JP3184645B2 - Improved purification of 4-halodifluoromethoxyneophyl 3-phenoxybenzyl ethers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for purifying certain pesticidal active ingredients having insecticidal and acaricidal activity. More specifically, the present invention relates to a method for purifying 4-halodifluoromethoxyneophyl 3-phenoxybenzyl ethers.

[0002]

2. Description of the Related Art Heretofore, certain 4-halodifluoromethoxyneophyl 3-phenoxybenzyl ethers have remarkable insecticidal and acaricidal activity and have been attracting attention as new pesticides. JP-A-63-45233 discloses the following formula (3):

[0003]

Embedded image

The following formula (4)

[0005]

Embedded image

It has been described that the compound has excellent insecticidal and acaricidal activity. These compounds are similar in structure to conventional pyrethroid compounds, but differ in that pyrethroids are generally ester-type whereas pyrethroids are ether-type.

The manufacturing method is generally described in Japanese Patent Laid-Open No. 2-275.
The reaction is carried out by reacting a corresponding alkali metal salt of a phenol compound with dibromodifluoromethane or bromochlorodifluoromethane as shown in No. 831. The reaction formula is as follows.

[0008]

Embedded image

[Wherein, M represents an alkali metal, Y represents a hydrogen atom or a fluorine atom. Specifically, a solution prepared by dissolving a potassium salt of 4-hydroxyneophyl 3-phenoxybenzyl ether in N, N'-dimethylimidazolidinone (hereinafter abbreviated as DMI) in a dibromodifluoromethane solution at 20 ° C. Thereafter, the solution was gradually added dropwise, and then a solution in which potassium tertiary butoxide was dissolved with DMI was added dropwise while maintaining the temperature at 25 ° C.

After completion of the reaction, the reaction solution was poured into 500 ml of ice water, adjusted to pH = 5 to 6 with a dilute aqueous sulfuric acid solution, and then extracted three times with 500 ml of benzene. After drying over anhydrous (anhydrous), sodium sulfate was filtered and benzene was distilled off under reduced pressure to obtain pale yellow crude 4-bromodifluoromethoxyneophyl 3-phenoxybenzyl ether.

Alternatively, it is also obtained by removing excess dibromodifluoromethane from the reaction solution by distillation, filtering the inorganic substance in the reaction solution, and further distilling off DMI as a solvent by distillation.

This oily substance is subjected to high performance liquid chromatography.
As a result of analysis, the content of 4-bromodifluoromethoxyneophyl 3-phenoxybenzyl ether was 75%.
It is stated that the reaction yield is around 70%.

In the agricultural chemical market in recent years, it is indispensable to increase the purity of the active ingredient of an agricultural chemical, and it is difficult to use the agricultural chemical as an active ingredient with a purity of about 75%. Therefore,
Further purification is required.

However, the above-mentioned 4-bromodifluoromethoxyneophyl 3-phenoxybenzyl ether and the 4-halodifluoromethoxyneophyl 3-phenoxybenzyl ether represented by the general formula (2) do not crystallize but are easily prepared. It cannot be said that it is impossible to use means for high purification by recrystallization. Although a purification method by distillation is conceivable, it has a high boiling point, and further, these compounds are not necessarily thermally stable.

Conventionally, these compounds have been separated and purified by silica gel column chromatography to obtain the target compound with high purity. However, the use of expensive silica gel and the use of a large amount of solvent In addition, there are problems such as poor volumetric efficiency due to their large usage, and purification by silica gel column chromatography on an industrial scale is difficult.

[0016]

Means for Solving the Problems The inventor of the present invention has the general formula (2)
Based on the physical properties of the compounds described in (1) above, which are unstable to heat, the present inventors have conducted intensive studies on industrial purification methods. As a result, for example, an extraction operation is performed with an aliphatic hydrocarbon solvent such as hexane to selectively convert 4-halodifluoromethoxyneophyl 3-phenoxybenzyl ethers as represented by the general formula (2) to the aliphatic hydrocarbon side. The inventors of the present invention filed an application to find out that the compound of the general formula (2) can be purified to a high purity by performing extraction and improving the purity to about 90%, and further performing an activated carbon treatment. For example, in the compound of the general formula (2), Y is water
A crude product of 4-bromodifluoromethoxyneophyl 3-phenoxybenzyl ether (purity: 76.1%) in which a hydrogen atom, X is a bromine atom, and R is a hydrogen atom is extracted with an n-hexane solvent to obtain a crude product. The obtained n-hexane solution is passed through an activated carbon column to completely remove n-hexane from the effluent obtained to obtain 4-bromodifluoromethoxyneophyl 3-phenoxybenzyl ether having a purity of 98.0%. is there.

