Supported bis(peralkylindenyl)metallocene catalysts for slurry phase ethylene polymerisation

Synthesis of zirconocene complexes and their use in slurry-phase polymerisation of ethylene

A new family of zirconocene complexes of the type (^3-RInd^#)₂ZrX₂ (where Ind^# = C₆Me₅H and R = Me, Et and Ph) have been synthesised and fully characterised. Six new crystal structures have been reported (meso-(^3-EtInd^#)₂ZrBr₂, rac-(^3-EtInd^#)₂ZrCl₂, rac-(^3-EtInd^#)₂Zr(CH₂Ph)₂, meso-(^3-EtInd^#)₂Zr(CH₂Ph)₂, meso-(^3-MeInd^#)₂ZrBr₂ and meso-(^3-MeInd^#)₂Zr(CH₂Ph)₂). The complexes were studied for slurry-phase ethylene polymerisation when immobilised on solid polymethylaluminoxane (sMAO). Variation in the initiation group was found to have greater influence over polymerisation activity for meso-catalysts than rac-catalysts, with meso-alkyl catalysts showing higher polymerisation activities than meso-halide. Below 70 °C, polymerisation activity follows the order sMAO-meso-(^3-EtInd^#)₂Zr(CH₂Ph)_2, sMAO-meso-(^3-EtInd^#)₂ZrCl₂ and sMAO-meso-(^3-EtInd^#)₂ZrBr₂ (activities of 657, 561, and 452 kg_PE mol_M⁻¹ h⁻¹ bar⁻¹, respectively). sMAO-meso-(^3-EtInd^#)₂ZrBr₂ produces HDPE with the highest molecular weight, followed by sMAO-meso-(^3-EtInd^#)₂ZrCl₂ and sMAO-meso-(^3-EtInd^#)₂Zr(CH₂Ph)₂ (M_w of 503, 406, and 345 kg mol⁻¹, respectively, at 50 °C). sMAO-meso-(^3-MeInd^#)₂ZrBr₂ produced HDPE with almost identical molecular weights to sMAO-meso-(^3-EtInd^#)₂ZrCl₂ (395 kg mol⁻¹ at 50 °C).

A new family of zirconocene complexes of the type (^3-RInd^#)₂ZrX₂ (where Ind^# = C₆Me₅H and R = Me, Et and Ph) have been synthesised and fully characterised.

Group 4 permethylindenyl complexes for the polymerisation of l-, d- and rac-lactide monomers

A series of well-defined group 4 permethylindenyl complexes have been prepared and fully characterised by NMR spectroscopy and X-ray crystallography. Me2SB(Cp,I*)ZrCl2 ({(η5-C9Me6)Me2Si(η5-C5H4)}ZrCl2; 1), Me2SB(CpMe,I*)ZrCl2 ({(η5-C9Me6)Me2Si(η5-C5H3Me)}ZrCl2; 2), Me2SB(Cp,I*)HfCl2 (3) and Z-Me2SB(Cp,I*)ZrCl(O-2,6-Me-C6H3) (4) were investigated as initiators for the ring-opening polymerisation (ROP) of l-, d- and rac-lactide monomers in the presence of benzyl alcohol. 1-4 displayed second order dependence on monomer concentration and produced isotactic and heterotactic (Pr = 0.81) polylactides for the polymerisation of l-, d- and rac-lactide respectively. The effects of temperature, catalyst concentration, co-initiator concentration, solvent and scale were studied. At 80 °C, with two equivalents of benzyl alcohol, 4 was the most active initiator for the ROP of l-, d- and rac-lactide (kobs = 6.39, 6.38 and 5.89 M-1 h-1 respectively). The polylactides were characterised by NMR spectroscopy, GPC and MALDI-TOF mass spectrometry.

Group 4 permethylindenyl complexes for slurry-phase polymerisation of ethylene

Supported group 4 permethylindenyl based catalysts displayed extremely high ethylene polymerisation activity affording popcorn shaped low molecular weights polyethylenes.

Popcorn-shaped polyethylene synthesised using highly active supported permethylindenyl metallocene catalyst systems

Unsymmetrical permethylindenyl bent metallocene complexes have been synthesised and reacted with inorganic solid supports to afford catalysts for the slurry phase polymerisation of ethylene. Those supported on solid polymethylaluminoxane were both highly active catalysts and afforded polymers with a desirable, low aggregation, "popcorn" morphology.