Selective hydrogenation of toluene over ruthenium catalysts prepared by the sol-gel method

A group of ruthenium supported catalysts (silica or silica-active charcoal supports) were prepared by the sol-gel method with the aim of obtaining high yields of methylcyclohexene in hydrogenation of toluene. The catalysts differed in composition and in conditions of reduction of their precursors. It was found that the hydrogenation could proceed as a consecutive reaction and that this pathway was accompanied by a parallel direct formation of methylcyclohexane from toluene. A positive role of water in a reaction mixture in view of an increased methylcyclohexene yield was also shown.