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

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. x(ij) 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 2000K and compared with available experimental data. The computed rate constants for the reactions R1, R2 and R3 are fitted to the equation k(T) = AT(n)exp [ - E(T + T-0)/(T-2 + T-0(2))].