bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetic study of hydroxylamine‐bromate ion reaction in acid sulfate solution—a competitive consecutive reaction
Authors: Jonnalagadda Sreekantha B. 
Published: January 2005

AbstractA kinetic study of oxidation of hydroxylamine by bromate ion in acid sulfate solution using spectrophotometric and potentiometric methods is reported. Oxidation of hydroxylamine to nitrate is quantitative and followed competitive, consecutive, and auto catalytics steps characterized by induction periods. In the slow rate limiting step, hydroxylamine on reaction with HOBr (k) forms an intermediate I, which further reacts fast with second molecule of HOBr (k) giving nitrite. Nitrite reacts with HOBr (k) yielding the final product nitrate. Nitric acts as an autocatalyst also and its initial addition decreased the induction periods. In excess of hydrogen ion concentration all the reaction steps follow second‐order kinetics. All the second‐order rate constants are reported and the reaction mechanism is proposed.
Kinetics of the reaction Cl + NO2 + M
Authors: Leu Ming‐Taun 
Published: January 2005

AbstractThe termolecular rate constant for the reaction Cl + NO2 + M has been measured over the temperature range 264 to 417 K and at pressure 1 to 7 torr in a discharge flow system using atomic chlorine resonance fluorescence at 140 nm to monitor the decay of Cl in an excess of NO2. The results are\documentclass{article}\pagestyle{empty}\begin{document}$k_1^{{\rm He}} = 9.4{\rm } \times {\rm }10^{ - 31} \left({\frac{T}{{300}}} \right)^{ - 2.0 \pm 0.05} {\rm cm}^6 {\rm s}^{ - {\rm 1}}$\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$k_1^{{\rm N}2} = (14.8{\rm } \pm {\rm }1.4){\rm } \times {\rm 10}^{ - 31} {\rm cm}^6 {\rm s}^{ - 1}$\end{document} at 296 K where error limits represent one standard deviation. The systematic error of k1 measurements is estimated to be about 15%. Using a static photolysis system coupled with the FTIR spectrophotometer the branching ratio for the formation of the two possible isomers was found to be ClONO(⩾75%) and CINO2(⩽25%) in good agreement with previous measurements.
Optimizing the use of the Kezdy–Mangelsdorf–Swinbourne method for analysis of data following a exp(–kt) + Z
Authors: McKinnon G. H. , Backhouse C. J. , Kalantar A. H. 
Published: January 2005

AbstractThe use of the KMS method for the evaluation of the exponent by the experimentalist requires that a lag or retardation be chosen. The best choice of lag is discussed quantitatively. Its dependence upon the decade range of the data, the relative magnitude of the background, the level and character of the noise, the number and distribution of the data, and the weighted least‐squares method of analysis are all detailed. A table of lags and error factors is given, for various ranges, backgrounds, and kinds of noise. Bias in the extracted rate (k), due to noise and treatment of the data, is also discussed.
Kinetics of nonisothermal calcination of ZnCO3 in air
Authors: Gadalla Ahmed M. 
Published: January 2005

AbstractThermal curves obtained simultaneously at constant heating rates were used to study calcination of ZnCO3 in air. Carroll and Manche's technique, Reich's equation, and Kissinger's method gave an average value for the activation energy of 23 kcal/mol. On the other hand, Coats and Redfern's technique showed the activation energy and preexponential factor to vary over wide ranges. They increase to a maximum and decrease again on increasing the temperature. Their values decrease as the heating rate was increased. One‐dimensional diffusion mechanism, obeying parabolic law, may control the entire calcination process.
Reactivity of allylic hydrogen in cyclohexadiene towards OH radicals
Authors: Ohta Tomohiro 
Published: January 2005

