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Switchable Ionic Liquids as Delignification Solvents for Lignocellulosic Materials
Author(s) -
Anugwom Ikenna,
Eta Valerie,
Virtanen Pasi,
MäkiArvela Päivi,
Hedenström Mattias,
Hummel Michael,
Sixta Herbert,
Mikkola JyriPekka
Publication year - 2014
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201300773
Subject(s) - lignin , chemistry , cellulose , ionic liquid , fractionation , solvent , fourier transform infrared spectroscopy , lignocellulosic biomass , amine gas treating , organic chemistry , chromatography , chemical engineering , catalysis , engineering
The transformation of lignocellulosic materials into potentially valuable resources is compromised by their complicated structure. Consequently, new economical and feasible conversion/fractionation techniques that render value‐added products are intensely investigated. Herein an unorthodox and feasible fractionation method of birch chips ( B. pendula ) using a switchable ionic liquid (SIL) derived from an alkanol amine (monoethanol amine, MEA) and an organic super base (1,8‐diazabicyclo‐[5.4.0]‐undec‐7‐ene, DBU) with two different trigger acid gases (CO 2 and SO 2 ) is studied. After SIL treatment, the dissolved fractions were selectively separated by a step‐wise method using an antisolvent to induce precipitation. The SIL was recycled after concentration and evaporation of anti‐solvent. The composition of undissolved wood after MEA‐SO 2 ‐SIL treatment resulted in 80 wt % cellulose, 10 wt % hemicelluloses, and 3 wt % lignin, whereas MEA‐CO 2 ‐SIL treatment resulted in 66 wt % cellulose, 12 wt % hemicelluloses and 11 wt % lignin. Thus, the MEA‐SO 2 ‐SIL proved more efficient than the MEA‐CO 2 ‐SIL, and a better solvent for lignin removal. All fractions were analyzed by gas chromatography (GC), Fourier transform infrared spectroscopy (FT‐IR), 13 C nuclear magnetic resonance spectroscopy (NMR) and Gel permeation chromatography (GPC).