Research on Hydrogenolysis of Glycerol to 1, 2-Propylene Glycol by Using Supported Raney-Cu/Al2O3

New supported Raney-Cu catalyst was prepared from pseudo-boehmite powder and copper aluminum alloy powder. It could be used in a continuous-flow fixed-bed reactor and it was also a good catalyst for hydrogenolysis of glycerol to propylene glycol after the two raw materials were processed by the following procedures: molding, drying, calcination, and leaching. XRD, H2-TPR, as well as SEM technique were employed to study the physicochemical properties of the catalysts, and the hydrogenolysis of glycerol to 1,2-propylene glycol (1,2-PDO) was used as a probe to evaluate the performance of supported skeletal copper catalysts. The test result indicated that CuAl2 was the main crystal phase of precursor after the dried strips were calcined at 850 °C in air. A part of CuAl2 was oxidized to α-Al2O3, which was the main contributor to the strength of Raney-Cu/Al2O3, while the remaining CuAl2 was converted to active skeletal copper after the leaching process. The effects of reaction temperature, hydrogen pressure, LHSV, hydrogen-oil ratio, glycerol concentration, and alkaline additives on the catalytic performance were studied in water or ethanol, respectively. Conversion of glycerol and selectivity of 1,2-PDO were 30.9% and 91.4% in water, or 99.0% and 73.6% in the ethanol system, respectively, when the reaction was performed at a temperature of 215 °C, a H2 pressure of 3 MPa, a LHSV of 1.0 h-1, a hydrogen-oil ratio of 500, and a glycerol concentration of 20%(ethyl alcohol solution).

New supported Raney-Cu catalyst was prepared from pseudo-boehmite powder and copper aluminum alloy powder.It could be used in a continuous-flow fixed-bed reactor and it was also a good catalyst for hydrogenolysis of glycerol to propylene glycol after the two raw materials were processed by the following procedures:molding,drying,calcination,and leaching.XRD,H2-TPR,as well as SEM technique were employed to study the physicochemical properties of the catalysts,and the hydrogenolysis of glycerol to 1,2-propylene glycol（1,2-PDO）was used as a probe to evaluate the performance of supported skeletal copper catalysts.The test result indicated that CuAl2 was the main crystal phase of precursor after the dried strips were calcined at 850 ℃ in air.A part of CuAl2 was oxidized to α-Al2 O3,which was the main contributor to the strength of Raney-Cu/Al2 O3, while the remaining CuAl2 was converted to active skeletal copper after the leaching process.The effects of reaction temperature,hydrogen pressure,LHSV,hydrogen-oil ratio,glycerol concentration,and alkaline additives on the catalytic performance were studied in water or ethanol,respectively.Conversion of glycerol and selectivity of 1,2-PDO were 30.9% and 91.4% in water,or 99.0% and 73.6% in the ethanol system,respectively,when the reaction was performed at a temperature of 215 ℃,a H2 pressure of 3 MPa,a LHSV of 1.0 h-1,a hydrogen-oil ratio of 500,and a glycerol concentration of 20%（ethyl alcohol solution）.