GB865407A - Polymerisation of ethylene - Google Patents

Abstract

Ethylene is polymerized at an elevated temperature and pressure in the presence of a three component catalyst mixture consisting of aluminium, a metal halide Friedel-Crafts catalyst other than a titanium or vanadium salt and a halide of titanium or vanadium in a liquid vehicle, the molar proportion of aluminium amounting 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 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 absorbed or chemically combined oxygen from the metal or form new metallic surfaces by mechanical or chemical action. The Friedel-Crafts catalyst may be aluminium chloride, stannic chloride, beryllium fluoride or mercuric chloride. The preferred halides are titanium tri- or tetrachloride. The trihalide may be in the form of a black, brown or purple powder. The liquid vehicle may be n-pentane, hexane, decane, cyclohexane, or petroleum ether. The temperature is preferably between 70 DEG and 200 DEG C. and the pressure between 150 and 1,000 lbs./sq. inch.ALSO:A polymerization catalyst consists of (1) aluminium, (2) a metal halide Friedel-Crafts catalyst other than a titanium or vanadium salt, and (3) a halide of titanium or vanadium in a liquid vehicle, the molar proportion of aluminium amounting 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 another metal, e.g. as an alloy. The Friedel-Crafts catalyst may be aluminium chloride, stannic chloride, beryllium fluoride, or mercuric chloride. The preferred halides are titanium tri- or tetrachloride. The trihalide may be in the form of a black, brown, or purple powder. The liquid vehicle may be n-pentane, hexane, decane, cyclohexane, or petroleum ether. 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.