AbstractThe yield of benzene in the reaction of 1,4‐ and 1,3‐cyclohexadiene with OH radicals in the presence of oxygen was determined using H2O2 and CH3ONO as OH radical sources. Both in the H2O2 and the CH3ONO systems, the yield of benzene from 1,4‐cyclohexadiene was 15.3% and the yield from 1,3‐cyclohexadiene was 8.9%. On the basis of the obtained yields, the rate constant for allylic hydrogen abstraction per CH in cyclohexadiene was determined to be 3.8 × 10−12 cm3 molecule−1 s−1. The branching ratio of the hydrogen abstraction to overall reaction for 1‐butene and 1‐pentene was estimated to be (25–14)% by applying the obtained rate constants. The result was in good agreement with the branching ratio determined directly by use of the discharge flow photoionization mass spectrometer by Biermann, Harris, and Pitts [4].
A shock tube study of the reaction of the hydroxyl radical with propane
Authors: Bott J. F. , Cohen N. 
Published: January 2005

AbstractThe rate coefficient for the reaction of the hydroxyl radical, OH, with propane has been measured at 1220 K in shock tube experiments, and a value of (1.58 ± 0.24) × 1013 cm3/mol s was obtained. This measured value is compared with previous experimental results and a transition‐state theory calculation.
Kinetics of OH reactions with aliphatic thiols
Authors: Wine P. H. , Thompson R. J. , Semmes D. H. 
Published: January 2005

AbstractThe kinetics of OH reactions with 1–4 carbon aliphatic thiols have been investigated over the temperature range 252–430 K. OH radicals were produced by flash photolysis of water vapor at λ > 165 nm and detected by time‐resolved resonance fluorescence spectroscopy. All thiols investigated react with OH at nearly the same rate; k(298 K) = 3.2–4.6 × 10−11 cm3 molecule−1 s−1, ‐Eact = 0.6–1.0 kcal/mol, A = 0.6–1.2 × 10−11 cm3 molecule−1 s−1. CH3SH and CH3SD react with OH at identical rates over the entire temperature range investigated. We conclude that the dominant reaction pathway is addition to the sulfur atom.
Principal component analysis of kinetic models
Authors: Vajda S. , Valko P. , Turányi T. 
Published: January 2005

AbstractAn eigenvalue–eigenvector analysis is used to extract meaningful kinetic information from linear sensitivity coefficients computed for several species of a reacting system at several time points. The main advantage of this method lies in its ability to reveal those parts of the mechanism which consist of strongly interacting reactions, and to indicate their importance within the mechanism. Results can be used to solve three general kinetic problems. Firstly, an objective condition for constructing a minimal reaction set is presented. Secondly, the uncovered dependencies among the parameters are shown to confirm or deny validity of quasi‐steady‐state assumptions under the considered experimental conditions. Thirdly, taking into account only sensitivities of observed species, the analysis is used to yield error estimates on unknown parameters determined from the experimental observations, and to suggest the parameters that should be kept fixed in the estimation procedure. To illustrate we chose the well‐known hydrogen–bromine reaction and the kinetics of formaldehyde oxidation in the presence of CO.
Homolytic substitution in trialkyltin iodides by photochemically generated iodine atoms. I. Kinetics
Authors: De Ryck P. H. , Verdonck L. , Van Der Kelen G. P. 
Published: January 2005

AbstractThe kinetics of the homolytic substitution of several trialkyltin iodides by iodine atoms are presented. Rate constants have been determined at three different temperatures and the following activation parameters calculated: A, Ea, and ΔS°≠. The observation that the activation energy, ΔG≠, is related to the driving force of the ion‐pair formation, leads to the conclusion that the charge‐transfer model is a valid approach for substitution in the reaction between R3SnI compounds and iodine atoms.
Relative rate constants of the gas‐phase decomposition reactions of the s‐butoxy radical
Authors: Drew Roger M. , Alistair Kerr J. , Olive Jonathan 
Published: January 2005

Abstracts‐Butoxy radicals have been generated by reacting fluorine with s‐butanol:

Over the temperature range 398.6 to 493.3 K the s‐butoxy radical decomposes by two different pathways to yield acetaldehyde and propionaldehyde, acetaldehyde being the major product:
equation image
The ratio k1/k2 was found to be temperature dependent. An Arrhenius plot of the data (398.6 to 493.3 K) yields the relative Arrhenius parameters, E1 ‐ E2 = −11.2 ± 0.8 kJ mol−1 and (A1/A2) = 0.59 ± 0.14. The ratio of rate constants k1/k2 was shown to be independent of total pressure (80–600 torr) and of the pressure of s‐butanol (2–13 torr). The kinetic results for these s‐butoxy decomposition reactions are discussed in relation to the literature data and in terms of the thermochemistry of the reactions.
Rate constant for the reaction Cl + HO2NO2 → products
Authors: Simonaitis R. , Leu M. T. 
Published: January 2005

AbstractThe total rate constant for the reaction of Cl atoms with HO2NO2 was found to be less than 1.0 × 10−13 cm3 s−1 at 296 K by the discharge flow/resonance fluorescence technique. The reaction was also studied by the discharge flow/mass spectrometric technique. k1a + k1b was measured to be (3.4 ± 1.4) × 10−14 cm3 s−1 at 296 K. The reaction is too slow to be of any importance in stratospheric chemistry.
Kinetics and mechanism of the decomposition of N,N‐dihalopeptides
Authors: Stanbro William D. , Lenkevich Michael J. 
Published: January 2005

AbstractThe tripeptide alanylalanylalanine reacts with either HOCl or HOBr to form a N,N‐dihalopeptide. These compounds decompose to the N‐halo‐N′‐(α‐iminoketo)peptides plus halide ion. The rate constants for these reactions in 0.4‐M NaCl were determined to be

where the activation energies are in cal/mol. The N‐halo‐N′‐(α‐iminoketo)‐peptides slowly decompose either by a two‐step hydrolysis reaction to form ammonia, halide ion, and an N‐(α‐acylketo)peptide, or by direct decomposition to a nitrile, an isocyanopeptide, and a halide ion.
The steady‐state oxidation of CO on rhodium(100)
Authors: Daniel W. M. , White J. M. 
Published: January 2005

AbstractIn this article, we present low‐pressure steady‐state results for carbon monoxide oxidation over Rh(100). The results are comparable to those found for other Group VIII transition metals. For a fixed oxygen pressure, the reaction rate is first order in CO pressure until a critical pressure is reached, above which the reaction rate sharply diminishes and the order becomes negative in CO pressure. Coverages of carbon monoxide under steady‐state working conditions have been measured.
Intramolecular catalysis and the rate‐determining step in the alkaline hydrolysis of ethyl salicylate
Authors: Khan M. Niyaz , Gambo S. K. 
Published: January 2005

AbstractThe alkaline hydrolysis of ethyl salicylate has been studied at 35°C within the [ŌH] range of 0.001–2.00 M. The observed hydroxide ion concentration dependence of rate has been explained by proposing the occurrence of two parallel kinetic steps shown as in the rate law: rate = k1[H2O] [ES] + k2[ŌH] [ES] where ES− represents ionized ethyl salicylate. The value of k1, is ca. 106 times larger than the expected value of rate constant for uncatalyzed aqueous cleavage of ethyl‐p‐hydroxybenzoate. This rate advantage is attributed to intramolecular general base catalysis. The analysis of observed activation parameters indicates that ca. 106 times rate enhancement is entirely due to favorable entropy change. The Brønsted‐type plots show an extremely low sensitivity of rate constants k1 and k2 with respective Brønsted coefficient of β = −0.03 ± 0.01 and β = −0.01 ± 0.05, on the basicity of leaving groups of salicylate esters (alkoxide and phenoxide ions). The low values of these Brønsted coefficients indicate essentially little or an insignificant amount of bond cleavage between carbonyl carbon and leaving group in the rate‐determining step in both the k1 and k2 steps. The rate constants obtained at different ethanol concentration follow Grunwald‐Winstein mY equation with m = 0.14 ± 0.01.
Complex dynamical behavior in a new chemical oscillator: The chlorite–thiourea reaction in a CSTR
Authors: Alamgir Mohamed , Epstein Irving R. 
Published: January 2005

