JPH1150286A - Production of high-purity organic carboxylic acid choline salt and high-purity choline - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing high-purity choline which does not contain byproducts by using an org. carboxylic acid choline salt as a raw material. SOLUTION: The org. carboxylic acid choline salt which is obtd. by bringing an aq. choline soln. contg. choline and further a compd. added with an ethylene oxide as a byproduct and tartaric acid or citric acid into reaction and does not contain the byproducts is dissolved in ultra-pure water and this aq. high- purity org. carboxylic acid choline salt soln. is subjected to an electrolytic method using a cation exchange membrane as a diaphragm, by which the aq. choline soln. not contg. the byproducts is produced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a high-purity organic carboxylic acid / choline salt and a high-purity choline, and more particularly, not only to a further expansion of use as a photoresist developer, The present invention relates to an improvement in producing high-purity choline useful as a raw material for intermediates such as pharmaceuticals, agricultural chemicals and functional materials.

[0002]

2. Description of the Related Art Choline is generally produced according to the following formula (1).

Embedded image Me is a methyl group,

As a by-product of this reaction, the following formula (2)
Are considered.

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[0004] The by-product is a product obtained by successively adding ethylene oxide to choline, and n = 1 and 2 are the main products. A conventional aqueous solution of choline contains about 2 to 3% of the above by-products with respect to choline.

The inventors of the present invention have already described "a method for producing high-purity choline carbonate or choline bicarbonate" (JP-A-8-119911).
Japanese Patent Application Laid-Open No. 8 (1996)) and "A method for producing high-purity choline"
No. 218191) proposes a new method for purifying choline utilizing molecular recognition of a host molecule during formation of an inclusion complex compound. High-purity choline is produced according to the following formula (3).

Embedded image

That is, the host molecule 1,1'-bis-
When β-naphthol and choline form an inclusion complex compound, the choline-1,1′-bis-β-naphthol inclusion complex that selectively incorporates only choline is formed as a single crystal by the molecular recognition of the host molecule. Separated. By this inclusion,
It is possible to remove impurities in the aqueous choline solution. It is proposed that high-purity choline is produced by subjecting the high-purity choline carbonate or bicarbonate aqueous solution obtained by reacting the clathrate complex with carbon dioxide to electrolysis using a cation exchange membrane as a diaphragm. I have.

[0007]

The prior art, however, requires the use of economically expensive host molecules, 1,1'-bis-.beta.-naphthol. Also,
After synthesizing the choline · 1,1′-bis-β-naphthol inclusion complex, the inclusion complex crystal is separated, and then the inclusion complex crystal is suspended in ultrapure water and reacted with carbon dioxide to form the inclusion complex. The complex is decomposed into high-purity choline carbonate or bicarbonate and 1,1'-bis-β-naphthol. Then, the host molecule 1,1'-bis-β-
Separate and collect naphthol. Finally, high-purity choline carbonate or bicarbonate aqueous solution is subjected to electrolysis using a cation exchange membrane as a diaphragm to produce high-purity choline, but the process is long and requires complicated post-treatment. Was.

The present invention provides an industrially and economically advantageous high-purity choline which can obtain high-purity choline by a simple operation using a specific organic carboxylic acid which is inexpensive and easily available as compared with the prior art. It is intended to provide a method for producing pure choline.

[0009]

According to the present invention, high purity choline is produced by subjecting high purity tartaric acid / choline salt or citric acid / choline salt to electrolysis using a cation exchange membrane as a membrane. The present invention provides a method for producing high-purity choline characterized by the following. According to the present invention, a choline aqueous solution containing a by-product is reacted with tartaric acid or citric acid to obtain high-purity tartaric acid / choline salt or citric acid / choline salt, and the resulting high-purity tartaric acid / choline salt is obtained. Or a method for producing high-purity choline by subjecting citric acid / choline salt to electrolysis using a cation exchange membrane as a membrane.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION [Action] According to the present invention, only choline in a choline aqueous solution forms a crystalline salt with a specific organic carboxylic acid such as tartaric acid or citric acid, and a by-product forms a crystalline salt. It utilizes the molecular recognition of a specific organic carboxylic acid that does not form.

