PROCESS OF RECOVERING ALKALI METAL SALT HYDRATE AND 3-HYDROXYPROPIONIC ACID

Abstract

The present invention relates to a process of recovering alkali metal salt hydrate and 3-hydroxypropionic acid, comprising: forming and separating 3-hydroxypropionic acid salt crystal from a concentrate containing 3-hydroxypropionic acid in the presence of an alkali metal salt; and adding an acid to the aqueous solution containing the separated 3-hydroxypropionic acid salt crystal to form and separate an alkali metal salt hydrate and 3-hydroxypropionic acid.

Claims

1. A process of recovering an alkali metal salt hydrate and 3-hydroxypropionic acid, comprising: forming and separating a 3-hydroxypropionic acid salt crystal from a concentrate containing 3-hydroxypropionic acid in the presence of an alkali metal salt; forming an aqueous solution containing the 3-hydroxypropionic acid salt crystal; and adding an acid to the aqueous solution containing the 3-hydroxypropionic acid salt crystal to form and separate the alkali metal salt hydrate and the 3-hydroxypropionic acid.

2. The process of recovering an alkali metal salt hydrate and 3-hydroxypropionic acid according to claim 1, wherein: the aqueous solution contains at least 100 g/L of the 3-hydroxypropionic acid salt crystal.

3. The process of recovering an alkali metal salt hydrate and 3-hydroxypropionic acid according to claim 1, wherein: the adding an acid to the aqueous solution containing the 3-hydroxypropionic acid salt crystal to form and separate the alkali metal salt hydrate and the 3-hydroxypropionic acid comprises, separating the alkali metal salt hydrate from the acid-added solution containing the alkali metal salt hydrate and the 3-hydroxypropionic acid; and electrodialyzing the acid-added solution from which the alkali metal salt hydrate has been separated.

4. The process of recovering an alkali metal salt hydrate and 3-hydroxypropionic acid according to claim 3, wherein: the electrodialyzing is carried out until the time point when electrical conductivity in a desalination tank for recovering a desalting product formed by the electrodialyzing is reduced to 50% or less of an initial electrical conductivity in the desalination tank.

5. The process of recovering an alkali metal salt hydrate and 3-hydroxypropionic acid according to claim 1, further comprising: reacting the alkali metal salt hydrate with ammonia water to form an alkali metal hydroxide.

6. The process of recovering an alkali metal salt hydrate and 3-hydroxypropionic acid according to claim 1, further comprising: adding the alkali metal salt hydrate to a hydroxide ion (OH.sup.?)-containing solution to form an alkali metal hydroxide.

7. The process of recovering an alkali metal salt hydrate and 3-hydroxypropionic acid according to claim 5, wherein: the alkali metal hydroxide is reused as the alkali metal salt in the forming and separating a 3-hydroxypropionic acid salt crystal from the concentrate containing 3-hydroxypropionic acid.

8. The process of recovering alkali metal salt hydrate and 3-hydroxypropionic acid according to claim 5, further comprising: fermenting a bacterium strain having 3-hydroxypropionic acid-producing ability to produce a 3-hydroxypropionic acid fermentation liquid; and concentrating the 3-hydroxypropionic acid fermentation liquid to form the concentrate containing 3-hydroxypropionic acid, wherein the alkali metal hydroxide is reused during the fermentation to carry out neutral fermentation.

9. The process of recovering an alkali metal salt hydrate and 3-hydroxypropionic acid according to claim 1, further comprising: reacting the alkali metal salt hydrate with a carbonate to form an alkali metal carbonate.

10. The process of recovering an alkali metal salt hydrate and 3-hydroxypropionic acid according to claim 1, wherein: the acid is phosphoric acid, and the alkali metal salt hydrate is phosphoric acid salt.

11. The process of recovering an alkali metal salt hydrate and 3-hydroxypropionic acid according to claim 1, wherein: the adding an acid to the aqueous solution containing the 3-hydroxypropionic acid salt crystal to form and separate the alkali metal salt hydrate and 3-hydroxypropionic acid comprises, contacting a solution containing 3-hydroxypropionic acid formed after separating the alkali metal salt hydrate with a cation exchange resin column; and recovering the 3-hydroxypropionic acid from the solution contacted with the cation exchange resin column.

12. The process of recovering an alkali metal salt hydrate and 3-hydroxypropionic acid according to claim 1, wherein: the acid is added to the aqueous solution containing the 3-hydroxypropionic acid salt crystal at a temperature of the aqueous solution of 0? C. or more and 90? C. or less.

13. The process of recovering an alkali metal salt hydrate and 3-hydroxypropionic acid according to claim 1, wherein: a precipitate having a particle size of 0.5 ?m or more and 500.0 ?m or less is formed during the adding of the acid to the aqueous solution containing the 3-hydroxypropionic acid salt crystal.

