JPH07188104A - Production of phenoxybenzoic acid - Google Patents

Abstract

PURPOSE:To provide an industrially excellent production method for phenoxybenzoic acid as an intermediate for producing agrochemicals, medicines and dye, etc. CONSTITUTION:In a method for producing phenoxybenzoic acid by reacting a halobenzoic acid with phenol, a caustic alkali is added to a mixture of the halobenzoxic acid and phenol to form a salt and the resulting material is dehydrated and mixed with a copper catalyst to efficiently produce phenoxybenzoic acid.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing phenoxybenzoic acid. More specifically, it relates to a method for producing phenoxybenzoic acid, which is its phenyl ether, from halobenzoic acid and phenol.

[0002]

BACKGROUND OF THE INVENTION Phenoxybenzoic acid, which is the object compound of the present invention, is an important compound as an intermediate for the production of agricultural chemicals, pharmaceuticals and the like. Especially as an intermediate for producing an alkoxyiminoacetic acid amide compound which is an agricultural fungicide shown in JP-A-3-246268 and an agricultural fungicide which is shown in JP-A-63-30463. It is an important compound.

Conventionally, as a method for producing this phenoxybenzoic acid, a method for producing phenoxybenzoic acid from halobenzoic acid and phenol in the presence of a metal copper catalyst is widely used. At that time, Collect. Crech. Chem.
Commun. , 34 (8), 2258-77 (196.
9), J. Am. Chem. Soc., 56 , 117 (1
934) or Ber. 37 , 854 (1904), a catalytic amount of metallic copper and caustic alkali are added to a mixture of halobenzoic acid and phenol, and the mixture is heated to a predetermined reaction temperature and reacted to produce phenoxybenzoic acid. The method is generally used.

However, according to these methods, the yield of phenoxybenzoic acid, which is the target for producing hydroxybenzoic acid as a by-product by hydroxylation of the starting halobenzoic acid in the reaction system, is as low as 60 to 66%. . Therefore, the conventional method for producing phenoxybenzoic acid requires a purification operation such as recrystallization or silica gel column chromatography and complicates the production process, and thus cannot be said to be an industrial method.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to find and provide a method for producing industrially useful phenoxybenzoic acid, in addition to the above-mentioned known techniques.

[0006]

Means for Solving the Problems In the method for producing phenoxybenzoic acid, which is a phenyl ether thereof, from halobenzoic acid and phenol, the present inventors have further improved productivity, and have a high yield and high quality. The method for producing the desired phenoxybenzoic acid was intensively studied. As a result, they have found and completed a method for producing phenoxybenzoic acid of the present invention. That is, in the method of producing phenoxybenzoic acid by reacting halobenzoic acid with phenol, a caustic alkali is added to a mixture of halobenzoic acid and phenol to form a salt, and after dehydration, a high yield is obtained by adding a copper catalyst. It was found that phenoxybenzoic acid can be produced by. Further, it was found that a high-purity phenoxybenzoic acid can be obtained only by a simple water washing treatment and solvent removal without performing a complicated purification operation such as recrystallization or silica gel chromatography of the phenoxybenzoic acid, and completed the present invention. did.

That is, the method of the present invention is a method for producing phenoxybenzoic acid by reacting halobenzoic acid with phenol, in which a caustic alkali is added to a mixture of halobenzoic acid and phenol to form a salt, which is then dehydrated to give copper. This is a method for producing phenoxybenzoic acid in high yield by adding a catalyst. According to this method, the obtained phenoxybenzoic acid can be obtained as a high-purity product by simple washing with water and evaporation of the solvent without performing a complicated purification operation such as recrystallization or silica gel chromatography.

