摘要:

AbstractThe kinetics of the gas‐phase reactions of the OH radical with (C2H5O)3PO and (CH3O)2P(S)Cl and of the reactions of NO3radicals and O3with (CH3O)2P(S)Cl have been studied at room temperature. Using a relative rate technique, the rate constants determined for the reactions of the OH radical with (C2H5O)3PO and (CH3O)2P(S)Cl at 296 ± 2 K and 740 torr total pressure of air were (5.53 ± 0.35) × 10−11and (5.96 ± 0.38) × 10−11cm3molecule−1s−1, respectively. Upper limits to the rate constants for the NO3radical and O3reactions with (CH3O)2P(S)Cl of<3 × 10−14cm3molecule−1s−1and<2 × 10−19cm3molecule−1s−1, respectively, were obtained. These data are compared and discussed with previous literature data fo

ISSN:0538-8066    

DOI:10.1002/kin.550200402

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractThe rate constant for the HO2self reaction has been determined as a function of methanol vapor concentration at 278 K and 299 K. A molecular modulation technique was used in which HO2radicals were photochemically produced in flowing gas mixtures comprised of Cl2, CH3OH, N2and O2with HO2monitored in the UV at 220 nm. A positive linear dependence of the second order rate constant on methanol concentration was found and this effect increased with decreasing temperature. The rate constant for the HO2self reaction can be described by\documentclass{article}\pagestyle{empty}\begin{document}$$k = 9.2 \cdot 10^{- 15} {\rm \,exp(1700/}T)\,+ \,2.1 \cdot 10^{- 34} {\rm \,exp(3000/}T)[{\rm CH}_{\rm 3} {\rm OH]cm}^{\rm 3}\, {\rm \,molecule}^{{\rm - 1}} {\rm \,s}^{{\rm - 1}}$$\end{document}in nitrogen at atmospheric pressure and in the methanol concentration range 1 · 1016to 3 · 1017molecules cm

ISSN:0538-8066    

DOI:10.1002/kin.550200403

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractStudies of the reaction of Br + propylene to produce HBr and allyl radical were made using VLPR (Very Low Pressure Reactor) over the range 263–363 K. Apparent bimolecular rate constantsk 1appwere found to vary in an inverse manner with the initial concentration of bromine atoms introduced into the reactor. Plots ofk 1appagainst [Br] 0−1give straight lines whose intercepts were taken to be the true bimolecular, metathesis rate constantk1. The reaction scheme is\documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{rcl} {\rm Br} + {\rm C}_{\rm 3} {\rm H}_6& \stackrel{1} {\rightleftharpoons}& {\rm HBr} + {\rm allyl}\\ {\rm Br} + {\rm allyl} & \stackrel{2} {\longrightarrow}& {\rm HBr} + {\rm allene}\\ \end{array} $$\end{document}wherek2≫k1andk−1[HBr] is negligibly small under our conditions.Arrhenius parameters fork1were assigned for linear and bent transition states and shown to give excellent fits to the observed intercepts.\documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{rcl} {{\rm linear:}}\quad \log {(k_1 /{\rm cm}^3\, {\rm mol}^{{\rm - 1}}\,{\rm s}^{{\rm - 1}})} &=& 12.1 - 3.5/\theta\\ {{\rm bent:}}\quad \log {(k_1 /{\rm cm}^3\, {\rm mol}^{{\rm - 1}}\, {\rm s}^{{\rm - 1}})} &=& 12.7 - 4.4/\theta \end{array} $$\end{document}where θ = 2.303RT(kcal mol−1).The dependence ofk 1appon [Br] 0−1is accounted for in terms of the reactivity of Br* (2P1/2) produced in the microwave discharge. The activation energy for the metathesis reaction of Br* with propylene is

ISSN:0538-8066    

DOI:10.1002/kin.550200404

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractIt is shown that the master equation describing fall‐off effects in unimolecular and recombination reactions, with angular momentum (J) conservation taken into account, can be solved exactly if the assumption is made that the probability of collisional energy transfer inJis independent of initial state; this assumption is shown to be physically acceptable (from general conservation considerations and from trajectory calculations) for typical neutral radical recombination and decomposition reactions. This leads to aJ‐averaged master equation which can be readily solved by standard means. Illustrative computations using this treatment are presen

ISSN:0538-8066    

DOI:10.1002/kin.550200405

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractThe temperature dependencies of the rate constants for the gas phase reactions of OH radicals with a series of carboxylic acids were measured in a flash photolysis resonance fluorescence apparatus over the temperature range 240–440 K. The data at total pressures (using Ar diluent gas) between 25–50 torr for acetic acid (k1), propionic acid (k2), and i‐butyric acid (k3) were used to derive the Arrhenius expressions\documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{rcl} k_1 &=& (1.3\, \pm \,0.1)\, \times \,10^{- 12} {\rm \,exp[- (170}\, \pm \,2{\rm 0)/}T]{\rm \,cm}^{\rm 3}\, {\rm \,molecule}^{{\rm - 1}}\, {\rm \,s}^{{\rm -1}}\\ k_2 &=& (1.8\, \pm \,0.2)\, \times \,10^{- 12} {\rm \,exp[- (120}\, \pm \,3{\rm 0)/}T]{\rm \,cm}^{\rm 3}\, {\rm \,molecule}^{{\rm - 1}}\, {\rm \,s}^{{\rm - 1}} \end{array} $$\end{document}and\documentclass{article}\pagestyle{empty}\begin{document}$$k_3 = (2.6 \pm 0.2) \times 10^{- 12}\, {\rm exp[- (70} \pm 25{\rm)/}T]{\rm \,cm}^{\rm 3}\, {\rm \,molecule}^{{\rm - 1}}\, {\rm s}^{{\rm - 1}}$$\end{document}At 298 K, the measured rate constants (in units of 10−12cm3molecule−1s−1) were:k1= (0.74 ± 0.06),k2= (1.22 ± 0.12), andk3= (2.00 ± 0.20). In addition a rate constant of (0.37 ± 0.04), in the above units, was determined for the reaction of OH with formic acid. The error limits cited above are 2σ from the linear least squares analyses. These results are discussed in terms of the mechanisms for these reactions and are compared to

ISSN:0538-8066    

DOI:10.1002/kin.550200406

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550200407

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550200401

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY