ABSTRACT
S. Gobbles, N. Mahata, M. Hegedus, I. Borbath, and J. L. Margitfalvi Institute of Chemistry, Hungarian Academy of Sciences, Budapest, Hungary
ABSTRACT
Three series of catalysts with Ru-and Sn-loading ranging from 1.0 to 6.9 and 0 to 17.5 wt. %, respectively, were prepared by consecutive or co-impregnation varying the impregnation sequence with different precursor salts (RuCl3, Ru(acac)3, SnCl2,xH2O and Ci2H24O4Sn), metal loading and Sn:Ru atomic ratio. The calcined catalysts were characterized by Temperature Programmed Reduction (TPR). Coimpregnation of alumina with SnCl2xH2O and RuCl3 at 5 wt.% Ru loading and Sn:Ru atomic ratio of 2 resulted in the most active catalyst. Ethyl laurate was hydrogenolyzed to dodecanol and ethanol on the 5%Ru-11.6%Sn/Al2O3 catalyst at 250 °C and 10 MPa H2 pressure with 95 % conversion and 83 % selectivity. Correlation was found between the yield of dodecanol and the amount of hydrogen consumed for the reduction of tin species in the TPR experiment above 260 °C. Co-impregnation provides close interaction of ruthenium with tin, resulting in the formation of highly active "Snn+-Ru ensemble sites" to the maximum extent. The formation of a "metal ion-metal nanocluster active site ensemble" is required to activate the carbonyl group of the substrate.
