Study On The Catalytic Conversion Of Galactose And Glucose To Prepare 5-hydroxymethylfurfural

Today,global fossil fuels are facing the challenge of gradual depletion and increasing attention to energy and the environment.The Synthesis of Fine Chemicals and fuels in a sustainable and economic manner is one of the major challenges facing the world.Biomass has the characteristics of reproducibility,low pollution and wide distribution.The conversion of carbohydrates from inedible biomass into fine chemicals and fuels is of great significance to global sustainable development strategies.In recent years,5-hydroxymethylfurfural(5-HMF)has been paid more and more attention as an important chemical intermediate,which has been widely used in the synthesis of fine chemicals,fuels,pharmaceutical intermediates and polymer materials.The production of5-HMF from abundant biomass in nature is one of the most important tasks in the field of biomass resource utilization.Lignocellulose is the main component of biomass,including Lignin,hemicellulose and cellulose three parts.Recently,many advances have been made in the preparation of 5-HMF from hexose(For example Fructose and Glucose),and the related research has been extended to the utilization of cellulose.However,the conversion of hemicellulose to 5-HMF is still less reported.Hemicellulose is a polymer composed of several different types of monosaccharides.These monosaccharides are mainly composed of five-carbon sugar and six-carbon sugar,including xylose,Arabinose,glucose,galactose,mannose and so on.The study on the transformation of these monosaccharides can provide reference for the utilization of hemicellulose resources.The preparation of 5-HMF from Galactose and glucose was studied in this paper.The preparation of 5-HMF from galactose catalyzed by metal chloride was studied.The type of catalyst,water content of the system and the amount of the catalyst were investigated,the effects of substrate amount,reaction time and reaction temperature on the conversion of galactose to 5-HMF were studied.The mechanism of conversion and formation of 5-HMF was also discussed.The results showed that ZrCl₄exhibited better catalytic activity.In the mixed solvent of DMSO and water,the reaction conditions were 130°C,the reaction time was 90 min,the conversion of galactose and the yield of 5-HMF were 94%and25%,the related information of Reaction Mechanism was obtained through control experiment.In this paper,a series of Cr-supported silica-based catalysts were prepared by sol-gel method.The structure of the catalysts was analyzed by x-ray diffraction(XRD),scanning electron microscopy(SEM),electron spectroscopy(eds),infrared spectroscopy(ir)and X-ray fluorescence spectroscopy(XRF),the Catalytic Conversion of glucose to 5-HMF was studied by using this catalyst.The results show that the catalyst has good catalytic activity when Si/Cr=40.In order to improve the acidity of the catalytic system and promote the conversion of glucose,CrSiO-40 and Mordenite were used as co-catalysts for the reaction of Glucose at 150°C for 60 min in ionic liquid[BMIM]Cl,the conversion of glucose could reach 98%,the yield of 5-HMF can reach 58%,and the catalyst can be used continuously for five times without losing its catalytic.