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

A new family of zirconocene complexes of the type ( 3-R Ind # ) 2 ZrX 2 (where Ind # = C 6 Me 5 H and R = Me, Et and Ph) have been synthesised and fully characterised. Six new crystal structures have been reported ( meso -( 3-Et Ind # ) 2 ZrBr 2 , rac -( 3-Et Ind # ) 2 ZrCl 2 , rac -( 3-Et Ind # ) 2 Zr(CH 2 Ph) 2 , meso -( 3-Et Ind # ) 2 Zr(CH 2 Ph) 2 , meso -( 3-Me Ind # ) 2 ZrBr 2 and meso -( 3-Me Ind # ) 2 Zr(CH 2 Ph) 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-Et Ind # ) 2 Zr(CH 2 Ph) 2, sMAO- meso -( 3-Et Ind # ) 2 ZrCl 2 and sMAO- meso -( 3-Et Ind # ) 2 ZrBr 2 (activities of 657, 561, and 452 kg PE mol M -1 h -1 bar -1 , respectively). sMAO- meso -( 3-Et Ind # ) 2 ZrBr 2 produces HDPE with the highest molecular weight, followed by sMAO- meso -( 3-Et Ind # ) 2 ZrCl 2 and sMAO- meso -( 3-Et Ind # ) 2 Zr(CH 2 Ph) 2 ( M w of 503, 406, and 345 kg mol -1 , respectively, at 50 °C). sMAO- meso -( 3-Me Ind # ) 2 ZrBr 2 produced HDPE with almost identical molecular weights to sMAO- meso -( 3-Et Ind # ) 2 ZrCl 2 (395 kg mol -1 at 50 °C).