Alkylation of benzene with methanol over hierarchical porous ZSM-5: synergy effects of hydrogen atmosphere and zinc modification

The competitive reaction of methanol to olefins is difficult to be suppressed in benzene alkylation with methanol over hierarchical porous ZSM-5. The influence of ZnO content and different atmospheres on the catalytic performance of hierarchical porous ZSM-5 catalyst was investigated. The results indicated that the introduction of ZnO could form the Lewis acid sites of zinc species (ZnOH+) at the expense of the Bronsted acid sites, and the reduction of strong Bronsted acid would help to suppress the side reaction of methanol to olefins. However, the presence of ZnOH+ could catalyze the dehydrogenation reaction of light hydrocarbons to olefins which would result in the formation of coke under the nitrogen atmosphere, while the hydrogen atmosphere could inhibit the dehydrogenation ability of ZnOH+.