Switchable Ionic Liquids as Delignification Solvents for Lignocellulosic Materials

Abstract

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 (CO2 and SO2 ) 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-SO2 -SIL treatment resulted in 80 wt % cellulose, 10 wt % hemicelluloses, and 3 wt % lignin, whereas MEA-CO2 -SIL treatment resulted in 66 wt % cellulose, 12 wt % hemicelluloses and 11 wt % lignin. Thus, the MEA-SO2 -SIL proved more efficient than the MEA-CO2 -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).

Relevance of the acidic 1-butyl-3-methylimidazolium hydrogen sulphate ionic liquid in the selective catalysis of the biomass hemicellulose fraction

“…[6][7][8][9][10][11][12][13][14][15][16][17][18][19]40 Recently, the ILs containing [HSO 4 ] anion became an appealing option to be used in the biomass pre-treatment, and the acidic properties of this IL allows for the catalytic conversion of biomass. [6][7][8][9][10][11][12][13][14][15][16][17][18][19]40 Recently, the ILs containing [HSO 4 ] anion became an appealing option to be used in the biomass pre-treatment, and the acidic properties of this IL allows for the catalytic conversion of biomass.…”

“…4 However, to achieve this goal various challenges must be addressed. 5 One of the approaches is the use of more sustainable solvents such as ionic liquids [6][7][8][9][10][11][12][13][14][15][16][17][18][19] and supercritical uids. In addition, the choice of pre-treatment should consider the overall compatibility of feedstocks, enzymes and organisms to be applied, overall economic assessment and environmental impact.…”

Switchable ionic liquids enable efficient nanofibrillation of wood pulp

“…Bleaching of the SIL treated biomass was performed using acid chlorite bleaching following a previously described procedure by Anugwom et al (2014a). Briefly a sample of 1 g was bleached with 0.8 g NaClO 2 and 0.16 g AcOH in 40 ml water, at 75°C for 2 h and the chemicals were added in two portions.…”

Dissolution and regeneration behavior of chitosan in 3-methyl-1-(ethylacetyl)imidazolium chloride

“…Ionic liquids (ILs) are defined as organic molten salts with melting temperature below 100 o C. ILs have unique properties, such as non-detectable vapor pressure, low melting point, high chemical and thermal stability, non-flammability, and chemical tunabilities, which make them have been extensively applied in catalytic reactions, organic synthesis, functional materials, life science and electrochemical reactions [9][10][11][12][13][14]. Research has shown that ILs is effective for the dissolution of cellulose [15][16][17][18][19][20][21].…”