Hydrogenation of C=C and C=O Groups on Ruthenium-Tin Catalysts

The effect of addition of tin on the catalytic activity of Ru/C catalysts has been investigated in the liquid phase hydrogenation of β-methylstyrene and hydrocinnamaldehyde. On increasing the Sn content, the amount of CO chemisorbed decreases, indicating a decrease in the number of Ru surface atoms. In the hydrogenation of β-methylstyrene the specific activity of Ru (calculated per Ru surface atom) remains constant regardless of the Sn/Ru ratio. An increase of specific activity is however observed in the hydrogenation of hydrocinnamaldehyde. It is suggested that tin, present mainly as Sn ions, enhances the reactivity of the C=O group.