JP3199618B2 - Method for producing 1,4-dihydroxy-2-naphthoic acid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing 1,4-dihydroxy-2-naphthoic acid.

[0002]

2. Description of the Prior Art 1,4-Dihydroxy-2-naphthoic acid is useful as an intermediate for dyes, pigments, photographic agents and the like, and several proposals have been made as industrial production methods thereof.
For example, J. Amer. Chem. Soc., 64 (1942) reports a method for producing from phthalic acid and a succinic ester. In J. Pract. Chem., [2] 62, 30 (1900), 1,4-dihydroxynaphthalene is reacted with alcoholic sodium or potassium hydroxide in an alcohol solvent to form a sodium or potassium salt thereof. It is reported that the desired naphthoic acid was synthesized by forming the crystals, drying them in a stream of hydrogen, and then reacting the crystals at 170 ° C. for 20 to 30 hours under carbon dioxide gas pressure, and salting out with dilute hydrochloric acid.

Recently, Japanese Patent Application Laid-Open Nos. 57-126443 and 57-128655 disclose 1,4-
A method of carboxylating dihydroxynaphthalene with carbon dioxide in an organic medium in the presence of fine anhydrous potassium carbonate is disclosed in JP-A-59-141537 and JP-A-60-104037. -A method of carboxylating dihydroxynaphthalene with carbon dioxide gas in the presence of an alkali metal compound and water has been proposed. JP-A-5-194314 discloses a method in which 1,4-dihydroxynaphthalene is dissolved in an organic medium to form an alkali metal salt using a metal alcoholate, and then carboxylated using carbon dioxide gas.

A method for synthesizing 1,4-dihydroxynaphthalene from 1,4-naphthoquinone is disclosed in Japanese Patent Application No.
157608 proposes a method in which catalytic reduction is carried out at 20 to 70 ° C. using 5% palladium carbon as a catalyst in a methanol solvent, followed by filtration of the catalyst and drying under reduced pressure.

[0005] In the method for producing from phthalic acid and succinic acid ester, the process is long and complicated, and the alkali metal salt of 1,4-dihydroxynaphthalene is very unstable, so that a large amount of by-products are formed and the yield is high. In addition, there are many difficulties in industrial production. Also, Japanese Patent Application Laid-Open No. 57-1264
No. 43 and JP-A-57-128655 use fine particles of anhydrous potassium carbonate having high hygroscopicity and react for a long time under high temperature and high pressure with the water content being 0.5% or less. Need to be
The operation of removing 1,4-dihydroxy-2-naphthoic acid from the reaction mixture is also complicated.

In the methods described in JP-A-59-141537 and JP-A-60-104037, the conversion is low and the raw materials need to be recovered.
The cooling rate after the reaction affects, and it is necessary to cool rapidly.

Further, in Japanese Patent Application Laid-Open No. 5-194314, an alkali metal alcoholate, which is industrially expensive, is used in the production reaction of an alkali metal salt, and the unstable compound 1,4-dihydroxy is used as a starting material. Uses naphthalene. As described above, various methods have been proposed as methods for producing 1,4-dihydroxy-2-naphthoic acid, which is useful as an intermediate for various products, but all of these methods are not necessarily industrially advantageous. At present, the development of an industrially advantageous production method is strongly desired.

[0008]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an industrially advantageous method for producing 1,4-dihydroxy-2-naphthoic acid.

[0009]

Means for Solving the Problems The present inventors have made 1,4-
As a result of various studies to find a method for industrially easy and advantageous production of dihydroxy-2-naphthoic acid in high yield, 1,4-dihydroxynaphthalene was treated with an alkali metal hydroxide in a specific organic medium. By treating with a metal salt and then with carbon dioxide gas, 1,4-dihydroxy-2-naphthoic acid can be produced in high yield, and 1,4-naphthoquinone, which is a stable compound alone, is selected as a raw material, In a specific organic medium, it is first subjected to catalytic reduction, then to a treatment with an alkali metal hydroxide, and finally to a treatment with carbon dioxide gas and then isolated. It has been found that high quality 1,4-dihydroxy-2-naphthoic acid can be produced with high and consistent yield. The present invention has been completed by further research based on such findings.