More specifically, the method of the present invention comprises adding a predetermined amount of caustic alkali to a mixture obtained by dissolving or suspending halobenzoic acid and phenol, followed by dehydration and then adding a copper catalyst to a predetermined amount. React at temperature. The charging sequence of the raw materials other than this is not preferable because it leads to a decrease in the yield and quality of the phenoxybenzoic acid obtained. It can be isolated by steam distillation of the reaction solution obtained after completion of the reaction, or by neutralizing the caustic and then extracting with an organic solvent in which the target compound phenoxybenzoic acid is easily soluble and distilling off the solvent. it can. The yield of phenoxybenzoic acid in the obtained product in terms of purity is extremely high as compared with the prior art, 95% or more, and since hydroxybenzoic acid, which is a by-product in the prior art, is hardly produced, its isolation In that case, no complicated purification operation is required.

The method of the present invention reacts halobenzoic acid with phenol to produce phenoxybenzoic acid. The halobenzoic acid used is specifically 2-chlorobenzoic acid,
2-bromobenzoic acid, 2-iodobenzoic acid, 3-chlorobenzoic acid, 3-bromobenzoic acid, 3-iodobenzoic acid,
4-chlorobenzoic acid, 4-bromobenzoic acid, 4-iodobenzoic acid and the like.

In the method of the present invention, the amount of phenol and halobenzoic acid used is 0.8 to 4.0 mole ratio of phenol to halobenzoic acid, preferably 1.0 to 3.
It is in the range of 0 molar ratio.

As the caustic alkali to be used, either sodium hydroxide or potassium hydroxide can be used, and the caustic alkali is used in a molar ratio of 0.8 to 1.5 with respect to halobenzoic acid, and preferably 0. It is in the range of 95 to 1.3 molar ratio. Further, the caustic used may be added to the reaction system in the form of solid or aqueous solution.

In the method of the present invention, a predetermined amount of caustic alkali is added to a mixture obtained by dissolving or suspending the above halobenzoic acid and phenol to form a salt, followed by dehydration. The dehydration operation is usually carried out by azeotropic dehydration with an aromatic hydrocarbon solvent. The solvent used is inert to the raw materials and products, and is not particularly limited as long as it is azeotropic with water. Specific examples thereof include benzene, toluene, xylene, ethylbenzene, cumene, chlorobenzene and chlorotoluene. These solvents are usually used alone, but there is no problem in using two or more kinds of solvents together. The organic solvent used for the azeotropic dehydration does not have to be completely distilled off after the completion of the dehydration, and there is no problem even if it remains until the end of the reaction. The amount of the aromatic hydrocarbon solvent used in the method of the present invention is 0.2 to 3.0 times by weight, preferably 0.5 to 2.0 times by weight that of the raw material halobenzoic acid. Is the range. If the amount of this aromatic hydrocarbon solvent used is extremely small, the dehydration time becomes long, and if it is too large, the volumetric efficiency of the reaction decreases and the solubility of the alkali metal salt of phenol formed as an intermediate decreases. Is also not preferable.

After dehydration, a copper catalyst is added and the reaction is carried out at a predetermined temperature. The copper catalyst used is, specifically, metallic copper, cuprous chloride, cuprous bromide, cuprous iodide, cuprous sulfate, cuprous nitrate, copper acetylacetonate complex or the like. . The amount of these copper catalysts used is 0.0001 to 0.10 mol ratio with respect to halobenzoic acid, and preferably 0.1.
It is in the range of 0005 to 0.01 molar ratio.

In the method of the present invention, if the reaction temperature is too low, the reaction rate is slow, so 120 ° C. or higher is preferable. A suitable reaction temperature range is 130 to 2
It is in the range of 00 ° C. The reaction time is not uniquely determined by the raw material concentration and the reaction temperature, but the reaction is usually completed within 5 hours, and phenoxybenzoic acid can be obtained in high yield and high quality. It should be noted that if the raw materials used in the method of the present application are extremely too little or too much, there is no problem in the reaction, but an excessive amount of the raw materials remain, which is industrially undesirable.

