Olefin polymerization at bis (pentamethylcyclopentadienyl) zirconium and-hafnium centers: chain-transfer mechanisms

L Resconi, F Piemontesi, G Franciscono…

文献索引：Resconi, Luigi; Piemontesi, Fabrizio; Franciscono, Giuseppe; Abis, Luigi; Fiorani, Tiziana Journal of the American Chemical Society, 1992 , vol. 114, # 3 p. 1025 - 1032

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被引用次数: 304

摘要

Abstract: Chain transfer via@-CH3 elimination by a homogeneous bimetallic Ziegler-Natta propylene polymerization catalyst is reported. Propylene is converted by Cpt2MC12/MA0 catalysts (Cp*= pentamethylcyclopentadienyl; M= Zr, Hf; MA 0= methylalumoxane) to atactic propylene oligomers and low polymers. GC-MS and'H and I3C NMR analyses of the oligomers obtained at 50 OC (P,= 4.5 for Zr, 3.4 for Hf) show these products to be mainly ...