Hydrocarbyl-modified methylaluminoxane cocatalyst for constrained geometry procatalysts

1 . 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 AlR A1 R B1 R C1 based on total moles of aluminum in the hydrocarbyl-modified methylaluminoxane, where R A1 , R B1 , and R C1 are independently linear (C 1 -C 40 )alkyl or branched (C 1 -C 40 )alkyl; 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 (C 2 -C 50 )hydrocarbon, unsaturated (C 2 -C 50 )heterohydrocarbon, saturated (C 2 -C 50 )heterohydrocarbon, (C 1 -C 50 )hydrocarbyl, (C 6 -C 50 )aryl, (C 6 -C 50 )heteroaryl, cyclopentadienyl, substituted cyclopentadienyl, (C 4 -C 12 )diene, halogen, and —NCOR C ;

each R c is independently substituted (C 1 -C 30 )hydrocarbyl, unsubstituted (C 1 -C 30 )hydrocarbyl, substituted (C 1 -C 30 )heterohydrocarbyl, or unsubstituted (C 1 -C 30 )heterohydrocarbyl;

the metal-ligand complex is overall charge-neutral;

Cp is selected from the group consisting of cyclopentadienyl and R S substituted cyclopentadienyl, the Cp being bound in an η 5 bonding mode to Ti, wherein R S is independently selected from the group consisting of (C 1 -C 20 )alkyl, (C 1 -C 20 )heteroalkyl, (C 1 -C 20 )aryl, or R S substituent (C 1 -C 20 )aryl, (C 1 -C 20 )heteroaryl, or R S substituent (C 1 -C 20 )heteroaryl, wherein two adjacent R S groups are optionally linked to form a ring;

N is nitrogen;

Y is carbon or silicon and is covalently bonded to Cp; and

R 1 and R 2 are independently selected from —H, (C 1 -C 40 )hydrocarbyl, and (C 1 -C 40 )heterohydrocarbyl;

R 3 is selected from (C 1 -C 40 )hydrocarbyl or (C 1 -C 40 )heterohydrocarbyl;

R A1 , R B1 , and R C1 are methyl, ethyl, propyl, 2-propyl, butyl, n-octyl, nonyl, decyl, undecyl, or dodecyl; and

at least one of R A1 , R B1 , and R C1 is different from the other R A1 , R B1 , and R C1 .

2 . The process of polymerizing olefin monomers according to claim 1 , where the hydrocarbyl-modified methylaluminoxane has less than 20 mole percent of trihydrocarbyl aluminum compounds based on the total moles of aluminum in the hydrocarbyl-modified methylaluminoxane.

3 . The process of polymerizing olefin monomers according to claim 1 , where the hydrocarbyl-modified methylaluminoxane has less than 15 mole percent of trihydrocarbyl aluminum compounds based on the total moles of aluminum in the hydrocarbyl-modified methylaluminoxane.

4 . The process of polymerizing olefin monomers according to claim 1 , where the hydrocarbyl-modified methylaluminoxane has less than 10 mole percent of trihydrocarbyl aluminum compounds based on the total moles of aluminum in the hydrocarbyl-modified methylaluminoxane.

5 . The process of polymerizing olefin monomers according to claim 1 , wherein the catalyst system does not contain a borate activator.

6 . The process of polymerizing olefin monomers according to claim 1 , wherein the one or more olefin monomers is (C 3 -C 20 )α-olefin.

7 . The process of polymerizing olefin monomers according to claim 1 , wherein the one or more olefin monomers is not (C 3 -C 20 )α-olefin.

8 . The process of polymerizing olefin monomers according to claim 1 , wherein the one or more olefin monomers is cyclic olefin.

9 . The process of polymerizing olefin monomers according to claim 1 , wherein R 1 and R 2 are independently (C 1 -C 12 )alkyl or (C 6 -C 20 )aryl.

10 . The process of polymerizing olefin monomers according to claim 1 , wherein R 1 and R 2 are methyl, ethyl, propyl, or phenyl.

11 . The process of polymerizing olefin monomers according to claim 1 , wherein R 3 is (C 1 -C 12 )alkyl.

12 . The process of polymerizing olefin monomers according to claim 1 , wherein R 3 is tert-butyl, tert-octyl, or n-octyl.

13 . The process of polymerizing olefin monomers according to claim 1 , wherein Cp is tetramethylcyclopentadienyl.

14 . The process of polymerizing olefin monomers according to claim 1 , wherein Cp is selected from:

15 . The process of polymerizing olefin monomers according to claim 1 , wherein the process is a solution polymerization reaction.

16 . The process of polymerizing olefin monomers according to claim 1 , wherein R A1 , R B1 , and R C1 comprise methyl and at least another one of ethyl, propyl, 2-propyl, butyl, n-octyl, nonyl, decyl, undecyl, or dodecyl.

17 . The process of polymerizing olefin monomers according to claim 1 , the hydrocarbyl-modified methylaluminoxane has at greater than or equal to 2.5 mole percent trihydrocarbyl aluminum compounds AlR A1 R B1 R C1 based on total moles of aluminum in the hydrocarbyl-modified methylaluminoxane.

18 . 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 AlR A1 R B1 R C1 based on total moles of aluminum in the hydrocarbyl-modified methylaluminoxane, where R A1 , R B1 , and R C1 are independently linear (C 1 -C 40 )alkyl, branched (C 1 -C 40 )alkyl, or (C 6 -C 40 )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 substituted cyclopentadienyl;

the metal-ligand complex is overall charge-neutral;

Cp is selected from the group consisting of cyclopentadienyl and R S substituted cyclopentadienyl, the Cp being bound in an η 5 bonding mode to Ti, wherein R S is independently selected from the group consisting of (C 1 -C 20 )alkyl, (C 1 -C 20 )heteroalkyl, (C 1 -C 20 )aryl, or R S substituent (C 1 -C 20 )aryl, (C 1 -C 20 )heteroaryl, or R S substituent (C 1 -C 20 )heteroaryl, wherein two adjacent R S groups are optionally linked to form a ring;

N is nitrogen;

Y is carbon or silicon and is covalently bonded to Cp; and

R 1 and R 2 are independently selected from —H, (C 1 -C 40 )hydrocarbyl, and (C 1 -C 40 )heterohydrocarbyl;

R 3 are independently selected from (C 1 -C 40 )hydrocarbyl, and (C 1 -C 40 )heterohydrocarbyl.

19 . The process of polymerizing olefin monomers according to claim 16 , wherein Cp is selected from: