bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of N‐hexadecyl‐N, N,N‐trimethylammonium nitrate on the dehydrobromination reaction of 2‐phenylethyl derivatives
Authors: Wilk Kazimiera A. 
Published: January 2005

AbstractThe basis dehydrobromination of p‐substituted 2‐phenylethyl bromides promoted by hydroxide ion has been studied in micelles of N‐hexadecyl‐N,N,N‐trimethylammonium nitrate (CTANO3). The pseudophase ion exchange model can be adapted to explain the kinetic results at low hydroxide ion concentration, i.e., less than 0.075 M of NaOH. At high hydroxide ion concentration in solution the applied model does not describe the kinetic results unless the empirical variations are applied for the mol ratio of reactive ion to micellar head group (β) and the binding constant of the organic reagent to the micelle (Ks).
The rate coefficient for the reaction of O(3P) with CH3OOH at 297 K
Authors: Vaghjiani Ghanshyam L. , Ravishankara A. R. 
Published: January 2005

AbstractThe absolute second‐order rate coefficient for the reaction, O(3P) + CH3OOH → products, was measured to be 𝓀1 = (1.06 ± 0.26) × 10−14 cm3 molec−1 s−1 at 297 K, where the quoted error is 2σ including precision and estimated systematic errors. The possible presence of (CH3CH2)2O in our sample of CH3OOH leads to a large error in 𝓀1 which reflects the relatively large uncertainty indicated. O(3P) was generated in excess CH3OOH by photolyzing a small amount of O3 at 532 nm, where CH3OOH does not photolyze. The rate of removal of O(3P) in the experiments was monitored by resonance fluorescence detection. The increased reactivity of O(3P) with CH3OOH relative to H2O2 is interpreted as due to H abstraction from the CH3 group.
Time‐resolved mass spectrometric study of the reaction H + Trans‐2‐Butene
Authors: Herman Kazimiera , Forst Wendell 
Published: January 2005

AbstractThe title reaction was studied in a discharge flow system using mass flow and modulated molecular beam sampling with phase‐sensitive detection in order to obtain time‐resolved mass spectrometric analysis. At total conversion exceeding 30%, the major products are methane and ethane when initially hydrogen atoms are in excess; when butene is in excess, the major products are ethane and propylene. No hydrocarbons with more than 4 carbon atoms were detected in the products. The reaction is a complicated one since the simplest reaction scheme that successfully simulates the experimental results comprises 20 elementary reactions. The simulation, coupled with sensitivity analysis, shows that with hydrogen atoms in excess, significant amounts of propylene formed in the initial decomposition of the butyl radical react further with hydrogen atoms to form methane and ethane. When butene is in excess, approximately [C3H6] ≈ [CH4] + ½[C2H6] which means that this propylene does not react further and almost all methyl radicals end up as CH4 or C2H6. At small conversion, simulation shows that the major product by far is propylene regardless of the [H]/[butene] ratio. The absence of higher hydrocarbons in the products is at variance with earlier results of Rabinovitch and coworkers; however the present work leads to a comparable value for the average rate constant 𝓀a = ωD/S where D and S is the amount of products arising from the decomposition and stabilization, respectively, of the butyl radical and ω is the collision frequency.
Kinetics of alkaline hydrolysis of organic esters and amides in neutrally‐buffered solution
Authors: Robinson Bruce A. , Tester Jefferson W. 
Published: January 2005

AbstractReaction rate constants for the hydrolysis of organic esters and amides were determined at temperatures of 100–240°C in aqueous solutions buffered at pH values between 5.5 and 7.3. Experiments are modeled assuming alkaline hydrolysis with a thermodynamic solution model included to account for the temperature dependence of hydroxide ion concentration. In most cases, the ester hydrolysis second order rate constants agree well with published values from experiments in strongly basic solutions at pH values from 11 to 14 and temperatures from 25–80°C, despite the large extrapolations required to compare the data sets. The amide hydrolysis rate constants are about one order of magnitude higher than the extrapolated results from other investigators, but the reaction rate increased proportionally with hydroxide ion concentration, suggesting that an alkaline hydrolysis mechanism is also appropriate. These data establish the validity of the alkaline hydrolysis mechanism and can be used to predict hydrolysis reaction rates in neutrally‐buffered solutions such as many groundwater and geothermal fluids.
A shock tube study of the CH2O + NO2 reaction at high temperatures
Authors: Lin Chin‐Yu , Wang Hung‐Tai , Lin M. C. , Melius C. F. 
Published: January 2005

