瑞士苏黎世联邦理工学院Choi Tae-Lim团队报道了“隔离”多相催化剂实现纯循环聚合物的可扩展和连续制备。相关研究成果于2022年9月5日发表于国际一流学术期刊《自然化学 》。

环状聚合物在拓扑结构上很有趣，被认为是一种润滑材料。然而，纯环状聚合物的可扩展合成仍然难以捉摸。最直接的方法是在合成环状聚合物后回收使用过的催化剂并重新使用。不幸的是，由于催化剂的脆弱性和与聚合物的不可分离性，这降低了工艺的实用性。

该文中，研究人员开发了一种连续循环工艺，其中聚合、聚合物分离和催化剂回收在原位进行，以在环戊烯的体环膨胀复分解聚合后分配一个纯环状聚合物。这是通过引入二氧化硅负载的钌催化剂和新设计的玻璃器皿实现的。研究人员还讨论了环状聚合物与其线性类似物的不同解聚动力学。随着稀土催化剂的循环次数(≥415,000次)的增加，该工艺最大限度地减少了人工操作，最大限度地提高了易损催化剂的安全性，并保证了循环聚合物的纯度，从而展示了一种可扩展的循环聚合物的原型。

附：英文原文

Title: Scalable and continuous access to pure cyclic polymers enabled by ‘quarantined’ heterogeneous catalysts

Author: Yoon, Ki-Young, Noh, Jinkyung, Gan, Quan, Edwards, Julian P., Tuba, Robert, Choi, Tae-Lim, Grubbs, Robert H.

Issue&Volume: 2022-09-05

Abstract: Cyclic polymers are topologically interesting and envisioned as a lubricant material. However, scalable synthesis of pure cyclic polymers remains elusive. The most straightforward way is to recover a used catalyst after the synthesis of cyclic polymers and reuse it. Unfortunately, this is demanding because of the catalyst’s vulnerability and inseparability from polymers, which reduce the practicality of the process. Here we develop a continuous circular process, where polymerization, polymer separation and catalyst recovery happen in situ, to dispense a pure cyclic polymer after bulk ring-expansion metathesis polymerization of cyclopentene. It is enabled by introducing silica-supported ruthenium catalysts and newly designed glassware. Different depolymerization kinetics of the cyclic polymer from its linear analogue are also discussed. This process minimizes manual labour, maximizes the security of vulnerable catalysts and guarantees the purity of cyclic polymers, thereby showcasing a prototype of a scalable access to cyclic polymers with increased turnovers (≥415,000) of precious catalysts.

DOI: 10.1038/s41557-022-01034-8

Source: https://www.nature.com/articles/s41557-022-01034-8