JPH107691A - Production of o,o-dimethyl phosphoroamidothioate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject compound useful as an intermediate for insecticides by reacting O,O-dimethyl phosphorochloridothioate with ammonia in the presence of an alkali hydroxide, as the amount of ammonia used can be reduced without waste water. SOLUTION: The reaction of O,O-dimethyl phosphorochloridothioate with ammonia is carried out by using 1-1.5 mole of ammonia and 0.8-1.1 mole of an alkali hydroxide, for example, sodium hydroxide, per mole of the O,O- dimethyl phosphorochloridothioate and heating up to 40 deg.C. Then, the reaction mixture is phase-separated into the oil layer and the aqueous layer, the reaction product is extracted from the aqueous layer with toluene or the like and the solvent is evaporated off from the extraction solution to give the objective compound. In this process, the reaction smoothly proceeds with a reduced amount of ammonia to form the objective compound useful as a raw material for production of insecticides without occurrence of waste water containing a large amount of ammonium chloride.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a process for producing O, O-dimethylphosphoramidothioate.

[0002]

2. Description of the Related Art O, O-dimethylphosphoramidothioate is well known as an intermediate for producing O, S-dimethyl N-acetylphosphoramidothioate useful as an insecticide. Also, a method of reacting O, O-dimethyl phosphorochloride thioate with ammonia is well known. (East German Patent No. 16106
No. 9)

[0003] However, this method requires not only a large amount of ammonia by 2 mol times or more than that of O, O-dimethyl phosphorochloride thioate, but also wastewater containing a large amount of by-product ammonium chloride. Therefore, the processing has been a major problem. Further, in order to effectively utilize ammonia, an ammonia recovery process for recovering ammonia from such ammonium chloride-containing wastewater is required. When using as a raw material, there is also a problem that the yield of O, O-dimethylphosphoramidothioate decreases due to impurities in the recovered ammonia.

[0004]

SUMMARY OF THE INVENTION
The present inventors have solved such a problem, and do not generate wastewater containing a large amount of ammonium chloride, and therefore do not need to recover ammonium chloride from the wastewater and do not reduce the reaction yield. As a result of investigation on a method for producing dimethyl phosphoramidothioate, the present invention has been achieved.

[0005]

That is, the present invention provides O,
An object of the present invention is to provide a process for producing O, O-dimethylphosphoramidothioate, which comprises reacting O-dimethylphosphorochloridethioate with ammonia in the presence of an alkali hydroxide.

[0006]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, the reaction between O, O-dimethyl phosphorochloride thioate and ammonia is carried out in the presence of an alkali hydroxide. In the method of the present invention, the amount of ammonia to be used is at least 1 mole times the amount of O, O-dimethyl phosphorochloride thioate, but is not required to be as large as 2 mole times or more as in the conventional method. 1.5 mole times or less is sufficient, and usually 1.1 times.
It is in the range of .about.1.2 mol times. Such ammonia is usually used as aqueous ammonia, and the ammonia concentration at that time is arbitrary, but is generally in the range of 5 to 35% by weight, preferably 20 to 30% by weight from the viewpoint of workability and drainage.

[0007] Examples of the alkali hydroxide coexisting in this reaction include sodium hydroxide, potassium hydroxide, lithium hydroxide and the like. When the amount of the alkali hydroxide is too small, the amount of ammonia increases, so that the amount of the alkali hydroxide is usually 0.8 mol times or more, preferably 0.1 mol or more, based on O, O-dimethyl phosphorochloride thioate.
It is at least 9 mole times, and if it is too much, the reaction yield will be reduced.
It is 5 mol times or less, more preferably 1 mol time or less. Such an alkali hydroxide is usually used as an aqueous solution, and the concentration at that time is arbitrary. However, if the concentration is too low, it results in an increase in the amount of wastewater, and therefore, it is generally in the range of 5 to 50% by weight. .

[0008] The reaction method is not particularly limited, but O, O-
A method of adding aqueous ammonia and an aqueous alkali hydroxide solution to dimethyl phosphorochloride thioate is preferable, and the reaction may be performed in an atmosphere of an inert gas such as nitrogen gas. Here, the method of adding the aqueous ammonia and the aqueous alkali hydroxide solution is not particularly limited, and the required amount of the aqueous ammonia and the aqueous alkali hydroxide solution can be added all at once if there is a heat removal ability to maintain a predetermined reaction temperature. However, it is usually added continuously or intermittently.
In this case, each of the aqueous ammonia and the aqueous alkali hydroxide solution may be added alone, or a mixed solution of both may be added in advance, but the latter mixed solution is added in terms of the reaction yield. Is preferred.

When used as a mixed solution of ammonia water and an aqueous solution of alkali hydroxide, the concentration of ammonia and alkali hydroxide in the mixed solution can be adjusted so as to fall within the above-mentioned concentration range. It is.

The reaction is usually carried out by adding aqueous ammonia and an aqueous alkali hydroxide solution to O, O-dimethyl phosphorochloride thioate without using a solvent. May be used.
The solvent is not particularly limited as long as it is inert to the reaction, and examples thereof include aromatic solvents such as benzene, toluene and xylene, and halogenated hydrocarbon solvents such as methylene chloride, chloroform, dichloroethane and carbon tetrachloride. No. When such a solvent is used, the solvent is often used as a diluting solvent for O, O-dimethyl phosphorochloride thioate, and the reaction is carried out in an aqueous solution of O, O-dimethyl phosphorochloride thioate in aqueous ammonia. And an aqueous alkali hydroxide solution is added.

