JP3014231B2 - Method for producing organic phosphorus compound - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a novel flame retardant containing elemental phosphorus.

[0002]

2. Description of the Related Art M. J. Rauhut et al. Am. C
hem. Soc. 81, 1103 pages (1959)
Year) describes a method for producing this compound. However, according to the literature method, a neutralization treatment is performed after completion of the reaction to obtain the desired product. However, in fact, only neutralizing the reaction solution does not protonate all the carboxyl anions of the desired product, and the desired product is mono- It remains in the reaction solution in the form of a metal salt. Thereafter, when the solvent is concentrated, a yellow oily substance is produced, or a mixture of the yellow oily substance and white crystals is produced, and the target substance can be isolated purely unless solvent extraction is repeated or complicated operations such as column chromatography are performed. Can not do it.

[0003] As described above, in the conventional method, the operation of obtaining the desired product is complicated and complicated, and there is no reproducibility of the reaction.
There is a need for further improvements in industrially producing this compound.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to improve the disadvantages of the prior art and to provide a flame retardant which is effective, harmless and has excellent flame retardancy in a small amount in a simple and industrial manner. It is an object of the present invention to provide a low-cost manufacturing method.

That is, the method of the present invention comprises the following steps: 1) reacting a phosphine with a vinyl compound having a cyano group or a functional group convertible to the cyano group;

Wherein X represents an alkyl group, an aryl group, an aralkyl group, a saturated alicyclic compound, and Y represents a hydrogen atom or a methyl group. 2) 1 The oxidizing agent is reacted with the compound obtained in

Wherein L represents an alkyl group, an aryl group, an aralkyl group, a saturated alicyclic compound, and M represents a hydrogen atom or a methyl group. 3) 2 ) Is reacted with a base, and after the reaction is completed, the reaction solution is acidified.

Wherein R is an alkyl group, an aryl group, an aralkyl group, a saturated alicyclic compound, R ′ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ″ is a hydrogen atom or methyl. Represents a group.).

The alkyl group referred to in the present invention has the general formula C _n
Examples include methyl, ethyl, propyl, butyl or isomers thereof represented by H _{2n + 1} . The aryl group referred to in the present invention is C ₆ H ₅ , C ₆ H ₄ —CH ₃ , C ₆ H
_3- (CH ₃ ) ₂ , C ₆ H ₄ — (CH ₂ CH ₃ ) and the like, and the aralkyl group includes C ₆ H ₅ —CH ₂ ,
_{6 H 4 (CH 3) -CH} 2, C 6 H 5 -CH 2 CH 2,
C ₆ H ₃ (CH ₃ ) ₂ —CH _{2 and the} like are mentioned, and the saturated alicyclic compound is, for example, a cyclohexyl group represented by C _n H _2n-1 . Or the substituent E is ant
An aromatic phosphine such as phenylphosphine, benzylphosphine, methylphenylphosphine, ethylphenylphosphine, propylphenylphosphine, dimethylphenylphosphine, or an isomer thereof; Or dichlorophenylphosphine, dichlorobenzylphosphine, dichloromethylphenylphosphine, dichloroethylphenylphosphine, dichloropropylphenylphosphine, dichlorodimethylphenylphosphine, or an isomer thereof, in which the substituent F is a chlorine atom. Or general formula

Wherein X represents an alkyl group, an aryl group, an aralkyl group, a saturated alicyclic compound, and Y represents a hydrogen atom or a methyl group. Wherein the substituent F is a hydrogen atom, for example, methylphosphine, ethylphosphine, propylphosphine, butylphosphine or isomers thereof, or dichloromethylphosphine, dichloroethylphosphine, dichloropropylphosphine wherein the substituent F is a chlorine atom And phosphines such as saturated alicyclic phosphines such as dichlorocyclohexylphosphine and cyclohexylphosphine, and aliphatic phosphines such as dichlorobutylphosphine and isomers thereof. Among them, the boiling point, melting point,
Aromatic phosphines or saturated alicyclic phosphines are preferred because they have good physical and chemical properties such as solubility and heat resistance, and are easy to handle, easy to carry out after-treatment, or obtain the desired product in high yield. Its use is most favorable. The phosphines used in the present invention are not limited to those exemplified here.

