JPS6347717B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing O-alkyl S-alkyl (or aryl) thiophosphoric acid chloride,
The objective is to provide a method for producing highly pure O-alkyl S-alkyl (or aryl) thiophosphoric acid chloride in good yield, which is important as an intermediate for organophosphorus pesticides. Conventionally, the following reaction is known as an example of using phosphorus oxychloride to chlorinate a pentavalent phosphoric acid ester [G.M. Kozolapov and L. Mayer, "Organophosphorus Compound"]
Volume 6, page 304 (GMKosolapoff and L.
Maier: Organic Phosphorus Compounds,
1973, Vol. 6, p. 304)]: (RO) ₃ P(O) + P(O)Cl ₃ → (RO) ₂ P(O)Cl + (RO)P(O)Cl ₂ (In the formula, R is (represents an alkyl group or an aryl group) However, this reaction proceeds somewhat when R is a lower alkyl group or a specific aryl group, but the yield is low and it is not industrially practical. Moreover, the above-mentioned document does not mention the reaction of trialkylthiophosphoric acid ester and is completely unclear. In addition, as a method for obtaining the same object as the present invention,
Method for reacting dialkyl chlorophosphite and sulfenyl chloride: (RO) ₂ PCl + R′SCl
→(RO)(R'S)P(O)Cl+RCl (in the formula, R represents an alkyl group and R' represents an aryl group) or a method of reacting S-arylthiophosphate and phosphorus pentachloride (JP-A-Sho 48―103551
No. Publication): (RO) ₂ (R′S)P(O)+PCl ₅ → (RO)(R′S)P(O)Cl+POCl ₃ +RCl (In the formula, R represents an alkyl group and R′ represents an aryl group. ) It has been known. However, the former method has a low yield of dialkyl chlorophosphite as a raw material and contains impurities such as trialkyl phosphite and alkyl dichlorophosphite, resulting in the obtained target product being of low purity. There are drawbacks. Furthermore, in the latter method, not only the raw material is limited to only S-arylthiophosphate ester, but also the reaction is intense and it is inevitable that a large amount of impurities will be produced. This is because phosphorus pentachloride abstracts oxygen atoms from S-arylthiophosphate ester.
This is probably because the once generated (RO)(R'S)P(O)Cl is further acted upon to produce R'SP(O)Cl ₂ and the like.
Additionally, phosphorus pentachloride, which is a hygroscopic and fuming solid, is difficult to handle, which poses operational problems. In view of the above drawbacks, the present inventors have proposed that O-alkyl S
-As a result of various studies on the production method of alkyl (or aryl) thiophosphoric acid chloride, we found that the target substance can be produced in extremely high yield and purity through a mild reaction by reacting thiophosphoric acid triester and phosphorus oxychloride. The present invention was completed based on the discovery that the present invention can be obtained. That is, the present invention has the general formula (RO) ₂ (R′S)P(O)
[In the formula, R represents an alkyl group having 1 to 8 carbon atoms,
R' is an alkyl group having 1 to 8 carbon atoms or

