JP2590222B2 - Method for producing p-toluenesulfonylacetic acid - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing P-toluenesulfonylacetic acid, which is an intermediate of diiodomethyl-P-tolylsulfone, which is useful as an industrial fungicide / fungicide. It is.

[Problems to be solved by conventional technology and invention]

As a conventional method for producing P-toluenesulfonylacetic acid, an aqueous solution of alkali chloroacetate or methyl chloroacetate is allowed to act on sodium P-toluenesulfinate,
Method for producing P-toluenesulfonylacetate or methyl P-toluenesulfonylacetate (Zhurnal Organicheshos)
j Khimii, 1984, 20, 602-608).

In the above method, sodium P-toluenesulfinate can be obtained as P-toluenesulfonylacetic acid or methyl P-toluenesulfonylacetate in aqueous alkali chloroacetate or methyl chloroacetate in N, N-dimethylformamide in water.

In the method using methyl chloroacetate, it is necessary to perform the reaction in an organic solvent such as N, N-dimethylformamide.
After N-dimethylformamide is distilled off to obtain methyl P-toluenesulfonylacetate, it is hydrolyzed with an aqueous sodium hydroxide solution, so that the operation becomes complicated.

In the method of reacting sodium P-toluenesulfinate and an aqueous solution of alkali chloroacetate to obtain P-toluenesulfonylacetic acid, the yield is as low as 50 to 60%.
Furthermore, sodium P-toluenesulfinate, which is a raw material, is disadvantageous in industrial-scale production due to its relatively high cost.

Therefore, an object of the present invention is to provide a method for producing P-toluenesulfonyl acetic acid with high yield using inexpensive raw materials in industrial-scale production.

[Means and actions for solving the problem]

The present inventors have conducted intensive studies on the above-mentioned problems, and found that P-toluenesulfonyl chloride, which is industrially easily available and inexpensive, was used as a starting material, and P-toluene was added in an aqueous solution to add P-toluene. The inventors have found that P-toluenesulfonyl acetic acid can be produced in high yield by adding chloroacetic acid to the same reaction system after preparing sodium sulfinate, and completed the present invention.

In the present invention, P-toluenesulfonyl chloride is converted to sodium P-toluenesulfinate at 50 to 120 ° C in the presence of sodium sulfite, adjusted to PH 5.0 to 7.0,
-A process for producing P-toluenesulfonyl acetic acid, characterized by adding chloroacetic acid at a temperature of 70 to 120C at a molar ratio of 1.2 to 1.6 times the amount of toluene sulphonyl chloride.

The production of P-toluenesulfonylacetic acid according to the present invention comprises:
It is performed in an aqueous solution. By dissolving or suspending sodium sulfite and an inorganic base in water by a conventional method, and adding P-toluenesulfonyl chloride thereto,
-Produce sodium toluenesulfinate.

The reaction temperature is 50-120 ° C, preferably 70-101 ° C.
It is. If the temperature is lower than 50 ° C., the reaction proceeds slowly, so that it is not effective. If it exceeds 120 ° C, it is not effective.

The amount of sodium sulfite is 1.0 to 1.4 mol based on 1 mol of P-toluenesulfonyl chloride. The amount of the inorganic base is 2.0 mol or more, preferably 2.0 to 2.4 mol, per 1 mol of P-toluenesulfonyl chloride.

Examples of the inorganic base include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogen carbonate and potassium hydrogen carbonate.

Addition of more than each has no effect on the yield or purity, and conversely increases the salt concentration in the system, which is not preferable. When the amount is small, the generation ratio of by-products increases, and P
-Not necessarily economical because the yield of sodium toluenesulfinate decreases.

The reaction time varies depending on the reaction temperature and cannot be unconditionally limited, but is 1 to 3 hours.

P-toluenesulfonylacetic acid is produced by introducing chloroacetic acid into the aqueous solution of sodium P-toluenesulfinate produced as described above.

After the production of sodium P-toluenesulfinate, the mixture may be cooled, and the crystals may be separated by filtration and used in the next step. However, it is not effective because the loss in the sodium P-toluenesulfinate filtrate is large. When an operation such as concentration is performed to reduce this loss, it is impossible to obtain high-purity sodium P-toluenesulfinate since salts present in the system are also precipitated at the same time, and it is difficult to obtain an effective solution. Not really.

Therefore, after the completion of the production of sodium P-toluenesulfinate, the production of P-toluenesulfonylacetic acid can be easily performed by adding chloroacetic acid to the same reaction system in an aqueous solution or in a solid state without losing sodium P-toluenesulfinate. Can be.

