Grubbs third‐generation catalyst (G3) in ring‐opening metathesis polymerization (ROMP) shows unique kinetic behaviors and ligand‐addition enabled metathesis activity regulation, while several kinetic features have not been fully revealed. In this work, a thorough kinetic analysis of G3‐catalyzed ROMP, for the first time, is carried out via method‐of‐moments‐based numerical simulation and experiments. A generalized kinetic model considering possible metathesis reactions is developed and a stable‐deviation‐analysis strategy is proposed to estimate the rate coefficient for cyclic monomer propagation. Simulation results confirm that the number of active sites for propagation is independent of the G3 concentration, resulting in the zeroth‐order kinetic dependence. Adding external pyridine ligand accelerates the consumption of G3 through a coordination competition, and a positive relation between external ligand concentration and the rate for reaching the steady‐state condition is disclosed. The interchain metathesis reaction increases molar mass dispersity by increasing the weight‐average molar mass, which can be effectively mitigated by adding a strongly coordinating external ligand. Analysis of ring‐chain competition in intrachain backbiting suggests that increasing the initial concentration of reactants can enhance the selectivity for producing linear polymers. This study provides a comprehensive understanding of the mechanism‐governed ROMP kinetic behaviors and aids in the precision synthesis of cyclic olefin polymers.

中文翻译：

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G3 催化的 ROMP 的机理引导动力学分析用于环状烯烃聚合物的精确合成


开环复分解聚合 （ROMP） 中的 Grubbs 第三代催化剂 （G3） 显示出独特的动力学行为和配体加成启用的复分解活性调节，而一些动力学特征尚未完全揭示。在这项工作中，首次通过基于矩法的数值模拟和实验对 G3 催化的 ROMP 进行了彻底的动力学分析。开发了一种考虑可能的复分解反应的广义动力学模型，并提出了一种稳定偏差分析策略来估计循环单体传播的速率系数。模拟结果证实，传播的活性位点数量与 G3 浓度无关，导致零级动力学依赖性。通过配位竞争添加外部吡啶配体加速了 G3 的消耗，并且揭示了外部配体浓度与达到稳态条件的速率之间的正相关关系。链间复分解反应通过增加重均摩尔质量来增加摩尔质量分散性，这可以通过添加强配位的外部配体来有效缓解。对链内反咬合中环链竞争的分析表明，增加反应物的初始浓度可以提高生产线性聚合物的选择性。本研究提供了对机制控制的 ROMP 动力学行为的全面理解，并有助于环烯烃聚合物的精确合成。