Microbial process for the preparation of acetic acid as well as solvent for its extraction from the fermentation broth

• US 6,368,819 B1
• Filed: 03/07/2001
• Issued: 04/09/2002
• Est. Priority Date: 09/08/1998
• Status: Expired

• Current Assignee: Celanese International Corporation (Celanese Corporation), INEOS Bio Limited (Ineos AG)
• Original Assignee: Bioengineering Resources, Inc., Celanese International Corporation (Celanese Corporation)
• Inventors: Ko, Ching-Whan, Wikstrom, Carl V., Gaddy, James L., Clausen, Edgar C., Wade, Leslie E.
• Primary Examiner(s): Lilling, Herbert J.
• Application Number:
  US09/786,544
• Time in Patent Office: 398 Days
• Field of Search: 435/140, 435/42, 435/252.7, 435/170
• US Class Current: 435/42
• CPC Class Codes: C07C 211/07 containing one, two or three alkyl groups, each having the same number of carbon atoms in excess of three
• CPC Class Codes: C07C 51/44 by distillation
• CPC Class Codes: C07C 51/47 by solid-liquid treatment; by chemisorption
• CPC Class Codes: C07C 51/48 by liquid-liquid treatment
• CPC Class Codes: C07C 53/08 Acetic acid pyroligneous acid C10C; preparation of vinegar C12J
• CPC Class Codes: C12P 7/54 Acetic acid vinegar C12J

Abstract

A modified water-immiscible solvent useful in the extraction of acetic acid from aqueous streams is a substantially pure mixture of isomers of highly branched di-alkyl amines. This solvent is substantially devoid of mono-alkyl amines and alcohols. Solvent mixtures formed of such a modified solvent with a desired cosolvent, preferably a low boiling hydrocarbon which forms an azeotrope with water are useful in the extraction of acetic acid from aqueous gaseous streams. An anaerobic microbial fermentation process for the production of acetic acid employs such solvents, under conditions which limit amide formation by the solvent and thus increase the efficiency of acetic acid recovery. Methods for the direct extraction of acetic acid and the extractive fermentation of acetic acid also employ the modified solvents and increase efficiency of acetic acid production. Such increases in efficiency are also obtained where the energy source for the microbial fermentation contains carbon dioxide and the method includes a carbon dioxide stripping step prior to extraction of acetic acid in solvent.

Claims

1. A water-immiscible solvent/co-solvent mixture comprising:

(a) a water-immiscible solvent comprising greater than 50% by volume of a mixture of isomers of highly branched di-alkyl amines, and from about 0.01% to 20% by volume of mono-alkyl amines said solvent having a coefficient of distribution greater than 10; and

(b) at least 10% by volume of a non-alcohol co-solvent having a boiling point lower than the boiling point of said solvent (a),

wherein said mixture extracts acetic acid from aqueous streams.

2. The mixture according to claim 1 wherein said co-solvent is immiscible with water and readily separates therefrom, and has low toxicity to anaerobic acetogenic bacteria.

3. The mixture according to claim 1 wherein said co-solvent forms an azeotrope with water and acetic acid.

4. The mixture according to claim 1 wherein said co-solvent comprises a hydrocarbon having from 9 to 11 carbon atoms.

5. The mixture according to claim 1 wherein said solvent (a) contains greater than 80% by volume said di-alkyl amines and is reduced to less than about 1% by volume of low boiling compounds and mono-alkyl amines wherein said low boiling compounds boil at or below 115°

C. at 69.9 Torr.

6. The mixture according to claim 1 wherein said solvent (a) contains from about 1% to 10% by volume tri-alkyl amines.

7. The mixture according to claim 1, wherein said solvent (a) is produced by distilling from a solvent containing low boiling compounds, mono-alkyl amines, di-alkyl amines and tri-alkyl amines substantially all low boiling compounds and monoalkyl amines to improve acetic acid extractive capacity wherein said low boiling compounds boil at or below 115°

C. at 69.9 Torr.

8. The mixture according to claim 7, wherein said solvent (a) is produced by subjecting said distilled solvent to a second distillation to reduce substantially all tri-alkyl amines.

9. A process for obtaining acetic acid from an aqueous phase comprising acetic acid comprising the steps of:

(a) contacting the aqueous phase with the solvent/co-solvent mixture of claim 1;

(b) extracting acetic acid from said aqueous phase into the resulting solvent phase; and

(c) distilling acetic acid from said solvent phase under a temperature not exceeding 160°

C.

