Hydrogen abstraction reactions of hydroxyl radicals with 1,1,2,2-tetrachloroethane, 1,1,1,2-tetrachloroethane and pentachloroethane studied by using semi-classical transition state theory

Abstract

The hydrogen abstraction reactions by OH radicals from CHCl2CHCl2 (R1), CH2ClCCl3 (R2) and C2HCl5 (R3) are investigated theoretically by semi-classical transition state theory. Many high-level density functional, ab initio and combinatory electronic structure calculation methods are used to evaluate the energies and ro-vibrational properties of the stationary points for the title reactions. xij vibrational anharmonicity coefficients, needed for semi-classical transition state theory, are calculated at the KMLYP/cc-pVTZ level of theory. Thermal rate coefficients are computed over the temperature range from 200 to 2000 K and compared with available experimental data. The computed rate constants for the reactions R1, R2 and R3 are fitted to the equation k(T) = ATnexp [ − E(T + T0)/(T2 + T20)].