A STUDY ON THE SELECTIVITY IN ACROLEIN HYDROGENATION ON PLATINUM CATALYSTS - A MODEL FOR HYDROGENATION OF ALPHA,BETA-UNSATURATED ALDEHYDES

Hydrogenation of acrolein, as a model molecule representing the alpha, beta-unsaturated aldehydes, has been studied with SiO2- and Al2O3-supp orted Pt and Cu catalysts. These catalysts were used to study the effe cts of various surface modifications. In addition to sulfurization by thiophene, the Pt/SiO2 catalysts were modified by acetylene, by inacti ve metal (Sn, Cu) admixture, and by gas modifiers (CO). Furthermore, t he effect of modification of the surface by the reaction mixture in th e initial stages of the reaction was followed. It appeared that the se lectivity in the hydrogenation of the alpha,beta-unsaturated aldehydes is influenced mainly by the presence of sites on the catalysts, which activate the aldehydic oxygen and allow an easy supply of hydrogen at oms. Effect of the ensemble size is much less important. Sulfurization as performed in this paper causes only a marginal effect on selectivi ty. Small selectivity effects can be also caused by gas modifiers like carbon monoxide. (C) 1995 Academic Press, Inc.