Li Li, Zhang Maozhi, Feng Yun, Zhang Xun, Xu Feng
Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing 100083, China; Engineering Research Center of Forestry Biomass Materials and Energy, Ministry of Education, Beijing Forestry University, Beijing 100083, China.
Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing 100083, China; Engineering Research Center of Forestry Biomass Materials and Energy, Ministry of Education, Beijing Forestry University, Beijing 100083, China.
Carbohydr Polym. 2024 Sep 1;339:122260. doi: 10.1016/j.carbpol.2024.122260. Epub 2024 May 13.
A deep eutectic solvent (DES) formulated with tetramethylammonium hydroxide pentahydrate /urea (TMAH·5HO/Urea) was designed for the first time to dissolve cellulose at room temperature. The optimized system, characterized by a 1:3 M ratio, demonstrates the capability to dissolve approximately 7.5 wt% cellulose, boasting a high degree of polymerization (DP = 526). Notably, both the pure DES and 4.0 wt% cellulose/TMAH·5HO/Urea mixtures manifests low viscosity, establishing its potential as an effective spinning aid in fiber manufacturing. The structural analyses shows that the cellulose crystal type shifts from type I to type II form, accompanied by a reduction in both crystallinity and DP. A pivotal aspect of this research involves determining Kamlet-Taft parameters for TMAH·5HO/Urea-DES with different molar ratios. The results reveal these solvate DESs exhibit the high hydrogen bond basicity, which enables them to easily form hydrogen bonds with hydroxyl groups of cellulose and demonstrate good cellulose solubility. In conclusion, this solvent system presents notable advantages, including straightforward synthesis procedures, low viscosity, and well cellulose solubility, paving the way for new approaches and techniques in cellulose utilization.
首次设计了一种由五水合氢氧化四甲铵/尿素（TMAH·5H₂O/尿素）配制的深共熔溶剂（DES），用于在室温下溶解纤维素。以1:3的摩尔比为特征的优化体系显示出能够溶解约7.5 wt%的纤维素，具有高度的聚合度（DP = 526）。值得注意的是，纯DES和4.0 wt%纤维素/TMAH·5H₂O/尿素混合物都表现出低粘度，确立了其作为纤维制造中有效纺丝助剂的潜力。结构分析表明，纤维素晶体类型从I型转变为II型，同时结晶度和DP都降低。本研究的一个关键方面涉及确定不同摩尔比的TMAH·5H₂O/尿素-DES的Kamlet-Taft参数。结果表明，这些溶剂化DES表现出高氢键碱度，这使它们能够轻松地与纤维素的羟基形成氢键，并表现出良好的纤维素溶解性。总之，这种溶剂体系具有显著优势，包括合成过程简单、粘度低和纤维素溶解性好，为纤维素利用的新方法和新技术铺平了道路。
