Theoretical investigation for the reactions of hydrogen atom with dimethyl sulfide, ethyl methyl sulfide: Mechanism and kinetics properties

Rate coefficients for the CH3SCH3 + H → CH3SH + CH3• reaction (RA1), CH3CH2SCH3 + H → CH3SH + CH3CH2• reaction (RB1) [Display omitted] •The CH3S-transfer channels forming CH3SH are the dominant channels in the CH3SCH3 + H and CH3CH2SCH3 + H reactions.•The tunneling and variational effects are important for the H-abstraction channels.•The CH3CH2SCH3 + H reaction is favorable than the CH3SCH3 + H reaction. An exhaustive and theoretical analysis for the CH3SCH3 + H and CH3CH2SCH3 + H reactions has been examined using quantum chemistry theory over the temperature range of 300–1500 K. The potential energy surface was obtained by the CCSD(T)/CBS//M06-2X/cc-pVTZ theory. The overall rate coefficients have been analyzed and the energetics and reaction enthalpies were also calculated. Three kinds of reaction channels have been analyzed: hydrogen abstraction, CH3S-transfer and CH3-transfer channels. In the CH3SCH3 + H reaction, the CH3S-transfer channel forming CH3SH + CH3• is more predominant. For the CH3CH2SCH3 + H reaction, the channel forming CH3SH + CH3CH2• is kinetically more favorable compared to the other channels at low temperature region.