JPH0437839B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides P-
The present invention relates to a method for producing a corresponding triphosphate or trithiophosphate by reacting a substituted phenol with phosphorus oxychloride or phosphorus thiochloride.

Phosphoric acid esters or trithiophosphoric acid esters (hereinafter both are collectively referred to as (thio)phosphoric acid esters) are useful compounds as raw materials for synthetic resins, flame retardants, agricultural chemicals, or intermediates thereof. In particular, tris(P-aminophenyl)(thio)phosphate is useful as an intermediate for tris(P-isocyanatephenyl)(thio)phosphate, which is useful as a raw material for polyurethane and the like. This tris(P-aminophenyl)(thio)phosphate ester can be obtained by synthesizing triphenyl(thio)phosphate, nitrating it, and then reducing it to the corresponding amine, or by synthesizing the sodium salt of P-nitrophenol. It is produced by reacting this with phosphorus oxychloride or phosphorus thiochloride at high temperature to produce the corresponding nitro compound, which is then reduced.Also, P-substituted phenol and phosphorus oxychloride or phosphorus thiochloride are reacted in the presence of an alkali. A method of manufacturing by directly reacting with is also known. For example, special public service in 1987
−25559 Publication P-substituted phenol represented by A method for producing the corresponding tris(P-substituted phenyl)(thio)phosphate ester is described below. However, since this method involves a reaction in the presence of water, the raw materials and reaction intermediates are susceptible to hydrolysis, making it difficult to sufficiently increase the yield. That is, in phosphorus oxychloride or phosphorus thiochloride, and the mono- or diester reaction intermediate, the chlorine atom bonded to the phosphorus atom contained therein is easily eliminated by hydrolysis.
The yield of triester was likely to be insufficient. In the invention described in the above-mentioned publication, the concentration of alkali is specified in order to prevent this hydrolysis, but the hydrolysis cannot be completely suppressed.

As a result of various research studies on methods to prevent the decrease in yield caused by hydrolysis, the present inventor found that when an alkali metal carbonate is present, a high yield of tri(thio)phosphate can be obtained under substantially anhydrous reaction conditions. It was discovered that esters can be produced. This is the gist of the present invention, that is, the formula [] P-substituted phenol represented by (X: nitro group, amino group, or N-acylamino group) and phosphorus oxychloride or phosphorus thiochloride are added under substantially anhydrous conditions in the presence of an alkali metal carbonate and a solvent. A method for producing a phosphoric acid ester or (thio)phosphoric acid ester represented by the following formula [], which is characterized by reacting with (Y: oxygen atom or sulfur atom, X: same as X in the above formula []).

In the present invention, since substantially no water is present in the reaction system, the above-mentioned problems caused by hydrolysis do not occur. That is, of course in the case of the invention described in the above-mentioned known examples, even when a non-aqueous solvent is used, when an alkali metal hydroxide is used, water is produced as a by-product due to the formation of an alkali metal sodium salt of P-substituted phenol. It is thought that water will not be produced as a by-product due to the use of carbonate. In the present invention, the reaction is thought to proceed via the following reaction, but this reaction has not been fully confirmed.

(M: Alkali metal) Examples of the alkali metal carbonate represented by M ₂ CO ₃ include lithium carbonate, sodium carbonate, and potassium carbonate, with sodium carbonate and potassium carbonate being particularly suitable. This alkali metal carbonate is suitably substantially anhydrous, and salts containing water of crystallization are not preferred. For example, for sodium carbonate,
In addition to anhydrous salts, there are decahydrate salts, heptahydrate salts, monohydrate salts, etc., but anhydrous salts (i.e., soda ash) are suitable.

According to the present invention, it is industrially advantageous because it can be synthesized all at once from P-aminophenol and phosphorus oxychloride or phosphorus thiochloride. There is no need to produce an alkali metal salt of P-nitrophenol, and tris(P-
Nitrophenyl)(thio)phosphate can be produced, which is subsequently reduced to produce tris(P-aminophenyl)(thio)phosphate in many cases. It is economically more advantageous than the method of producing acid esters. Also, N-acyl-P
The method for producing tris(4-acylaminophenyl)(thio)phosphate ester using -aminophenol as a raw material yields a compound with higher purity than when using the above-mentioned P-aminophenol as a raw material, and then this ( High purity tris(P-aminophenyl)(thio)phosphate can be easily obtained by hydrolyzing the thio)phosphate in the presence of an acid. In either case, a product with higher yield and purity can be obtained than the corresponding method of the invention described in the above-mentioned known example.