That is, the gist of the present invention is (1) 1,4-
Dihydroxynaphthalene is treated with an alkali metal hydroxide in a propylene glycol ether at 110 ° C. to 200 ° C. under an inert gas atmosphere to produce the alkali metal salt, and subsequently carboxylated using carbon dioxide gas. A process for producing 1,4-dihydroxy-2-naphthoic acid, characterized in that 1,4-dihydroxynaphthalene inactivates a catalytic reduction product of 1,4-naphthoquinone in a propylene glycol ether. The method according to the above (1), wherein the solution is obtained after filtration under a gas atmosphere.
(3) The propylene glycol ether is propylene glycol methyl ether, dipropylene glycol methyl ether, tripropylene glycol methyl ether, propylene glycol n-butyl ether, dipropylene glycol n-butyl ether, tripropylene glycol n-butyl ether, propylene glycol methyl ether Acetate, propylene glycol diacetate, propylene glycol
(4) The production method according to the above (1) or (2), which is at least one selected from the group consisting of phenyl ethers.
(5) The production method according to the above (1), wherein the alkali metal hydroxide is sodium hydroxide or potassium hydroxide, (5) the alkali metal hydroxide is added in an amount of 1 to 1 mol of 1,4-dihydroxynaphthalene as a raw material. (3) The method according to (1), wherein the catalytic reduction is carried out using a Raney nickel, platinum carbon or palladium carbon catalyst. Method.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. A first feature of the present invention is that in deriving 1,4-dihydroxynaphthalene in propylene glycol ether into its metal salt, an inexpensive alkali metal hydroxide is used instead of using an expensive metal alcoholate. is there. Compared with the method using a metal alcoholate, which is the most excellent conventional method, it is extremely inexpensive and extremely industrially advantageous.

The alkali metal hydroxide used in the metal salt formation reaction of 1,4-dihydroxynaphthalene includes:
Industrially, sodium hydroxide or potassium hydroxide can be mentioned, but sodium hydroxide is preferred. The amount used is twice the theoretical amount, but is usually 1,4.
1.5 to 3 times the molar amount of dihydroxynaphthalene. Even if it is used in a large excess, there is no corresponding improvement in yield, which is economically disadvantageous. It is preferably 2 to 3 moles, more preferably 2.0 to 2.4 moles. The reaction for forming an alkali metal salt is carried out in an inert gas atmosphere. The reaction temperature is usually from 110 ° C to 200 ° C, and the reaction time is from 3 to 9 hours. As the inert gas, nitrogen gas is preferable from an economic viewpoint.

The organic medium used in the reaction for forming the metal salt of 1,4-dihydroxynaphthalene includes propylene glycol ethers, especially propylene glycol methyl ether, dipropylene glycol methyl ether, tripropylene glycol methyl ether, and propylene glycol n-. Butyl ether, dipropylene glycol n-butyl ether, tripropylene glycol n-butyl ether, propylene glycol methyl ether acetate, propylene glycol diacetate, and propylene glycol phenyl ether are preferred. In particular, the boiling point must be higher than the reaction temperature of the metal salt formation reaction. When methanol or ethanol is used, the reaction yield becomes extremely low even when the reaction is performed under pressure.

A second feature of the present invention is that when producing 1,4-dihydroxy-2-naphthoic acid, a stable compound, 1,4-naphthoquinone, is selected as a starting compound.
First, 1,4-dihydroxynaphthalene is converted to 1,4-dihydroxynaphthalene by catalytic reduction, which is the first reaction, and is not isolated and subjected to treatment with an alkali metal hydroxide, which is the second reaction, in the same solvent under an inert gas atmosphere. To give a metal salt of 1,4-dihydroxynaphthalene, followed by a treatment with carbon dioxide gas in the same solvent and a carboxylation reaction to produce the desired 1,4-dihydroxy-2-naphthoic acid, Finally, it is a so-called one-pot reaction for isolating 1,4-dihydroxy-2-naphthoic acid from the reaction solution. Therefore, according to the method of the present invention, the unstable 1,
Since 4-dihydroxynaphthalene can be subjected to the next reaction under a reducing atmosphere without isolation, it is extremely advantageous in terms of yield and operation as compared with the conventional method.

Therefore, the organic medium used in the present invention includes the above-described catalytic reduction reaction, alkali metal salt formation reaction,
And a suitable solvent for all of the carboxylation reactions. Such an organic medium needs to have the following properties. That is,
First, 1,4-naphthoquinone, which is a raw material for the catalytic reduction reaction, is well dissolved, and 1,4-dihydroxynaphthalene, which is a product thereof, which is a raw material for the alkali metal salt generation reaction, is well dissolved. It is necessary that the alkali metal salt as a product be well dissolved. Further, as the organic medium used in the present invention, those which are stable without change over time due to heat and which do not cause side reactions such as esterification are preferable from the viewpoint of recycling and the like.

Examples of such an organic medium include propylene glycol ethers, especially propylene glycol methyl ether, dipropylene glycol methyl ether,
Examples include tripropylene glycol methyl ether, propylene glycol n-butyl ether, dipropylene glycol n-butyl ether, tripropylene glycol n-butyl ether, propylene glycol methyl ether acetate, propylene glycol diacetate, and propylene glycol phenyl ether.

Of these, those having a boiling point of 170 ° C. or more and a solubility parameter δ of 11 or less are preferred. This is because the carboxylation reaction, which is the third reaction, may be performed at 170 ° C to 180 ° C.
In addition, as the solubility parameter δ is lower than 11,
It has been found that the yield of dihydroxy-2-naphthoic acid is good. Where the solubility parameter δ is J.
A temperature-dependent material constant proposed by H. Hildebrand. Assuming that the molar heat of vaporization of the liquid is ΔH and the molar volume is V, δ = (ΔH / V) ^0.5 is defined. The amount of the organic medium used is 1,4-naphthoquinone or 1,4
3 to 20 times by weight, preferably 3 to 10 times by weight, of dihydroxynaphthalene.

The catalyst for catalytic reduction used in the present invention is not particularly limited as long as it is a usual metal catalyst for catalytic reduction. Among them, Raney nickel, platinum carbon,
And palladium carbon or the like is preferable. Palladium or platinum carbon, which is industrially recoverable and economical, is particularly preferred. The catalytic reduction is carried out under hydrogen pressure according to a known method.

In the process of the present invention, 1,4-naphthoquinone is catalytically reduced to 1,4-dihydroxynaphthalene, which is converted into an alkali metal salt without isolation, and subsequently, carbon dioxide gas is introduced into the reaction system. Carboxylate by blowing. The alkali metal salt forming reaction is carried out by 1,4-
Similar to the above-described conditions when dihydroxynaphthalene is used as a raw material, 1,1-naphthoquinone is usually used in an amount of 1: 1.
The reaction is performed using 5 to 3 moles, preferably 2 to 3 moles, more preferably 2 to 2.4 moles of an alkali metal hydroxide. The blowing amount of carbon dioxide gas may be a stoichiometric amount, but is usually slightly excessive. The reaction temperature for carboxylation is
In consideration of the stability and the reaction rate of the product, the temperature is preferably in the range of 50 to 180 ° C, more preferably 90 to 130 ° C. The carboxylation can be performed under normal pressure, but can also be performed under pressure. The pressure when the reaction is performed under pressure may be about 10 kg / cm ² or less.

