Lignin is an abundant renewable feedstock to potentially produce aromatics, phenolics, and cyclic alkanes. Lignin fractionation from biomass is a critical step for biomass utilization, not only in the potential value of the isolated lignin, but also in enabling the utilization of the remaining polysaccharides. The lignin crust has been identified as one of the major obstacles for an energy-efficient biomass deconstruction process. Lignin can be isolated in large quantity from lignocellulosic materials by strong dilute acid treatment, alkaline treatment, organosolve isolation or sulphite pulping process. These traditional pretreatment methods, have been mostly developed for biomass utilization, but they in general carry serious environmental consequences, strong corrosion, and some involve energy intensive processes.<br/>In this work, a series of amine-sulfonate functionalized ionic liquids (ASF-ILs) were synthesized, characterized, and first evaluated for the dissolution of model biopolymers (cellulose, xylan, kraft lignin and lignosulfonate). Most of the ASF-ILs dissolve kraft lignin and lignosulfonate efficiently at 373 K, with solubilities of 0.220–0.385g for kraft lignin and of 0.150-0.290 g for lignosulfonate per gram of ASF-ILs. In contrast, xylan and cellulose are scarcely soluble (&lt;5mg g-1) in the ASF-ILs. Based on the results of the model lignin dissolution, four most promising ASF-ILs were selected and applied for the pretreatment of eucalyptus bark. The lignin was selectively fractionated by the ASF-ILs with lignin removal efficiency of &gt;40%. The fractionated lignin and the eucalyptus bark residues were then characterized by infrared spectroscopy and thermo gravimetric analysis.

Biomass lignin fractionation using amine-sulfonate functionalized ionic liquids

251st National Meeting (2016)

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