Acid/salt separation

Patent metadata

Field	Value
Publication number	US-10508069-B2
Application number	US-201816030415-A
Country	US
Kind code	B2
Filing date	Jul 9, 2018
Priority date	Aug 16, 2011
Publication date	Dec 17, 2019
Grant date	Dec 17, 2019

Abstract

The invention provides a method for preparing a carboxylic acid, which method includes the steps of providing magnesium carboxylate, wherein the carboxylic acid corresponding with the carboxylate has a solubility in water at 20° C. of 80 g/100 g water or less; acidifying the magnesium carboxylate with HCl, thereby obtaining a solution comprising carboxylic acid and magnesium chloride (MgCl 2 ); optionally a concentration step, wherein the solution comprising carboxylic acid and MgCl 2 is concentrated; precipitating the carboxylic acid from the solution comprising the carboxylic acid and MgCl 2 , thereby obtaining a carboxylic acid precipitate and a MgCl 2 solution.

First claim

The invention claimed is:

1. A method for the recovery of a carboxylic acid that is not succinic acid, the method comprising:
providing magnesium carboxylate, wherein the carboxylic acid corresponding with the carboxylate has a solubility in water at 20° C. of 80 g/100 g water or less;
acidifying the magnesium carboxylate with hydrogen chloride (HCl), thereby obtaining a solution comprising carboxylic acid and magnesium chloride (MgCl 2 );
precipitating the carboxylic acid from the solution comprising the carboxylic acid and MgCl 2 , thereby obtaining a carboxylic acid precipitate and a MgCl 2 solution; and
thermally decomposing the MgCl 2 solution at a temperature of at least 300° C., thereby decomposing the MgCl 2 to magnesium oxide (MgO) and HCl.

2. The method according to claim 1 , wherein the carboxylic acid has a solubility in water at 20° C. that is lower than that of MgCl 2 .

3. The method according to claim 1 , wherein the carboxylic acid has a solubility in water of less than 60 g/100 g water at 20° C.

4. The method according to claim 3 , wherein the carboxylic acid has a solubility in water of less than 30 g/100 g water at 20° C.

5. The method according to claim 1 , wherein the carboxylic acid is selected from the group consisting of adipic acid, itaconic acid, 2,5-furandicarboxylic acid, fumaric acid, maleic acid, glutaric acid, malonic acid, oxalic acid and fatty acids having more than 10 carbon atoms.

6. The method according to claim 1 , wherein the magnesium carboxylate is provided in dissolved form, as part of an aqueous solution or suspension obtained in a fermentation process.

7. The method according to claim 6 , wherein the aqueous solution or suspension obtained in a fermentation process further comprises the carboxylic acid.

8. The method according to claim 6 , wherein the magnesium carboxylate is directly obtained in dissolved form during a fermentation process through neutralization of carboxylic acid obtained as a fermentation product with a magnesium base.

9. The method according to claim 6 , wherein the magnesium carboxylate is provided in dissolved form as part of an aqueous suspension obtained in a fermentation process by neutralization of carboxylic acid obtained as a fermentation product with a magnesium base, wherein the aqueous suspension comprises up to 10 wt. % solids.

10. The method according to claim 6 , wherein the magnesium carboxylate is provided in dissolved form as part of an aqueous suspension obtained in a fermentation process by neutralization of carboxylic acid obtained as a fermentation product with a magnesium base and wherein, in the aqueous suspension, at least 95 wt. % of the magnesium carboxylate is in dissolved form.

11. The method according to claim 6 , wherein the aqueous suspension consists of dissolved magnesium carboxylate and insoluble biomass.

12. The method according to claim 1 comprising:
providing magnesium carboxylate in dissolved form, as part of an aqueous solution or suspension obtained in a fermentation process, wherein the carboxylic acid corresponding with the carboxylate has a solubility in water at 20° C. of 80 g/100 g water or less; and, obtaining solid magnesium carboxylate from the solution or suspension and acidifying the magnesium carboxylate with hydrogen chloride (HCl), thereby obtaining a solution comprising carboxylic acid and magnesium chloride (MgCl 2 ).

