酸性离子液体中果糖脱水制备5-羟甲基糠醛

Dehydration of Fructose in Presence of Acidic Ionic Liquids to Prepare 5-Hydroxymethylfurfural

制备了多种离子液体,并将其作为催化剂和溶剂催化果糖脱水制备5-羟甲基糠醛(HMF)。制备的酸性离子液体包括磺酸基功能化酸性离子液体、咪唑类酸性离子液体和吡啶类酸性离子液体。利用核磁共振仪和红外光谱仪对离子液体的结构进行表征。利用紫外可见光分光光度计结合Hammett指示剂计算Hammett酸度函数,比较了酸强度的大小对反应的影响。结果表明,离子液体的酸强度对反应有较大影响,在无其它催化剂和溶剂的情况下,离子液体具有较高的催化活性,通过使用1-丁基-3-甲基咪唑氯盐(BmimCl)作为催化剂,当反应温度为120℃,反应进行到4 h时,HMF收率可以达到74.97%。

Conversion of fructose into 5-hydroxymethylfurfural（HMF） was investigated in various acidic ionic liquids as catalyst and solvent. The acidic ionic liquids include SO3 H functionalized ionic liquids, imidazole- based ionic liquids and pyridine-based acid ionic liquids. The catalysts were characterized by NMR and IR. The Hammett acidity function was obatined by UV-Vis measurements with an Hammett indicator. The acid strength was compared. The results show that the acid strength of catalysts affects the reaction. Ionic liquid has a high activity without the addition of other catalyst and solvent. When 1-butyl-3-methylimidazolium chloride（BmimC1） was used as the catalyst, the yield of HMF was 74. 97% within 4 h at 120℃.