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Comment: A re‐evaluation of the rate constant for abstraction of hydrogen from isobutane by methyl radicals
Author(s) -
Zhang H.X.,
Back M. H.
Publication year - 1990
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.550220509
Subject(s) - isobutane , chemistry , radical , hydrogen atom abstraction , reaction rate constant , abstraction , hydrogen , hydrogen atom , range (aeronautics) , constant (computer programming) , atmospheric temperature range , computational chemistry , thermodynamics , organic chemistry , kinetics , physics , group (periodic table) , quantum mechanics , philosophy , materials science , epistemology , computer science , composite material , programming language , catalysis
The rate constant for abstraction of hydrogen from isobutane by methyl radicals has been re‐examined making use of new measurements at temperatures above 660 K. Most of the data over the temperature range 300–855 K can be accommodated by the following values for the rate constants for abstraction from primary and tertiary hydrogen atoms:\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm log}k_{4T} ({\rm L mol}^{{\rm - 1}} {\rm s}^{{\rm - 1}}) = 8.15 - \frac{{33800}}{{2.3RT}}\quad (R = 8.314{\rm J mol}^{{\rm - 1}} {\rm K}^{{\rm - 1}}) $$\enddocument}\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm log}k_{4P} ({\rm L mol}^{{\rm - 1}} {\rm s}^{{\rm - 1}}) = 8.88 - \frac{{48400}}{{2.3RT}}$$\enddocument}This activation energy for abstraction of the tertiary hydrogen atom in isobutane is essentially the same as expressed in a previous evaluation, which considered data only below 500 K, but the magnitude of the rate constant is about 0.25 log units greater.