Process of polymerization of propylene

A Ziegler-Natta pro-catalyst composition for the polymerization of propylene to produce polypropylene with reduced polymer-fines, comprising a reaction product of (i) at least one titanium compound of the molecular formula TiXn(OR1)4-n, wherein n is an integer from 0 to 4, X is halogen, R1 is independently selected from the group consisting of C1 to C10 alkyl group;

• (ii) at least one magnesium containing precursor of molecular formula Mg(OR2)(OR3), wherein R2 and R3 are identical or different, and independently selected from the group consisting of C1 to C10 alkyl groups, C1 to C6 aryl group and C1 to C10 alkylaryl group;
• and (iii) at least one internal electron donor selected from the group of compounds consisting of dicarboxylic acid ester, monocarboxylic acid ester, diethers, silyl esters, amides, carbonates, and succinates;
• said pro-catalyst composition containing iron ranging between about 50 ppm and 100 ppm.