Kinetics of Reactions of H Atoms With Methane and Chlorinated Methanes

Published

January 1, 2001

Author(s)

M G. Bryukov, I R. Slagle, Vadim D. Knyazev

Abstract

The reactions of H atoms with methane, four chlorinated methanes, and isobutene have been studied experimentally using the Discharge Flow / Resonance Fluorescence technique over wide ranges of temperatures. The rate constants were obtained in direct experiments as functions of temperature. The experimentally obtained activation energies of the reactions of H atoms with chlorinated methanes demonstrate a correlation with the enthalpies of the reactions. Transition-state-theory reaction models were created on the basis of ab initio calculations, the Marcus expression for correlation between reaction barriers and reaction energetics, and analysis of experimental data. It is demonstrated that the formalism based on the Marcus expression adequately describes the observed temperature dependencies of the rate constants of the overall reactions. According to the models, abstraction by H atoms of hydrogen atoms from chloromethanes is an important process accounting for significant fractions of the overall rate constants. The models result in expressions for the rate constants of Cl- and H-atom abstraction channels and the corresponding reverse reactions over wide ranges of temperatures.

Citation

Journal of Physical Chemistry A

Volume

105

Pub Type

Journals

Keywords

chlorinated methanes, hydrogen atoms, kinetics, Marcus equation, methane

Citation

Bryukov, M. , Slagle, I. and Knyazev, V. (2001), Kinetics of Reactions of H Atoms With Methane and Chlorinated Methanes, Journal of Physical Chemistry A (Accessed April 25, 2024)