Preparation Of Cu/ZIF-8 Derivative Catalyst And Catalytic Study Of Biomass Glycerol To Lactic Acid

How to realize the effective utilization of glycerol as a by-product of biodiesel has been a hot issue in industrial research in recent years.Among them,dehydroisomerization of glycerol is an important way to produce lactic acid.At present,the main method of preparing lactic acid from biomass glycerol in industry is fermentation,but it has some disadvantages such as low acid yield,difficult separation,long period and only intermittent production.Similarly,microbial enzymatic method,acetaldehyde hydrocyanic acid method,propene-N₂O₄method and other chemical synthesis methods also generally have problems such as high price, difficult purification,and harsh reaction conditions.Therefore,the use of catalytic synthesis method,the selection of appropriate metal active components and appropriate catalyst carrier,the preparation of supported nano-metal catalyst,biomass glycerol to prepare lactic acid reaction,has become the focus of research.At present,precious metal catalysts have been widely used in the preparation of lactic acid from biomass glycerol.However,the difficulty in obtaining raw materials and the high cost limit their further application in industry.In this paper,ZIFs supported nano-sized copper catalyst Cu/ZIF-8 with different loads was prepared by the synthesis reaction of copper nitrate,zinc nitrate and 2-methylimidazole at room temperature,and porous carbon material Cu/ZnO/C was prepared by high temperature calcination reduction,and these two materials were applied to glycerol to prepare lactic acid reaction.Characterization methods including XRD,XPS,SEM,TEM,BET,FT-IR,UV-Vis DRS,CO₂-TPD and TG were used to study and evaluate the morphology and properties of the catalyst.The results showed that the body-centred cubic lattice structure of ZIF-8 in the material was successfully synthesized.In addition,copper nanoparticles are evenly dispersed on the surface of the carrier and in the pore structure,which also provides sufficient alkaline active sites for the catalyst,which is conducive to the forward catalytic reaction.The conversion of glycerol and the yield of lactic acid can reach 97.6%and 84.2%respectively under the optimum reaction conditions and loading capacity.