A comparative study of Ir/Ga2O3, Pt/Ga2O3, and Ru/Ga2O3 catalysts in selective hydrogenation of crotonaldehyde

Catalytic performance of gallia-supported iridium catalysts in the reaction of selective hydrogenation of crotonaldehyde in the gas phase was studied and compared to that of platinum and ruthenium catalysts. The best catalytic properties in terms of the selectivity to crotyl alcohol are shown by 5 wt % Pt/α-Ga2O3 and 5 wt % Ir/α-Ga2O3 catalysts prepared from nonchlorine precursors: Pt(acac)2 and Ir(acac)3, but for the 5 wt % Pt/α-Ga2O3 a very high selectivity of 75% at the high conversion (ca. 60%) is observed. A high selectivity of galia-supported iridium and platinum catalysts was explained by the surface reducibility of gallium oxide leading to covering (decoration) of platinum and iridium by gallium suboxides and the promoting effect of gallium.