Tblw. Marinelli et V. Ponec, A STUDY ON THE SELECTIVITY IN ACROLEIN HYDROGENATION ON PLATINUM CATALYSTS - A MODEL FOR HYDROGENATION OF ALPHA,BETA-UNSATURATED ALDEHYDES, Journal of catalysis, 156(1), 1995, pp. 51-59
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.