AbstractThe reaction of CH2O with NO2 has been studied with a shock tube equipped with two stabilized ew CO lasers. The production of CO, NO, and H2O has been monitored with the CO lasers in the temperature range of 1140–1650 K using three different Ar‐diluted CH2O‐NO2 mixtures. Kinetic modeling and sensitivity analysis of the observed CO, NO, and H2O production profiles over the entire range of reaction conditions employed indicate that the bimolecular metathetical reaction, NO2 + CH2O → HONO + CHO (1) affects most strongly the yields of these products. Combination of the kinetically modeled values of 𝓀1 with those obtained recently from a low temperature pyrolytic study, ref. [8], leads to

for the broad temperature range of 300–2000 K.
Background reactivity in smog chambers
Authors: Killus James P. , Whitten Gary Z. 
Published: January 2005

AbstractData from several smog chamber reaction vessels have been analyzed in an attempt to elucidate the chemical species which are responsible for chamber specific background phenomena, and the nature of the processes which determine the heterogeneous interactions of those species. There is good evidence for the emission of a compound which yields both NOx, and free radicals (probably HONO) and emissions of reactive organics (e.g. HCHO) may also be deduced. Total integrated chamber emission of these compounds may be as high as 20 to 60 ppb during a typical smog chamber experiment. In addition to the direct emission of these contaminants, the surface reaction of NO2 and H2O to HONO is examined. In some cases this reaction may have as great an effect on a smog chamber experiment as the emission of trace contaminants. Overall chamber perturbations to gas phase chemistry have been estimated for several experiments and were found to be less than 20 percent in the majority of cases, although higher perturbations were found in experiments involving compounds of low reactivity such as butane.
Kinetics and mechanism for the oxidation of 1,1,1‐trichloroethane
Authors: Nelson Linda , Shanahan Imelda , Sidebottom Howard W. , Treacy Jack , Nielsen Ole J. 
Published: January 2005

AbstractThe reaction mechanisms for oxidation of CH3CCl2 and CCl3CH2 radicals, formed in the atmospheric degradation of CH3CCl3 have been elucidated. The primary oxidation products from these radicals are CH3CClO and CCl3CHO, respectively. Absolute rate constants for the reaction of hydroxyl radicals with CH3CCl3 have been measured in 1 atm of Argon at 359, 376, and 402 K using pulse radiolysis combined with UV kinetic spectroscopy giving 𝓀(OH + CH3CCl3) = (5.4 ± 3) 10−12 exp(−3570 ± 890/RT) cm3 molecule−1 s−1. A value of this rate constant of 1.3 × 10−14 cm3 molecule−1 s−1 at 298 K was calculated using this Arrhenius expression. A relative rate technique was utilized to provide rate data for the OH + CH3 CCl3 reaction as well as the reaction of OH with the primary oxidation products. Values of the relative rate constants at 298 K are: 𝓀(OH + CH3CCl3) = (1.09 ± 0.35) × 10−14, 𝓀(OH + CH3CClO) = (0.91 ± 0.32) × 10−14, 𝓀(OH + CCl3CHO) = (178 ± 31) × 10−14, 𝓀(OH + CCl2O) < 0.1 × 10−14; all in units of cm3 molecule−1 s−1. The effect of chlorine substitution on the reactivity of organic compounds towards OH radicals is discussed.
Reaction rate constant of SO3 + CH3OH in the gas phase
Authors: Shen Guanlin , Suto Masako , Lee L. C. 
Published: January 2005

AbstractThe reaction rates of SO3 with CH3OH in He were measured at total pressures of 0.7–1.6 torr in flow tubes. The concentration of SO3 was monitored by the SO2* fluorescence from excitation of SO3 at 147 nm. The reaction rate constant of SO3 + CH3OH in the gas phase is determined to be (1.17 ± 0.16) × 10−13 cm3 molec−1 s−1 at room temperature.
FTIR study of the Cl‐atom initiated oxidation of methylglyoxal
Authors: Green M. , Yarwood G. , Niki H. 
Published: January 2005

