-C12. The seven chemicals selected to 

represent the vapor pressure range of this category are C5-C11 

hydrocarbons that can be found in substances identified by the 10 

CAS numbers. Constituents representing category members were 

selected on the basis of carbon number as identified by the 

category name, chemistry/structure, measured boiling point ranges 

for category substances, and olefinic process (distillation) 

knowledge. 

Page 1 of 3 
Vapor Pressure (Range) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-

4; 68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E662 

Results (continued): 

Units/Value: 

Note: Deviations from protocol or 

guideline, analytical method. 

Substance Calculated VP Measured* VP 

Constituent (hPa @ 25°C) (hPa @ 25°C) 

isopentane 9.17 E2 9.19 E2 

toluene 31.60 37.86 

8.83 11.05 

styrene 6.73 8.53 

naphthalene 0.11 0.05 

tricyclodecane 2.64 na 

methylnaphthalene 

na = not available 

The data represent a potential vapor pressure range for 

Substance. 

Test Substance: The Low Benzene Naphthas Category includes the following CAS 

numbers: 

Naphtha, petroleum, hydrotreated heavy 

Naphtha, petroleum, hydrotreated light 

Low Benzene Naphthas Category substances arise from 

production processes associated with ethylene manufacturing. 

The 10 CAS numbers are used to describe the nine process 

manufacturing processes. The category includes hydrocarbon 

product streams associated with the ethylene industry. Aromatics 

represent the major constituents in all of the streams, varying from 

The benzene content is usually 

less than five percent. 

More information on the Low Benzene Naphthas Category can be 

found in the American Chemistry Council, Olefins Panel test plan 

for this category (1). 

1. 

Production Volume (HPV) Chemical Challenge Program Test 

Plan For The Low Benzene Naphthas Category. American 

Chemistry Council, Olefins Panel, HPV Implementation Task 

Group. VA, USA. 

m-xylene 

4.60 E-2 7.33 E-2 

* Experimental values from EPIWIN database. 

substances represented by the 10 CAS numbers under Test 

64741-98-6 Extract, petroleum, heavy naphtha solvent 

64742-48-9 

64742-49-0 

64742-83-2 Naphtha, petroleum, light steam-cracked 

68333-88-0 Aromatic hydrocarbons, C9-C17 

68476-45-9 Hydrocarbons, C5-10 aromatic concentration, 

ethylene-manufacture-by-product 

68478-10-4 Naphtha, petroleum, light steam-cracked, 

debezenized, C8-16-cycloalkadiene concentrate 

68516-20-1 Naphtha, petroleum, steam-cracked middle aromatic 

68527-23-1 Naphtha, petroleum, light steam-cracked aromatic 

68919-15-3 Hydrocarbons, C6-12, benzene-recovery 

streams arising from the ethylene process and other associated 

approximately 45 to 95 percent. 

Olefins Panel, HPV Implementation Task Group. 2001. High 

Page 2 of 3 
Vapor Pressure (Range) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-

4; 68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E662 

Conclusion: The calculated vapor pressures for some representative 

constituents that are present in the category streams vary from 

4.60 E-2 to 9.17 E2 hPa @ 25°C. The measured vapor pressures 

of these same constituents vary from 7.33 E-2 to 9.19 E2 hPa @ 

25°C. Although this does not define the actual vapor pressures of 

the category streams, it offers an indication of a range that might 

be expected to encompass the vapor pressures of these complex 

streams with variable compositions. Vapor pressure outside 

these ranges may be possible for some category streams. 

Reliability: (2) Reliable with restrictions 

The results include calculated data based on chemical structure as 

modeled by EPIWIN and measured data for specific chemicals as 

cited in the EPIWIN database. The data represent a potential 

vapor pressure range for substances represented by the 10 CAS 

numbers under Test Substance. This robust summary has a 

reliability rating of 2 because the data are not for specific 

substances in the Low Benzene Naphthas Category, but rather for 

selected constituents. These selected constituents represent all 

substances defined by this category and as such, this robust 

summary represents a "key study" for vapor pressure range based 

on constituent data. 

Reference: EPIWIN. 1999. Estimation Program Interface for Windows, version 

3.04. Syracuse Research Corporation, Syracuse, NY, USA. (Vapor 

pressure values were calculated by the MPBPWIN subroutine and 

measured data came from the database in the computer program.) 

Other (source): American Chemistry Council, Olefins Panel (Prepared 7/03) 

* Other TS is a selection option under the Test Substance pick list that is in the IUCLID entry field 

for Vapor Pressure. Selecting this option refers the reader to information in the test substance 

"freetext" field to which the CAS numbers can be added. 

Page 3 of 3 
Water Solubility (Range) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-

4; 68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E664 

LOW BENZENE NAPHTHAS ROBUST SUMMARY 

Water Solubility 

Test Substance*: Other TS [CAS # 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-

2; 68333-88-0; 68476-45-9; 68478-10-4; 68516-20-1; 

68527-23-1; 68919-15-3] 

Method/Guideline: Calculated values using WSKOWWIN version 1.36, a subroutine 

of the computer program EPIWIN version 3.04 

Year (guideline): 1999 

Type (test type): Not applicable 

GLP: Not applicable 

Year (study performed): Not applicable 

Estimation Temperature: 25°C 

Test Conditions: Water Solubility is calculated by the WSKOWWIN subroutine, 

which is based on a Kow correlation method described by W. 

