Effect of pre-treatment conditions on the performance of sulfided Ni–Mo/γ-Al 2O 3 catalysts for hydrogenation of linear aldehydes

Abstract

Effect of catalyst pre-treatment conditions on activity and selectivity of sulfided Ni–Mo/γ-Al 2O 3 catalysts in aldehyde hydrogenation reactions was studied. It appears that both of the sulfidation temperature and the post-sulfidation degassing temperatures can be effectively used to manipulate the surface density of anion vacancy sites and the hydroxyl and sulfhydryl sites over the sulfided Ni–Mo/γ-Al 2O 3 catalysts. Any changes in the surface density of these sites, in turn, can have significant effect on the activity and product distribution achieved over these catalysts in hydrogenation of linear aldehydes, hexanal and propanal. As established previously, NO and CO 2 can be used to probe the sites that promote the alcohol and heavy product formation reactions, respectively. The results obtained from XRD, XPS, DRIFTS, TPD and volumetric chemisorption measurements provide complementary information in establishing the correlations between the active sites and reaction performance.