14. The process of recovering an alkali metal salt hydrate and 3-hydroxypropionic acid according to claim 13, wherein: a moisture content of the precipitate is 200% or less.

15. The process of recovering an alkali metal salt hydrate and 3-hydroxypropionic acid according to claim 1, wherein: the concentrate contains at least 300 g/L of the 3-hydroxypropionic acid.

16. The process of recovering an alkali metal salt hydrate and 3-hydroxypropionic acid according to claim 1, wherein: the concentrate contains 350 g/L or more and 900 g/L or less of the 3-hydroxypropionic acid.

17. The process of recovering an alkali metal salt hydrate and 3-hydroxypropionic acid according to claim 1, wherein: the aqueous solution contains the 3-hydroxypropionic acid salt crystal at a concentration of 100 g/L or more and 800 g/L or less.

18. The process of recovering an alkali metal salt hydrate and 3-hydroxypropionic acid according to claim 1, wherein: the alkali metal salt is Ca(OH).sub.2, Mg(OH).sub.2 or a mixture thereof.

19. The process of recovering an alkali metal salt hydrate and 3-hydroxypropionic acid according to claim 1, wherein: the 3-hydroxypropionic acid salt crystal includes 3-hydroxypropionic acid calcium salt.

20. The process of recovering an alkali metal salt hydrate and 3-hydroxypropionic acid according to claim 1, wherein: the 3-hydroxypropionic acid salt crystal has a particle size distribution D.sub.50 of 20 ?m or more and 300 ?m or less, and a (D.sub.90?D.sub.10)/D.sub.50 of 1.00 or more and 3.00 or less, and the 3-hydroxypropionic acid salt crystal has a radioactive carbon isotope content of at least 20 pMC (percent modem carbon), and a biocarbon content of at least 20 wt. %, as measured according to the standard of ASTM D6866-21.

21. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0191] FIG. 1 shows the results of X-ray diffraction analysis of the precipitate formed in Example 1.

[0192] FIG. 2 shows the results of X-ray diffraction analysis of the precipitate formed in Example 2.

[0193] FIG. 3 is a graph showing the amount of change in electrical conductivity over time in the electrodialysis step of Example 4.

[0194] FIG. 4 shows the results of X-ray diffraction analysis of solid A of Example 6.

[0195] FIG. 5 shows the results of standard X-ray diffraction analysis of calcium hydroxide.

[0196] FIG. 6 shows the results of X-ray diffraction analysis of solid A of Example 7.

[0197] FIG. 7 shows the results of X-ray diffraction analysis of solid B of Example 7.

[0198] FIG. 8 shows the results of X-ray diffraction analysis of solid A of Example 8.

[0199] FIG. 9 shows the results of standard X-ray diffraction analysis of calcium carbonate.

[0200] FIG. 10 shows the results of X-ray diffraction analysis of solid B of Example 8.

[0201] FIG. 11 is a graph overlapping X-ray diffraction analysis results of solid A, calcium carbonate and solid B of Example 8.

[0202] Hereinafter, the present invention will be described in more detail with reference to examples. However, the following examples are for illustrative purposes only, and are not intended to limit the scope of the present invention.

Preparation Example 1: Preparation of Bacterium Strain for Producing 3-Hydroxypropionic Acid

[0203] Recombinant vectors into which genes encoding glycerol dehydratase and aldehyde dehydrogenase, which are known to produce 3-hydroxypropionic acid (3HP) using glycerol as a substrate, were introduced were manufactured. The prepared recombinant vector was introduced into E. coli W3110 strain to prepare a 3-hydroxypropionic acid-producing strain.

[0204] More specifically, a BtuR gene encoding adenosyltransferase was cloned into plasmid pCDF containing a gene (dhaB) encoding glycerol dehydratase, a gene (aldH) encoding aldehyde dehydrogenase and a gene (gdrAB) encoding glycerol dehydratase reactivase. The resulting pCDF_J23101_dhaB_gdrAB_J23100_aldH_btuR vector was introduced into strain W3110 (KCCM 40219) by an electroporation method using an electroporation device (Bio-Rad, Gene Pulser Xcell) to prepare 3-hydroxypropionic acid-producing strain. The process of preparing the 3-hydroxypropionic acid-producing strain of Preparation Example 1 and the vectors, primers, and enzymes used were carried out with reference to Example 1 of Korean Unexamined Patent Publication No. 10-2020-0051375, which is incorporated herein by reference.

Preparation Example 2: Preparation of Ca(3HP).SUB.2 .Crystal

[0205] The 3-hydroxypropionic acid-producing strain prepared in Preparation Example 1 was fermented and cultured at 35? C. in a 5 L fermenter using unpurified glycerol as a carbon source to produce 3-hydroxypropionic acid. In order to prevent the lowering of pH due to the production of 3-hydroxypropionic acid, calcium hydroxide (Ca(OH).sub.2), which is an alkali metal salt, was added to keep the neutral pH during the fermentation.

