| 摘要 |
A polymerization catalyst comprises gamma alumina and a reduced titanium halide or zirconium halide. Gamma alumina containing up to 40 per cent other materials, such as silica or magnesia and prepared by heating aluminium-containing materials between 500 DEG to 900 DEG C. is impregnated, preferably, with 0.2 to 20 per cent by weight titanium tetrachloride or zirconium tetrachloride. Reduction of the metal halide is effected by contacting the impregnated alumina with a reducing agent, for example: (i) a solution, dispersion or amalgam with mercury of an alkali or an alkaline earth metal; (ii) metal hydrides or complexes of metal hydride, for example sodium hydride or lithium aluminium hydride; (iii) organo-metallic compounds of Groups I, II and III of the Periodic Classification Table according to Mendeleeff, especially n-butyl lithium, diethyl zinc, triethyl aluminium, tri-n-propyl aluminium, tri-isobutyl aluminium, ethyl aluminium dichloride and diethyl aluminium chloride; or (iv) a reducing gas at elevated temperatures, such as hydrogen at 250 DEG to 500 DEG C. The gamma alumina can be impregnated with gaseous titanium tetrachloride with or without an inert gas diluent, such as nitrogen or a solution of the tetrahalide with or without an inert diluent solvent, such as benzene. Reduction is done in the liquid or gaseous phase with the reducing agents. Alternatively, the reducing agent can be deposited on the gamma alumina followed by the metal tetrahalide in the liquid or gaseous phase.ALSO:Olefines, preferably alpha olefins with 2 to 8 carbon atoms, are polymerized, using as catalyst gamma alumina and a reduced titanium or zirconium halide. Specified olefins are ethylene, propylene, isobutylene, butene-1, 1,3-butadiene, and the pentenes, hexenes, heptenes and octenes which have a terminal olefinic bond and mixtures thereof. The polymerization may take place in the presence of an inert reaction medium such as a saturated hydrocarbon and may be continuous, semi-continuous or batch-type.
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