Synthesis of branched polyethylene by ethylene homopolymerization using titanium catalysts that contain a bridged bis(phenolate) ligand

The synthesis of branched polyethylene from single ethylene feed has been achieved by using a methylaluminoxane-activated titanium complex bearing a tetradentate bis(phenolate) ligand with a 1,4-dithiabutanediyl bridge 1. This catalyst produces polyethylene with activities up to 6200 kg polymer/mol h bar. As evidenced by 13C NMR analyses, the polyethylenes contain ethyl, n-butyl, and long-chain (n-hexyl or longer) branches in a range variable from 0.2 to 2.0%, depending on the experimental parameters. NMR and gas chromatography/mass spectrometry analyses suggest that such polymer microstructure arises from the in situ production of oligomers and their subsequent incorporation into the growing polyethylene chain. The broad molecular weight distribution of these polyethylenes indicates the presence of different catalytic species. The related catalyst system 2 bearing a longer 1,5-dithiapentanediyl bridge produces linear polyethylene with moderate activity. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2815–2822, 2004

[1]  R. Mülhaupt,et al.  Ancillary ligand effect on single-site styrene polymerization: isospecificity of group 4 metal bis(phenolate) catalysts. , 2003, Journal of the American Chemical Society.

[2]  V. C. Gibson,et al.  Advances in non-metallocene olefin polymerization catalysis. , 2003, Chemical reviews.

[3]  G. Bazan,et al.  Triple tandem catalyst mixtures for the synthesis of polyethylenes with varying structures. , 2002, Journal of the American Chemical Society.

[4]  C. Tedesco,et al.  Branching Formation in the Ethylene Polymerization with Meso Ansa Metallocene-Based Catalysts , 2002 .

[5]  Z. Guan.  Control of polymer topology by chain-walking catalysts. , 2002, Chemistry.

[6]  G. Bazan,et al.  NMR Study of Branched Polyethylenes Obtained with Combined Fe and Zr Catalysts , 2002 .

[7]  G. Bazan,et al.  Synthesis of Branched Polyethylene from Ethylene by Tandem Action of Iron and Zirconium Single Site Catalysts , 2001 .

[8]  M. Brookhart,et al.  Late-metal catalysts for ethylene homo- and copolymerization. , 2000, Chemical reviews.

[9]  G. Bazan,et al.  Synthesis of Butene−Ethylene and Hexene−Butene−Ethylene Copolymers from Ethylene via Tandem Action of Well-Defined Homogeneous Catalysts , 2000 .

[10]  L. Izzo,et al.  Branched Polyethylene by Ethylene Homopolymerization with meso-Zirconocene Catalyst , 1999 .

[11]  B. Weckhuysen,et al.  Olefin polymerization over supported chromium oxide catalysts , 1999 .

[12]  D. Pappalardo,et al.  Branched Polyethylene Produced by a Half-Titanocene Catalyst , 1999 .

[13]  P. Rinaldi,et al.  Resolution of Signals from Long-Chain Branching in Polyethylene by 13C NMR at 188.6 MHz , 1999 .

[14]  McLain,et al.  Chain walking: A new strategy to control polymer topology , 1999, Science.

[15]  R. F. Souza,et al.  13C NMR Determination of the Composition of Linear Low-Density Polyethylene Obtained with [η3-Methallyl-nickel-diimine]PF6 Complex , 1999 .

[16]  T. J. Pullukat,et al.  Silica-Based Ziegler–Natta Catalysts: A Patent Review , 1999 .

[17]  R. Waymouth,et al.  Group 4 ansa-Cyclopentadienyl-Amido Catalysts for Olefin Polymerization. , 1998, Chemical reviews.

[18]  G. Bazan,et al.  Synthesis of Branched Polyolefins Using a Combination of Homogeneous Metallocene Mimics , 1998 .

[19]  R. Blom,et al.  N.m.r. characterization of polyethylene with emphasis on internal consistency of peak intensities and estimation of uncertainties in derived branch distribution numbers , 1997 .

[20]  David Fischer,et al.  Stereospecific Olefin Polymerization with Chiral Metallocene Catalysts , 1995 .

[21]  Maurice Brookhart,et al.  New Pd(II)- and Ni(II)-Based Catalysts for Polymerization of Ethylene and .alpha.-Olefins , 1995 .

[22]  T. Usami,et al.  Fine-branching structure in high-pressure, low-density polyethylenes by 50.10-MHz carbon-13 NMR analysis , 1984 .