JPH111468A - Production of diiodomethyl-p-toluylsulfone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the subject compound in high yield and high purity by adding stabilized iodine monochloride to p-toluenesulfonylacetic acid to react the iodine monochloride with the p-toluenesulfonylacetic acid, further adjusting the pH of the reaction liquid, and treating the product with sodium thiosulfate. SOLUTION: (B) Iodine monochloride is added to and reacted with (A) an aqueous solution of sodium p-toluenesulfonylacetate or an aqueous solution of potassium p-toluenesulfonylacetate, and thereafter the reaction liquid is adjusted to pH 6.0-10.0 and treated with (C) sodium thiosulfate to provide diiodomethyl-p-toluyl sulfone. The component B is used in a state dissolved in hydrochloric acid, a sodium chloride aqueous solution or a potassium chloride aqueous solution to stabilize the component B in water. Preferably, the pH of the component A is adjusted to 1.0-6.0 before the component B is added. The component C is preferably used in 1-5 wt.% of the amount of the component B. The formation of a compound of the formula, which is a byproduct, is retarded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing diiodomethyl-p-tolylsulfone (hereinafter abbreviated as DMTS) useful as an industrial bactericide or a fungicide, and more particularly to a method for producing p-tolyl sulfone. -Iodination of aqueous solution of sodium toluenesulfonyl acetate or potassium p-toluenesulfonyl acetate with iodine monochloride, and treatment of the resulting DMTS with sodium thiosulfate suppresses by-products and collects highly pure DMTS. It relates to a method of manufacturing efficiently.

[0002]

2. Description of the Related Art Conventionally, a method disclosed in West German Patent No. 2065961 is known as a method for producing DMTS using iodine monochloride. In this patent, DMTS is produced by adding iodine monochloride to an aqueous alkaline solution to obtain sodium hypoiodite, and then adding p-toluenesulfonylacetic acid thereto.

[0003] Also, Japanese Patent No. 2590227 discloses p.
-Add iodine monochloride / sodium chloride aqueous solution or iodine monochloride / potassium chloride aqueous solution to toluenesulfonyl acetic acid, adjust the pH to 1.0 to 6.0, and iodinate.
A method for manufacturing an MTS is disclosed.

[0004]

The above-mentioned German Patent No. 20659 is mentioned.
In the method described in No. 61, iodine monochloride is dissolved in an aqueous solution of sodium hydroxide to form an aqueous solution of sodium hypoiodite, and this is used as an iodinating agent to perform iodination. In this case, since sodium hypoiodite is a relatively unstable compound, it is difficult to obtain a high-concentration aqueous solution, and therefore, when an industrial-scale production is intended, only the amount of water increases. It is not preferable.

Although it is possible to produce sodium hypoiodite relatively efficiently by adding iodine monochloride to an aqueous solution of sodium hydroxide, in practice, a part of iodic acid is produced. I do. Therefore, D
MTS requires a large excess of iodine monochloride. In addition, the reaction using sodium hypoiodite as an iodinating agent progresses slowly at a low temperature, so that the reaction is performed at a relatively high temperature. For this reason, there is a disadvantage that the amount of by-product monoiodomethyl-p-tolylsulfone (hereinafter abbreviated as MMTS) is increased, and it is difficult to obtain high-purity DMTS.

In the method described in Japanese Patent No. 2590227, highly reactive iodine monochloride is stabilized with sodium chloride or potassium chloride and used as it is, so that highly pure DMTS can be obtained in high yield. .

However, according to the study of the present inventors, iodine monochloride was stabilized with sodium chloride, potassium chloride or hydrochloric acid as an aqueous solution thereof, and when this was used as an iodinating agent, It has been found that by-products are formed due to iodine being a strong oxidizing agent. That is, it is a compound represented by the following formula (1) [formula 1] in which iodine in a DMTS molecule undergoes an oxidation reaction up to trivalent and has a structure in which iodine is added.

