Effect of Impregnation Solvents in the Preparation of Ru/SiO2 Catalysts on the Partial Hydrogenation of Benzene

Abstract

Ru/SiO2 catalysts were prepared by impregnating RuCl3·nH2O into silica in a series of solvents which can coordinate to metal ions and activating in hydrogen. The effects of the im-pregnation solvents on the Ru/SiO2 catalyzed hydrogenation of benzene were investigated. In the catalysts activated in hydrogen without calcination, cyclohexene yields were in the range of 9 to 25 depending on the complexing ability of the preparation solvents. When the impregnation solvents had strong coordination ability, the catalysts showed low cyclohexene yields. But when the impregnation solvents had weak coordination ability, the catalysts showed high cyclohexene yields. For instance, 2-aminoethanol and ethanol gave the catalysts showing the highest and lowest cyclohexene yields respectively. When the catalysts were activated in hydrogen after cal-cination, all the catalysts showed almost the same cyclohexene yields in spite of the different kinds of impregnation solvents. The visible spectra of the catalyst preparation solutions and thermogravimetric analyses of non-calcined catalysts indicated that differences between the catalysts with and without calcination is due to inclusion of impregnation solvents in non-calcinated catalysts after activation.