JPH03183487A - Separation and recovery of organic acid - Google Patents

Abstract

PURPOSE:To profitably and effectively perform the recovery of the subject useful organic acid by simple operation processes by treating an organic acid- containing aqueous solution with a cation exchange resin and subsequently with an anion exchange resin. CONSTITUTION:An organic acid-containing aqueous solution containing amino acids and/or soluble proteins and an organic acid is subjected to a contact with a cation exchange resin and subsequently to a contact with an anion exchange resin to allow the anion exchange resin to absorb the organic acid. The adsorbed organic acid is eluted with an eluting agent for the recovery of the organic acid from the elution solution. The organic acid-containing aqueous solution is preferably the sulfurous acid immersion solution of corn.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for separating and recovering organic acids. More specifically, organic acids are removed from an aqueous solution containing amino acids and/or soluble proteins, and organic acids and optionally inorganic components by treating the solution with a cation exchange resin and then with an anion exchange resin. Concerning separation and recovery methods.

<Conventional technology> Organic acids that exist in nature, such as lactic acid, tartaric acid, citric acid, and malic acid, have been used for food and drink since ancient times, but today they are used in foods such as beverages, bread, noodles, and pickled vegetables. It is widely used in non-food fields such as paint, leather, plating, detergent builders, and cosmetics.

Conventionally, such organic acids have been obtained by separating and recovering organic acids from an organic acid-containing aqueous solution (fermentation method) obtained by fermenting a sugar solution or the like. Separation and recovery of organic acids produced by fermentation methods is carried out through process treatments such as precipitating and separating the organic acids as calcium salts, and then purifying the calcium salts as free organic acids.

<Problem to be solved by the invention> However, in the conventional production method, the process of separating and recovering organic acids is very complicated, and recovery takes time, and requires a large amount of energy and processing equipment, which reduces operating costs and construction costs. It has disadvantages such as being bulky.

Organic acids are produced as by-products during the manufacturing process of starch and the like, as well as during fermentation and the like. However, although the organic acid-containing aqueous solution (hereinafter referred to as starch manufacturing process liquid) generated in the manufacturing process of starch, etc. contains by-produced organic acids, it also contains a large amount of impurities, and also contains a large amount of impurities. Component concentrations are often low. Therefore, economical recovery of organic acids from starch production process liquids is not possible;
The organic acids produced as by-products are disposed of without being recovered. For example, the sulfite soaking solution of corn obtained in the process of producing corn starch usually contains 5 to 30% amino acids, 5 to 30% sugar, 3 to 15% inorganic salts, and 5 to 30% by weight of inorganic salts.
It contains 5-25% by weight of lactic acid as well as 5-25% by weight of protein. However, since it contains many impurities other than lactic acid, lactic acid cannot be economically recovered, and it is concentrated and consumed as cornstarch liquor, mainly as feed for livestock.

In view of these circumstances, the present inventors have conducted intensive studies to find a method for selectively and efficiently separating and recovering organic acids from organic acid-containing aqueous solutions containing amino acids, soluble proteins, inorganic components, etc. The present inventors have discovered that organic acids can be efficiently adsorbed to an anion exchange resin by first treating them with a cation exchange resin and then contacting the treated aqueous solution with an anion exchange resin, thereby completing the present invention.

Means for Solving the Problems> That is, the present invention provides amino acids and/or soluble proteins,
An organic acid-containing aqueous solution containing an organic acid and an organic acid is contacted with a cation exchange resin, and then the aqueous solution treated with the cation exchange resin is brought into contact with an anion exchange resin to convert the organic acid into an anion. After adsorbing to the exchange resin,
An amino acid and/or soluble protein containing an organic acid and an organic acid characterized in that the anion exchange resin adsorbed with an organic acid is brought into contact with an eluent to elute the organic acid and the organic acid is recovered from the eluent. This is a method for separating and recovering organic acids from organic acid-containing aqueous solutions.

The organic acid of the present invention is one that can form a salt with an ion exchange resin having an amino group.

Examples of such organic acids include (1) lactic acid, tartaric acid, citric acid, malic acid, oxalic acid,
Succinic acid, glutaric acid, adipic acid, pimelic acid, speric acid, azelaic acid, sebacic acid, citraconic acid, mesaconic acid, maleic acid, fumaric acid, phthalic acid, terephthalic acid, trioxyglutaric acid, oxoglutaric acid, 1,
Aliphatic, aromatic or heterocyclic polycarboxylic acids such as 2-naphthalene dicarboxylic acid and 1,8-naphthalene dicarboxylic acid; (2) polyaminopolycarboxylic acids such as ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid and triethylenetetraminehexaacetic acid; , (3) polysulfonic acids such as 4.4'-carbonyldiiminobisbenzenesulfonic acid and 2.2'-carbonyldiiminobisbenzenesulfonic acid, (4) 2'-adenylic acid, 3'-adenylic acid, 5 '-Adenylic acid, 2'-inosinic acid, 3'-inosinic acid, 5'-inosinic acid, 2'-guanylic acid, 3'-guanylic acid, 5'-guanylic acid, 2'
-xanthylic acid, 3'-xanthylic acid, 5'-xantylic acid, 2'-cytidylic acid, 3'-cytidylic acid, 5'-cytidylic acid, 2'-uridylic acid, 3'-uridylic acid, 5'
-uridylic acid, 2'-thymidylic acid, 3'-thymidylic acid,
5'-thymidylic acid, inosine-triphosphate, ynone-diphosphate, adenosine-triphosphate, adenosine-diphosphate, adenosine-5'-tetraphosphate, guanosine-triphosphate, guanosine-diphosphate, guanosine-2'3'- Nucleotides, ribonucleotides and derivatives thereof, such as phosphoric acid, uridyl-triphosphate, uridyl-diphosphate, thymidino-triphosphate, thymidino-diphosphoric acid and their Na, B a SK1 ammonium salts, (5) 2-phosphoglyceric acid, Glyceric acid phosphoric acid such as 3-phosphoglyceric acid, 1.3-diphosphoglyceric acid, 2.3-diphosphoglyceric acid, dioxyacetone phosphoric acid, glycerophosphoric acid, glyceraldehyde-3-phosphoric acid, dioxyacetone-1- Acid esters of glycerin such as phosphoric acid, glycetylphosphocholine, etc. and their Na5B
a, ammonium salt, (6) sugar acids such as glucose-1-phosphoric acid, glucose-6-phosphoric acid, glucose-1,6-diphosphoric acid, glucose-sulfate fructose-1-phosphoric acid, fructose-6-phosphoric acid, etc. Esters and their Na.

Examples of Ba include ammonium salts, myo-inositol-1-phosphoric acid, phosphatidic acid, and the like. Particularly preferred are lactic acid, tartaric acid, citric acid, gluconic acid, or malic acid.

The organic acid-containing aqueous solution can be treated by the method of the present invention as long as it contains an amino acid and/or a soluble protein, and the above-mentioned organic acid, and is not particularly limited. The effects of the present invention are preferably exhibited in solutions containing 1% by weight or more. Examples of such organic acid-containing aqueous solutions include starch manufacturing process liquids obtained during the manufacturing process of starch such as corn, potato, sweet potato, wheat, cometa pioca, and sago, and the manufacturing process of sugar products such as starch sugar, beet sugar, and cane sugar. Examples include an aqueous solution containing an organic acid obtained in , and a fermented sugar solution. Among these, the corn sulfite soaking solution obtained in the above-mentioned corn starch manufacturing process is particularly preferably used.

The cation exchange resin used in the present invention may be any resin having a free acidic group such as sulfonic acid, carboxylic acid, or phosphonic acid in its molecule, and there are no particular restrictions on the resin substrate, shape, or manufacturing method.

Such cation exchange resins generally include (1) commercially available Duolite C-20, Duolite C-26, Amberlite IR-120, Amberlite 200 (manufactured by Rohm and Haas), Diaion; 5K-
IB (manufactured by Mitsubishi Kasei Corporation), Downic 50, Downic M
-3Q in the molecule such as PC-1 (manufactured by Dow Chemical Company)
,) Ion exchange resin having I, (2) Commercially available Duolite C-464, Imac 2-5
, Amberlight IRC-50 (ROHM &
Haas Corporation), Sumikaion KC-506, KC-50
(3) Commercially available Duolite C-467, Sumikylate MC-95 (manufactured by Rohm and Haas) (Sumitomo Chemical) Examples include ion-exchange resins having -po3L in the molecule, such as (manufactured by Co., Ltd.).

