Treatment of polymers

Catalyst residues containing at least one compound of a transition metal of Groups 4, 5 or 6 are removed from an olefin polymer by adding thereto, in the presence of a hydrocarbon liquid, a reagent A and extracting the mixture with an aqueous solution of reagent B. Reagent A is soluble in hydrocarbons, at least sparingly soluble in water, and forms in the hydrocarbon solution a transition metal coordination compound decomposable by the aqueous solution B, while reagent B is soluble in water and in aqueous solution decomposes the above co-ordination compound to form a stable water-soluble compound insoluble in hydrocarbon liquids. Specified polymers are polyethylene and polypropylene, especially isotactic polypropylene. Specified reagents A are acetyl acetone, propionyl acetone, butyryl acetone, valeryl acetone, hept-3-5-diene, 3-methylpent-2:4-diene, and n-nonyl amine, while specified reagents B are tartaric acid, citric acid, oxalic acid, hydrochloric acid, boric acid, ethylene diamine, polyphosphates, alkali metal phosphate glasses, ethylene diamine tetra-acetic acid and its alkali metal and ammonium salts and mixtures thereof. Specification 877,050 is referred to.