摘要:

AbstractRate constants for the gas‐phase reactions of hydroxyl radicals and chlorine atoms with aliphatic alcohols and ethers have been determined at 298 ± 2 K and at a total pressure of 1 atmosphere. The OH radical rate data were obtained using both the absolute technique of pulse radiolysis combined with kinetic UV spectroscopy and a conventional photolytic relative rate method. The Cl atom rate constants were measured using only the relative rate method. Values of the rate constants in units of 10−12cm3molecule−1s−1are:The above relative rate constants are based on the values of

ISSN:0538-8066    

DOI:10.1002/kin.550221102

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe pyrolyses ofp‐nitrophenylt‐butyl ether,p‐methoxyphenylt‐butyl ether,p‐aminophenylt‐butyl ether,p‐nitrophenylt‐butyl sulfide, and propargylt‐butyl sulfide have been studied in a stirred‐flow reactor over the temperature range 430–530°C and pressures in the range 7–14 torr, using toluene as carrier gas. The reactions yielded between 90 and 99% isobutene plus the corresponding phenol, thiophenol, or thiol as products. The first order rate coefficients for reactant consumption, based on isobutene production, followed the Arrhenius equationsp‐nitrophenylt‐butyl ether\documentclass{article}\pagestyle{empty}\begin{document}$$ k({\rm s}^{ - 1}) = 10^{12.79 \pm 0.24} {\rm exp}(- 179 \pm 3{\rm kJ/mol}RT) $$\end{document}p‐methoxyphenylt‐butyl ether\documentclass{article}\pagestyle{empty}\begin{document}$$ k({\rm s}^{ - 1}) = 10^{14.50 \pm 0.30} {\rm exp}(- 210 \pm 4{\rm kJ/mol}RT) $$\end{document}p‐aminophenylt‐butyl ether:\documentclass{article}\pagestyle{empty}\begin{document}$$ k({\rm s}^{ - 1}) = 10^{14.59 \pm 0.28} {\rm exp}(- 208 \pm 4{\rm kJ/mol}RT) $$\end{document}p‐nitrophenylt‐butyl sulfide\documentclass{article}\pagestyle{empty}\begin{document}$$ k({\rm s}^{ - 1}) = 10^{12.12 \pm 0.27} {\rm exp}(- 185 \pm 4{\rm kJ/mol}RT) $$\end{document}propargylt‐‐butyl sulfide:\documentclass{article}\pagestyle{empty}\begin{document}$$ k({\rm s}^{ - 1}) = 10^{13.79 \pm 0.24} {\rm exp}(- 204 \pm 3{\rm kJ/mol}RT) $$\end{document}The results support a unimolecular elimination of the isobutene involving

ISSN:0538-8066    

DOI:10.1002/kin.550221103

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe induction period observed in thecis‐RuCl2(DMSO)4catalyzed oxidation of thioethers (S) to sulfoxides byN‐methylmorpholineN‐oxide (NMO) is attributed to the rate of formation of the active species viz. RuCl2(DMSO)3S. Cyclic voltammetric studies indicate formation of the RuIV= 0 species. Based on the variable orders in NMO and first order in each of the other reactants, a mechanism is proposed where the active species generatedin situreacts with NMO in a slow step to form RuIVoxo complex which then decomposes to give the pr

ISSN:0538-8066    

DOI:10.1002/kin.550221104

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe kinetics of the reaction of benzyl bromide with thiourea was studied in different pure (protic and aprotic) solvents and the rate data was correlated using linear multiple regression analysis. From the regression coefficients which describe the susceptibility of rate to different solvent parameters, information regarding the solvent‐reagent, and the solvent‐intermediate interactions was obtained and solvation models were proposed.Applicability of the Swain‐Scott free energy relationship was tested using different sulphur nucleophiles in acetonitrile solvent and the nucleophilicity constant ofN‐acetylthiourea was computed as 2.74 from the regressi

ISSN:0538-8066    

DOI:10.1002/kin.550221105

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe gas phase reaction of OH radicals with hydrogen iodide (HI) has been studied using a Laser Photolysis‐Resonance Fluorescence (LP‐RF) apparatus, recently developed in our group. The measured rate constant at 298 K was (2.7 ± 0.2) × 10−11cm3molecule−1s−1. This rate constant is compared with the ones of the reactions OH + HCl and OH + HBr. The role of the reaction OH + HI in marine tropospheric chemistry is discussed.In addition, the LP‐RF apparatus was tested and validated by measuring the following rate constants (in cm3molecule−1s−1units):

ISSN:0538-8066    

DOI:10.1002/kin.550221106

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe ultraviolet absorption spectrum of the neopentylperoxy radical, (CH3)3CCH2O2(or C5H11O2), and the kinetics of its self‐reaction have been studied in the gas phase using a flash photolysis technique. The room temperature absorption cross‐section at 250 nm was determined to be\documentclass{article}\pagestyle{empty}\begin{document}$$ \sigma _{{\rm C}_{\rm 5} {\rm H}_{11} {\rm O}_{\rm 2}} (250{\rm nm}) = (5.18 \pm 0.78) \times 10^{ - 18} {\rm cm}^{\rm 2} {\rm molecule}^{ - 1} $$\end{document}and was used to normalize the radical absorption spectrum between 210 and 300 nm. Detailed modeling of the self‐reaction system was used to interpret the transient absorption kinetic decay curves over the temperature range 228–380 K, at total pressures between 25 and 100 torr. The results are discussed in relation to previous measurements of alkylperoxy radical spectra and k

ISSN:0538-8066    

DOI:10.1002/kin.550221107

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe reactions of ℓ‐C3H3+(propargylium cation) with acetylene and diacetylene have been modeled kinetically. Data were obtained from Fourier Transform Ion Cyclotron Resonance (FTICR) experiments on these systems, which are themselves models for soot particle initiation. Acetylene forms an encounter complex with ℓ‐C3H3+, but, in the absence of a third body collision, the complex decomposes to acetylene andc‐C3H3+(cyclopropenylium cation) at about 1/3 the rate it decomposes to acetylene and ℓ‐C3H3+, in spite of the fact thatc‐C3H3+is ca. 115 kJ/mol more stable than ℓ‐C3H3+. The encounter complex is long enough lived, and energetic enough, to scramble deuterium in reactions between ℓ‐C3H3+and C2D2. These reactions have been successfully modeled, yielding a nearly statistical distribution of deuterium, and a rather large kinetic isotope effect. The more complex reactions of ℓ‐C3H3+with diacety

ISSN:0538-8066    

DOI:10.1002/kin.550221108

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractData are presented demonstrating the validity of a new method of measuring pseudo‐order rate constants, based on an iterative computational procedure long in use for kinetic conditions where the “infinity” value is not experimentally accessible. This new method requires that the kinetic order be known for the limiting reagent, but is otherwise general. It allows measurement of the pseudo‐order rate constant even at a ratio of reactants of 1:1 by maximizing the fit of three half‐lives of data to the appropriate pseudo‐order kinetic equation, treating the “infinity” valu

ISSN:0538-8066    

DOI:10.1002/kin.550221109

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550221101

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY