Abstract A series of phosphoric acid derivatives have been synthesised and their catalytic activity in the ring opening polymerisation of β-Butyrolactone (β-BL), ɛ-caprolactone and rac -lactide probed. Improved synthetic protocols and characterisation data are provided for a range of catalysts substituted with functional groups altering their electron density and p K a . Lower rates are observed for β-BL polymerisations than other aliphatic cyclic esters. By exploring the reaction kinetics and in situ NMR spectroscopy, we show that the activity decreases due to competitive formation of an off-cycle deactivated species through cleavage of catalyst P O bonds.

中文翻译：

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了解磷酸催化的 β-丁内酯和其他环酯的开环聚合

摘要 已经合成了一系列磷酸衍生物，并探测了它们在 β-丁内酯 (β-BL)、ɛ-己内酯和外消旋丙交酯的开环聚合中的催化活性。为一系列催化剂提供了改进的合成方案和表征数据，这些催化剂被官能团取代，改变了它们的电子密度和 p K a 。观察到 β-BL 聚合的速率低于其他脂肪族环酯。通过探索反应动力学和原位 NMR 光谱，我们表明由于通过催化剂 PO 键的裂解竞争性形成非循环失活物种，活性降低。