Embedded image

When the compound represented by the formula (1) [formula 1] is present as an impurity in the product of DMTS, there is a problem that iodine is gradually released and the crystal of the product DMTS is colored brown. .

Therefore, in the present invention, in a process for producing DMTS using iodine monochloride, high purity DMTS which does not cause coloring and does not contain the compound represented by the formula (1) is easily obtained. It is an object of the present invention to provide a method that can be manufactured.

[0010]

Means for Solving the Problems As a result of intensive studies on the above-mentioned problems, the present inventors have found that aqueous solutions of sodium p-toluenesulfonyl acetate or potassium p-toluenesulfonyl acetate can be converted to hydrogen chloride, sodium chloride or potassium chloride. By reacting with iodine monochloride dissolved in an aqueous solution and reducing the obtained reaction mixture with sodium thiosulfate, the compound represented by the above formula (1) [formula 1] by-produced in the reaction is obtained. It was found to be reduced to DMTS and sodium iodide. Further studies were conducted, and it was also confirmed that the crystals of DMTS thus obtained did not cause any coloration even in a stability test with time and a severe test, and the present invention was completed based on this fact.

That is, according to the present invention, iodine monochloride is added to an aqueous solution of sodium p-toluenesulfonyl acetate or an aqueous solution of potassium p-toluenesulfonyl acetate to cause a reaction, and then the pH of the reaction solution is adjusted to 6.0 to 10.0, and then the thiol is added. DMTS characterized by being treated with sodium sulfate
It is a manufacturing method of.

[0012]

DETAILED DESCRIPTION OF THE INVENTION Iodine monochloride decomposes in water to become iodine and chloric acid, and iodine is precipitated as crystals. Then, in order to stabilize iodine monochloride in water, it is dissolved in hydrochloric acid, an aqueous solution of sodium chloride or an aqueous solution of potassium chloride. The amount of hydrogen chloride, sodium chloride or potassium chloride used in this case is preferably in the range of 0.3 to 1.5 mol per mol of iodine monochloride. This is 1.5
Use of hydrochloric acid, sodium chloride, or potassium chloride exceeding the molar amount is not preferable because it only increases the amount of water unnecessarily. When the amount is less than 0.3 mol, iodine monochloride cannot be stabilized, and iodine monochloride is partially decomposed, and therefore, when iodizing p-toluenesulfonylacetic acid, Insufficient absolute amount of iodine monochloride results in a decrease in the yield of the target product.

In the above, in the case of a hydrochloric acid solution of iodine monochloride, the concentration of iodine monochloride is desirably 40 to 65% by weight. In the case of an aqueous solution of sodium chloride or potassium chloride, the concentration of iodine monochloride is desirably 30 to 50% by weight. At a high concentration exceeding the upper limit described herein, iodine monochloride hardly dissolves in any case, and at a low concentration below the lower limit, only the amount of water increases, which is not practical.

In the present invention, the amount of iodine monochloride used is 2.0 to 2.0 mol per mol of p-toluenesulfonylacetic acid.
2.4 moles, more preferably in the range of 2.0 to 2.2 moles. If it is less than 2.0 moles, the yield of the target DMTS will be reduced, and if it exceeds 2.4 moles, the yield cannot be improved, and moreover, since expensive iodine is used more than necessary, it is economical. Not a target.

In the present invention, the above solution of iodine monochloride is added to an aqueous solution of sodium p-toluenesulfonyl acetate or an aqueous solution of potassium p-toluenesulfonyl acetate.
The iodination is performed by reacting.

The concentration of the aqueous solution of sodium p-toluenesulfonyl acetate or the aqueous solution of potassium p-toluenesulfonyl acetate is preferably set to 10.0 to 30.0% by weight. The aqueous solution is brought to pH before adding the iodine monochloride solution.
Is adjusted to be acidic. In this case, the pH is from 1.0 to 6.0, and more preferably from 1.5 to 3.5. pH
If it exceeds 6.0, the decomposition of iodine monochloride becomes remarkable, so that iodine monochloride cannot be used effectively. When the pH is less than 1.0, p-toluenesulfonylacetic acid is liable to precipitate, and the reaction system becomes non-uniform, so that the progress of the reaction is very slow.

