Process for producing .alpha.-olefin oligomer

• US 6,133,495 A
• Filed: 01/02/1998
• Issued: 10/17/2000
• Est. Priority Date: 03/14/1996
• Status: Expired due to Term

• Current Assignee: Mitsubishi Chemical Corporation (Mitsubishi Chemical Group Corp.)
• Original Assignee: Mitsubishi Chemical Corporation (Mitsubishi Chemical Group Corp.)
• Inventors: Aoshima, Takayuki, Nishimura, Sugio, Urata, Hisao
• Primary Examiner(s): GRIFFIN, WALTER DEAN
• Application Number:
  US08/952,746
• Time in Patent Office: 1,019 Days
• Field of Search: 585/512, 585/513, 585/527, 548/402, 548/564
• US Class Current: 585/513
• CPC Class Codes: C07C 2/30 containing metal-to-carbon bond; Metal hydrides
• CPC Class Codes: C07C 2/32 as complexes, e.g. acetyl-acetonates complexes of salts of acids of halogen C07C2/20
• CPC Class Codes: C07C 2531/02 containing organic compounds or metal hydrides
• CPC Class Codes: C07C 2531/14 of aluminium or boron
• CPC Class Codes: C07C 2531/22 Organic complexes
• CPC Class Codes: C08F 10/00 Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
• CPC Class Codes: C08F 4/69 Chromium, molybdenum, tungsten or compounds thereof

Abstract

A process for producing an α-olefin oligomer, comprising subjecting an α-olefin to oligomerization in a reaction solution containing a chromium-based catalyst produced by bringing at least a chromium compound (a), a pyrrole ring-containing compound (b), an alkyl aluminum compound (c) and a halogen-containing compound (d) into contact with each other, wherein the chromium-based catalyst is a catalyst produced by bringing the pyrrole ring-containing compound (b), the alkyl aluminum compound (c) and the halogen-containing compound (d) into contact with each other in a hydrocarbon and/or halogenated hydrocarbon solvent, and then bringing the resultant mixed solution into contact with the chromium compound (a); or a catalyst produced by bringing the chromium compound (a), the pyrrole ring-containing compound (b), the alkyl aluminum compound (c) and the halogen-containing compound (d) into contact with each other in a hydrocarbon and/or halogenated hydrocarbon solvent in the absence of α-olefin under such a condition that the concentration of the chromium compound (a) is adjusted to not more than 8×10^-3 mol/liter. In accordance with the present invention, an α-olefin oligomer such as 1-hexene can be produced from α-olefin such as ethylene with a high yield and a high selectivity.

Claims

1. A process for producing an α

-oligomer, comprising the steps of;

(1) preparing a reaction solution containing a chromium-based catalyst by bringing at least a chromium compound (a), a pyrrole ring-containing compound (b), an alkyl aluminum compound (c) and a halogen-containing compound (d) into contact with each other,

wherein the chromium-based catalyst is prepared by bringing the pyrrole ring-containing compound (b), the alkyl aluminum compound (c) and the halogen-containing compound (d) into contact with each other in a hydrocarbon solvent, halogenated hydrocarbon solvent or mixture thereof, and then bringing the mixed resultant solution into contact with the chromium compound (a) and thereafter

(2) contacting an α

-olefin with the catalyst solution prepared in step (1) and oligomerizing the α

-olefin.

2. A process according to claim 1, wherein the chromium-based catalyst is a catalyst prepared by bringing the pyrrole ring-containing compound (b), the alkyl aluminum compound (c) and the halogen-containing compound (d) into contact with each other in a hydrocarbon solvent, halogenated hydrocarbon solvent or mixture thereof in the absence of α

-olefin, and then bringing the mixed resultant solution into contact with the chromium compound (a).

3. A process according to claim 1, wherein the concentration of the chromium compound (a) in the resultant mixed solution is 1×

10^-7 to 3×

10^-2 mol/liter.

4. A process according to claim 1, wherein the chromium-based catalyst is preserved in an organic solvent containing unsaturated hydrocarbon, when the chromium-based catalyst produced is stored for a long period of time before used in the oligomerization of α

-olefin.

5. A process according to claim 4, wherein said chromium-based catalyst is preserved in an organic solvent containing unsaturated hydrocarbon in an amount of not less than 50 moles per mole of a chromium atom in the catalyst.

