| 摘要 |
The invention relates to a process for preparing a catalytic system for producing ethylene-propylene copolymers. The process for preparing a catalytic system consists, in a first stage, in impregnating an inert carrier made of a vanadium compound having an oxidation state ranging from 3 to 5, with a hydrocarbon or halohydrocarbon solution, in a second stage, possibly removing from the impregnated support the solvent used in the first stage, and in the third stage, treating the vanadium-impregnated carrier resulting in the first or second stage, with a hydrocarbon solution of a compound having the general formula (I) RnAIXm, where R is an alkyl radical C1-C20, X is a halogen, n+m =3 and m is a integer number whose value ranges from 0 to 2, the third stage being carried out in an ethylene or alpha-olefin atmosphere, the molar ratio between the aluminium of the third stage and vanadium of the first stage being of 1:1 to 6:1, and finally separating and possibly purifying the catalyst with vanadium content resulting in the third stage.
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