Catalysts for polymerization of olefins

Abstract

A catalyst for use in polymerization of olefins which comprises a carrier mainly composed of a magnesium compound precipitated from a solution and a catalytic component supported on the carrier and selected from titanium halides, vanadyl halides and vanadium halides is described. The catalyst is obtained by a process which comprises: (A) mixing (a) at least one magnesium compound with (c) a saturated or unsaturated monohydric or polyhydric alcohol for reaction in dissolved state in the presence of (b) carbon dioxide in an inert hydrocarbon solvent to obtain component (A); (B) subjecting the component (A) to mixing and reaction with (d) a titanium and/or a vanadyl halide and/or a vanadium halide of the general formula, VX.sub.r (OR.sup.8).sub.4-r, and also with (e) at least one boron compound, Si compound and/or Siloxane compound thereby obtaining solid product (I); (C) reacting the solid product (I) with (f) a cyclic ether with or without R.sup.12 OH thereby causing dissolution and re-precipitation to obtain solid product (II); and (D) subjecting the solid product (II) to further reaction with (g) component (B) consisting of a titanium halide and/or a vanadyl halide and/or a vanadium halide, and/or a SiX.sub. s (OR.sup.9).sub.4-s, thereby obtaining solid product (III), followed either by further reaction with a mixture of the component (B) and (h) an electron donor or by reaction of (g) with the solid product (III) obtained by the reaction between the solid product (II) and (h) or (h) with (j) electron donor, thereby obtaining solid product (IV) for use as the catalytic component.