Catalyst for the polymerization of propylene and its use

A catalyst for the polymerization of propylene comprising:

• (A) a solid catalyst component prepared by dissolving a halide of magnesium in a solvent system consisting of an organic epoxy compound, an organic phosphorus compound and a first inert diluent to form a homogenous solution;
• mixing the homogenous solution with a first halide of titanium to form a mixture;
• precipitating a solid from the mixture in the presence of an auxiliary precipitant;
• treating the solid with a polycarboxylic acid ester to load the ester on the solid;
• and treating the ester loaded solid with a second halide of titanium and a second inert diluent;
• wherein said auxiliary precipitant being selected from the group consisting of organic anhydrides, organic acid, ethers and ketones;
• and wherein based per mole of the halide of magnesium, the amount of the organic epoxy compounds is from 0.2 to 5 moles, and the molar ratio of the organic epoxy to the organic phosphorus compounds is from 0.5 to 1.6;
• (B) an organic aluminum compound having the formula AlRnX3-n wherein each R is independently hydrogen or hydrocarbyl group having 1-20 carbon atoms, X is a halogen, and n is a number from 1 to 3;
• and
• (C) an organic silicon compound having the general formula RnSi(OR′)4-n where R and R′ each is independently selected from the group consisting of alkyl, cycloalkyl, aryl and haloalkyl and n is an integer from 0 to 3;
• wherein the ratio of component (B) to component (A) is, measured as the molar ratio of aluminum to titanium, from 5 to 1000, and the ratio of component (C) to component (A) is, measured as the molar ratio of silicon to titanium, from 2 to 100.