Catalytic Activity Of Acid-base Bifunctional Polyoxometalates In Monosaccharide Transformation

Due to the increasing depletion of fossil resources, the use of research resources for chemicals is an important renewable smelting technology research. Polyoxometalate(POMs) have high catalytic activity in biomass conversion. Because POMs is a strong Br?nsted acid catalyst, it has poor reactivity to sugar conversion. Design more active sites of POMs catalytic system to meet the needs of different glycosylation transformation have important academic and practical value. We use heteropolyacid to synthesis of acid-base bifunctional catalysts. We use glucose and fructose to dehydration to 5-HMF as a model reaction to evaluate the catalytic properties. The main work is as follows:1.(C6H15O2N2)3-xHxPW12O40 was prepared and determined by IR, XRD, 31P-MAS NMR and so on. Use(C6H15O2N2)2HPW12O40 as catalyst make the highest reactive. The catalytic activity was evaluated in terms of temperature, reaction time, amount of catalyst and different catalysts. The results were shown as following: Ch Cl and glucose weight ratio is 6/4, 130 oC for 3min, 0.016 mmol of catalyst, 64.9% conversion and 19.7% yield were obtained. In Ch Cl-H2O/MIBK reaction system, when weight ratio is 2-2/5, 160 oC for 4h, 73.3% conversion and 61.0% yield were obtained.In fructose dehydration reaction, Use Ch Cl as solvent, 110 oC for 1min, 93.3% conversion and 92.3% yield were obtained. In addition, Ly2 HPW is a kind of heterogeneous catalysts, can be recycled and reused.2. We synthesized different loads of hydroxyapatite/H3PW12O40( HAP/HPW) acid-base bifunctional composite materials. And determined by IR, XRD, 31P-MAS NMR acid-base property and so on. When using HPW loads of 28.59% HAP/HPW as catalyst reached the highest reaction efficiency. The catalytic activity was evaluated in terms of reaction time, temperature and so on. In glucose dehydration reaction, Ch Cl and glucose weight ratio is 6/4, 130 oC for 10 min, 0.031 mmol of catalyst, 62.7% conversion and 34.9% yield were obtained. In Ch Cl-H2O/MIBK reaction system, when Ch Cl-H2O/MIBK weight ratio is 2-2/5, 150 oC for 3h, 66.9% conversion and 59.2% yield were obtained.In the study of fructose dehydration reaction, Use Ch Cl as solvent, 110 oC for 5min, 92.9% conversion and 86.4% yield were obtained. In addition, HAP/HPW composite material is a kind of heterogeneous catalysts, can be recycled and reused.