Process for producing polypropylene impact block copolymers

A process for producing a polypropylene impact copolymer by polymerizing propylene and optionally a monomer selected from the group consisting of ethylene, butene-1, pentene-1, and hexene-1 in a first reactor in the presence of a titanium, magnesium, halogen, and a inside electron donor catalyst, an organoaluminum cocatalyst, and an outside electron donor, R12Si(OR2)2, to produce a first polymer which enters a second reactor where it is reacted with propylene and another monomer in the absence of additional catalyst and in the presence of a third electron donor, Si(OR3)4 is provided.