Abstract
Studies on nickel/alumina catalysts, prepared by deposition of nickel chloride vapors on spherical alumina (3.5mm diameter) and by gas phase reduction of nickel chloride vapors, were undertaken to investigate the effects of the methods of preparation, including impregnation, on the catalytic properties. The rate of benzene hydrogenation per unit surface area of nickel particle (calculated from the nickel content and surface mean diameter of nickel) on the catalyst prepared by gas phase reduction was not so different from that prepared by impregnation; whereas the rate of hydrogenation observed on the catalyst prepared by vapor deposition was from 3 to 8 times greater than the catalyst prepared by impregnation. This seems to be caused by the characteristics of the nickel particles resulted from vapor deposition, i.e., deposition makes the surface uneven or brings about higher activity per unit surface area of nickel. Cyclohexene showed the following order of selectivity: vapor deposition>gas phase reduction> impregnation.
