Influence of reduction time of copper based catalysts: Cu/Al₂O₃ and CuCr₂O₄ on hydrogenolysis of glycerol

High activity of copper based catalysts for C-O bond hydro-dehydrogenation and their poor activity for C-C bond cleavage1 have prompted an attempt to apply such catalysts in the hydrogenolysis of glycerol to 1,2- and 1,3-propanediol. In the present study the influence of hydrogen reduction time of the Cu/Al₂O₃ and CuCr₂O₄ copper catalysts on glycerol conversion and selectivity of transformation to propanediols and by-products was studied. At first a general comparison was made between the commercial catalysts and those prepared by the co-precipitation method. As better results were obtained in the presence of catalysts prepared by co-precipitation, they were selected for further detailed studies of the influence of reduction time. For both prepared catalysts Cu/Al₂O₃ and CuCr₂O₄ the reduction time of 8 h was optimal. In the presence of Cu/Al₂O₃ catalyst the conversion of glycerol was 59.0%, selectivity of transformation to 1,2-propanediol 77.4% and selectivity to 1,3-propanediol 1.9%. In the presence of CuCr₂O₄ the glycerol conversion was 30.3% and selectivity to 1,2-propanediol 67.3%.