LIQUID-PHASE HYDROGENATIONS OVER PLATINUM TIN CATALYSTS

Hydrocinnamaldehyde and phenylacetylene have been hydrogenated over Pt and Pt-Sn catalysts. the Pt-Sn system has been studied as a function of the Pt/Sn ratio. In the hydrogenation of the C EQUVLNT C triple bond, addition in tin to platinum causes a sharp decrease in the rate of reaction. In the hydrogenation of the C equals O group, an increase is instead observed at lower tin contents with a subsequent decrease at the higher Sn/Pt ratios. These results are discussed in terms of: (a) an interaction between tin and platinum which deactivates the active metal sites and (b) an interaction between hydrocinnamaldehyde and tin ions which enhances the reactivity of the C equals O group.