Group 4 permethylindenyl complexes for slurry-phase polymerisation of ethylene

Abstract

A series of ten well-defined group 4 ansa-bridged permethylindenyl complexes have been prepared, fully characterised and supported on inorganic solid supports. These catalysts were investigated in the slurry-phase polymerisation of ethylene. A range of inorganic solid supports have been utilised; solid polymethylaluminoxane (sMAO), MAO modified layered double hydroxide (LDHMAO) and MAO modified silica (SSMAO). The sMAO supported catalytic systems exhibit some of the highest slurry-phase polymerisation activities reported in literature with activities reaching 9509 kg_PE mol_M⁻¹ h⁻¹ bar⁻¹ for ^Me2SB(Cp^Me,I*)ZrMe₂ at 80 °C after 5 minutes of polymerisation; 34% more active than an industrial standard under similar conditions. These systems produce polyethylenes with low molecular weights, M_w, reaching as low as 46 kg mol⁻¹ for E-^Me2SB(Cp^nBu,I*)ZrCl₂ at 90 °C after 30 minutes of polymerisation with a uniform, mono-disperse “popcorn” morphology. The sMAO supported systems show much higher catalytic activities and much more industrially desirable polyethylene morphology than the same complexes supported on LDHMAO and SSMAO.