An aqueous choline solution is reacted with tartaric acid or citric acid to separate high-purity tartaric acid / choline salt or citric acid / choline salt containing no by-products as crystals, and then to remove high-purity tartaric acid / choline salt or citric acid. An acid / choline salt is dissolved in ultrapure water, and the aqueous solution is subjected to an electrolysis method using a cation exchange membrane as a diaphragm to obtain high-purity choline in a cathode chamber.

The tartaric acid or citric acid recovered from the anode compartment is mixed with an aqueous solution of choline containing by-products and crystallized as an organic carboxylic acid / choline salt, thereby obtaining a high-purity free of by-products. It can be recovered as tartaric acid / choline salt or citric acid / choline salt and reused.

That is, by reacting an aqueous solution of choline containing by-products with tartaric acid or citric acid, crystals of high-purity tartaric acid / choline salt or citric acid / choline salt can be obtained.

The reaction formula of tartaric acid / choline salt is represented by the following formula (4)

Embedded image And the reaction formula of citric acid / choline salt is the following formula (5)

Embedded image It is represented by That is, the present invention is based on a novel finding based on the molecular recognition of a specific organic carboxylic acid that a by-product and tartaric acid or citric acid do not form a salt of a crystalline organic carboxylic acid / by-product.

Even with the same organic carboxylic acid, a monovalent carboxylic acid such as formic acid or acetic acid forms a uniform aqueous solution when reacted with an aqueous solution of choline, but this aqueous solution is concentrated under reduced pressure or a poor solvent such as alcohol. Cannot be added, and cooling does not allow precipitation of insoluble crystalline salts. Also,
When oxalic acid, a dibasic acid, malic acid, a hydroxy group-containing dibasic acid, or L-ascorbic acid, the same phenomenon as described above is observed. Furthermore, when salicylic acid belonging to an aromatic oxycarboxylic acid or adipic acid belonging to a dibasic acid is used, a uniform aqueous solution is formed by reacting with an aqueous solution of choline. Add the solvent,
When cooled, a salt with choline precipitates and can be separated from the solution, but when the above salt is electrolyzed, the salicylic acid and adipic acid generated are hardly soluble in water at room temperature, so they precipitate as crystals on the anode. The operation becomes complicated and is not practical.

On the other hand, when tartaric acid or citric acid is used, it reacts with a choline aqueous solution to form a uniform aqueous solution, and the aqueous solution is concentrated under reduced pressure or a poor solvent such as alcohol is added. By cooling, a crystalline salt with choline can be precipitated, and choline can be effectively isolated by electrolysis.

The resulting high-purity tartaric acid / choline salt or citric acid / choline salt is dissolved in ultrapure water, and an aqueous solution of high-purity tartaric acid / choline salt or citric acid / choline salt is dissolved in a cation exchange membrane. A high-purity aqueous solution of choline is obtained from the cathode chamber by charging the anode chamber of the chamber-type electrolytic cell and subjecting it to electrolysis. Note that tartaric acid or citric acid is recovered from the anode chamber as an aqueous solution. The aqueous solution of tartaric acid or citric acid is added with an aqueous solution of choline containing by-products and crystallized as a choline salt, thereby producing high-purity tartaric acid / choline salt or citric acid / choline salt containing no by-products. Can be collected and reused.

The electrolysis reaction of high purity tartaric acid / choline salt is represented by the following formula (6), and the electrolysis reaction of high purity citric acid / choline salt is represented by the following formula (7).

Embedded image

Embedded image

According to the present invention, since high-purity tartaric acid / choline salt or citric acid / choline salt is used as a raw material, this raw material does not contain any by-product represented by the formula (2). . Further, by subjecting a high-purity tartaric acid / choline salt or citric acid / choline salt aqueous solution to electrolysis using a cation exchange membrane as a diaphragm, choline can be obtained in an extremely high purity form. That is, the diaphragm electrolysis of the present invention breaks ionic bonds and the like forming tartaric acid / choline salt or citric acid / choline salt, and leaves a water-soluble organic carboxylic acid such as tartaric acid or citric acid in the anode chamber. Therefore, there is an advantage that the purity of the choline product obtained in the cathode chamber is extremely high.

