Acid/salt separation

Patent metadata

Field	Value
Publication number	US-10017446-B2
Application number	US-201615378830-A
Country	US
Kind code	B2
Filing date	Dec 14, 2016
Priority date	Aug 16, 2011
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

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 preparing a carboxylic acid, comprising:
providing an aqueous solution or suspension of 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 an excess of hydrogen chloride (HCl), thereby obtaining a solution comprising carboxylic acid and magnesium chloride (MgCl 2 ); and
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, wherein
the carboxylic acid is selected from the group consisting of adipic acid, itaconic acid, 2,5-furandicarboxylic acid, fumaric acid, oxalic acid, maleic acid, glutaric acid, malonic acid, and fatty acids having more than 10 carbon atoms,
the aqueous solution or aqueous suspension comprises at least 10 wt. % magnesium carboxylate, based on the total weight of the solution or suspension, and
the solution comprising the carboxylic acid and MgCl 2 comprises at least 5 wt. % of magnesium chloride, based on the total weight of the solution.

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 1 , wherein magnesium carboxylate is provided in dissolved form, as part of an aqueous solution or as part of an aqueous suspension obtained in a fermentation process.

5. The method according to claim 1 , 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.

6. The method according to claim 1 , wherein said magnesium carboxylate is provided in dissolved form as part of an aqueous suspension obtained in a fermentation process by neutralization of carboxylic acid with a magnesium base and wherein, in said aqueous suspension, at least 95 wt. % of said magnesium carboxylate is in dissolved form.

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

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

9. The method according to claim 1 , wherein magnesium carboxylate is acidified with an HCl solution.

10. 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.

11. The method according to claim 10 , wherein the second precipitation is conducted by cooling and/or concentrating the MgCl 2 solution.

12. The method according to claim 10 , wherein additional MgCl 2 is added to the MgCl 2 solution prior to the second precipitation.

13. The method according to claim 1 , 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.

14. The method according to claim 1 , wherein the magnesium carboxylate is obtained in a fermentation process, which process comprises a purification step, wherein magnesium carboxylate is crystallized from the fermentation broth and then dissolved in water to form an aqueous solution.

15. The method according to claim 1 , further comprising:
subjecting the MgCl 2 solution to a thermal decomposition step at temperatures of at least 300° C., thereby decomposing the MgCl 2 to magnesium oxide (MgO) and HCl;
dissolving the HCl formed in the thermal decomposition step in water, thereby obtaining a HCl solution; and
bringing the MgO in contact with water, thereby obtaining Mg(OH) 2 , which Mg(OH) 2 is optionally recycled for use in a fermentation process.

16. The method according to claim 15 , wherein thermal decomposition is conducted using a spray roaster.

17. The method according to claim 15 , wherein the thermal decomposition is conducted at a pressure of ranging from 0.1-10 bar.

18. The method according to claim 15 , wherein the thermal decomposition is conducted at a temperature ranging from 300-450° C.

19. The method according to claim 15 , wherein Mg(OH) 2 is converted to MgCO 3 , which is then used as a neutralizing agent in a fermentation process.

20. The method according to claim 15 , wherein thermal decomposition is conducted by spraying the MgCl 2 solution into contact with a stream of hot gas.

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 Agustín

Classifications

• C01B7/035

  Preparation of hydrogen chloride from chlorides · CPC title

• C07D307/60

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

• C07C51/02 Primary

  from salts of carboxylic acids · CPC title

• C07C51/42

  Separation; Purification; Stabilisation; Use of additives · CPC title

• C01F5/30

  Chlorides · CPC title