JPH111467A - Production of diiodomethyl-p-toluylsulfone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce the highly pure subject compound in a high yield by using hydrochloric acid to stabilize iodine monochloride and reacting the stabilized liquid with an aqueous solution of sodium p-toluenesulfonylacetate adjusted to the pH within a specific range. SOLUTION: (B) A hydrochloric acid solution of iodine monochloride is added to and reacted with (A) an aqueous solution of sodium p-toluenesulfonylacetate or an aqueous solution of potassium p-toluenesulfonylacetate of pH 1.0-6.0 to provide diiodomethyl-p-toluyl sulfone. Further, the reaction of the unreacted material is preferably promoted by adjusting the pH of the reaction liquid after the reaction so as to be 6.0-10.0. The component B is preferably stabilized by using HCl of 0.3-1.5 mol. per mol. of the iodine monochloride, and the concentration of the iodine monochloride in the hydrochloric acid solution of the iodine monochloride is preferably 30-65 wt.%. The component A is preferably used by adjusting the concentration so as to be 10.0-30.0 wt.%.

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, a fungicide, and the like. The present invention relates to a method for producing iodine monochloride aqueous solution of sodium toluenesulfonyl acetate or potassium p-toluenesulfonyl acetate using an aqueous solution of hydrochloric acid of iodine monochloride to suppress by-products and to produce high-purity DMTS with high yield.

[0002]

2. Description of the Related Art Conventionally, as a method for producing DMTS using iodine monochloride, a method disclosed in West German Patent No. 2065961 is known. In that patent, after adding iodine monochloride to an aqueous alkaline solution to form sodium hypoiodite,
DMTS is produced by adding p-toluenesulfonyl acetic 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, the production of mono-iodomethyl-p-tolylsulfone (hereinafter abbreviated as MMTS) as a by-product increases, which also has a disadvantage that 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, in order to stabilize iodine monochloride, a high concentration of sodium chloride or potassium chloride is required, and sodium chloride and potassium chloride are relatively expensive. It would be desirable to have a lower cost method.

Therefore, in the present invention, in a process for producing DMTS using iodine monochloride, iodine monochloride is stabilized with a less expensive substance, and valuable and expensive iodine, which is valuable worldwide, is effectively used, and high purity An object of the present invention is to provide a method capable of easily producing DMTS with high yield.

[0008]

Means for Solving the Problems The present inventors have conducted intensive studies on the above-mentioned problems, and found that it is effective to use hydrochloric acid instead of the conventional use of sodium chloride or potassium chloride in stabilizing iodine monochloride. Hydrochloric acid is also significantly less expensive than the above substances, and furthermore, after dissolving iodine monochloride in hydrochloric acid, the solution is adjusted to pH
It has been found that a high yield and high purity DMTS can be obtained by adding and reacting to an aqueous solution of sodium p-toluenesulfonyl acetate or an aqueous solution of potassium p-toluenesulfonyl acetate adjusted to 1.0 to 6.0.

As a result of further studies and studies, it is found that the pH of the solution after the above reaction is adjusted to pH 6.0 to 10.0 so that the post-reaction can be performed to further promote the reaction of unreacted substances. The present inventors have also found that expensive and valuable iodine can be used more efficiently and effectively, and have completed the present invention.

That is, the present invention relates to (1) pH 1.0 to 6.0
A method for producing DMTS, characterized in that a hydrochloric acid solution of 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 (2) pH 1.0 to 6.0.
After adding a hydrochloric acid solution of iodine monochloride to the aqueous solution of sodium p-toluenesulfonylacetate or the aqueous solution of potassium p-toluenesulfonylacetate to cause a reaction, then adjusting the pH of the reaction solution to 6.0 to 10.0 and performing the post-reaction. This is a method for producing a DMTS, which is a feature.

