Bielawski Christopher W, Benitez Diego, Grubbs Robert H
Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.
J Am Chem Soc. 2003 Jul 16;125(28):8424-5. doi: 10.1021/ja034524l.
The synthesis of cyclic polybutadienes using ring-opening metathesis polymerization (ROMP) was accomplished. A cyclic Ru alkylidene catalyst, where a terminal ligand was covalently linked to the Ru alkylidene, was used to polymerize either 1,5-cyclooctadiene (COD) or 1,5,9-trans-cis-trans-cyclododecatriene (CDT). Trace amounts of an acyclic impurity, 4-vinylcyclohexene, found in the COD led to samples which were contaminated with linear polymer. In contrast, CDT, which was free of the impurity, afforded pure cyclic polymer. These results provide a convenient method for discerning samples of pure cyclic polymer from those which contain trace to large amounts of linear polymer. Furthermore, they emphasize the need to use monomers that are free of acyclic impurities when preparing cyclic polymers using ROMP.
通过开环易位聚合（ROMP）实现了环状聚丁二烯的合成。使用一种环状钌亚烷基催化剂（其中末端配体与钌亚烷基共价连接）来聚合1,5-环辛二烯（COD）或1,5,9-反-顺-反-环十二碳三烯（CDT）。在COD中发现的痕量无环杂质4-乙烯基环己烯导致样品被线性聚合物污染。相比之下，不含该杂质的CDT得到了纯环状聚合物。这些结果提供了一种方便的方法，用于区分纯环状聚合物样品与含有痕量至大量线性聚合物的样品。此外，它们强调了在使用ROMP制备环状聚合物时使用不含无环杂质的单体的必要性。
