Method for oligomerization of ethylene

Patent metadata

Field	Value
Publication number	US-9896392-B2
Application number	US-201314414403-A
Country	US
Kind code	B2
Filing date	Jun 5, 2013
Priority date	Jul 10, 2012
Publication date	Feb 20, 2018
Grant date	Feb 20, 2018

Abstract

The present invention relates to a method for oligomerization of ethylene, comprising the steps:
a) feeding ethylene, solvent and a catalyst composition comprising catalyst and cocatalyst into a reactor, b) oligomerizing ethylene in the reactor, c) discharging a reactor effluent comprising linear alpha-olefins including 1-butene, solvent, unconsumed ethylene dissolved in the reactor effluent, and catalyst composition from the reactor, d) separating ethylene and 1-butene collectively from the remaining reactor effluent, and e) recycling at least a part of the ethylene and the 1-butene separated in step d) into the reactor.

First claim

What is claimed is:

1. A method for oligomerization of ethylene, comprising the steps:
a) feeding ethylene, solvent and a catalyst composition comprising catalyst and cocatalyst into a reactor,
b) oligomerizing ethylene in the reactor,
c) discharging a reactor effluent comprising linear alpha-olefins including C 6+ linear alpha olefins and 1-butene, solvent, unconsumed ethylene dissolved in the reactor effluent, and catalyst composition from the reactor,
d) separating ethylene and 1-butene collectively from the remaining reactor effluent comprising the C 6+ linear alpha olefins, and
e) recycling at least a part of the ethylene and the 1-butene separated in step d) into the reactor; and
wherein a constant 1-butene content is in the reactor.

2. Method according to claim 1 , wherein the recycling stream of ethylene and 1-butene of step e) is purged at least partly by a purge stream.

3. The method according to claim 1 , wherein step b) is carried out at a temperature of 10-100° C. and/or a pressure of about 10-100 bar.

4. The method according to claim 1 , wherein additional 1-butene is fed into the reactor, from an external source at an initial start-up period of the method for oligomerization.

5. The method according to claim 1 , wherein the separation of step d) is carried out at a pressure below reaction pressure of step b).

6. The method according to claim 1 , wherein ethylene and 1-butene are recycled into the reactor in liquid form.

7. The method according to claim 1 , which is a trimerisation.

8. The method according to claim 1 , wherein the catalyst composition comprises a catalyst comprising a chromium compound and a ligand of the general structure (A) R 1 R 2 P—N(R 3 )—P(R 4 )—N(R 5 )—H or (B) R 1 R 2 P—N(R 3 )—P(R 4 )—N(R 5 )—PR 6 R 7 , wherein R 1 -R 7 are independently selected from halogen, amino, trimethylsilyl, C 1 -C 10 -alkyl, C 6 -C 20 aryl or any cyclic derivatives of (A) and (B), wherein at least one of the P or N atoms of the PNPN-unit or PNPNP-unit is a member of a ring system, the ring system being formed from one or more constituent compounds of structures (A) or (B) by substitution.

9. The method according to claim 8 , wherein the chromium compound is selected from organic or inorganic salts, coordination complexes and organometallic complexes of Cr(II) or Cr(III).

10. The method according to claim 1 , wherein the co-catalyst is selected from trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutyl-aluminum, ethylaluminumsesquichloride, diethylaluminumchloride, ethylaluminumdichloride, methylaluminoxane (MAO) or mixtures thereof.

11. The method according to claim 1 , wherein the catalyst composition additionally comprises a modifier containing organic or inorganic halide.

12. The method according to claim 8 , wherein the ligand is selected from Ph 2 P—N(i-Pr)—P(Ph)—N(i-Pr)—H, Ph 2 P—N(i-Pr)—P(Ph)—N(Ph)-H, Ph 2 P—N(i-Pr)—P(Ph)—N(tert-butyl)-H and Ph 2 P—N(i-Pr)—P(Ph)—N(CH(CH 3 )(Ph))—H.

13. The method according to claim 1 , wherein the solvent is selected from aromatic hydrocarbons, straight chain and cyclic aliphatic hydrocarbons, and ethers.

14. The method according to claim 13 , wherein the solvent is selected from toluene, benzene, ethylbenzene, cumene, xylenes, mesitylene, hexane, octane, cyclohexane, methylcyclohexane, diethylether, tetrahydrofurane, and mixtures thereof.

15. The method according to claim 13 , wherein the solvent is toluene.

16. The method according to claim 1 , wherein the amount of 1-butene in the reactor is at least 5 percent, based on the total weight of liquids in the reactor.

17. The method according to claim 1 , wherein the amount of 1-butene in the reactor is at least 10 percent, based on the total weight of liquids in the reactor.

18. The method according to claim 1 , wherein the amount of 1-butene in the reactor is at least 25 percent, based on the total weight of liquids in the reactor.

19. The method according to claim 8 , wherein the chromium compound is CrCl 3 (THF) 3 , Cr(III)acetyl acetonate, Cr(III)octanoate, chromium hexacarbonyl, Cr(III)-2-ethylhexanoate, benzene(tricarbonyl)-chromium or Cr(III)chloride.

20. The method according to claim 1 , wherein the amount of 1-butene in the reactor is at least 1 weight percent and up to 30 weight percent, based on the total weight of liquids in the reactor.

Assignees

• Saudi Basic Ind Corp
• Linde Ag

Inventors

• Meiswinkel Andreas
• Mueller Wolfgang
• Woehl Anina
• Harff Marco
• Bolt Heinz
• Hofmann Karl Heinz
• Zander Hans Jorg
• Wellenhofer Anton
• Iliyas Abduljelil
• Khurram Shehzada
• Azam Shahid
• Al Qahtani Abdullah

Classifications

• C07C11/107

  with six carbon atoms · CPC title

• C08F4/69

  Chromium, molybdenum, tungsten or compounds thereof · CPC title

• C07C2531/24

  Phosphines · CPC title

• C07C2/36 Primary

  as phosphines, arsines, stilbines or bismuthines · CPC title

• B01J31/143

  of aluminium · CPC title