Conversion Of Glucose To Methyl Levulinate Over Bi-functional Solid Acid Catalyst

With the consumption of fossil resources and the increasing of environmental problems related to using fossil resources, looking for a new resource to replace of fossil resources has became urgent. Renewable biomass is an ideal choice to replace fossil resources. A variety of chemicals can be synthesized from biomass. Levulinate esters are an important kind of organic compounds. Alcoholysis has become the main method for preparation of levulinate esters from biomass. Zeolites are a kind of porous solid materials with high specific surface, which shows good potential application in the catalytic conversion of glucose. This thesis mainly studied conversion of glucose to methyl levulinate（MLE） with high selectivity over zeolites through modifing the acidity and pore structure of catalyst.In this thesis, we first studied the catalytic activity of the hierarchical HUSY zeolites in rection of conversion of glucose to MLE. Hierarchical HUSY zeolites were prepared by treatment HUSY parent with different concentration of nitric acid to modify the mesopore volume of zeolites. The obtained hierarchical HUSY zeolites were characterized by XRD, FTIR, XRF, N2 physisorption and NH3-TPD. The results indicated that low concentration of nitric acid mainly removed the extraframework aluminum species of HUSY zeolites with the increase of mesoporosity and resulted in a slight decrease of acidity. Both extraframework and framework Al species were removed under high concentration of nitric acid, associating with the obvious decrease of acidity. The experiment results showed that HUSY-0.2, which was treated by 0.2 M HNO3, showed best catalytic activity with 54% yield of MLE at 180 oC for 20 h. The catalyst can be recycled for five times without obvious decrease of catalytic activity.The mixture of solid Lewis acids and Br?nsted acids were used as catalyst in the conversion of glucose to MLE. Sn-Beta combined with SO₄^2-/Zr O2 catalysts gave the best catalytic activity. The preparation conditions of SO₄^2-/Zr O2 catalysts were optimized, and SO₄^2-/Zr O2 catalyst showed best catalytic activity at 475 oC of calcination temperature, 1 M of sulfuric acid for dipping. 62% yield of MLE was obtained at 170 oC for 24 h when the mole ratio Lewis and Br?nsted is 1:9. The catalyst can be recycled for five times without obvious decrease of catalytic activity. Finally, we deduced a plausible pathway for conversion of glucose to MLE through the analysis of the products distribution with the change of reaction time.