The reaction temperature is usually 0 to 70 ° C., preferably 2 to 70 ° C.
0-50 ° C. After the addition of aqueous ammonia and an aqueous alkali hydroxide solution into O, O-dimethyl phosphorochloride thioate, the reaction is carried out for an appropriate time, for example, 0.5 hours.
After completion of stirring for about 3 hours, the reaction is completed. Thereafter, the desired O, O-dimethylphosphoramidothioate is subjected to a post-treatment by ordinary means such as liquid separation, extraction, and solvent removal by distillation. Obtainable.

[0012]

According to the method of the present invention, the reaction does not proceed with a small amount of ammonia to produce wastewater containing a large amount of ammonium chloride, and thus wastewater treatment can be performed without the need to recover ammonium chloride from wastewater. It becomes very easy, and the target O,
O-dimethyl phosphoramidothioate can be produced.

[0013]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but it goes without saying that the present invention is not limited thereto. The purity analysis in the following examples was carried out by gas chromatography using an internal standard substance.

Example 1 250 g of O, O-dimethyl phosphor chloride thioate
(Purity: 75.7%) was heated to 40 ° C., and 91.9 g of 24% aqueous ammonia and 26.5 g were added thereto while stirring.
A mixture of 169.1 g of a 15% aqueous sodium hydroxide solution was added dropwise at the same temperature over 1 hour, and the mixture was stirred and maintained at the same temperature for 1 hour. After completion of the reaction, the reaction solution was separated into an oil layer and an aqueous layer, and the aqueous layer was subjected to extraction treatment twice with 150 g of toluene. The oil layer and the extracted toluene layer after the separation were combined, and the solvent was removed by distillation to obtain 185.1 g of O, O-dimethylphosphoramidothioate. The purity was 89.1%, and the yield was 99.0%. At this time, the concentration of NH ₄ Cl in the separated water layer (drainage) was 1.6.
%, And the NH ₄ Cl yield (production rate) was 5%.

Example 2 The reaction and post-treatment were carried out in the same manner as in Example 1 except that 206.8 g of a 30.4% aqueous solution of potassium hydroxide was used instead of 169.1 g of an aqueous solution of 26.5% sodium hydroxide. ,
184.2 g of O-dimethyl phosphoramidothioate were obtained. Purity 89.0%, yield 98.5%

Example 3 The reaction and post-treatment were carried out in the same manner as in Example 1 except that 265.7 g of a 10.1% aqueous solution of lithium hydroxide was used instead of 169.1 g of an aqueous solution of 26.5% sodium hydroxide. ,
180.7 g of O-dimethyl phosphoramidothioate were obtained. Purity 88.8%, yield 96.4%

Example 4 A reaction and post-treatment were carried out in the same manner as in Example 1 except that 186.9 g of an aqueous sodium hydroxide solution having the same concentration was used instead of 169.1 g of a 26.5% aqueous sodium hydroxide solution.
176.8 g of O-dimethyl phosphoramidothioate were obtained. Purity 88.8%, yield 94.3%

Example 5 250 g of O, O-dimethyl phosphor chloride thioate
(Purity: 75.7%) was heated to 40 ° C., and 91.9 g of 24% aqueous ammonia and 26.5 g were added thereto while stirring.
169.1 g of a 20% aqueous sodium hydroxide solution were separately added dropwise in parallel at the same temperature for 1 hour, and then stirred and maintained at the same temperature for 1 hour. After completion of the reaction, post-treatment was carried out in the same manner as in Example 1 to obtain 178.7 g of O, O-dimethylphosphoramidothioate. Purity 88.7%, yield 95.3%

Comparative Example 1 250 g of O, O-dimethyl phosphor chloride thioate
(Purity: 75.7%) was heated to 40 ° C., and 175.4 g of 24% aqueous ammonia was added thereto at the same temperature while stirring.
After dropwise addition over time, the mixture was stirred and maintained at the same temperature for 1 hour.
After completion of the reaction, post-treatment was carried out in the same manner as in Example 1, and O, O-
183.3 g of dimethyl phosphoramidothioate were obtained. Purity: 88.9%, yield: 98.3% At this time, the concentration of NH ₄ Cl in the separation water layer (drainage) is 26.
The NH ₄ Cl yield (production rate) was 100%.

Comparative Example 2 250 g of O, O-dimethyl phosphor chloride thioate
(Purity: 75.7%) was heated to 40 ° C., and 125.2 g of 24% aqueous ammonia was added thereto at the same temperature while stirring.
After dropwise addition over time, the mixture was stirred and maintained at the same temperature for 1 hour.
After completion of the reaction, post-treatment was carried out in the same manner as in Example 1, and O, O-
189.5 g of dimethyl phosphoramidothioate were obtained. Purity 63.7%, yield 72.6%

Claims (4)

[Claims] 1. A process for producing O, O-dimethylphosphoramidothioate, comprising reacting O, O-dimethylphosphorochloridethioate with ammonia in the presence of an alkali hydroxide. 2. The amount of O, O-dimethylphosphoramidothioate according to claim 1, wherein the amount of ammonia used is 1 to 1.5 times the molar amount of O, O-dimethylphosphorochloridethioate. Manufacturing method. 3. The amount of the alkali hydroxide used is 0.8 to 1. based on O, O-dimethyl phosphorochloride thioate.
The method for producing O, O-dimethylphosphoramidothioate according to claim 1, wherein the molar ratio is 1 mole. 4. The method for producing O, O-dimethyl phosphoramidothioate according to claim 1, wherein the alkali hydroxide is sodium hydroxide.