Polymerisation of ethylene

A catalyst for polymerizing ethylene is formed by mixing a titanium halide with an organometallic compound obtained by replacing a hydrogen atom of a non-cyclic aliphatic or an aromatic hydrocarbon with lithium or sodium; specified compounds being sodium and lithium butyls, phenyls and benzyls, while the halide may be TiCl4, TiCl3 or TiCl2. Optionally the organometallic compound may be formed in situ and in a diluent by reaction of sodium or lithium and an alkyl or aryl halide, e.g. chlorobenzene. Specification 827,464 is referred to.ALSO:Ethylene is polymerized by contacting with a catalyst formed by mixing a titanium halide with an organometallic compound obtained by replacing a hydrogen atom of a non-cyclic aliphatic or an aromatic hydrocarbon with lithium or sodium; specified compounds being sodium and lithium butyls, phenyls and benzyls. The halide may be TiCl4, TiCl2 or TiCl3, e.g. as prepared in Specification 827,464. If desired, the catalyst may be formed in the presence of ethylene and optionally the organometallic component may be formed in situ in a diluent by reaction of sodium or lithium and an alkyl or aryl halide (e.g. chlorobenzene). Hydrocarbon and halogenated hydrocarbon diluents are preferably present and the polymerization may be either batchwise or continuous. The addition of ethylene or diluent during the reaction is described. In Example 5 the ethylene is purified before use. Methanol, ethanol, water, conc. HCl and methanolic hydrochloric acid are used in the purification treatments described. The polymers are linear and may be formed into films and fibres.