JP2985980B2 - Method for producing high-purity diarylchlorophosphate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel method for producing high-purity diarylchlorophosphate, and more particularly to a method for producing high-purity diarylchlorophosphate useful as an intermediate for pharmaceuticals, agricultural chemicals and the like.

[0002]

BACKGROUND OF THE INVENTION Hitherto, diaryl halophosphates have been
It is known as an organic phosphorus compound useful as an intermediate for pharmaceuticals and agricultural chemicals, as a raw material for resin additives, and the like. The production method is described in, for example, Japanese Patent Publication No. 2-503084.
A method for producing an alkyldiaryl halophosphate by first reacting an alkyldihalophosphite with a phenol to produce an alkyldiaryl phosphite and then halogenating the resulting alkyldiaryl phosphite is disclosed. However, this method relates to the production of an alkyldiaryl phosphite, and the alkyl dihalo phosphite as a raw material, for example, ethyl dichloro phosphite is trivalent phosphorus, so that the stability is poor and oxidation may occur. Alkyl diaryl phosphite produced in the middle of the process also has similar properties. In the next chlorination step, a solvent different from that in the previous step must be used, and a solvent having no reactivity to the halogen used, for example, carbon tetrachloride, chlorobenzene, etc., is required for industrial practice. It was not always advantageous, and improvement was required.

[0003]

SUMMARY OF THE INVENTION The present inventor has conducted research in view of such prior art, and as a result, produced an alkyldichlorophosphate by reacting an alkyl alcohol with phosphorus oxychloride. The diarylchlorophosphate can be obtained in high yield and high purity by chlorinating the alkyldiarylphosphate produced by reacting the phosphate with the phenol with phosphorus pentachloride using an onium salt as a catalyst. The inventors have found that the produced phosphorus oxychloride can be used repeatedly as a raw material, and completed the present invention.

[0004]

That is, the present invention provides a method of formula (1)

[0005]

An alkyl alcohol represented by R ¹ OH (1) (wherein R ¹ represents an alkyl group having 1 to 4 carbon atoms) is reacted with phosphorus oxychloride to form a compound represented by the formula (2)

[0006]

Embedded image The first step of producing an alkyldichlorophosphate represented by R ¹ O—P (O) Cl ₂ (2) (wherein R ¹ represents the same as described above), and then the alkyldichlorophosphate And equation (3)

[0007]

Embedded image The phenol represented by HOAr (3) (where Ar represents an aryl group) or an aqueous solution of a metal salt thereof is reacted with a phenol represented by the formula (4)

[0008]

Embedded image ^{R 1 O-P (O)} (OAr) 2 (4) ( In the formula, R ¹ represents the same meaning as defined above) a second step of producing the alkyl diaryl phosphates represented by, then the alkyl Reacting a diaryl phosphate with phosphorus pentachloride to form a compound of formula (5)

[0009]

Embedded image This is a method for producing a diarylchlorophosphate, comprising a third step of producing a diarylchlorophosphate represented by (ArO) ₂ —P (O) Cl (5).

In the method for producing a diarylchlorophosphate of the present invention, it is preferable to use an onium salt as a reaction catalyst in the third step, and to use phosphorus oxychloride by-produced in the third step in the first step. it can.

Hereinafter, the present invention will be described in detail. The method for producing a diarylchlorophosphate according to the present invention is represented by the following reaction formula.

[0012]

Embedded image First Step Formula (6) R ¹ OH + P (O) Cl ₃ → R ¹ OP (O) Cl ₂ + HCl

[0013]

Embedded image Second step formula (7) R ¹ OP (O) Cl ₂ + 2HOAr → R ¹ OP (O) (OAr) ₂ + 2HCl

[0014]

Embedded image Third step formula (8) R ¹ OP (O) (OAr) ₂ + PCl ₅ → (ArO) ₂ P (O) Cl + P (O) Cl ₃ + R ¹ Cl (wherein R ¹ is as defined above) Represent the same thing)

The first step according to the present invention relates to a method for producing an alkyl dichlorophosphate by reacting an alkyl alcohol represented by the formula (1) with phosphorus oxychloride. As the alkyl alcohol represented by the formula (1), an alkyl alcohol having 1 to 4 carbon atoms is used. For example, methanol, ethanol, 1-propanol, 2-
Examples thereof include propanol, 2-methyl-2-propanol, allyl alcohol, and ethylene oxide.

