Tuning the mesoscopically structured ZSM-5 nanosheets for the alkylation between toluene and methanol

Mesoscopically structured ZSM-5 nanosheets were prepared as highly active catalysts for the alkylation between toluene with methanol. The results showed that the Bronsted acid sites of ZSM-5 nanosheets were mainly distributed on the external surface in aluminum-rich zeolites owing to the charge-balance between positive quaternary ammonium cation (N+) in Cph-10-6-6, Na+ ions and negative aluminosilicate species. In addition, it revealed that high alkalinity was easier to depolymerize the (sic)Si-O-Si(sic) species in Aluminum-rich synthesis gel, and the high alkalinity was required for silica-rich systems to dissolve silica species in order to finish the self-assemble process, leading to ZSM-5 nanosheets with high alkalinity presenting enhanced catalytic performance. Moreover, the optimized ZSM-5-50-2.5 was effective for the alkylation between toluene and methanol with toluene conversion of up to 50%, and it was stably operated for 48 h under the harsh conditions of WHSV = 32.5 h(-1) with a desired stability.