THE HYDROGENATION OF BENZENE OVER NICKEL-SUPPORTED Y-ZEOLITES .2. A MECHANISTIC APPROACH

From a combination of kinetics, adsorption data, and the isolation and identification of reactive and unreactive intermediates, a detailed mechanism for the hydrogenation of benzene over zeolite-supported nickel is presented. Cyclohexane was identified as the major product with methylcyclopentane, a secondary product resulting from catalysis over the more acidic samples. Cyclohexene was isolated as a reactive intermediate that underwent a secondary catalysis involving both metal and acid sites to yield cyclohexylbenzene as the principal coke product. The partial hydrogenation of benzene to cyclohexene was found to be the rate-determining step. A model is proposed that best fits the experimental data.