Kinetic study of the reaction of chlorine atoms with bromomethane and D-bromomethane in the gas phase

The kinetics of the gas-phase reactions of chlorine atoms with bromomethane CH3Br and D-bromomethane CD3Br was studied experimentally. The relative rate method was applied using Cl + CH4 as the reference reaction. The rate constants for H-abstraction from CH3Br (kH) and D-abstraction from CD3Br (kD) were measured in the temperature range of 298–527 K and at a total pressure of 100 Torr. The temperature dependencies of the rate constants are described by the expressions: kH = (1.43 ± 0.22) × 10−11 × exp(−1040 ± 30/T) and kD = (1.36 ± 0.31)×10−11 × exp(−1595 ± 30/T) cm3 molecule−1 s−1. The kinetic isotope effect, described by the ratio kH/kD, was found to be (1.07 ± 0.14) × exp(555 ± 20/T).