Song Chuang, Yang Dian, Wang Chaoqun, Tang Zhenxin, Long Yingyun, Zhang Yuxing, Jian Zhongbao
State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Renmin Street 5625, Changchun, 130022, China.
School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei, 230026, China.
Angew Chem Int Ed Engl. 2024 Oct 24;63(44):e202410885. doi: 10.1002/anie.202410885. Epub 2024 Sep 20.
To access degradable polyolefin plastic, non-alternating copolymerization of ethylene (E) and carbon monoxide (CO) for producing polyethylene (PE) with in-chain ketones is particularly appealing; however, it still presents significant challenges such as molecular weight modulation (hydrogen response) and chain endgroup control (functional terminal). In this study, we achieved hydrogen-controlled E/CO non-alternating copolymerization using late transition metal catalysts. This process results in linear PEs containing the desired non-alternating in-chain keto groups (1.0-9.3 mol %) and with tunable molecular weights ranging from 43 to 195 kDa. In this reaction, H serves as a chain transfer agent, modulating the polymer's molecular weight, forming unique aldehyde endgroups and eliminating usual olefinic endgroups; CO undergoes non-alternating insertion into the PE chain, resulting in a strictly non-alternating structure (>99 %) for the keto-PE. The dispersed incorporation of in-chain keto groups retains bulk properties of PE and makes PE susceptible to photodegradation, which produces significantly lower molecular weight polymers and oligomers with unambiguous vinyl and acetyl terminals.
为了获得可降解聚烯烃塑料，通过乙烯（E）与一氧化碳（CO）的非交替共聚来制备含链内酮的聚乙烯（PE）极具吸引力；然而，它仍然面临着诸如分子量调控（氢响应）和链端基控制（官能团末端）等重大挑战。在本研究中，我们使用后过渡金属催化剂实现了氢控制的E/CO非交替共聚。该过程产生了含有所需非交替链内酮基（1.0 - 9.3 mol %）且分子量可调范围为43至195 kDa的线性PE。在该反应中，H作为链转移剂，调节聚合物的分子量，形成独特的醛端基并消除常见的烯烃端基；CO以非交替方式插入PE链中，使得酮基PE具有严格的非交替结构（>99 %）。链内酮基的分散引入保留了PE的本体性质，并使PE易于光降解，从而产生分子量显著更低的聚合物和具有明确乙烯基和乙酰基末端的低聚物。