AbstractThe kinetics and mechanism of Cl‐atom initiated reactions of CH3C(O)CHO were studied using the FTIR detection method in the photolysis (λ < 300 nm) of Cl2CH3C(O)CHO mixtures in 700 torr of N2O2 diluent at 298 ± 2 K. The observed product distribution over the O2 pressure range from 0–700 torr, combined with relative rate measurements, provided evidence that: (1) the primary step is Cl + CH3C(O)CHO → HCl + CH3C(O)CO with a rate constant of (4.8 ± 1.1) × 10−11 cm3 molecule−1 s−1; and (2) the predominant fate of the primary radical CH3C(O)CO under atmospheric conditions is unimolecular dissociation to CH3C(O) radicals and CO, rather than O2‐addition to yield the corresponding carbonylperoxy radical CH3C(O)C(O)OO.
Rate constants for the gas‐phase reactions of O3 with a series of monoterpenes and related compounds at 296 ± 2 K
Authors: Atkinson Roger , Hasegawa David , Aschmann Sara M. 
Published: January 2005

AbstractRate constants for the gas‐phase reactions of O3 with a series of monoterpenes and related compounds have been determined at 296 ± 2 K and 740 torr total pressure of air or O2 using a combination of absolute and relative rate techniques. Good agreement between the absolute and relative rate data was observed, and the rate constants obtained (in units of 10−17 cm3 molecule−1 s−1) were: α‐pinene, 8.7; β‐pinene, 1.5; Δ3‐carene, 3.8; 2‐carene, 24; sabinene, 8.8; d‐limonene, 21; γ‐terpinene, 14; terpinolene, 140; α‐phellandrene, 190; α‐terpinene, 870; myrcene, 49; trans‐ocimene, 56; p‐cymene, <0.005; and 1,8‐cineole, <0.015. While these rate constants for α‐ and β‐pinene and sabinene are in good agreement with recent absolute and relative rate determinations, those for the other monoterpenes are generally lower than the literature data by factors of ca. 2–10. The measured rate constants for the monoterpenes are reasonably consistent with predictions based upon the number and positions of the substituent groups around the 〉CC〈 bond(s).
Reactions of naphthalene in N2O5NO3NO2 air mixtures
Authors: Atkinson Roger , Tuazon Ernesto C. , Arey Janet 
Published: January 2005

AbstractThe reactions of naphthalene in N2O5NO3NO2N2O2 reactant mixtures have been investigated over the temperature range 272–297 K at ca. 745 torr total pressure and at 272 K and ca. 65 torr total pressure using long pathlength Fourier transform infrared absorption spectroscopy. 2,3‐Dimethyl‐2‐butene was added to the reactant mixtures at 272 K to rapidly scavenge the NO3 radicals both initially present in the added N2O5 and formed from the thermal decomposition of N2O5 during the reactions. The data obtained in the presence and absence of added 2,3‐dimethyl‐2‐butene showed that napthalene undergoes initial reaction with the NO3 radical to form an NO3‐naphthalene adduct, which either rapidly decomposes back to the reactants (at a rate of ca. 5 × 105 s−1 at 298 K) or reacts exclusively with NO2 to form products. When NO3 radicals, N2O5 and NO2 are in equilibrium, this overall process is kinetically equivalent to reaction of naphthalene with N2O5, and previous kinetic and product studies have indeed assumed the reactions of naphthalene and alkyl‐substituted naphthalenes in N2O5NO3NO2air mixtures to be with N2O5, and not with NO3 radicals.
Kinetics of electron transfer reactions of manganese (III) complexes of trans‐cyclohexane‐1,2‐diamine,‐NNN′N′‐tetraacetic acid and 2,2′‐bipyridyl with ascorbic acid in aqueous acid media
Authors: Gangopadhyay Sumana , Saha Swapan K. , Ali Mahammad , Banerjee Pradyot 
Published: January 2005