As described above, according to the method of the present invention, phenoxybenzoic acid, which is an intermediate for producing agricultural fungicides, can be produced from halobenzoic acid and phenol in high yield. Moreover, the obtained phenoxybenzoic acid can be easily isolated in high yield and high quality by steam distillation or extraction operation with an organic solvent. Therefore, it is a method for producing phenoxybenzoic acid, which is extremely valuable industrially.

[0016]

EXAMPLES The present invention will be further described below with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

[Example 1] 2-chlorobenzoic acid 31.4
g (0.200 mol) and phenol 37.9 g (0.4
(00 mol) was suspended in 42.5 g of toluene, and 47.1 g of a 48 wt% potassium hydroxide aqueous solution was added dropwise while maintaining the temperature at 90 to 95 ° C. with stirring. Further water content in the system 30.5
g was azeotropically dehydrated, and 18.0 g of toluene was extracted until the temperature rose to 150 ° C. After cooling the system temperature to 110 ° C or lower, 0.0475 g of cuprous chloride (0.0024 mol ratio / 2-chlorobenzoic acid) was added, the temperature was raised to 150 ° C again, and the mixture was stirred at 150 to 155 ° C for 1 hour. did. After cooling, the reaction mixture obtained was subjected to steam distillation to obtain the target compound.
42.0 g of phenoxybenzoic acid were obtained. The purity of the obtained product was 98.8%, and the yield in terms of purity based on 2-chlorobenzoic acid was 96.4%.

Example 2 2-bromobenzoic acid 40.2
When carried out in the same manner as in Example 1 using g (0.200 mol), the desired compound, 2-phenoxybenzoic acid, was added to 41.
2 g were obtained. The purity of the obtained product is 99.1%, 2
The yield in terms of purity based on -bromobenzoic acid was 95.3%.

[Example 3] 2-iodobenzoic acid 49.6
When carried out in the same manner as in Example 1 using g (0.200 mol), the target compound, 2-phenoxybenzoic acid, was converted to 43.
5 g was obtained. The purity of the obtained product is 96.5%, 2
The yield in terms of purity based on iodobenzoic acid was 98.0%.

Example 4 3-Chlorobenzoic acid 31.4
When carried out in the same manner as in Example 1 using g (0.200 mol), the target compound, 3-phenoxybenzoic acid, was converted to 43.
0 g was obtained. The purity of the obtained product is 95.9%, 3
The purity-converted yield based on -chlorobenzoic acid was 96.2%.

[Example 5] 4-chlorobenzoic acid 31.4
When carried out in the same manner as in Example 1 using g (0.200 mol), the target compound, 4-phenoxybenzoic acid, was converted to 44.
1 g was obtained. The purity of the product obtained is 94.2%, 4
The purity-converted yield based on -chlorobenzoic acid was 97.0%.

[0022]

INDUSTRIAL APPLICABILITY According to the method of the present invention, halobenzoic acid can be reacted with phenol to produce phenoxybenzoic acid in high yield and high quality, which is an industrially efficient production method.

Continuation of the front page (72) Inventor Ryuichi Mita 30 Asamu-cho, Omuta-shi, Fukuoka Mitsui Toatsu Chemical Co., Ltd.

Claims (3)

[Claims] 1. A method for producing phenoxybenzoic acid by reacting halobenzoic acid with phenol, wherein a caustic alkali is added to a mixture of halobenzoic acid and phenol to form a salt, and after dehydration, a copper catalyst is added. A method for producing phenoxybenzoic acid, which is characterized. 2. A halobenzoic acid is 2-chlorobenzoic acid,
2-bromobenzoic acid, 2-iodobenzoic acid, 3-chlorobenzoic acid, 3-bromobenzoic acid, 3-iodobenzoic acid,
The method according to claim 1, which is 4-chlorobenzoic acid, 4-bromobenzoic acid or 4-iodobenzoic acid. 3. The method according to claim 1, wherein the dehydration is azeotropic dehydration using an aromatic hydrocarbon solvent.