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