AbstractThe kinetics of the reactions of manganese(III) complexes of trans‐cyclohexane‐1,2‐diamine‐NNN′N′‐tetraacetic acid (H4cydta) and 2,2′‐bipyridyl (bpy) have been investigated in the acid ranges [H+] = 1.00 ×10−5 − 3.16 × 10−3 M and [H+] = 0.10 − 1.00 M, respectively, at different temperatures and at a constant ionic strength. Both the molecular and mono‐anionic forms of ascorbic acid have been found to be reactive in the experimental acid ranges. The monoanionic species has been found to be more reactive than the molecular form. Attempts have been made to correlate the kinetic results in terms of the Marcus relationship for outer‐sphere electron transfer reaction. Differences between the calculated rates (k0.8) and experimental rates (k) by approximately four and seven orders of magnitude (k0.8≪ k) suggest an innersphere pathway for the reaction of Mn(cydta)(H2O)−. Inner‐sphere reaction is also believed to be operative for the other reaction. The activation parameters have been evaluated and compared with other reported systems.
Kinetics of CN reactions with N2O and CO2
Authors: Wang N. S. , Yang D. L. , Lin M. C. , Melius C. F. 
Published: January 2005

AbstractThe rate constants for the reaction of CN with N2O and CO2 have been measured by the laser dissociation/laser‐induced fluorescence (two‐laser pump‐probe) technique at temperatures between 300 and 740 K. The rate of CN + N2O was measurable above 500 K, with a least‐squares averaged rate constant, k = 10−11.8±0.4 exp(−3560 ± 181/T) cm3/s. The rate of CN + CO2, however, was not measurable even at the highest temperature reached in the present work, 743 K, with [CO2] ⩽ 1.9 × 1018 molecules/cm3.In order to rationalize the observed kinetics, quantum mechanical calculations based on the BAC‐MP4 method were performed. The results of these calculations reveal that the CN + N2O reaction takes place via a stable adduct NCNNO with a small barrier of 1.1 kcal/mol. The adduct, which is more stable than the reactants by 13 kcal/mol, decomposes into the NCN + NO products with an activation energy of 20.0 kcal/mol. This latter process is thus the rate‐controlling step in the CN + N2O reaction. The CN + CO2 reaction, on the other hand, occurs with a large barrier of 27.4 kcal/mol, producing an unstable adduct NCOCO which fragments into NCO + CO with a small barrier of 4.5 kcal/mol. The large overall activation energy for this process explains the negligibly low reactivity of the CN radical toward CO2 below 1000 K.Least‐squares analyses of the computed rate constants for these two CN reactions, which fit well with experimental data, give rise to

for the temperature range 300–3000 K.
Kinetic studies of the reactions of IO, BrO, and ClO with dimethylsulfide
Authors: Barnes I. , Bastian V. , Becker K. H. , Overath R. D. 
Published: January 2005

AbstractThe kinetics of the reactions of IO, BrO, and ClO with DMS have been investigated at 298 K and total pressures of 0.5–6.8 mbar He using the discharge flow‐mass spectrometry technique to monitor the halogen oxide radicals. Rate coefficients of (8.8 ± 2.1) × 10−15, (2.7 − 0.5) × 10−13 and (9.5 ± 2.0) × 10−15 cm3 molecule−1 s−1 have been obtained for the reactions of IO, BrO, and ClO with DMS, respectively. The result for IO with DMS is in good agreement with two other recent studies on this reaction but is nearly three orders of magnitude slower than two earlier studies, one of which was from this laboratory. The earlier studies are now thought to be in error because of heterogeneous and secondary chemistry occurring in the systems investigated. The rate coefficient for BrO with DMS is in excellent agreement with a previously reported preliminary value from this laboratory. However, the rate coefficient for ClO with DMS is a factor of 4 lower than our previously determined value. The new data are considered more reliable in view of the much improved experimental technique in the present study. DMSO was detected as a product in all of these reactions. A semi‐quantitative determination of the DMSO yield was only possible in the case of the reaction of IO with DMS where a yield of 84 ± 40% was found.
Kinetics of the reaction between H atoms and allyl radicals
Authors: Hanning‐Lee Mark A. , Pilling Michael J. 
Published: January 2005

