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Extraction of lignins from aqueous–ionic liquid mixtures by organic solvents
Author(s) -
Xin Qin,
Pfeiffer Katie,
Prausnitz John M.,
Clark Douglas S.,
Blanch Harvey W.
Publication year - 2012
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.24337
Subject(s) - ionic liquid , chemistry , lignin , partition coefficient , cellulose , monomer , organic chemistry , aqueous solution , aqueous two phase system , solvent , extraction (chemistry) , dissolution , ethyl acetate , polymer , catalysis
The commercial development of ionic liquids (ILs) to pretreat lignocellulose by dissolution of whole biomass and cellulose precipitation by addition of water is hindered by the absence of an effective technique to recover the lignin content of the biomass from the IL. Three organic solvents [ethyl acetate, 1,4‐dioxane, and tetrahydrofuran (THF)] were studied for their ability to form a two‐liquid‐phase system with water and 1‐ethyl‐3‐methylimidazolium acetate ([C 2 mim][OAc]), and for partitioning model lignins and lignin monomers between the two liquid phases. Ternary diagrams were obtained for three [C 2 mim][OAc]/organic solvent/water systems at 22°C. Partition coefficients were measured for several types of lignin in these three systems. Partition coefficients increase with rising water content in the IL phase, and depend strongly on the type of lignin and on the organic solvent. Partition coefficients rise as the pH of the ionic‐liquid‐rich phase falls. Small molecule model lignin monomer compounds (guaiacol, syringaldehyde) are also readily extracted from the IL/water system by THF. Biotechnol. Bioeng. 2012; 109:346–352. © 2011 Wiley Periodicals, Inc.