Thereafter, as a result of further study on the manufacturing method,
3-phenoxybenzyl 2- (4-t
ert-butoxycarbonyloxyphenyl) 2-methylpropyl ether (hereinafter abbreviated as TBC) or bis-
[4- {1,1-dimethyl-2- (3-phenoxybenzyloxy)} ethylphenyl] carbonate (hereinafter, referred to as
(Hereinafter abbreviated as BISC) during the reaction, respectively, in an amount of 0.1% to 2%.

[0018]

Embedded image

5% to 10% of a compound of the triphenyl orthoformate type (hereinafter abbreviated as trimer) represented by the following formula, and a precursor of BISC (hereinafter abbreviated as a precursor) and the like are considerably secondary. I knew it was alive.

In the subsequent investigations, it was found that especially TBC was difficult to separate by the above-mentioned purification operation, and if a large amount was formed during the reaction, the purity of 4-halodifluoromethoxyneophyl 3-phenoxybenzyl ethers finally decreased. In addition, it is found that the separation of the trimer and the precursor is relatively easy as compared with the TBC, but when the amount of the trimer and the precursor is large, the purity of the 4-halodifluoromethoxyneophyl 3-phenoxybenzyl ether finally decreases. Was.

Therefore, the present inventors conducted further studies on the purification of the compound of the general formula (2) in order to obtain a stable quality of the compound of the general formula (2). When the product is subjected to heat treatment with an aqueous hydrochloric acid solution, many of the impurities such as trimers become 4-hydroxyneophyl 3-
4-Hydroxyneophile 3, which is easily converted to phenoxybenzyl ether and BISC, and is relatively easy to separate a carbonate compound such as TBC and BISC by heat treatment with an aqueous sodium hydroxide solution. -It was found that the compound of formula (2) could be converted to phenoxybenzyl ether, and it could be purified efficiently and with high purity without decomposing the compound of the general formula (2).

For example, in the compound of the general formula (2), Y
Is a hydrogen atom, X is a bromine atom, and R is a hydrogen atom . A 4-bromodifluoromethoxyneophyl 3-phenoxybenzyl ether crude product (purity: 71.2%) is heated and stirred with a 10% aqueous hydrochloric acid solution, and then alkali-treated. Separate after neutralization,
After further heating and stirring with a 30% aqueous sodium hydroxide solution, the obtained treatment liquid was subjected to an extraction operation with a hexane solvent, the obtained hexane solution was passed through an activated carbon column, and hexane was completely removed from the obtained effluent. After removal, the purity was 98.
6% of 4-bromodifluoromethoxyneophyl 3-phenoxybenzyl ether could be obtained. The present invention has been completed based on such findings. That is, the present invention provides a compound represented by the general formula (1):

[0023]

Embedded image

[Wherein, R represents a hydrogen atom or a chlorine atom, Y represents a hydrogen atom or a fluorine atom, and M represents an alkali metal atom. The general formula (2) obtained by reacting an alkali metal salt of 4-hydroxyneophyl 3-phenoxybenzyl ether with dibromodifluoromethane or bromochlorodifluoromethane
(Formula 8)

[0025]

Embedded image

[Wherein, R represents a hydrogen atom or a chlorine atom, Y represents a hydrogen atom or a fluorine atom, and X represents a chlorine atom or a bromine atom. The crude product of 4-halodifluoromethoxyneophyl 3-phenoxybenzyl ethers represented by the formula was treated with an aqueous solution of a mineral acid in the presence or absence of an aliphatic hydrocarbon solvent, and further treated with an aqueous solution of an alkali. Thereafter, if necessary, the mixture is neutralized with an acid, and then the 4-halodifluoromethoxyneophyl 3-phenoxybenzyl ethers of the general formula (2) are extracted with an aliphatic hydrocarbon solvent. An improved method for purifying 4-halodifluoromethoxyneophyl 3-phenoxybenzyl ethers, comprising treating a hydrogen solution with activated carbon.