After completion of the reaction, the obtained 1,4-dihydroxy-2-naphthoic acid may be isolated by any method. For example, the reaction solution is cooled if necessary and diluted with water. After neutralizing with an acid and filtering if necessary, the filtrate is made acidic, and the precipitated crystals are separated by filtration and washed with water to obtain 1,4-dihydroxy-2-naphthoic acid of high purity. it can. Examples of the acid used for neutralization and acidification include organic acids such as acetic acid, hydrochloric acid, and mineral acids such as sulfuric acid, and these acids may be used alone.
They can be used together. The pH during neutralization is preferably 8
To 5, more preferably 7.5 to 5.5, and the pH during crystallization is preferably around 1.

For isolation of 1,4-dihydroxy-2-naphthoic acid, the reaction solution is preferably neutralized and then diluted with water.
This is for improving the stirring property of the reaction solution after crystallization. The amount of water used for dilution is preferably equivalent to 10 times by weight, more preferably 3 to 5 times, the weight of the organic medium used for the reaction.
Weight times. After dilution with water, crystallization is carried out by acid precipitation. Thus, high purity 1,4-dihydroxy-
2-Naphthoic acid can be obtained industrially and advantageously in high yield.

The thus obtained 1,4-dihydroxy-
2-Naphthoic acid is useful as an intermediate for dyes, pigments, photographic agents and the like.

[0023]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. In the examples, parts and% represent parts by weight and% by weight, respectively.

Example 1 In a reaction vessel equipped with a stirrer, 189 parts of dipropylene glycol monomethyl ether was added at room temperature under a nitrogen atmosphere at room temperature.
47.4 parts of naphthoquinone was added, and 0.05 parts of 5% palladium carbon was further added. The temperature was raised to 80 ° C. while blowing hydrogen, and maintained at the same temperature. After the completion of hydrogen absorption, the catalyst was filtered under a nitrogen gas atmosphere and cooled to room temperature. The solvent was added so as to be 7.5 times the weight of the raw material, and then 25.7 parts of sodium hydroxide was added while blowing in nitrogen gas, and the temperature was raised and kept at 190 ° C for 2 hours. After the metal salt was formed, it was cooled to 100 ° C., and carbon dioxide gas was blown into the liquid. After gas absorption was no longer observed, air was blown for an additional hour.

Next, the mixture is cooled to 60 ° C.
Neutralization was performed by dropping 7.1 parts. This reaction solution was poured into 366.5 parts of warm water prepared in advance. pH 8
After confirming that the concentration was less than 35%, the generated by-product was separated by filtration, and 35% hydrochloric acid was added dropwise to the filtrate to adjust the pH to 1.0.
The resulting precipitate was collected by filtration after cooling, washed with water and air-dried at 50 ° C.
51.8 parts of 1,4-dihydroxy-2-naphthoic acid were obtained. As a result of a composition analysis of this product by HPLC, 1,4
The purity of -dihydroxy-2-naphthoic acid is 98.6%
And the yield was 84.6%. The purity was measured by a carboxylic acid neutralization titration method. The decomposition point is 19
It was 0 ° C or higher.

Example 2 A reaction was carried out under the same conditions as in Example 1 except that 1.2 parts of Raney nickel was used as a catalyst. As a result,
51.1 parts of crystals of dihydroxy-2-naphthoic acid were obtained. The purity of the crystals is 99.1% and the yield is 82.8%.
Met.

Example 3 A reaction was carried out under the same conditions as in Example 1 except that 0.05 parts of platinum carbon was used as a catalyst. as a result,
Crystals of 1,4-dihydroxy-2-naphthoic acid 52.2
Got a part. The purity of the crystals is 99.0% and the yield is 8
It was 4.5%.

Examples 4 to 6 The catalytic reduction reaction temperature was 60 ° C., 90 ° C., or 100 ° C.
The reaction was carried out under the same conditions as in Example 1 except that the reaction was carried out at a temperature of ° C. Table 1 shows the results.

