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

The kinetics of the gas-phase reactions of chlorine atoms with dichloromethane (CH2Cl2) and D-dichloromethane (CD2Cl2) was studied using the relative rate method with Cl + CH3Br as the reference reaction. The rate constants for H-abstraction from CH2Cl2 (kH) and D-abstraction from CD2Cl2 (kD) were measured in the temperature range of 298–527 K and at a total pressure of 100 Torr using N2 as a diluent. The temperature dependencies of the rate constants (with the 2σ error limits) are described by the expressions: kH = (8.69 ± 0.82) × 10−12 × exp(−955 ± 20/T) and kD = (6.98 ± 0.91) × 10−12 × exp(−1285 ± 25/T) cm3 molecule−1 s−1. The kinetic isotope effect, described by the ratio kH/kD, was found of 3.8 ± 0.2 at room temperature.