Preparation of the hydrogenation catalysts with unusually high activity is accomplished by reacting the metal alkoxide with an organo-aluminum compound of the formula: wherein R is a hydrocarbon group of from 1 to 10 carbon atoms, and n is an integer from 0 to 3 (preferably from 0 to 2), inclusive, R may be an alkyl, aryl, alkaryl, aralkyl, or cycloaliphatic group.