FIELD: chemistry.
SUBSTANCE: invention relates to olefin polymerisation catalysts. Disclosed is a method of halogenating an olefin polymerisation procatalyst precursor which involves halogenating a procatalyst precursor in the presence of a substituted aromatic phenylene diether at temperature ranging from about 90°C to less than or equal to about 100°C. The aromatic phenylene diether has the structure 
,
wherein groups R1-R14 are identical or different, each group from R1-R14 is selected from a group consisting of a hydrogen atom, halogen, a hydrocarbon group containing 1-20 carbon atoms and an alkoxy group containing 1-20 carbon atoms and combinations thereof, and where at least one of the groups R1-R14 is not hydrogen. The Ziegler-Natta procatalyst composition has selectivity index less than 2.5 and has a magnesium component, a titanium component and a substituted aromatic phenylene diether. Also disclosed is a procatalyst composition obtained using said method.
EFFECT: present procatalyst composition increases catalyst selectivity and increases apparent density of the formed polymer.
8 cl, 6 tbl, 10 ex