[0206] After fermented culture, cells were removed by centrifugation (4000 rpm, 10 minutes, 4? C.), and primary fermentation liquid purification (primary purification) was performed using activated carbon. Specifically, activated carbon was added to the fermentation liquid from which cells were removed by centrifugation, the mixture was well mixed, and then centrifuged again to separate the activated carbon. Then, the fermentation liquid from which the activated carbon was separated was filtered with a vacuum pump through a 0.7 um filter paper to purify the 3-hydroxypropionic acid fermented liquid.

[0207] The concentration of 3-hydroxypropionic acid in the fermentation liquid after the primary purification was at a level of 50 to 100 g/L, and the fermentation liquid was concentrated to a concentration of 600 g/L using a rotary evaporator (50? C., 50 mbar) to prepare a concentrate, and ethanol was added in an amount of two times the volume of the concentrate, and stirred (300 rpm) at room temperature to produce Ca(3HP).sub.2 crystals. At this time, the concentration of the alkali metal salt in the concentrate was 493.3 g/L (based on Ca(OH).sub.2). The resulting crystals were washed three times with ethanol (EtOH) and dried in an oven at 50? C. to finally recover the crystals.

Example 1

[0208] An aqueous solution containing 600 g/L of Ca(3HP).sub.2 crystal recovered in Preparation Example 2 was prepared, and stirred at a temperature of 25? C. and 350 rpm for 10 minutes. 37 ml of 5M sulfuric acid solution was added to 77 ml of the aqueous solution at a uniform rate for 5 minutes, and further stirred for 30 minutes to form a slurry containing CaSO.sub.4 precipitate and 3-hydroxypropionic acid.

[0209] Filtration was performed using a filtration flask and a vacuum pump in order to separate the CaSO.sub.4 precipitate. Then, a filtrate (A) before washing was obtained in a filtering flask, and the filtered CaSO.sub.4 precipitate was washed with 30 ml of distilled water, and then filtered to obtain a filtrate (B) after washing. Then, the CaSO.sub.4 precipitate was dried in an oven at a temperature of 60? C. for 20 hours to finally obtain the dried CaSO.sub.4 precipitate. In addition, filtrates (A) and (B) containing 3-hydroxypropionic acid were obtained.

Example 2

[0210] An aqueous solution containing 150 g/L of Ca(3HP).sub.2 crystal recovered in Preparation Example 2 was prepared, and heated to a temperature of 60? C. while stirring at 350 rpm.

[0211] 250 ml of 2.72M sulfuric acid solution was added to 1 L of the aqueous solution at a uniform rate for 60 minutes, and further stirred for 30 minutes to form a slurry containing CaSO.sub.4 precipitate and 3-hydroxypropionic acid, which was further stirred until the temperature dropped to room temperature.

[0212] Filtration was performed using a filtration flask and a vacuum pump in order to separate the CaSO.sub.4 precipitate. Then, a filtrate (A) before washing was obtained in a filtering flask, and the filtered CaSO.sub.4 precipitate was washed with 100 ml of distilled water, and then filtered to obtain a filtrate (B) after washing. Then, the CaSO.sub.4 precipitate was dried in an oven at a temperature of 60? C. for 20 hours to finally obtain the dried CaSO.sub.4 precipitate. In addition, filtrates (A) and (B) containing 3-hydroxypropionic acid were obtained.

Example 3

[0213] A cation exchange resin column was filled with 12 BV of cation exchange resin, and then washed with water to prepare a cation exchange resin column. At this time, TRILITE?CMP28LH (Samyang Corporation) was used as a cation exchange resin.

[0214] The entire filtrate containing 3-hydroxypropionic acid obtained in Example 2 was charged into a cation exchange resin column at a space velocity (SV) of 2.4, and then distilled water was charged into to the cation exchange resin column at a space velocity (SV) of 7.2 or less to obtain a 3-hydroxypropionic acid aqueous solution with a pH of 2.5 or less.

Example 4

[0215] An aqueous solution containing 300 g/L of Ca(3HP).sub.2 crystal recovered in Preparation Example 2 was prepared, and stirred at a temperature of 60? C. and 350 rpm for 10 minutes.

[0216] 5M sulfuric acid solution was added to the aqueous solution at a uniform rate for 5 minutes so that the equivalents of 3-hydroxypropionic acid and sulfuric acid were 1:1, and further stirred for 30 minutes to form a slurry containing CaSO.sub.4 precipitate and 3-hydroxypropionic acid.

[0217] Filtration was performed using a filtration flask and a vacuum pump in order to separate the CaSO.sub.4 precipitate. Then, after obtaining the filtrate (A) before washing in the filtration flask, the filtered CaSO.sub.4 precipitate was washed with 30 ml of distilled water and then filtered to obtain a filtrate (B) after washing. Then, the CaSO.sub.4 precipitate was dried in an oven at 40? C. for 20 hours to finally obtain the dried CaSO.sub.4 precipitate.