[Raw Materials] In the present invention, as described above,
Among the organic carboxylic acid compounds, tartaric acid or citric acid, that is, a compound represented by the following formula (8) or (9) is used. Tartaric acid is d-tartaric acid, l-tartaric acid, dl-tartaric acid and meso-tartaric acid, and any of them can be used. However, considering the availability, price, solubility in water, etc. -Tartaric acid is more preferred. In addition, the following formula (8) shows d-tartaric acid.

Embedded image

Embedded image

The strongly basic compound used in the present invention is choline, and the aqueous solution of choline produced by the method of the above reaction formula (1) can be used as a raw material.

[Reaction] The production of high-purity choline according to the present invention can be carried out by the following method.

Tartaric acid or citric acid and an aqueous solution of choline are charged into a reactor at a ratio such that the molar ratio of organic carboxylic acid / choline is substantially 1/1, and the organic carboxylic acid compound is dissolved. The water is distilled off by concentration, then
After dispersing the concentrated solution in alcohol such as methanol or ethanol, or adding an alcohol solvent such as methanol or ethanol to the concentrated solution, heating and dissolving the precipitated crystals, and then cooling and crystallizing the crystals to obtain extremely high purity. High tartaric acid / choline salts or citric acid / choline salts can be isolated as crystals (Production Method 1).

Further, the organic carboxylic acid compound is dissolved in an organic carboxylic acid compound after being charged into a reactor at a ratio such that the molar ratio of organic carboxylic acid / choline is substantially 1/1, and an alcoholic solvent such as ethanol is added. Although the compound can be isolated, an extremely high-purity tartaric acid / choline salt or citric acid / choline salt is obtained by adding an alcohol solvent such as ethanol, heating and dissolving the precipitated crystals, and then cooling and crystallizing the crystals. (Production method 2). This production method is a simple and excellent method for producing a high-purity organic carboxylic acid / choline salt without the necessity of concentrating the reaction solution under reduced pressure unlike the production method 1.

The aqueous choline solution to be used is generally obtained by the method of the above formula (1) and contains a by-product of the above formula (2).

The precipitated tartaric acid / choline salt or citric acid
After filtration or centrifugation, the choline salt is washed with an alcoholic solvent such as methanol or ethanol, and dried to obtain a high-purity tartaric acid / choline salt or citric acid / choline salt containing no by-product in a yield of 85 mol% or more. It can be obtained in high yield.

The resulting high-purity tartaric acid / choline salt or citric acid / choline salt is dissolved in ultrapure water, and the resulting solution is used as an electrode. By subjecting it to decomposition, a high-purity choline aqueous solution can be obtained. In addition, tartaric acid or citric acid which is an organic carboxylic acid compound is not mixed in the aqueous solution.

In the electrolysis method of the present invention, a general electrolytic cell partitioned by a cation exchange membrane into an anode chamber and a cathode chamber is usually used. The structure of the electrolytic chamber is such that 1
A two-chamber type with one diaphragm is conceivable. The two-chamber type has a simple structure and is advantageous from the viewpoint of electrolytic voltage. The organic carboxylic acid aqueous solution collected at the anode is added with a choline aqueous solution containing a by-product, and crystallized as an organic carboxylic acid / choline salt, whereby high-purity tartaric acid / choline salt containing no by-product is added. Alternatively, it can be recovered and reused as a citric acid / choline salt.

The cation exchange membrane used in the present invention is a cation exchange membrane known per se, for example, one having a cation exchange group such as a sulfonic acid group, a carboxylic acid group and a phosphonic acid group. Those having a skeleton of a fluororesin are used. Sulfonic acid-based cation exchange membranes such as fluororesin-based <Nafion 966> or <Nafion 350> (manufactured by DuPont) can be suitably used.

As the anode used in the present invention, an electrode having a coating containing a platinum group metal or its oxide formed on a corrosion-resistant substrate or an electrode having high corrosion resistance in an oxidizing atmosphere such as magnetite can be used. . Further, as the cathode used in the present invention, a metal which is not attacked by alkali such as stainless steel and nickel can be used. These anodes and cathodes can be used in any shape such as a plate shape, a rod shape, a net shape or a perforated plate shape.

