| 摘要 |
Titania, and a coprecipitated mixture of titania and alumina, suitable as a catalyst base are made as follows: (1) titania, by dissolving tetra-n-butyl titanate in dry benzene, hydrolysing the titanate with water, recovering the gel product, drying at 120 DEG C., and finally roasting the product of 400 DEG C.; (2) a mixture of titania and alumina by dissolving tetra-n-butyl titanate and aluminium isopropoxide in dry benzene, hydrolysing with water, and recovering the precipitated product as under (1). The products may be halogenated.ALSO:A polymerization catalyst comprises a mixture of (a) a reducing agent and (b) a product obtained by contacting at elevated temperature a halogenated organic compound with (1) an oxide of a metal of Group IVa of the Mendeleeff Periodic Table, or aluminol or (2) a mixture of two or more compounds of class (1), or (3) a compound obtained or obtainable by the reaction of two or more compounds of class (1). The reducing agent may be aluminium, magnesium or zinc, a metal of Group IVa, Va, VIa, VIIa, or VIII, e.g. titanium, or iron, hydrogen, hydrazine, or an unsaturated hydrocarbon. The Group IVa metal may be Ti, Zr, Hf, or Th, and the oxides of these metals is generally coprecipitated with alumina. Specified halogenated compounds are methylene dichloride, chloroform, carbon tetrachloride, methylene difluoride, and carbon tetrafluoride. The catalyst is used to polymerize olefinically unsaturated compounds such as ethylene, propylene, butene-1, 4-methylpentene-1, butadiene, styrene, or isoprene, and acetylenes. The polymerization is preferably effected in a diluent, and the catalyst may be a fixed bed, a moving bed or in suspension. Specification 950,219 is referred to. |
