College of Food Science and Light Industry, Nanjing Tech University, Nanjing, 211800, China.
College of Food Science and Light Industry, Nanjing Tech University, Nanjing, 211800, China; Institute of Textile Chemicals and Ecological Dyeing and Finishing, Nanjing Tech University, Nanjing, 211800, China.
Carbohydr Polym. 2018 Sep 1;195:288-297. doi: 10.1016/j.carbpol.2018.04.097. Epub 2018 Apr 26.
Chitosan dissolution system with [Emim]Ac (1-ethyl-3-methylimidazolium acetate) and urea was designed for homogeneous chemical modification of chitosan. Physicochemical properties of [Emim]Ac and [Emim]Ac-urea, such as density, solvatochromic parameters etc, were thoroughly investigated. NMR and FTIR spectra of [Emim]Ac-Urea solution were tested for determination of interaction between [Emim]Ac and urea. Obvious chemical shift change (Δd) of typical atoms (H2, H11, C10, and C12) in [Emim]Ac-urea indicated that strong hydrogen bonds were formed between [Emim]Ac and urea. Chitosan dissolution performance in [Emim]Ac-Urea solution was studied. Density functional theory (DFT) simulations were carried out to discuss the interactions between [Emim]Ac, urea, and chitosan. Four kinds hydrogen bonds (CH/O, CH/N, NH/O, NH/N), and eight hydrogen bonds, were formed in chitobiose-[Emim]Ac-urea. In particular, anion acetate of [Emim]Ac, hydrogen atoms and nitrogen of urea formed strong hydrogen bonds with oxygen atoms, amide, and hydroxyl in chitobiose. The information obtained would provide a guide for the development of novel solvent systems for chitosan dissolution and homogeneous chemical modification.
设计了含有[Emim]Ac（乙酸 1-乙基-3-甲基咪唑）和尿素的壳聚糖溶解体系，用于壳聚糖的均相化学修饰。深入研究了[Emim]Ac 和[Emim]Ac-尿素的物化性质，如密度、溶剂化参数等。通过 NMR 和 FTIR 光谱测试了[Emim]Ac-尿素溶液，以确定[Emim]Ac 和尿素之间的相互作用。[Emim]Ac-尿素中典型原子（H2、H11、C10 和 C12）的明显化学位移变化（Δd）表明[Emim]Ac 和尿素之间形成了强氢键。研究了壳聚糖在[Emim]Ac-尿素溶液中的溶解性能。进行了密度泛函理论（DFT）模拟，以讨论[Emim]Ac、尿素和壳聚糖之间的相互作用。在壳二糖-[Emim]Ac-尿素中形成了四种氢键（CH/O、CH/N、NH/O、NH/N）和八种氢键。特别是[Emim]Ac 的乙酸盐阴离子、尿素的氢原子和氮原子与壳二糖中的氧原子、酰胺和羟基形成了强氢键。所得信息将为壳聚糖溶解和均相化学修饰的新型溶剂体系的开发提供指导。
