Ionic Liquids and Their Role in a Lignocellulosic Biorefinery

Ionic liquids (ILs), outstanding solvents for modifying lignocellulosic biomass, offer high biomass fractionation, yielding purer cellulosic and lignin fractions. The main benefits of ILs compared with other processes are the high degree of biomass fractionation and possibility of solvent recycle and reuse. While direct hemicellulose extraction remains a challenge, ILs facilitate the production of biobased platform chemicals through biochemical, chemical, and thermochemical routes. Aprotic ILs, despite high cellulose solubility, face cost barriers. In contrast, protic ILs, more cost-effective, efficiently solubilize lignin or both lignin and hemicelluloses. However, challenges such as scale-up, equipment corrosion, and IL recovery hinder the environmental and economic viability of IL-based biorefineries.