Catalyst systems

1. A catalyst system suitable for tetramerizing ethylene to form 1-octene, the catalyst system comprising:

a catalyst having the structure:

[(L∩L)CrX 2 (L 1 ) n ] + [BY 4 ] − or [(L∩L)CrX 2 (L 1 ) n ] + [SO 2 Y] −

wherein:

X is a halogen, a (C 2 -C 30 ) carboxylate, acetylacetonate, or a (C 1 -C 30 ) hydrocarbyl;

L 1 is a neutral coordinating ligand;

n is an integer from 0 to 6;

Y is a (C 6 -C 20 )fluorine-substituted aryl, a (C 6 -C 20 )fluorine-substituted aryloxy, or a (C 1 -C 20 )fluorine-substituted alkoxy; and

L∩L is a bidentate chelating ligand having the structure:

(R 1 )(R 2 )P—Z—P(R 1 )(R 2 )

wherein:

each R 1 and R 2 is independently chosen from a (C 1 -C 50 ) alkyl group or a (C 6 -C 50 ) aryl group; and

Z is a (C 2 -C 50 ) alkylene group, a (C 6 -C 50 ) arylene group, —N(R 7 )—,

—P(R 7 )—, —B(R 7 )—, or —Si(R 7 ) 2 — that links the two P atoms, where R 7 is a (C 1 -C 50 ) alkyl group or a (C 6 -C 50 ) aryl group; and

At least one aluminum containing agent comprising a reaction product of an organoaluminum compound and an antifouling compound, wherein the antifouling compound comprises one or more polyether alcohols or one or more non-polymeric ethers.

2. The catalyst system of claim 1 , wherein the catalyst has the structure:

[(L∩L)CrX 2 (L 1 ) n ] + [BY 4 ] − .

3. The catalyst system of claim 1 , wherein the catalyst has the structure:

[(L∩L)CrX 2 (L 1 ) n ] + [SO 2 Y] − .

4. The catalyst system of claim 1 , wherein the antifouling compound comprises one or more polyether alcohols.

5. The catalyst system of claim 1 , wherein the antifouling compound comprises one or more non-polymeric ethers.

6. The catalyst system of claim 1 , wherein each L 1 is a (C 2 -C 30 ) nitrile, a (C 2 -C 30 ) cyclic ether, a (C 2 -C 30 ) acyclic ether, or an H 2 O ligand.

7. The catalyst system of claim 1 , wherein the organoaluminum compound has the structure:

wherein R 3 , R 4 , and R 5 are each selected from a hydrogen atom, a (C 1 -C 20 ) hydrocarbyl group, and a (C 1 -C 50 ) heterohydrocarbyl group.

8. The catalyst system of claim 1 , wherein the organoaluminum compound comprises one or more of trimethylaluminium, triethylaluminum, tripropylaluminum, tri-iso-butylaluminum, diisobutylaluminium hydride, trihexylaluminum, tri-n-octylaluminium, methylaluminium dichloride, ethylaluminium dichloride, dimethylaluminium chloride, diethylaluminium chloride, aluminium isopropoxide, ethylaluminiumsesquichloride, methylaluminiumsesquichloride, methylaluminoxane (MAO), ethylaluminoxane (EAO), and modified methylaluminoxane (MMAO).

9. The catalyst system of claim 1 , wherein the molar ratio of the antifouling compound to the organoaluminum compound is from 0.001 to 1.

10. A method for tetramerizing ethylene to form 1-octene, the method comprising contacting ethylene with the catalyst system of claim 1 to form a product comprising 1-octene.

11. The method of claim 10 , wherein the ethylene is formed in conditions of:

a reactor pressure from 5 bar to 120 bar; and

a reactor temperature from 25° C. to 180° C.

12. A method of making a catalyst system suitable for tetramerizing ethylene to form 1-octene, the method comprising mixing a chromium compound, an anion-containing compound, a bidentate chelating ligand, and an aluminum containing agent to form the catalyst system, wherein the aluminum containing agent is a reaction product of an organoaluminum compound and an antifouling compound, and wherein the antifouling compound comprises one or more polyether alcohols or one or more non-polymeric ethers.

13. The method of claim 12 , wherein the chromium compound has the structure:

CrX 3 (L 1 ) n

wherein:

X is a halogen, a (C 2 -C 30 ) carboxylate, acetylacetonate, or a (C 1 -C 30 ) hydrocarbyl;

L 1 is a ligand; and

n is an integer from 0 to 6.

14. The method of claim 12 , wherein the anion containing compound has a structure:

M + [BY 4 ] −

wherein:

Y is a (C 6 -C 20 )fluorine-substituted aryl, a (C 6 -C 20 )fluorine-substituted aryloxy, or a (C 1 -C 20 )fluorine-substituted alkoxy; and

M + is a metal inorganic cation or an organic cation.

15. The method of claim 12 , wherein the anion containing compound has a structure:

M + [SO 2 Y] −

wherein:

Y is a (C 6 -C 20 )fluorine-substituted aryl, a (C 6 -C 20 )fluorine-substituted aryloxy, or a (C 1 -C 20 )fluorine-substituted alkoxy; and

M + is a metal inorganic cation or an organic cation.

16. The method of claim 12 , wherein the bidentate chelating ligand has the structure:

(R 1 )(R 2 )P—Z—P(R 1 )(R 2 )

wherein:

each R 1 and R 2 is independently chosen from a (C 1 -C 50 ) alkyl group or a (C 6 -C 50 ) aryl group; and

Z is a (C 2 -C 50 ) alkylene group, a (C 6 -C 50 ) arylene group, —N(R 7 )—, —P(R 7 )—, —B(R 7 )—, or —Si(R 7 ) 2 — that links the two P atoms, where R 7 is a (C 1 -C 50 ) alkyl group or a (C 6 -C 50 ) aryl group.