13. The method according to claim 12 , wherein the solid magnesium carboxylate is obtained in crystalline form and is optionally re-dissolved in water to form an aqueous solution prior to acidifying.

14. The method according to claim 12 , wherein the solid magnesium carboxylate is obtained as a cake following a solid-liquid separation.

15. The method according to claim 6 , wherein the aqueous solution or aqueous suspension comprises at least 10 wt. %, magnesium carboxylate, based on the total weight of the solution or suspension and wherein the solution comprising the carboxylic acid and MgCl 2 comprises at least 5 wt. % MgCl 2 , based on the total weight of the solution comprising carboxylic acid.

16. The method according to claim 15 , wherein the aqueous solution or aqueous suspension comprises between 10 and 50 wt. %, magnesium carboxylate, based on the total weight of the solution or suspension.

17. The method according to claim 15 , wherein the aqueous solution comprises the maximum concentration of magnesium carboxylate as determined by the solubility of the magnesium carboxylate up to a maximum temperature of 75° C.

18. The method according to claim 1 further comprising an intermediate concentration step between the acidification and precipitation steps, wherein the solution comprising carboxylic acid and MgCl 2 is concentrated.

19. The method according to claim 18 , wherein the solution comprising the carboxylic acid and MgCl 2 is concentrated to a carboxylic acid concentration that is equal or up to 5 g/L lower than the saturation point of the carboxylic acid.

20. The method according to claim 18 , wherein the solution comprising the carboxylic acid and MgCl 2 is concentrated to a carboxylic acid concentration that is equal or up to 10 g/L lower than the saturation point of the carboxylic acid.

21. The method according to claim 1 , wherein acidifying the magnesium carboxylate and precipitating the carboxylic acid thus formed are conducted in one step.

22. The method according to claim 1 , wherein the acidifying the magnesium carboxylate is with an excess of hydrogen chloride (HCl), thereby obtaining a solution comprising carboxylic acid and magnesium chloride (MgCl 2 ).

23. The method according to claim 22 , wherein the precipitating of the carboxylic acid from the solution comprising the carboxylic acid and MgCl 2 , obtains a carboxylic acid precipitate and a MgCl 2 solution having a pH of from 1 to 4.

24. The method according to claim 1 , wherein the acidification comprises either bringing the magnesium carboxylate in solid form, suspension or solution into contact with an aqueous HCl solution or bringing a magnesium carboxylate solution or suspension into contact with HCl gas.

25. The method according to claim 24 , wherein magnesium carboxylate is acidified with an aqueous HCl solution.

26. The method according to claim 25 , wherein the aqueous HCl solution comprises at least 5 wt. % HCl.

27. The method according to claim 1 , wherein the MgCl 2 solution is subjected to a second precipitation step to recover at least part of the carboxylic acid remaining in the MgCl 2 solution obtained in the first precipitation step.

28. The method according to claim 27 comprising an intermediate concentration step between the acidification and the precipitation steps, wherein the solution comprising carboxylic acid and MgCl 2 is concentrated and further wherein the concentrated MgCl 2 solution is subjected to a second precipitation step to recover at least part of the carboxylic acid remaining in the MgCl 2 solution obtained in the first precipitation step.

29. The method according to claim 27 , wherein the second precipitation is conducted by cooling and/or concentrating the MgCl 2 solution.

30. The method according to claim 27 , wherein the second precipitation is conducted by cooling the MgCl 2 solution from a temperature of at least 30° C. to a temperature less than 25° C.

Assignees

• Purac Biochem Bv

Inventors

• De Haan André Banier
• Van Breugel Jan
• Van Der Weide Paulus Loduvicus Johannes
• Jansen Peter Paul
• VIDAL LANCIS José Maria
• Cerdà Baró Agustin

Classifications

• C01B7/035

  Preparation of hydrogen chloride from chlorides · CPC title

• C01F5/10

  by thermal decomposition of magnesium chloride with water vapour · CPC title

• C07D307/60

  Two oxygen atoms, e.g. succinic anhydride · CPC title

• C07C51/02 Primary

  from salts of carboxylic acids · CPC title

• C01F5/30

  Chlorides · CPC title