[0007] The vinyl compound used in the method of the present invention includes acrylonitrile or vinyl chloride, vinyl bromide or other derivatives thereof which can be converted to these compounds by a suitable chemical reaction. When vinyl chloride, vinyl bromide or the like is used, an appropriate cyanating agent such as sodium cyanide is added after the addition reaction.
A cyano group may be introduced by a substitution reaction with potassium cyanide or the like.

According to the method of the present invention, the general formula

Wherein X represents an alkyl group, an aryl group, an aralkyl group, a saturated alicyclic compound, and Y represents a hydrogen atom or a methyl group. And two or more equivalents of a vinyl compound with benzene, toluene,
It can be obtained by reacting with phosphines in an inert solvent such as xylene, tetrahydrofuran, dioxane, dichloromethane, chloroform or the like or a vinyl compound described above as a solvent at an appropriate temperature of 20-50 ° C for 1-5 hours.

According to the method of the present invention, if necessary, a reaction such as sodium hydroxide, potassium hydroxide or the like can coexist to allow the reaction to proceed more smoothly.
If an inert gas such as nitrogen, argon, or helium is continuously introduced, the yield of the desired product can be reduced.
Can be obtained.

According to the method of the present invention, the method obtained by the above method is provided.

Wherein X represents an alkyl group, an aryl group, an aralkyl group, a saturated alicyclic compound, and Y represents a hydrogen atom or a methyl group; a hydrogen peroxide solution; 1-2 equivalents of a normal oxidizing agent such as mercury compound, mercury oxide, mercuric chloride, oxygen, ozone, organic peroxide, organic peracid, nitrous oxide, dimethyl sulfoxide, at 30-110 ° C.
At a suitable temperature of 1.5 to 3 hours to obtain a compound of the general formula

Wherein L represents an alkyl group, an aryl group, an aralkyl group, a saturated alicyclic compound, and M represents a hydrogen atom or a methyl group. Among them,
Hydrogen peroxide solution, oxygen, organic peroxides, organic peracids, dinitrogen tetroxide, dimethyl sulfoxide in terms of ease of reaction, simplification of post-treatment, and ease of treatment of by-products It is preferable to use hydrogen peroxide, an organic peroxide, an organic peracid, or the like in view of simplicity of the reaction and improvement of the yield.

Examples of the solvent used in the reaction include acetic acid, alcohols such as methanol and ethanol, and polar solvents that can be arbitrarily mixed with water such as acetone and tetrahydrofuran. Among them, when acetic acid is used, the yield is extremely improved and the most preferable result is obtained.

According to the method of the present invention, the coloring of the product can be suppressed as much as possible by adding activated carbon at the final stage of the reaction, if necessary.

According to the method of the present invention, the general formula obtained by the above method is

Wherein L represents an alkyl group, an aryl group, an aralkyl group, a saturated alicyclic compound, M represents a hydrogen atom or a methyl group, and 4 equivalents or more of water. A base such as potassium oxide is added at a temperature not higher than the reflux temperature of the solvent by 3-10.
After reacting for a period of time, R is an alkyl group, an aryl group, an aralkyl group, a saturated alicyclic compound, R 'is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R "is a hydrogen atom. If the amount of the base used is less than 4 equivalents, the amount of the base required to complete the reaction cannot be obtained, and the two cyano compounds One or both of the groups are intermediate amides and the reaction stops, or the reaction does not proceed at all and the desired dicarboxylic acid cannot be obtained.

Examples of the solvent used in the method of the present invention include alcohols such as methanol and ethanol, and polar solvents such as acetone and tetrahydrofuran. General formula

Wherein L represents an alkyl group, an aryl group, an aralkyl group, a saturated alicyclic compound, and M represents a hydrogen atom or a methyl group. Methanol having the best solubility of the compound represented by the formula: When alcohols such as ethanol and ethanol are used, the yield can be increased or the reaction time can be shortened.

According to the method of the present invention, after the reaction is completed, the reaction solution is made acidic with diluted hydrochloric acid, diluted sulfuric acid, diluted nitric acid, diluted acetic acid, or the like.
Among them, dilute hydrochloric acid having good solubility in water at the same temperature,
Although it is preferable to use dilute acetic acid, the use of dilute hydrochloric acid is the most preferable result in consideration of the speed of shifting to the acidic side and the post-treatment surface.

