Investigating the Nature of the Active Species in Bis(imino)pyridine Cobalt Ethylene Polymerization Catalysts
摘要:
The activation of bis(imino)pyridine cobalt-based catalysts of ethylene polymerization with methylalumoxane (MAO), AlMe3, and AlMe3/[CPh3][B(C6F5)(4)] has been studied by H-1, H-2, and F-19 NMR and EPR spectroscopy. The nature of the active sites of polymerization is discussed. The polymerization kinetics and the polymer properties for the different catalyst/activator systems were correlated with spectroscopic data.
一系列新颖的双(亚氨基)吡啶钴(II)氯化物LCoCl 2具有在苯胺部分带有一个或多个吸电子取代基(F,Cl,Br,CF 3)的双(亚氨基)吡啶配体准备和表征。在甲基铝氧烷(MAO)的存在下,这些配合物表现出高的乙烯低聚和聚合活性(高达1.8·10 7 g产品∙(mol Co)-1 h -1 bar -1),提供的产品范围为1-丁烯和Z,E -2-丁烯至严格线性低分子量(M n 〜300…700)聚乙烯。讨论了反应结果对配体结构的依赖性。