Polymerization of ethylene to branched poly(ethylene)s using ansa-η5-monofluorenyl cyclohexanolato zirconium(IV) complex/methylaluminoxane
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ansa-η5-Monofluorenyl cyclohexanolato zirconium complex 3 was shown to be active for the polymerization of ethylene when activated with methylaluminoxane (MAO) at 5 bar. Up to a polymerization temperature of 40 °C, 3/MAO resulted in linear poly(ethylene)s with saturated chain ends. However, at polymerization temperatures of 60, 80, and 100 °C, a mixture of branched poly(ethylene)s, linear α-olefins and long chain alkanes was obtained. The poly(ethylene)s produced at 80 and 100 °C exhibited a bimodal molecular weight distribution indicative of multiple active species. Very high molecular weight (Mv > 5 × 105) linear poly(ethylene)s were obtained using 3/MAO at 25 °C.
Keywordsansa-Monofluorenyl complex Methyl aluminoxane Ethylene polymerization Branched poly(ethylene)s Bimodal MWD
AR thanks the Council for Scientific and Industrial Research, New Delhi, India for Junior and Senior Research Fellowships.
- 1.Kaminsky W, Arndt M (1997) Metallocenes for polymer catalysis. Adv Polym Sci 127:144–187Google Scholar
- 2.Bochmann M (1996) Cationic group 4 metallocene complexes and their role in polymerization catalysis: the chemistry of well-defined Ziegler catalysts. J Chem Soc; Dalton Trans 255–270Google Scholar
- 5.Stevens JC, Timmers FJ, Wilson DR, Schmidt GF, Nickias PN, Rosen RK, Knight GW, Lai S-Y (1991) Constrained geometry addition polymerization catalysts, processes for their preparation, precursors therefore, methods of use and novel polymers formed therewith. European Patent 0416815, Dow Chemical CompanyGoogle Scholar
- 6.Stevens JC, Neithamer DR (1991) Metal complex compounds, process for preparation and method of use. European Patent 0418044, Dow Chemical CompanyGoogle Scholar
- 7.Canich JAM (1991) Process for producing crystalline poly α-olefins with a monocyclopentadienyl transition metal catalyst system. US Patent 5026798, ExxonGoogle Scholar
- 8.Canich JAM, Licciardi GF (1991) Mono Cp heteroatom group IVB transition metal complexes with MAO: supported catalyst for olefin polymerization. US Patent 5057475, ExxonGoogle Scholar
- 9.Canich JAM (1991) Olefin polymerization catalysts. European Patent 0420436, ExxonGoogle Scholar
- 14.Skeril R, Sindelar P, Salajka Z, Varga V, Cisarova I, Pinkas J, Horacek M, Mach K (2004) Copolymerization of ethene with styrene using CGC catalysts: the effect of the cyclopentadienyl ligand substitution on the catalyst activity and copolymer structure. J Mol Catal A 224:97–103CrossRefGoogle Scholar
- 15.Martinez S, Exposito MT, Ramos J, Cruz V, Martinez MC, Lopez M, Munoz-Escalona A, Martinez-Salazar J (2005) An experimental and computational evaluation of ethylene/styrene copolymerization with a homogeneous single-site titanium(IV)-constrained geometry catalyst. J Polym Sci A 43:711–725CrossRefGoogle Scholar
- 20.Senda T, Hanaoka H, Nakahara S, Oda Y, Tsurugi H, Mashima T (2010) Rational design of silicon-bridged fluorenyl-phenoxy group 4 metal complexes as catalysts for producing high molecular weight copolymers of ethylene and 1-hexene at elevated temperature. Macromolecules 43:2299–2306CrossRefGoogle Scholar