GB934119A - Polymerisation catalysts - Google Patents

Abstract

Polymerization catalysts are made by reacting a compound of a transition metal of Group IV-VI with at least one organic silicon compound containing the grouping <FORM:0934119/III/1> , where R is a phenyl radical which may bear substituent groups, and the remaining valency is satisfied by an aromatic, cycloaliphatic or aliphatic group or hydrogen. The transition metals of Group IV-VI of the Periodic Table are defined as those metals occupying any of the 4th to 6th places after the inert gases in any of the long periods of the Table, the rare-earths occupying only one such place. Specified silicon compounds are phenyl silane and diphenyl silane. The preferred transition metal compounds are halides especially chlorides of aluminium, titanium and vanadium. A particularly effective catalyst component is formed by combining a transition metal halide in a valency state lower than its maximum with a Lewis acid, e.g. TiCl4, VCl4 or AlBr3. Prior to use the catalyst components may be ball-milled. Specifications 830,424 and 877,050 are referred to.ALSO:a -Olefines are polymerized in the presence of catalysts made by reacting a compound of a transition metal of Group IV-VI of the Periodic Table with at least one organic silicon compound containing the grouping <FORM:0934119/IV(a)/1> where R is a phenyl radical which may bear substituent groups, and the remaining valency is satisfied by an aromatic, cycloaliphatic or aliphatic group or hydrogen. The transition metals of Group IV-VI of the Periodic Table are defined as those metals occupying any of the 4th to 6th places after the inert gases in any of the long periods of the Table. Specified silicon compounds are phenyl silane and diphenyl silane. The preferred transition metal compounds are halides, especially chlorides, of aluminium, titanium, and vanadium. The catalysts are especially useful for polymerizing ethylene. By their use higher a -olefines may be polymerized to solids, semi-solids or oils. Polymerization is preferably effected in an inert hydrocarbon solvent or unreacted liquid monomer in which the catalysts form slurries, at elevated temperature, e.g. 50 DEG -100 DEG C. or higher, and under superatmospheric pressure. Since oxygen or water destroys the catalysts polymerization is effected in their absence. Comparative examples are given. Specifications 830,424 and 877,050 are referred to.