Meng Xiangqian, Devemy Julien, Verney Vincent, Gautier Arnaud, Husson Pascale, Andanson Jean-Michel
CNRS, SIGMA Clermont, Institut de Chimie de Clermont-Ferrand, Université Clermont Auvergne, 63000, Clermont-Ferrand, France.
ChemSusChem. 2017 Apr 22;10(8):1749-1760. doi: 10.1002/cssc.201601830. Epub 2017 Mar 9.
Twenty ionic liquids based on tetraalkylammonium cations and carboxylate anions have been synthesized, characterized, and tested for cellulose dissolution. The amount of cellulose dissolved in these ionic liquids depends strongly on the size of the ions: from 0 to 22 wt % cellulose can be dissolved at 90 °C. The best ionic liquids are less viscous and ammonium carboxylate based ionic liquids can dissolve as much as imidazolium-based ones. The viscosity of an ionic liquid can be decreased by the addition of DMSO as a cosolvent. After the addition of cosolvent, similar amounts of cellulose per ions are reached for most ionic liquids. As observed by rheology, ionic liquids with the longest alkyl chains form a gel when a high amount of cellulose is dissolved; this drastically limits their potential. Molecular simulations and IR spectroscopy have also been used with the aim of understanding how molecular interactions differ between efficient and inefficient ionic liquids.
已合成、表征并测试了二十种基于四烷基铵阳离子和羧酸盐阴离子的离子液体用于纤维素溶解。溶解在这些离子液体中的纤维素量强烈依赖于离子的大小：在90°C时，可溶解的纤维素量从0至22 wt%不等。最佳的离子液体粘度较低，且基于羧酸铵的离子液体能够溶解与基于咪唑鎓的离子液体一样多的纤维素。通过添加二甲基亚砜作为共溶剂可以降低离子液体的粘度。添加共溶剂后，大多数离子液体每离子溶解的纤维素量相近。流变学观察表明，当溶解大量纤维素时，具有最长烷基链的离子液体形成凝胶；这极大地限制了它们的潜力。还使用了分子模拟和红外光谱来理解高效和低效离子液体之间分子相互作用的差异。