AbstractThe reaction between chlorite ion and thiourea has been studied both in a closed (batch) system and in a flow reactor (CSTR). The principal stoichiometry is given by

In batch, the reaction displays an induction period, whose length is proportional to [CS(NH2)2]/[ClO] [H+], followed by the rapid buildup and disappearance of a ClO2 intermediate. At [ClO]/[CS(NH2)2] ratios between 2.5 and 3.5, a second peak in the ClO2 absorbance is observed. In the CSTR, this iodine‐free system displays simple and complex periodic oscillation, bistability, aperiodic oscillation, and birhythmicity.
Reactions of alkoxy radicals with O2. III. i‐C4H9O radicals
Authors: Zabarnick Steven , Heicklen Julian 
Published: January 2005

Abstracti‐C4H9ONO was photolyzed with 366‐nm radiation at −8, 23, 55, 88, and 120°C in a static system in the presence of NO, O2, and N2. The quantum yield of i‐C3H7CHO, Φ{i‐C3H7CHO}, was measured as a function of reaction of reaction conditions. The primary photochemical act is
equation image
and it proceeds with a quantum yield ϕ1 = 0.24 ± 0.02 independent of temperature. The i‐C4H9O radicals can react with NO by two routes
equation image
The i‐C4H9O radical can decompose via
equation image
or react with O2 via
equation image
Values of k4/k2 ≃ k4b/k2 were determined to be (2.8 ± 0.6) × 1014, (1.7 ± 0.2) × 1015, and (3.5 ± 1.3) × 1015 molec/cm3 at 23 55, and 88°C, respectively, at 150‐torr total pressure of N2. Values of k6/k2 were determined from −8 to 120°C. They fit the Arrhenius expression:

For k2 ≃ 4.4 × 1011 cm3/s, k6 becomes (3.2 ± 2.0) × 10−13 exp{−(836 ± 159)/T} cm3/s. The reaction scheme also provides k4b/k6 = 3.59 × 1018 and 5.17 × 1018 molec/cm3 at 55 and 88°C, respectively, and k8b/k8 = 0.66 ± 0.12 independent of temperature, where
equation image
An FTIR spectroscopic study of the reactions Br + CH3CHO → HBr + CH3CO and CH3C(O)OO + NO2 ⇌ CH3C(O)OONO2 (PAN)
Authors: Niki H. , Maker P. D. , Savage C. M. , Breitenbach L. P. 
Published: January 2005

AbstractBased on an FTIR‐product study of the photolysis of mixtures containing Br2CH3CHO and Br2CH3CHOHCHO in 700 torr of N2, the rate constant for the reaction Br + CH3CHO → HBr + CH3CO was determined to be 3.7 × 10−12 cm3 molecule−1 s−1. In addition, the selective photochemical generation of Br at λ > 400 nm in mixtures containing Br2CH3CHO14NO2 (or 15NO2)O2 was shown to serve as a quantitative preparation method for the corresponding nitrogen‐isotope labeled CH3C(O)OONO2 (PAN). From the dark‐decay rates of 15N‐labeled PAN in large excess 14NO2, the rate constant for the unimolecular reaction CH3C(O)OO15NO2 → CH3C(O)OO + 15NO2 was measured to be 3.3 (±0.2) × 10−4 s−1 at 297 ± 0.5 K.
Oxidation of naphthalene and phenanthrene by pyridinium fluorochromate (PFC)—a kinetic and mechanistic study
Authors: Bhattacharjee Bharati , Bhattacharjee Manabendra N. , Bhattacharjee Mitra , Bhattacharjee Apurba K. 
Published: January 2005

