JP2002308823A - Method for producing phenylenedioxydiacetic acids - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of stably producing high purity phenylenedioxydiacetic acids from a mixture of phenylenedioxydiacetic acids represented by formula (1) (wherein, R is a halogen atom, a carboxy group or a 1-4C hydrocarbon group and n is an integer of 0-4) and an alkali aqueous solution. SOLUTION: The mixture of phenylenedioxydiacetic acids and the alkali aqueous solution is mixed with an acid to form crystals of the free acids of the phenylenedioxydiacetic acids which are, in turn, taken out at 35 deg.C or higher.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing phenylenedioxydiacetic acids.

[0002]

2. Description of the Related Art The general formula (I) (In the formula, R represents a halogen atom, a carboxyl group, or a hydrocarbon group having 1 to 4 carbon atoms, and n represents an integer of 0 to 4.) The phenylenedioxydiacetic acids represented by It is a compound useful as a raw material for. As a method for producing such phenylenedioxydiacetic acids, for example, Japanese Patent Application Laid-Open Nos.
General formula (II) (Wherein, R and n have the same meanings as described above), respectively, is disclosed in which a dihydroxybenzene is reacted with a halogenated acetic acid in water in the presence of an alkali compound. According to such a method, a mixture of phenylenedioxydiacetic acids and an aqueous alkali solution is obtained, and after the mixture is mixed with an acid to generate crystals of the free acid of phenylenedioxydiacetic acids, the crystals are removed. By taking it out, phenylenedioxydiacetic acids can be obtained as crystals of free acid.
It is described that it was taken out at 0 ° C. to 25 ° C.

However, according to such a method, the obtained phenylenedioxydiacetic acids have the general formula (III-1) [Wherein, R and n each have the same meaning as described above. And a compound represented by the general formula (III-2) [Wherein, R and n each have the same meaning as described above. In some cases, the compound of formula (1) may be contained as an impurity, and phenylenedioxydiacetic acids of high purity could not be produced stably.

[0004]

Accordingly, the present inventors have intensively studied to develop a method for stably producing high-purity phenylenedioxydiacetic acids from a mixture of phenylenedioxydiacetic acids and an aqueous alkali solution. As a result, when a mixture of a phenylenedioxydiacetic acid and an aqueous alkaline solution is mixed with an acid and the crystal is taken out at 20 ° C. to 25 ° C., the phenylenedioxy acid obtained when the time until mixing and taking out is long is long. It is found that the purity of diacetic acids is low, and by extracting crystals at a temperature of 35 ° C or higher, high-purity phenylenedioxydiacetic acids are stably released regardless of the time until mixing and removal. To be obtained as acid crystals,
The present invention has been reached.

[0005]

That is, the present invention relates to a method for preparing a phenylenedioxydiacetic acid free acid by mixing a mixture of a phenylenedioxydiacetic acid represented by the general formula (I) and an aqueous alkali solution with an acid. After generating crystals, 3
An object of the present invention is to provide a method for producing phenylenedioxydiacetic acids, wherein crystals of a free acid of phenylenedioxydiacetic acids are taken out at a temperature of 5 ° C. or more.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the phenylenedioxydiacetic acids represented by the general formula (I), R represents a halogen atom, a carboxyl group or a hydrocarbon group having 1 to 4 carbon atoms.
Here, examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom. The carboxyl group may form a salt by its hydrogen atom being ionized. Examples of the hydrocarbon group include an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, and a t-butyl group.
n is an integer of 0 to 4, preferably 0. When n is 2 or more, Rs may be the same as each other;
They may be different from each other.

