| 摘要 |
<p>A polymerization catalyst comprises chromium oxide and at least one of manganese, cobalt and nickel oxides on a silica-alumina support, at least part of the chromium being in the hexavalent state. The latter requirement may be ensured by heating the catalyst, e.g. at 350 DEG -1500 DEG F. in a non-reducing anhydrous atmosphere. The catalyst support may contain additionally, e.g. magnesia or zirconia, and the used catalyst may be regenerated by oxidation. Reference has been directed by the Comptroller to Specification 858,945.ALSO:An ethylene copolymer is prepared by contacting a major proportion of ethylene with a minor proportion of a C3-8 aliphatic olefin, at 100 DEG -325 DEG F., in the presence of a catalyst comprising chromium oxide and at least one of manganese, cobalt and nickel oxides on a silica-alumina support, at least part of the chromium being in the hexavalent state. The latter requirement may be ensured by heating the catalyst, e.g. at 350 DEG -1500 DEG F. in a non-reducing anhydrous atmosphere. The polymerization is preferably effected in an inert hydrocarbon diluent; in the example ethylene and butene-1 are copolymerized in cyclohexane. Other comonomers mentioned are propylene, pentene-1, hexene-1, octene-1, 4-methylpentene-1 and 4-methylhexene-1. The catalyst support may contain additionally, e.g. magnesia or zirconia, and the used catalyst may be regenerated by oxidation. Reference has been directed by the Comptroller to Specification 858,945.</p> |
