GB794785A - Improvements in the production of polyolefines - Google Patents

Abstract

Catalysts for the polymerization of olefines (see Group IV (a)) comprise a mixture of a vanadium halide or oxyhalide, aluminium and an aluminium halide, e.g. the chloride or bromide, preferably in the molar ratio of 0.5 to 4 : 1 : 5 to 15. The vanadium compound may be the di-, tri- or tetra-chloride, the oxychloride, or a corresponding bromide. An organic liquid such as an alkyl halide and/or a hydrocarbon is preferably present. The catalysts may eventually be destroyed by treatment with materials such as steam, alcohols, organic solvents, aqueous methanol, or aqueous or alcoholic acids such as methanolic hydrochloric acid. In examples air is excluded and the catalyst components may be ground together.ALSO:Olefines are polymerized using as catalyst a mixture of a vanadium halide or oxyhalide, aluminium and an aluminium halide, e.g. the chloride or bromide. The preferred molar ratios of the components are given. Olefines specified are ethylene, propylene, butenes and mixtures thereof, while the vanadium compound may be the di-, tri- or tetra-chloride, the oxychloride, or a corresponding bromide. The polymerization is preferably carried out in an organic liquid, e.g. an alkyl halide such as ethyl chloride, or an aliphatic, cycloaliphatic or aromatic hydrocarbon, such as pentane, octane or gasoline fractions, or a mixture thereof. The catalysts may be destroyed and the polymers purified by distillation and by treatment with steam, alcohols, organic solvents, aqueous methanol, or aqueous or alcoholic acids such as methanolic hydrochloric acid. The temperature used may be below room temperature. In examples pure ethylene may be used, air may be excluded and the catalyst may be ground. The products range from oils to high molecular weight solids which may be moulded or formed into films.