Specific examples of the mineral acid aqueous solution used in the present invention include hydrochloric acid, hydrobromic acid, hydrofluoric acid, hydroiodic acid, sulfuric acid, nitric acid and phosphoric acid. Industrially, hydrochloric acid and sulfuric acid are preferred from the viewpoint of their effects and economical aspects.

The concentration of the aqueous mineral acid solution of the present invention is 1% to 70%.
And preferably in the range of 5 to 50%.
The amount is 5% to 300%, preferably 25% to 150% by weight based on the crude product of the general formula (2).

The treatment temperature with the aqueous mineral acid solution of the present invention is 30 ° C.
To 120 ° C, preferably 50 ° C to 100 ° C.

The aqueous alkali solution used in the present invention is an alkali metal or alkaline earth metal hydroxide or carbonate. For example, lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, beryllium hydroxide, magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, lithium carbonate, sodium carbonate, potassium carbonate, Examples include rubidium carbonate, cesium carbonate, beryllium carbonate, magnesium carbonate, calcium carbonate, strontium carbonate, barium carbonate, and the like. Of these, sodium hydroxide and potassium hydroxide are preferred.

The concentration of the alkaline aqueous solution of the present invention is 5% to 9%.
It is performed in the range of 8%, preferably in the range of 20% to 60%. Further, the amount used is 10% to 300%, preferably 50% to 300% with respect to the crude product of the general formula (2).
120%.

The processing temperature of the alkaline processing liquid of the present invention is 3
It is carried out in the range of 0 ° C to 120 ° C, preferably 50 ° C to 1 ° C.
It is in the range of 00 ° C.

On the other hand, as a solvent for extracting a crude product of the compound represented by the general formula (2) after treatment with an aqueous alkali solution, a hydrocarbon solvent such as a linear or branched aliphatic carbon having 5 to 20 carbon atoms is used. Hydrogen or cyclic aliphatic hydrocarbon.

For example, the linear aliphatic hydrocarbon is pentane,
Hexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane,
Nonadecane, eicosane, branched aliphatic hydrocarbons are 2
-Methylpentane, 3-methylpentane, 2,2-dimethylbutane, 2,3-dimethylbutane, 2-methylhexane, 3-methylhexane, 3-ethylpentane, 2,
2-dimethylpentane, 2,2-dimethylpentane,
Examples thereof include 2,3-dimethylpentane, 2,4-dimethylpentane, 3,3-dimethylpentane, 2,2,3-triethylbutane, and 2,2,3,3-tetramethylbutane.

The alicyclic hydrocarbon includes, for example, cyclopentane, cyclohexane, cycloheptane, cyclooctane, and compounds having a substituent in these compounds. Among them, extraction with linear aliphatic hydrocarbons such as pentane, hexane, heptane, octane, and nonane has the highest purification effect, and the purification effect of activated carbon has the highest purification effect.

The extraction operation of the present invention is performed at a temperature of minus 50 ° C.
Carried out in the range of -100 ° C, preferably -20 ° C
It is in the range of 50 ° C.

If the amount of the aliphatic hydrocarbon and the alicyclic hydrocarbon is too small, impurities are dissolved in a large amount, so that the compound of the formula (2) cannot be highly purified. Is not favorable from an economic point of view.
Therefore, the use amount of the aliphatic hydrocarbon and the alicyclic hydrocarbon is in the range of 2 to 20 times by weight based on the crude product of the compound of the general formula (2). The above-mentioned aliphatic hydrocarbon and alicyclic hydrocarbon used in the present invention are usually used in a single solvent, but two or more kinds can be used in combination.

As the activated carbon used in the present invention, pulverized coal, granular coal, spherical coal, crushed coal and granulated coal are used. For example, Carbofin, Shirasagi series manufactured by Takeda Pharmaceutical Co., Ltd. (Strong, refined, properties, A, C, G, M, P,
S, DC, KL, W, EH, X-7000, X-710
0), Taiko Activated Carbon (SG) manufactured by Nimura Chemical Industry Co., Ltd.
F, SA-1000, K, KA, A, K1, AP, R
C, S5, P, W, SGS, SGA, SG, SGP, C
G48B, CG830B, CW830B, CW350
B, CW612G, CW816G), PM series manufactured by Mitsui Pharmaceutical Co., Ltd. (PM-PA, PM-PW, P
M-PW1, PM-WA, PM-KI, PM-YO, P
M-KS, PM-MO, PM-AA, PM-PE, PM
-PE, PM-CR, PM-WA, PM-SX, PM-
FZ, PM-SAY) and CAL, CPG, APC, F-300, F-400 manufactured by Toyo Calgon Co., Ltd.

