Theoretical investigations on mechanisms and kinetics of methylketene with H reaction in the atmosphere.

Detailed oxidation course of H‐initiated degradation of CH3CHCO has been researched taking advantage of quantum chemical methods. Geometrical optimizations of reactants, intermediates, transition states, and products were operated at the B3LYP/6‐31++G(d,p) level. Single‐point energy computations were implemented at the CCSD(T)/cc‐pVTZ//B3LYP/6‐311++G(d,p) level. The results state clearly that the H association was more energetically beneficial than the abstraction of H, and the dominant pathway is generation of P1 (CH3CH2 + CO). Rate constants of H association reactions are computed by making use of Rice–Ramsperger–Kassel–Marcus (RRKM) program at 200–3000 K. Specifically, the total rate constant of H association reactions is 6.47 × 10−13 cm3 molecule−1 s−1 at 298 K, which is consistent with the experimental results (6.58 × 10−13 cm3 molecule−1 s−1). This research offers a thorough comprehending of the reaction mechanism involved in H‐initiated atmospheric degradation of CH3CHCO and might act as a relevant supplemental reference criteria for experimental research. [ABSTRACT FROM AUTHOR]