Hydroalkylation of Benzene and Methylbenzenes

A series of nickel catalysts supported on silica-alumina was prepared for hydroalkylation of aromatic hydrocarbons and effects of pretreatment of catalysts and reaction conditions on their catalytic activity were studied. The selectivity of cyclohexylbenzene which is obtained by hydroalkylation of benzene correlated to the surface acidity of silica-alumina support. The most suitable catalyst was nickel (3∼5wt%) supported on silica-alumina (alumina content: ca. 42wt%), and the results obtained with this simple catalyst were compared with those obtained with catalyst of nickel on a silica-alumina carrier containing both tungsten and fluorine reported by Slaugh et al.The molar ratio of cyclohexylmethylbenzenes to cyclohexylbenzene formed by the reaction of equimolar mixture of benzene and methylbenzenes increased with increase in the basicity of the methylbenzenes.