In general, the reaction may be carried out by gradually mixing phosphorus oxychloride and the above-mentioned alkyl alcohol in about equimolar amounts.
The reaction temperature is usually -10 to 10C, and particularly preferably 0C or lower. Further, a reaction solvent may be present in order to facilitate industrial operation, and it is preferable to use a solvent in which generated hydrogen halide is hardly soluble, for example, benzene, toluene, xylene and the like. . After the reaction, if a solvent is used, the solvent is distilled off.

Next, in the second step according to the present invention, the alkyldichlorophosphate, which is the reaction product of the first step, is reacted with an aqueous solution of a phenol represented by the formula (3) or a metal salt thereof to form an alkyldiaryl This is a method for producing phosphate. In this reaction, for example, when phenol is used, a dehydrochlorinating agent must be used in a solvent, but when an aqueous metal salt solution is used, it is not necessary to use a dehydrochlorinating agent.

In the reaction, the alkyldichlorophosphate obtained in the preceding step, phenols and, if necessary, a dehydrochlorinating agent are mixed in a solvent at a ratio close to the reaction equivalent shown by the formula (7) and heated, or Alternatively, the reaction is carried out by heating and stirring the aqueous solution of the alkyl dichlorophosphate and the metal salt of the phenol in a solvent such as dichloromethane. The reaction temperature is generally 0-100 ° C, preferably 10-90 ° C.

The phenol represented by the formula (3) used in this reaction is not particularly limited.
Phenol, 2-chlorophenol, 2.4-dichlorophenol, 2.5-dichlorophenol, 3.4-dichlorophenol, 2.4-5-trichlorophenol, 2.4-6-trichlorophenol, 2-bromophenol , 4-cresol and the like.

Examples of the dehydrochlorinating agent include trimethylamine, triethylamine, tripropylamine, dimethylaniline, diethylaniline, pyridine, potassium carbonate, sodium carbonate, sodium hydroxide, and the like. It is preferred to use a% aqueous sodium hydroxide solution.

When a 5 to 50% by weight aqueous sodium hydroxide solution is used as the dehydrochlorinating agent, even if the alkyldiaryl phosphate is partially or completely hydrolyzed to form a diaryl phosphate depending on the reaction temperature, there is no problem in the next step without any problem. Be transformed into

That is, a mixture of the alkyl diaryl phosphate produced in the second step and the diaryl phosphate by-produced in the second step, or the diaryl phosphate produced by hydrolyzing the alkyl diaryl phosphate produced in the second step, is In the third step, it can be chlorinated by reacting with phosphorus pentachloride. As the aqueous solution of the metal salt of a phenol represented by the formula (3) used in the reaction of the second step, an aqueous solution of an alkali metal or alkaline earth metal salt is used.

As the reaction solvent, benzene, toluene,
Examples thereof include aromatic hydrocarbons such as chlorobenzene, halogenated hydrocarbons such as tetrachloroethylene and dichloromethane, and dialkyl ketone compounds such as acetone and methyl ethyl ketone, and toluene and dichloromethane are industrially preferable. After completion of the reaction, the solvent is distilled off after washing.

Next, in the third step according to the present invention, the alkyldiaryl phosphate produced in the second step, or the mixture of the alkyldiaryl phosphate produced in the second step and the diaryl phosphate by-produced in the second step, or By a chlorination step of reacting the diaryl phosphate produced by hydrolysis of the alkyl diaryl phosphate produced in the second step with phosphorus pentachloride,
The present invention relates to a method for producing diarylchlorophosphate.

In the reaction, an alkyldiaryl phosphate and a diaryl phosphate or a mixture thereof are reacted with phosphorus pentachloride by heating without a solvent. In the present invention, the reaction rate can be increased by using an onium salt as a catalyst. Moreover, the chlorination according to the present invention cannot be performed with chlorine gas. In the chlorination according to the present invention, the diaryl phosphate by-produced or generated in the previous step can be easily chlorinated.