[0218] The obtained filtrate (B) was electrodialyzed using an electrodialysis device (Innomeditech Inc.) Specifically, an electrodialysis tank of the electrodialysis device used L3 membrane (Innomeditech Inc.) as a cation and anion separation membrane, and progressed with a 20-cell constant voltage method (20V, 1V per cell) for 40 minutes. At this time, the desalination tank progressed electrodialysis until the electrical conductivity was lowered to 10% compared to the initial conductivity 100% of the desalination tank, to thereby recover 3-hydroxypropionic acid.

Example 5

[0219] An aqueous solution containing 300 g/L of Ca(3HP).sub.2 crystal recovered in Preparation Example 2 was prepared, and heated to a temperature of 60? C. while stirring at 350 rpm.

[0220] 5M sulfuric acid solution was added to the aqueous solution at a uniform rate for 5 minutes so that the equivalents of 3-hydroxypropionic acid and sulfuric acid were 1:1.2, and further stirred for 30 minutes to form a slurry containing CaSO.sub.4 precipitate and 3-hydroxypropionic acid.

[0221] Filtration was performed using a filtration flask and a vacuum pump in order to separate the CaSO.sub.4 precipitate. Then, a filtrate (A) before washing was obtained in a filtering flask, and then the filtered CaSO.sub.4 precipitate was washed with 30 ml of distilled water, and then filtered to obtain a filtrate (B) after washing. Then, the CaSO.sub.4 precipitate was dried in an oven at a temperature of 40? C. for 20 hours to finally obtain the dried CaSO.sub.4 precipitate.

[0222] The obtained filtrate (B) was electrodialyzed using an electrodialysis device (Innomeditech Inc.) Specifically, an electrodialysis tank of the electrodialysis device used L3 membrane (Innomeditech Inc.) as a cation and anion separation membrane, and progressed with a 20-cell constant voltage method (20V, 1V per cell) for 40 minutes. At this time, as shown in FIG. 1, the desalination tank progressed electrodialysis until the time point when the electrical conductivity was lowered to 10% compared to the initial conductivity 100% of the desalination tank, to thereby recover 3-hydroxypropionic acid.

Example 6

[0223] An aqueous solution containing 600 g/L of Ca(3HP).sub.2 crystal recovered in Preparation Example 2 was prepared, and stirred at a temperature of 25? C. and 350 rpm for 10 minutes.

[0224] 37 ml of 5M sulfuric acid solution was added to 77 mL of the aqueous solution at a uniform rate for 30 minutes, and further stirred for 30 minutes to form a slurry containing CaSO.sub.4 precipitate and 3-hydroxypropionic acid. Filtration was performed using a filtration flask and a vacuum pump in order to separate the CaSO.sub.4 precipitate.

[0225] The separated CaSO.sub.4 precipitate was dried in an oven at a temperature of 80? C. for 20 hours to recover gypsum anhydrite(CaSO.sub.4), which is a solid A. 2.72 g of gypsum anhydrite (CaSO.sub.4) was added to 400 mL of 1 M ammonia water solution (20 equivalents relative to gypsum anhydrite), and then the mixture was stirred at 200 rpm using a magnetic steel bar while maintaining the temperature at 30? C. After a reaction time of 4 hours has elapsed, the precipitate was filtered using a filtration flask and a vacuum pump to obtain a solid B containing a small amount of moisture. Then, the solid B was dried to recover the dried solid B.

Example 7

[0226] An aqueous solution containing 600 g/L of Ca(3HP).sub.2 crystal recovered in Preparation Example 2 was prepared, and stirred at a temperature of 25? C. and 350 rpm for 10 minutes.

[0227] 37 ml of 5M sulfuric acid solution was added to 77 mL of the aqueous solution at a uniform rate for 5 minutes, and further stirred for 30 minutes to form a slurry containing CaSO.sub.4 precipitate and 3-hydroxypropionic acid. Filtration was performed using a filtration flask and a vacuum pump in order to separate the CaSO.sub.4 precipitate.

[0228] The separated CaSO.sub.4 precipitate was dried in an oven at a temperature of 80? C. for 20 hours to recover gypsum anhydrite (CaSO.sub.4), which is a solid A. 5.44 g of gypsum anhydrite (CaSO.sub.4) was added to 200 mL of 1 M sodium hydroxide (NaOH) aqueous solution (5 equivalents relative to gypsum anhydrite), and then the mixture was stirred at 200 rpm using a magnetic steel bar while maintaining the temperature at 30? C. After a reaction time of 4 hours has elapsed, the precipitate was filtered using a filtration flask and a vacuum pump to obtain a solid B containing a small amount of moisture. Then, the solid B was dried to recover 2.38 g of the dried solid B.

