Synthesis And Catalytic Acitivy Of Solid Polyoxometalates Catalysts

Biomass is an abundant and the only sustainable carbon resource, and biomassenergy must be new type energy which will replace the diminishing fossil-basedresources. Particularly, one of the biomass resources is sugar, which can bedehydrated into5-hydroxymethylfurfural (HMF) in acidic conditions. HMF is aversatile intermediate, which can be used to produce many useful furan derivatives. Inthe paper, the dehydration of fructose and glucose into HMF by polyoxometalates ascatalyst are explored in DMSO and H2O/1-butanol reaction system, and differentreaction conditions are investigated to obtain ideal conversion and yield.1.(C16TA)H3CrPW11O39(OH2)was prepared and were determined by IR，IRspectrum of adsorbed pyridine, UV-vis, XRD, ICP-AES,31P-MAS NMR and so on.The dehydration of fructose into HMF by (C16TA)H3CrPW11O39(OH2) as catalyst wasinvestigated. The catalytic activity was evaluated in terms of reaction time,temperature, amount of catalyst, solvent and addition salt, different catalysts andreusability of the catalyst. The results were shown as following: under reactionconditions as0.01mmol of catalyst,30wt%of concentration of fructose, volumeratio of1:3, at130C for90min,93.9%conversion and76.1%yield were obtained.After the reaction, the catalyst can be separated by centrifuge.2.(C16TA)H4TiPW11O40was prepared and were determined by IR, IR spectrumof adsorbed pyridine, UV-vis, XRD, ICP-AES,31P-MAS NMR, and so on. Thedehydration of fructose into HMF by (C16TA)H4TiPW11O40as catalyst wasinvestigated. The catalytic activity was evaluated in terms of reaction time,temperature, amount of catalyst and solvent and addition salt, different catalysts,different length of carbon chain, and reusability of the catalyst. The results wereshown as following: under reaction conditions as0.01mmol of catalyst,30wt%ofconcentration of fructose, volume ratio of1:3, at130C for90min,93.9%conversionand76.1%yield were obtained. After the reaction, the catalyst can be separated bycentrifuge.3. The dehydration of fructose into HMF by ionic crystalCs2[Cr3O(OOCC2H5)6(H2O)3]2[α-SiW12O40] as catalyst was investigated. Theproperties of ionic crystal were determined by IR, IR spectrum of adsorbed pyridine,ICP-AES, and the acidic content of Br nsted was evaluated by titration. The catalytic activity was evaluated in terms of reaction time, temperature, amount of catalyst andsolvent, different catalysts and reusability of the catalyst. The results were shown asfollowing: under reaction conditions as0.03g of catalyst,9.1mL of DMSO,0.3g offructose, at130C for90min,100%conversion and85.9%yield were obtained. Afterthe reaction, the catalyst can be separated by centrifuge and recycled for five times.