Selective Modification of Aliphatic Hydroxy Groups in Lignin Using Ionic Liquid
نویسندگان
چکیده
A facile, sustainable method for the selective modification of aliphatic hydroxy (R–OH) groups in Kraft lignin was developed using an ionic liquid, 1-ethyl-3-methylimidazolium acetate (EmimOAc), as a solvent and catalyst. Selective R–OH achieved by one-pot, two-step homogeneous reaction: (i) acetylation aromatic OH (Ar–OH) with isopropenyl (IPAc) acyl donor (ii) subsequent deacetylation generated acetyl (Ar–OAc) groups. In step (i), IPAc reacts rapidly Ar–OH but slowly R–OH. The Ar–OAc is gradually deacetylated heating EmimOAc, whereas (R–OAc) are chemically stable. (ii), all acetylated which better than IPAc, contributing to rapid remaining R–OH, residual completed adding tiny amount water proton source. This reaction resulted (>99%) being almost (93%). Selectively modified obtained acceptably high isolated yield (85%) repeatability (N = 3). Furthermore, despite lower substitution degree, it exhibited solubility common solvents, heat-meltability, thermal stability comparable completely lignin.
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ژورنال
عنوان ژورنال: Catalysts
سال: 2021
ISSN: ['2073-4344']
DOI: https://doi.org/10.3390/catal11010120