Dehydrogenation of cyclohexane and cyclohexene over supported nickel and platinum catalysts

The activities of two nickel catalysts prepared in our laboratory and of a commercial platinum catalyst were compared for benzene formation by dehydrogenation of cyclohexane and cyclohexene. A 15% nickel on alumina catalyst compares favourably with the commercial platinum catalyst at 300 °C; at lower as well as higher temperatures in the range 200–340 °C, the platinum catalyst is more effective. A 20% nickel catalyst compares unfavourably at all temperatures in the range studied. Results indicate that the orientation of adsorbed benzene depends on the dispersion of metal in the nickel catalyst and also on the temperature. During dehydrogenation of cyclohexene a small fraction was disproportionating, the extent of which was found to depend on the catalyst and the temperature.