Preparations of Highly Dispersed Nickel and Cobalt Catalysts by Using Transparent Gel Membrane and Applications of the Catalysts to Hydrogenation Reactions

Abstract

Highly dispersed nickel and cobalt catalysts supported on active carbon or alumina have been prepared by a thermal decomposition of the precursor of a cellulose-hydrous metal oxide gel membrane or that of an alumina-metal nitrate gel membrane. The precursor of a gel membrane was obtained from a sol-gel process using ultra fine alumina sol derived from aluminum chloride or a finely porous cellulose gel membrane. The size of a catalyst particle is controlled by the dimensions of the gel network of a homogeneous precursor gel. The reaction properties of such a catalyst have been investigated in the hydrogenation of 1, 3- or 1, 5-cyclooctadienes. The selectivity for monoene and activity tends to increase with decreasing size of the catalyst particle (5-20 nm). The selectivity for monoene by the catalyst is higher than or close to that of the impregnated catalyst. However, the activity is generally lower than that of Raney catalyst. This may be attributable to the tendency of metal particle to be coated with support material. This preparation should produce well-dispersed metal particles supported on active carbon or alumina in one step. It can this simplify the fixation process of metal particles on supports which is usually employed in the preparation of the ultra fine catalyst particles.