The phenylenedioxydiacetic acids include, for example, 1,3-phenylenedioxydiacetic acid, 1,4
-Phenylenedioxydiacetic acid, 1,2-phenylenedioxydiacetic acid, 3-carboxymethoxy-2-chloro-phenoxyacetic acid, 3-carboxymethoxy-4-chloro-
Phenoxyacetic acid, 3-carboxymethoxy-5-chloro-phenoxyacetic acid, 2-carboxymethoxy-3-chloro-phenoxyacetic acid, 2-carboxymethoxy-4-chloro-phenoxyacetic acid, 4-carboxymethoxy-2-
Chloro-phenoxyacetic acid, 5-carboxymethoxy-
2,3-dichloro-phenoxyacetic acid, 5-carboxymethoxy-2,4-dichloro-phenoxyacetic acid, 4-carboxymethoxy-2,3-dichloro-phenoxyacetic acid,
5-carboxymethoxy-2,3,4-trichloro-phenoxyacetic acid, 3-carboxymethoxy-2-methyl-
Phenoxyacetic acid, 3-carboxymethoxy-4-methyl-phenoxyacetic acid, 3-carboxymethoxy-5-methyl-phenoxyacetic acid, 2-carboxymethoxy-3-methyl-phenoxyacetic acid, 2-carboxymethoxy-4-
Methyl-phenoxyacetic acid, 4-carboxymethoxy-2
-Methyl-phenoxyacetic acid, 5-carboxymethoxy-
2,3-dimethyl-phenoxyacetic acid, 5-carboxymethoxy-2,4-dimethyl-phenoxyacetic acid, 5-carboxymethoxy-2-chloro-3-methyl-phenoxyacetic acid, 4-carboxymethoxy-2-chloro-3- Methyl-phenoxyacetic acid and the like.

The aqueous alkali solution in the mixture of the phenylenedioxydiacetic acids and the aqueous alkali solution is an aqueous solution containing an alkali metal compound and showing alkalinity. Examples of the alkali metal compound include sodium hydroxide,
Examples thereof include alkali metal hydroxides such as potassium hydroxide, and alkali metal carbonates such as sodium carbonate and potassium carbonate. Preferred are alkali metal hydroxides.
The pH of the aqueous alkali solution in the mixture is usually about 7.5 or more, preferably about 12 or less, and more preferably about 8.5 or less. The content of water in the aqueous alkaline solution is usually 1 to 8 times by weight, and preferably 2 to 5 times by weight, based on the phenyleneoxydiacetic acid. When the content of water exceeds 8 times by weight, the amount of phenylenedioxydiacetic acids dissolved in the mixture after mixing with the acid increases, and the yield of the obtained phenylenedioxydiacetic acids tends to decrease. .

[0009] In such a mixture, the phenylenedioxydiacetic acids may be entirely dissolved or may be partially dissolved and partially dissolved without being dissolved.

A mixture of a phenylenedioxydiacetic acid and an aqueous alkali solution may be obtained by mixing a phenylenedioxydiacetic acid and an aqueous alkali solution. It can also be obtained by reacting with a halogenated acetic acid in water in the presence of a compound (Japanese Patent Application Laid-Open (Kokai) Nos. 4-173765 and 4-173765).

The dihydroxybenzenes represented by the general formula (II) include, for example, resorcin, catechol, hydroquinone, 2-chloro-benzene-1,3-
Diols, 4-chloro-benzene-1,3-diol,
5-chloro-benzene-1,3-diol, 3-chloro-benzene-1,2-diol, 4-chloro-benzene-1,2-diol, 2-chloro-benzene-1,4-diol
Diols, 4,5-dichloro-benzene-1,3-diol, 2,4-dichloro-benzene-1,3-diol, 2,3-dichloro-benzene-1,4-diol,
4,5,6-trichloro-benzene-1,3-diol, 2-methyl-benzene-1,3-diol, 4-methyl-benzene-1,3-diol, 5-methyl-benzene-1,3-diol Diol, 3-methyl-benzene-1,
2-diol, 4-methyl-benzene-1,2-diol, 2-methyl-benzene-1,4-diol, 4,5
-Dimethyl-benzene-1,3-diol, 2,4-dimethyl-benzene-1,3-diol, 4-chloro-5
-Methyl-benzene-1,3-diol, 2-chloro-
3-methyl-benzene-1,4-diol and the like.

Examples of the halogenated acetic acid include monohalogenated acetic acids such as monochloroacetic acid and monobromoacetic acid. The amount of the halogenated acetic acid to be used is usually about 2 to 4 mol times, preferably 2.2 to 3 mol times, relative to dihydroxybenzenes. It is about mole times.

As the alkali metal compound, the same alkali metal compound as described above is used. The amount of the alkali metal compound to be used is usually 1.8 to 2.
It is about 5 mole times, preferably about 1.9 to 2.1 mole times.

The amount of water used is usually about 2 to 15 times, preferably about 4 to 9 times the weight of dihydroxybenzenes.

In order to react the dihydroxybenzenes with the halogenated acetic acid, for example, a halogenated acetic acid and an alkali metal compound may be added to a mixture of the dihydroxybenzenes and water. A mixture of dihydroxybenzenes and water is usually an aqueous solution of dihydroxybenzenes dissolved therein. The alkali metal compound is usually added as its aqueous solution. The mixture of dihydroxybenzenes and water may contain an alkali metal compound in advance. The halogenated acetic acid and the alkali metal compound are usually added simultaneously to a mixture of dihydroxybenzenes and water.

A mixture of a dihydroxybenzene, an alkali metal compound and water and a halogenated acetic acid may be simultaneously added to a vessel and mixed. A mixture of dihydroxybenzenes, alkali metal compounds, and water is usually an aqueous solution of these compounds in which the dihydroxybenzenes and alkali metal compounds are dissolved.

The reaction temperature is usually from 80 ° C to 110 ° C,
Preferably, the temperature is in the range of 90 ° C to 100 ° C.
The reaction may be usually performed until the halogenated acetic acid disappears,
The reaction time is usually about 1 to 10 hours.

Thus, the dihydroxybenzenes are etherified with the halogenated acetic acid to form phenylenedioxydiacetic acids, and the reaction mixture after the reaction is a mixture of phenylenedioxydiacetic acids and an aqueous alkali solution.

A mixture of phenylenedioxydiacetic acids and an aqueous alkali solution is obtained by reacting a dihydroxybenzene represented by the general formula (II) with ethylene oxide in water in the presence of an alkali metal compound and then oxidizing the mixture. (Japanese Patent Publication No. Sho 62-28940, Tokuhei Hei 3)
-500653, JP-A-3-38544 and the like).

In the production method of the present invention, the mixture of the phenylenedioxydiacetic acids and the aqueous alkali solution is mixed with an acid. To mix a mixture of phenylenedioxydiacetic acids and an aqueous alkali solution with an acid, for example, a mixture of a phenylenedioxydiacetic acid and an aqueous alkali solution may be added to the acid and mixed, or An acid may be added to and mixed with the mixture of the alkali aqueous solution and the mixture of the phenylenedioxydiacetic acids and the aqueous alkali solution, and the acid may be simultaneously added to the vessel and mixed.

As the acid, for example, mineral acids such as hydrogen chloride, nitric acid, sulfuric acid and phosphoric acid are used. The amount of the acid used is appropriately selected such that the mixture after mixing with the mixture of the phenylenedioxydiacetic acids and the aqueous alkali solution has an acidity, for example, pH 6 or less, preferably pH 5 or less.
Specifically, for example, it is about 2.6 to 3.4 mol times as much as phenylenedioxydiacetic acid in terms of an ionizable hydrogen atom of an acid, About 2.6 to 3.4 mole times when a monobasic acid such as hydrogen chloride or nitric acid is used, and 1.3 to 1.7 mole times when a dibasic acid such as sulfuric acid is used as the acid. degree,
0.8 when a tribasic acid such as phosphoric acid is used as the acid.
About 1.1 mol times. The acid is usually used as an aqueous solution thereof, and the content of the acid per 100 parts by weight of the aqueous acid solution is usually about 5 to 40 parts by weight.

