JPH0138795B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing dihalogenodithiophosphoric acid ester, and its purpose is to easily and economically produce highly pure dihalogenodithiophosphoric acid ester in a good yield, that is, industrially. The object of the present invention is to provide a method for manufacturing the same.

Dihalogenodithiophosphates themselves are known compounds, and they are useful as intermediates for the production of organophosphorus pesticides, particularly insecticides, fungicides, and herbicides.

Conventional methods for producing dihalogenodithiophosphate esters include (a) combining a thiol compound and thiophosphoryl halide with metal, anhydrous metal halide, Lewis acid,
A method for producing in the presence of a specific catalyst such as lactam, carboxylic acid amide or phosphoric acid amide
-12132), (b) a method of sulfurizing starting from mercaptan and phosphorus trihalide in the presence of a sulfurization catalyst (JP-A-52-51322); Or a method of sulfiding with phosphonic acid dithioanhydride (JP-A-49-
86347), etc. are known. However, method (a) requires a long reaction time and a low yield, and method (b) requires a long process and requires analysis and measurement of the reaction solution during the reaction, making the operation complicated. Regarding method (c), the yield is low and the treatment of the reaction residue of the sulfurizing agent, phosphorus pentasulfide or phosphonic acid dithioanhydride, is not easy due to odor, by-products, handling, etc. This method has its advantages and disadvantages, and the current situation is that it is not satisfactory.

In view of the above, the present inventors have conducted various studies on the production method of dihalogenodithiophosphoric acid ester, and have found that a mixed catalyst of phosphorus trihalide and anhydrous aluminum chloride is effective in reacting a thiol compound with a thiophosphoryl halide. They discovered this and completed the present invention. That is, the present invention relates to a thiol compound represented by the formula RSH (wherein R represents a _C1-5 alkyl group, phenyl group or substituted phenyl group) and a formula PSX ₃ (wherein X represents chlorine, bromine, iodine or fluorine). A formula characterized by the presence of phosphorus trihalide of the formula PX ₃ (wherein X has the above meaning) and anhydrous aluminum chloride as a catalyst in reacting a thiophosphoryl halide represented by
This is a method for producing a dihalogenodithiophosphoric acid ester of RSP(S)X ₂ (in the formula, R and X each have the above meanings).

All of the raw materials used in the present invention are common and can be easily obtained or produced, and it is natural that they are preferably as pure as possible. The thiol compound has the formula RSH, where R is a _C1-5 alkyl group, phenyl group, or substituted phenyl group. Specifically, methyl, ethyl, n-propyl,
Alkyl groups such as isopropyl, n-butyl, isobutyl, secondary butyl, tertiary butyl, n-pentyl, isopentyl, secondary pentyl, neopentyl, and nitro, chloro, methyl, trifluoromethyl, methoxy, methylthio, etc. 1-3
Mention may be made of phenyl groups substituted with .

Examples of the thiophosphoryl halide include phosphorus thiochloride, phosphorus thiobromide, phosphorus thioiodide, and phosphorus thiofluoride, with phosphorus thiochloride being particularly common.

The catalyst phosphorus trihalide is phosphorus trichloride,
There are phosphorus tribromide, phosphorus triiodide, phosphorus trifluoride, etc., of which phosphorus trichloride is the most common. Moreover, as aluminum chloride, anhydrous aluminum chloride is preferable.

In the present invention, the reaction is carried out using the above-mentioned raw materials, and to explain its implementation mode, a thiol compound is added to thiophosphoryl halide in the presence of phosphorus trihalide and anhydrous aluminum chloride, and the reaction is carried out for a certain period of time. The reaction is completed by heating and aging at a predetermined temperature. This can be expressed as a formula as follows.

RSH + _{PSX 3} PX ₃ , AlCl ₃ ――――――――→ RSP (S) The thiophosphoryl halide may be added to the thiol compound, or both raw materials may be added dropwise at a constant rate at the same time. In the case of a thiol compound, it is preferable to add the thiol compound to the thiophosphoryl halide as described above.

In formula (1), the reaction solvent is not necessarily an essential requirement, and when used, an inert organic solvent such as benzene, toluene, xylene,
Chlorbenzene, ligroin, kerosene, etc. are used.

As can be understood from equation (1), the reaction amount of the raw material thiol compound and thiophosphoryl halide is theoretically 1 mole of the former for every 1 mole of the latter, but in reality it is 1 mole for every 1 mole of the former. Latter 1~
It requires 10 times the mole, preferably 1 to 5 times the mole. If less than 1 times the mole, the reaction will not be sufficient, and if more than 10 times the mole is used, the reaction capacity and operating energy will be reduced.
This is because it is not a good idea in consideration of recycling and use.

The amounts of phosphorus trihalide and anhydrous aluminum chloride as catalysts to be present are preferably about 0.005 to 0.2 mole each per mole of thiol compound. This is because if it is used in an extremely small amount, it will not have a catalytic effect, and if it is used in a large amount, it will produce by-products, which is undesirable.

The method of the present invention is carried out at -20 to 200°C, preferably from 0 to 200°C.
It is generally carried out at temperatures between 160°C and under normal pressure. However, the reaction may be carried out under pressure or reduced pressure. Regarding the reaction atmosphere, in order to prevent undesirable oxidation reactions, it is recommended to carry out the reaction under an atmosphere of an inert gas, such as nitrogen gas.

Although the reaction time varies depending on the raw materials, catalyst, temperature, reaction scale, etc., it is about 1 to 10 hours, and in any case, the reaction can be carried out in a much shorter time than conventional methods.

3RSH＋PSX ₃ PX ₃ ,AlCl ₃ ――――――――→ (RS) ₃ PS＋3HX ………(2) (RS) ₃ PS＋2PSX ₃ PX ₃ ,AlCl ₃ ――――――――→ 3RSP(S ₎ It is thought that RS) ₃ PS is generated, which then reacts with thiophosphoryl halide as shown in formula (3) to reach dihalogenodithiophosphoric acid ester.

Therefore, when carrying out the present invention, the reaction may be carried out in a one-step process as in equation (1), or in a two-step process as in equations (2) and (3). The two-step process is particularly suitable when it is necessary to isolate the tetrathiophosphate (RS) ₃ PS or when it is easily available from other sources. When using the two-stage method
The dehydrohalogenation reaction in equation (2) is carried out at a low temperature range of -20 to 100℃, and the heat aging reaction in equation (3) is carried out at a temperature of 100 to 200℃.
It is preferable to carry out the reaction in a high temperature range of °C. Further, the effect of the catalysts phosphorus trihalide and anhydrous aluminum chloride is particularly remarkable in formula (2), and in formula (3), phosphorus trihalide can be omitted depending on the case. However, usually following equation (2),
Since equation (3) is carried out in the same reaction vessel, it is common to use a common catalyst. The reaction amount of the raw material in the two-stage method is not necessarily limited to the theoretical amount as expressed by formulas (2) and (3), and may be appropriately selected within the range of the reaction amount of the raw material described above. This also applies to the amount of catalyst.

Regardless of whether a one-step method or a two-step method is adopted, after the reaction according to the present invention is completed, the excess thiophosphoryl halide and the solvent, if used, are distilled off according to a conventional method. The purified target product is obtained by distillation under reduced pressure or recrystallization if necessary. The distillation residue obtained at this time can be recycled together with phosphorus trihalide and anhydrous aluminum chloride as a catalyst for the reaction of a thiol compound and thiophosphoryl halide.

Thus, according to the present invention, high-purity dihalogenodithiophosphoric acid ester can be produced easily and economically, that is, industrially, in good yield due to the synergistic effect of phosphorus trihalide and anhydrous aluminum chloride.

The present invention will be specifically described below with reference to Examples and Comparative Examples.

Example 1 In a 500 c.c. four-neck flask equipped with a stirrer, thermometer, dropping funnel, and condenser, 169.4 g (1 mol) of phosphorus thiochloride (thiophosphoryl chloride) and 4.1 g (0.03 mol) of phosphorus trichloride were added. ) and 2.7 g (0.02 mol) of anhydrous aluminum chloride were added and heated to 70°C, and 228.5 g (3 mol) of n-propyl mercaptan was added thereto via a dropping funnel over 2 hours. Thereafter, stirring was continued for 30 minutes to complete the reaction. 280.4 g (yield 97.2%) of tri-n-propyl tetrathiophosphate was obtained from the reaction solution by distillation under reduced pressure (b0.06 105-8°C). The purity of this product was 98.4% by gas chromatography relative area method.

