Development of cellulose-derived HMF production catalyzed by ion exchange resin in ionic liquid

采用离子交换树脂和离子液体等多相催化剂分别作为催化剂和溶剂，开发纤维素基HMF的多步反应（纤维素水解、葡萄糖异构化和果糖脱水）生产工艺。结果表明，连续加水对纤维素水解选择性产糖是有效的。结果表明，在水溶液中对葡萄糖异构化有效的碱催化剂在离子液体中失活。这可能是由于异相催化剂中的碱（或碱土）金属离子与离子液体中的Cl-（如[Bmim][Cl]）之间的强相互作用，使得材料上的活性位点受到毒害。另外，葡萄糖异构化成果糖是一个平衡反应，由于平衡约束，在较低温度下果糖的产率受到限制。为了克服这些问题，从葡萄糖直接生产HMF是有效的，必须尝试Lewis酸催化剂。为实现对能量有利的产物分离和溶剂的循环利用，液液萃取与精馏相结合是合适而有效的方法。

To develop cellulose-derived HMF production process, which includes multi-step reaction (cellulose hydrolysis, glucose isomerization and fructose dehydration), heterogeneous catalysts such as ion exchange resin and ionic liquid were employed as catalysts and solvent, respectively. It was found that sequential water addition was effective for selective glucose production via cellulose hydrolysis. It was revealed that alkali catalyst, which is normally effective for glucose isomerization in aqueous solution, became inactive in ionic liquid. Probably, this can be explained by strong interactions between alkali (or alkaline-earth) metal ion in heterogeneous catalysts and Cl- in ionic liquid (such as [Bmim][Cl]) such that active sites on the materials are poisoned. In addition, glucose isomerization into fructose is equilibrium reaction and fructose yield is limited at lower temperature because of the equilibrium constraint. To overcome these issues, direct production of HMF from glucose is effective and Lewis acid catalyst must be attempted. To accomplish energetically-favorable products separation and recycle of solvent, combination of liquid-liquid extraction with distillation would be appropriate and effective.