Conversion Of Cellulose To5-Hydroxylmethylfurfural In Ionic Liquid

With the develpoment of society and economy, resources were wanted everywhere. However, fossil resource such coal,petroleum and nature gas were depletion. Cellulose, the largest output biomass in nature, is drawing a lot of attention in recent years. As a product of cellulose degradation, HMF was considered to be one of the most potential platform chemicals which have several different functional groups.It is usually produced from fructose and glucose. If it could be produced from cellulose directly, the production cost will be reduced greatly. Ionic liquids were a rising kind of organic solvents in recent30years.They have many advantages such as little vapour pressure, programable, wide electrochemical windows, good thermostability and chemical stability, and good fire resistance.Since the good solubility of cellulose was found, the application of ionic liquids in cellulose regeneration, derivatization and degradation was researched widely. Due to its special structures among molecules and anhydrous environment, ionic liquids have many advantages in degradation of cellulose to HMF. This paper presents the works on degradation of cellulose to HMF catalyzed by bifunctional ionic liquids and metal chlorides in [BMIM]C1.A new kind of bifunctional ionic liquid catalysts was synthesized to degrade microcrystalline cellulose in [BMIM]C1at atmospheric pressure. The effects of reaction temperature, amount of catalysts, reaction time, ionic liquid purity and cellulose concentration on the catalytic performance were investigated. At low temperature cellulose can be degraded with being heated in [BMIM]C1by oil bath. Among the as-synthesized catalysts, Cr([PSMIM]HSO4)3exhibited the best performance. Compared with [PSMIM]HSO4, HMF yield was improved a lot and HMF was stable in Cr([PSMIM]HSO4)3. The HMF yield of53%and TRS yield of94%can be achieved at120℃in [BMIM]C1for5h over0.05g Cr([PSMIM]HSO4)3/2.0g [BMIM]C1with95%cellulose conversion. The mechanism of this reaction was suggested and the recycle of this catalysis system was tested.Conversion of cellulose to HMF (5-Hydroxymethylfurfural) in one step by metal chlorides (CrCl3, CuCl2, WC16, SnCl4) in [BMIM]C1has also been researched. The effect of temperature, reaction time, catalysts amount, and the purity of [BMIM]C1on the performance have been detailed discussed. More than63%yield of HMF and80%yield of TRS (total reducing sugar) were obtained with CrCl3in [BMIM]C1at120℃and atmosphere pressure. Filter paper and cotton were also tried to be degraded to HMF, but only moderate yield of HMF was obtained (40%for filter paper and12%for cotton). The recycle of this system and mechanism of this reaction are also discussed.Degradation of cellulose in [BMIM]C1catalyzed by WC16has been researched in this paper. The experiments results show that more than80%yield of total reducing sugars were produced at atmosphere pressure and70℃, which is much lower than that ever reported. The influence factors including temperature, time and catalyst amount have been discussed and a mechanism of this reaction was suggested. The good ability of degradation of cellulose at low temperature was ascribed to its good ability of combining with O in cellulose.