Mulhearn William D, Register Richard A
Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States.
ACS Macro Lett. 2017 Feb 21;6(2):112-116. doi: 10.1021/acsmacrolett.6b00969. Epub 2017 Jan 20.
Methods for the preparation of narrow-distribution ROMP polycyclopentene are developed to suppress the rate of acyclic metathesis: reaction between the active metal-carbene chain end and an acyclic olefin in the reaction medium. In particular, we investigate interchain metathesis, which generates linear polymers with "scrambled" chain lengths, and we demonstrate the formation of ring polymers by intrachain backbiting and quantify their content in the reaction product. By controlling the relative rates of propagation versus these side reactions, we prepare ROMP polycyclopentene with low dispersity to substantially higher molecular weights than have been reported previously. Polymerization kinetics are quantitatively described by a kinetic model, which accounts for the reversible binding of added trimethylphosphine to the active chain end.
为抑制开环易位反应速率（即反应介质中活性金属卡宾链端与开环烯烃之间的反应），开发了制备窄分布开环易位聚合聚环戊烯的方法。具体而言，我们研究了链间易位反应（该反应生成链长“混乱”的线性聚合物），并证明了通过链内回咬形成环状聚合物，还对其在反应产物中的含量进行了定量分析。通过控制增长速率与这些副反应的相对速率，我们制备出了低分散度的开环易位聚合聚环戊烯，其分子量比之前报道的要高得多。聚合动力学由一个动力学模型进行定量描述，该模型考虑了添加的三甲基膦与活性链端的可逆结合。