The onium salt is not particularly restricted but includes, for example, quaternary ammonium salts, phosphonium salts, pyridinium salts and the like. Specific examples thereof include ammonium salts such as trioctylmethylammonium chloride, tetra-n-butylammonium chloride, triethylbenzylammonium chloride, and tetraethylammonium chloride, tri-n-butylethylphosphonium bromide, tetra-n-butylphosphonium bromide, and tri-n-butylphosphonium bromide. And phosphonium salts such as -n-octylethylphosphonium bromide, and pyridinium salts such as laurylpyridinium bromide and n-ethylpyridinium bromide.

The reaction temperature is usually from 80 to 150 ° C., preferably from 100 to 120 ° C. The reaction time is usually 5-2
4 hours, preferably 10 to 16 hours. After completion of the reaction, an oily substance is obtained by cooling, and phosphorus by-product phosphorus oxychloride is recovered under reduced pressure. According to the present invention, the recovered phosphorus oxychloride can be recycled to the first step, which is mentioned as one of industrially advantageous production methods.

In order to increase the purity of the diarylchlorophosphate produced according to the present invention, unwashed onium salt and unrecovered phosphorus oxychloride which are present as impurities therein are mixed with a hydrocarbon solvent and a halogenated hydrocarbon. It can be purified with a mixed solvent of a hydrogen-based solvent. The hydrocarbon-based solvent may be any solvent that does not dissolve diarylchlorophosphate, and examples thereof include n-hexane and cyclohexane. The halogenated hydrocarbon solvent may be any solvent that dissolves diarylchlorophosphate, and examples thereof include methylene dichloride, chloroform, and tetrachloroethylene. The mixing ratio of this solvent is from 10 to 20 wt.
%, And the content of the hydrocarbon solvent is 80 to 90 wt%.

This mixed solvent is mixed at a ratio of 1 to 2 times by weight with respect to the diarylchlorophosphate and dissolved by heating. Cool at −10 ° C., crystallize and separate the solvent under N ₂ atmosphere. Drying the crystals gives a high purity diarylchlorophosphate.

[0030]

EXAMPLES The present invention will be specifically described below with reference to examples. Example 1 First step (production of O-ethyldichlorophosphate) 750 m equipped with a stirrer, a thermometer, a dropping funnel, and a condenser
43.0 g of phosphorus oxychloride in a four-necked round bottom flask
(3.15M) and cooled to 0 ° C. 138.2 g (3.00 M) of the charged ethanol was added dropwise to the dropping funnel over 90 minutes while maintaining the temperature at 0 ° C. The chlorine gas generated simultaneously with the dropping was absorbed by water. After dropping, 0 ° C
After heating for 1 hour under reduced pressure of 50 mmHg, the temperature was raised to 50 ° C., and dehydrochlorination was performed. As a result, 517.9 g of a residual liquid was obtained. As a result of analyzing this liquid by gas chromatography,
81.0 wt% of O-ethyldichlorophosphate, O,
It was a mixed solution containing 4.0 wt% of O-diethylchlorophosphate and 7.1 wt% of phosphorus oxychloride. Using an Oldershaw type rectification column, this is 70 ° C., 24 mmHg
To obtain O-ethyldichlorophosphate having a purity of 98.2% by weight.

Second step (Production of O-ethyl-O, O-bis (2,4-dichlorophenyl) phosphate) A 500 was equipped with a stirrer, a dropping funnel, a thermometer and a cooler.
In a 4-neck four-necked round-bottomed flask, 68.5 g (0.420 M) of 2,4-dichlorophenol, 100 ml of water, 99
17.0 g (0.420 M) of wt% caustic soda and 170 ml of dichloromethane were added and mixed. Next, 33.2 g of O-ethyldichlorophosphate produced in the previous step
(0.200 M) was added dropwise at 30 ° C. or lower for 1 hour. After completion of the dropwise addition, the mixture was aged at the same temperature for 1 hour, and then an organic layer and an aqueous layer were separated. The organic layer was washed with water (100 ml), dehydrated with borate, and dichloromethane was evaporated at 70 ° C., 2 mm using an evaporator.
Distillation to Hg gave 80.0 g of a colorless oil.
The colorless oil contained 10 wt% O, O-bis (2,4 dichlorophenyl) phosphate.