Next, 96.2 g of tetrathiophosphoric acid tri-n-propyl ester was added to the same 500 c.c. four-necked flask as above.
(1/3 mole), 451.7 g (2 2/3) of phosphorus thiochloride and 3.3 g (0.025 mole) of anhydrous aluminum chloride were added.
Heat at 130-135°C for 3 hours. Excess phosphorus thiochloride was removed from the reaction solution by distillation, and then dichloridodithiophosphoric acid-n-propyl ester was distilled under reduced pressure (b ₃ 90-95°C). As a result, the yield was 185.6g (yield
88.8%), and the purity was 97.6% as determined by gas chromatography internal standard method.

Example 2 508.2 g of phosphorus thiochloride was placed in a 500 c.c. four-necked flask equipped with a stirrer, thermometer, dropping funnel, and condenser.
(3 mol), 6.9 g (0.05 mol) of phosphorus trichloride and 5.4 g (0.04 mol) of anhydrous aluminum chloride,
It was heated to 60℃. 76.2g (1 mol) from the dropping funnel
of n-propyl mercaptan was added over 30 minutes. Thereafter, the temperature was rapidly increased to 130°C to 135°C for 2 hours. After removing excess phosphorus thiochloride from the reaction solution, 181.9 g (yield: 87.0%) of dichloride dithiophosphoric acid-n-propyl ester was obtained by distillation under reduced pressure. The purity of this product was 96.9%.

Example 3 508.2 g of phosphorus thiochloride was added to the residue from the distillation pot of Example 2.
(3 moles), 6.9 g (0.05 moles) of phosphorus trichloride, and 4.0 g (0.03 moles) of anhydrous aluminum chloride,
It was heated to 60℃. 76.2g (1 mol) from the dropping funnel
of n-propyl mercaptan was added over 30 minutes, rapidly heated to reflux temperature, and reacted for 1 hour. After removing excess phosphorus thiochloride from the reaction solution, dichloride thiophosphoric acid-n-propyl ester was obtained by distillation under reduced pressure.
197.2g (yield 94.3%) was obtained. The purity of this product was 95.9%.

Example 4 In Example 2, the amount of phosphorus thiochloride was changed to 254.1 g.
(1.5 mol) and the others were reacted under the same conditions. After removing excess phosphorus thiochloride from the reaction solution, 180.2 g (yield: 86.2%) of dichloride dithiophosphoric acid-n-propyl ester was obtained by distillation under reduced pressure. The purity of this product was 96.3%.

Example 5 In the second half of the reaction of Example 1, the amount of anhydrous aluminum chloride was 1.3 g (0.01 mol) and the other conditions were the same. After refluxing for 10 hours, the reaction was stopped, excess phosphorus thiochloride was distilled off, and 172.5 g (yield: 82.5%) of dichloride thiophosphoric acid n-probyl ester was obtained by distillation under reduced pressure. The purity of this product was 95.2%.

Comparative Example 1 When anhydrous aluminum chloride is not used in Example 1 In a 500 c.c. four-necked flask equipped with a stirrer, thermometer, dropping float, and condenser, 169.4 liters of phosphorus thiochloride was added.
g (1 mol) and phosphorus trichloride 6.9 g (0.05 mol)
was added and heated to 70°C. 228.5 from dripping float
g (3 mol) of n-propyl mercaptan were added in 2 hours. Due to the reflux of the mercaptan, it took time to raise the temperature to 120°C, which took 2 hours and 30 minutes. After cooling,
As a result of washing twice with a 5% NaOH aqueous solution and distilling under reduced pressure, 261.4 g (yield 90.6%) of tetrathiophosphoric acid n-propyl ester (b _0.05 100-107°C) was obtained.
The purity of this product was 88.9% by gas chromatography relative area method.

Take 96.2 g (1/3 mol) of this tetrathiophosphoric acid tri-n-propyl ester, and
451.7g2 (2 2/3 mol) and heated at 130-135℃.
React for 10 hours. Excess phosphorus thiochloride was distilled off from the reaction solution, and then 44.3g (yield
21.2%) of dichloride thiophosphoric acid-n-propyl ester was obtained. The purity of this product was found to be 83.6% by gas chromatography internal standard method.

