PECULIARITY OF THE CATALYTIC ACTION OF NICKEL IN ZEOLITES OF TYPE-Y IN HYDROGENATION REACTIONS

The metal specific catalytic activity (Kspec) in hydrogenation of a series of unsaturated hydrocarbons: n-hexene-1, cyclohexene, the olefin bond in styrene, and 4-phenylbutene-1, as well as the aromatic ring in benzene, has been determined for a number of nickel-zeolite catalysts, nickel on silica and nickel black, with the surface of metallic nickel being varied from 4 to 690 m2/gNi. It has been shown that Kspec for nickel in zeolites toward the hydrogenation of a simple olefin bond does not depend on its dispersion and only slightly differs from that for the catalysts of comparison. A decrease in oxygen specific chemisorption and specific activity in hydrogenation of the aromatic ring was observed with increasing nickel dispersion in zeolites. The latter fact was related to the specificity of atomic states in nickel clusters located in zeolite cavities. © 1979.