• Note: Concentration prep., Meylan, P. Howard and R. Boethling in "Improved method for 

vessel type, replication, test estimating water solubility from octanol/water partition coefficient". 

conditions. Environ. Toxicol. Chem. 15:100-106. 1995. 

Results: 

Units/Value: 

• Note: Deviations from 

protocol or guideline, 

analytical method. 

Calculated and measured water solubility data for representative 

constituents of the Low Benzene Naphthas Category are listed 

below. The data identify a potential water solubility range for 

substances represented by the 10 CAS numbers under Test 

Substance. Substances in this category do not have a specific 

water solubility value. Actual water solubility ranges for 

substances in this category will vary dependent on their loading 

rate (i.e., weight of test material added to a volume of water). 

Commercial substances in this category consist of complex 

hydrocarbon reaction products with a carbon number distribution 

that is predominantly C5-C12. The seven chemicals selected to 

represent the water solubility range of this category are C5-C11 

hydrocarbons that can be found in substances identified by the 10 

CAS numbers. Constituents representing category members were 

selected on the basis of carbon number as identified by the 

category name, chemistry/structure, measured boiling point ranges 

for category substances, and olefinic process (distillation) 

knowledge. 

Page 1 of 3 
Water Solubility (Range) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-

4; 68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E664 

Results: (continued) 

Units/Value: 

Note: Deviations from protocol or 

guideline, analytical method. 

Substance Calculated WS Measured WS* 

Constituent (mg/L @ 25°C) (mg/L @ 25°C) 

isopentane 184.6 na 

toluene 832.7 573.1 

258.4 207.2 

styrene 386.7 343.7 

naphthalene 183.8 142.1 

tricyclodecane 21.5 na 

methylnaphthalene 54.6 41.4 

* Experimental values from EPIWIN database. 

na = not available 

The data represent a potential water solubility range for 

Substance. 

The Low Benzene Naphthas Category includes the following CAS 

numbers: 

Extract, petroleum, heavy naphtha solvent 

Naphtha, petroleum, hydrotreated heavy 

Naphtha, petroleum, hydrotreated light 

Low Benzene Naphthas Category substances arise from 

The 10 CAS numbers are used to describe the nine process 

streams arising from the ethylene process and other associated 

manufacturing processes. The category includes hydrocarbon 

Aromatics 

represent the major constituents in all of the streams, varying from 

approximately 45 to 95 percent. The benzene content is usually 

less than five percent. 

More information on the Low Benzene Naphthas Category can be 

for this category (1). 

1. Olefins Panel, HPV Implementation Task Group. 2001. High 

Production Volume (HPV) Chemical Challenge Program Test 

Plan For The Low Benzene Naphthas Category. American 

Group. VA, USA. 

m-xylene 

substances represented by the 10 CAS numbers under Test 

Test Substance: 

64741-98-6 

64742-48-9 

64742-49-0 

64742-83-2 Naphtha, petroleum, light steam-cracked 

68333-88-0 Aromatic hydrocarbons, C9-C17 

68476-45-9 Hydrocarbons, C5-10 aromatic concentration, 

ethylene-manufacture-by-product 

68478-10-4 Naphtha, petroleum, light steam-cracked, 

debezenized, C8-16-cycloalkadiene concentrate 

68516-20-1 Naphtha, petroleum, steam-cracked middle aromatic 

68527-23-1 Naphtha, petroleum, light steam-cracked aromatic 

68919-15-3 Hydrocarbons, C6-12, benzene-recovery 

production processes associated with ethylene manufacturing. 

product streams associated with the ethylene industry. 

found in the American Chemistry Council, Olefins Panel test plan 

Chemistry Council, Olefins Panel, HPV Implementation Task 

Page 2 of 3 
Water Solubility (Range) 

CAS No.: 64741-98-6; 64742-48-9; 64742-49-0; 64742-83-2; 68333-88-0; 68476-45-9; 68478-10-

4; 68516-20-1; 68527-23-1; 68919-15-3 

Robust Summary No.: OP E664 

Conclusion: The calculated water solubility for some representative 

constituents that are present in the category streams vary from 

21.5 to 832.7 mg/L @ 25°C. The measured water solubility of 

these same constituents vary from 41.4 to 573.1 mg/L @ 25°C. 

Although this does not define the actual water solubility of the 

category streams, it offers an indication of a range that might be 

expected to encompass the water solubility of these complex 

streams with variable compositions. Water solubilities outside 

these ranges may be possible for some category streams. 

Reliability: (2) Reliable with restrictions 

The results include calculated data based on chemical structure as 

modeled by EPIWIN and measured data for specific chemicals as 

cited in the EPIWIN database. The data represent a potential 

water solubility range for substances represented by the 10 CAS 

numbers under Test Substance. This robust summary has a 

reliability rating of 2 because the data are not for specific 

substances in the Low Benzene Naphthas Category, but rather for 

selected constituents. These selected constituents represent all 

substances defined by this category and as such, this robust 

summary represents a "key study" for water solubility range based 

on constituent data. 

Reference: EPIWIN. 1999. Estimation Program Interface for Windows, version 

3.04. Syracuse Research Corporation, Syracuse, NY, USA. 

(Water solubility values were calculated by the WSKOWWIN 

subroutine and measured data came from the database in the 

computer program.) 

Other (source): American Chemistry Council, Olefins Panel (Prepared 7/03) 

* Other TS is a selection option under the Test Substance pick list that is in the IUCLID entry field 

for Water Solubility. Selecting this option refers the reader to information in the test substance 

"freetext" field to which the CAS numbers can be added. 

Page 3 of 3