The catalytic dehydrogenation of cyclohexane and methylcyclohexane over nickel loaded Y zeolites

The dehydrogenation of cyclohexane to benzene and of methylcyclohexane to toluene was investigated over a range of nickel Y zeolites, varying the nickel content and the nature of the alkali metal co-cation (Li⁺, Na⁺, K⁺, Rb⁺ or Cs⁺). The overall reaction is viewed as occuring via a series of consecutive dehydrogenation steps. Catalytic activity is correlated with the reaction time, the reaction temperature, the level of Ni²⁺ exchange and the effects of pyridine adsorption. The level of dehydrogenation is strongly dependent on the mass of supported nickel metal and the surface Bronsted acidity. Catalyst deactivation results from the deposition of coke on the catalyst surface which is promoted with increasing zeolite acidity.