Preparation Of Heteropoly Acid Ionic Liquid Catalyst And Its Catalytic Performance

With the development of society,the demand for all kinds of resources is increasing day by day.The reserves of traditional petroleum resources are limited,so it is urgent to find renewable resources to replace them.As a renewable resource with abundant reserves,biomass can be hydrolyzed into sugars（glucose,fructose,xylose,and etc.）that can be dehydrated to produce high value-added platform compounds.5-hydroxymethyl furfural（5-HMF）can be prepared by dehydration of fructose,and through series of chemical reactions,it can be further converted into valuable chemicals such as2,5-furandicarboxylic acid.In the process of converting fructose to 5-HMF,furfural and other by-products are also produced.Furfural can be hydrogenated to furfuryl alcohol.Furfural alcohol has a wider range of applications,such as production of synthetic resins and aerospace fuels.In this thesis,a variety of heteropoly acid ionic liquid catalysts are designed and prepared for the efficient preparation of 5-HMF by catalytic oxidation dehydration of fructose,and furfuryl alcohol by the catalytic hydrogenation of furfural.The structure of the catalyst are characterized and their catalytic performance are investigated.Firstly,triphenylphosphine,1,4-Butane sultone and heteropoly acids（phosphomolybdic acid,phosphotungstic acid and silicotungstic acid）are used as raw materials to design and synthesize three heteropoly acid ionic liquid catalysts:[TPHBS]₃PMo₁₂O₄₀,[TPHBS]₃PW₁₂O₄₀and[TPHBS]₄Si W₁₂O₄₀,for the preparation of5-HMF by catalytic oxidative dehydration of fructose.Their structures and surface morphologies are characterized by FT-IR,NMR,XRD,and SEM,the acidity of the catalysts is tested by UV-Vis,and the thermal stability is evaluated by TGA.The catalytic effect is investigated by HPLC,and it is found that[TPHBS]₃PW₁₂O₄₀shows the best catalytic effect on the dehydration of fructose to 5-HMF.The effects of types of solvents,reaction temperature and time,and the dosage of catalyst are studied to determine the optimum reaction conditions.The yield of 5-HMF can reach 97.31%with the following conditions:200 mg of fructose,12 ml of methanol,20 mg of[TPHBS]₃PW₁₂O₄₀,temperature of 90℃and reaction time of 90 min.However,the yield of 5-HMF decreases about 50%after the catalyst is reused for 5 times.Then,piperidine,1-methylimidazole,trimethylamine,1,4-Butane sultone and zirconium modified phosphotungstic acid are used as raw materials to design and synthesize three kinds of zirconium modified heteropoly acid ionic liquid catalysts:[Py BS]-Zr-PW,[MIBS]-Zr-PW and[TEABS]-Zr-PW,for the preparation of furfuryl alcohol by catalytic hydrogenation of fructose,a byproduct of the conversion of fructose to 5-HMF.Their structures and surface morphologies are characterized by FT-IR,NMR,XRD,XPS and SEM,and the acidity of the catalysts is tested by UV-Vis.The effect of cation on the catalytic effect is studied.It is found that[Py BS]-Zr-PW shows the best catalytic activity.The effects of types of solvents,reaction temperature and time,and the dosage of catalyst are studied to determine the optimum reaction conditions.The yield of furfuryl alcohol can reach 87.51%with the following conditions:1 mmol of furfural,12 ml of isopropanol,200mg of[Py BS]-Zr-PW,temperature of 120℃and reaction time of 80 min.The recycling performance of zirconium modified heteropoly acid ionic liquid catalyst is good.After five times of recycling,the yield of furfuryl alcohol is only decreased by～5.26%.