Ziegler-Natta catalysts for the production of polyethylene

A process for polymerizing ethylene-based polymers, the process comprising:

• contacting ethylene and optionally one or more α-olefins in the presence of a catalyst system, wherein the catalyst system comprises a heterogeneous procatalyst, the heterogeneous procatalyst comprising:
• a titanium species,
• a hydrocarbon-soluble transition metal compound having a structure M(OR1)z, where:
• M is a transition metal in an oxidation state of +2 or +3;
• and
• each R1 is independently (C1-C30)hydrocarbyl or —C(O)R11, wherein R11 is (C1-C30)hydrocarbyl;
• and
• z is 2 or 3;
• wherein each R1 and R11 may be optionally substituted with one or more than one halogen atoms, or one or more than one —Si(RS)3, where each RS is (C1-C30)hydrocarbyl;
• a chlorinating agent having a structure A(Cl)x(R2)3-x, where:
• A is aluminum or boron;
• R2 is (C1-C30)hydrocarbyl;
• and
• x is 1 or 2;
• and
• a magnesium chloride component.

A process of making a procatalyst, the process comprising:

• preparing a MgCl2 slurry in a hydrocarbon solvent;
• and
• mixing a chlorinating agent, a hydrocarbon-soluble transition metal compound, and a titanium species into the MgCl2 slurry,
• wherein
• the transition metal compound has a structure M(OR1)z, where:
• M is a non-reducing transition metal in an oxidation state of +2 or +3;
• each R1 is independently (C1-C30)hydrocarbyl or —C(O)R11, wherein R11 is (C1-C30)hydrocarbyl;
• and
• z is 2 or 3;
• wherein each R1 and R11 may be optionally substituted with one or more than one halogen atoms, or one or more than one —Si(RS)3, where each RS is (C1-C30)hydrocarbyl;
• and
• the chlorinating agent has a structure A(Cl)x(R2)3-x, where:
• A is aluminum or boron;
• R2 is (C1-C30)hydrocarbyl;
• and
• x is 1, 2, or 3.