6. A process according to claim 4, wherein said chromium-based catalyst is preserved in an organic solvent containing unsaturated hydrocarbon in an amount of not less than 5% by weight.

7. A process according to claim 4, wherein said unsaturated hydrocarbon is an aromatic hydrocarbon having 6 to 12 carbon atoms.

8. A process according to claim 4, wherein said hydrocarbon solvent, halogenated hydrocarbon solvent or mixture thereof used for the production of the catalyst contains unsaturated hydrocarbon, and the chromium-based catalyst produced is preserved in the solvent as it is.

9. A process according to claim 1, wherein the oligomerization of α

-olefin is conducted by a continuous method or by a semi-batch method, and an additional amount of the halogen-containing compound (d) is supplied in the course of the reaction.

10. A process according to claim 9, wherein the chromium-based catalyst is a catalyst prepared by bringing the chromium compound (a) or the alkyl aluminum compound (c) into contact with at least one of the pyrrole ring-containing compound (b) and the halogen-containing compound (d) with each other before bringing the chromium compound (a) and the alkyl aluminum compound (c) into contact with each other.

11. A process according to claim 9, wherein the oligomerization of α

-olefin is conducted by a continuous method, and the additional amount of the halogen-containing compound (d) is supplied when the residence time of the catalyst in a reactor is not less than 5 minutes.

12. A process according to claim 9, wherein the oligomerization of α

-olefin is conducted by a semi-batch method, and the additional amount of the halogen-containing compound (d) is supplied when the residence time of the catalyst in a reactor is not less than 5 minutes.

13. A process according to claim 9, wherein an additional amount of the alkyl aluminum compound (c) is supplied in addition to the additional amount of the halogen-containing compound (d).

14. A process according to claim 9, wherein the halogen-containing compound (d) additionally supplied contains a halogen atom bonded to an element belonging to 13-Group or 14-Group of the Periodic Table.

15. A process according to claim 1, wherein said chromium compound (a) is a salt of chromium and β

-diketone, a salt of chromium and β

-keto-carboxylic acid or a salt of chromium and other carboxylic acid.

16. A process according to claim 1, wherein the halogen-containing compound (d) contains an element selected from the group consisting of those belonging to 3-Group, 4-Group, 6-Group (exclusive of chromium), 13-Group, 14-Group and 15-Group of the Periodic Table.

17. A process according to claim 1, wherein said α

-olefin subjected to the oligomerization is ethylene, and said α

-olefin oligomer contains 1-hexene as a main component.

18. A process for producing an α

-olefin oligomer, comprising the steps of;

(1) preparing a reaction solution containing a chromium-based catalyst produced by bringing at least a chromium compound (a), a pyrrole ring-containing compound (b), an alkyl aluminum compound (c) and a halogen-containing compound (d) into contact with each other,

wherein the chromium-based catalyst is prepared by bringing the chromium compound (a), the pyrrole ring-containing compound (b), the alkyl aluminum compound (c) and the halogen-containing compound (d) into contact with each other in a hydrocarbon solvent, halogenated hydrocarbon solvent or mixture thereof in the absence of α

-olefin under such a condition that the concentration of the chromium compound (a) in the resultant mixed solution is adjusted to not more than 8×

10^-3 mol/liter and thereafter,

(2) contacting an α

-olefin with the catalyst solution prepared in step (1) and oligomerizing the α

-olefin.

19. A process according to claim 18, wherein the concentration of the chromium compound (a) in the resultant mixed solution is 1×

10^-3 to 8×

10^-3 mol/liter.

20. A process according to claim 18, wherein the chromium-based catalyst is a catalyst prepared by bringing the pyrrole ring-containing compound (b), the alkyl aluminum compound (c) and the halogen-containing compound (d) into contact with each other, and then bringing the mixed resultant solution into contact with the chromium compound (a).

21. A process according to claim 18, wherein the chromium-based catalyst is a catalyst prepared by first bringing the chromium compound (a), the pyrrole ring-containing compound (b) and the halogen-containing compound (d) into contact with each other in the solvent to produce a reaction product of the pyrrole ring-containing compound (b) and the halogen-containing compound (d) in the form of a precipitate, and then adding the alkyl aluminum compound (c) to the reaction mixture.