In the present invention, in the electrolysis, a high-purity tartaric acid / choline salt or citric acid / choline salt aqueous solution is supplied to the anode chamber of the electrolytic cell, ultrapure water is supplied to the cathode chamber, and a DC voltage is applied between both electrodes. At a current density of 1 to 100 A / dm ² , preferably 3 to 50 A / dm ² .
dm ² .

In the present invention, the temperature of the electrolysis is 10
It is preferably in the range of ５０50 ° C.

In the present invention, the electrolysis can be carried out by any of a batch system and a continuous system.

In the present invention, the concentration of the raw material supplied to the anode chamber is 1 to 60% by weight, preferably 5 to 50% by weight.

In the present invention, ultrapure water is supplied to the cathode chamber. At the start of electrolysis, the ultrapure water alone has low electric conductivity and is unlikely to undergo electrolysis. It is desirable to use a solution in which choline is added in a small amount, for example, about 0.01 to 5% by weight.

In the present invention, the electrolysis is desirably performed in an atmosphere of clean inert gas such as nitrogen or argon.

According to the present invention, high-purity choline can be obtained by electrolyzing a high-purity tartaric acid / choline salt or citric acid / choline salt aqueous solution as described above.

[0038]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples. After the electrolysis, tartaric acid or citric acid in the tartaric acid or citric acid aqueous solution remaining in the anode chamber is titrated with 1N-NaOH, high purity tartaric acid / choline salt or choline in high purity citric acid / choline salt is ion chromatography, High purity choline was determined by 1N-HCl titration.

(Example 1) A 48.0% by weight aqueous solution of choline 642.9 containing a by-product of the synthesis of tartaric acid / choline salt
g (2.546 mol) to 382.2 g (2.
546 mol) was added over 30 minutes while keeping the temperature inside the reactor at 28 ° C. or lower under cooling. After dissolving the tartaric acid crystals, when 1737.7 g of ethanol is added to the aqueous solution of tartaric acid / choline salt, crystals of tartaric acid / choline salt precipitate.
The mixture was heated to 0 ° C. to re-dissolve the precipitated crystals, and then the reaction solution was gradually cooled to −3 ° C. to give 694.8 g of precipitated white crystals.
Was isolated. The wet-precipitated crystals are vacuum-dried at 50 ° C., and 557.3 g (2.194 mol) of tartaric acid / choline salt crystals are obtained.
I got The yield was 86.2 mol%. NMR confirmed that the product was tartaric acid / choline salt.

(Tartaric acid / choline salt crystal data) mp
_{151-153 ℃ NMR (DMSO-d 6} ~CDCl 3)
3.27 (9H, s, (CH 3) 3 N + -, [ choline]) 3.60 (2H, m, -CH 2 CH 2 -,
[Choline]) 4.07 (2H, m, -CH 2 CH 2
-, [choline]) 4.07 (2H, m, > C H -O
H, [tartaric acid]) 6.99 (4H, bs, -COO
H, -OH [choline, tartaric acid]) → D-exchangeable. The obtained tartaric acid / choline salt crystals were analyzed by ion chromatography. The by-products contained in the aqueous choline solution were below the detection limit. Was.

(Example 2) Synthesis of a 47.68% by weight aqueous choline solution containing a by-product of synthesis of tartaric acid / choline salt 857.
To 4 g (3.374 mol), 507.7 g of tartaric acid
(3.383 mol), the temperature in the reactor was reduced to 30 under cooling.
C. or lower and added slowly. After dissolving the tartaric acid crystals, the temperature inside the reactor was kept at 47 ° C. or lower, and the mixture was concentrated under reduced pressure at 23 mmHg. The amount of distillate was 89% of the theoretical amount. After concentration, 2500 g of methanol was added to the concentrated solution, and the mixture was heated to 65 ° C. to dissolve precipitated crystals. Then, the methanol solution of tartaric acid / choline salt was slowly cooled. After crystal precipitation at 54 ° C., the mixture was cooled to −9 ° C.
3 g were isolated. The wet-precipitated crystals are dried under vacuum at 50 ° C., and 788.5 g of tartaric acid / choline salt crystals (3.110 m
ol). The yield was 92.2 mol%.