The aqueous solution containing the organic acid and the cation exchange resin are generally brought into contact at a temperature of room temperature or higher, preferably 20 to 90°C. The contact method is not particularly limited, and examples include a method of immersing a cation exchange resin in an aqueous solution containing an organic acid, a method of passing an aqueous solution containing an organic acid into a column filled with a cation exchange resin, etc. is generally adopted. A method in which the organic acid-containing aqueous solution is passed through a column filled with a cation exchange resin is preferably used because the treatment operation is easy.

The amount of cation exchange resin used varies depending on the composition of the solution containing the organic acid to be treated, the type of ion exchange resin used, etc., and is set appropriately according to each condition, but in general, preferably 0.5 of cationic impurities
An amount corresponding to an exchange capacity of double equivalents or more is used.

The organic acid-containing aqueous solution treated with the cation exchange resin is subsequently subjected to the next step of treatment with an anion exchange resin.

Therefore, metal ions and amino acids are adsorbed on the cation exchange resin after the above treatment, so the adsorbed metal ions and amino acids are eluted and removed by washing with water and softening the eluent in contact with the cation exchange resin. Afterwards, it is reused.

The eluent is not particularly limited as long as it can elute adsorbed metal ions and amino acids, but an aqueous solution of mineral acids such as sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid is used. The mineral acid solution used as the eluent has a concentration of about 0.1N or more, preferably an aqueous solution of 0.5 to 4N. If the concentration is less than about 0.1N, the elubility will deteriorate, which is not preferable.

The amount of eluent used, temperature, and contact time are not particularly limited, and vary depending on the type and concentration of the eluent, the type of ion exchange resin, the type and amount of adsorbed metal ions and amino acids, and may be adjusted as appropriate. It can be set by conducting preliminary experiments.

The contact method is not particularly limited either, and a method similar to that used for the treatment of the amino acid-containing aqueous solution and the cation exchange resin may be employed.

The cation exchange resin eluted and regenerated by this method is reused as it is or after being washed with water as necessary.

A treated aqueous solution obtained by contacting an aqueous solution containing an organic acid with a cation exchange resin is contacted with an anion exchange resin to cause the organic acid to be adsorbed onto the anion exchange resin. The anion exchange resin used in the present invention may be any resin as long as it has the ability to adsorb organic acids in the aqueous solution treated with the cation exchange resin, and the resin base, shape, and manufacturing method thereof are not particularly limited. Generally, 1 in the molecule
．． A weakly basic anion exchange resin having a functional group consisting of a secondary or tertiary amino group is preferable because it has excellent adsorption to the organic acid in the treated aqueous solution, and a resin having a polyalkylene polyamino group is particularly preferably used.

As such anion exchange resin, Sumikaion ■KA
-800, Sumikaion ■KA-850, Sumikaion ■^-890 (manufactured by Sumitomo Chemical), Diaion ■WA20, Diaion ■W^10, Diaion ■CR-20 (all manufactured by Mitsubishi Chemical) ), Amberlight [F] IR-48, Amberlight @IR-45
(all manufactured by Rohm and Haas), etc.

The contact between the aqueous solution treated with the cation exchange resin and the anion exchange resin is generally carried out at room temperature or above, preferably at 20°C.
It is carried out at a temperature of ~90°C.

The contact method is not particularly limited, and for example, a method of immersing the anion exchange resin in the aqueous solution, a method of passing the aqueous solution into a tower filled with the anion exchange resin, etc. are employed. Generally, a method in which the aqueous solution is passed through a column filled with an anion exchange resin is preferably used because the treatment operation is easy.

The amount of anion exchange resin used varies depending on the concentration of the organic acid in the aqueous solution containing the organic acid to be treated, the type of ion exchange resin used, etc., and is appropriately set according to each condition. Generally, it is preferably used in an amount corresponding to an exchange capacity of 0.5 to 3 times the equivalent of the organic acid in the aqueous solution to be treated.

The anion exchange resin that has adsorbed the organic acid is washed with water as necessary. Thereafter, an eluent is brought into contact with the anion exchange resin to elute and recover the adsorbed organic acid.

The eluent is not particularly limited as long as it can elute the organic acid adsorbed on the anion exchange resin and separate the organic acid from the eluent, but generally sulfuric acid, hydrochloric acid, nitric acid,
An aqueous solution of a mineral acid such as phosphoric acid or a basic compound such as sodium hydroxide, potassium hydroxide, calcium hydroxide, or ammonia is used.

