Study On Glycerol Hydrogenolysis Over Supported Copper-Based Catalysts

In this paper, low-cost copper was used as the main active ingredient for the heterogeneous catalyst, copper-based catalysts were prepared by precipitation method and impregnation method, then applied to the catalytic hydrogenolysis reaction of glycerol. The activity and selectivity of copper-based catalysts were examined in the catalytic hydro geno lysis reaction of glycerol. The results show that copper-based catalysts prepared by precipitation method have smaller specific surface area, better loadings and stability, higher catalytic hydro geno lysis activity than those of copper-based catalysts prepared by impregnation method. The factors of forming were also discussed.CeO2modified CuO/SiO2catalysis was prepared by precipitation method. The catalytic activity of the catalysis for hydro geno lysis of glycerol on the continuous micro fixed bed reactor was evaluated. The effects of reaction temperature, pressure of H2, molar ratio of hydrogen and alcohol, concentration of glycerol and other conditions on hydro geno lysis of glycerol on continuous micro-fixed bed reactor were also considered. The results shows that the conversion rate of modified CuO-CeO2/SiO2catalyst for glycerol is100%and the selectivity for1,2-propylene glycol is as high as95%under the conditions of the reaction temperature at220℃, pressure of H2is0.5MPa, concentrations of glycerol is100%, molar ratio of hydrogen and alcohol at35:1, liquid hourly space velocity is0.025h-1.The hydro geno lysis mechanism of catalyst for glycerol was proposed by the analysis of the components of products. The prepared catalyst was characterized by means of XRD, BET, DSC/TGA, SEM, ICP-AES, the relationship among synthesis, structure and properties of catalyst was determined, it can provides a theoretical guidance for the preparation of the catalyst and mechanism of reaction.The effects of several additives on the reactive activity of copper-based catalyst for hydrogeno lysis of glycerol were also investigated, especially, the conversion rate of glycerol and the selectivity of1,2-propylene glycol were studied when CuO/SiO2, CuO-PTA/SiO2, CuO-CeO2-PTA/SiO2, CuO-CeO2/SiO2were used as catalysts, and the effects of reaction temperature, pressure, ratio of hydrogen and alcohol and the concentration of glycerol on the the conversion rate of glycerol and the selectivity of1,2-propylene glycol were discussed. It is advantageous to generate acetone alcohol by the dehydration of glycerol when the PTA was added into the CuO-PTA/SiO2catalyst. Under the conditions of reaction temperature at220℃, pressure of H2is0.5MPa, ratio of hydrogen and alcohol is35:1, the CuO-CeO2/SiO2exhibit better conversion rate of glycerol and the selectivity of1,2-propylene glycol as well as smaller particle size, better dispersion and greater specific surface area.