Beijing National Laboratory for Molecular Sciences, Key Laboratory of Colloid and Interface and Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Jiangxi Province Key Laboratory of Polymer Micro/Nano Manufacturing and Devices, Jiangxi Province Key Laboratory of Synthetic Chemistry, East China University of Technology, Nanchang 330013, China.
Sci Adv. 2023 Feb 3;9(5):eade7971. doi: 10.1126/sciadv.ade7971. Epub 2023 Feb 1.
Chemical transformation of spent polyesters into value-added chemicals is substantial for sustainable development but still challenging. Here, we report a simple, metal-free, and efficient aminolysis strategy to upcycle polylactic acid by anilines over lactate-based ionic liquids (e.g., tetrabutylammonium lactate), accessing a series of -aryl lactamides under mild conditions. This strategy is also effective for degradation of poly(bisphenol A carbonate), affording bisphenol A and corresponding diphenylurea derivatives. It is found that, with the assistance of water, lactate anion as hydrogen-bond donor can efficiently activate carbonyl C atom of polyesters via hydrogen bonding with carbonyl O atom; meanwhile, as hydrogen-bond acceptor, it can enhance nucleophilicity of the N atom of anilines via hydrogen bonding with amino H atom. The nucleophilic attack of N atom of anilines on carbonyl C atom of polyesters results in cleavage of C─O bond of polymers and formation of the target products.
将废旧聚酯化学转化为高附加值化学品对于可持续发展至关重要，但仍然具有挑战性。在这里，我们报告了一种简单、无金属且高效的氨解策略，即在基于乳酸盐的离子液体（例如四丁基乳酸铵）上用苯胺对聚乳酸进行循环利用，在温和条件下可获得一系列 -芳基内酰胺。该策略对于聚（双酚 A 碳酸酯）的降解也有效，可得到双酚 A 和相应的二苯脲衍生物。研究发现，在水的辅助下，乳酸盐阴离子作为氢键供体可通过与羰基 O 原子形成氢键有效地激活聚酯的羰基 C 原子；同时，作为氢键受体，它可通过与氨基 H 原子形成氢键增强苯胺 N 原子的亲核性。苯胺的 N 原子对聚酯的羰基 C 原子的亲核进攻导致聚合物的 C─O 键断裂，并形成目标产物。
