JPH0641435B2 - Method for producing diphenyl ether dicarboxylic acid - Google Patents

Description

The present invention relates to diphenyl ether-3,3'- or 3,
It relates to a method for producing 4'-dicarboxylic acid.

All of these diphenyl ether dicardibonic acids are useful compounds as heat-resistant polymer raw materials, and the advent of an economical industrial production method has been desired.

Conventionally, the conventional method for producing these compounds is to condense an alkali metal salt of cresol and a halogenated toluene in the presence of a copper catalyst to obtain dimethyldiphenyl ether, which is then added to permanganate or a heavy salt. There is known a method of oxidizing with a chemical agent such as chromate, or with molecular oxygen in the presence of a catalyst to give a diphenyl ether dicarboxylic acid.

However, in the case of oxidation by chemicals, not only a large amount of permanganate or dichromate is required, but also a large amount of waste materials after the reaction are required, which is an industrially advantageous method. Is hard to say. In addition, the method using oxygen oxidation has problems such as complexity of catalyst recovery and use, complexity of equipment, interference of oxidation by impurities in raw materials, and risk of explosion, and it is difficult to call this method suitable for industrialization. .

From these viewpoints, it is easy to understand that the method of condensing such aromatic carboxylic acid derivatives and synthesizing the desired diphenyl ether dicarboxylic acid at once is the most preferable method. No one-step method is known.

In Japanese Patent Laid-Open No. 48-61443, m-
Sodium oxybenzoate or m-oxybenzoic acid methyl ester and brombenzene are reacted by heating in the presence of a copper powder catalyst and potassium carbonate to give m-phenoxybenzoic acid or m.
-A method for obtaining phenoxybenzoic acid methyl ester is described, but the yields of the desired product are 45% and 75%, respectively.
And low.

That is, in the method, when using methyl m-oxybenzoate in which monocarboxylic acid is esterified,
When using benzoic acid sodium salt, despite using expensive brombenzene in excess,
The desired product obtained is not in a satisfactory yield as an industrial process.

From these, like the raw materials used in the method of the present invention,
Condensation of compounds having a carboxylic acid group on both sides is expected to further reduce the yield, so it can be presumed that the one-step method has not been proposed.

Means for Solving the Problems The present inventors have earnestly studied the industrial production method of diphenyl ether-3,3′- and 3,4′-dicarboxylic acid and arrived at the present invention.

That is, the present invention has the formula (I) [In formula, -COOH is a 3 or 4 position with respect to a hydroxyl group. And m- or p-hydroxybenzoic acid represented by the formula (II) [In the formula, X represents Br or Cl, and -COOH is 3 with respect to X.
Or 4th place. ] The m- or p-halogenated benzoic acid shown by these is 8
-In the presence of a quinolinol copper complex catalyst, an alkali metal carbonate or an alkali metal hydroxide is used in an amount of 0.3 to 2.0 equivalents with respect to the hydroxyl group and carboxylic acid group of the compound of formula (I) and formula (II),
Aprotic polar solvent and alkylene glycol of the formula (IV). In the formula, R and R ′ are a hydrogen atom, a methyl or ethyl group, and n is an integer of 0 to 10], and the reaction is carried out by heating. [In the formula, -COOH is in the 3,3 'or 3,4' position. ] It is a manufacturing method of diphenyl ether-3,3 'dicarboxylic acid or diphenyl ether-3,4' dicarboxylic acid shown by these.

In the method of the present invention, there is no problem in yield even if chlorobenzoic acid is used as the starting halogenated benzoic acid without necessarily using expensive bromobenzoic acid. Further, these benzoic acids do not need to be used after conversion into ester, and both hydroxybenzoic acid and halogenated benzoic acid can be easily and inexpensively obtained as intermediates for pesticides and the like.

In the method of the present invention, the ratio of hydroxybenzoic acid to halogenated benzoic acid is preferably 0.5 to 2 molar ratio,
An equimolar ratio is particularly desirable.

