# US 11,299,447 B2 · Method for isolating a carboxylic acid from an aqueous solution > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,299,447 B2 - Document ID: US11299447B2 - Status: Granted - Kind: B2 - Application number: 14/366,628 - Filed: 2012-12-21 - Published: 2015-01-01 - Granted: 2022-04-12 - Earliest claimed: 2011-12-23 - Assignees: Purac Biochem B.V. - Applicants: Purac Biochem BV - Inventors: André Banier De Haan; Jan Van Krieken; Tanja Ðekic {hacek over (Z)}ivkovic - Web page: https://patentgrep.com/patent/US11299447B2 ## CPC - C07C 51/48: by liquid-liquid treatment - B01D 11/04: of solutions which are liquid - C07C 51/412: {by conversion of the acids, their salts, esters or anhydrides with the same carboxylic acid part} - C12P 7/56: Lactic acid - B01D 11/0426: {Counter-current multistage extraction towers in a vertical or sloping position} - C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) - C12P: FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE {(brewing of beer C12C; producing vinegar C12J; producing specific peptides or proteins C07K; producing enzymes C12N9/00; DNA or RNA concerning genetic engineering, vectors, e.g. plasmids, or their isolation, preparation or purification C12N15/00; measuring or testing processes involving enzymes or microorganisms C12Q; measuring or testing processes involving nucleic acid amplification reactions C12Q1/6844; fermentation processes to form a food composition, A21 or A23; compounds in general, see the relevant compound class, e.g. C01, C07)} ## Abstract A method for manufacturing carboxylic acid that includes the following steps is provided. First, subjecting an aqueous mixture, including carboxylic acid and at least 5 wt. % dissolved magnesium chloride, to a forward extraction step using a first organic liquid, including an organic solvent, the organic solvent being selected from the group of C5+ ketones, thereby obtaining an organic carboxylic acid solution and an aqueous waste liquid including magnesium chloride. Second, subjecting the organic carboxylic acid solution to a back extraction step wherein the carboxylic acid is extracted from the organic carboxylic acid solution into an aqueous liquid, thereby obtaining an aqueous carboxylic acid solution and a second organic liquid. Third, subjecting the aqueous waste liquid including magnesium chloride derived from the forward extraction to a thermal decomposition step at a temperature of at least 300° C., thereby decomposing the magnesium chloride to magnesium oxide and HCl. ## Claims ### Claim 1 Method for the recovery of carboxylic acid, the method comprising the steps of: a) subjecting an aqueous mixture comprising carboxylic acid and at least 5 wt. % dissolved magnesium chloride, based on the total weight of water and dissolved material in the aqueous mixture to a forward extraction step, wherein the aqueous mixture subjected to the forward extraction step has a pH of 2 or lower, where the carboxylic acid is extracted from the aqueous mixture into a first organic liquid comprising at least 90% of an organic solvent, the organic solvent being selected from the group of C5-C8 ketones, to obtain an organic carboxylic acid solution and an aqueous waste liquid comprising magnesium chloride, b) subjecting the organic carboxylic acid solution to a back extraction step where the carboxylic acid is extracted from the organic carboxylic acid solution into an aqueous liquid to obtain an aqueous carboxylic acid solution and a second organic liquid; and c) subjecting the aqueous waste liquid comprising magnesium chloride obtained in the forward extraction to a thermal decomposition step at a temperature of at least 300° C. to decompose the magnesium chloride to magnesium oxide and HCl; wherein the carboxylic acid is at least one member selected from the group consisting of: glycolic acid; butyric acid; valeric acid; succinic acid; propionic acid; 3-hydroxypropionic acid; 2-hydroxybutyric acid; 3-hydroxybutyric acid; 4-hydroxybutyric acid; citric acid; fumaric acid; itaconic acid; adipic acid; acrylic acid; levulinic acid; maleic acid; 2,5-furandicarboxylic acid; mandelic acid; malic acid; and tartaric acid. ### Claim 2 (depends on 1) Method according to claim 1, wherein the aqueous mixture comprising carboxylic acid and the at least 5 wt. % dissolved magnesium chloride of step a) is obtained by: subjecting a carbon source to a fermentation step to form a carboxylic acid, which fermentation step comprises the steps