Catalytic Conversion of Carbohydrate Biomass in Ionic Liquids to 5-Hydroxymethyl Furfural and Levulinic Acid: A Review

The projections of ionic liquids as green solvents in chemical processes have increased in recent years. Ionic liquid is a versatile chemical with various applications. The aim of this review is to present a comprehensive perspective of ionic liquid for processing carbohydrate biomass by considering the recent progress in this field. Special attention is given to the application of ionic liquids for the production of 5-hydroxymethyl furfural (5-HMF) and levulinic acid (LA). Factors affecting the catalytic conversion of carbohydrate biomass in ionic liquid and the mechanisms of 5-HMF and LA production are also presented. In addition, the recyclability of the ionic liquid for carbohydrate biomass processing is discussed. The viewpoint for the application of functionalized ionic liquid as potential green solvent and catalyst is also highlighted. Future studies pertinent to carbohydrate biomass conversion in ionic liquids to 5-HMF and LA could use this review for selecting the appropriate reaction conditions required to achieve their specific goals. Besides, combination of technologies from ionic liquids and biomass processing strategies for the production of various fuels and value-added chemicals can be comprehended for applications in a lignocellulosic biorefinery.