Example 8

[0229] An aqueous solution containing 600 g/L of Ca(3HP).sub.2 crystal recovered in Preparation Example 2 was prepared, and stirred at a temperature of 25? C. and 350 rpm for 10 minutes.

[0230] 37 ml of 5M sulfuric acid solution was added to 77 mL of the aqueous solution at a uniform rate for 5 minutes, and further stirred for 30 minutes to form a slurry containing CaSO.sub.4 precipitate and 3-hydroxypropionic acid. Filtration was performed using a filtration flask and a vacuum pump in order to separate the CaSO.sub.4 precipitate.

[0231] The separated CaSO.sub.4 precipitate was dried in an oven at a temperature of 80? C. for 20 hours to recover gypsum anhydrite (CaSO.sub.4), which is a solid A. 4.08 g of gypsum anhydrite (CaSO.sub.4) was added to 750 mL of 0.2 M ammonium carbonate ((NH.sub.4).sub.2CO.sub.3) aqueous solution (5 equivalents relative to gypsum anhydrite), and then the mixture was stirred at 200 rpm using a magnetic steel bar while maintaining the temperature at 30? C. After a reaction time of 4 hours has elapsed, the precipitate was filtered using a filtration flask and a vacuum pump to obtain a solid B containing a small amount of moisture. Then, the solid B was dried to recover 2.67 g of the dried solid B.

Example 9

[0232] An aqueous solution containing 250 g/L of Ca(3HP).sub.2 crystal recovered in Preparation Example 2 was prepared, and stirred at a temperature of 60? C. and 200 rpm for 10 minutes.

[0233] 5M phosphoric acid solution was added to the aqueous solution at a uniform rate for 30 minutes so that the equivalents of 3-hydroxypropionic acid and phosphoric acid were 1:1, and further stirred for 30 minutes to form a slurry containing calcium phosphate salt precipitate and 3-hydroxypropionic acid.

[0234] Filtration was performed using a filtration flask and a vacuum pump in order to separate the calcium phosphate salt precipitate. Then, a filtrate(A) before washing was obtained in a filtering flask, and the filtered calcium phosphate salt precipitate was washed with 30 ml of distilled water, and then filtered to obtain a filtrate(B) after washing. Then, the calcium phosphate salt precipitate was dried in an oven at a temperature of 80? C. for 20 hours to finally obtain the dried calcium phosphate salt precipitate.

[0235] A cation exchange resin tower (JCL-GF-F110, JUNG Glass Pyrex) was filled with 12 BV of cation exchange resin, and then washed with water to prepare a cation exchange resin column. At this time, TRILITE?CMP28LH (Samyang Corporation) was used as a cation exchange resin.

[0236] The entire filtrate (B) obtained above was charged into a cation exchange resin column at a space velocity (SV) of 2.4 m.sup.3 h?1, and then distilled water was charged into the cation exchange resin column at a space velocity (SV) of 7.2 m.sup.3 h.sup.?1 or less to obtain a 3-hydroxypropionic acid aqueous solution with a pH of 2.5 or less.

Example 10

[0237] An aqueous solution containing 250 g/L of Ca(3HP).sub.2 crystal recovered in Preparation Example 2 was prepared, and stirred at a temperature of 25? C. and 200 rpm for 10 minutes.

[0238] 5M phosphoric acid solution was added to the aqueous solution at a uniform rate for 5 minutes so that the equivalents of 3-hydroxypropionic acid and phosphoric acid were 1:1, and further stirred for 30 minutes to form a slurry containing calcium phosphate salt precipitate and 3-hydroxypropionic acid.

[0239] Filtration was performed using a filtration flask and a vacuum pump in order to separate the calcium phosphate salt precipitate. Then, a filtrate(A) before washing was obtained in a filtering flask, and then the filtered calcium phosphate salt precipitate was washed with 30 ml of distilled water, and then filtered to obtain a filtrate(B) after washing. Then, the calcium phosphate salt precipitate was dried in an oven at a temperature of 80? C. for 20 hours to finally obtain the dried calcium phosphate salt precipitate.

[0240] A cation exchange resin tower (JCL-GF-F110, JUNG Glass Pyrex) was filled with 12 BV of cation exchange resin, and then washed with water to prepare a cation exchange resin column. At this time, TRILITE?CMP28LH (Samyang Corporation) was used as a cation exchange resin.

[0241] The entire filtrate (B) obtained above was charged into a cation exchange resin column at a space velocity (SV) of 2.4 m.sup.3 h?1, and then distilled water was charged into the cation exchange resin column at a space velocity (SV) of 7.2 m.sup.3 h?1 or less to obtain an aqueous 3-hydroxypropionic acid solution with a pH of 2.5 or less.

Comparative Example 1

[0242] 5M sulfuric acid solution was added to the 3-hydroxypropionic acid fermentation liquid (concentration of about 100 g/L), which had undergone primary purification in Preparation Example 2, at a uniform rate for 5 minutes, so that the equivalents of 3-hydroxypropionic acid and sulfuric acid were 1:1, and further stirred for 30 minutes to form a slurry containing CaSO.sub.4 precipitate and 3-hydroxypropionic acid.

