Insight into dissolution mechanism of cellulose in [C4mim][CH3COO]/DMSO solvent by 13C NMR spectra

Recently, it has been reported that 1-butyl-3-methylimidazolium acetate/dimethyl sulfoxide ([C(4)mim] [CH3COO]/DMSO) can efficiently dissolve cellulose at room temperature. In the present study, C-13 NMR measurements of 1-butyl-3-methylimidazolium acetate [C(4)mim][CH3COO] and cellulose were carried out in [C(4)mim][CH3COO]/DMSO-d(6) (Deuterated dimethyl sulfoxide)/cellulose solution to directly reveal the possible dissolution mechanism of cellulose in true [C(4)mim][CH3COO]/DMSO solvent. The results indicate that both cation and anion of [C(4)mim][CH3COO] in [C(4)mim][CH3COO]/DMSO solvent dominate cellulose dissolution, and DMSO mainly serves to dissociate the ion pairs in [C(4)mim][CH3COO] into solvated cations and anions. Moreover, the hydrogen bonding interaction of anion of [C(4)mim][CH3COO] with cellulose hydroxyl proton is much stronger than that of cation of [C(4)mim][CH3COO] with cellulose hydroxyl oxygen. (C) 2015 Published by Elsevier B.V.