Development of novel MgCl2 supported catalyst with trivalent titanocene complex of CP2TiCl2AlCl2 for propylene polymerization

Three kinds of MgCl₂‐supported trivalent titanocene catalyst (Cat. 1: Cp₂TiCl₂AlCl₂/MgCl₂, Cat. 2: CpCp*TiCl/MgCl₂, Cat. 3: Cp₂TiCl/MgCl₂) were prepared and tested for propylene polymerization. It was found that Cat. 1, combined with ordinary alkylaluminum as cocatalyst, produced PP containing 31.8 wt % of isotactic PP in fairly good yield. On the other hand, Cats. 2 and 3 hardly showed any activity. The effects of diisopropyldimethoxysilane (DIPDMS) on isospecificity of the Cat. 1 also were investigated. The isotactic index (I.I.) of PP was improved drastically by the addition of DIPDMS as external donor and reached the value as high as 98.4%, even in the absence of any internal donors. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3355–3359, 2000