The polymerisation of hydrocarbons

A catalyst composition for polymeriizng olefines contains (a) a titanium chloride, bromide, or iodide having a halogen to titanium atomic ratio in the range of 1.5:1 to 1.95:1 which has been subjected to attrition by grinding, and (b) aluminium chloride, bromide, or iodide in an amount in the range 0.41 to 3.33 gms. of aluminium chloride, bromide, or iodide per litre of hydrocarbon liquid. The component (a) may be prepared by grinding titanium metal with a solution or dispersion of an aluminium halide in a hydrocarbon liquid or by grinding the product obtained by pyrolysing titanium trichloride or dichloride. The grinding may be effected in a ball-mill. In Example 1 the catalyst is made by ball-milling powdered titanium and aluminium bromide in the presence of petroleum ether; in Example 2, the catalyst is made by heating TiCl3 to 700 DEG C. in a stream of argon and ball-milling the product with aluminium bromide in petroleum ether, whilst in Example 6 the effect of pyrolysing TiCl3 under varying conditions prior to ball-milling in the presence of aluminium bromide is described. The (a) component is preferably made from TiCl3, TiCl2, TiBr2 or TiI2 by pyrolysis and in Examples 2 to 4, the product is stated to have an empirical formula TiCl1.82, and in Example 3 a formula TiCl1.65. Tables II and III also give further values for the ratio Cl:Ti. Specification 811, 633 is referred to.ALSO:Olefines are polymerized in the presence of a hydrocarbon liquid and a catalyst composition containing (a) a titanium chloride, bromide, or iodide having a halogen to titanium atomic ratio in the range 1.5: 1 to 1.95: 1 which has been subjected to attrition by grinding, and (b) aluminium chloride, bromide, or iodide in an amount in the range 0.41 to 3.33 gms. of aluminium chloride, bromide, or iodide per litre of the hydrocarbon liquid. The component (a) may be prepared by grinding titanium metal with a solution or dispersion of an aluminium halide in a hydrocarbon liquid or by grinding the product obtained by pyrolysing titanium trichloride or titanium dichloride. The grinding may be effected in a ball mill. Olefines mentioned are ethylene and propylene. In Example 1, ethylene is polymerized in the presence of a catalyst made by ball milling titanium and aluminium bromide in the presence of petroleum ether; in Example 2, ethylene is polymerized in the presence of TiCl3, heated to 700 DEG C. in a stream of argon, and ball-milled with aluminium bromide in petroleum ether, and