Friedel–Crafts Alkylation of Toluene by Methyl Mercaptan: Effect of Topology and Acidity of Zeolite Catalysts

The catalytic behaviors of zeolites with MFI, FAU, BEA, MOR, and MWW topologies and Si/Al ratios between 10 and 19 were examined in the toluene alkylation by methyl mercaptan (CH3SH). Over all catalysts, at 375 °C, the reagents have been primarily consumed in alkylation reactions, and only less than 2% of CH3SH led to the formation of light hydrocarbons. Based on extensive experiments, we showed that the crucial variables affecting the activity, the selectivity, and the deactivation of the catalysts were their pore size/architecture and the amount of the acid sites. ZSM-5 (MFI, Si/Al = 15) outperformed the other zeolites, exhibiting higher selectivity in alkylation and substantially higher resistance to the deactivation.