Further, as long as the activated carbon is produced from wood, charcoal, coconut husk, coal or the like as a raw material, a refining effect can be recognized even if it is other than the above. Among them, Shirasagi-A, Shirasagi-B, Shirasagi-D, Shirasagi-M, Shirasagi-P, APC, CPG, SG
L, F-3000 and the like show particularly excellent purification effects.

The method of treating the aliphatic hydrocarbon solvent containing the compound of the general formula (2) obtained by the extraction operation with the aliphatic hydrocarbon solvent and the activated carbon may be a batch method or a method of passing through activated carbon filling or the like. From the industrial point of view, the method of passing the solution through the activated carbon packed tower is preferable from the viewpoint of facilities and labor saving.

The liquid may be passed through a reverse flow method or a flow-down method. The reverse flow method has a better purification effect. The liquid passing temperature is in the range of −50 ° C. to 100 ° C., preferably in the range of 0 ° C. to 50 ° C. The SV (H ^-1 ) at the time of passing the solution is in the range of 0.01 to 100. The smaller the value is, the more the purification effect is increased. However, in the case of industrial implementation, the required time is naturally limited. Therefore, it is preferable to carry out in the range of 0.05 to 10.

The shape of the activated carbon used is not particularly limited.
In consideration of ease of handling and performance, it is preferable to use granular activated carbon of about 5 to 100 mesh. The activated carbon packed tower after completion of the liquid passing can be regenerated and reused by any method,
As the method, for example, a method of regenerating a solvent such as benzene, toluene, and xylene can be adopted.

The above-mentioned activated carbon is usually used alone, but it is also possible to use two or more kinds in combination. The amount of the activated carbon is 0.1% based on the crude product of the compound of the general formula (2). ~
The range is 20 times by weight. However, if the amount of the activated carbon is too small, the adsorption of impurities is limited, and the compound of the general formula (2) cannot be highly purified, which is not preferable. Further, if too much is used, it is not preferable from the viewpoint of facilities and economics in the case of industrial implementation, and the range of 0.3 to 2 times the weight of the compound of the general formula (2) is preferable.

As a specific embodiment of the present invention, for example, the oil containing the compound of the general formula (2) obtained as described above is gradually added to an acidic aqueous solution set to a predetermined concentration while stirring. After stirring at the same temperature for 0.1 hour or more, after neutralizing with an aqueous alkali solution, the oil layer containing the compound of the general formula (2) was separated by a conventional separation operation, and the obtained oil layer was set to a predetermined concentration. After gradually adding to an aqueous alkali solution with stirring and stirring at the same temperature for 0.1 hour or more, an aliphatic hydrocarbon solvent set to a predetermined concentration is gradually added thereto with stirring, and 0.1 mL of an aliphatic hydrocarbon solvent is added at the same temperature.
After stirring for one hour or more, the aliphatic hydrocarbon solution layer is separated by various separation operations, and the obtained aliphatic hydrocarbon solution is passed at a predetermined flow rate from the bottom of a column filled with a predetermined amount of activated carbon. It suffices that the solvent is removed from the aliphatic hydrocarbon solution flowing out from the upper part by liquid. Alternatively, a method may be used in which after the aliphatic hydrocarbon solution and a predetermined amount of activated carbon are stirred for 0.1 hour or more, the activated carbon is separated by a filtration operation, and the solvent is distilled off from the obtained aliphatic hydrocarbon solution. The purity of the compound of the general formula (2) thus obtained can be improved to about 98%.

The 4-halodifluoromethoxyneophyl 3-phenoxybenzyl ethers of the general formula (2) used in the present invention include, for example, 4-bromodifluoromethoxyneophyl 3-phenoxybenzyl ether, 4-chlorodifluoromethoxy Neofil 3-phenoxybenzyl ether, 4-bromodifluoromethoxyneophyl 3-phenoxy-4-fluorobenzylether, 4-chlorodifluoromethoxyneophyl 3
-Phenoxy-4-fluorobenzyl ether; and the like, but is not limited to the compounds described herein.

