摘要:

AbstractThe rate constant of the reaction between OH and OCS in helium over the temperature range 255–483 K has been determined using the discharge flow‐resonance fluorescence technique. The OCS has been carefully purified to avoid interference from H2S and CO impurities. An FTIR with a multireflection cell was used to determine the impurity concentrations and the purified sample was found to contain less than 0.005% of H2S. At 300 K, the rate constant was determined to be (2.0 ±0.40.8) × 10−15cm3molecule−1s−1. Although the rate constants showed slight positive deviation at lower temperatures, thev can be satisfactorily fitted by the Arrhenius equation,k= 1.13 × 10−13exp(−1200/T) cm3molecule−1s−1. No pressure dependence was observed at all temperatures, nor was O2enhancement observed under our exp

ISSN:0538-8066    

DOI:10.1002/kin.550181202

出版商:John Wiley&Sons, Inc.    

年代:1986

数据来源: WILEY

摘要:

AbstractTrichloromethylperoxyl radicals were produced by pulse radiolysis of air saturated solutions containing CCl4. The rate constants for the reaction of CCl3O2radicals with zinc tetraphenylporphyrin (ZnTPP) were determined in various solvents. They were found to vary between 3 × 107and 3 × 109M−1s−1. The changes in rate constants result from complexation of ZnTPP with the different solvents, but did not correspond to changes in redox potential of ZnTPP. The rate constants were found to depend on the strength of the axial complexation, indicating an inner sphere mechanism whereby the radical binds to the metal prior to electron tra

ISSN:0538-8066    

DOI:10.1002/kin.550181203

出版商:John Wiley&Sons, Inc.    

年代:1986

数据来源: WILEY

摘要:

AbstractThe thermal addition of CF3O3CF3(T)to CF2CCl2(E)has been investigated between 49.6 and 69.5°C. The initial pressure of CF3O3CF3was varied between 7 and 240 torr and that of CF2CCl2between 4 and 600 torr. Four products of formula CF3O(E)jOOCF3, wherej= 1 → 4 are formed. The sum of the products Σ i = 14CF3O(E)jOOCF3is equal to the amount of trioxide decomposed.The reaction is homogeneous. Its rate is not affected by the total pressure and the presence of inert gas. It is a free radical telomerization with four basic steps: thermal decomposition of CF3O3CF3into CF3O.and CF3O2., chain initiation by addition of CF3O.to olefin incorporated in, and telomeric radicals termination.The consumption of alkene is well represented by the equation:\documentclass{article}\pagestyle{empty}\begin{document}$$ - d[E]/dt = k_1 [T]\left\{ {1 + \sum\limits_{j = 1}^3 {\prod\limits_{i = 1}^j {[1 + (k_{t_1 } k_1^{1/2} /k_{gi} } k_t^{1/2})([T]^{1/2} /[E])]^{ - 1} } } \right\} $$\end{document}where (d[E]/d[T]) =\documentclass{article}\pagestyle{empty}\begin{document}$$ \bar n $$\end{document}is the mean chain length of telomerization.\documentclass{article}\pagestyle{empty}\begin{document}$$ \bar n $$\end{document}varies from 1.45 at 1.5 torr ofEto 3.3 at 400 torr ofE. Above this pressureEhas no influence on\documentclass{article}\pagestyle{empty}\begin{document}$$ \bar n $$\end{document}.The estimated value of the constant for the addition of telomeric radicals to alkene is:\documentclass{article}\pagestyle{empty}\begin{document}$$ k_g \simeq 8.6 \pm 6.0 \times 10^4 \exp ( - 2300 \pm 200{\rm col mol}^{{\rm - 1}} /RT){\rm M}^{{\rm - 1}} {\rm s}^{{\rm - 1}} $$\end{doc

ISSN:0538-8066    

DOI:10.1002/kin.550181204

出版商:John Wiley&Sons, Inc.    

年代:1986

数据来源: WILEY

摘要:

AbstractThe gas phase thermal isomerization of 4‐acetyl−5‐methyl‐isoxazole affords 3‐cyano−2,4‐pentanedione as the only product in good agreement with previous proposed isomerization mechanism for isoxazoles. On the other hand, kinetic parameters and MO theoretical calculations do not agree with those previously reported. An alternative reaction mechanism which explains this fact

ISSN:0538-8066    

DOI:10.1002/kin.550181205

出版商:John Wiley&Sons, Inc.    

年代:1986

数据来源: WILEY

摘要:

AbstractThe thermal decomposition of ethylbenzene has been investigated behind reflected shock waves over the temperature and pressure ranges of 1350–2080 K and 0.25–0.5 atm using a 1.6% C8H10 Ne mixture. Major products of the pyrolysis are C7H8, C7H7, C6H6, C4H2, C2H4, C2H2, and CH4; C8H8appears throughout the temperature range as a minor product. Comparison of the product profiles obtained by time‐of‐flight mass spectrometry and the results of model calculations strongly supports the initiation step of β CC bond homolysis for C8H10dissociation. A 51 kinetic step reaction mechanism with 24 species was formulated to model the temperature and time dependence of the major products observed in our

ISSN:0538-8066    

DOI:10.1002/kin.550181206

出版商:John Wiley&Sons, Inc.    

年代:1986

数据来源: WILEY

摘要:

AbstractA study was conducted to measure the hydroxyl radical rate constants using a relative rate procedure in which the photolysis of methyl nitrite was the source of OH. During the course of this study, the OH rate constant was measured for a number of chlorinated solvents for which measurements have not previously been reported or for which there are few reliable measurements.Room temperature OH rate constants are presented for six chlorinated hydrocarbons (allyl chloride, benzyl chloride, chlorobenzene, epichlorohydrin, trichloroethylene, and vinylidene chloride) and four oxygenated hydrocarbons (acrolein, methacrolein, methyl ethyl ketone, and propylene oxide). Also included are OH rate constants for alkanes (ethane, propane, isobutane, and cyclohexane), alkenes (trans−2‐butene and isoprene), and aromatic hydrocarbons (benzene, toluene, o−,m−, andp‐xylene). Rate constants for compounds not previously reported include vinylidene chloride (1.49 ± 0.21 × 10−11cm3molecule−1s−1) and benzyl chloride (2.96 ± 0.15 × 10−12cm3molecule−1s−1). The analysis for chlorinated hydrocarbons included a correction for possibl

ISSN:0538-8066    

DOI:10.1002/kin.550181207

出版商:John Wiley&Sons, Inc.    

年代:1986

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550181201

出版商:John Wiley&Sons, Inc.    

年代:1986

数据来源: WILEY