Synthesis of Methanethiol from Methanol and Carbon Disulfide over CoKW/Al2O3 Catalysts: The Possible Reaction Network and Reaction Mechanism

Synthesis of methanethiol from methanol and carbon disulfide was catalyzed by KW/gamma-Al2O3 catalysts under different reaction conditions. A possible reaction network was put forward by investigating the effects of the molar ratio of reactants, the reaction pressure, the reaction temperature, the residence time, and in the presence of water and hydrogen sulfide on the catalytic performance. Furthermore, the relationship between the conversion of CH3OH, the yield of CH3SH and the surface acid-base properties was discussed in detail. The catalytic results measured in the laboratory scale (2ml catalysts) and those obtained in the scaling-up tests (50ml original grain catalysts) are well matched. Combined with pyridine adsorption Fourier Transform Infrared (FT-IR), CO2/NH3-Temperature Programmed Desorption (CO2/NH3-TPD), and the catalytic results, it was found that the conversion of CH3OH can be chiefly correlated with weak and moderate acid sites, while the selectivity toward CH3SH is mainly related to the weak basic sites, and the possible reaction mechanism was put forward.