The Studies On Catalytic Dehydration Of Monosaccharide To5-hydroxymethylfurfural

In this thesis the dehydration of monosaccharide to5-hydroxymethylfurfural(5-HMF)catalyzed by the homogeneous catalyst and heterogeneous catalysts was studied, the mainresearch contents are as follows:NH4Br as homogeneous catalyst was evaluated for the dehydration of fructose to5-HMF.The effects of the category of co-catalyst, reaction temperature, reaction time, catalyst dosageand solvent type were investigated in detail. As a result, it was found that fructose could beefficiently converted to5-HMF using a combination of environmentally friendly NH4Br andLiBr as the catalytic system.5-HMF yield of74.5%could be attained at100℃for1h usingDMSO as solvent with fructose weight of1g and catalyst dosage of10mol%(based onfructose).Solid acid catalysts TPA/ZrO2and WO3/ZrO2were prepared by impregnation methodand evaluated for the dehydration of fructose to5-HMF. The effects of preparation conditionsincluding calcination temperature, active component loading and the reaction conditionsincluding the amount of catalyst, reaction time, reaction temperature, the amount of fructose, wereinvestigated in detail. The methods of BET, XRD, FT-IR and TG-DTG were employed tocharacterize TPA/ZrO2solid catalysts.The BET, XRD, FT-IR and TG-DTG characterized results showed that TPA was highlydispersed on the surface of the carrier enlarging the surface area of the catalyst, stronginteraction was occurred between TPA and the carrier, while retain the Keggin structure ofTPA.The experimental results showed that, for TPA/ZrO2solid acid catalysts, the appreciateconditions were: loading amount of20wt.%TPA, fructose quality of1g, catalyst dosage of20wt.%(based on fructose), reaction time of1.5h, reaction temperature of120℃, and5-HMF yield could attained73.3%under the above conditions. When dehydration of fructoseto5-HMF over WO3/ZrO2was performed, the catalyst with30wt.%WO3loading andcalcined at800℃, exhibited the best catalytic activity.5-HMF yield of64.5%could beattained at120℃for2h using DMSO as solvent with fructose weight of1g and catalystdosage of20wt.%(based on fructose).Solid catalyst SO42-/ZrO2-Al2O3was prepared and evaluated for the dehydration ofglucose to5-HMF. The effects of Zr/Al mole ratio, reaction time, reaction temperature and catalyst dosage were investigated in detail. An optimized glucose conversion of97.8%and5-HMF yield of40.2%were obtained within4h at130℃over SO42-/ZrO2-Al2O3(Zr/Al moleratio of1:1) with fructose weight of1g and catalyst dosage of20wt.%(based on fructose).