22. A process according to claim 21, wherein the main component of the precipitate is a pyrrole derivative represented by the general formula (I):

##STR3## wherein R¹ to R⁴ are a hydrogen atom or a linear or branched hydrocarbon group having 1 to 20 carbon atoms, in which R³ and R⁴ may integrally form a ring;

X is a halogen atom;

M is an element selected from the group consisting of those belonging to 3-Group, 4-Group, 6-Group (exclusive of chromium), 13-Group, 14-Group and 15-Group of the Periodic Table;

m and n are numbers satisfying the relationships of 1≦

m≦

6, 0≦

n≦

5 and 2≦

m+n≦

6 with the proviso that the sum of m and n is identical to the valence of the element M;

n represents the number of Rs; and

R is a hydrogen atom or a linear or branched hydrocarbon group having 1 to 20 carbon atoms and when n is not less than 2, Rs may be the same or different.

23. A process according to claim 18, wherein the chromium-based catalyst is a catalyst prepared by first bringing the pyrrole ring-containing compound (b) and the halogen-containing compound (d) into contact with each other in the solvent to produce a reaction product of the pyrrole ring-containing compound (b) and the halogen-containing compound (d) in the form of a precipitate, and then adding, in turn, the chromium compound (a) and the alkyl aluminum compound (c) to the reaction mixture.

24. A process according to claim 23, wherein the main component of the precipitate is a pyrrole derivative represented by the general formula (I):

##STR4## wherein R¹ to R⁴ are a hydrogen atom or a linear or branched hydrocarbon group having 1 to 20 carbon atoms, in which R³ and R⁴ may integrally form a ring;

X is a halogen atom;

M is an element selected from the group consisting of those belonging to 3-Group, 4-Group, 6-Group (exclusive of chromium), 13-Group, 14-Group and 15-Group of the Periodic Table;

m and n are numbers satisfying the relationships of 1≦

m≦

6, 0≦

n≦

5 and 2≦

m+n≦

6 with the proviso that the sum of m and n is identical to the valence of the element M;

n represents the number of Rs; and

R is a hydrogen atom or a linear or branched hydrocarbon group having 1 to 20 carbon atoms and when n is not less than 2, Rs may be the same or different.

25. A process according to claim 18, wherein the chromium-based catalyst is a catalyst prepared by bringing a mixture obtained by preliminarily mixing the chromium compound (a) and the pyrrole ring-containing compound (b) together, into contact with a mixture obtained by preliminarily mixing the alkyl aluminum compound (c) and the halogen-containing compound (d) together.

26. A process according to claim 18, wherein the chromium-based catalyst is preserved in an organic solvent containing unsaturated hydrocarbon, when the chromium-based catalyst produced is stored for a long period of time before used in the oligomerization of α

-olefin.

27. A process according to claim 18, wherein the oligomerization of α

-olefin is conducted by a continuous method or by a semi-batch method, and an additional amount of the halogen-containing compound (d) is supplied in the course of the reaction.

28. A process according to claim 18, wherein said chromium compound (a) is a salt of chromium and β

-diketone, a salt of chromium and β

-keto-carboxylic acid or a salt of chromium and other carboxylic acid.

29. A process according to claim 18, wherein the halogen-containing compound (d) contains an element selected from the group consisting of those belonging to 3-Group, 4-Group, 6-Group (exclusive of chromium), 13-Group, 14-Group and 15-Group of the Periodic Table.

30. A process according to claim 18, wherein said α

-olefin subjected to the oligomerization is ethylene, and said α

-olefin oligomer contains 1-hexene as a main component.

31. A pyrrole derivative represented by the general formula (I):

##STR5## wherein R¹ to R⁴ are a hydrogen atom or a linear or branched hydrocarbon group having 1 to 20 carbon atoms, in which R³ and R⁴ may integrally form a ring;

X is a halogen atom;

M is an element selected from the group consisting of those belonging to 3-Group, 4-Group, 6-Group (exclusive of chromium), 13-Group, 14-Group and 15-Group of the Periodic Table;

m and n are numbers satisfying the relationships of 1≦

m≦

6, 0≦

n≦

5 and 2≦

m+n≦

6 with the proviso that the sum of m and n is identical to the valence of the element M;

n represents the number of Rs; and

R is a hydrogen atom or a linear or branched hydrocarbon group having 1 to 20 carbon atoms and when n is not less than 2, Rs may be the same or different.