Hydrogenolysis of glycerol to propylene glycol over Cu/oxide catalysts: influence of the support and reaction conditions

The syntheses, physicochemical properties and catalytic activity of Cu-containing catalysts in the hydrogenolysis of glycerol are reported in the present paper. The investigated catalysts contained various amounts of Cu deposited by wet impregnation over two oxide supports: Al2O3 and TiO2. The catalysts were characterized by the following techniques: XRD, H-2-TPR, BET/BJH and N2O adsorption. The catalytic activity of the prepared catalysts was studied in the selective hydrogenolysis of glycerol to 1,2-propanediol in order to understand the role of the support as well as to select the most active and selective catalyst. The influence of the following parameters was carefully studied: pre-reduction temperature, hydrogen pressure during pre-reduction and hydrogenolysis and reaction time. In addition, the influence of tungstophosphoric acid and sodium hydroxide additives was also studied. The best catalytic systems were identified in terms of glycerol conversion and 1,2-propanediol selectivity.