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 hig h-temperature reduction, catalyses the hydrogenolysis of n-butane with a high and almost temperature-independent selectivity to ethane. Cata lysts having higher Ru contents (2.5 and 4%) are less well dispersed, but show higher turnover frequencies for this reaction, and selectivit ies which change with temperature, with methane the major product thro ughout. Oxidation and low-temperature reduction of these catalysts cau ses loss of metal area, and much enhanced turnover frequencies: produc t selectivity behaviour is then in each case that characteristic of la rge metal particles. A final high-temperature reduction leads to lower turnover frequencies, with little change in product selectivity. Resu lts are also reported for catalysts prepared from RuCl3 and from Ru(NO )(NO3)(3), and for Ru powder: propane hydrogenolysis has also been exa mined as an adjunct to this study.