JP3409590B2 - Process for producing O, O-dimethylphosphoramidothioate - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing O, O-dimethylphosphoroamidothioate.

[0002]

BACKGROUND OF THE INVENTION O, O-dimethyl phosphoroamidothioate is well known as a production intermediate of O, S-dimethyl N-acetylphosphoroamidothioate useful as an insecticide, and its production method is known. Also, a method of reacting O, O-dimethyl phosphorochloridothioate with ammonia is well known. (East German Patent No. 16106
No. 9)

However, this method not only requires a large amount of ammonia, which is more than 2 mol times as much as O, O-dimethylphosphorochloride thioate, but also produces waste water containing a large amount of by-produced ammonium chloride. Therefore, the processing has become a big problem. Further, in order to effectively use ammonia, an ammonia recovery process for recovering ammonia from such ammonium chloride-containing wastewater is required, but in that case, there is a problem that equipment cost becomes very high. When used as a raw material, there is also a problem that the yield of O, O-dimethylphosphoroamidothioate decreases due to impurities in the recovered ammonia.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The inventors of the present invention have solved such a problem, and do not generate wastewater containing a large amount of ammonium chloride, and therefore, it is not necessary to recover ammonium chloride from the wastewater, and the reaction yield does not decrease. As a result of examination on a method for producing dimethylphosphoroamidothioate, the present invention has been completed.

[0005]

That is, the present invention provides O,
The present invention provides a method for producing O, O-dimethylphosphoroamidothioate, which comprises reacting O-dimethylphosphorochloride thioate with ammonia in the presence of an alkali hydroxide.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the reaction of O, O-dimethylphosphorochloride thioate and ammonia is carried out in the presence of alkali hydroxide. In the method of the present invention, the amount of ammonia used is required to be 1 mol times or more with respect to O, O-dimethylphosphorochloride thioate, but not as large as 2 mol times or more as in the conventional method, 1.5 mol times or less is sufficient and usually 1.1
The range is up to 1.2 times. Such ammonia is usually used as aqueous ammonia, and the concentration of ammonia at that time is arbitrary, but it is generally in the range of 5 to 35% by weight, preferably 20 to 30% by weight from the viewpoint of workability and the amount of discharged water.

Examples of the alkali hydroxide to be coexistent in this reaction include sodium hydroxide, potassium hydroxide, lithium hydroxide and the like. If the amount of the alkali hydroxide used is too small, the amount of the ammonia used increases. Therefore, the amount of the alkali hydroxide used is usually 0.8 mol times or more, preferably 0. 0 times the O, O-dimethylphosphorochloride thioate.
9 mol times or more, and if it is too much, the reaction yield decreases, so 1.1 mol times or less, preferably 1.0 mol times or less.
It is 5 times or less, more preferably 1 times or less. Such an alkali hydroxide is usually used as an aqueous solution, and the concentration at that time is arbitrary, but if the concentration is too low, it also leads to an increase in the amount of drainage, so it is generally in the range of 5 to 50% by weight. .

The reaction method is not particularly limited, but O, O-
A method of adding aqueous ammonia and an aqueous alkali hydroxide solution to dimethylphosphorochloride thioate is preferable, and the reaction may be carried out in an atmosphere of an inert gas such as nitrogen gas. Here, the method of adding the ammonia water and the aqueous alkali hydroxide solution is not particularly limited, and if the heat removal capacity for maintaining the predetermined reaction temperature is available, all the required amount of the aqueous ammonia and the aqueous alkali hydroxide solution are added all at once. Although it may be added, it is usually added continuously or intermittently.
In this case, the ammonia water and the alkali hydroxide aqueous solution may be added individually to each, or a mixed solution prepared by mixing the two may be added in advance, but the latter mixed solution is added in terms of reaction yield. Is preferred.

When used as a mixed solution of ammonia water and an aqueous solution of alkali hydroxide, the concentrations of ammonia and alkali hydroxide in the mixed solution can be adjusted so as to fall within the concentration ranges described above. Is.

The reaction is usually carried out by adding ammonia water and an aqueous alkali hydroxide solution to O, O-dimethylphosphorochloride thioate without using a solvent, but if necessary, a solvent may be added. 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, halogenated hydrocarbon solvents such as methylene chloride, chloroform, dichloroethane and carbon tetrachloride. Can be mentioned. When such a solvent is used, it is often used as a diluting solvent for O, O-dimethylphosphorochloride thioate, and the reaction is carried out in a solution of O, O-dimethylphosphorochloride thioate in aqueous ammonia. And a method of adding an alkali hydroxide aqueous solution.

