| abstract |
A Ziegler catalytic system comprising an organometallic compound of a metal of Groups I to III of the Periodic Table and a compound of a heavy metal of Groups IV to VI supported on a carrier, the latter being an activated amorphous alumina or alumino-silicate containing from 0.3 to 30% by weight of salts of metals of Groups IIb, IIIa, VIb and VIII with oxygenated inorganic anions, or of a mixture of the latter with salts of said metals of Groups IIb, IIIa, VIb and VIII with non-oxygenated inorganic anions, said salts being introduced into the carrier by contacting the latter with one or more solutions of said salts and the carrier being then activated by calcination at 250°-700° C. |