Patent ID: 8598285

Claim:
A process for the preparation of 1-butene homopolymers or 1-butene/alpha olefin copolymers comprising the step: contacting (i) 1-butene or (ii) 1-butene and at least one alpha olefin wherein the alpha olefin is present in 0.1 to 20 mol % and wherein the alpha olefin is selected from ethylene, propylene or alpha olefins of formula CH 2 ═CHZ wherein Z is a C 3 -C 20 alkyl radical with a catalyst system under polymerization conditions wherein the catalyst system comprises: (a) a solid component comprising a Ti compound and an internal electron-donor compound supported on MgCl 2 ; (b) an alkylaluminum cocatalyst; and (c) a compound of formula (I) as external donor wherein: R 1 , R 2 , R 3 R 4 and R 5 equal to or different from each other, are hydrogen atoms or C 1 -C 20 hydrocarbon radicals; or two R 1 , R 2 , R 3 and R 4 can be joined to form a C 5 -C 20 , saturated or unsaturated ring.