摘要:

AbstractThe pyrolysis of methyl 4‐bromocrotonate in the temperature range 300–340°C and pressure range 74–170 torr has been shown to be homogeneous, unimolecular, and to follow a first‐order rate law. The reaction was carried out in a static system, seasoned with allyl bromide, and in the presence of the radical chain exhibitor toluene. The rate coefficients are represented by the Arrhenius expression: logk1(s−1) = (13.30 ± 0.66) − (185.2 ± 7.5) kJ mol−1(2.303RT)−1. The carbomethoxy group appears to provide anchimeric assistance in the process of dehydrobromination and lactone products formation. The partial rates for the parallel reaction have been estimated, reported, and discussed. The pyrolysis elimination is explained in terms of an intimate ion pair

ISSN:0538-8066    

DOI:10.1002/kin.550200102

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractVinylacetylene and 2‐butyne mixtures were pyrolyzed at 350–450°C in the absence and presence of O2and NO. The major product of the reaction is a polymer, but o‐xylene is also produced and was studied as the species of interest. The C8H10formation rate is first‐order in C4H4and C4H6. The rate coefficient is best fitted by\documentclass{article}\pagestyle{empty}\begin{document}$$\log {\rm [}k{\rm (C}_{\rm 8} {\rm H}_{{\rm 10}}),{\rm M}^{{\rm -1}}\, {\rm s}^{{\rm - 1}}] = (4.33 \pm 0.58) - (80.1 \pm 7.4)/2.3RT$$\end{document}though it is not inconsistent with\documentclass{article}\pagestyle{empty}\begin{document}$$\log {\rm [}k{\rm (C}_{\rm 8} {\rm H}_{{\rm 10}}),{\rm M}^{{\rm - 1}}\, {\rm s}^{{\rm - 1}}] = (7.93) - (125.9)/2.3RT$$\end{document}whereRis the ideal gas constant in kJ/mol‐K. O‐xylene formation occurs by two processes: a concerted molecular mechanism (⋍67%) and a singlet diradical me

ISSN:0538-8066    

DOI:10.1002/kin.550200103

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550200104

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractElementary bimolecular processes that involve formation of a chemically activated intermediate species are common. We address the general problem of modeling these processes and describe the necessary and sufficient information that must be specified to assure that a kinetics model will extrapolate the rate constants for those reactions over wide ranges of temperature and pressure. The approach is illustrated for the system centered around the HOCO intermediate. Here, specification of the temperature and pressure dependence of three rate constants,k(T,P) and the temperature dependence of two equilibrium constants,K(T), is necessary and sufficient, viz:Rate constants are cast in the form of an analytical expression, suggested by Troe, and appropriate parameters are tabulated.

ISSN:0538-8066    

DOI:10.1002/kin.550200105

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractAbsolute rate constants were determined for the gas phase reactions of OH radicals with a series of linear aliphatic ethers using the flash photolysis resonance fluorescence technique. Experiments were performed over the temperature range 240–440 K at total pressures (using Ar diluent gas) between 25–50 Torr. The kinetic data for dimethylether (k1), diethylether (k2), and dipropylether (k3) were used to derive the Arrhenius expressions\documentclass{article}\pagestyle{empty}\begin{document}$$k_1 = (6.7 \pm 1.5) \times 10^{- 12} {\rm \,exp[- (300} \pm {\rm 70)/}T]{\rm \,cm}^{\rm 3}\, {\rm \,molecule}^{{\rm - 1}}\, {\rm s}^{{\rm - 1}}$$\end{document}\documentclass{article}\pagestyle{empty}\begin{document}$$k_2 = (5.6 \pm 1.7) \times 10^{- 12} {\rm \,exp[(270} \pm 10{\rm 0)/}T]{\rm \,cm}^{\rm 3}\, {\rm \,molecule}^{{\rm - 1}}\, {\rm s}^{{\rm - 1}}$$\end{document}and\documentclass{article}\pagestyle{empty}\begin{document}$$k_3 = (11 \pm 3) \times 10^{- 1 2} {\rm \,exp[(150} \pm 8{\rm 0)/}T]{\rm \,cm}^{\rm 3}\, {\rm \,molecule}^{{\rm - 1}}\, {\rm s}^{{\rm - 1}}$$\end{document}At 296 K, the measured rate constants (in units of 10−13cm3molecule−1s−1) were:k1= (24.9 ± 2.2),k2= (136 ± 9), andk3= (180 ± 22). Room temperature rate constants for the OH reactions with several other aliphatic ethers were also measured. These were (in the above units): di‐n‐butylether, (278 ± 36); di‐n‐pentylether, (347 ± 20); ethyleneoxide, (0.95 ± 0.05); propyleneoxide, (4.95 ± 0.52); and tetrahydrofuran, (178 ± 16). The results are discussed in terms of the mechanisms for these reactions and are compared to

ISSN:0538-8066    

DOI:10.1002/kin.550200106

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractAcuchem is a program for solving the system of differential equations describing the temporal behavior of spatially homogeneous, isothermal, multicomponent chemical reaction systems. It is designed to provide modelers, data evaluators, and laboratory scientists with an easy to use program for modeling complex chemical reactions, and for presenting the results in tabular or graphical form. The program is described and some examples of its application given. Acuchem is designed to operate on the IBM Personal Computer family and other compatible microcomputers, and is available in a compiled version on a floppy disk.

ISSN:0538-8066    

DOI:10.1002/kin.550200107

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractThe rate constants for the reactions Cl + CH3OD → CH2OD + HCl (1) and CH2OH + O2→ HO2+ H2CO (2) have been determined in a discharge flow system near 1 torr pressure with detection of radical and molecular species using collision‐free sampling mass spectrometry. The rate constantk1, determined from the decay of CH3OD in the presence of excess Cl, is (5.1 ± 1.0) × 10−11cm3s−1. This is in reasonable agreement with the only previous measurement ofk1. The CH2OH radical was produced by reaction (1) and its reaction with O2was studied by monitoring the decay of the CH2OH radical in the presence of excess O2. The result isk2= (8.6 ± 2.0) × 10−12cm3s−1. Previous estimates ofk2have differed by nearly an order of magnitude, and our value fork2supports the more r

ISSN:0538-8066    

DOI:10.1002/kin.550200108

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractN2(A3Σ u+), the lowest electronically excited state of N2, has a long and distinguished history due to its role in nitrogen discharges and the nitrogen afterglow. Recently, the production of N2(A) via photolysis and chemiluminescent reactions has been newly explored, and new facets of its reactivity have been uncovered. N2(A) is unusual, in that its deactivation probability in collision with small molecules spans many orders of magnitude, and is frequently strongly dependent on the vibrational content of N2(A). This behavior and the observed product channels can be understood in terms of a simple model for the energy transfer process. Brief comparison with reactions of related species is ma

ISSN:0538-8066    

DOI:10.1002/kin.550200109

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550200101

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY