Review on development of ionic liquids in lignocellulosic biomass refining

Lignocellulosic biomass as the renewable and abundant resource in the earth can be transformed into bio-based chemicals and fuels with high added value, which is the preferable substitute for traditional fossil resources. The design and improvement of catalysts and pretreatment solvents are crucial to achieve the low-cost, efficient, and green conversion of biomass resources. Ionic liquids exhibit many advantages in biomass pretreatment and conversion because of their high catalytic efficiency, high solubility, unique molecular structure, and recyclable property. The present review aimed to summarize the research achievements and progress of ionic liquids as solvents or catalysts in the pretreatment of lignocellulosic biomass, transformation of polysaccharides into platform chemicals and isolation, depolymerization, and functional modification of lignin. The review concludes with a brief perspective on possible challenges and strategies for the sustainable development of ionic liquids in lignocellulosic biomass refining.