[Formula] (X represents a hydrogen atom, a halogen atom, a lower alkyl group, a cyano group, or a nitro group; General formula (RO)(R'S)P(O)Cl (in the formula, R and
This is a method for producing O-alkyl S-alkyl (or aryl) thiophosphoric acid chloride represented by (R' has the above meaning). This can be expressed as a reaction formula as follows. (RO) ₂ (R′S)P(O)+P(O)Cl ₃ →(RO)(R′S)P(O)Cl+ROP(O)Cl ₂ (In the formula, R and R′ have the above meanings. ) The general formula (RO) used here as a raw material _{is 2}
The thiophosphoric acid triester represented by (R'S)P(O) [in the formula, R and R' have the above meanings] is the reaction of alkyl (or aryl) sulfenyl chloride and trialkyl phosphite: R'SCl+
(RO) ₃ P→(RO) ₂ (R′S)P(O)+RCl [in the formula, R and R′ have the above meanings] can also be obtained, or by reaction between a dialkylthiophosphate and an alkyl halide or It can also be obtained by reacting a dialkyl phosphoric acid chloride with a thiophenol compound. In the present invention, such a thiophosphoric acid triester and phosphorus oxychloride are reacted in the presence or absence of a reaction solvent. Any reaction solvent can be used as long as it does not react with the raw materials or the desired product, such as benzene, toluene, xylene, n-pentane, n-hexane, petroleum, ether, ligroin, kerosene, dichloromethane, chloroform,
Examples include carbon tetrachloride. Note that it is possible to carry out this reaction without using a reaction solvent.
In that case, it is preferable to use a slight excess of phosphorus oxychloride relative to the thiophosphoric triester, and furthermore, the thiophosphoric triester is dissolved in phosphorus trichloride and the reaction is carried out while blowing oxygen or air into it. There is no problem. It goes without saying that the reaction ratio of phosphorus oxychloride to thiophosphoric acid triester requires a minimum stoichiometric amount, but it is usually sufficient to use 5 moles, preferably 3 moles of the latter per 1 mole of the former. If the amount is less than 1 mole, the reaction will not be achieved sufficiently, and if the amount is more than 5 moles, the number of reaction vessels will increase, and operations such as recovery and purification of excess phosphorus oxychloride will become complicated, but are not effective. The reaction temperature varies depending on the raw materials, the target product, the presence or absence of a reaction solvent, etc., but is generally room temperature to about 150°C, and 50 to 100°C is preferable in order to avoid thermal decomposition of the raw materials and target products. It is. Regarding the pressure, it does not matter whether it is reduced pressure or increased pressure. The reaction time is determined by the above conditions, but it is usually sufficient to react for 15 minutes to 20 hours, preferably 1 hour to 15 hours. According to the reaction of the present invention, it is not as violent as the reaction between S-arylthiophosphate and phosphorus pentachloride mentioned above, and there are few side reactions, and it is carried out gently and quantitatively regardless of the type of raw materials or reaction conditions. You can get what you want.
This is because the reaction between S-arylthiophosphate and phosphorus pentachloride involves a violent reaction mechanism called an oxygen atom abstraction reaction, whereas the action of phosphorus oxychloride according to the present invention is based on the reaction between the alkoxy group in the thiophosphoric acid triester and the chlorine This is because it exhibits a mild exchange reaction of atoms. Further, secondary reactions between the target product and phosphorus oxychloride are difficult to occur, and there is little room for side reactions to occur even if the reaction ratio of the raw materials is not strictly controlled. Further, while phosphorus pentachloride is a deliquescent solid that emits smoke and has a pungent odor and is difficult to handle in terms of operation, the phosphorus oxychloride of the present invention is a liquid and therefore extremely easy to handle industrially. Thus, according to the present invention, it is possible to obtain a highly purified target product in high yield through a mild reaction, and its industrial utility value is great. The present invention will be explained in more detail below with reference to Examples. Examples 1 to 8 15.61 g (equivalent to 0.1 M) of OOS-trimethylthiophosphate (CH ₃ O) ₂ P(O) SCH ₃ was placed in a four-necked flask equipped with a stirrer, a thermometer, and a reflux condenser. Phosphorus oxychloride POCl ₃ 15.33g (equivalent to 0.1M)
was added, the reaction temperature was maintained at 60° C. using an oil bath, and the reaction was carried out while monitoring the remaining amount of the raw material OOS-trimethylthiophosphate using a gas chromatograph. After about 2 hours, the raw materials completely disappeared and the reaction was completed, yielding 30.92 g of a brown reaction liquid. As a result of analyzing this reaction solution by gas chromatography internal standard method, the target product OS-dimethylthiophosphoric acid chloride (CH ₃ O) (CH ₃ S) P(O)
The Cl content was 51.0% by weight. Next, this reaction solution was separated and purified by vacuum distillation to obtain 15.23 g of a colorless and transparent liquid. bp.54~
6°C/0.4mmHg distillation yield 94.9% by weight. This was confirmed by mass spectra and elemental analysis.