After completion of the reaction, the hydrogen ion exponent (p
H = -log [H ⁺ ], which is hereinafter referred to as pH) is less than 6, preferably 1 to 5, more preferably 1 to 5.
The diluted acid is added so as to be 3. When the pH is 6 or more, the general formula

Wherein R is an alkyl group, an aryl group, an aralkyl group, a saturated alicyclic compound, R ′ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ″ is a hydrogen atom or methyl. Wherein only one of the two carboxyl groups of the compound represented by the formula

Embedded image (A represents an alkyl group, an aryl group, an aralkyl group, a cyclohexyl group, B represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and C represents a hydrogen atom or a methyl group.) In the solution. In the reaction solution, the general formula

(A is an alkyl group, an aryl group, an aralkyl group, a cyclohexyl group, and B is a hydrogen atom or a carbon atom having 1 carbon atom.
And alkyl groups C to C represent a hydrogen atom or a methyl group. There is a mixture of the mono-potassium salt of the compound represented by the formula (1) and potassium chloride produced by the addition of an acid, and the solubility in both solvents is almost the same. Therefore, solvent extraction is repeated many times to separate them. Alternatively, separation by column chromatography is required, which causes problems such as troublesome work or a large decrease in yield, and is not industrially useful. In the method of the present invention, by setting the pH of the reaction solution to an acidic region where both carboxyl groups can be protonated, the product can be precipitated without performing complicated operations such as solvent extraction and column separation as in the conventional method. The desired product can be obtained in high purity and high yield only by filtration.

In the method of the present invention, if necessary, the general formula

Wherein R is an alkyl group, an aryl group, an aralkyl group, a saturated alicyclic compound, R ′ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ″ is a hydrogen atom or methyl. May be converted into an ester, that is, a compound represented by the general formula:

Wherein R is an alkyl group, an aryl group, an aralkyl group, a saturated alicyclic compound, R ′ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ″ is a hydrogen atom or methyl. Is halogenated with a suitable halogenating agent, for example, thionyl chloride, thionyl bromide, phosphorus pentachloride, phosphorus pentabromide, a halogen molecule, and the like, and then methanol, ethanol, or the like. A known esterification method can be used, such as esterification with propanol, butanol or an isomer thereof, and in the case of methyl ester, a method of direct esterification with diazomethane can be used.

[0018]

As described above, in the method of the present invention, a phosphorus compound having a very small amount of effective and harmless and having excellent flame retardancy can be produced by a method which cannot be carried out by the conventional method, by simplifying the production process, reducing the cost, or increasing the cost. All problems such as quality improvement can be solved and manufactured. Further, the phosphorus compound obtained by the method of the present invention solves the problems of heat resistance, flame retardancy, stability, and the like, which have been hitherto known flame retardants. This is a very good thing with few problems.

[0019]

EXAMPLES The method of the present invention and the operation and effect thereof will be specifically described with reference to the following examples. In this example, phenylphosphine is used as a starting compound, but other phosphines described above can also be used.

Example 1 A 1-liter four-necked flask equipped with a stirrer, a dropping funnel, a nitrogen inlet tube and a reflux condenser was placed in an ice-water bath, and 250 cc of 220 g of phenylphosphine was added while flowing nitrogen gas.
Dissolve in acrylonitrile and pour into flask. Next, a 10N potassium hydroxide solution is added with stirring, and the mixture is cooled with ice water so that the internal temperature becomes 22 ° C. Then, 220 g (4.15 mol) of acrylonitrile is dropped from the dropping funnel over 45 minutes while adjusting the dropping speed so as to keep the internal temperature at 25 to 28 ° C. 28-3 after dropping
The reaction is performed at 5 ° C. for 3 hours. After the completion of the reaction, the reaction solution was separated, washed three times with 100 cc of saturated saline, and dried over anhydrous sodium nitrite. The reaction solution was distilled to crystallize a fraction at 215 ° -223 ° C./0.2 mmHg, recrystallized from ethanol, and 255 g of bis-
(2-cyanoethyl) -phenylphosphine (yield is 7
7%).

