Purification of Kraft cellulose under mild conditions using choline acetate based deep eutectic solvents??

Green Chemistry Pub Date: 2020-11-11 DOI: 10.1039/D0GC03375H

Abstract

Three novel deep eutectic solvents (DESs) were prepared with choline acetate (ChOAc) as the hydrogen bond acceptor (HBA) and three hydrogen bond donors (HBD): glycolic acid (GlyA), levulinic acid (LevA) and imidazole (Im). They showed different, albeit remarkable capabilities of dissolving lignin (from 35% to 100%) and hemicellulose (from 40% to 50%). The solubility was first tested on commercially available hemicellulose in neat DES and in DES aqueous solution. The high values of solubility observed (22–45 wt%) demonstrated the potential of DESs as hemicellulose solvents. A proof of concept test was carried out on Kraft cellulose: our systems provided selective solubilisation of lignin and hemicellulose leading to cellulose purification, as demonstrated by the lignocellulosic content before and after the DES treatment.

Graphical abstract: Purification of Kraft cellulose under mild conditions using choline acetate based deep eutectic solvents
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