The eluent may contain an organic solvent as long as it does not interfere with the separation of the organic acid.

The amount of eluent used is not particularly limited and varies depending on the type and concentration of the eluent, the type of ion exchange resin, the type and amount of adsorbed organic acid, and can be determined by conducting preliminary experiments as appropriate. However, it is generally 0.5 times equivalent or more of the organic acid to be recovered, preferably 1.0 to
10 times equivalent amount is used.

The mineral acid solution used as the eluent has a concentration of about 0.1N or more, preferably an aqueous solution of 0.5 to 4N. If the concentration is less than about 0.1N, the organic acid has poor elubility, a large amount of eluent needs to be used, and it becomes difficult to separate the organic acid from the eluent, which is not preferred.

The contact temperature between the anion exchange resin adsorbing the organic acid and the eluent is not particularly limited. However, when a mineral acid is used, if the temperature is low, the organic acid may precipitate into the ion exchange resin, which is not preferable.

In addition, when recovering by cooling and crystal precipitation, it is preferable to use a small amount of an eluent such as a mineral acid to increase the concentration of organic acid in the eluent. is preferred. However, if the temperature is too high, the functional groups of the ion exchange resin will deteriorate.

Therefore, the optimal temperature varies depending on the organic acid, the type of anion exchange resin, the amount of organic acid adsorbed on the anion exchange resin, the type of eluent, the concentration, etc., and can be set appropriately through preliminary experiments. is usually carried out at a temperature of about 20-90°C.

This temperature can be reached by heating the eluent and/or by externally heating the vessel containing the anion exchange resin.

The contact time is also not particularly limited.

The contact method is not particularly limited either, for example, a method in which the eluent is passed through a column filled with an anion exchange resin that has adsorbed an organic acid, or an anion exchange resin that has adsorbed an organic acid in the eluent. A method such as soaking and then filtration separation is adopted. In general, it is preferable to pass the eluent through a column filled with an anion exchange resin that has adsorbed organic acids, from the viewpoint of operability. Especially when mineral acids are used, organic acids may precipitate during elution. If it is easy to do so, a method of passing the liquid in an upward flow is preferably used to prevent clogging due to precipitation.

When the eluent from the anion exchange resin has a low concentration of organic acid, the eluent can be used as all or part of the eluent. This method makes it possible to reduce elution costs and wastewater load, and also to obtain an eluent with a high concentration of organic acids, making it easy to recover organic acids from the eluent.

The organic acid is precipitated as crystals from the eluate obtained by the above method and is separated and recovered.

When sodium hydroxide, potassium hydroxide, etc. are used as an eluent, the resulting organic acid salt has a high solubility in water. Therefore, the problem of precipitation of organic acids, which is a concern when mineral acids are used as eluents, is eliminated, but it becomes difficult to recover organic acids from the eluent by cooling. It is necessary to adjust the pH so that the organic acid exists in a free state.

Methods for generating organic acid crystals from the eluent and separating and recovering the crystals include: 1) allowing the eluent to stand still, 2) cooling to precipitate the crystals, and 2) using a solvent that is poorly soluble for the organic acid. A method of reducing the solubility of an organic acid in addition to an eluent, causing the organic acid to precipitate as crystals, and separating and recovering the crystals;
■ A method of concentrating part or all of the eluent and separating and recovering the organic acid as crystals; ■ Adding calcium hydroxide or calcium chloride to the eluent to precipitate the poorly soluble salt of the organic acid and separating it as an organic acid salt. A known method such as a recovery method is employed, and an appropriate treatment is adopted depending on the type of organic acid, the concentration of the organic acid in the eluent, the type of the eluent, etc.

The precipitated organic acid crystals are separated and recovered from the eluent by filtration or the like.

The organic acid crystals separated and recovered by the method described above can be used as is, or if necessary, purified by recrystallization, etc.
Furthermore, by drying as necessary, the organic acid can be used for each purpose.

When a mineral acid is used as an eluent, the eluent after separating and recovering the organic acid can be reused as the eluent after adjusting the concentration if necessary.

By recycling and reusing as long as impurities do not accumulate,
The amount of eluent used and the energy for heating and cooling are reduced, and the waste water load is significantly reduced.

