Enhanced Performance for Thiolation of Dimethyl Sulfide to Methanethiol over Al2O3-Supported HPW Catalysts

In this research, conversion of dimethyl sulfide (DMS) and hydrogen sulfide to methanethiol (MT) in the presence of Al2O3 supported HPW catalysts has been investigated. The catalyst characterization shows that Al2O3 supported HPW catalyst has the improved surface acidity of Lewis acid sites and uniform distribution of W species, which in turn enhances the catalytic performance. The supported HPW catalysts show better catalytic activity during thiolation of DMS to MT, and 5wt.% HPW is the optimum concentration in promoting the DMS thiolation, attaining approximately 20-degree lower initial reaction temperature than Al2O3. Moreover, a small amount of residual CS2 is acceptable for methionine chemical company for the sake of cost control. A mechanism of the enhanced DMS conversion at the catalyst surface is proposed: First H2S and DMS are adsorbed on lattice oxygen O2-. Then the main reaction occurs between CH3S-M and HO- M-O groups to form CH3SH.