The role of additives for the improvement of δ‐TiCl₃ catalyst performance

Abstract

The influence of ethylaluminium compounds (AlEt, and AICIEt,) modified by 2,6-ditert-butyl-4-methylphenol (BHT), tributylamine (TBA) and triphenylphosphine (TPP) on the polymerization of propene was investigated using catalysts based on TiCl, modified by internal Lewis bases. W o catalysts were employed in this study, one (Cat. A) was prepared by the reduction of TiCl, complexed with dibutyl ether (DBE)mole ratio DBE/TiCI, = 0,67with AlClEt, and the other one (Cat. B) was prepared in the same way, but a second internal base (ethyl benzoate (EB)) was added in a mole ratio EB/TiCI, = 0,M. Activity and stereospecificity of the catalyst systems were strongly affected by these modified cocatalysts. The role of the modifiers is discussed.