CATALYTIC AND STRUCTURAL-PROPERTIES OF RUTHENIUM BIMETALLIC CATALYSTS - EFFECTS OF PRETREATMENT ON THE BEHAVIOR OF VARIOUS RU/AL2O3 CATALYSTS IN ALKANE HYDROGENOLYSIS

Very highly dispersed 1% Ru/Al2O3 prepared from Ru(acac)(3), after high-temperature reduction, catalyses the hydrogenolysis of n-butane with a high and almost temperature-independent selectivity to ethane. Catalysts having higher Ru contents (2.5 and 4%) are less well dispersed, but show higher turnover frequencies for this reaction, and selectivities which change with temperature, with methane the major product throughout. Oxidation and low-temperature reduction of these catalysts causes loss of metal area, and much enhanced turnover frequencies: product selectivity behaviour is then in each case that characteristic of large metal particles. A final high-temperature reduction leads to lower turnover frequencies, with little change in product selectivity. Results are also reported for catalysts prepared from RuCl3 and from Ru(NO) (NO3)(3), and for Ru powder: propane hydrogenolysis has also been examined as an adjunct to this study.