| 摘要 |
Ethylene is polymerized at an elevated temperature and pressure in the presence of a threecomponent catalyst mixture consisting of aluminium, a titanium tetrahalide or a vanadium tetrahalide, and a di- or tri-halide of titanium or vanadium in a liquid vehicle, the molar proportion of aluminium amounting to at least onethird of the molar total of the other two components forming the catalyst mixture. The aluminium is preferably finely divided and may be mixed with another metal, e.g. as an alloy. The aluminium may be in an "active" form, i.e. it may have been treated, in the absence of oxygen, to remove adsorbed or chemically combined oxygen from the metal or to form new metallic surfaces by mechanical or chemical action, e.g. grinding, milling, shaving, or chipping. Mixtures of titanium and vanadium tetrahalides may be employed. Titanium trichloride may be used in the form of a black, brown, or violet powder. The liquid vehicle may be n-pentane, hexane, decane, or cyclohexane. The temperature may be between 70 and 200 DEG C. and the pressure between 150 and 1,000 lbs. per square inch. The ethylene may contain minor amounts of propylene or n-butene.ALSO:A polymerization catalyst consists of aluminium, a titanium tetrahalide or vanadium tetrahalide, and a di- or tri-halide of titanium or vanadium in a liquid vehicle, the molar proportion of aluminium amounts to at least one third of the molar total of the other two components forming the catalyst mixture. The aluminium is preferably finely divided and may be mixed with other metals, e.g. as an alloy. Mixtures of titanium and vanadium tetrachlorides may be employed. Titanium trichloride when used may be in the form of a black, brown, or purple powder. The liquid may be n-pentane, hexane, decane, or cyclohexane. The aluminium may be in an "active" form, i.e. it may have been treated to remove adsorbed or chemically combined oxygen, or form fresh surfaces by mechanical or chemical treatment. |
