Syndiospecific polymerization of propene under different processes with different bridged [(RPh)2C(Cp)(2,7-tertBuFlu)]ZrCl2 metallocene catalysts

The synthesis of syndiotactic polypropene was achieved by using new CS-sym. ansa-metallocene catalysts of the type [Ph'2C(Cp)(2,7-tertBu2Flu)]ZrCl2 (Ph'2 = Ph2, (4-MePh)2, 3,4'-Me2Ph2, (4-OMePh)2). Using these catalysts, the influence of the substitution pattern of the bridge on the polymn. performance can be studied and highly syndiotactic polypropene (rrrr>99%) with high molar masses (Mh>106 g/mol) and high melting temps. (up to 153 DegC) was obtained. Propene was polymd. at different temps. under four sets of conditions: in toluene soln., bulk, toluene slurry, and gas phase with NaCl as stirred bed material. Methylaluminoxane (MAO) and methylaluminoxane supported on silica gel (MAO/SiO2) were used as cocatalyst, resp. In order to est. the influence of the process on the single site properties of the catalysts, comparisons were made between polymer properties, i.e. microstructure, melting temp., molar mass, and polymer morphol., thus allowing the effect of the support on the catalyst to be obsd