Study On Cooper Based Catalytic System And Green Processfor Syntheses Of Methanol And Ethylene Glycol Via Hydrogenation Of Ehtylene Carbonate Derived From Carbon Dioxide

Synthesis of methanol(MeOH)and ethylene glycol(EG)via hydrogenation of ethylene carbonate(EC)has been widely studied,due to its environmental friendliness,Mild reaction conditions and high atomic utilization.Although some reported copper-based catalysts for hydrogenation of EC showed good catalytic activities,the stability of catalytic activity and the catalytic mechanism are still unknown.Therefore,the copper catalytic system and process route are systematically studied in this paper,the main research contents and conclusions are as follows:1.Graphite oxide modified Cu-C@SiO2 catalyst was prepared by ammonia evaporation method using Cu-BTC as the precursor,and used in the hydrogenation of EC.TEM?H2-TPR?XRD?N2 stripping absorption and XPS characterization showed that the average Cu particle size was 2.9 nm,and copper particles were covered by graphite oxide which was in favor of the dispersion of Cu particle,as well as the surface area of catalyst.The performances of the Cu-C@SiO2 catalyst revealed that under the condition of 5 MPa,180?,4 h,the EC conversion could reach to 80.0%,with methanol and EG selectivity achieved to 70.8%and 92.2%,respectively.The fixed bed experiment showed that under the optimal conditions of 3 MPa,180?,H2/EC molar ratio 150 and LHSV 0.6 h-1,99.9%EC conversion could be attained,with methanol and EG selectivity reached to 83.7%and 98.3%,respectively.2.Long-period experiment of Cu-C@SiO2-R catalyst and DFT calculation were carried out.The experiment result indicated that under the condition of 180?,3.0 MPa,H2/EC molar ratio 150 and LHSV 0.6 h-1,the conversion of EC,selectivity of methanol and EG remained at 80.0%,70.8%and 92.2%,respectively in 264 hours,with the catalytic activity of 0.63 gEcgcat-1h-1.N2 stripping absorption?ICP-AES?TEM?XPS and XAES characterization results showed that graphite oxide slowed down the loss of copper components as well as the coking of copper particles,stabilized the Cu+/(Cu0+Cu+)molar ratio.DFT calculation indicated that Cu0 adsorbed and dissociated H2,while Cu+adsorbed and dissociated EC.It also indicated that the presence of graphite oxide could reduce the adsorption and dissociation energies.In the Cu-C@SiO2 structure,the reaction energy barrier was significantly reduced with graphite oxide and copper species coexisted,making the reaction easier to be carried out.3.The technological route to produce methanol and EG was developed from CO2,ethylene oxide and H2.The process was simulated and optimized using Aspen,to form the conceptual design of the production unit with an annual output of 100000 tons of EG and 44000 tons of methanol.The feasibility analysis indicated that the process is technically feasible,and the economic benefit analysis indicated that a profit of 735 yuan could be generated from each ton of EG and 0.44 tons of methanol.