Homogeneous catalytic hydrogenation of the esters of bicarboxylic acids

Abstract Dimethyl oxalate may readily be hydrogenated in the presence of Ru(CO) 2 (CH 3 COO) 2 (PBu 3 ) 2 to methyl glycolate, which is subsequently reduced at a much slower rate to ethylene glycol. The reduction to ethylene glycol is favourably affected by a high hydrogen pressure and the pre-treatment of the catalytic system with a hydroxylated reactant such as methyl glycolate or ethylene glycol itself. The catalytic system under reaction conditions seems to evolve towards less reactive species. Under optimum conditions a 95% conversion of dimethyl oxalate to the corresponding glycol has been achieved.