AbstractThe reaction between H and C3H5 has been studied at 291 K. Exciplex laser flash photolysis at 193.3 nm of hexa‐1,5‐diene‐He mixtures generated both H and C3H5 ([H] ≪ [C3H5]), which were detected in time‐resolved mode by resonance fluorescence and absorption spectroscopy, respectively. Rate coefficients are presented at four pressures in the range 98 ⩽ P/torr ⩽ 400; no clear pressure‐dependence is found in this range of pressures and the mean rate coefficient is (2.8 ± 1.0) × 10−10 cm3 molecule−1 s−1. Calculations based on the Troe factorization method confirm that this reaction is near its high‐pressure limit under the experimental conditions.
Kinetics and mechanism of decarboxylation of aspartic acid with ninhydrin
Authors: Zhan Zaheer , Gupta Dileep , Khan A. Aziz 
Published: January 2005

AbstractThe kinetic study of the decarboxylation of aspartic acid has been carried out at various [ninhydrin], [H+] and at different temperature ranging from 60–95°C. The reaction follows an irreversible first‐order reaction path under pseudo first‐order kinetic conditions. The variation of pseudo first‐order rate constant (kobs) with ninhydrin concentration was found to be in agreement with equation 1/kobs = B1 + B2/[Ninhydrin]. One mol of carbondioxide evolved from decarboxylation of α‐COOH and second mol of carbondioxide comes from the decarboxylation of β‐keto acid which is an intermediate and formed during the course of ninhydrin and aspartic acid reaction. On the basis of the observed data, a possible mechanism has been proposed.
Rate constants for the gas‐phase reactions of O3 with a series of alkenes at 296 ± 2 K
Authors: Greene Chipper R. , Atkinson Roger 
Published: January 2005

AbstractThe kinetics of the gas‐phase reactions of O3 with a series of alkenes have been investigated at atmospheric pressure (ca. 740 torr) of air and 296 ± 2 K, using a relative rate method in the presence of sufficient n‐octane to scavenge any OH radicals generated in these reactions. Relative to k(O3 + propene) = 1.00, the rate constants obtained were: 1‐butene, 0.975 ± 0.030; 2‐methylpropene, 1.14 ± 0.04; 2‐methyl‐1,3‐butadiene (isoprene), 1.21 ± 0.02; 1,4‐cyclohexadiene, 4.75 ± 0.23; cyclohexene, 7.38 ± 0.48; cis‐2‐butene, 12.8 ± 0.8; trans‐2‐butene, 21.5 ± 1.5; 2‐methyl‐2‐butene, 42.1 ± 2.8; cyclopentene, 64.9 ± 4.3; and 2,3‐dimethyl‐2‐butene, 123 ± 11. These relative rate constants have been placed on an absolute basis using a rate constant for the reaction of O3 with propene of 1.01 × 10−17 cm3 molecule−1 s−1 at 296 K derived from an analysis of the available literature data. The resulting rate constants then lead to a self‐consistent set of room temperature data for the reactions of O3 with these alkenes. © John Wiley & Sons, Inc.
Kinetics of the reaction of H(2S) with HBr
Authors: Talukdar Ranajit K. , Warren Rachel F. , Vaghijiani Ghanshyam L. , Ravishankara A. R. 
Published: January 2005

AbstractThe rate constants for the reaction H + HBr → H2 + Br were measured between 217 and 383 K using pulsed laser photolysis of HBr and cw resonance fluorescence detection of H(2S). The temporal profiles of the product Br atoms were also monitored to obtain the rate constant at 298 K. The yield of Br from the reaction was determined to be unity. The rate coefficient as a function of temperature is given by the Arrhenius expression, k
1 = (2.96 ± 0.44) × 10−11 exp(−(460 ± 40)/T) cm3 molecule−1 s−1. The quoted errors are at the 95% confidence level and include estimated systematic errors. Our results are compared with those from previous direct measurements. © John Wiley & Sons, Inc.
UV absorption spectra, kinetics, and mechanisms of the self reaction of CF3O2 radicals in the gas phase at 295 K
Authors: Nielsen Ole J. , Ellermann Thomas , Sehested Jens , Bartkiewicz Elzbieta , Wallington Timothy J. , Hurley Michael D. 
Published: January 2005