[0243] Filtration was performed using a filtration flask and a vacuum pump in order to separate the CaSO.sub.4 precipitate. Then, a filtrate(A) before washing was obtained in a filtering flask, and then the filtered CaSO.sub.4 precipitate was washed with 30 ml of distilled water, and then filtered to obtain a filtrate(B) after washing, which was concentrated (about 30 wt. %). The concentrated filtrate was passed through a cation exchange resin (TRILITE?CMP28LH, Samyang Corporation) to remove residual ionic impurities, thereby recovering a 3-hydroxypropionic acid-containing solution having a concentration of 300 g/L.

[0244] Then, the CaSO.sub.4 precipitate was dried in an oven at a temperature of 40? C. for 20 hours to finally obtain the dried CaSO.sub.4 precipitate.

Test Example

1. Evaluation of Removal Rate of Calcium (Ca) Element

[0245] When converting the 3-hydroxypropionic acid salt crystal (Ca(3HP).sub.2 crystal) in Examples 1 to 5, 9, and 10 and Comparative Example 1 to 3-hydroxypropionic acid, CaSO.sub.4 precipitates (or calcium phosphate salt precipitates) were produced, and thus, the content of the calcium (Ca) element removed was measured by an ion chromatography analysis.

[0246] Specifically, the content (X.sub.ref) of calcium (Ca) element contained in the 32.0 wt. % Ca (3HP).sub.2 aqueous solution, and the content (X.sub.filtration) of calcium (Ca) element contained in the filtrate (B) after washing were respectively analyzed, and the removal rate of the calcium (Ca) element was calculated according to the following general formula 1, and the results are shown in Table 1 below.

[00001]$\begin{array}{cc}\mathrm{Removal}\mathrm{rate}\mathrm{of}\mathrm{calcium}\left(\mathrm{Ca}\right)\mathrm{element}\left(\%\right)=\left(X_{\mathrm{ref}}-X_{\mathrm{filtration}}\right)/X_{\mathrm{ref}}*100& \left[\mathrm{General}\mathrm{Formula}1\right]\end{array}$

2. Measurement of Recovery Rate of 3-Hydroxypropionic Acid

[0247] The recovery rate of 3-hydroxypropionic acid obtained in Examples 1 to 5, 9, and 10 and Comparative Example 1 was measured and calculated using a high-performance liquid chromatography (HPLC).

[0248] Specifically, the absolute amount(X) of 3-hydroxypropionic acid in the aqueous solution containing Ca(3HP).sub.2 crystal and the absolute amount(Y) of 3-hydroxypropionic acid in the filtrate were measured, and the recovery rate of 3-hydroxypropionic acid was calculated according to the following general formula 2.

[00002]$\begin{array}{cc}\mathrm{Recovery}\mathrm{rate}\mathrm{of}3-\mathrm{hydroxypropionic}\mathrm{acid}\left(\%\right)=\left(Y/X\right)*100& \left[\mathrm{General}\mathrm{Formula}2\right]\end{array}$

3. Measurement of Impurity Content Impurities contained in the solutions finally recovered in Examples 1 to 5, 9, 10 and Comparative Example 1 were measured by a nuclear magnetic resonance spectroscopy (NMR) and a high performance liquid chromatography (HPLC). On the other hand, if the impurity content was not measured, it was marked as ?.

(1) High-Performance Liquid Chromatography (HPLC)

[0249] The ratio of impurities (glycerol, acetate and 1,3-propanediol) and 3-hydroxypropionic acid (3HP) was measured using HPLC.

[0250] For HPLC, 0.5 mM sulfuric acid (H.sub.2SO.sub.4) was flowed at a flow rate of 0.4 mL/min using an Aminex HPX-87H ion exclusion column (7.8*300 mm, 9 ?m), the temperature of the column was 35? C., the injection volume was 5 ?L, and the UV detector was set to 210 nm.

(2).SUP.1.H-Nmr

[0251] The content ratio of impurities (glycerol, acetate, and 1,3-propanediol) and 3-hydroxypropionic acid (3HP) was analyzed using .sup.1H-NMR.

[0252] 100 ?L of unpurified alkali metal 3-hydroxypropionic acid salt and purified 3-hydroxypropionic acid were sampled, and dissolved in 500 ?L of D2O which is NMR solvent, and a solution added with 11.5 ?L of dimethylformamide (DMF) where moisture was removed was transferred to an NMR tube to prepare a sample for .sup.1H-NMR measurement.

[0253] .sup.1H-NMR spectrum (AVANCE Ill HD FT-NMR spectrometer (500 MHz for 1 H), manufactured by Bruker) was measured using the sample for measurement.

