A theoretical kinetic study of the methane’s hydrogen abstraction by chlorine at a large temperature range

Abstract

The kinetics and mechanism of methane CH₄ reaction with chlorine Cl atoms have been previously investigated using quantum theoretical calculations. In this study, we have investigated the hydrogen abstraction reaction by DFT using the CBS-QB3 method. Moreover, we have employed the Rice-Ramsperger-Kassel-Marcus theory to compute the rate constants of the reaction at a pressure of 1 atm and in the 295–1104 K temperature range. This study offers for the first time the theoretical mechanism and kinetic determination of the CH₄ + Cl reaction, over a wide temperature interval, as well as its importance in the halogenation reaction. The obtained rate constant was found to be k(T) = 7.29 × 10^‒19 × exp(‒287.65/T) cm³.molecule^‒1.s^‒1 and is in reasonable accord with that observed for C_xH_yCl, both theoretically and experimentally.