Theoretical study on the mechanism and thermodynamic of methanethiol and ozone reaction

Reaction mechanism of methanethiol oxidation with ozone are carried out using the B3LYP and CCSD(T) theoretical approaches in connection with the 6-311++G(3df,3pd) basis set. Results confirm six kinds of products, P1–P6, which have enough thermodynamic stability. In thermodynamic viewpoint, the P6 product is the most favored adduct of the CH3SH + O3 gas phase reaction at atmospheric pressure and 298.15 K temperature. The P6 adduct, CH3OH + SO2, is spontaneous and exothermic with −146.47 and −146.81 kcal/mol in Gibbs free energy and enthalpy of reaction at the B3LYP level, respectively. In kinetic viewpoint, the CH2S + H2O2 + O2, P2 adduct, as final product after passing two transition state low level is the most favorite path.