TABLE-US-00001 TABLE 1 Removal Recovery rate of rate of 3- calcium(Ca) hydroxypropionic Impurity content (ppm) element (%) acid (%) Glycerol Acetate 1,3-propanol Example 1 99.0 69.68 Example 2 98.0 99.50 Example 3 99.0 99.10 Example 4 99.0 99.80 Detection Detection Detection limit limit limit Example 5 99.9 95.20 Detection Detection Detection limit limit limit Example 9 90.0 92.00 Detection 110 Detection limit limit Example 10 90.0 91.00 Detection 120 Detection limit limit Comparative 95.0 90.00 2451 455 120 Example 1

[0254] Referring to Table 1, it was confirmed that in Examples 1 to 5, 9 and 10, 3-hydroxypropionic acid was recovered by about 69.68% or more, while calcium element was removed by 90% or more. It was also confirmed that in Examples 4 and 5 in which 3-hydroxypropionic acid was purified through electrodialysis, no impurities were detected.

[0255] Thereby, it could be confirmed that according to the recovery process of 3-hydroxypropionic acid of Examples, the cation can be effectively separated from 3-hydroxypropionic acid salt to efficiently produce high-purity 3-hydroxypropionic acid.

4. Analysis of Precipitate Components

[0256] Conversion of 3-hydroxypropionic acid salt crystal (Ca(3HP).sub.2 crystals) to 3-hydroxypropionic acid appears to form a precipitate containing CaSO.sub.4, and specific component analysis for such precipitates was performed using an X-ray fluorescence spectrometer (XRF).

[0257] Specifically, primary element chemical analysis was performed on a ThermoARL Advant'X Sequential XRF with Uniquant standardless software and loss on ignition (LOI) normalization (moisture content included in the normalization), the loss on ignition (LOI) value was measured in an electric furnace maintained at 975? C., and the crystal moisture was determined by the LOI difference in a drying oven at 250? C.

TABLE-US-00002 TABLE 2 Component (wt. %) Crystal SiO.sub.2 Al.sub.2O.sub.3 Fe.sub.2O.sub.3 CaO MgO SO.sub.3 LOI moisture Example 1 0.53 0.68 0.42 31.19 52.83 13.44 12.38 Example 2 0.50 0.35 30.12 49.13 18.77 17.8

[0258] Then, the type and crystal form of the material were measured for the obtained precipitate using an X-ray diffraction analyzer (Bruker AXS D4-Endeavor XRD). Specifically, measurement was performed under the following conditions; the applied voltage was 40 kV, the applied current was 40 mA, the range of 2theta measured was 10? to 90?, and it was scanned at intervals of 0.05?.

TABLE-US-00003 TABLE 3 wt. % Gypsums Gypsum Gypsum Gypsum Minerals dihydrate hemihydrate anhydrite subtotal calcite dolomite illite Ichlorite microcline subtotal Example 1 1.56 42.57 51.69 95.82 0.16 0.78 0.41 0.27 2.56 4.18 Example 2 72.04 23.65 2.12 97.81 0.22 1.04 0.83 2.09

[0259] Referring to Tables 2 and 3, it was confirmed that the precipitate obtained in Examples contains 95.82% or more of gypsum dihydrate, gypsum hemihydrate and gypsum anhydrite based on the total content, contains almost no minerals such as calcite and dolomite, and also contains almost no impurities such as SiO.sub.2.

5. Analysis of the Crystal Phase of the Precipitate

[0260] It was confirmed that in Examples 6 to 8, the type and crystal form of the materials were measured for solids A and B using an X-ray diffraction analyzer (Bruker AXS D4-Endeavor XRD). Specifically, measurement was performed under the following conditions; the applied voltage was 40 kV, the applied current was 40 mA, and Cu-K? radiation (wavelength ?=1.54184 ?) was irradiated, and the range of 2theta measured was 10? to 90?, and it was scanned at intervals of 0.05?.

[0261] The diffraction angle (2??0.2?) at which the main peak appears in the results of XRD analysis of the solids A and B of Example 6, and the diffraction angle (2??0.2?) at which the main peak appears in the results of standard XRD analysis of calcium hydroxide (Ca(OH).sub.2) are shown in Table 4 below.

[0262] The diffraction angle (2??0.2?) at which the main peak appears in the results of XRD analysis of solids A and B of Example 7, and the diffraction angle (2??0.2?) at which the main peak appears in the results of standard XRD analysis of calcium hydroxide (Ca(OH).sub.2) are shown in Table 5 below.

[0263] The diffraction angle (2??0.2?) at which the main peak appears in the results of XRD analysis of solids A and B of Example 8, and the diffraction angle (2??0.2?) at which the main peak appears in the results of standard XRD analysis of calcium carbonate are shown in Table 6 below.