of fermenting a carbon source by means of a micro-organism in a fermentation broth to form carboxylic acid and neutralizing at least part of the carboxylic acid by adding a magnesium base selected from magnesium oxide and magnesium hydroxide to obtain a magnesium carboxylate; and subjecting the magnesium carboxylate to an acidification step where the magnesium carboxylate is contacted with HCl in an aqueous environment to form an aqueous mixture comprising carboxylic acid and magnesium chloride. ### Claim 3 (depends on 1) Method according to claim 1, wherein the aqueous mixture subjected to the forward extraction step comprises at least 15 wt. % dissolved magnesium chloride, based on the total weight of water and dissolved material in the aqueous mixture. ### Claim 4 (depends on 1) Method according to claim 1, wherein said first organic liquid comprises at least 95 wt. % of said organic solvent. ### Claim 5 (depends on 1) Method according to claim 1, wherein the carboxylic acid is selected from the group consisting of: propionic acid; acrylic acid; butyric acid; and valeric acid. ### Claim 6 (depends on 1) Method according to claim 1, wherein said first organic liquid used in the extraction step a) comprises substantially no extractants, said extractants being compounds which form a complex with the carboxylic acid to be extracted. ### Claim 7 (depends on 1) Method according to claim 1, wherein the organic liquid is essentially free of amines, ethers, and alcohols, which means that these compounds, if present at all, are each present in an amount of less than 2 wt. % calculated on the weight of the organic liquid. ### Claim 8 (depends on 1) Method according to claim 1, wherein the aqueous mixture subjected to the forward extraction step has a pH of 0-1. ### Claim 9 (depends on 1) Method according to claim 1, wherein the aqueous mixture comprising carboxylic acid and magnesium chloride obtained from the acidification step is subjected to a concentration step comprising concentrating the aqueous mixture prior to extraction to a dissolved salt concentration of at least 5 wt. %, based on the total weight of water and dissolved material in the aqueous mixture. ### Claim 10 (depends on 2) Method according to claim 2, wherein at least part of the HCl from the thermal decomposition step c) is recycled to the acidification step after having been dissolved in water to obtain a HCl-containing solution. ### Claim 11 (depends on 2) Method according to claim 2, wherein the magnesium oxide formed in the thermal decomposition step c) is converted to magnesium hydroxide, which is added as magnesium base to the fermentation step. ### Claim 12 (depends on 2) Method according to claim 2, wherein at least part of the magnesium oxide formed in the thermal decomposition step c) is recycled to the fermentation step, in the form of MgO or after conversion into magnesium hydroxide. ### Claim 13 (depends on 2) Method according to claim 2, wherein at least part of the HCl from the thermal decomposition step c) is recycled to the acidification step. ### Claim 14 (depends on 1) Method according to claim 1, wherein the carboxylic acid is at least one member selected from the group consisting of: succinic acid; propionic acid; 3-hydroxypropionic acid; citric acid; fumaric acid; itaconic acid; adipic acid; acrylic acid; levulinic acid; maleic acid; 2,5-furandicarboxylic acid; mandelic acid; malic acid; tartaric acid; 2-hydroxybutyric acid; 3-hydroxybutyric acid; and 4-hydroxybutyric acid. ### Claim 15 (depends on 1) Method according to claim 1, wherein the carboxylic acid is at least one member selected from the group consisting of: succinic acid; propionic acid; 3-hydroxypropionic acid; citric acid; 2-hydroxybutyric acid; 3-hydroxybutyric acid; and 4-hydroxybutyric acid. ### Claim 16 (depends on 1) Method according to claim 1, wherein said first organic liquid used in the extraction step a) comprises substantially no amine extractants, said amine extractants being amine compounds which form a complex with the carboxylic acid to be extracted. ### Claim 17 (depends on 1) Method according to claim 1, wherein said first organic liquid comprises at least 99 wt. % of said organic solvent. ### Claim 18 (depends on 1) Method according to claim 1, wherein the aqueous mixture subjected to the forward extraction step comprises at least 20 wt. % dissolved magnesium chloride, based on the total weight of water and dissolved material in the aqueous mixture. ### Claim 19 (depends on 1) Method according to claim 1, wherein the aqueous mixture subjected to the forward extraction step comprises at least 25 wt. % dissolved magnesium chloride, based on the total weight of water and dissolved material in the aqueous mixture. ### Claim 20 (depends on 13) Method according to claim 13, wherein said HCl is recycled to the acidification step in gaseous form. ### Claim 21 (depends on 2) Method according to claim 2, wherein said acidification step is conducted on a mixture of carboxylic acid and magnesium carboxylate. ### Claim 22 Method for the recovery of carboxylic acid, said method comprising the steps of: a) subjecting an aqueous mixture comprising carboxylic acid and at least 5 wt. % dissolved magnesium chloride, based on the total weight of water and dissolved material in the aqueous mixture to a forward extraction step where the carboxylic acid is extracted from the aqueous mixture into a first organic liquid comprising at least 90 wt. % of an organic solvent, the organic solvent being selected from the group of C5-8 ketones, thereby obtaining an organic carboxylic acid solution and an aqueous waste liquid comprising magnesium chloride; b) subjecting the organic carboxylic acid solution to a back extraction step where the carboxylic acid is extracted from the organic carboxylic acid solution into an aqueous liquid to obtain a second organic liquid and an aqueous carboxylic acid solution whose concentration of carboxylic acids is higher than that of the aqueous mixture comprising carboxylic acid; and c) subjecting the aqueous waste liquid comprising magnesium chloride obtained in the forward extraction to a thermal decomposition step at a temperature of at least 300° C. to decompose the magnesium chloride to magnesium oxide and HCl, wherein the first organic liquid used in the extraction step a) comprises substantially no amine extractants, said amine extractants being amine compounds which form a complex with the carboxylic acid to be extracted. ### Claim 23 Method for the recovery of carboxylic acid, said method comprising the steps of: a) subjecting an aqueous mixture comprising carboxylic acid and at least 5 wt. % dissolved magnesium chloride, based on the total weight of water and dissolved material in the aqueous mixture to a forward extraction step where the carboxylic acid is extracted from the aqueous mixture into a first organic liquid comprising at least 90 wt. % of an organic solvent, the organic solvent being selected from the group of C5-8 ketones, thereby obtaining an organic carboxylic acid solution and an aqueous waste liquid comprising magnesium chloride; b) subjecting the organic carboxylic acid solution to a back extraction step where the carboxylic acid is extracted from the organic carboxylic acid solution into an aqueous liquid to obtain a second organic liquid and an aqueous carboxylic acid solution whose concentration of carboxylic acids is higher than that of the aqueous mixture comprising carboxylic acid; and c) subjecting the aqueous waste liquid comprising magnesium chloride obtained in the forward extraction to a thermal decomposition step at a temperature of at least 300° C. to decompose the magnesium chloride to magnesium oxide and HCl, wherein the first organic liquid used in the extraction step a) is essentially free of amines, ethers, and alcohols, which means that these compounds, if present at all, are each present in an amount of less than 2 wt. %, calculated on the weight of the first organic liquid. ### Claim 24 (depends on 22) The method according to claim 22, wherein the carboxylic acid is at least one member selected from the group consisting of: glycolic acid; butyric acid; valeric acid; succinic acid; propionic acid; 3-hydroxypropionic acid; 2-hydroxybutyric acid; 3-hydroxybutyric acid; 4-hydroxybutyric acid; citric acid; fumaric acid; itaconic acid; adipic acid; acrylic acid; levulinic acid; maleic acid; 2,5-furandicarboxylic acid; mandelic acid; malic acid; and tartaric acid. ### Claim 25 (depends on 23) The method according to claim 23, wherein the carboxylic acid is at least one member selected from the group consisting of: glycolic acid; butyric acid; valeric acid; succinic acid; propionic acid; 3-hydroxypropionic acid; 2-hydroxybutyric acid; 3-hydroxybutyric acid; 4-hydroxybutyric acid; citric acid; fumaric acid; itaconic acid; adipic acid; acrylic acid; levulinic acid; maleic acid; 2,5-furandicarboxylic acid; mandelic acid; malic acid; and tartaric acid.