title: Dialkyl phosphate-related ionic liquids as selective solvents for xylan.
abstract: Herein we describe a possibility of selective dissolution of xylan, the most important type of hemicellulose, from Eucalyptus globulus kraft pulp using ionic liquids (ILs). On the basis of the IL 1-butyl-3-methylimidazolium dimethyl phosphate, which is well-known to dissolve pulp, the phosphate anion was modified by substituting one oxygen atom for sulfur and selenium, respectively. This alteration reduces the hydrogen bond basicity of the IL and therefore prevents dissolution of cellulose fibers, whereas the less ordered xylan is still dissolved. (1)H NMR spectra of model solutions and Kamlet-Taft parameters were used to quantify the solvent polarity and hydrogen bond acceptor properties of the ILs. These parameters have been correlated to their ability to dissolve xylan and cellulose, which was monitored by (13)C NMR spectroscopy. It was found that the selectivity for xylan dissolution increases to a certain extent with decreasing hydrogen-bond-accepting ability of anions of the ILs.
authors.affiliation: Faculty of Chemistry and Pharmacy, University of Innsbruck, 6020 Innsbruck, Austria. Carmen.Froschauer@uibk.ac.at
authors.forename: Carmen
authors.initials: C
authors.lastname: Froschauer
authors.forename: Michael
authors.initials: M
authors.lastname: Hummel
authors.forename: Gerhard
authors.initials: G
authors.lastname: Laus
authors.forename: Herwig
authors.initials: H
authors.lastname: Schottenberger
authors.forename: Herbert
authors.initials: H
authors.lastname: Sixta
authors.forename: Hedda K
authors.initials: HK
authors.lastname: Weber
authors.forename: Gerhard
authors.initials: G
authors.lastname: Zuckerstätter
mesh_terms: D005052:Eucalyptus / Q000737:chemistry; D052578:Ionic Liquids / Q000737:chemistry*; D009943:Organophosphorus Compounds / Q000737:chemistry*; D010316:Particle Size; D012997:Solvents / Q000737:chemistry; D013499:Surface Properties; D014990:Xylans / Q000737:chemistry*
chemical_list: D052578:Ionic Liquids; D009943:Organophosphorus Compounds; D012997:Solvents; D014990:Xylans