The reaction temperature is usually 0 to 70 ° C., preferably 2
It is 0 to 50 ° C. The reaction is carried out by adding aqueous ammonia and an aqueous alkali hydroxide solution into O, O-dimethylphosphorochloride thioate, and then adding a suitable time such as 0.5.
The stirring is continued for about 3 hours to complete the reaction, and after that, the target O, O-dimethylphosphoroamidothioate is subjected to post-treatment by usual means such as separation, extraction, and removal of the solvent by distillation. Obtainable.

[0012]

EFFECTS OF THE INVENTION According to the method of the present invention, it is possible to perform wastewater treatment without causing the reaction to proceed with a small amount of ammonia and producing wastewater containing a large amount of ammonium chloride, and thus without the need to recover ammonium chloride from the wastewater. It is very easy to achieve the desired O, without decreasing the reaction yield.
O-dimethyl phosphoroamido thioate can be prepared.

[0013]

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 performed by gas chromatography using an internal standard substance.

Example 1 250 g of O, O-dimethylphosphoryl chloride thioate
(Purity: 75.7%) was heated to 40 ° C., and while stirring, 24% aqueous ammonia 91.9 g and 26.5 were added thereto.
A mixture of 169.1 g of an aqueous solution of sodium hydroxide at 16% was added dropwise at the same temperature over 1 hour, and then the mixture was stirred and held at the same temperature for 1 hour. After the reaction was completed, the reaction solution was separated into an oil layer and an aqueous layer, and the aqueous layer was extracted twice with 150 g of toluene. The separated oil layer and extracted toluene layer were separated, and the solvent was removed by distillation to obtain 185.1 g of O, O-dimethylphosphoroamidothioate. Purity 89.1%, Yield 99.0% At this time, the concentration of NH ₄ Cl in the liquid separation layer (drainage) was 1.6.
%, And the NH ₄ Cl yield (production rate) was 5%.

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

Example 3 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 lithium hydroxide solution was used instead of 169.1 g of a 26.5% aqueous sodium hydroxide solution. ，
180.7 g of O-dimethyl phosphoroamido thioate was obtained. Purity 88.8%, Yield 96.4%

Example 4 The same reaction and post-treatment were carried out 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 phosphoroamido thioate was obtained. Purity 88.8%, Yield 94.3%

Example 5 250 g of O, O-dimethylphosphoryl chloride thioate
(Purity: 75.7%) was heated to 40 ° C., and while stirring, 24% aqueous ammonia 91.9 g and 26.5 were added thereto.
% Aqueous sodium hydroxide solution (169.1 g) was separately added in parallel at the same temperature over 1 hour, and then the mixture was stirred and held 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 O, O-dimethylphosphoroamidothioate (178.7 g). Purity 88.7%, yield 95.3%

Comparative Example 1 O, O-dimethylphosphoryl chloride thioate 250 g
(Purity: 75.7%) was heated to 40 ° C., and 175.4 g of 24% ammonia water was added to the mixture at a temperature of 1 while stirring.
After dropping over a period of time, the mixture was stirred and maintained at the same temperature for 1 hour.
After completion of the reaction, post-treatment is carried out in the same manner as in Example 1, and O, O-
183.3 g of dimethyl phosphoroamido thioate was obtained. Purity 88.9%, Yield 98.3% At this time, the concentration of NH ₄ Cl in the liquid separation layer (drainage) was 26.
8%, and the NH ₄ Cl yield (production rate) was 100%.

Comparative Example 2 250 g of O, O-dimethylphosphoryl chloride thioate
(Purity: 75.7%) is heated to 40 ° C., and while stirring, 125.2 g of 24% ammonia water is added at the same temperature to 15.2 g.
After dropping over a period of time, the mixture was stirred and maintained at the same temperature for 1 hour.
After completion of the reaction, post-treatment is carried out in the same manner as in Example 1, and O, O-
189.5 g of dimethyl phosphoroamido thioate was obtained. Purity 63.7%, Yield 72.6%

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Claims (4)

(57) [Claims] 1. A process for producing O, O-dimethylphosphoroamidothioate, which comprises reacting O, O-dimethylphosphorochloride thioate with ammonia in the presence of an alkali hydroxide. 2. The O, O-dimethylphosphoroamidothioate according to claim 1, wherein the amount of ammonia used is 1 to 1.5 mol times that of O, O-dimethylphosphorochloride thioate. Manufacturing method. 3. The amount of alkali hydroxide used is 0.8-1.O.m with respect to O, O-dimethylphosphorochloride thioate.
The method for producing O, O-dimethylphosphoroamidothioate according to claim 1, wherein the amount is 1 mol times. 4. The method for producing O, O-dimethylphosphoroamidothioate according to claim 1, wherein the alkali hydroxide is sodium hydroxide.