(253g) Lignin Derived Ionic Liquids: Synthesis and Application for Biopolymer Processing

Certain types of ionic liquids (ILs) have shown great solvation power for biopolymers, resulting in remarkable biomass pretreatment efficiency as well as novel approaches to produce biocomposites. To date, the best performing IL cations such as imidazolium and cholinium, are derived from petroleum and/or natural gas. ILs derived from inexpensive and renewable sources are thus highly desirable. Lignin is Earth’s most abundant, naturally-occurring aromatic polymer, and replacement of petroleum-based platforms with those derived from lignin represents a virtuous challenge for chemists. The synthesis of novel benzyl alkylammonium ILs from commercial lignin was performed using batch reactor systems followed by facile ion exchange chemistry. Both lignin oxidation and reduction has been studied to produce intermediates molecules for IL synthesis. The oxidation process has been scaled up to 10 L batch reactor followed by product recovery through filtration. Approximately 90% yields were achieved over three synthetic steps, and all product materials were fully characterized. The structure activity relationships of the lignin-derived ILs were evaluated for their ability to dissolve microcrystalline cellulose. A technoeconomic analysis and life cycle analysis has been performed to evaluate the economic viability and carbon footprint of the lignin-derived ionic liquid synthesis process.