[0046]

The present invention will be described below in detail with reference to examples. The analysis conditions in the high performance liquid chromatography in the examples are as follows. <High-performance liquid chromatography analysis conditions> Column YMC Pack A-312 (ODS) 6 mmφ × 15 cm Eluent CH ₃ CN / H ₂ O = 9/1 (volume ratio) Flow rate 1.0 ml / min Detector UV spectrophotometer (Wavelength 276nm)

Example 1 4-Chlorodifluoromethoxyneophyl 3-phenoki
Purification of Cibenzyl Ether A solution prepared by dissolving 118.0 g (0.3 mol) of potassium salt of 4-hydroxyneophyl 3-phenoxybenzyl ether in a solution of 248.0 g (1.5 mol) of bromochlorodifluoromethane in 250 ml of DMI. At 20 ° C. or lower. Next, 13.5 g (0.12 mol) of potassium tert-butoxide was added to this solution with a DMI of 60 m.
The solution dissolved in 1 was added dropwise while maintaining at 25 ° C. After completion of the reaction, the reaction solution was poured into 500 ml of ice water, and further
The pH was adjusted to 5 to 6 with a 0% sulfuric acid aqueous solution, and then extracted with 500 ml of benzene. The benzene phase was washed with water and dried over sodium sulfate (anhydrous). After filtration of sodium sulfate, benzene was distilled off under reduced pressure to give a pale yellow oil.
4.3 g were obtained. The oil was analyzed by high performance liquid chromatography to find that the content of 4-chlorodifluoromethoxyneophyl 3-phenoxybenzyl ether was 7%.
It was 1.9%. The obtained oil was washed with a 5% hydrochloric acid aqueous solution 2
01.5 g, and after stirring at 80 ° C. for 3 hours,
While cooling, 37 g of a 30% aqueous sodium hydroxide solution was added to neutralize the mixture, and the oil layer was separated by a separation operation. The obtained oil layer was washed with a 45% aqueous sodium hydroxide solution 13
After mixing with 4.3 g and stirring at 70 ° C. for 2 hours, the mixture was cooled. The n-hexane solvent 402.
9 g was gradually added dropwise with stirring, cooled to 5 ° C., and further stirred for 1 hour, and then the n-hexane solution layer was separated by liquid separation. Glass column (inner diameter 26mm, height 6
00 mm) and granular activated carbon (Toyo Calgon Co., Ltd., C
134.3 g of PG (12 to 40 mesh) was immersed in n-hexane in advance, and then packed in a column. Next, about 4.0 ml / min (S
V = 1.0 H ^-1 ), and the solution was passed through the column by a reverse flow method. After the transfer, 3000 ml of new n-hexane was added.
The solution was passed at a rate of about 8.0 ml / min by a reverse flow method. The n-hexane solution flowing out from the top of the column was completely distilled off of the n-hexane solvent to obtain 89.6 g of an oily substance. As a result of analyzing the obtained oil by high performance liquid chromatography, the content of 4-chlorodifluoromethoxyneophyl 3-phenoxybenzyl ether was 98.7%. The contents of the main components in the oil after each treatment operation are as shown in Table 1 (Table 1).

[0048]

[Table 1]

