Abstract

Development of efficient solvents to dissolve lignocellulose and its main components is of significant importance for the utilization/transformation of lignocellulose. Herein, several ionic liquid (IL)-based deep eutectic solvents (DESs) were prepared using four ILs as the hydrogen bond acceptors and four different hydrogen bond donors, including thiourea (TU), N-methylthiourea (NMTU), glycerol (Gly), and ethylene glycol (EG). Using the dissolution of xylan (a typical type of hemicellulose) as the example, it was observed that the synthesized IL-based DESs could efficiently dissolve xylan. Especially in the DES formed from 1-allyl-3-methylimidazolium chloride and EG, the xylan solubility could reach as high as 40.4 wt% at 343.15 K. More importantly, the solubility of xylan in IL-based DESs was much higher than that in the corresponding IL. The enhancement effect might be ascribed to that the formation of DESs could significantly decrease the viscosity and increase the hydrogen bond accepting ability. Additionally, the regeneration of the xylan from the DESs could be easily realized using ethanol as the anti-solvent, and the regenerated xylan kept a high consistency with the original xylan.

Graphic abstract

Ionic liquid-based deep eutectic solvents were designed for highly efficient dissolution of xylan owing to the decreased viscosity and the increased hydrogen-bond accepting ability.

中文翻译：

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木聚糖在离子液体基深共熔溶剂中的高效溶解

摘要

开发有效的溶剂以溶解木质纤维素及其主要成分对于木质纤维素的利用/转化具有重要意义。在此，使用四个ILs作为氢键受体和四个不同的氢键供体，包括硫脲（TU），N-甲基硫脲（NMTU），甘油（Gly），制备了几种基于离子液体（IL）的深共熔溶剂（DES）。和乙二醇（EG）。以木聚糖（典型的半纤维素类型）的溶解为例，观察到合成的基于IL的DES可以有效地溶解木聚糖。特别是在由1-烯丙基-3-甲基咪唑鎓氯化物和EG形成的DES中，木聚糖的溶解度在343.15 K时可高达40.4 wt％。更重要的是，木聚糖在IL基DES中的溶解度远高于相应的IL。增强作用可以归因于DES的形成可以显着降低粘度并增加氢键接受能力。另外，使用乙醇作为抗溶剂，可以容易地实现从DES中的木聚糖的再生，并且再生的木聚糖与原始木聚糖保持高度一致性。

图形摘要

离子液体基深共晶溶剂由于粘度降低和氢键接受能力增强而设计用于木聚糖的高效溶解。