The mixture of the phenylenedioxydiacetic acid and the aqueous alkali solution and the acid are usually mixed at a temperature of from 0 ° C. to the boiling point of the aqueous alkali solution. When a mixture of phenylenedioxydiacetic acids and an aqueous alkali solution is added to an acid and mixed, or when a mixture of a phenylenedioxydiacetic acid and an aqueous alkali solution and an acid are added to a container and mixed, phenylenedioxydiacetic acid is used. At least 1/10, preferably all, of the mixture of acetic acid and aqueous alkali solution is 50
Mixing with an acid at a temperature of not higher than 0 ° C., preferably not lower than 0 ° C. is preferable in that phenylenedioxydiacetic acids having higher purity can be obtained.

Thereafter, the temperature is usually from 80 ° C. to 110 ° C.,
Preferably, the temperature is kept in a temperature range of 85 ° C. or more and 95 ° C. or less. The heat retention time is usually about 0.1 to 4 hours, preferably about 0.5 to 2 hours.

A precipitate is present in the mixture after mixing with the acid, and the precipitate is a crystal of the free acid of phenylenedioxydiacetic acids.

Next, the temperature is raised to 35 ° C. or higher, and crystals of the free acid of phenylenedioxydiacetic acids are taken out. To take out the crystals, for example, the mixture after mixing may be filtered. If it is taken out at a temperature lower than 35 ° C., the purity of the resulting phenylenedioxydiacetic acids will be reduced if the time after mixing with the acid becomes long. The upper limit of the temperature at the time of taking out is not particularly limited, but if it exceeds 70 ° C., the solubility of the phenylenedioxydiacetic acids increases and the yield decreases,
It is preferable to take out the crystal at 70 ° C. or lower, more preferably at 50 ° C. or lower.

After the crystals taken out by filtration are washed with water,
It may be dried. The crystals of the free acid of phenylenedioxydiacetic acids thus obtained are of high purity irrespective of the time from mixing the acid with a mixture of phenylenedioxydiacetic acids and an aqueous alkali solution until the acid is removed. Such crystals may be further purified by recrystallization or the like.

[0027]

According to the production method of the present invention, irrespective of the time from mixing a mixture of a phenylenedioxydiacetic acid and an aqueous alkali solution with an acid and removing the phenylenedioxydiacetic acid as a precipitate, Since high-purity phenylenedioxydiacetic acids can be obtained as free acid crystals, it is possible to stably obtain high-purity phenylenedioxydiacetic acids without strictly controlling the time until removal. .

[0028]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Reference Example 1 341.3 g of resorcinol in a flask under a nitrogen atmosphere.
(3.1 mol) and 258.6 g of water were stirred and mixed to obtain an aqueous solution of resorcinol, to which was added an aqueous sodium hydroxide solution (sodium hydroxide content: 48% by weight) to adjust the pH in the system to 8. 0 and an aqueous solution of sodium hydroxide (sodium hydroxide content: 48% by weight) was added to add p to the mixture.
The mixture is heated to 95 ° C. while adjusting so that H becomes 8.0, and an aqueous sodium hydroxide solution (sodium hydroxide content is 48% by weight) is added to adjust the pH of the mixture to 8.0 to 8.5. Monochloroacetic acid 74 at the same temperature while adjusting
A mixture of 7.0 g (7.9 mol) and 438.7 g of water was added dropwise over 5 hours, and then an aqueous sodium hydroxide solution (sodium hydroxide content was 48% by weight).
Was added thereto, and the mixture was stirred at the same temperature for 2 hours while adjusting the pH of the mixture to 8.0 to 8.5. The resulting reaction mixture was emptied from the flask, and 1,3-phenylenedioxydiacetic acid and alkali were added. A mixture of aqueous solutions (3097 g) was obtained. This mixture was a slurry. The total amount of the aqueous sodium hydroxide solution used was 1,318 g (sodium hydroxide was 15.8 mol).