AbstractThe ultraviolet absorption spectrum and the self reaction kinetics of CF3O2 radicals have been studied in the gas phase at 298 K using the pulse radiolysis technique. Long pathlength Fourier transform infrared (FTIR) spectroscopy was used to identify and quantify reaction products. Absorption cross sections were quantified over the wavelength range 215–270 nm. The measured cross section at 230 nm was;

Errors represent statistical (2σ) together with our estimate of potential systematic errors. The absorption cross section data were then used to derive the observed self reaction rate constant for reaction (1), defined as −d[CF3O2]/dt = 2k obs[CF3O2]2

equation image

klobs = (3.6 ± 0.9) × 10−12 cm3 molecule−1 s−1. The only carbon containing product observed by FTIR spectroscopy was CF3OOOCF3. Consideration of the loss of CF3O2 radicals to form the trioxide CF3OOOCF3 allows derivation of the true bimolecular rate constant for reaction (1); k1 = (1.8 ± 0.5) × 10−12 cm3 molecule−1 s−1. These results are discussed with respect to previous studies of the absorption spectra of peroxy radicals, the kinetics, and mechanisms of their self reaction. © John Wiley & Sons, Inc.
Kinetics of the N‐chlorination of 2‐aminobutyric, 3‐aminobutyric, 3‐aminoisobutyric and 4‐aminobutyric acids in aqueous solution
Authors: Antelo J. M. , Arce F. , Pérez‐moure J. C. 
Published: January 2005

AbstractWe studied the kinetics of the N‐chlorination of 2‐aminobutyric, 3‐aminoisobutyric, and 4‐aminobutyric acids by sodium hypoclorite in strongly alkaline aqueous solution. As in the case of other amines, the rate of formation of the four N‐chloroamino acids was proportional to the concentrations of hypochlorite and amino acid, and inversely proportional to the concentration of hydroxyl ions. A reaction mechanism compatible with these results is proposed and discussed. © John Wiley & Sons, Inc.
Kinetics and mechanism of dimerization of arylmercurials
Authors: Wang Yulan 
Published: January 2005

AbstractThe kinetics of dimerization of arylmercurials XC6H4HgCl (X  H, p‐CH3, m‐CH3, p‐Cl, m‐OCH3, m‐CO2C2H5, and o‐OCH3) in the presence of [ClRh(CO)2]2 was studied in hexamethylphosphoramide (HMPA). The experimental rate law obtained is −d[ArHgCl]/dt=k[ArHgCl]2. The kinetic parameters of these reactions have been reported, and the variation, therein, has been explained on the basis of steric effect of substituents. The apparent activation energy E is linearly proportional to pre‐exponential factor lnA. A most plausible mechanism has been proposed on the basis of experimental results. © 1993 John Wiley & Sons, Inc.
Kinetics of base hydrolysis of tris‐(1,10‐phenanthroline)iron(II) and of solvolysis of cis‐dichlorobis(1,2‐ethanediamine)cobalt(III) in water + diol mixtures
Authors: Alshehri S. , Burgess J. 
Published: January 2005

AbstractRate constants for base hydrolysis of the tris‐(1,10‐phenanthroline)iron(II) cation and for solvolysis of the cis‐dichlorobis(1,2‐ethanediamine)cobalt(III) cation have been measured in binary aqueous mixtures containing 1,2‐ethanediol, 1,2‐ or 1,4‐butanediol, 1,2‐ or 1,6‐hexanediol, 1‐propanol, or t‐butyl alcohol, at 298.2 K. Kinetics of base hydrolysis of the cobalt(III) complex have also been monitored in methanol‐water and ethanol‐water mixtures, again at 298.2 K. The observed reactivity trends are discussed in terms of the hydrophilic and hydrophobic properties of the respective diols. The dominant factor determining reactivity is hydration of the attacking hydroxide or leaving chloride, as is evidenced by the close correspondence between rate constants and transfer chemical potentials for these anions. The role of hydration has also been probed through the determination of activation volumes for these two reactions in 60% 1,4‐butanediol. © 1993 John Wiley & Sons, Inc.