[0011]

DETAILED DESCRIPTION OF THE INVENTION Iodine monochloride decomposes in water to become iodine and chloric acid, and iodine is precipitated as crystals. Therefore, hydrochloric acid is used to stabilize iodine monochloride in water. The amount of hydrogen chloride used in this case is preferably in the range of 0.3 to 1.5 mol per mol of iodine monochloride. It is not preferable to use hydrochloric acid such that the amount exceeds 1.5 moles, since the amount of water is unnecessarily increased. When the amount of hydrochloric acid is less than 0.3 mol, iodine monochloride cannot be stabilized, and iodine monochloride is partially decomposed, and therefore p-toluenesulfonyl acetic acid is iodinated. In this case, the absolute amount of iodine monochloride is insufficient, and the yield of the target product is reduced.

The concentration of iodine monochloride in the iodine monochloride hydrochloric acid solution is desirably 30 to 65% by weight. If the concentration is higher than this, it becomes difficult to dissolve, and if the concentration is lower than this, 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 decrease, and if it exceeds 2.4 moles, no improvement in yield can be expected, and moreover, expensive iodine will be used more than necessary. Not economical.

In the present invention, iodination is carried out by adding the above-mentioned hydrochloric acid solution of iodine monochloride to an aqueous solution of sodium p-toluenesulfonylacetate or an aqueous solution of potassium p-toluenesulfonylacetate and reacting.

It is desirable that the concentration of the aqueous solution of sodium p-toluenesulfonyl acetate or the aqueous solution of potassium p-toluenesulfonyl acetate be 10.0 to 30.0% by weight. The pH of the aqueous solution is adjusted to acidic before adding a hydrochloric acid solution of iodine monochloride. The pH in this case is 1.0-6.0
And more preferably in the range of 1.5 to 3.5. p
If H 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 hydrochloric acid solution of iodine monochloride 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 allowed to react to carry out iodination. Do.

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 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.

Usually, p-ion is added to a solution of iodine monochloride in hydrochloric acid.
In the case of iodination of toluenesulfonylacetic acid, the pH decreases due to hydrogen chloride generated with the progress of the reaction. In such a case, as described above, p-
Toluenesulfonylacetic acid is precipitated, and the progress of the reaction is slowed. In addition, alkalinity is not desirable because iodine monochloride is decomposed.

The time required for adding the iodine monochloride solution is not fixed depending on the desired amount of DMTS to be produced, the reaction temperature and the shape of the reactor, but is usually 1 to 6 hours. After the addition of the iodine monochloride solution,
It is preferable to maintain the pH and temperature ranges described above for about 1 to 3 hours to complete the reaction.

As described above, according to the present invention, high-purity DMTS can be obtained in good yield by reducing the content of impurities, but a more preferable method is to adjust the pH of the reaction solution after the above reaction. A method of performing a post-reaction can be mentioned, and when this method is employed, DMTS can be obtained with higher yield.

That is, according to the study of the present inventors, iodine monochloride remaining in the system near the end of the reaction and iodine generated by decomposition of the iodine monochloride are particularly effective when the pH of the reaction solution is 6.0 to 10.0. Hypoiodous acid was found in the range, which was found to react with p-toluenesulfonyl acetic acid to produce DMTS.

Therefore, even when the molar ratio of iodine monochloride to p-toluenesulfonyl acetic acid used is 2.0 to 2.1, the desired DMTS production reaction can proceed almost quantitatively. It has been found that expensive and valuable iodine existing in the system can be used very efficiently.

In the above embodiment in which a post-reaction occurs,
The pH of the reaction solution is adjusted by adding sodium hydroxide, potassium hydroxide, ammonium hydroxide, or the like, or an aqueous solution thereof. In this case, if the pH of the reaction solution is less than 6.0, it is difficult to proceed with the reaction, and no further improvement in the yield of DMTS is observed.
Undesirably increases by-products.

In addition to the above, the post-reaction hardly proceeds at a temperature lower than 30 ° C., and at a temperature higher than 60 ° C., the production of MMTS is remarkably increased.
It is preferable to carry out the reaction in a temperature range of 6060 ° C., and the reaction time is usually in a range of 0.5 to 2 hours.