In carrying out the present invention, a method is usually used in which an alkali metal carbonate is added to the P-substituted phenol represented by the formula [] in the presence of a solvent, and phosphorus oxychloride or phosphorus thiochloride is added dropwise while cooling. Examples of the solvent include solvents inert to the reaction, such as toluene, xylene, chlorobenzene, O-dichlorobenzene, acetonitrile, diethylene glycol dimethyl ether, isopropyl ether, dioxane, acetone, methyl ethyl ketone, chloroform, dichloromethane, etc. Particularly preferred are ether solvents and ketone solvents. The amount of solvent to be used is not particularly limited, but approximately
Approximately 10 to 20 times the amount is appropriate. The amount of the alkali metal carbonate to be used is preferably about an equivalent mole or more, particularly 1 to 1.5 times the mole, relative to the P-substituted phenol, and it is usually appropriate to use about an equimolar amount or a slight excess. P
The amount of the -substituted phenol to be used may range from about 2.5 to 10 times the mole of phosphorus oxychloride or phosphorus thiochloride, but it is usually appropriate to use about 3 times the mole or slightly in excess. The reaction temperature is not particularly limited, but is suitably about 80°C or lower, especially about 0 to 40°C.
is preferred. The reaction time varies depending on the reaction temperature, but when the reaction is carried out at a suitable reaction temperature, the reaction time is about 1
~10 hours is appropriate. The (thio)phosphate ester produced in this manner contained unreacted P-substituted phenol, mono- or diester, and was concentrated by distilling off the solvent under reduced pressure, and then drained into water to filter out the precipitate. Afterwards, it is preferable to purify the crystalline material by washing it with a dilute aqueous alkaline solution. As a result, the unreacted substances and by-products become alkali salts and are dissolved and removed.

EXAMPLES The method of the present invention will be specifically explained below using Examples, but the present invention is not limited to these Examples.

Example 1 120 ml of acetone was added to a 300 ml four-necked flask equipped with a stirrer, thermometer, condenser, and dropping funnel.
Charge 9.18 g (0.066 mol) of P-nitrophenol and 9.12 g (0.066 mol) of potassium carbonate, and add 3.73 g (0.022 mol) of phosphorus thiochloride while stirring vigorously.
was added dropwise. During this time, the reaction temperature was 5℃.
The reaction mixture was cooled with ice water as shown below, and the reaction was continued for 5 hours with continued cooling.

After the reaction was completed, the acetone was distilled off and concentrated under reduced pressure, and then poured into 500 ml of 0.2% aqueous sodium hydroxide solution to precipitate. Wash the precipitate with water and heat at 60℃
10.18 g of tris(P-nitrophenyl)(thio)phosphate ester (P-
(Yield 97% based on nitrophenol) was obtained as a pale yellow powder. The melting point of this product was 179°C.

Comparative Example Acetone was added to the same reaction vessel used in Example 1.
200 ml and P-nitrophenol 13.91 g (0.1
mol), then 6.27 g of phosphorus thiochloride
(0.037 mol), and immediately 9.60 g (0.108 mol) of a 45% aqueous sodium hydroxide solution was added dropwise from the dropping funnel over 6 minutes with vigorous stirring. During this time, the mixture was cooled with ice water so that the reaction temperature was 8° C. or less, and the reaction was continued for 5 hours with continued cooling.

After the reaction was completed, it was concentrated under reduced pressure at 35°C and then 30% under ice cooling.
An aqueous solution of sodium hydroxide was added dropwise until the pH reached 11 to precipitate tris(P-nitrophenyl)(thio)phosphate, which was washed with water and dried under reduced pressure at 60°C. As a result, pale yellow crystals with a melting point of 179℃ were obtained at 8.59℃.
g (yield 54% based on P-nitrophenol) was obtained.

Example 2 3.37g of phosphorus oxychloride instead of phosphorus thiochloride
Tris(P-nitrophenyl) phosphate ester 9.94g (yield 97% based on P-nitrophenol)
%} was obtained as a white powder. The melting point of this substance is 156℃
It was hot.

Example 3 The procedure was repeated in the same manner as in Example 1, except that 7.22 g (0.066 mol) of P-aminophenol was used instead of P-nitrophenol, and 3.37 g (0.022 mol) of phosphorus oxychloride was used instead of phosphorus thiochloride. Tris (P
-aminophenyl) phosphate ester white crystals
5.64g (yield 69% based on P-aminophenol)
Obtained. The melting point of this product was 154°C.

Example 4 In the same reaction vessel as in Example 1, N-acetyl-P-
Aminophenol 9.99g (0.066mol), dioxane 120ml and sodium carbonate 7.0g (0.066mol)
3.73 phosphorus thiochloride while stirring vigorously.
g (0.022 mol) was added dropwise. During this time,
The mixture was cooled with water so that the reaction temperature was 30°C or less, and after the dropwise addition was completed, the reaction was continued at room temperature for 5 hours.

After the reaction was completed, it was concentrated under reduced pressure and poured into 500 ml of 0.2% aqueous sodium hydroxide solution to precipitate.
By washing the precipitate with water and drying under reduced pressure at 60°C, 11.18 g of white crystals of tris(4-acetylaminophenyl)thiophosphoric acid ester (99% yield based on N-acetyl-P-aminophenol) was obtained.
Obtained. The melting point of this product was 196°C.

Claims (1)

[Claims] 1 Formula [] P-substituted phenol represented by (X: nitro group, amino group, or N-acylamino group) and phosphorus oxychloride or phosphorus thiochloride are added under substantially anhydrous conditions in the presence of an alkali metal carbonate and a solvent. A method for producing a phosphoric acid ester or thiophosphoric acid ester represented by the following formula [], which comprises reacting with: (Y: oxygen atom or sulfur atom, X: same as X in the above formula [])