The resulting tartaric acid / choline salt crystals were
As a result of analysis by ion chromatography, the by-product contained in the aqueous choline solution was below the detection limit.

Example 3 As a high-purity tartaric acid / choline salt electrolysis cell, a flow cell type electrolysis cell having a pair of anodes and cathodes having an effective electrode area of 1.8 dm ² was used. The electrolytic cell is a fluorinated resin-based cation exchange membrane <
Nafion 350> (manufactured by DuPont) divided into an anode chamber and a cathode chamber, and the electrodes were: anode: DSE electrode, cathode: N
An i electrode was used. The anode chamber was charged with 100.0 g (0.395 mol) of high-purity tartaric acid / choline salt in 620.0 ultrapure water.
high-purity tartaric acid / choline salt aqueous solution 720.0 g
In the cathode chamber, 468.0 g (0.106 mol) of a 2.74% by weight, high-purity aqueous choline solution were charged. Electrolysis temperature: room temperature to 30 ° C., current density: 5.56 A /
Constant current electrolysis was performed at dm ² for 1.5 hours.

As a result of the electrolytic reaction, 603.3 g (0.364 mol) of a 9.06% by weight aqueous solution of tartaric acid was obtained in the anode compartment. The tartaric acid recovery was 92.2 mol%. A 9.78% by weight aqueous solution of high-purity choline 56 was placed in the cathode chamber.
7.5 g (0.458 mol) were obtained. By-products in choline were below the detection limit. The high purity choline yield in the cathode compartment was 89.2 mol%. The current efficiency of the electrolytic reaction was 62.9%.

9.06% by weight remaining in the anode chamber after electrolysis
To a solution of tartaric acid (530.0 g, 0.320 mol), a 47.8% by weight aqueous solution of choline containing a by-product, 81.1%
g (0.320 mol), water was distilled off by concentration under reduced pressure, methanol was added to the concentrated solution, and the mixture was heated to dissolve the precipitated crystals. Then, the methanol solution of tartaric acid / choline salt was slowly cooled. Next, the precipitated crystals were filtered and dried to obtain 77.8 g of tartaric acid / choline salt white crystals. The yield was 96.0 mol%, mp 148-152 ° C.

The recovered tartaric acid / choline salt crystals were
As a result of analysis by ion chromatography, the by-product contained in the aqueous choline solution was below the detection limit.

(Example 4) The same flow cell type electrolytic cell as in Example 3 was used using <Nafion 966> (manufactured by DuPont), which is a cation exchange membrane of a high purity tartaric acid / choline salt electrolyzed fluororesin. Electrolysis was performed.

In the anode chamber, high-purity tartaric acid / choline salt 50
A high-purity tartaric acid / choline salt aqueous solution (1013.0 g) obtained by dissolving 6.5 g (2.000 mol) in ultrapure water (506.5 g).
And 700.0 g of ultrapure water were charged into the cathode chamber. Electrolysis temperature: room temperature to 30 ° C., current density: 5.56 A /
Constant current electrolysis was performed at dm ² for 6 hours and 40 minutes.

As a result of the electrolytic reaction, 584.4 g of tartaric acid aqueous solution [251.9 g of tartaric acid (1.678 mol)
l), unreacted high-purity tartaric acid / choline salt 16.2 g (0.1 g).
064mol), H ₂ O316.3g] was obtained. The tartaric acid recovery was 87.1 mol%. In the cathode chamber, 1090.4 g of a 17.2% by weight high-purity choline aqueous solution was added.
(1.548 mol) was obtained. The high purity choline yield in the cathode compartment was 77.4 mol%. The current efficiency of the electrolytic reaction was 62.2%. The impurity concentration in the high purity choline aqueous solution is such that by-products in choline are below the detection limit, and Na, Cr, Ca <10 ppb, Fe, Ni <
It was less than 20 ppb.