After eluting the organic acid, the anion exchange resin can be used as it is, or if necessary, it can be treated with water or a basic compound such as sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, ammonia, or hydrochloric acid, sulfuric acid, phosphoric acid, etc. After treatment with an aqueous solution of mineral acid, it can be used repeatedly as a basic ion exchange resin for recovering organic acids.

(Effects of the Invention) According to the method for recovering organic acids from organic acid-containing aqueous solutions of the present invention, it is possible to recover amino acids such as starch manufacturing process liquids, sugar manufacturing process liquids, sugar fermentation liquids, etc., which were conventionally difficult to economically recover. It becomes possible to recover useful organic acids from aqueous solutions containing large amounts of proteins, inorganic components, etc. using simple operating procedures and equipment.Therefore, its industrial value is extremely high.

<Examples> The present invention will be specifically described below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 Corn was soaked in sulfurous acid to remove starch, lactic acid 40g/l amino acid 4.5g/j! , inorganic metal ions 1.9g/j! , protein and other organic solid components meter 42
．． An organic acid-containing aqueous solution 21 having a composition of 2 g/l was mixed with a cation exchange resin Duolite C-26 (manufactured by Rohm and Haas) 500- and a polyester containing primary and secondary amino groups in the molecule. A cation exchange resin (C -26) → Anion exchange resin (K^
890), and the organic acid was adsorbed onto the anion exchange resin. After that, the anion exchange resin that has adsorbed the organic acid is subjected to 1N hydroxide at 25°C).
F and water 11 were passed sequentially at a passing rate S V 2hr-', totaling 2j! An eluent was obtained and the organic acid was eluted and recovered. The analysis results for each step are shown in Table 1. The numerical values in Table 1 are the contents of each component in the total amount of aqueous solution used or discharged in each step (all amounts are 2N).

(See the margins below) Table Example 2 Citric acid 129 g/42, carbohydrate needles such as glucose, xylose, arabinose, etc. 10 g/l Other organic solid components such as proteins, amino acids, etc. Total 50 g/I!,)
=, pH 2, 4, 45°C with a total composition of 6.0 g/f of inorganic metal ions such as Na", Ca", Mg", Fe"-, etc.
The organic acid-containing aqueous solution If obtained by fermentation was used as the organic acid-containing aqueous solution to be treated, and 1N hydrochloric acid 11 at 60°C was used as the eluent instead of 1N sodium hydroxide aqueous solution 11 at 25°C. When treated in the same manner as in Example 1, the total contents of citric acid, carbohydrates, organic solid components, and inorganic metal ions in the eluent 22 were each 1.
16.2g, 0.1g>, 7.2g, 0,I
g>.

Example 3 Amino acid 20g/IL-glucose 100g/11
The same treatment as in Example 1 was carried out except that the aqueous solution 51 containing 13 g/l of gluconic acid and 3.9 g/R of inorganic metal ions was used as the aqueous solution of the organic acid to be treated. The compositions of amino acids, L-glucose, and inorganic metal ions are 58.3 g and 0.1 g, respectively>
, 0.1 g>, 0.1 g>, and from Examples 1 to 3, the method of separating and recovering organic acids of the present invention contains amino acids, proteins, and inorganic components that were previously difficult to economically recover. It is clear that this method is effective for recovering organic acids from aqueous solutions.

(Margin below)

Claims (1)

[Scope of Claims] 1) An organic acid-containing aqueous solution containing an amino acid and/or soluble protein and an organic acid is contacted with a cation exchange resin, and then the aqueous solution after the treatment with the cation exchange resin is anionized. After the organic acid is adsorbed on the anion exchange resin by contact treatment with an ion exchange resin, the organic acid is eluted by contacting the anion exchange resin that has adsorbed the organic acid with an eluent. 1. A method for separating and recovering an organic acid from an aqueous solution containing an organic acid, the method comprising recovering the organic acid from an aqueous solution containing an organic acid. 2) The method for separating and recovering organic acids according to claim 1, wherein the organic acid-containing aqueous solution is a sulfurous acid soaking solution of corn. 3) The method for separating and recovering an organic acid according to claim 1, wherein the organic acid is lactic acid, tartaric acid, citric acid, malic acid or gluconic acid. 4) The method for separating and recovering organic acids according to claim 1, wherein the anion exchange resin is a weakly basic anion exchange resin having a functional group consisting of a primary, secondary or tertiary amino group. . 5) The method for recovering organic acids according to claim 4, wherein the amino group is a polyalkylene polyamino group.