Catalyst systems
Catalyst systems suitable for tetramerizing ethylene to form 1-octene may include a catalyst including a chromium compound coordinated with a ligand and a co-catalyst including an organoaluminum compound. The ligand may have a chemical structure: (R 1 )(R 2 )A-X—C(R 3 )(R 4 ). A and C may be phosphorus. X may be B(R 5 ), Si(R 5 ) 2 , N(R 5 ), wherein R 5 is an aryl group substituted with a halogen, halogenated alkyl or a silyl group, and wherein B, or N, or Si is bound to A and C. R 1 , R 2 , R 3 , and R 4 may be independently chosen hydrocarbyl groups or heterohydrocarbyl groups.
1. A catalyst system suitable 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 a chemical structure: (R 1 )(R 2 )A-X-C(R 3 )(R 4 );
A and C are phosphorus;
X is B(R 5 ), Si(R 5 ) 2 , or N(R 5 ), wherein R 5 is an aryl group substituted with a halogenated alkyl or a silyl group, and wherein the B, the N, or the Si is bound to A and C; and
R 1 , R 2 , R 3 , and R 4 are independently chosen hydrocarbyl groups or heterohydrocarbyl groups.
2. The catalyst system of claim 1 , wherein one or more of R 1 , R 2 , R 3 , and R 4 are substituted or unsubstituted aryl moieties.
3. The catalyst system of claim 1 , wherein the ligand has a chemical structure:
wherein:
each Ar is independently chosen from a substituted or unsubstituted aryl group;
R 6 , R 7 , R 8 , R 9 , and R 10 are each independently chosen from hydrogen or a substituted or unsubstituted hydrocarbyl group; and
one or more of R 6 , R 7 , R 8 , R 9 , and R 10 are groups represented formulaically as C n F 2n+1 or as SiZ 3 , where each Z is independently chosen from a substituted or unsubstituted hydrocarbyl group or a substituted or unsubstituted heterohydrocarbyl group.
4. The catalyst system of claim 3 , wherein one or more of R 7 and R 9 are groups represented formulaically as C n F 2n+1 or as SiZ 3 , where each Z is independently chosen from a substituted or unsubstituted hydrocarbyl group.
5. 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.
6. 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, and a chromium organometallic complex.
7. The catalyst system of claim 1 , wherein the chromium compound comprises one or more of chromium trichloride tris-tetrahydrofuran complex, (benzene)tricarbonyl chromium, chromium (III) octanoate, chromium (III) acetylacetonoate, chromium hexacarbonyl, and chromium (III) 2-ethylhexanoate.
8. The catalyst system of claim 1 , wherein the organoaluminum compound has a structure:
wherein R 11 , R 12 , and R 13 are each selected from a hydrogen atom and a (C 1 -C 20 ) hydrocarbyl group or a (C 1 -C 20 ) heterohydrocarbyl group.
9. 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.
10. The catalyst system of claim 1 , wherein the catalyst system comprises the co-catalyst in an amount such that a molar ratio of aluminum to chromium is from 1 to 5000.
11. 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.
12. The method of claim 11 , 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.
13. A catalyst system suitable 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 a chemical structure:
wherein:
each Ar is independently chosen from a substituted or unsubstituted aryl group;
R 6 , R 7 , R 8 , R 9 , and R 10 are each independently chosen from hydrogen or a substituted or unsubstituted hydrocarbyl group; and
one or more of R 6 , R 7 , R 8 , R 9 , and R 10 are groups represented formulaically as C n F 2n+1 or as SiZ 3 , where each Z is independently chosen from a substituted or unsubstituted hydrocarbyl group or a substituted or unsubstituted heterohydrocarbyl group.
14. The catalyst system of claim 13 , wherein one or more of R 7 and R 9 are groups represented formulaically as C n F 2n+1 or as SiZ 3 , where each Z is independently chosen from a substituted or unsubstituted hydrocarbyl group.
15. The catalyst system of claim 13 , 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.
16. The catalyst system of claim 13 , wherein the chromium compound comprises one or more of an organic chromium salt, an inorganic chromium salt, a chromium coordination, and a chromium organometallic complex.
17. The catalyst system of claim 13 , wherein the chromium compound comprises one or more of chromium trichloride tris-tetrahydrofuran complex, (benzene)tricarbonyl chromium, chromium (III) octanoate, chromium (III) acetylacetonoate, chromium hexacarbonyl, and chromium (III) 2-ethylhexanoate.
18. The catalyst system of claim 13 , wherein the organoaluminum compound has a structure:
wherein R 11 , R 12 , and R 13 are each selected from a hydrogen atom and a (C 1 -C 20 ) hydrocarbyl group or a (C 1 -C 20 ) heterohydrocarbyl group.
19. The catalyst system of claim 13 , 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.
20. The catalyst system of claim 13 , wherein the catalyst system comprises the co-catalyst in an amount such that a molar ratio of aluminum to chromium is from 1 to 5000.