Decomposition of a phenolic lignin model compound over organic N-bases in an ionic liquid

Abstract

Lignin depolymerization is a necessary process step in utilizing the carbohydrates in biomass and in potentially converting the lignin into a chemical feedstock. Lignin contains several aryl-alkyl ether linkages and the β-O-4 linkage is dominant among lignins. Base-mediated cleavage of the β-O-4 bond in a lignin model compound, guaiacylglycerol-β-guaiacyl ether, is reported. Ionic liquids have shown promise in a variety of biomass processes and this study explores the potential to use an ionic liquid solvent (1-butyl-2,3-dimethylimidazolium chloride) and non-aqueous bases in cleaving the β-O-4 bond. N-bases of varying basicity and structure were used at temperatures up to 150°C. The cleavage reaction was not found to be catalytic. Among all the tested N-bases, 1,5,7-triazabicyclo[4.4.0]dec-5-ene was the most active, leading to more than 40% β-O-4 ether bond cleavage, and the higher activity is probably associated with the exposed nature of the N-atoms.

Catalytic transformation of carbohydrates and lignin in ionic liquids

“…Strong organic bases were studied for their catalytic activity in catalyzing the hydrolysis of the β‒O‒4 ether linkage in GG and VG . [BDMIM[Cl was used as a solvent for this work because of the reported instability of most common dialkyl‐substituted imidazolium‐based ionic liquids under basic conditions.…”

Dissolution and acetylation of ball-milled birch (Betula platyphylla) and bamboo (Phyllostachys nigra) in the ionic liquid [Bmim]Cl for HSQC NMR analysis

“…ILs are environmentally friendly recyclable solvents and have attracted increasing attention as solvents for biomass dissolution (Honglu and Tiejun 2006 ;Stasiewicz et al 2008 ;Jia et al 2010 ;Liebner et al 2010 ;Nakamura et al 2010 ;Viell and Marquardt 2011 ). The IL 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) ( Figure 1 ) is one of the most commonly used ILs for biomass dissolution.…”

Dissolution and acetylation of ball-milled lignocellulosic biomass in ionic liquids at room temperature: application to nuclear magnetic resonance analysis of cell-wall components

“…Ionic liquids (ILs) are eco-friendly solvents with a potential to be applied in biomass refi nery as shown by increasing research activities on IL in the context of wood research (Honglu and Tiejun 2006 ;Stasiewicz et al 2008 ;Jia et al 2010 ;Liebner et al 2010 ;Nakamura et al 2010 ;Viell and Marquardt 2011 ). ILs have many advantages, such as tunable physicochemical properties, negligible vapor pressure, and thermal stability.…”