| Abstract |
A process for the polymerization and copolymerization of olefinically unsaturated compounds is described, comprising an organometallic compound of aluminium and a second component- obtained by bringing a magnasium compound and/or a titanium,vanadium or chromium compound and possibly at least one compound of a second metal chosen from v, a1, zr, hf, mo and nd, into contact with a porous support consisting of microbeads of aerogels of one or more inorganic oxides distinguished by low densitv. high porosity and the fact that at at least 90% of the pores have a diameter lying within a very narrow range of values. The process for the polymerization or copolymerizlition of olefinically unsaturated compounds based on the use of said catalyst is also described. |