[0264] On the other hand, FIG. 4 shows the results of X-ray diffraction analysis of solid A (CaSO.sub.4) of Example 6, and FIG. 5 shows the results of standard X-ray diffraction analysis of calcium hydroxide (Ca(OH).sub.2). Further, FIG. 6 shows the results of X-ray diffraction analysis of solid A (CaSO.sub.4) of Example 7, and FIG. 7 shows the results of X-ray diffraction analysis of solid B of Example 7. Further, FIG. 8 shows the results of X-ray diffraction analysis of solid A (CaSO.sub.4) of Example 8, FIG. 9 shows the results of standard X-ray diffraction analysis of calcium carbonate (CaCO.sub.3), FIG. 10 shows the results of X-ray diffraction analysis of solid B of Example 8, and FIG. 11 is a graph overlapping X-ray diffraction analysis results of solid A(CaSO.sub.4), calcium carbonate and solid B of Example 8.

TABLE-US-00004 TABLE 4 Diffraction angle (2? ? 0.2?) at which the main peak appears Solid A 23, 25.4, 28.6, 31.4, 32, 36.4, 38.8, 40.9, 41.4, 43.4, (CaSO.sub.4) 45.6, 46.9, 48.8, 49.2, 52.4, 55.8, 57.9, 59.2 Standard 18, 28.8, 34, 47.2, 51, 54.4, 56.2, 59.5 calcium hydroxide Solid B 18, 28.8, 34, 47.2, 51, 54.4, 56.2, 59.5

TABLE-US-00005 TABLE 5 Diffraction angle (2? ? 0.2?) at which the main peak appears Solid A 23, 25.4, 28.6, 31.4, 32, 36.4, 38.8, 40.9, 41.4, 43.4, (CaSO.sub.4) 45.6, 46.9, 48.8, 49.2, 52.4, 55.8, 57.9, 59.2 Standard 18, 28.8, 34, 47.2, 51, 54.4, 56.2, 59.5 calcium hydroxide Solid B 18, 28.8, 34, 47.2, 51, 54.4, 56.2, 59.5

[0265] Referring to Tables 4 and 5, it was confirmed that the XRD pattern of the solid B of Examples 6 and 7 was identical the standard XRD pattern of calcium hydroxide, and especially, the XRD pattern of the solid A were not observed in the XRD pattern of the solid B, and thus, the reaction between gypsum anhydrite (CaSO.sub.4) and ammonia water (or sodium hydroxide) was carried out at a conversion rate of 100%, so that no gypsum anhydrite (CaSO.sub.4) remained, and calcium hydroxide was produced.

TABLE-US-00006 TABLE 6 Diffraction angle (2? ? 0.2?) at which the main peak appears Solid A 23, 25.4, 28.6, 31.4, 32, 36.4, 38.8, 40.9, 41.4, 43.4, (CaSO.sub.4) 45.6, 46.9, 48.8, 49.2, 52.4, 55.8, 57.9, 59.2 Standard 23, 29.2, 31.2, 36, 39.4, 43.2, 47.4, 48.5, 57.5 calcium carbonate Solid B 23, 29.2, 31.2, 36, 39.4, 43, 47, 47.4, 48.5, 56.4, 57.2

[0266] Referring to Table 6, it was confirmed that the XRD pattern of the solid B of Example 8 was identical to the standard XRD pattern of calcium carbonate, especially, the XRD pattern of the solid A was not observed in the XRD pattern of the solid B, and the reaction between gypsum anhydrite (CaSO.sub.4) and ammonium carbonate ((NH.sub.4).sub.2CO.sub.3) was carried out at a conversion rate of 100%, so that no gypsum anhydrite (CaSO.sub.4) remained, and calcium carbonate was produced.

2. Recovery Rate of Alkali Metal Hydroxide

[0267] The recovery rates of the alkali metal hydroxides (solid B) of Examples 6 and 7 and the metal carbonates (solid B) of Example 8 were measured by a high performance liquid chromatography (HPLC), and the results are shown in Table 7 below. Specifically, the content (Y) of the alkali metal salt contained in the concentrate and the content (X) of the hydroxide/carbonate (solid B) of the finally recovered alkali metal was measured, which were respectively substituted into the following general formula 3 to calculate the recovery rate of the alkali metal hydroxide.

[00003]$\begin{array}{cc}\mathrm{Recovery}\mathrm{rate}\mathrm{of}\mathrm{alkali}\mathrm{metal}\mathrm{hydroxide}/\mathrm{carbonate}\left(\%\right)=X/Y*100& \left[\mathrm{General}\mathrm{Formula}3\right]\end{array}$

TABLE-US-00007 TABLE 7 Recovery rate of alkali metal hydroxide/carbonate (%) Example 6 85 Example 7 80 Example 8 89

[0268] According to Table 7, it was confirmed that 80% or more of the alkali metal salt used in the process of fermenting 3-hydroxypropionic acid or forming 3-hydroxypropionic acid salt crystal was finally recovered in the form of alkali metal hydroxide (or alkali metal carbonate).