Example 2 Bis- (2-cyanoethyl)-obtained according to Example 1
250 g of phenylphosphine was dissolved in 2.5-fold acetic acid, and the solution was uniformly dissolved while maintaining the internal temperature at 60 ° C. 3 with stirring
204 g (1.61 mol) of 0% hydrogen peroxide aqueous solution at an internal temperature of 6
About 1 hour was added dropwise while maintaining the temperature at 0-70 ° C. Thereafter, activated carbon was further added at 75 ° C. for 15 minutes, and the mixture was heated to 100 ° C. and heated and stirred for 15 minutes. After cooling, evaporator
The acetic acid was removed by distillation to obtain 265 g (97% yield) of bis- (2-cyanoethyl) -phenylphosphine oxide.
If necessary, recrystallize with 2-propanol.

Example 3 The procedure of Example 2 was repeated except that the solvent was changed from acetic acid to methanol. In this case, the yield is slightly lower than that in Example 2, but the yield is 90%, which is a practical level.

Example 4 280 g of bis- (2-cyanoethyl) -phenylphosphine oxide obtained according to Example 1 was added to methanol 1
Dissolved in 300 ml and 541 g (bis- (2-
A solution prepared by dissolving potassium hydroxide (8 times equivalent to cyanoethyl) -phenylphosphine) in 560 ml of water was mixed and reacted at the reflux temperature of methanol for 5.5 hours. After the completion of the reaction, the reaction solution was adjusted to pH = 1 using dilute hydrochloric acid. White crystals gradually precipitated under stirring, and the precipitated crystals were collected by filtration, and 296 g of bis- (2-carboxyethyl) -phenylphosphine oxide (yield 90)
%).

Example 5 The same procedure as in Example 4 was carried out except that the amount of the base was changed to 4 times and 10 times the equivalent of bis- (2-cyanoethyl) -phenylphosphine oxide. In this case, the yield is almost the same as in Example 4. When the amount of the base is 4 equivalents, the yield is 8
If 6% and the amount of base is 10 equivalents, the yield is 91%.

Example 6 The same procedure as in Example 4 was carried out except that the solvent was changed from methanol to tetrahydrofuran. Although the yield is slightly lower than that of Example 4, the yield is 85-90%, which is a practical level.

In the methods from Example 4 to Example 6, the target product can be obtained with high purity only by adjusting the pH of the solution, and the process can proceed to the next step without requiring further purification.

Comparative Example 1 After completion of the reaction, a conventional literature (J. Am. Chem. So
c. , 81, 1103 pages (1959)), the reaction solution is neutralized (pH ≒ 7), and the amount of potassium hydroxide is adjusted with respect to bis- (2-cyanoethyl) -phenylphosphine oxide. The procedure was the same as that of Example 4, except that the amount was changed to 4 equivalents, but no white crystals were precipitated. In order to isolate the product from these mixtures, the solvent must be concentrated and complicated operations such as solvent extraction or column separation from the mixture of potassium chloride and the target product must be performed, which is not industrially useful. The yield after solvent extraction is 60% or less, and the yield after column separation is 30% or less.

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[Table 1]

──────────────────────────────────────────────────続 き Continued on the front page (56) References CHEMICAL ABSTRACT S82: 43518 (1975) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07F 9/53 CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] 1) A phosphine is reacted with a vinyl compound having a cyano group or a functional group capable of being converted to a cyano group to obtain a compound represented by the general formula (1): (1) wherein X represents an alkyl group, an aryl group, an aralkyl group, a saturated alicyclic compound, and Y represents a hydrogen atom or a methyl group. 2) Obtained in 1) Reacting the obtained compound with an oxidizing agent to obtain a compound represented by the general formula (2): (2) wherein L represents an alkyl group, an aryl group, an aralkyl group, a saturated alicyclic compound, and M represents a hydrogen atom or a methyl group. 3) Obtained in 2) The obtained product is allowed to react with a base, and after completion of the reaction, the reaction solution is acidified to a pH of less than 6 , and the reaction is carried out by the general formula (3). (3) (wherein, R represents an alkyl group, an aryl group, an aralkyl group, a saturated alicyclic compound, R ′ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ″ represents a hydrogen atom or a methyl group. A method for producing an organic phosphorus compound, which comprises converting the compound to a compound represented by the following formula: