Department of Chemistry, Imperial College London, London, SW7 2AZ, UK.
J Am Chem Soc. 2012 Sep 26;134(38):15676-9. doi: 10.1021/ja307096m. Epub 2012 Sep 12.
The synthesis and characterization of three highly active dimagnesium catalysts for the copolymerization of cyclohexene oxide and carbon dioxide, active under just 1 atm of carbon dioxide pressure, are reported. The catalysts have turnover numbers up to 6000 and turnover frequencies of up to 750 h(-1). These values are, respectively, 75 and 20 times higher than those of the other three known magnesium catalysts. Furthermore, the catalysts operate at 1/500th the loading of the best reported magnesium catalyst. The catalyst selectivities are excellent, yielding polymers with 99% carbonate repeat units and >99% selectivity for copolymer. Using a dimagnesium bis(trifluoroacetate) catalyst, and water as a renewable chain transfer reagent, poly(cyclohexene carbonate) polyols are synthesized with high selectivity.
报道了三种高效二镁催化剂的合成与表征，可在 1 大气压二氧化碳压力下引发环氧化环己烯与二氧化碳共聚。这些催化剂的周转数高达 6000，转化频率高达 750 h(-1)。与其他三种已知的镁催化剂相比，这两个数值分别提高了 75 倍和 20 倍。此外，这些催化剂的负载量仅为报道的最佳镁催化剂的 1/500。催化剂的选择性极好，生成的聚合物中碳酸酯重复单元的比例达到 99%，且共聚产物的选择性 >99%。使用二镁双（三氟乙酸酯）催化剂，并以水作为可再生的链转移试剂，可高选择性地合成聚（环氧化环己烯碳酸酯）多元醇。
