Process for the polymerization of olefins

Claim 1

A process for the low pressure polymerization and copolymerization of alpha-olefins which comprises conducting the polymerization and copolymerization in the presence of a catalyst system comprising: (a) an organic compound of a metal of Groups IA, IIA, IIB, IIIA and IVA of the Periodic Table, being selected from alkyl metal compounds, alkyl metal hydrides and alkyl metal halides; and (b) a solid catalyst complex, said complex prepared by reacting (1) a transition metal compound of the metals of Groups IVB, VB and VIB of the Periodic Table selected from halides, oxyhalides, alkoxyhalides, oxyalkoxides, and alkoxides with (2) a porous aluminum oxide having an internal porosity of greater than 0.3 cm 3 /g and a specific surface area of between 200 and 400 m 2 /g on which is chemically attached an amount of magnesium compound selected from organic oxygen containing magnesium compounds containing only C 1 -C 20 organic radical bonded to magnesium via oxygen and magnesium dihalides, said amount being such that between 1×10 -3 and 5×10 -3 milligram-atom of magnesium is present per square meter of specific surface area of the porous oxide and the magnesium compound having been chemically attached on the porous aluminum oxide in a liquid medium, said medium being in the form of water or of an organic diluent.