[Table] Corresponding O-alkyl S-alkyl (or aryl) thiophosphoric acid chlorides were produced using various thiophosphoric triesters by the same method, and the results shown in Table 1 were obtained.

【table】

[Table] * Upper row: Theoretical values Lower row: Actual measured values Examples 9 to 11 O, O, and S were added to the same four-necked flask as in Example 1.
-Take 45.07g (equivalent to _0.1M ) of trioctylthiophosphate _{(C8H17O)2P(O)SC8H17 , add 30.66g} (equivalent to 0.20M) of phosphorus oxychloride, and react in an oil bath. While keeping the temperature at 80℃, the raw materials O, O, S-
The reaction was carried out while monitoring the remaining amount of trioctylthiophosphate. After 14 hours, the raw materials completely disappeared and 75.60 g of reaction liquid was obtained. As a result of analyzing this reaction solution by gas chromatography internal standard method, the content of the target product O,S- _{dioctylthiophosphoric} acid chloride ( _C8H17O )( _C8H17S )P(O ₎ Cl was found to be
The yield was 93.2% by weight. Excess phosphorus oxychloride and by-product (C ₈ H ₁₇ O)P(O)Cl ₂ are recovered from this reaction solution under reduced pressure, and the residue is
34.27g was obtained. This was confirmed by mass spectra and elemental analysis.

[Table] Corresponding O-alkyl S-arylthiophosphoric acid chlorides were produced by changing the thiophosphoric acid triester by the same method, and the results shown in Table 2 were obtained. Example 12 21.22 g of O,O-diethyl-Sn-propylthiophosphate, 40 c.c. of toluene, and 16.86 g of phosphorus oxychloride were added to a four-necked flask equipped with a stirrer, thermometer, and reflux condenser. The reaction temperature was maintained at 80°C using an oil bath and the mixture was stirred. The reaction was completed after 15 hours, and 71.82 g of a light brown reaction liquid was obtained. Analysis of this reaction solution by gas chromatography internal standard method revealed that the content of the target product, O-ethyl-Sn-propylthiophosphoric acid chloride, was 28.0% by weight, and the yield was 99.2% by weight. A colorless transparent liquid is obtained from this reaction solution by vacuum distillation.
Obtained 19.40g. Distillation yield 95.7% by weight.

[Table] Comparative example 21.22 g (0.1 mol) of O,O-diethyl-Sn-propylthiophosphate and 60 c.c. of carbon tetrachloride were added to a four-necked flask equipped with a stirrer, thermometer, and condenser. Dissolve. Weigh 20.82g of phosphorus pentachloride into an Erlenmeyer flask,
Seal tightly. Add a small amount of this to the reaction flask using a spatula. After the addition was complete, stir at room temperature for 1 hour, and then stir for another 50 minutes.
Incubate at ℃ for 2 hours. Carbon tetrachloride and phosphorus oxychloride are removed from the reaction solution by distillation. When this product was analyzed by gas chromatography, impurities were found to be n-propyl-disulfide, S-n-propylthiophosphoric acid dichloride, and the raw material O,O-diethyl-S-
The purity of the target product, O-ethyl-Sn-propylthiophosphoric acid chloride, was 62.2% by weight, including n-propylthiophosphoric acid ester and several other peaks of impurities.

【table】

[Table] * Upper row: Theoretical value Lower row: Actual value

Claims (1)

[Claims] 1 General formula, (RO) ₂ (R'S)P(O) [In the formula, R represents an alkyl group having 1 to 8 carbon atoms, and R' has 1 carbon number.
~8 alkyl group or a phenyl group represented by the formula General formula (RO) (R′S) characterized by reacting thiophosphoric acid triester and phosphorus oxychloride
P(O)Cl (in the formula, R and R' have the above meanings)
A method for producing O-alkyl S-alkyl (or aryl) thiophosphoric acid chloride represented by