Third step (Production of O, O-bis (2,4 dichlorophenyl) chlorophosphate) The oil produced in the second step was placed in a 200 ml four-necked round bottom flask equipped with a stirrer, a condenser and a thermometer. 80.0g of substance
And 45.8 g (0.22 M) of phosphorus pentachloride and trioctylmethylammonium chloride (TOMAC)
Then, the temperature was raised to 100 ° C. Next, the contents were reacted at 110 ° C. for 16 hours. After completion of the reaction, the reaction mixture was cooled and recovered as a by-product phosphorus oxychloride at 70 ° C. and 35 mmHg to obtain 91.9 g of an oily substance of O, O-bis (2,4-dichlorophenyl) chlorophosphate. As a result of analysis by gas chromatography, the purity of O, O-bis (2,4-dichlorophenyl) chlorophosphate was 85.2 w.
At t%, the yield from O-ethyldichlorophosphate was 96.3%.

When the content of dichloromethane (wt%) is 13
45.0 g of the obtained O, O-bis (2,4-dichlorophenyl) chlorophosphate having a purity of 85.2 wt% was dissolved in 75 ml of a mixed solvent of dichloromethane and hexane with heating. When this was cooled to -10 ° C, crystals precipitated. This is filtered in a nitrogen atmosphere, dried and dried.
7.5 g of crystals were obtained. The purity of the crystals is 96.0 w
At t%, the recovery was 93.8%.

Example 2 First Step (Production of O-ethyldichlorophosphate) The same procedure as in Example 1 was carried out.

Second step (Production of O, O-bis (2,4-dichlorophenyl) phosphate) 500 equipped with a stirrer, a dropping funnel, a thermometer and a cooler
In a 4-neck four-necked round-bottomed flask, 68.5 g (0.420 M) of 2,4-dichlorophenol, 100 ml of water, 99
17.0 g (0.420 M) of wt% caustic soda and 170 ml of chloroform were added and mixed. Next, 33.2 g of O-ethyldichlorophosphate produced in the previous step
(0.200 M) was added dropwise at 30 ° C. or lower for 1 hour. After completion of the dropwise addition, the mixture was aged at 50 ° C. for 24 hours, and then an organic layer and an aqueous layer were separated. The organic layer was washed with 100 ml of water, dehydrated with a solution of borate, and chloroform was evaporated at 70 ° C., 2 mm with an evaporator.
Distillation to Hg gave 71.5 g of an oil. The main component of this oil was O, O-bis (2,4 dichlorophenyl) phosphate.

Third step (Production of O, O-bis (2,4 dichlorophenyl) chlorophosphate) The oil produced in the second step was placed in a 200 ml four-necked round bottom flask equipped with a stirrer, a condenser and a thermometer. 71.5g of substance
And 45.8 g (0.22 M) of phosphorus pentachloride and TOMA
As a result of adding 2.00 g of C and performing the same reaction as in Example 1, 85.6 g of an oily substance of O, O-bis (2,4-dichlorophenyl) chlorophosphate was obtained. The purity before purification was 83.1% by weight, and the yield from O-ethyldichlorophosphate was 87.6%.

Example 3 First Step (Production of O-ethyldichlorophosphate) The same procedure as in Example 1 was carried out.

The second step (O-ethyl-O, O-bis (p
Production of -chlorophenyl) phosphate 500 m with stirrer, condenser, thermometer and dropping funnel
54.0 g of p-chlorophenol in a four-necked flask
(0.420 M), water 100 ml, 99 wt% caustic soda 17.0 g (0.420 M), dichloroethane 170
ml and mixed. Next, 33.2 g (0.200 M) of O-ethyldichlorophosphate produced in the previous step.
Was dropped at 30 ° C. or lower for 1 hour, and ripening was performed for 1 hour after completion of the dropping. After separating the organic layer and the aqueous layer, the organic layer is
After washing with water and dehydrating with a bowl of nitrate, dichloromethane was distilled off with a rotary evaporator to obtain 64.3 g of a colorless and odorless oily substance.