AbstractThe kinetics of the oxidation of naphthalene and phenanthrene by pyridinium fluorochromate, C5H5NHCrO3F, PFC, has been studied. The main product of the oxidation is the corresponding quinone. While each oxidation, studied in aqueous acetic acid (80–95%, v/v) medium, is first order with respect to the oxidant, the rate is almost independent of the substrate concentration. The reactions are catalyzed by acid, the acid‐catalyzed reactions being very fast, which precluded determination of their order in acid medium. The kinetic isotope effect, kH/kD is 5.50 at 303 K for naphthalene. The reaction does not induce polymerization of acrylonitrile. The effects of temperature and solvent compositions were studied and activation parameters evaluated. Probable mechanisms are discussed.
Spectra and reactions of acetyl and acetylperoxy radicals
Authors: Basco Norman , Parmar Sucha S. 
Published: January 2005

AbstractThe ultraviolet absorption spectra of the acetyl and acetylperoxy radicals have been characterized in the range 195–280 nm. The acetyl radical was generated by the flash photolysis of Cl2 in the presence of CH3CHO and was converted to the acetylperoxy radical in the presence of excess O2. The extinction coefficient of the acetylperoxy radical was measured to be 2300 L/mol cm at the maximum at 207 nm and the rate constant for the reaction

was evaluated to be k5 = (4.8 ± 0.8) × 109 L/mol s.
Relative rates of nucleophilic reactions of benzyl carbocation formed in photolysis of benzyl chloride and benzyl acetate in aqueous solution
Authors: Jaarinen Soili , Niiranen Jukka , Koskikallio Jouko 
Published: January 2005

AbstractBenzyl chloride and benzyl acetate were photolyzed in 30% methanol–water mixtures (V/V) at 0°C. The photolysis produces benzyl carbocations that react with nucleophiles. The reaction products were analyzed by gas chromatography or liquid chromatography. From the amounts of products the relative values of rate constants of reactions of benzyl carbocation with nucleophiles N and water k(N)/k(H2O) were calculated. Benzyl carbocation reacts with I−, Br−, Cl−, and Ac− ions with approximately diffusion‐controlled rate. A value of 2.4 × 107 dm3 mol−1 s−1 for the rate constant k(H2O) and a lifetime of 0.7 ns were estimated for benzyl carbocation in the aqueous solution.
Rate constants for the reaction OH + CO as functions of temperature and water concentration
Authors: Beno Mary F. , Jonah Charles D. , Mulac William A. 
Published: January 2005

AbstractRate constants for the reaction OH + CO have been measured as functions of temperature (340–1220 K) and water concentration in the presence of 1 atm of argon. Results at zero water concentration yield the expression, log kƒ (cm3 molecule−1 S−1) = −12.96 + 4.7 × 10−4 T, for the reaction rate constant as a function of temperature. These results are in very good agreement with previous direct measurements and in reasonable agreement with flame and shock tube measurements. Explanations are offered for the involvement of the water molecule in the present experiments and earlier measurements from this laboratory throughout the entire temperature range. Results are consistent with previous results showing little, if any, pressure effect of Ar on the reaction up to 1 atm of Ar.
Tables of rate constants extracted from chemical kinetics and photochemical data for use in stratospheric modeling. Evaluation number 7
Authors: Demore W. B. , Margitan J. J. , Molina M. J. , Watson R. T. , Golden D. M. , Hampson R. F. , Kurylo M. J. , Howard C. J. , Ravishankara A. R. 
Published: January 2005

AbstractThese tables of evaluated rate constants for use in stratospheric modeling have been taken from the most recent report of the NASA Panel that has been periodically producing such reviews. They are reproduced here to make a broader community aware of their existence. This article should NOT be cited, nor should these rate constants be used without consulting the full report. All citations should be to that original report (JPL Publ. 85‐37), which contains extensive documentation and discussion of the rationale of the evaluation. Copies may be obtained by requesting JPL Publ. 85‐37 from Documentation Services, 111‐116B, Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109.
Kinetics of Ce(IV) oxidation of α‐keto acids in sulfuric‐perchloric acid media
Authors: Saraç A. Sezai 
Published: January 2005

