Design and synthesis of Bronsted-Lewis acidic tetraimidazolyl ionic liquids for efficient catalytic conversion of glucose to 5-hydroxymethylfurfural in water/1-octanol

A series of Bronsted-Lewis acidic tetraimidazolyl ionic liquids ([TeimILs]) were designed and synthesized by introducing Bronsted acid (-SO3H) in the cation and Lewis acid (AlCl3) in the anion. Among them, [Teim-PS] [AlCl4]4 exhibited good catalytic performance in the conversion of glucose to 5-HMF in the biphasic system of H2O: 1-octanol= 1:2, and the conversion of glucose and the yield of 5-HMF can reach 95.4 % and 71.3 %, respectively. [Teim-PS][AlCl4]4 as the catalyst can be reused at least six times, the yield of 5-HMF does not decrease significantly. The biphasic system was beneficial for the recycling of [Teim-PS][AlCl4]4 and the separation of 5-HMF. The catalytic system also has good applicability to the degradation of other carbohydrate compounds. In addition, the kinetic analysis was performed on the catalytic system, and its activation energy was only 49.98 KJ/mol. This work provides a new solution for the efficient and green conversion of glucose to 5-HMF.

Automated summary

A series of Bronsted-Lewis acidic tetraimidazolyl ionic liquids ([TeimILs]) were designed and synthesized, and [Teim-PS] [AlCl4]4 showed good catalytic performance in the conversion of glucose to 5-HMF with a biphasic system. The catalyst could be reused multiple times without significant decrease in yield. The biphasic system facilitated catalyst recycling and separation of 5-HMF. The catalytic system also exhibited applicability to the degradation of other carbohydrate compounds, and had a low activation energy of 49.98 KJ/mol. This work provides a new solution for the efficient and green conversion of glucose to 5-HMF.