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The high temperature pyrolysis of ethylbenzene: Evidence for dissociation to benzyl and methyl radicals
Author(s) -
Mizerka L. J.,
Kiefer J. H.
Publication year - 1986
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.550180309
Subject(s) - chemistry , radical , ethylbenzene , dissociation (chemistry) , pyrolysis , endothermic process , photochemistry , torr , extrapolation , exothermic reaction , organic chemistry , thermodynamics , benzene , adsorption , mathematical analysis , physics , mathematics
The pyrolysis of ethylbenzene has been investigated in shock waves with the laser schlieren technique. Mixtures of 1 and 2% ethylbenzene in krypton were studied for reaction conditions of 1300‐1800 K, 70‐550 torr. At high temperatures, the initial rapid endothermic dissociation is followed by a region of net exothermic reaction, which is readily understood as arising mainly from methyl radical recombination after dissociation to methyl and benzyl radicals. The initial unimolecular dissociation rates show no detectable dependence on pressure; with Δ H 0 298 = 75.7 kcal mol −1 these rates are\documentclass{article}\pagestyle{empty}\begin{document}$$ \log k({\rm s}^{{\rm - 1}}) = 13.49 - 60.0/\theta $$\end{document}An RRKM extrapolation suggests\documentclass{article}\pagestyle{empty}\begin{document}$$ \log k_\infty ({\rm s}^{{\rm - 1}}) = (15.95 \pm 0.3) - (74.7 \pm 2)/\theta $$\end{document}in excellent agreement with previous lower temperature data.