After the electrolysis, the obtained aqueous tartaric acid solution 5 was placed in the anode chamber.
40.0 g [tartaric acid 232.8 g (1.551 mo)
l), 15.0 g of unreacted residual high-purity tartaric acid / choline salt
(0.059 mol), 292.2 g of H ₂ O], and a 37.8% by weight aqueous solution of choline containing 33.2% by weight 393.2
g (1.551 mol), while cooling,
It was kept at 0 ° C. or lower and added in 30 minutes. After the dropwise addition of the choline aqueous solution, 3500.0 g of ethanol was added to the tartaric acid / choline salt aqueous solution. After the precipitation of the tartaric acid / choline salt crystals, the reaction solution is heated to redissolve the precipitated crystals.
The mixture was gradually cooled to isolate 472.3 g of precipitated white crystals. 97. Dry the wet-precipitated crystal under vacuum at 60 ° C. for 3 hours.
390.0 g of 48% by weight tartaric acid / choline salt crystals (1.5
01 mol). The tartaric acid recovery yield was 93.2 mol%.

The recovered tartaric acid / choline salt crystals were
As a result of analysis by ion chromatography, the by-product contained in the aqueous choline solution was below the detection limit.

(Example 5) A 47.8% by weight aqueous solution of choline containing a by-product of synthesis of high-purity citric acid / choline salt 2
53.5 g (1.00 mol) of citric acid 192.0
g (1.00 mol) was cooled and the temperature in the reactor was increased to 40
C. or lower and added slowly. After dissolving the citric acid crystals, the temperature in the reactor was kept at 50 ° C. or less, and the solution was concentrated under reduced pressure. After concentration, 200 g of methanol was added to 339.5 g of the concentrated solution, and the mixture was heated to 40 ° C. to dissolve the precipitated crystals. Then, the citric acid / choline salt methanol solution is gradually cooled to 0 ° C.
After cooling, 290.8 g of precipitated white crystals were isolated.
The wet-precipitated crystals were dried under vacuum at 40 ° C. to obtain 264.9 g of citric acid / choline salt crystals. The yield was 88.6 mol%. NMR confirmed that it was a citric acid / choline salt.

(Citrate / choline salt crystal data) mp
99-103 ° C NMR (DMSO-d ₆ -CDCl
_{3) 2.72 (4H, s,} -C H 2 -COOH, [ citrate]) 3.33 (2H, m, (CH 3) 3 N + -,
[Choline]) 3.67 (2H, m, -CH 2 CH
₂ -, [choline]) 4.10 (2H, m, -CH 2 C
H ₂ -, [choline]) 9.40 (4H, bs, -CO
OH, -OH, [choline, citric acid]) → D exchangeable

When the obtained crystals of citric acid / choline salt were analyzed by ion chromatography, the by-product contained in the aqueous solution of choline was below the detection limit.

(Example 6) Electrolysis of high-purity citric acid / choline salt Electrolysis was performed using the same flow cell type electrolytic cell as in Example 3. In the anode chamber, 116.6 g (0.395 g) of the high-purity citric acid / choline salt synthesized in Example 5 was added.
mol) was dissolved in 624.8 g of ultrapure water, and 741.4 g of a high-purity citric acid / choline salt aqueous solution was placed in a cathode chamber.
470.0 g (0.10
6 mol). Electrolysis temperature: room temperature to 30
C., constant current electrolysis was performed at a current density of 5.56 A / dm ² for 1.5 hours.

As a result of the electrolytic reaction, 623.5 g (0.368 mol) of an aqueous 11.34 wt% citric acid solution was placed in the anode compartment.
was gotten. The citric acid recovery was 93.2 mol%. Further, 575.7 g (0.445 mol) of a 9.37% by weight high-purity choline aqueous solution was obtained in the cathode chamber. By-products in choline were below the detection limit. The high purity choline yield of the cathode compartment was 85.7 mol%. The current efficiency of the electrolytic reaction was 60.6%.

After electrolysis, 556.3 g (0.328 mol) of an aqueous 11.34 wt% citric acid solution obtained in the anode chamber.
And a 47.8% by weight choline aqueous solution containing by-products 8
3.2 g (0.328 mol) was added, water was distilled off by concentration under reduced pressure, methanol was added to the concentrated solution, and the mixture was heated to dissolve the precipitated crystals. Then, the citric acid / choline salt methanol solution was gradually cooled, filtered and dried to isolate 87.0 g of citric acid / choline salt white crystals. The yield was 89.8 mol%.

