Theoretical investigation on mechanisms and kinetics of the reactions of Cl atom with CH3OOH and CH3CH2OOH

The mechanisms and kinetics of reactions of Cl atom with CH3OOH and CH3CH2OOH are theoretically investigated via using quantum chemical methods and transition state theory. We explore six reaction pathways along the potential energy surface for the title reaction at the CCSD(T)/6-311++G(2d,p)//MP2/6-311++G(d,p) level. Additionally, the conventional transition state theory is also used to calculate rate constants of five H-abstraction channels over the temperature range of 200–300 K. The calculated kinetics demonstrate that H-abstraction from –CH3 group in CH3OOH and H-abstraction from –CH2 group in CH3CH2OOH are major reaction pathways, which involve the lowest reaction barriers of −1.05 and −1.83 kcal/mol with respect to separate reactants, respectively. However, H-abstraction from –OOH group should be taken into account at low temperature. The calculated total rate constants of the reactions CH3OOH and CH3CH2OOH with Cl atom are 3.00 × 10−11 and 1.34 × 10−10 cm3 molecule−1 s−1 at 298 K, which are in good agreement with the experimental data of 5.9 × 10−11 cm3 molecule−1 s−1 at 298 K and (1.07 ± 0.07) × 10−10 cm3 molecule−1 s−1 at 295 K, respectively.