Reference Example 2 An aqueous solution of hydrogen chloride (dilute hydrochloric acid, 10
(The hydrogen chloride content per 0 parts by weight is 10 parts by weight) 32
While stirring 8.1 g (0.9 mol of hydrogen chloride), 301.5 g (0.3 mol as resorcinol) of the mixture of 1,3-phenylenedioxydiacetic acid and the aqueous alkali solution obtained in Reference Example 1 was added thereto for 1 hour. Reference example 1
Washing water obtained by washing the flask used in the above with 33 g of water was added. When the mixture was added, the temperature gradually increased, and the temperature immediately after the addition was 32 ° C. The pH of the mixture after mixing is 1 or less.

Next, the mixture was kept at 88 ° C. for 1 hour, and then equally divided into three portions, one of which was designated as sample 1 and one was designated as sample 2.

Example 1 Sample 1 obtained in Reference Example 2 was cooled to 40 ° C., and 20 g of the sample was taken out to obtain Sample 10 (take-out time: 0 hour). After stirring at the same temperature, 20 g was taken out after 24 hours. Sample 11 (takeout time 24 hours), 20 g was taken out after 48 hours, as sample 12 (takeout time 48 hours), and 20 g was taken out after 72 hours, as sample 13 (takeout time 72 hours).

Comparative Example 1 Sample 2 obtained in Reference Example 2 was cooled to 30 ° C., and 20 g of the sample was taken out to obtain Sample 20 (take-out time: 0 hour). Sample 21 (takeout time 24 hours) was taken, and after 48 hours, 20 g was taken out and taken as sample 22 (takeout time 48 hours).

Evaluation From the samples 10 to 13 and the samples 20 to 23, precipitated crystals were taken out by filtration, washed with 6 g of water, and vacuum-dried at 60 ° C. to obtain about 2 g of white crystals. Some of the obtained crystals were analyzed by high-performance liquid chromatography (solvent: a mixed solvent of 50 parts by volume of acetonitrile and 50 parts by volume of water) by the area percentage method to obtain 1,3-phenylenedioxydioxymethane. The content of acetic acid (target), the content of 3-hydroxyphenoxyacetic acid (impurity 1) as an impurity, and 2-carboxymethyl-1,3
The total contents of -phenylenedioxydiacetic acid (impurity 2) and 4-carboxymethyl-1,3-phenylenedioxydiacetic acid (impurity 3) were determined. Table 1 shows the results.

[0035]

[Table 1]

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Jin Hara 3-1-198 Kasuganaka, Konohana-ku, Osaka-shi F-term in Sumitomo Chemical Co., Ltd. (Reference) 4H006 AA01 AA02 AC13 AD15 BC16 BC51 BJ50 BM30

Claims (3)

[Claims] 1. The compound of the general formula (I) (Wherein, R represents a halogen atom, a carboxyl group, or a hydrocarbon group having 1 to 4 carbon atoms, and n represents an integer of 0 to 4). Producing phenylenedioxydiacetic acid free acid crystals by mixing with an acid, and extracting the phenylenedioxydiacetic acid free acid crystals at a temperature of 35 ° C. or more. A method for producing acetic acids. 2. A mixture of a phenylenedioxydiacetic acid and an aqueous alkali solution represented by the general formula (II): [Wherein, R and n each have the same meaning as described above. The method according to claim 1, wherein the dihydroxybenzenes are reacted with a halogenated acetic acid in water in the presence of an alkali compound. 3. The method according to claim 1, wherein at least 1/10 of the mixture of the phenylenedioxydiacetic acid and the aqueous alkali solution is mixed with an acid at a temperature of 0 ° C. or more and 50 ° C. or less.