After the iodination of p-toluenesulfonylacetic acid as described above, the reaction solution is made alkaline for the purpose of decolorization. If the iodine color is strong, it is possible to use sodium sulfite or sodium thiosulfate as a reducing agent.However, usually, sodium hydroxide, potassium hydroxide or ammonium hydroxide is used to reduce the reaction solution. It is possible to sufficiently decolorize only by adjusting the pH to 10.0 to 14.0.

[0027]

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. At a temperature of 30 ° C. while stirring the above solution, 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. 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. Then, the pH was adjusted to 11.0 using a 20% aqueous sodium hydroxide solution, and the precipitated crystals were decolorized. The crystals were separated by filtration, washed with water and dried.
164.6 g of high-purity crystals were obtained (yield 97.5%). The content of MMTS, which is an impurity contained in the crystal, is
0.82%.

Example 2 85.6 g (0.40 mol) of p-toluenesulfonylacetate 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
162.5 g of TS crystals were obtained (yield 96.3%). In addition,
The content of MMTS, an impurity contained in the crystal, was 0.78
%Met.

Example 3 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. This solution was stirred at a temperature of 30 ° C., and 266.3 g of a 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 the same temperature for 2 hours. During this time, the pH was adjusted to 2.0 to 3.0. Next, the pH was adjusted to 8.5 with a 20% aqueous sodium hydroxide solution, the temperature was gradually raised, and the temperature was raised to 60 ° C. over about 40 minutes to carry out a post-reaction. During this time, the pH was adjusted to 8.5. When the post-reaction was completed, 5 g of sodium thiosulfate was added and stirring was continued at the same temperature for 2 hours to decolorize the precipitated crystals. The crystals were collected by filtration, washed with water, and dried to obtain 168.0 g of high purity crystals of DMTS (yield 99.5%). The content of MMTS, which is an impurity contained in the crystal, was 0.94%.
Met.

COMPARATIVE 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 aqueous solution was adjusted to pH 6.0 with 2N hydrochloric acid. A solution prepared by dissolving 138 g (0.85 mol) of iodine monochloride in 182.1 g of a 26% aqueous sodium chloride solution was added to the above solution at 30 ° C. over 1 hour to react. The pH dropped during the addition. So, 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 the same temperature for 2 hours. During this time, the pH was adjusted to 2.0 to 3.0. 20% after reaction
The pH of the reaction solution was adjusted to 11.0 using an aqueous sodium hydroxide solution, and the precipitated crystals were decolorized. The crystals were separated by filtration, washed with water, and dried, whereby 163.5 g of high-purity DMTS crystals were obtained (96.9% yield). Note that the content of MMTS, which is an impurity contained in the crystal, was 0.85%.

Comparative Example 2 The procedure of Comparative Example 1 was repeated, except that an aqueous solution of iodine monochloride / sodium chloride was added and the pH during the reaction was changed to 12.0. As a result, 117.7 g of DMTS crystals (69.7% yield) were obtained. Note that the content of MMTS, which is an impurity contained in the crystal, was 6.82%.

[0033]

According to the present invention, iodine monochloride can be stabilized by using relatively inexpensive hydrochloric acid.
The production cost can be reduced, and very high-purity DMTS can be produced with high yield. Further, when the post-reaction operation described in the present invention is employed, it is possible to produce DMTS with a yield value well over 99%, which is more valuable than conventionally known production methods. Iodine, which is a resource, can be more effectively used.

 ──────────────────────────────────────────────────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 (2)

[Claims] An iodine monochloride hydrochloric acid solution is added to and reacted with an aqueous solution of sodium p-toluenesulfonyl acetate or an aqueous solution of potassium p-toluenesulfonyl acetate having a pH of 1.0 to 6.0. Production method. 2. An aqueous solution of sodium i-chloride of iodine monochloride is added to an aqueous solution of sodium p-toluenesulfonyl acetate or an aqueous solution of potassium p-toluenesulfonyl acetate having a pH of 1.0 to 6.0 to cause a reaction. Diiodomethyl-
A method for producing p-tolylsulfone.