The effect of metal–acid balance in Pt-loading dealuminated Y zeolite catalysts on the hydrogenation of benzene Original Research Article

The performances of various Pt-loading dealuminated Y zeolite catalysts for the hydrogenation of benzene were investigated in detail. The load of platinum was from 0.05% to 2% and the Si/Al ratio of the dealuminated Y zeolite was 17 or 2.6. It is found that the reaction condition and catalyst composition can influence the benzene conversion and the product selectivity substantially. Both the catalytic activity and the yield of cyclohexane increase drastically with the raise of Pt load on a given support at low Pt loads, but they increase very slowly when Pt loads are higher than 0.5%. At constant Pt load, the support with more Brønsted acid sites favors the production of methylcyclopentane and improves the overall hydrogenation activity. It is proposed that over noble metal/acid zeolite catalysts the hydrogenation reaction could take place on metal sites as well as on acid sites. The productions of cyclohexane and methylcyclopentane from benzene on acid sites are two competitive reactions through the same carbonium ions, such that cyclohexane and methylcyclopentane turn out to be primary reaction products.