In the present invention, the hydroxyl group and carboxylic acid group of these compounds are subjected to the condensation reaction prior to the reaction, after forming the phenolate and the carboxylate with an alkali metal. As the alkali metal, potassium or sodium is used as a hydroxide, carbonate, or bicarbonate, but the amount used is 0.3 to 2.0 equivalents for all hydroxy groups and carboxylic acid groups present in the raw material. , Preferably 0.5 to 1.5 equivalents. Especially 1.0
Around the molar ratio is preferable, and if it is less than 0.3 equivalent or exceeds 2.0 equivalents, the yield is lowered, which is not desirable.

Alkali metal salts of hydroxybenzoic acid and halogenated benzoic acid are prepared by heating these benzoic acids and caustic alkali, alkali carbonate, etc. in the presence or absence of an azeotropic agent such as toluene to distill off water. Is a general method and can be easily obtained according to a conventional method also in the present invention, but at this time, the produced salt is solidified and easily agglomerates.

Therefore, in a preferred embodiment of the present invention, a reactor is charged with a necessary amount of an alkali metal carbonate, bicarbonate or alkali metal hydroxide together with an aprotic polar solvent or alkylene glycol used in the condensation reaction described below, and the mixture is stirred. On the other hand, it is desirable to add hydroxybenzoic acid and halogenated benzoic acid as raw materials, dehydrate under heating, and then raise the temperature to a desired condensation reaction temperature to carry out the condensation reaction.

In the present invention, the copper-based catalyst used needs to be used as a copper complex of 8-quinolinol, and the reaction does not proceed with copper powder or the like used in the usual production of diphenyl ether. The 8-quinolinol copper complex may be added to the reaction after being adjusted in advance, but since the copper complex is easily formed by adding copper halide and 8-quinolinol to the reaction system, Copper halide and 8-quinolinol may be added to the above. Particularly suitable cuprous halides are cuprous chloride and cuprous bromide. The addition amount may be 0.001 to 0.2 molar ratio with respect to the raw material hydroxybenzoic acid. Further, the amount of 8-quinolinol added is appropriately in the range of 0.2 to 2.5 molar ratio with respect to the copper halide.

As the solvent used in the present invention, it is necessary to use an aprotic polar solvent, and commonly known organic solvents, particularly sulfolane, 1,3-dimethyl-2-imidazolidinone, N-methylpyrrolidone and dimethyl. Acetamide and the like are preferable. In addition, in this case, in order to further increase the yield, the following alkylene glycol may be used in combination.

As the alkylene glycol, a general formula (In the formula, R and R'are hydrogen atom, methyl group or ethyl group,
n shows the integer of 0-10. However, when n = 1, R represents a hydrogen atom and R'- represents a methyl group or an ethyl group. )
Those represented by, particularly diethylene glycol, cellosolve, diethylene glycol dimethyl ether, triethylene glycol and the like are advantageously used.

These solvents may be used alone, or two or more kinds may be mixed, and the mixing ratio thereof is not particularly limited.
When the aprotic polar solvent and the alkylene glycol solvent are used in combination, the mixing ratio is preferably about the same.

The amount of these solvents used is 2 to 2 of the raw material hydroxybenzoic acid.
20 times by weight is suitable, and 5 to 15 times by weight is particularly preferable.

The reaction is usually carried out at a temperature of 120 to 250 ° C, but 150 to 200 ° C is particularly suitable. The reaction time varies depending on the reaction temperature, solvent type, amount of catalyst, etc., but is usually 5 to 30 hours.

The product after the reaction is a dicarboxylic acid salt, and if it is dissolved in water or the solvent is recovered by distillation and then dissolved in water and the solution is acidified with an acid such as hydrochloric acid or sulfuric acid, diphenyl Ether dicarboxylic acid precipitates. A crude product can be obtained by over-washing it with water, and then drying it.However, if a higher-purity product is required, the crude product can be heated with methanol to dissolve and remove impurities. Can be purified by an acid precipitation method, a recrystallization method with a solvent such as dimethylformamide, or the like.

Examples will be described below.

Example 1 In a 300 ml four-necked flask equipped with a stirrer, a water separator, and a thermometer, 13.8 g (0.1 mol) of m-hydroxybenzoic acid and 15.6 g (0.1 mol of m-chlorobenzoic acid) were added. ), Potassium carbonate (purity 99.5%) 20.8 g (0.15 mol), 1,3
-Dimethyl-2-imidazolidinone 100 m1, cuprous chloride 0.4 g (0.04 mol), 8-quinolinol 0.6 g (0.0.
(04 mol) and 500 ml of toluene, and the mixture is heated with stirring, and the produced water is separated by azeotropic distillation with toluene under boiling. A salt was formed. Then, after the toluene was distilled off, it was further heated and agitated while maintaining the temperature at 170 ° C. for 20 hours to complete the reaction.

