近年来，以胆碱类为代表的生物基离子液体作为木质素的优良溶剂逐渐受到广泛关注． 文中基于 Hansen 溶解理论，设计出一种分别以乳酸(LA)和氯化胆碱(ChCl)为氢键供受体的新型离子液体———深度共熔溶剂(DES)作为木质素分离的溶剂． 通过实验考察了常压下 ChCl/LA 摩尔比、温度、时间对木质素溶解效果的影响，确定了最佳工艺条件为 ChCl/LA 摩尔比1∶ 9、温度90℃、时间12h，此时木质素的溶解率达90． 1%，再生木质素纯度为 96． 3%．紫外可见光谱(UV)及红外光谱(FT-IR)分析表明木粉中木质素经 DES 处理后被大量脱除;X 射线衍射分析表明经预处理后的木粉中纤维素结构基本未被破坏;核磁共振谱( ¹³C NMR)分析表明再生木质素由紫丁香基、愈创木基及少量对羟苯基结构单元组成;离子色谱分析结果表明该混合溶液中的综纤维素只有少量发生溶解．

In recent years,choline,a novel kind of bio-based ILs (Ionic Liquids) used as a good lignin solvent,has been paid more and more attention to.In this paper,based on Hansen's theory of solubility,a novel ionic liquid analogue named DES (Deep Eutectic Solvent),in which lactic acid (LA) and choline chloride (ChCl) were respectively used as the donor and the acceptor of hydrogen bonds,was designed to separate lignin.Then,the dissolution results of lignin affected by the molar ratio of ChCl to LA,the reaction temperature and the interaction time were investigated by experiments.It was found that the dissolution rate of lignin reached the optimal 90. 1% and the purity of regenerated lignin reached 96. 3% at a ChCl-to-LA molar ratio of 1∶ 9,a reaction temperature 90℃ and a reaction duration of 12 h.The results of UV-Vis spectroscopy and FT-IR spectroscopy show that the lignin in the wood powders is greatly removed after DES treatment.XRD results show that the structure of cellulose in the pretreated wood powders is barely damaged.¹³C NMR results indicate that the regenerated lignin is mainly composed of syringyl,guaiacyl and a little p-hydroxylphengl.Moreover,ion chromatography results show that only a small amount of holocellulose is dissolved in the mixed solution.