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Ionic (Co)Organocatalyst with (Thio)Urea Anion and Tetra‑n‑butyl Ammonium Cation for the Polymerization of γ‐Butyrolactone
Macromolecular Chemistry and Physics ( IF 2.5 ) Pub Date : 2020-07-19 , DOI: 10.1002/macp.202000172
Ge Fang 1 , Wang Zhe 2 , Zhu Yanyun 1 , Wang Xiaowu 2
Affiliation  

An effective ionic organocatalyst system is developed for the challenging ring‐opening polymerization (ROP) of γ‐butyrolactone (GBL) at low temperature. The catalysts are prepared by dehydration reaction between tetra‐n‐butyl ammonium hydroxide (TBAOH) and (thio)ureas at ambient temperature, and utilized with or without extra benzyl alcohol (BnOH) initiator. The solid‐state structure of TUA‐3 comprising thiourea anion is characterized by X‐ray diffraction analysis. Typically, a mixture of cyclic and linear poly(GBL) with low molecular weights (5000–1600 g mol−1) and slightly narrow molecular distribution Ð (1.2–1.4) is obtained by single base with/without combination with (thio)ureas. Interestingly, solely linear high‐molecular‐weight poly(GBL) (10 400 g mol−1) can be achieved by a synergistic effect of TBAOH/N,N′‐isopropylthiourea in the presence of BnOH. The obtained poly(GBL) is characterized with NMR spectroscopy and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectroscopy (MALDI‐TOF MS). Mechanistic studies reveal different polymerization initiation steps in this reported catalyst system, which leads to poly(GBL) with divergent end groups.

中文翻译:

离子(钴)有机催化剂与(硫代)尿素阴离子和四正丁基铵阳离子聚合γ-丁内酯

开发了一种有效的离子型有机催化剂体系,用于低温下具有挑战性的γ-丁内酯(GBL)的开环聚合(ROP)。催化剂是在环境温度下通过氢氧化四丁基铵铵(TBAOH)和(硫代)脲之间的脱水反应制备的,并与或不与额外的苄醇(BnOH)引发剂一起使用。X射线衍射分析表征了包含硫脲阴离子的TUA-3的固态结构。通常情况下,环状和直链的聚(GBL)具有低分子量的混合物(5000-1600克摩尔-1)和略窄的分子量分布d(1.2-1.4)通过与/单碱基而不结合(硫代)脲得到。有趣的是,单线性高分子量聚(GBL)(10 400 g mol-1)可以通过在BnOH存在下TBAOH / N,N'-异丙基硫脲的协同作用来实现。获得的poly(GBL)用NMR光谱和基质辅助激光解吸/电离飞行时间质谱(MALDI-TOF MS)进行表征。机理研究揭示了在该报道的催化剂体系中不同的聚合引发步骤,这导致了具有不同端基的聚(GBL)。
更新日期:2020-07-19
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