[0029]

[Table 1]

Example 7 A reaction was carried out under the same conditions as in Example 1 except that potassium hydroxide was used in the reaction for producing an alkali metal salt. as a result,
Crystal of 1,4-dihydroxy-2-naphthoic acid 51.9
Got a part. The purity of the crystals is 98.9% and the yield is 8
It was 3.9%.

Example 8 The reaction was carried out under the same conditions as in Example 1 except that the reaction was carried out using propylene glycol diacetate as the organic medium. As a result, 52.0 parts of crystals of 1,4-dihydroxy-2-naphthoic acid were obtained. The purity of this crystal is 9
The yield was 9.0% and the yield was 84.1%.

Example 9 In a reaction vessel equipped with a stirrer, 173 parts of dipropylene glycol monomethyl ether was added to 173 parts of dipropylene glycol monomethyl ether at room temperature under a nitrogen atmosphere.
25.6 parts of dihydroxynaphthalene and 13.4 parts of sodium hydroxide were added, the temperature was raised, and the temperature was kept at 189 ° C for 2 hours. After the formation of the metal salt, the mixture was cooled to 100 ° C., and carbon dioxide gas was blown into the liquid. After gas absorption was no longer observed, carbon dioxide gas was blown for an additional hour.
Next, the mixture was cooled to 70 ° C., and neutralized by dropping 57 parts of 35% acetic acid. This reaction solution was poured into 193 parts of warm water prepared in advance. The resulting by-product was separated by filtration, and 35% hydrochloric acid was added dropwise to the filtrate to adjust the pH to 1.0. The resulting precipitate was cooled, collected by filtration, washed with water and air-dried at 50 ° C.
30.4 parts of 4-dihydroxy-2-naphthoic acid were obtained.
As a result of a composition analysis by HPLC of this product, the purity of 1,4-dihydroxy-2-naphthoic acid was 98.8% and the yield was 83.0%. The purity was measured by a carboxylic acid neutralization titration method. The decomposition point was 190 ° C. or higher.

[0033]

Industrial Applicability According to the method of the present invention, 1,4-dihydroxy-2-naphthoic acid useful as an intermediate such as a dye can be industrially advantageously produced.

──────────────────────────────────────────────────の Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C07C 51/15 C07C 65/11 CA (STN)

Claims (6)

(57) [Claims] 1. A method of treating 1,4-dihydroxynaphthalene with an alkali metal hydroxide in a propylene glycol ether at 110 ° C. to 200 ° C. under an inert gas atmosphere to form an alkali metal salt thereof. A method for producing 1,4-dihydroxy-2-naphthoic acid, comprising carboxylation using carbon dioxide gas. 2. The method according to claim 1, wherein the 1,4-dihydroxynaphthalene is a solution obtained after filtering a catalytic reduction product of 1,4-naphthoquinone in a propylene glycol ether under an inert gas atmosphere. The method according to claim 1, wherein: 3. The propylene glycol ether is propylene glycol methyl ether, dipropylene glycol methyl ether, tripropylene glycol.
Methyl ether, propylene glycol n-butyl ether, dipropylene glycol n-butyl ether, tripropylene glycol n-butyl ether,
3. The method according to claim 1, wherein the method is at least one selected from the group consisting of propylene glycol methyl ether acetate, propylene glycol diacetate, and propylene glycol phenyl ether. 4. The method according to claim 1, wherein the alkali metal hydroxide is sodium hydroxide or potassium hydroxide. 5. An alkali metal hydroxide is added in an amount of 1: 1 with respect to 1 mol of 1,4-dihydroxynaphthalene as a raw material.
The production method according to claim 1, wherein 5 to 3 mol is used. 6. The method according to claim 2, wherein the catalytic reduction uses a Raney nickel, platinum carbon or palladium carbon catalyst.