Ionic Liquids as Organocatalysts and Solvents for Lignocellulose Reactions

• Published in: Chemical record 2023-08, Vol.23 (8), p.e202200264-n/a
• Main Authors: Suzuki, Shiori, Takahashi, Kenji
• Format: Article
• Language: English
• Subjects: Anions; Atom economy; Catalytic activity; Cations; Cellulose; Chemical modification; Fractionation; homogeneous reaction; ionic liquid; Ionic liquids; Lignocellulose; organocatalysis; Polymers; twin-screw extruder
• ISSN: 1527-8999; 1528-0691
• DOI: 10.1002/tcr.202200264

Ionic liquids (ILs) are the only media that can allow the homogeneous organocatalytic reactions of lignocellulosic biomass (lignocellulose), since the designability of their cations and anions offers the dual functions of solubility and catalytic activity. This review provides an account of our recent achievements in the organocatalytic approaches for converting lignocellulose into polymer materials based on the principles of IL design that we have originally established. These methodologies include the simple and mild chemical modification of cellulose and lignin under high conversions, with high selectivity, and/or with efficient atom economy. Similar reactions and subsequent fractionation processes are applied to lignocellulose, and a highly productive reaction system is developed using a twin‐screw extruder that is specific to the IL media. Ionic liquids (ILs) are distinctive organic salts that can dissolve lignocellulosic biomass and can also act as organocatalysts for homogeneous chemical modification reactions. IL catalysis varies depending on the designable structures of the cation and the anion, while the non‐distillable nature and viscosity of ILs can be exploited as ingenious synthetic strategy for the sustainable and scalable production of lignocellulosic materials. The recent advances in our group are summarized in this Personal Account.