When the recovered citric acid / choline salt crystals were analyzed by ion chromatography, the by-products contained in the aqueous choline solution were below the detection limit.

Comparative Example 1 An experiment was performed in the same manner as in Example 1 except that formic acid was used instead of tartaric acid. When reacted with an aqueous solution of choline containing impurities, a uniform aqueous solution is formed. However, even if this aqueous solution is concentrated under reduced pressure or a poor solvent such as alcohol is added and cooled, an insoluble crystalline salt cannot be precipitated. Was.

(Comparative Example 2) An experiment was performed in the same manner as in Example 1 except that acetic acid was used instead of tartaric acid. When reacted with an aqueous solution of choline containing impurities, a uniform aqueous solution is formed. However, even if this aqueous solution is concentrated under reduced pressure or a poor solvent such as alcohol is added and cooled, an insoluble crystalline salt cannot be precipitated. Was.

Comparative Example 3 An experiment was conducted in the same manner as in Example 1 except that oxalic acid was used instead of tartaric acid. When reacted with an aqueous solution of choline containing impurities, a uniform aqueous solution is formed. However, even if this aqueous solution is concentrated under reduced pressure or a poor solvent such as alcohol is added and cooled, an insoluble crystalline salt cannot be precipitated. Was.

(Comparative Example 4) An experiment was performed in the same manner as in Example 1 except that malic acid was used instead of tartaric acid. When reacted with an aqueous solution of choline containing impurities, a uniform aqueous solution is formed. However, even if this aqueous solution is concentrated under reduced pressure or a poor solvent such as alcohol is added and cooled, an insoluble crystalline salt cannot be precipitated. Was.

Comparative Example 5 An experiment was performed in the same manner as in Example 1 except that L-ascorbic acid was used instead of tartaric acid. When reacted with an aqueous solution of choline containing impurities, a uniform aqueous solution is formed. However, even if this aqueous solution is concentrated under reduced pressure or a poor solvent such as alcohol is added and cooled, an insoluble crystalline salt cannot be precipitated. Was.

(Comparative Example 6) An experiment was performed in the same manner as in Example 1 except that salicylic acid was used instead of tartaric acid. When reacted with an aqueous solution of choline containing impurities,
Although a uniform aqueous solution was formed, the aqueous solution was concentrated under reduced pressure or a poor solvent such as alcohol was added thereto, followed by cooling to precipitate a crystalline salt of choline. However,
When this choline salt was electrolyzed in the same manner as in Example 3, it was found that salicylic acid was precipitated as crystals on the anode and was not practical.

Comparative Example 7 An experiment was performed in the same manner as in Example 1 except that adipic acid was used instead of tartaric acid. When reacted with an aqueous solution of choline containing impurities,
Although a uniform aqueous solution was formed, the aqueous solution was concentrated under reduced pressure or a poor solvent such as alcohol was added thereto, followed by cooling to precipitate a crystalline salt of choline. However,
When this choline salt was electrolyzed in the same manner as in Example 3, it was found that adipic acid was precipitated as crystals on the anode and was not practical.

[0066]

According to the present invention, an organic carboxylic acid containing no by-product obtained by reacting a choline aqueous solution containing a compound obtained by further adding ethylene oxide to choline as a by-product and tartaric acid or citric acid. By dissolving a choline salt in ultrapure water and subjecting the high-purity organic carboxylic acid / choline salt aqueous solution to an electrolysis method using a cation exchange membrane as a diaphragm, a choline aqueous solution containing no by-products can be obtained. it can. The resulting choline is a high-purity basic compound and is extremely useful in the fields of medicine, agricultural chemicals, and functional materials.

Claims (2)

[Claims] 1. A high-purity choline produced by subjecting a high-purity tartaric acid / choline salt or a high-purity citric acid / choline salt to electrolysis using a cation exchange membrane as a diaphragm to produce high-purity choline. Production method. 2. A method comprising reacting an aqueous choline solution containing a by-product with tartaric acid or citric acid, and separating the resulting high-purity tartaric acid / choline salt or high-purity citric acid / choline salt as crystals. High-purity organic carboxylic acid
Method for producing choline salt.