In the present invention, the iodine monochloride solution is added to the aqueous solution of sodium p-toluenesulfonyl acetate or the aqueous solution of potassium p-toluenesulfonyl acetate, the pH of which has been adjusted as described above, and the mixture is reacted to perform iodination.

The reaction temperature is from 10 to 40 ° C., more preferably from 20 to 35 ° C. At lower temperatures the reaction progresses slowly, and at higher temperatures the by-product MM
This is not desirable because the production ratio of TS increases and the purity of the obtained DMTS crystal decreases.

In the present invention, when iodine monochloride is added to and reacted with an aqueous solution of sodium p-toluenesulfonyl acetate or an aqueous solution of potassium p-toluenesulfonyl acetate, the pH of the reaction solution is preferably 1.0 to 6.0, more preferably 1.5 to 6.0.
Perform within 3.5. This pH adjustment is usually performed using sodium hydroxide, potassium hydroxide or ammonium hydroxide.
Alternatively, the treatment is performed using an aqueous solution thereof.

Normally, when iodination of p-toluenesulfonyl acetic acid is carried out with iodine monochloride, the pH is lowered due to hydrogen chloride generated as the reaction proceeds. As described above, p-toluenesulfonylacetic acid is precipitated, and the progress of the reaction is slowed. On the alkaline side, the decomposition of iodine monochloride occurs remarkably, which is not desirable.

The time required for adding the iodine monochloride solution is as follows:
Although it is not fixed depending on the production amount of the target DMTS, the reaction temperature, the shape of the reactor, etc., it is usually 1 to 6 hours. After the completion of the addition of the iodine monochloride solution, it is preferable to keep the temperature within the above-mentioned temperature range for about 1 to 3 hours to complete the reaction.

Next, in the present invention, the pH of the reaction solution is adjusted to
With sodium hydroxide, potassium hydroxide or ammonium hydroxide in the range of 6.0 to 10.0, more preferably
Adjust to 7.0 to 9.0 and gradually raise the temperature to 4
The temperature is adjusted to 0 to 80 ° C, more desirably 50 to 70 ° C, and a reduction treatment is performed by adding sodium thiosulfate to the reaction solution.

The amount of sodium thiosulfate to be added is 1 to 5% by weight based on the amount of iodine monochloride used in the reaction. If the amount is less than 1% by weight, the reduction reaction is extremely slow, and the compound represented by the above formula (1) [formula 1], which causes coloring over time, can be obtained.
If the amount exceeds 5% by weight, no further effect is observed.

During the reduction treatment with sodium thiosulfate,
The pH of the reaction solution is similarly adjusted to the range of 6.0 to 10.0, more preferably 7.0 to 9.0. If the pH is less than 6.0, the reducing effect of sodium thiosulfate is small, so that the reducing effect is small.
TS by-products increase, which is undesirable.

The temperature of the reduction treatment is in the range of 40 to 80 ° C.
More desirably, it is carried out at 50 to 70 ° C. If the temperature is lower than 40 ° C., the reducing effect is small, and if the temperature is higher than 80 ° C., MMTS by-products are significantly increased, which is not desirable.

In the present invention, there is no particular problem whether the sodium thiosulfate used is a hydrate or an anhydride. There is no difference in effect even when the crystals are added as they are in a solid state or when they are dissolved in water and added as an aqueous solution.

In addition, the deposited DMTS is usually colored brown in many cases because of the iodine generated by the decomposition of iodine monochloride. By performing this reduction reaction, the iodine generated is converted to sodium iodide. The color is reduced and the color is decolorized. DMTS thus obtained is taken out as slightly yellowish white crystals by filtration, washing with water, drying and the like from the reaction solution.

[0028]

EXAMPLES Hereinafter, the method for producing DMTS according to the present invention will be described more specifically with reference to examples and comparative examples. In the following, all percentages are based on weight.

