Conversion Of Glucose Into HMF Catalyzed With Molecular Sieves Modified By Metal Ions

With the continuous consumption of the fossil resource and more and more serious environmental issues, exploring and utilizing the renewable resource has received much attention by people. Biomass can be used as an effective substitute for fuel and many chemical products because of their abundance. Sugars, such as the fructose and glucose, can be used to produce high valued chemicals. So far, many works have been focused on converting hexose into HMF. As the cell unit of cellulose, glucose has more potential application prospect than other sugars because its price is very low.So far there are different catalytic systems used in the conversion of glucose, such as sulfuric acid, mixture of ion liquid and CrCl2, titanium dioxide, SO42-/ZrO2. The major problems for these systems include serious pollution, difficulties in separating and recovering the catalyst, low yield of HMF, complexity in reaction process, rigorous reaction conditions. The mixture of ion liquid and CrCl2 was applied into the conversion of glucose by Zhang and a high yield of HMF was achieved. But after the reaction the catalyst was impossible to be separated with others and serious pollution could be caused because of the Cr2.Based on the current problems in the conversion of glucose, we tried to apply the molecular sieves modified with Cr into the reaction hoping to recover the catalyst after reaction and reduce the pollution for the environment. In the system of [EMIM]Br, catalytic conversion of glucose into HMF using molecular sieves modified by different metal ions and with different framework modified by CrCl3 was investigated. Cr-Beta was found to be most effective for the catalytic reaction. The effects of different ion liquids, preparation method of catalysts, recycle of the system, reaction temperature, time and catalyst amount on the yield of HMF were also researched. A 35%yield of HMF was obtained when the reaction was catalyzed using H-Beta molecular sieve modified by CrCl3 with mass ratio of 50:5:1 (ionic liquid: reactant:catalyst) at 130℃for 60 min.