Ziegler-natta bimetallic catalysts, catalytic systems including the same and processes for polymerizing linear alpha-olefins

Abstract

This invention relates to a Ziegler-Natta bimetallic catalyst supported on MgCl2, comprising: titanium (Ti(III)) with an oxidation state of +3, and optionally titanium (Ti(IV)) with an oxidation state of +4; and at least one metal selected from hafnium (Hf(IV)) with an oxidation state of +4 and zirconium (Zr(IV)) with an oxidation state of +4; wherein: the Mg / Ti molar ratio is not higher than 3.0, preferably 0.5 to 2.7, more preferably 1.0 to 2.5; and the (Hf and / or Zr) / Ti molar ratio is 0.5 to 5.0, preferably 1.0 to 4.0, more preferably 1.5 to 3.5. The above-described Ziegler-Natta bimetallic catalyst supported on MgCl2 can be combined with at least one organoaluminum co-catalyst in a catalyst system. This catalyst system can be used in processes for polymerizing at least one linear α-olefin. The present invention relates to Ziegler-Natta bimetallic catalysts supported on MgCl2, which contains: titanium in the oxidation state +3 (Ti(III)), and optionally titanium in the oxidation state +4 (Ti(IV)); and at least one metal selected from hafnium in the oxidation state +4 (Hf(IV)) and zirconium in the oxidation state +4 (Zr(IV)); wherein: the Mg / Ti molar ratio is not higher than 3.0, preferably from 0.5 to 2.7, more preferably from 1,0 to 2.5; and the (Hf and / or Zr) / Ti molar ratio is from 0.5 to 5.0, preferably from 1.0 to 4.0, more preferably from 1.5 to 3.5. The above Ziegler-Natta bimetallic catalysts supported on MgCl2 may be included into a catalytic system in combination with at least one organoaluminum co-catalyst. Said catalytic system may be used in a process for polymerizing at least one linear α-olefin.

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