Example 1 85.6 g (0.40 mol) of p-toluenesulfonylacetic acid was added to 5.0
The solution was dissolved in 400 g of an aqueous sodium hydroxide solution, and the pH of the aqueous solution was adjusted to 3.5 with 2N hydrochloric acid. 138 g of iodine monochloride was added thereto at a temperature of 30 ° C. while stirring the above solution.
(0.85 mol) dissolved in 182.1 g of a 26% aqueous sodium chloride solution was added over 1 hour to cause a reaction. Since the pH dropped during the addition, the pH was adjusted to between 2.0 and 3.0 with a 20% aqueous sodium hydroxide solution. 30 ° C after completion of addition
For 2 hours. During this time, the pH was adjusted to 2.0 to 3.0. Next, the pH of the reaction solution was adjusted to 8.5 using a 20% aqueous sodium hydroxide solution, and the temperature was gradually increased. The temperature was raised to 60 ° C. in about 40 minutes.
The pH was adjusted to maintain 8.5 even during the heating.
Next, 5.0 g of sodium thiosulfate was added to the reaction solution,
Stirring was continued for 2 hours at a temperature of 60 ° C., and the precipitated crystals were decolorized and reduced. During this reduction reaction, the pH was adjusted to maintain 8.5. The precipitated crystals were collected by filtration, washed with water, and dried to obtain DMT.
167.3 g of high purity crystals of S were obtained (99.1% yield).
Note that the content of MMTS, which is an impurity contained in the crystal, was 0.82%. Crystal analysis using high performance liquid chromatography did not detect the trivalent iodine compound represented by the formula (1) [Formula 1].

Example 2 85.6 g (0.40 mol) of p-toluenesulfonylacetic acid was added to 7.0
The procedure was performed in the same manner as in Example 1 except that the reaction was carried out by dissolving in 400 g of a 40% aqueous potassium hydroxide solution. As a result, DM
166.8 g of TS crystals were obtained (yield 98.8%). In addition,
The content of MMTS, an impurity contained in the crystal, was 0.78
%Met. Crystal analysis using high performance liquid chromatography did not detect the trivalent iodine compound represented by the formula (1) [Formula 1].

Example 3 85.6 g (0.40 mol) of p-toluenesulfonylacetate was added to 5.0
The solution was dissolved in 400 g of an aqueous sodium hydroxide solution, and the pH of the aqueous solution was adjusted to 3.5 with 2N hydrochloric acid. This solution was stirred at a temperature of 30 ° C., and 266.3 g of 50% iodine monochloride solution (containing 133.2 g (0.82 mol) of iodine monochloride and 29.9 g (0.82 mol) of hydrogen chloride) was added thereto over 1 hour. Added and reacted. Because the pH dropped during the addition,
The pH was adjusted to between 2.0 and 3.0 with a 20% aqueous sodium hydroxide solution. After completion of the addition, the mixture was stirred at a temperature of 30 ° C. for 2 hours. During this time, the pH was adjusted to 2.0 to 3.0. Next, the pH of the reaction solution was adjusted to 8.5 using a 20% aqueous sodium hydroxide solution, and the temperature was gradually increased.
The temperature was raised to 60 ° C. over 40 minutes. During this heating, the pH
Adjusted to keep 8.5. Next, 5.0 g of sodium thiosulfate was added to the above reaction solution, and stirring was continued at a temperature of 60 ° C. for 2 hours to carry out decolorization and reduction of precipitated crystals. During this reduction reaction, the pH was adjusted to maintain 8.5. The precipitated crystals were collected by filtration, washed with water, and dried.
g was obtained (99.5% yield). Note that the content of MMTS, which is an impurity contained in the crystal, was 0.94%. In the crystal analysis performed using high performance liquid chromatography, the compound represented by the above formula (1) [formula 1], which is a trivalent iodine compound, was not detected.

