Synthesis of a dinuclear ansa-zirconocene catalyst having a biphenyl bridge and application to ethene polymerization

• Published in: Journal of molecular catalysis. A, Chemical Chemical, 1998-02, Vol.128 (1), p.273-278
• Main Authors: Soga, Kazuo, Ban, Hoang The, Uozumi, Toshiya
• Format: Article
• Language: English
• Subjects: Biphenyl bridge; Dinuclear ansa-zirconocene catalyst; Ethene polymerization
• ISSN: 1381-1169; 1873-314X
• DOI: 10.1016/S1381-1169(97)00180-5

A novel dinuclear ansa-zirconocene catalyst ( μ-C 12H 8{[SiPh(Ind) 2]ZrCl 2} 2) ( I) was prepared by a Wurtz coupling reaction between two equivalent of bisindenylphenylchlorosilane and one equivalent of 4,4′-dibromobiphenyl in THF at reflux temperature for 12 h, followed by a successive reaction with ZrCl 4·2THF in THF at −78°C. Polymerization of ethene was conducted in a 300 cm 3 glass reactor equipped with a stirrer at 40, 60, 80 and 100°C using MAO or Ph 3C[B(C 6F 5) 4] as cocatalyst and toluene as the solvent. The catalyst ( I) gave linear polyethene with a broader molecular mass distribution (MMD) in a much higher yield as compared to the corresponding mononuclear catalyst derived from [Ph 2Si(Ind) 2]ZrCl 2 ( II). The apparent activity increased monotonously from 40°C up to 100°C. The replacement of MAO with Ph 3C[B(C 6F 5) 4] gave polyethene with a higher molecular weight.