Yan Zhifeng, Lian Jie, Li Miaoting, Meng Lingyun, Zhang Yongfang, Ge Chao, Lu Jianjun
College of Textile Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China.
College of Textile Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China.
Int J Biol Macromol. 2020 Jul 1;154:596-605. doi: 10.1016/j.ijbiomac.2020.03.130. Epub 2020 Mar 17.
Aiming to get a deeper and accurate understanding on separation of polyester/cotton blended fabrics in subcritical water, the hydrolysis mechanisms of cellulose and polyester were studied using dispersion-corrected density functional theory (DFT-D) method with and without explicit HO under the conductor-like screening model (COSMO) set. The number and locations of explicit HO were determined by their likely functions including being dissociation and solvent and catalyst. The calculations disclosed that explicit HO provide inductive activation on glycosidic bond of cellulose and ester groups at the center of polyester and the assistance on the transfer of proton as proton-carrier and as catalyst of proton shuttle, affecting the reaction and activation energies in a realistic manner. In addition, the number of explicit HO molecules functioning as catalyst of proton shuttle may also has a strong influence on catalytic activity. Based on the improved explicit solvation models, the overall activation energies of proposed hydrolysis mechanisms for cellulose and polyester are 14.81 and 21.46 kcal/mol respectively, which explains the preferential hydrolysis of cellulose from experimental results.
为了更深入、准确地理解亚临界水中聚酯/棉混纺织物的分离，采用色散校正密度泛函理论（DFT-D）方法，在导体类屏蔽模型（COSMO）设定下，研究了有无显式HO时纤维素和聚酯的水解机理。显式HO的数量和位置由其可能的功能决定，包括解离、溶剂和催化剂。计算结果表明，显式HO对纤维素的糖苷键和聚酯中心的酯基提供诱导活化作用，并作为质子载体和质子穿梭催化剂协助质子转移，以实际方式影响反应和活化能。此外，作为质子穿梭催化剂的显式HO分子数量也可能对催化活性有很大影响。基于改进的显式溶剂化模型，纤维素和聚酯水解机理的总活化能分别为14.81和21.46 kcal/mol，这从实验结果解释了纤维素的优先水解。