COMPARATIVE EXAMPLE 1 85.6 g (0.40 mol) of p-toluenesulfonyl acetic acid was added to 5.0%
The solution was dissolved in 400 g of an aqueous sodium hydroxide solution, and the pH of the aqueous solution was adjusted to 3.5 with 2N hydrochloric acid. 138 g of iodine monochloride was added thereto at a temperature of 30 ° C. while stirring the above solution.
(0.85 mol) in a solution of 182.1 g of a 26% sodium chloride solution was added over 1 hour to react. Since the pH dropped during the addition, the pH was adjusted to between 2.0 and 3.0 with a 20% aqueous sodium hydroxide solution. After completion of the addition, the mixture was stirred at a temperature of 30 ° C. for 2 hours. Also during this time, p
H was adjusted to 2.0 to 3.0. Next, the pH of the reaction solution was adjusted to 11.0 using a 20% aqueous sodium hydroxide solution, and the precipitated crystals were decolorized. The crystals were collected by filtration, washed with water, and dried.
g was obtained (96.9% yield). Note that the content of MMTS, which is an impurity contained in the crystal, was 0.85%. In the crystal analysis performed using high performance liquid chromatography, the compound represented by the above formula (1) [formula 1], which is a trivalent iodine compound, was detected in an area ratio of 3.4%.

Comparative Example 2 85.6 g (0.40 mol) of p-toluenesulfonylacetic acid was added to 5.0
The solution was dissolved in 400 g of an aqueous sodium hydroxide solution, and the aqueous solution was adjusted to pH 3.5 with 2N hydrochloric acid. While stirring the above solution at a temperature of 30 ° C., 276.0 g of a 50% iodine monochloride solution (containing 138.0 g (0.85 mol) of iodine monochloride and 31.0 g (0.85 mol) of hydrogen chloride) was added thereto over 1 hour. Added and reacted. Due to the pH drop during the addition, 20
The pH was adjusted to between 2.0 and 3.0 with a 20% aqueous sodium hydroxide solution. After completion of the addition, the mixture was stirred at a temperature of 30 ° C. for 2 hours. During this time, the pH was adjusted to 2.0 to 3.0. Next, the pH of the reaction solution was adjusted to 11.0 using a 20% aqueous sodium hydroxide solution, and the precipitated crystals were decolorized. The crystals were filtered off, washed with water and dried.
164.6 g of high purity crystals of MTS were obtained (yield 97.5).
%). Note that the content of MMTS, which is an impurity contained in the crystal, was 0.82%. In a crystal analysis performed using high-performance liquid chromatography, a trivalent iodine compound represented by the formula (1) [Formula 1] was detected in an area ratio of 4.6%.

Color Deformation Test of Obtained DMTS Crystals Using the DMTS crystals obtained in Examples and Comparative Examples, a stability test with time and a severe test were carried out under the following conditions. That is, 10 g of each DMTS crystal obtained in Examples 1 to 3 and Comparative Examples 1 and 2 was placed in a 20 ml glass screw vial, and placed in a thermostat at 25 ° C.
Monthly stability test for 40 months and 40 ℃ and 60 ℃ 1
A harsh test was conducted for a period of two months. The coloring status of each DMTS sample was observed, and the results are summarized in Table 1.

[0035]

[Table 1]

[0036]

As is apparent from the results of the above Examples and Comparative Examples and the results of the color modification test, according to the process for producing DMTS of the present invention, the compound represented by the above formula (1) It is possible to easily produce a DMTS which is free from contamination and does not cause coloring even after long-term storage.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Ryoichi Seki 1900 Togo, Mobara-shi, Chiba Mitsui Toatsu Chemicals Co., Ltd. (72) Takeshi Matsushita 1502-5 Mobara, Mobara-shi, Chiba Mariana Heights 101

Claims (1)

[Claims] An iodine monochloride is added to an aqueous solution of sodium p-toluenesulfonylacetate or an aqueous solution of potassium p-toluenesulfonylacetate to cause a reaction.
A method for producing diiodomethyl-p-tolylsulfone, wherein H is adjusted to 6.0 to 10.0 and then treated with sodium thiosulfate.