Theoretical study of mechanisms and kinetics of reactions of the O(3P) atom with alkyl hydroperoxides (ROOH) where (R = CH3 & C2H5)

An analysis of O(P-3) reaction mechanisms and kinetics with CH3OOH and CH3CH2OOH has been examined. Potential energy diagrams for the named reactions have been evaluated at the W1 and CCSD(T)/aug-cc-pVTZ// MP2/aug-cc-pVTZ levels of theory. For the two reactions, a total of seven abstraction channels have been described. The reaction enthalpies and standard reaction Gibbs free energy are calculated at the W1 level. The kinetic study is conducted within the temperature range of 210-350 K using transition state theory (TST), TST with Wigner correction (TST/W), and TST with zero curvature tunneling (TST/ZCT). The rate coefficients were also calculated using canonical variational transition state theory (CVT), CVT with zero curvature tunneling (CVT/ZCT), and CVT with small curvature tunneling (CVT/SCT). Branching ratios have been computed using the CVT/SCT rate coefficients. Hydrogen abstraction from the hydroxyl group is identified as a significant pathway in both reactions.