| abstract |
Disclosed is a process for producing a polyolefin which comprises contacting an olefin with a catalyst comprising: n (A) a solid catalyst component comprising, as essential components, (a) a magnesium compound, (b) halogenated titanium and (c) an electron donor compound; n (B) an organoaluminum compound; and n (C) an organosilicon compound selected from a group consisting of an organosilicon compound (C-1) having the general formula: n n (R.sup.1 O)(R.sup.2 O).sub.3-n Si(OR.sup.3).sub.n (I) n n wherein R 1 is a branched hydrocarbon residue; R 2 and R 3 may be the same as or different from each other, and are linear or branched hydrocarbon residues, respectively; and n is from 2 to 3; n an organosilicon compound (C-2) having the general formula: ##STR1## wherein R 4 is a hydrocarbon residue in which a carbon atom adjacent to Si is a tertiary carbon atom; and R 5 is a linear or branched hydrocarbon residue; and n an organosilicon compound (C-3) having the general formula: n n R.sup.6 R.sup.7 Si(OR.sup.8).sub.2 (III) n n wherein R 6 is a branched hydrocarbon residue; R 7 is a cyclic saturated hydrocarbon residue; and R 8 is a linear or branched hydrocarbon residue. |