However, when chloroacetic acid is added after the completion of the production of sodium P-toluenesulfinate, chloroacetic acid is decomposed because the reaction solution is weakly alkaline, and does not participate in the intended reaction. Excessive need.

Therefore, by adjusting the PH to a weak acid with an acid,
The addition amount of chloroacetic acid can be reduced.

The acid used for pH adjustment is an inorganic acid such as hydrochloric acid or sulfuric acid or acetic acid, and the amount used varies depending on the type of PH or acid. PH to adjust
Is 5.0 to 7.0.

If the pH exceeds 7.0, the effect of suppressing the decomposition of chloroacetic acid is reduced.If the pH is less than 5.0, a large amount of acid is required for adjustment, and sodium P-toluenesulfinate becomes an unstable free acid. Therefore, the yield is reduced.

After pH adjustment, chloroacetic acid is added to produce P-toluenesulfonylacetic acid.

The reaction temperature in this case is 50 to 120 ° C., preferably 70 to 1
04 ° C. If the temperature is lower than 50 ° C., the reaction becomes slow, and the yield of P-toluenesulfonylacetic acid decreases.

If the amount of chloroacetic acid to be introduced is small, the reaction does not proceed and the reaction is not always economical, so that the amount is 1.2 to 2.0 mol, preferably 1.4 to 2.0 mol per mol of P-toluenesulfonyl chloride.
1.8 moles.

The concentration of chloroacetic acid is desirably 35 to 100%. If the concentration is lower than this, the amount of water is increased in industrial-scale production, which is not effective.

The reaction time varies depending on the reaction temperature, but is approximately 1 to
5 hours.

〔Example〕

Hereinafter, the present invention will be described specifically with reference to examples. All analytical methods are by liquid chromatography.

Example 1 596.2 g of water, 63.1 g (0.5 mol) of sodium sulfite and 84.0 g of sodium hydrogen carbonate were placed in a four-necked flask with a stirrer.
(1.0 mol) was added, the temperature was raised to 70 ° C., and 95.4 g (0.5 mol) of P-toluenesulfonyl chloride was introduced over 1 hour.

After the production of sodium P-toluenesulfinate, 2N
The pH was adjusted to 6.5 with hydrochloric acid. 75.6 g of chloroacetic acid
(0.8 mol) was dissolved in 100 g of water and introduced over 1 hour. Further, the mixture was stirred at the same temperature for 1 hour. Cool this,
Sodium hydroxide was added, and the insoluble matter was removed by filtration to give a homogeneous solution. The yield was p-toluenesulfonylacetic acid.
88.0%.

Example 2 The temperature at which P-toluenesulfonyl chloride was charged was
The procedure was performed in the same manner as in Example 1 except that the temperature was raised to 50 to 101 ° C. over 1 hour, and chloroacetic acid was introduced at 104 ° C.
As a result, the yield of P-toluenesulfonylacetic acid was 89.6%.
Met.

Example 3 It carried out similarly to Example 2 except having changed chloroacetic acid into 66.2g (0.7 mol). As a result, the yield of P-toluenesulfonylacetic acid was 86.2%.

Comparative Example 1 In Example 1, after the production of sodium P-toluenesulfinate was completed, the pH was adjusted to 9.0, and the same operation was performed. As a result, the yield of P-toluenesulfonylacetic acid was 72.5%.

Comparative Example 2 In Example 1, after the production of sodium P-toluenesulfinate was completed, the pH was adjusted to 4.5, and then the same operation was performed. As a result, the yield of P-toluenesulfonylacetic acid was 65.7%.

〔The invention's effect〕

According to the present invention, economical production can be achieved by using inexpensive and readily available P-toluenesulfonyl chloride as a raw material, and furthermore, operation such as removal of crystals in the middle is simplified, resulting in operational loss. Therefore, this is a useful production method capable of obtaining P-toluenesulfonyl acetic acid in high yield.

Claims (1)

(57) [Claims] (1) P-toluenesulfonyl chloride is converted to sodium P-toluenesulfinate at 50 to 120 ° C. in the presence of sodium sulfite, and adjusted to pH 5.0 to 7.0.
-A process for producing P-toluenesulfonyl acetic acid, characterized in that chloroacetic acid is added at 70 to 120 ° C in a molar amount of 1.2 to 1.6 times that of toluenesulfonyl chloride.