Synthesis Of5-hydroxymethylfurfural Over Ionic Liquid Catalysts

5-Hydroxymethylfurfural(HMF) is a new type of platform compound. Becausethere was an aldehyde and a hydroxymethyl existed in its molecular, HMF can betransformed into hundreds of high value-added products via hydrogenation,esterification, alkylation, halogenation reactions which are widely used in medicine,resins plastics and diesel fuel additives. The preparation of HMF from glucose andsucrose was studied by conventional acid and acidic ionic liquid as catalysts. Theeffects of kinds of solvent and catalyst, the amount of solvent and catalyst, reactiontemperature, reaction time on the yield of HMF were examined.The preparation of HMF from glucose and sucrose was studied by conventionalacids as catalysts.The results showed that the composite catalytic system HCl-CrCl3(mass ratio5:1) had a good catalytic performance. When glucose was used as thereagent, the conversion of glucose was90.4%, and the yield of HMF reached42.5%under the optimum reaction conditions: glucose2.0g, composite catalytic systemHCl-CrCl3(mass ratio5:1)0.6g, n-butyl alcohol20mL, reaction time15min andreaction temperature200℃. When sucrose was used as the reagent, the conversion ofsucrose was100%, and the yield of HMF reached72.6%under the optimum reactionconditions: sucrose2.0g, composite catalytic system HCl-CrCl3(mass ratio5:1)0.8g,dimethyl sulfoxide20mL, reaction time30min and reaction temperature200℃.Both reactions catalyted by acidic ionic liquid were also studied, the resultsshowed that [HO3S-(CH2)3-mim]Cl had a better catalytic performance. In the reactionof glucose, the conversion was91.3%, and the yield reached43.8%under the optimumreaction conditions:2.0g, catalyst [HO3S-(CH2)3-mim]Cl0.4g, n-butyl alcohol20mL,reaction time15min and reaction temperature200℃. The yield of product was41.9%after reused5times. In the reaction of sucrose, the conversion was100%, and theyield reached76.4%.Under the optimum reaction conditions: sucrose2.0g, catalyst[HO3S-(CH2)3-mim]Cl0.7g, dimethyl sulfoxide20mL, reaction time30min andreaction temperature200℃. The yield of product was75.1%after reused5times. The results showed that Brφnsted ionic liquids had good reused performance.When Brφnsted-Lewis dual-acidic ionic liquids were used as catalysts in bothreactions, the results showed that [HO3S-(CH2)3-mim]Cl-CrCl3(x=0.55) had a goodcatalytic performance. Under the optimum reaction conditions of glucose2.0g,catalyst [HO3S-(CH2)3-mim]Cl-CrCl3(x=0.55)0.5g, n-butyl alcohol20mL, reactiontime15min and reaction temperature200℃, the conversion of glucose was91.4%,and the yield of HMF reached52.9%. The yield of product was52.4%after thecatslyst was reused5times. Under the optimum reaction conditions of sucrose2.0g,catalyst [HO3S-(CH2)3-mim]Cl-CrCl3(x=0.55)0.8g, dimethyl sulfoxide20mL,reaction time30min and reaction temperature200℃, the conversion of sucrose was97.7%, and the yield of HMF reached78.7%. The yield of product was78.4%afterreused5times. The results showed that Brφnsted ionic liquids had good reusedperformance.In summary, acidic functional ionic liquids was not only overcame the flaws ofconventional acids that can not be avoided, but also finished the work ofreaction-separation integration and the recycle of catalysts in the preparation process ofHMF from glucose and sucrose. This paper would provided effective support and basisfor the preparation process of HMF.