AbstractThe rates of oxidation of four α‐keto acids, glyoxylic, pyruvic, phenylglyoxylic, and 2‐oxobutyric acids by Cerium(IV) in H2SO4HaHSO4 and H2SO4HClO4 solutions, have been studied spectrophotometrically. The rate data suggest that CeSO is the most reactive of the Cerium(IV)‐sulfate complexes present in the H2SO4NaHSO4 and H2SO4HClO4 systems. The oxidation reaction is proposed to be a one‐electron process with the rate‐determining step being the decomposition of a α‐ketoacid‐Cerium(IV) complex to a free radical and carbon dioxide through a transition state.
A reevaluation of low temperature experimental rate data for the reactions of O atoms with methane, ethane, and neopentane
Authors: Cohen N. 
Published: January 2005

AbstractThe experimental data for the reactions of oxygen atoms with methane, ethane, and neopentane at temperatures below ca. 600 K have been reexamined. In the case of CH4 and C2H6 reactions, detailed computer models have been assembled to test the assumptions regarding stoichiometries that were made in the original studies in order to derive elementary rate coefficients from the experimentally observed reaction rates. It was found in both cases that the measurements are especially sensitive to secondary reactions not taken into account and impurities in the reagent alkane. Because the original reports did not include sufficient experimental details, it is not now possible to correct their results quantitatively. However, it appears, qualitatively, that the values for the O + CH4 and O + C2H6 rate coefficients were overestimated by factors of approximately 2 to 3 in the 250–400 K temperature range, with the error increasing as T decreases. Although the experimental results for the O + neopentane reaction are not as sensitive to the same kinds of complications, a comparison of the low‐temperature measurements with those for the O + ethane reaction suggests that the previously recommended rate coefficients, based on the data of Herron and Huie, are probably also too high by a factor of 2 to 3.
Stopped‐flow investigations of the reaction kinetics of carbon dioxide with some primary and secondary alkanolamines in aqueous solutions
Authors: Barth D. , Tondre C. , Delpuech J. ‐J. 
Published: January 2005

AbstractThe reaction kinetics of carbon dioxide with four alkanolamines of industrial importance (MEA, DGA, DEA, and DIPA) have been investigated with the aid of the stopped‐flow technique, allowing the determination of rate constants for carbamates formation. The constants obtained for MEA at 20°C and 25°C are in good agreement with recent literature data. The kinetic behavior of DGA was found to be almost identical to that of MEA.The rate constants obtained for DIPA at 25°C (54 M−1 s−1) is half as large as that for DEA (110 M−1 s−1). The former one is satisfactorily compared with the recent values proposed by Blauwhoff et al. Activation energies have also been obtained for DEA (23.2 kJ mol−1) and for DIPA (58.7 kJ mol−1) and their mechanistic implications are discussed in relation with the relevanceof a rate‐determining proton transfer step in the process of carbamate formation.
Kinetics and mechanism of the pyrolysis of 1‐Chloro‐1, 1‐difluoroethane in the presence of chlorine
Authors: Huybrechts G. , Hubin Y. 
Published: January 2005

AbstractThe first stage thermal reactions of CF2CICH3 in the presence of chlorine have been studied between 554 and 614 K. These are
equation image
and

Rate equations derived from a radical mechanism are shown to fit the experimental results. Values of Arrhenius parameters for the decomposition of the CF2ClCH2. radical and its reactions with Cl2 and Cl are given.
Rate constants of O2(1Δg)
Authors: Raja Nalini , Arora P. K. , Chatha J. P. S. 
Published: January 2005

AbstractThe rate constants of O2(1Δg) with aliphatic alcohols, terpenes, unsaturated hydrocarbons, chlorinated hydrocarbons, oxygen, and diamines have been studied in thepresence of NO2. The rate constants for oxygen, 1,2‐ethane diamine, and 1,2‐propane diamine are (9.9 ± 0.4) × 102, (8.7 ± 0.7) × 104, and (1.4 ± 0.3) × 104 1/mol/s, respectively. The rate constants for all other compounds are less than the oxygen rate constant.