As seen in this example, when anhydrous aluminum chloride is not used, the results of the first half of the reaction are not good, but the second half of the reaction does not proceed particularly well and only dichloride thiophosphoric acid ester is obtained in low yield and low purity.

Comparative Example 2 When phosphorus trichloride is not used in Example 1 3.3 g (0.025 mol) of anhydrous aluminum chloride is added to 169.4 g (1 mol) of phosphorus thiochloride and heated to 70°C. 228.5 g (3 mol) of n-propyl mercaptan was added from a dropping float over 2 hours. The temperature was gradually increased to 120°C after 3 hours. During this time, the mercaptan was refluxing rapidly. Distill the reaction solution under reduced pressure to obtain 227.6g (yield 78.9%)
Tetrathiophosphoric acid tri-n-propyl ester was obtained. The purity of this product was 86.3%.

To 96.2 g (1/3 mol) of this tetrathiophosphoric acid tri-n-propyl ester, 451.7 g of phosphorus thiochloride2
(2 2/3 mol) and 3.3 g of anhydrous aluminum chloride
(0.025 mol) was added and heated at 130-135°C for 3 hours. Excess phosphorus thiochloride was distilled off from the reaction solution, and then 170.8 g (yield: 81.7%) of dichloride thiophosphoric acid n-propyl ester was obtained by distillation under reduced pressure. The purity of this product was 94.2%.

As seen in this example, the effect of phosphorus trichloride is particularly significant in the first half of the reaction, and tetrathiophosphate is obtained in low yield and purity. This influence also appears in the latter half of the reaction, reducing the yield and purity of dichloride thiophosphoric acid ester.

Comparative Example 3 When dimethylformamide (DMF) and iodine were used as a catalyst. Instead of using anhydrous aluminum chloride and phosphorus trichloride in Example 2, 0.9 g of dry N,N-dimethylformamide and 0.5 g of iodine were used, and other conditions were used. I tried to do everything the same way. When the temperature was slightly raised after the dropwise addition of n-propyl mercaptan, reflux of the mercaptan occurred violently, and it took 2 hours and 10 minutes to raise the temperature to 130°C. After reacting for 6 hours at reflux temperature, excess phosphorus thiochloride was distilled off, and dichloride thiophosphoric acid-n-propyl ester was obtained by distillation under reduced pressure.
146.3g (yield 70.0%) was obtained. The purity of this product was 91.1%.

Claims (1)

[Scope of Claims] 1 A thiol compound represented by the formula RSH (wherein R represents a C _1-5 alkyl group, phenyl group or substituted phenyl group) and a thiol compound represented by the formula PSX ₃ (wherein X is chlorine, bromine, In reacting thiophosphoryl halide represented by iodine or fluorine), phosphorus trihalide of the formula PX ₃ (wherein X has the above meaning) and anhydrous aluminum chloride are present as catalysts. A method for producing a dihalogenodithiophosphoric acid ester represented by the formula RSP(S)X ₂ (wherein R and X each have the above meanings). 2. The method for producing a dihalogenodithiophosphate ester according to claim 1, wherein 1 mole of a thiol compound is reacted with 1 to 10 times the mole of thiophosphoryl halide. 3. The method for producing a dihalogenodithiophosphate ester according to claim 1 or 2, which comprises reacting a thiol compound and thiophosphoryl halide at a temperature range of -20 to 200°C. 4. The method according to claims 1 to 3, in which a thiol compound and a thiophosphoryl halide are first reacted in a temperature range of -20 to 100°C to dehydrohalogenate, and then heated and aged in a temperature range of 100 to 200°C. A method for producing a dihalogenodithiophosphoric acid ester according to any one of the above. 5. The method for producing a dihalogenodithiophosphoric acid ester according to any one of claims 1 to 4, wherein 0.005 to 0.2 moles of phosphorus trihalide and anhydrous aluminum chloride are present per mole of the thiol compound. 6. Production of dihalogenodithiophosphoric acid ester according to any one of claims 1 to 5, wherein the distillation residue after distilling off the dihalogenodithiophosphoric acid ester and/or thiophosphoryl halide is recycled together with a catalyst. Method.