Abstract:
Described are catalyst systems having aluminium alkyl complexes of the formula (I) described herein applied to magnesium chloride, SiO2 or SiO2 in combination with MgCl2 as support in the presence of titanium halides or vanadium halides and internal and, if desired, external donors act both as cocatalysts and as stereoselectivity promoters in heterogeneous polymerizations of &agr;-olefins. Also described are polymerization methods using these catalyst systems.
Abstract:
The invention relates to the use of nitrogenous aluminium organyl complexes of general formula (I) as co-catalysts in heterogeneous polymerisation reactions of propene. In said formula: R, R′, R1 and R1′ independently of one another represent branched or unbranched C1-C7 alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl or alkynyl; R2 represents unsubstituted, monoalkylated or polyalkylated and/or monofluorinated or polyfluorinated aromatic hydrocarbons from group (II); R3 and R4 independently of one another represent CH2, CF2 oder C(R1)2; m stands for 0, 1 or 2; n stands for 0, 1 or 2; o stands for 0 or 1, all independently of one another. Said systems exhibit improved characteristics in terms of activity and stereoselectivity in comparison to conventional co-catalysts such as AlEt3 and can act simultaneously as co-catalysts and stereoselectivity promoters