Methods for oligomerizing olefins
The present invention provides a method of producing oligomers of olefins, comprising reacting olefins with a catalyst under oligomerization conditions. The catalyst can be the product of the combination of a chromium compound and a pyridyl amine or a heteroaryl-amine compound. In particular embodiments, the catalyst compound can be used to trimerize or tetramerize ethylene to 1-hexene, 1-octene, or mixtures of 1-hexene and 1-octene.
1. A composition comprising:
(1) a ligand characterized by the following general formula:
wherein R 1 and R 20 are each independently selected from the group consisting of hydrogen and optionally substituted methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, decyl and dodecyl groups;
T is a bridging group of the general formula —(T′R 2 R 3 )—, where T′ is selected from the group consisting of carbon and silicon, R 2 and R 3 are independently selected from the group consisting of hydrogen, halogen, and optionally substituted alkyl, heteroalkyl, aryl, heteroaryl, alkoxy, aryloxy, silyl, boryl, phosphino, amino, alkylthio, arylthio, cyclo-alkyl, and combinations thereof, provided that two or more R 2 and/or R 3 groups may be joined together to form one or more optionally substituted ring systems having from 3-50 non-hydrogen atoms;
R 4 , R 5 , R 6 and R 7 are independently selected from the group consisting of hydrogen, halogen, nitro, and optionally substituted alkyl, heteroalkyl, aryl, heteroaryl, alkoxy, aryloxy, silyl, boryl, phosphino, amino, alkylthio, arylthio, and combinations thereof, and optionally two or more R 1 , R 20 , R 2 , R 3 , R 4 , R 5 , R 6 and R 7 groups may be joined to form one or more optionally substituted ring systems
(2) a metal precursor compound characterized by the general formula Cr(L) n where each L is independently selected from the group consisting of halide, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, heteroalkyl, substituted heteroalkyl heterocycloalkyl, substituted heterocycloalkyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl, alkoxy, aryloxy, hydroxy, boryl, silyl, amino, amine, hydrido, allyl, diene, seleno, phosphino, phosphine, ether, thioether, carboxylates, thio, 1,3-dionates, oxalates, carbonates, nitrates, sulfates, ethers, thioethers and combinations thereof, wherein two or more L groups may be combined in a ring structure having from 3 to 50 non-hydrogen atoms; n is 1, 2, 3, 4, 5, or 6; and
(3) optionally, one or more activators.
2. The composition of claim 1 , wherein R 7 is selected from the group consisting of optionally substituted aryl and heteroaryl.
3. The composition of claim 1 , wherein R 3 is selected from the group consisting of hydrogen and optionally substituted alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, silyl and combinations thereof.
4. The composition of claim 1 , wherein R 5 is selected from the group consisting of —CF 3 , H, F, Cl, —N(Me) 2 and —OR, wherein R is an optionally substituted alkyl group, an optionally substituted benzyl group or an optionally substituted aryl group.
5. The composition of claim 1 , wherein T' is carbon; R 2 and R 3 are independently selected from the group consisting of hydrogen, optionally-substituted alkyl, aryl, cyclo-alkyl and combinations thereof; R 20 is hydrogen; and R 1 is optionally substituted alkyl.
6. The composition of claim 5 , wherein R 4 , R 5 , and R 6 are hydrogen; and R 7 is optionally substituted aryl.
7. The composition of claim 1 , wherein R 1 and R 20 are independently an optionally substituted alkyl; T' is carbon; R 2 and R 3 are each independently hydrogen, cyclo-alkyl, or optionally substituted alkyl; and R 7 is aromatic with at least one C-H bond.
8. The composition of claim 1 , wherein the activator is an alumoxane, which mat optionally be used in any combination with group 13 reagents, divalent metal reagents, alkali metal reagents or combinations thereof.
9. The composition of claim 1 , wherein the activator is selected from the group consisting of modified methylaluminoxane (MMAO), methylaluminoxane (MAO), trimethylaluminum (TMA), triisobutyl aluminum (TIBA), diisobutylaluminumhydride (DIBAL), polymethylaluminoxane-IP (PMAO), triphenylcarbonium tetrakis(perfluorophenyl)borate, N,N-dimethyl-anilinium tetrakis(perfluorophenyl)borate N,N-di(n-decyl)- 4 -n-buty-anilinium tetrakis(perfluorophenyl)borate, and mixtures thereof.