Procatalyst for polymerization of olefins

A process for preparing a procatalyst for preparing a catalyst composition for olefin polymerization, said process comprising the steps of:

• i) contacting a Grignard reagent comprising R4zMgX42-z and an alkyl magnesium compound MgR4′2 with an alkoxy- or aryloxy-containing silane compound to give a first intermediate reaction product, being a solid Mg(OR1)xX12-x, wherein:
• R4 and R4′ are the same as R1 being a linear, branched or cyclic hydrocarbyl group independently selected from alkyl, alkenyl, aryl, aralkyl, alkoxycarbonyl or alkylaryl groups, and one or more combinations thereof;
• wherein said hydrocarbyl group is substituted or unsubstituted, and optionally contains one or more heteroatoms;
• X4 and X1 are each independently selected from the group of fluoride (F—), chloride (Cl—), bromide (Br—) or iodide (I—);
• and
• z is in a range of larger than 0 and smaller than 2, being 0<z<2;
• ib) precipitating the solid Mg(OR1)xX12-x obtained in step i) by contacting it with an tetrahalogensilane, SiX4′4, wherein X4′ is each independently selected from the group consisting of fluoride (F—), chloride (Cl—), bromide (Br—) or iodide (I—), to obtain a solid support;
• ii) optionally contacting the solid support obtained in step ib) with at least one activating compound selected from the group formed by activating electron donors and metal alkoxide compounds of formula M1(OR2)v-w(OR3)w or M2(OR2)v-w(R3)w, to obtain a second intermediate reaction product;
• wherein:
• M1 is a metal selected from the group consisting of Ti, Zr, Hf, Al or Si;
• M2 is a metal being Si;
• v is the valency of M1 or M2;
• R2 and R3 are each a linear, branched or cyclic hydrocarbyl group independently selected from alkyl, alkenyl, aryl, aralkyl, alkoxycarbonyl or alkylaryl groups, and one or more combinations thereof;
• wherein said hydrocarbyl group is substituted or unsubstituted, and optionally contains one or more heteroatoms,
• iii) contacting the first or second intermediate reaction product obtained in step ib) or ii) respectively, with a halogen-containing titanium compound and either an activator or an internal electron donor to obtain a third intermediate reaction product;
• iv) optionally modifying the third intermediate reaction product obtained in step iii) with a modifier having the formula MX3, wherein M is a metal selected from the Group 13 metals and transition metals of the IUPAC periodic table of elements, and wherein X is a halide, to yield a modified intermediate reaction product;
• and
• v) contacting said third intermediate reaction product obtained in step iii) or said modified intermediate reaction product obtained in step iv) with a halogen-containing titanium compound and in the case that in step iii) an activator was used an internal donor to obtain the procatalyst.