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Deep Eutectic Solvent Aqueous Solutions as Efficient Media for the Solubilization of Hardwood Xylans
Author(s) -
Morais Eduarda S.,
Mendonça Patrícia V.,
Coelho Jorge F. J.,
Freire Mara G.,
Freire Carmen S. R.,
Coutinho João A. P.,
Silvestre Armando J. D.
Publication year - 2018
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.201702007
Subject(s) - chemistry , aqueous solution , extraction (chemistry) , xylan , hardwood , furfural , deep eutectic solvent , choline chloride , solvent , organic chemistry , chromatography , eutectic system , catalysis , hydrolysis , ecology , alloy , biology
This work contributes to the development of integrated lignocellulosic‐based biorefineries by the pioneering exploitation of hardwood xylans by solubilization and extraction in deep eutectic solvents (DES). DES formed by choline chloride and urea or acetic acid were initially evaluated as solvents for commercial xylan as a model compound. The effects of temperature, molar ratio, and concentration of the DES aqueous solutions were evaluated and optimized by using a response surface methodology. The results obtained demonstrated the potential of these solvents, with 328.23 g L −1 of xylan solubilization using 66.7 wt % DES in water at 80 °C. Furthermore, xylans could be recovered by precipitation from the DES aqueous media in yields above 90 %. The detailed characterization of the xylans recovered after solubilization in aqueous DES demonstrated that 4‐ O ‐methyl groups were eliminated from the 4‐ O ‐methylglucuronic acids moieties and uronic acids (15 %) were cleaved from the xylan backbone during this process. The similar M w values of both pristine and recovered xylans confirmed the success of the reported procedure. DES recovery in four additional extraction cycles was also demonstrated. Finally, the successful extraction of xylans from Eucalyptus globulus wood by using aqueous solutions of DES was demonstrated.