| 摘要 |
Catalysts for use in the polymerization of olefins (see Group IV (a)) are obtained by admixing a halogen containing compound of a Group IVa, Va or VIa metal, with a compound R3Me-O-MeR3, wherein Me is a Group IVb metal and R is a hydrocarbon radical. Catalyst components disclosed are hexaethyl, -butyl, -hexyl and -cyclo-hexyl distannoxanes; titanium and vanadium tetrachlorides, zirconium and hafnium tetrabromides, titanium trichloride, vanadium pentafluoride, and oxyhalides such as vanadium oxytrichloride. Optionally trialkyl tin hydroxides and tetraalkyl and tetracycloalkyl tin compounds may be included. Catalyst formation may be in situ in the reaction vessel and in an inert solvent such as hexane, cyclohexane, dimethyl cyclohexane, octane, gasoline, benzene, xylene, toluene, carbon tetrachloride or mixtures thereof.ALSO:Olefins are polymerized with the aid of a mixture of a halogen containing compound of a metal of Group IVa, Va or VIa, with a compound R3Me-O-MeR3, wherein Me is a Group IVb metal and R is a hydrocarbon radical. Olefins specified are those having up to 8 carbon atoms and particularly ethylene, propylene, butylene, isobutylene, butadiene, isoprene and mixtures thereof. Catalyst components disclosed are hexa-ethyl, -butyl, -hexyl and -cyclohexyl distannoxanes; titanium and vanadium tetrachlorides, zirconium and hafnium tetrabromides, titanium trichloride, vanadium pentafluoride, and oxyhalides such as vanadium oxytrichloride. Optionally trialkyl tin hydroxides and tetraalkyl and tetracycloalkyl tin compounds may be included in the catalyst composition. Catalyst formation may be in situ in the vessel and in an inert solvent suitable for use in the polymerization, e.g. hexane, cyclohexane, dimethyl cyclohexane, octane, gasoline, benzene, xylene, toluene, carbon tetrachloride and mixtures thereof. The yield and molecular weight of the polyolefins may be altered by varying the temperature, the pressure, or the molar proportions of the catalyst components. The products may be obtained in granular form and may be purified with organic solvents or dilute aqueous or organic solutions of acids, e.g. aqueous or methanolic hydrochloric acid. The high molecular weights of the polyolefins may be reduced by boiling with 30 to 40 per cent nitric acid. Examples illustrate the continuous addition of ethylene during the polymerization. The products find application in moulding and in the production of foils, films, fibres and threads.
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