1,3-dimethyl-2-imidazolidinone was distilled off from the reaction solution under reduced pressure, the residue was dissolved in water to separate insoluble matter,
The obtained aqueous solution was acidified with concentrated hydrochloric acid, and the precipitated crystals were filtered, washed with water and dried to obtain 18.1 g (yield 70.2%) of diphenyl ether-3,3'-dicarboxylic acid. m
p247-251 ° C.

Examples 2 to 5 As in Example 1, sulfolane, N-methyl-2-pyrrolidone, diethylene glycol, and a mixed solvent of sulfolane and diethylene glycol (mixture 1:
Table 1 shows the results when each of 1) was used.

Example 6 m-Hydroxybenzoic acid 1 was added to the same reactor as in Example 1.
3.8 g (0.1 mol), p-chlorobenzoic acid 15.6 g (0.1 mol).
1 mol), potassium carbonate (99.5%) 20.8 g (0.15 mol), sulfolane 100 m1, cuprous chloride 0.4 g (0.04)
Mol), 0.6 g (0.04 mol) of 8-quinolinol and 50 ml of toluene, and the same procedure as in Example 1 was followed to obtain diphenyl ether 3,4'-dicarboxylic acid in a yield of 2
Obtained in 3.2 g (yield 90%). mp 283-286 ° C.

Example 7 A reactor similar to that in Example 1 was charged with 13.8 p-oxybenzoic acid.
g (0.1 mol), m-chlorobenzoic acid 15.6 g (0.1 mol), potassium carbonate (99.5%) 20.8 g (0.15 mol),
100 ml of sulfolane, 0.4 g (0.04 mol) of cuprous chloride, 0.6 g (0.04, mol) of 8-quinolinol and 50 ml of toluene were charged, the reaction temperature was 190 ° C., and the reaction time was 30 hours. The same procedure as in Example 1 was carried out except that the yield was 12.9 g (yield 50%) of a crude product of diphenyl ether 3,4'-dicarboxylic acid.

Claims (2)

[Claims] 1. A formula (I) [In the formula, -COOH is at the 3 or 4 position relative to the hydroxyl group] and m- or p-hydroxybenzoic acid represented by the formula (II) [In the formula, X represents Br or Cl, and -COOH is at the 3 or 4 position with respect to X. ] The m- or p-halogenated benzoic acid shown by these is 8
-In the presence of a quinolinol copper complex catalyst, an alkali metal carbonate or an alkali metal hydroxide is used in an amount of 0.3 to 2.0 equivalents based on the hydroxyl group and carboxylic acid group of the compounds of formula (I) and formula (II). Formula (III) characterized by heating reaction in a polar polar solvent [In the formula, -COOH is in the 3,3 'or 3,4' position. ] The manufacturing method of diphenyl ether-3,3 'dicarboxylic acid or diphenyl ether-3,4' dicarboxylic acid shown by these. 2. Formula (I) [In the formula, -COOH is at the 3 or 4 position relative to the hydroxyl group] and m- or p-hydroxybenzoic acid represented by the formula (II) [In the formula, X represents Br or Cl, and -COOH is at the 3 or 4 position with respect to X. ] The m- or p-halogenated benzoic acid shown by these is 8
-In the presence of a quinolinol copper complex catalyst, an alkali metal carbonate or an alkali metal hydroxide is used in an amount of 0.3 to 2.0 equivalents based on the hydroxyl group and carboxylic acid group of the compounds of formula (I) and formula (II). Proton polar solvent and alkylene glycol represented by formula (IV) [Wherein, R and R'are hydrogen atoms, methyl or ethyl groups, and n is an integer of 0 to 10] Formula (III) characterized by reacting by heating in a solvent [In the formula, -COOH is in the 3,3 'or 3,4' position. The manufacturing method of diphenyl ether-3,3 'dicarboxylic acid or diphenyl ether-3,4'-dicarboxylic acid shown by these.