Hydrocarbyl-modified methylaluminoxane cocatalyst for constrained geometry procatalysts

A process of polymerizing olefin monomers, the process comprising reacting ethylene and optionally one or more olefin monomers in the presence of a catalyst system, wherein the catalyst system comprises:

• hydrocarbyl-modified methylaluminoxane having less than 25 mole percent trihydrocarbyl aluminum compounds AlRA1RB1RC1 based on the total moles of aluminum, where RA1, RB1, and RC1 are independently linear (C1-C40)alkyl, branched (C1-C40)alkyl, or (C6-C40)aryl;
• and
• one or more procatalysts comprising a metal-ligand complex according to formula (I):
• where:
• Ti is titanium;
• n is 1, 2, or 3;
• each X is a monodentate ligand or bidentate ligand independently chosen from unsaturated (C2-C50)hydrocarbon, unsaturated (C2-C50)heterohydrocarbon, saturated (C2-C50)heterohydrocarbon, (C1-C50)hydrocarbyl, (C6-C50)aryl, (C6-C50)heteroaryl, cyclopentadienyl, substituted cyclopentadienyl, (C4-C12)diene, halogen, —N(RN)2, and —NCORC;
• the metal-ligand complex is overall charge-neutral;
• Cp is selected from the group consisting of cyclopentadienyl and RS substituted cyclopentadienyl, the Cp being bound in an is bonding mode to Ti, wherein RS is independently selected from the group consisting of (C1-C20)alkyl, (C1-C20)heteroalkyl, (C1-C20)aryl, or RS substituent (C1-C20)aryl, (C1-C20)heteroaryl, or RS substituent (C1-C20)heteroaryl, wherein two adjacent RS groups are optionally linked to form a ring;
• N is nitrogen;
• Y is carbon or silicon and is covalently bonded to Cp;
• and
• R1 and R2 are independently selected from —H, (C1-C40)hydrocarbyl, and (C1-C40)heterohydrocarbyl;
• R3 are independently selected from (C1-C40)hydrocarbyl, and (C1-C40)heterohydrocarbyl.