LIQUID-PHASE HYDROGENATION OF BENZONITRILE OVER PT AND PT-SN CATALYSTS

Hydrogenation of benzonitrile has been studied over supported Pt and Pt-Sn catalysts. The effect of platinum particle size on the rate of Hydrogenation has been also investigated. Dibenzylamine is preferentially formed on all catalyst samples with a selectivity which is little influenced by the level of conversion, platinum particle size and Pt/Sn ratio. In the range of experimental conditions used, the rate of reaction does not depend on the platinum particle size and therefore the Hydrogenation of benzonitrile can be considered a structure-insensitive reaction. Addition of tin ions to platinum leads to an increase in the rate of reaction at lower tin content, whereas a decrease in rate is observed at the highest Sn/Pt ratios. It is suggested that the presence of tin ions enhances the reactivity of the CN group. © 1990.