GB1065514A - A process for the polymerisation of ª‡-olefines - Google Patents

Abstract

a -Olefines of formula CH2=CHR, in which R represents H or an aliphatic radical containing 1 to 5 carbon atoms in the main chain which may be unsubstituted or substituted by an alkyl- or phenyl group, e.g. ethylene, propylene or 4-methyl pentene-1, are polymerized in an organic solvent medium such as diesel oil or n-heptane in the presence of a catalyst comprising (a) a titanium halide, (b) a dialkyl aluminium halide and/or an alkyl aluminium sesquihalide, if desired with addition of a trialkyl aluminium to convert the monoalkyl aluminium halide into a dialkyl aluminium monohalide, and (c) an alkali metal- or alkaline earth metal salt of a carboxylic acid, which may be substituted by a halogen, or in the presence of a conversion product of these salts with one or more of the aforesaid catalyst components. The titanium halide (a) (e.g. TiCl4) is preferably reduced (to TiCl3) with ethyl aluminium sesquichloride prior to the addition of components (b) and (c). The exemplified components (b) are diethyl aluminium chloride, ethyl aluminium sesquichloride and triethyl aluminium. For component (c) sodium and potassium acetates are preferred, the salts exemplified being calcium acetate and the sodium salts of benzoic, butyric, monochloracetic, trichloracetic and oxalic acids. The catalyst has a high activity and produces a polymer of high stereospecificity, e.g. atactic amorphous polymers are produced from propylene and higher olefines. The reaction is terminated with butanol and the polymer washed with acetone.