School of Chemical and Material Engineering, Jiangnan University, Wuxi, Jiangsu 214122, China.
Carbohydr Polym. 2012 Jun 5;89(1):7-16. doi: 10.1016/j.carbpol.2012.01.080. Epub 2012 Feb 3.
Density functional theory calculations and atoms in molecules theory were performed to investigate the mechanism of cellulose dissolution and regeneration in 1-ethyl-3-methylimidazolium acetate ([emim]Ac), and (1,4)-dimethoxy-β-D-glucose (Glc) was chosen as the model for cellulose. The theoretical results show that the interaction of [emim]Ac with Glc is stronger than that of Glc with Glc. Further studies indicate that the anion acetate of [emim]Ac forms strong H-bonds with hydroxyl groups of Glc. It is also observed that the H-bonds between [emim]Ac and Glc are weakened or even destroyed by the addition of water. In addition, both the original and regenerated cellulose samples were characterized with FT-IR, XRD, TGA and SEM. The experimental results prove that cellulose can be readily reconstituted from the [emim]Ac-based cellulose solution by the addition of water and the crystalline structure of cellulose is converted to cellulose II from cellulose I in the original cellulose.
采用密度泛函理论计算和原子分子理论研究了纤维素在 1-乙基-3-甲基咪唑醋酸盐([emim]Ac)中的溶解和再生机制，选择(1,4)-二甲氧基-β-D-葡萄糖(Glc)作为纤维素的模型。理论结果表明，[emim]Ac 与 Glc 的相互作用强于 Glc 与 Glc 的相互作用。进一步的研究表明，[emim]Ac 的阴离子醋酸盐与 Glc 的羟基形成强氢键。还观察到，随着水的加入，[emim]Ac 与 Glc 之间的氢键被削弱甚至破坏。此外，对原始和再生纤维素样品进行了傅里叶变换红外光谱(FT-IR)、X 射线衍射(XRD)、热重分析(TGA)和扫描电子显微镜(SEM)分析。实验结果证明，纤维素可以很容易地从基于[emim]Ac 的纤维素溶液中通过加水重新形成，并且纤维素的结晶结构从纤维素 I 转化为纤维素 II。
