Titanocene-based catalyst system

A catalyst system obtained by a process comprising:

• contacting:
• (i) a support of a partially dealcoholated adduct of formula
• MgT2wR′OH, wherein
• T is chlorine, bromine, or iodine;
• R′ is a linear or branched C1-C10 alkyl radical;
• and
• w is a non-integer number ranging from 3 to 0.1;
• with
• (ii) an organo-aluminium compound of formula HeA1U3-e or HeA12U6-e, wherein
• U, same or different, are hydrogen, halogen, or hydrocarbon radicals comprising from 1 to 20 carbon atoms, and optionally comprise at least one silicon or germanium atom;
• with the proviso that at least one U is different from halogen;
• and
• e is a non-integer number ranging from 0 to 1;
• to obtain an adduct of formula (I)
• MgT2.yAlQj(OR″)3-j (I)
• wherein
• y ranges from 1.00 to 0.05;
• Q, same or different, are hydrocarbon radicals comprising from 1 to 20 carbon atoms, and optionally comprise at least one silicon or germanium atom;
• R″ is a linear or branched C1-C10 alkyl radical;
• and j is a non-integer number ranging from 0.01 to 3.00;
• and
• contacting the adduct of formula (I) with at least one metallocene compound comprising titanium as a central metal and at least one ligand comprising a cyclopentadienyl skeleton;
• with the proviso that the metallocene compound has not been previously treated with an organo-aluminium compound of formula HeAlU3-e or HeAl2U6-e, or an alumoxane.