Work

Highly para-selective alkylation of toluene by methyl mercaptan over silylated ZSM-5 zeolite

Year: 2024

Type: article

Abstract: Friedel-Crafts alkylation of toluene with methyl mercaptan has been investigated in the presence of H-ZSM-5 and SiO2/H-ZSM-5 catalysts. The silica layer has been deposited on H-ZSM-5 zeolite by impregnation with tetraethyl orthosilicate. The passivation with silica of the external surface of H-ZSM-5 zeolite has been confirmed by FT-IR spectroscopy and mesitylene isomerization, used as a model reaction. All catalysts exhibited notable behavior in the alkylation of toluene to xylenes. Efficiencies higher than 98% in alkylation for both toluene and methyl mercaptan were obtained at 375 °C. In terms of para-selectivity, outstanding performance was revealed by the silylated zeolites. Thus, over 12% SiO2/H-ZSM-5, at 375 °C and WHSV = 9.4 gtoluene+CH3SH gcat-1 h-1, the para-xylene selectivity was close to 100 %. The experimental apparent activation energy for the toluene alkylation with methyl mercaptan catalyzed by H-ZSM-5 was 80 kJ mol-1.

Source: Journal of Catalysis

DOI: 10.1016/j.jcat.2024.115828

Authors: Abdelilah Bayout, Claudia Cammarano, Izabel Medeiros Costa, Gleb Veryasov, Alexander Sachse, Vasile Hulea