Catalyst systems that include silyl ether moieties
Catalyst systems for tetramerizing ethylene to form 1-octene may include a catalyst which may include a chromium compound coordinated with a ligand and a co-catalyst which may include an organoaluminum compound. The ligand may have a chemical structure according to Chemical Structure (I), wherein R 5 , R 6 , and R 7 are each independently chosen from a (C 1 -C 50 ) hydrocarbyl group or a (C 1 -C 50 ) heterohydrocarbyl group, and wherein the (C 1 -C 50 ) hydrocarbyl or (C 1 -C 50 ) heterohydrocarbyl groups of R 5 , R 6 , and R 7 have greater than 10 carbon atoms combined and R A , R B , R C , and R D and R 1 , R 2 , R 3 , and R 4 , are independently chosen from a hydrogen atom or a (C 1 -C 50 ) hydrocarbyl group.
1. A catalyst system for tetramerizing ethylene to form 1-octene, the catalyst system comprising:
a catalyst comprising a chromium compound coordinated with a ligand; and
a co-catalyst comprising an organoaluminum compound,
wherein:
the ligand has the chemical structure:
wherein:
R 5 , R 6 , and R 7 are each independently chosen from a (C 1 -C 50 ) hydrocarbyl group or a (C 1 -C 50 ) heterohydrocarbyl group, and wherein the (C 1 -C 50 ) hydrocarbyl or (C 1 -C 50 ) heterohydrocarbyl groups of R 5 , R 6 , and R 7 have greater than 10 carbon atoms combined; and
R A , R B , R C , and R D and R 1 , R 2 , R 3 , and R 4 , are independently chosen from a hydrogen atom or a (C 1 -C 50 ) hydrocarbyl group.
2. The catalyst system of claim 1 , wherein R 5 , R 6 , and R 7 are each independently an unsubstituted (C 1 -C 50 ) linear or branched alkyl group.
3. The catalyst system of claim 1 , wherein R 5 , R 6 , and R 7 are each independently an unsubstituted (C 4 -C 20 ) linear alkyl group.
4. The catalyst system of claim 1 , wherein one or more of R 5 , R 6 , and R 7 are substituted or unsubstituted aryl groups, and wherein R 5 , R 6 , and R 7 have greater than 15 carbon atoms combined.
5. The catalyst system of claim 1 , wherein one or more of R A , R B , R C , and R D are substituted or unsubstituted aryl moieties.
6. The catalyst system of claim 1 , wherein:
R 1 , R 2 , R 3 , and R 4 are each a hydrogen atom; and
R A , R B , R C , and R D are each a phenyl group.
7. The catalyst system of claim 1 , wherein the chromium compound comprises one or more of an organic chromium salt, an inorganic chromium salt, a chromium coordination complex, and a chromium organometallic complex.
8. The catalyst system of claim 1 , wherein the chromium compound comprises one or more of chromium trichloride tris-tetrahydrofuran complex, chromium dichloride bis-tetrahydrofuran complex, (benzene)tricarbonyl chromium, chromium (III) octanoate, chromium (III) acetylacetonate, chromium hexacarbonyl, chromium (III) 2-ethylhexanoate, and chromium (III) 2,2,6,6-tetramethyl-3,5-heptanedionate.
9. The catalyst system of claim 1 , wherein the catalyst comprises the ligand in an amount such that a molar ratio of the ligand to chromium is from 0.1 to 10.0.
10. The catalyst system of claim 1 , wherein the organoaluminum compound has the structure:
wherein R 8 , R 9 , and R 10 are each selected from the group consisting of a hydrogen atom and an unsubstituted (C 1 -C 20 ) linear or branched alkyl group.
11. 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, ethylaluminoxane, and modified methylaluminoxane.
12. The catalyst system of claim 1 , wherein the catalyst system comprises the co-catalyst in an amount such that a molar ratio of the organoaluminum compound to the chromium compound is from 100 to 5000.
13. 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.
14. The method of claim 13 , wherein the 1-octene is formed in conditions of:
a reactor pressure from 2 bar to 100 bar; and
a reactor temperature from 30° C. to 180° C.
15. The method of claim 13 , wherein ethylene is contacted with the catalyst system in the presence of a reaction medium, wherein the reaction medium comprises one or more of cyclohexane, methylcyclohexane, decahydronapthalene, chlorobenzene, toluene, xylene, heptane, and isooctane.