Comparative Example 1 4-Chlorodifluoromethoxyneophyl 3-phenoki
Purification of Cibenzyl Ether A solution prepared by dissolving 118.0 g (0.3 mol) of potassium salt of 4-hydroxyneophyl 3-phenoxybenzyl ether in a solution of 248.0 g (1.5 mol) of bromochlorodifluoromethane in 250 ml of DMI. At 20 ° C. or lower. Next, 13.5 g (0.12 mol) of potassium tert-butoxide was added to this solution with a DMI of 60 m.
The solution dissolved in 1 was added dropwise while maintaining at 25 ° C. After completion of the reaction, the reaction solution was poured into 500 ml of ice water, and further
The pH was adjusted to 5 to 6 with a 0% sulfuric acid aqueous solution, and then extracted with 500 ml of benzene. The benzene phase was washed with water and dried over sodium sulfate (anhydrous). After filtration of sodium sulfate, benzene was distilled off under reduced pressure to give a pale yellow oil.
4.3 g were obtained. The oil was analyzed by high performance liquid chromatography to find that the content of 4-chlorodifluoromethoxyneophyl 3-phenoxybenzyl ether was 7%.
It was 1.9%. The obtained oil was mixed with 134.3 g of a 45% aqueous sodium hydroxide solution, stirred at 70 ° C. for 2 hours, and then cooled. 402.9 g of an n-hexane solvent was gradually added dropwise to the obtained treatment liquid while stirring, and then 5
After cooling to 0 ° C. and further stirring for 1 hour, the n-hexane solution layer was separated by a liquid separation operation. In a glass column (inner diameter 26 mm, height 600 mm), granular activated carbon (CPG, 12 to 40 mesh, manufactured by Toyo Calgon Co., Ltd.) 134.
After immersing 3 g in n-hexane in advance, it was packed in a column. Next, the n-hexane solution obtained by the above operation was passed through the column at a rate of about 4.0 ml / min (SV = 1.0 H ^-1 ) by a reverse flow method. After the completion of the liquid feeding, 3000 ml of new n-hexane was passed at a rate of about 8.0 ml / min by a reverse flow method. The n-hexane solution flowing out from the top of the column was completely distilled off of the n-hexane solvent to obtain an oil 9
2.1 g were obtained. As a result of analyzing the obtained oil by high performance liquid chromatography, the content of 4-chlorodifluoromethoxyneophyl 3-phenoxybenzyl ether was 94.5% . The contents of the main components in the oil after the respective treatment operations are as shown in Table 2 (Table 2).

[0050]

[Table 2]

[0051]

According to the method of the present invention, impurities produced as by-products during the production of 4-halodifluoromethoxyneophyl 3-phenoxybenzyl ethers of the general formula (2) can be removed by a combination of acid treatment and alkali treatment. By decomposing the compound, the purification effect is improved more than conventional purification methods, and furthermore, 4-halodifluoromethoxyneophyl 3-phenoxybenzyl ethers of the general formula (2) having a stable purity are isolated and purified in a high yield. Therefore, it is highly valuable as an industrially useful purification method even when compared with conventional techniques.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-292233 (JP, A) JP-A-2-275831 (JP, A) JP-A-63-45233 (JP, A) JP-A 5- 170692 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C07C 43/29

Claims (8)

(57) [Claims] 1. A compound represented by the general formula (1): [Wherein, R represents a hydrogen atom or a chlorine atom, Y represents a hydrogen atom or a fluorine atom, and M represents an alkali metal atom. 4-hydroxyneophyl 3-
General formula (2) obtained by reacting an alkali metal salt of phenoxybenzyl ethers with dibromomodifluoromethane or bromochlorodifluoromethane [Wherein, R represents a hydrogen atom or a chlorine atom, Y represents a hydrogen atom or a fluorine atom, and X represents a chlorine atom or a bromine atom. The crude product of 4-halodifluoromethoxyneophyl 3-phenoxybenzyl ether represented by the formula [1] is treated with an aqueous solution of a mineral acid in the presence or absence of an aliphatic hydrocarbon solvent, and then further treated with an aqueous solution of an alkali. After that, the treatment liquid is treated with an aliphatic hydrocarbon solvent to obtain the compound of formula (2) 4
Extracting the halodifluoromethoxyneophyl 3-phenoxybenzyl ethers and subsequently treating the aliphatic hydrocarbon solution containing the compound with activated carbon; Improved purification method. 2. The method according to claim 1, wherein the aqueous mineral acid solution is hydrochloric acid or sulfuric acid. 3. The treatment temperature with a mineral acid aqueous solution is 30 to 120.
The method of claim 1, wherein the temperature is ° C. 4. The method according to claim 1, wherein the aqueous alkali solution is an alkali metal or alkaline earth metal hydroxide or carbonate. 5. The method according to claim 1, wherein the aqueous alkaline solution is an aqueous solution of sodium hydroxide or potassium hydroxide. 6. The treatment temperature with an aqueous alkali solution is 30 to 1
The method of claim 1, wherein the temperature is 20C. 7. The method according to claim 1, wherein the aliphatic hydrocarbon solvent is a linear, branched, or cyclic aliphatic hydrocarbon having 5 to 20 carbon atoms. 8. The method according to claim 1, wherein the amount of the activated carbon used is 0.1 to 20 times the weight of the compound of the general formula (2) obtained through the production process.