10. An anaerobic microbial fermentation process for the production of acetic acid, said process comprising the steps of:

(a) fermenting in a bioreactor an aqueous stream comprising an anaerobic acetogenic bacteria in a nutrient medium and a gas stream comprising at least one gas selected from the group consisting of (1) carbon monoxide, (2) carbon dioxide and hydrogen, (3) carbon monoxide, carbon dioxide and hydrogen; and

(4) carbon monoxide and hydrogen;

thereby producing a fermentation broth comprising acetic acid;

(b) separating said bacteria from other components in said broth to provide a substantially cell-free stream;

(c) continuously extracting acetic acid from said cell-free stream into a solvent phase by contacting said cell-free stream with a solvent mixture of claim 1; and

(d) continuously distilling from the product of (c) the acetic acid separately from the solvent phase under a temperature not exceeding 160°

C.;

wherein said extracting and distilling steps occur without substantially degrading said amine to an amide, thus enhancing the efficiency of production of acetic acid.

11. The process according to claim 10 wherein said separating step employs a centrifuge, a hollow fiber membrane, or a solid-liquid separation device.

12. The process according to claim 10 further comprising as step (e) recycling said solvent to the distillation device of step (d) and said cell-free stream to said bioreactor in step (a).

13. The process according to claim 10 wherein said distillation step occurs in a substantially oxygen-free vacuum.

14. The process according to claim 10 wherein step (d) further employs a vacuum between about 0.5 to about 10 psia.

15. The process according to claim 10 wherein said anaerobic bacteria is selected from the group consisting of Acetobacterium kivui, A. woodii, Butyribacterium methylotrophicum, Clostridium aceticum, C. acetobutylicum, C. formoaceticum, C. kluyveri, C. thermoaceticum, C. thermocellum, C. thermosaccharolyticum, Eubacterium limosum, Peptostreptococcus productus, and C. ljungdahlii, and mixtures thereof.

16. The process according to claim 15 wherein said C. ljungdahlii is selected from the strains consisting of:

PETC ATCC 55383, O-52 ATCC 55989, ERI2 ATCC 55380 and C-01 ATCC 55988, and mixtures thereof.

17. A method for enhancing the efficiency of acetic acid recovery from a fermentation broth comprising an aqueous stream containing an anaerobic acetogenic bacterium and nutrient medium, said bacterium having been fermented in the presence of a gas stream comprising at least one gas selected from the group consisting of (1) carbon monoxide, (2) carbon dioxide and hydrogen, (3) carbon monoxide, carbon dioxide and hydrogen;

and (4) carbon monoxide and hydrogen;

said method comprising contacting said stream with a solvent mixture of claim 1;

continuously extracting said acetic acid from said stream in said solvent mixture; and

distilling said acetic acid from said solvent at a distillation temperature not exceeding 160°

C. therefrom, without substantially degrading said amine to amide.

18. An anaerobic microbial fermentation process for the production of acetic acid, said process comprising the steps of:

(a) providing in a fermenter an anaerobic acetogenic bacterium in a nutrient mixture and a solvent mixture of claim 1 for a time sufficient to acclimate said bacteria to said solvent;

(b) introducing into said fermenter an aqueous stream comprising at least one gas selected from the group consisting of (1) carbon monoxide, (2) carbon dioxide and hydrogen, (3) carbon monoxide, carbon dioxide and hydrogen, and (4) carbon monoxide and hydrogen; and

producing a fermentation broth comprising said bacteria, nutrient medium, acetic acid, solvent and water;

(c) introducing said fermentation broth into a settling tank, wherein an aqueous phase containing said bacteria and nutrient medium settles to the bottom of said tank from the solvent phase which contains acetic acid, solvent and water, without filtration;

(d) continuously distilling from the solvent phase of (c) the acetic acid separately from the solvent phase under a temperature not exceeding 160°

C.;

wherein said distilling step occurs without substantially degrading said amine to an amide, thus enhancing the efficiency of acetic acid production.

19. The process according to claim 18 further comprising recycling said solvent and said aqueous phase containing said bacteria into said fermenter.

20. The process according to claim 19 wherein said distillation step occurs in a substantially oxygen-free vacuum.

21. The process according to claim 18 wherein step (d) further employs a vacuum between about 0.5 to about 10 psia.

22. The process according to claim 18 wherein said anaerobic bacteria is selected from the group consisting of Acetobacterium kivui, A. woodii, Butyribacterium methylotrophicum, Clostridium aceticum, C. acetobutylicum, C. formoaceticum, C. kluyveri, C. thermoaceticum, C. thermocellum, C. thermosaccharolyticum, Eubacterium limosum, Peptostreptococcus productus, and C. ljungdahlii, and mixtures thereof.

23. The process according to claim 22 wherein said C.ljungdahlii is selected from the strains consisting of PETC ATCC 55383, O-52 ATCC 55989, ERI2 ATCC 55380 and C-01 ATCC 55988, and mixtures thereof.

24. An anaerobic microbial fermentation process for the production of acetic acid, said process comprising the steps of:

(a) fermenting in a bioreactor an aqueous stream comprising a nutrient mixture with an anaerobic acetogenic bacteria and at least one gas selected from the group consisting of (1) carbon monoxide, (2) carbon dioxide and hydrogen, (3) carbon monoxide, carbon dioxide and hydrogen; and

(4) carbon monoxide and hydrogen;

thereby producing a broth comprising acetic acid, water, and bacterial cells;

(b) introducing into an extraction device containing either a continuous solvent phase or a continuous aqueous phase and having exits and entrances therefrom, (i) said broth with no cell separation and (ii) a solvent comprising a solvent mixture of claim 1, wherein a solvent phase containing acetic acid, solvent and water exits said extraction device separately from an aqueous phase comprising said bacteria and nutrient media;

(c) continuously distilling from the solvent phase of (b) the acetic acid and water separately from the solvent at a temperature not exceeding 160°

C.;

wherein said steps (b) and (c) occur without substantially degrading said amine to an amide, thus enhancing the efficiency of acetic acid production.

25. The process according to claim 24 wherein said step (b) comprises introducing said solvent into said extraction device in a flow concurrent or countercurrent to that of said broth.

26. The process according to claim 24 further comprising recycling said solvent and said aqueous phase containing said bacteria into said fermenter.

27. The process according to claim 24 wherein said distillation step occurs in a substantially oxygen-free vacuum.

28. The process according to claim 24 wherein step (c) further employs a vacuum between about 0.5 to about 10 psia.

29. The process according to claim 24 wherein said anaerobic bacteria is selected from the group consisting of Acetobacterium kivui, A. woodii, Butyribacterium methylotrophicum, Clostridium aceticum, C. acetobutylicum, C. formoaceticum, C. kluyveri, C. thermoaceticum, C. thermocellum, C. thermosaccharolyticum, Eubacterium limosum, Peptostreptococcus productus, and C. ljungdahlii, and mixtures thereof.

30. The process according to claim 29 wherein said C. ljungdahlii is selected from the strains consisting of PETC ATCC 55383, O-52 ATCC 55989, ERI2 ATCC 55380 and C-01 ATCC 55988, and mixtures thereof.

31. An anaerobic microbial fermentation process for the production of acetic acid, said process comprising the steps of:

(a) fermenting in a bioreactor an aqueous stream comprising at least one gas selected from the group consisting of (1) carbon monoxide, (2) carbon dioxide and hydrogen, (3) carbon monoxide, carbon dioxide and hydrogen; and

(4) carbon monoxide and hydrogen;

in a nutrient mixture with an anaerobic acetogenic bacteria, thereby producing a fermentation broth comprising acetic acid and dissolved carbon dioxide;

(b) removing said carbon dioxide from the fermentation broth prior to extraction;

(c) contacting said broth (b) with a solvent mixture comprising;

(i) a water-immiscible solvent comprising greater than 50% by volume of a mixture of isomers of highly branched di-alkyl amines, and from about 0.01% to 20% by volume of mono-alkyl amines said solvent having a coefficient of distribution greater than 10; and

(ii) at least 10% by volume of a non-alcohol co-solvent having a boiling point lower than the boiling point of said solvent (i);

wherein a solvent phase is formed and comprises acetic acid, said solvent and water; and

(d) continuously distilling acetic acid from said solvent phase.

32. The process according to claim 31 wherein said distilling step occurs at a temperature not exceeding 160°

C., without substantially degrading said amine to an amide, thus enhancing the efficiency of production of acetic acid.

33. The process according to claim 31 wherein said distillation step occurs in a substantially oxygen-free vacuum.

34. The process according to claim 32 wherein said distilling step further employs a vacuum between about 0.5 to about 10 psia.