Third step (Production of O, O-bis (p-chlorophenyl) chlorophosphate) The oily substance obtained in the second step was placed in a 200 ml four-necked flask equipped with a stirrer, a condenser and a thermometer. 3 g, phosphorus pentachloride 45.8 g (0.220 M) and TOMAC
2.00 g was added, and the reaction was carried out in the same manner as in Example 1. As a result, 75.4 g of O, O-bis (p-chlorophenyl) was added.
Chlorophosphate was obtained. The purity before purification is 86.9 w
At t%, the yield from O-ethyldichlorophosphate was 97.1%.

Example 4 In place of 2,4-dichlorophenol used in the second step of Example 1, 45.4 g of m-cresol (0.420 g) was used.
A reaction was performed in exactly the same manner as in Example 1 except that M) was used, and as a result, 66.7 g of an oily substance of O, O-bis (3-methylphenyl) chlorophosphate was obtained. The purity before purification was 80.2 wt%, and the yield from O-ethyldichlorophosphate was 90.2%.

Example 5 A reaction was carried out in exactly the same manner as in Example 1 except that 39.5 g (0.420 M) of phenol was used in place of 2,4-dichlorophenol. 58.0 g of an oily substance of diphenylchlorophosphate was obtained. The purity before purification was 88.0% by weight, and the yield from O-ethyldichlorophosphate was 95.0%.

Comparative Example 1 The reaction was carried out without adding TOMAC used in the third step of Example 1, and as a result, the yield of O, O-bis (p-chlorophenyl) chlorophosphate was 26.5%. .

[0043]

As described above, according to the production method of the present invention, an alkyl alcohol is reacted with phosphorus oxychloride to produce an alkyl dichlorophosphate, and then the alkyl dichlorophosphate is reacted with a phenol to form a product. By chlorinating the resulting alkyldiarylphosphate with phosphorus pentachloride using an onium salt as a catalyst, diarylchlorophosphate can be obtained in high yield and high purity. Further, phosphorus oxychloride by-produced in the final step can be repeatedly used as a raw material, and is an efficient and industrially advantageous method.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C07F 9/14 C07F 9/09

Claims (6)

(57) [Claims] 1. An alkyl alcohol represented by the formula (1): R ¹ OH (1) (wherein R ¹ represents an alkyl group having 1 to 4 carbon atoms) reacts with phosphorus oxychloride. To produce an alkyldichlorophosphate represented by the formula (2): R ¹ O—P (O) Cl ₂ (2) (wherein R ¹ is the same as described above) And then reacting the alkyldichlorophosphate with a phenol represented by the formula (3): HOAr (3) (where Ar represents an aryl group) or an aqueous solution of a metal salt thereof to obtain a compound represented by the formula: (4) embedded image (in the formula, R ¹ represents the same meanings as defined ^{above) R 1 O-P (O} ) (OAr) 2 (4) second step of producing an alkyl diaryl phosphates represented by, Then the alkyldiaryl phosphate is reacted with phosphorus pentachloride (5) embedded image (ArO) ₂ -P (O) Cl (5) with diaryl chlorophosphate method for producing characterized in that it consists of a third step of producing a diaryl chlorophosphate represented. 2. The method according to claim 1, wherein phosphorus oxychloride by-produced from the third step is used in the first step. 3. The method according to claim 1, wherein an onium salt is used as a catalyst in the third step. 4. The process according to claim 1, wherein the diarylchlorophosphate produced in the third step is purified with a mixed solvent of a hydrocarbon solvent and a halogenated hydrocarbon solvent. 5. A method for producing a diarylchlorophosphate represented by the formula (5) by reacting a mixture of the alkyldiarylphosphate produced in the second step and the diarylphosphate by-produced in the second step with phosphorus pentachloride. 2. The method according to claim 1, comprising three steps. 6. The method according to claim 3, wherein the alkyl diaryl phosphate produced in the second step is hydrolyzed to react with the diaryl phosphate and phosphorus pentachloride to produce the diaryl chlorophosphate represented by the formula (5). The production method according to claim 1.