摘要:

AbstractA general method has been developed for the determination of the differential energy distribution in nonthermally activated reacting systems. A series of known distributions and kinetic models has been used to test this method and to determine its efficacy. Application was then made to the kinetic data of energetic CH3CF218F formed by the substitution of F by18F produced by nuclear recoil. The distribution obtained for this activated CH3CF218F is seen to be highly energetic with a median energy of 137.6 kcal mol−1and with 33.1% of the molecules possessing energy in excess of 171 kcal mol−1. The shape of the calculated distribution suggests that there are two mechanisms for the formation of CH3CF218F from CH3CF3and18F, as well as that 62 kcal mol−1is a lower limit to the kinetic energy needed by the18F atom for this substitution to take

ISSN:0538-8066    

DOI:10.1002/kin.550190702

出版商:John Wiley&Sons, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe rates of decay of ozone in a large excess of the cycloalkene have been re‐measured by an improved experimental procedure, and the following second‐order rate constants (cm3molecule−1s−1) have been determined in synthetic air at atmospheric pressure:\documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} {{\rm O}_3 + {\rm cyclopentene} \longrightarrow {\rm products,}} & {k = (4.97 \pm 0.30) \times 10^{ - 16} {\rm at}} \\ \end{array}291.5{\rm K} $$\end{document}\documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} {{\rm O}_3 + {\rm cyclohexene} \longrightarrow {\rm products,}} & {k = (1.51 \pm 0.10) \times 10^{ - 16} {\rm at}} \\ \end{array}295{\rm K} $$\end{document}The results are discussed in relation to existing literature data on the kinetics of ozonecycloalkene re

ISSN:0538-8066    

DOI:10.1002/kin.550190703

出版商:John Wiley&Sons, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractRate constants for the reaction of oxiranes with bis/2‐hydroxyalkyl/disulfides, bis/2‐Hydroxyalkyl/sulfides, and 1,6‐Hexanediol in the presence ofN,N‐dimethylcyclohexylamine were studied at the temperature range of 50–90°C. A mechanism of these reactions has been proposed and its kinetic equation has been

ISSN:0538-8066    

DOI:10.1002/kin.550190704

出版商:John Wiley&Sons, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe following gas‐phase reactions:were studied by the competitive method with CF3I as the source of radicals. The kinetic parameters obtained in the temperature range 533–613 K and 503–613 K respectively for chlorine atom transfer reactions are given by:\documentclass{article}\pagestyle{empty}\begin{document}$$ \log k_1 /k_c ^{1/2} ({\rm cm}^{\rm 3}\, {\rm mol}^{{\rm - 1/2}} s^{ - 1/2}) = (6.19 \pm 0.10) - (16900 \pm 100)/\theta $$\end{document}\documentclass{article}\pagestyle{empty}\begin{document}$$ \log k_2 /k_c ^{1/2} ({\rm cm}^{\rm 3}\, {\rm mol}^{{\rm - 1/2}} s^{ - 1/2}) = (6.52 \pm 0.10) - (14890 \pm 100)/\theta $$\end{document}where θ = 2.303 RT (cal mol−1).The Arrhenius A values were calculated for seven chlorine atom transfer reactions (CF2Cl2, CFCl3, CCl4with CF3radicals; CF3Cl, CF2Cl2, CFCl3and CCl4with CH3radicals) by using the thermochemical kinetic version of the Transition State Theo

ISSN:0538-8066    

DOI:10.1002/kin.550190705

出版商:John Wiley&Sons, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractLaser‐controlled bimolecular isotopic exchange reactions in bromine leading to alterations in natural isotopic abundance ratios have been directly observed using laser‐modulated molecular beams and mass analysis. Several instances of selective excitation and subsequent rapid isotope exchange are observed within the 7 GHz gain curve of the exciting 514.5 nm line of an argon‐ion laser. These exchange processes are attributed to the direct photochemical participation of excited molecular states in the B3Πou+system

ISSN:0538-8066    

DOI:10.1002/kin.550190706

出版商:John Wiley&Sons, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractPublished data show that in its early stages (up to 3% decomposition), the pyrolysis ofn‐hexane in the ranges 723–823 K and 10–100 Torr is not inhibited by the olefin products, in contrast with neopentane pyrolysis which is very strongly inhibited in similar conditions. Detailed consideration of the chain mechanisms for the two pyrolyses shows that the reactivity of the chain terminating radical towards hydrogen abstraction from an allylic CH bond in product olefin is the factor which determines whether or not observable self‐inhibition occurs. Thus,n‐hexane pyrolysis, whose chain decomposition is terminated by recombination and disproportionation of ethyl, is not significantly self‐inhibited, whereas that of neopentane which is terminated by recombination of methyl is very strongly inhibited because methyl is 14× more reactive than ethyl. The implications for other alkanes are bri

ISSN:0538-8066    

DOI:10.1002/kin.550190707

出版商:John Wiley&Sons, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe pyrolysis of acetylene‐styrene mixtures has been studied from 450–550°C in a quartz reaction vessel in the absence and presence of O2or NO. The rates of disappearance of reactants and formation of adducts are first‐order in each reactant. The major product is polymer, with the adducts accounting for about 2.5% and 6.2% of the styrene removed at 450 and 550°C, respectively. The acetylene‐to‐styrene removal ratio is about 27 independent of temperature. The adducts formed are methyl indene and 1,2‐dihydronaphthalene. These are about half‐suppressed in the presence of O2or NO. The rate coefficients for reactant removal and adduct formation are:\documentclass{article}\pagestyle{empty}\begin{document}$$ \log \{ k\{ {\rm C}_{\rm 2} {\rm H}_{\rm 2} \},M^{ - 1} {\rm s}^{ - 1} \} = 7.53 \pm 0.10 - (90.6 \pm 1.5)/2.3RT $$\end{document}\documentclass{article}\pagestyle{empty}\begin{document}$$ \log \{ k\{ {\rm C}_{\rm 8} {\rm H}_{\rm 8} \},M^{ - 1} {\rm s}^{ - 1} \} = 6.63 \pm 0.60 - (98.5 \pm 8.8)/2.3{\rm }\,RT $$\end{document}\documentclass{article}\pagestyle{empty}\begin{document}$$ \log \{ k\{ {\rm C}_{{\rm 10}} {\rm H}_{{\rm 10}} \},M^{ - 1} {\rm s}^{ - 1} \} = 8.27 \pm 0.66 - (143.3 \pm 9.8)/2.3RT $$\end{document}where the activation energies are in kJ/mol and the uncertainties are one standard deviation. As the reaction proceeds, the methyl indene and 1,2‐dihydronaphthalene decompose, and indene and naphthalene are formed. In addition, an unidentified isomer of naphthalene is produced as an initial minor product, and it also decomposes as the

ISSN:0538-8066    

DOI:10.1002/kin.550190708

出版商:John Wiley&Sons, Inc.    

年代:1987

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550190701

出版商:John Wiley&Sons, Inc.    

年代:1987

数据来源: WILEY