Construction Of Hydrosilane Transfer Hydrogenation System And Study On High Value Conversion Of Biomass Catalyzed By Hydrosilane

With the rapid development of modern society,people’s demand for fuel and chemicals is increasing day by day.Hydrogenation products and derivatives of biomass are valuable platform molecules which are widely used in the development of energy and fine chemicals.For example,furfural,furfuryl alcohol,ethyl levulinate and γ-valerolactone(GVL)are high value-added compounds formed by wood fibers after dehydration and hydrogenation,which are widely used in the chemical industry.Using hydrosilane as a hydrogen donor to construct highly selective hydrogenated biomass platform molecules in a mild system is of great significance for the development and utilization of biomass.In this paper,hydrosilane catalytic system is used to convert furfural into furfuryl alcohol and ethyl levulinate into GVL.The main work is as follows:(1)A room temperature highly selective hydrogenation system was constructed by using polymethylhydrosiloxane,an industrial by-product of silicon,as a hydrogen donor,and potassium fluoride,a commercial alkali metal salt as a catalyst.Single factor optimization was carried out for the reaction parameters such as the type of solvent,the amount of catalyst.Experiment the optimum reaction condition is obtained: 0.5 tendency for furfural,catalyst for 15 mg,100 mg dosage of hydrogen donor,2 mL of N,N-dimethylformamide,the reaction temperature is 25 °C,the reaction time of 0.5 h,furfuryl alcohol is the most high yield rate was 97%.(2)Based on the success of the room-temperature catalytic furfural experiment,this part further hydrogenated the biomaterial platform molecules at room temperature and tried to convert the platform molecules at room temperature to generate GVL.A commercially available catalyst for synthesis has been selected: tetra-n-butyl ammonium fluoride for the activation of polymethylhydrosiloxane.Through conditional screening,under the conditions of 2 mL ethyl acetate as solvent,5 mg catalyst dosage and 100 mg hydrogen donor dosage,the ethyl lepropionate could be completely transformed at room temperature and 0.5 h,and the yield of GVL was 85%.In the mechanism exploration part,based on literature research and experimental design,the reaction mechanism is described in the form of mechanism diagram.In addition,the system can also be used to convert furfural into furfuryl alcohol,the yield of furfuryl alcohol can reach 93%.(3)In this part,the chiral catalytic system with hydrosilane as hydrogen donor was discussed.The chiral catalysts were prepared in the form of metal-organic ligands.The reaction conditions(solvent,amount of hydrosilane,etc.)were discussed.In 15 mg Fe-R-BINAP catalyst,2.5 mg sodium tert-butyl alcohol additives used,2 mL tetrahydrofuran as solvent,25 °C,1 h can be achieved under the condition of the substrate: transformation of levulinic acid ethyl ester completely,gamma e lactone yield can reach 80%,the product of the ee value of 2%.