Lin Ya-Fan, Jheng Nai-Yuan
Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
Polymers (Basel). 2019 Sep 19;11(9):1530. doi: 10.3390/polym11091530.
The reactivity and the reaction conditions of the ring-opening polymerization of -caprolactone (-CL) and -lactide (LA) initiated by aluminum ketiminate complexes have been shown differently. Herein, we account for the observation by studying the mechanisms on the basis of density functional theory (DFT) calculations. The calculations show that the ring-opening polymerization of -CL and LA are rate-determined by the benzoxide insertion and the C-O bond cleavage step, respectively. Theoretical computations suggest that the reaction temperature of -LA polymerization should be higher than that of -CL one, in agreement with the experimental data. To provide a reasonable interpretation of the experimental results and to give an insight into the catalyst design, the influence of the electronic, steric, and thermal effects on the polymerization behaviors will be also discussed in this study.
已表明由铝酮亚胺配合物引发的ε-己内酯（ε-CL）和丙交酯（LA）的开环聚合反应活性和反应条件有所不同。在此，我们通过基于密度泛函理论（DFT）计算研究其机理来解释这一观察结果。计算表明，ε-CL和LA的开环聚合反应速率分别由苯氧基插入和C-O键断裂步骤决定。理论计算表明，LA聚合反应的温度应高于ε-CL聚合反应的温度，这与实验数据一致。为了合理解释实验结果并深入了解催化剂设计，本研究还将讨论电子、空间和热效应对聚合行为的影响。
