JPS5912653B2 - Method for producing 1,4-dihydroxy-2-naphthoic acid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing 1,4-dihydroxy-2-naphthoic acid.

Specifically, the present invention uses 1,4-dihydroxynaphthalene as a raw material and directly carboxylates it with anhydrous powdered potassium carbonate and carbon dioxide gas in an organic medium to produce 1,4-dihydroxy-2-naphthalene. This invention relates to a method for efficiently producing acid.

Although 1,4-dihydroxy-2-naphthoic acid, which is the object of the present invention, is useful as a dye, pigment, and photosensitive material, an industrially advantageous manufacturing method has not yet been developed. do not have.

Attempts to synthesize 1,4-dihydroxy-2-naphthoic acid from 1,4-dihydroxynaphthalene include, for example,
According to Russig, J. Prakt-Chem-152, 30 (1900), the sodium or potassium salt of 1,4-dihydroxynaphthalene is prepared with alcoholic sodium or potassium in an alcoholic solvent. was synthesized and dried in a hydrogen stream, and then crystals of sodium or potassium salt of 1,204-dihydroxynaphthalene were heated under pressure of carbon dioxide gas.
There is a report that 1,4-dihydroxy-2-naphthoic acid was synthesized by reacting at 70°C for 20 to 30 hours and acid precipitation with dilute hydrochloric acid.

However, according to the knowledge of the present inventors, 1.
The alkali metal salt of 4-dihydroxynaphthalene is extremely unstable in the presence of air, and when it comes into contact with air, that is, molecular oxygen, it is easily oxidized and turns into a mail-like substance of unknown structure, resulting in 1,4-dihydro Oxynaphme 30 It is extremely difficult and practically impossible to stably extract the crystals of the alkali metal salt of phosphorus, and furthermore, the reaction between the alkali metal salt of 1,4-dihydroxynaphthalene and carbon dioxide gas is difficult. The disadvantage of a gas-solid phase reaction is that it tends to become thermally non-uniform at high temperatures, and because the contact efficiency of the gas-solid phase is poor, the reaction rate must be extremely slow. Become. As a result, a large amount of mail-like polymers are produced due to side reactions and a large amount of unreacted substances remain, resulting in a poor yield of 1,4-dihydroxy-2-naphthoic acid and difficulty in separation and purification. Therefore, it has been found that various difficulties must be overcome in carrying out this reaction industrially. Since the synthesis of 1,4-dihydroxy-2-naphthoic acid from 1,4-dihydroxynaphthalene is difficult, an alternative method that has been considered in the past is to synthesize 1,4-dihydroxy-2-naphthoic acid from phthalate ester and succinate ester. A method of synthesis is known (J. Anl. Chem.
SOc64798 (1942)).

However, this method has a very poor yield and is complicated due to the large number of steps, so it cannot be said to be an industrially advantageous production method.
The present invention provides 1,4-dihydroxynaphthalene by direct carboxylation reaction of 1,4-dihydroxynaphthalene.
- The purpose is to produce naphthoic acid industrially advantageously, by dissolving 1,4-dihydroxynaphthalene in a soluble organic medium and applying pressure while suspending and dispersing powdered anhydrous potassium carbonate. Reaction temperature under stirring: 130-20
It is characterized by carboxylation with carbon dioxide gas at 0°C.

Generally, the process of converting phenols into sodium or potassium salts using an aqueous sodium hydroxide or potassium hydroxide solution, dehydrating them, and then carboxylating them with carbon dioxide gas is well known as the Kolbe-Schmidt reaction. In the present invention, 1,4-dihydroxynaphthalene, which has two hydroxyl groups, is dissolved in a medium in which powdered anhydrous potassium carbonate is suspended and dispersed, and carbon dioxide gas is used to react with 1,4-dihydrooxynaphthalene in the same reaction system in one step. A method for producing 1,4-dihydroxy-2-naphthoic acid in high yield by selectively carboxylating a position is provided.

The present invention is specifically implemented as described below.

Powdered anhydrous potassium carbonate is used as the alkali source used in the present invention, and 1.゛5 times or more by mole, preferably 2.0 to 2
．． 5 molar amount: Used. When the amount of potassium carbonate added is 1.5 times the mole or less, 1,4-dihydroxy-2
- The yield of naphthoic acid is poor, the amount of unreacted substances increases, and the amount of tar-like polymers of unknown structure due to side reactions increases. The powdered anhydrous potassium carbonate used is of industrial grade, but in order to speed up the reaction rate, it is preferably in the form of fine particles, and the particle size is usually 200 microns or less, preferably 100 microns or less.

In the present invention, the reaction is carried out in a suspension state in a medium in which 1,4-dihydroxynaphthalene is soluble.

In the gas-solid phase reaction, the heat transfer rate of the powder is slow.

As a result, it is difficult to remove heat, resulting in thermal imbalance, and the contact efficiency with carbon dioxide gas is poor, resulting in a long reaction time and a high reaction temperature. As a result, the raw material 1,4-dihydroxynaphthalene and the intermediate product potassium salt of 1,4-dihydroxynaphthalene, which are unstable at high temperatures, are kept at high temperatures for a long time, resulting in poor yields in the reaction itself. Moreover, due to an increase in polymerized products due to side reactions or an increase in unreacted products, 1,4-dihydroxy-2-
Separation and purification of naphthoic acid becomes difficult. Therefore, in the present invention, it is advantageous to carry out the reaction in a medium. The medium used in the present invention is an organic solvent that is soluble in the raw materials and reaction products. Furthermore, the advantage of using a soluble organic solvent is that the reaction between 1,4-dihydroxynaphthalene and potassium carbonate is better when 1,4-dihydroxynaphthalene is dissolved in the solvent than when the reaction is in a solid-solid suspension state. The reaction is carried out while suspending powdered anhydrous potassium carbonate in the solution, which significantly increases the reaction rate, allows the reaction to be carried out at lower temperatures, reduces by-products, and produces 1,4-dihydrocarbonate in high yield. It is also possible to obtain oxy-2-naphthoic acid. Solvents that are soluble for the raw material 1,4-dihydroxynaphthalene and the reaction product include:
Ketones, esters, and alcohols with 4 or more carbon atoms,
Selected from polyhydric alcohols and their derivatives.

These solvents are not only soluble in 1,4-dihydronaphthalene, but also in 1,4-dihydroxy-2-naphthoic acid, which is a reaction product.
Moreover, it is convenient in separation and purification steps because it has low solubility in polymerized by-products.
Specifically, the following media are exemplified.

Ketones methyl n-propyl ketone, methyl n-butyl ketone,
Methyl isobutyl ketone, methyl n-amyl ketone, methyl n-hexyl ketone, diethyl ketone, ethyl n-
Butyl ketone, di-n-propyl ketone, diisobutyl ketone, acetone oil, tantyl oxide, cyclohexanone, methylcyclohexanone, acetophenone, esters n-butyl formate, isobutyl formate, amyl formate, acetic acid n
-propyl, isopropyl acetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate, n-amyl acetate, isoamyl acetate, methylisoamyl acetate, methoxybutyl acetate,
2-hexyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, cyclohexyl acetate, pentyl acetate, ethyl propionate, n-butyl propionate, isoamyl propionate C4 or higher alcohols n-butanol, isobutanol, n-amyl alcohol, in amyl alcohol, methyl amyl alcohol,
n-heptanol, cyclohexanol, secondary amyl alcohol, 3-pentanol, tertiary amyl alcohol,
Fudel oil, n-hexanol, 2-ethylbutanol,
2-hepshionol, 3-heptanol, n-oknonol,
2 octanol, 2 ethylhexanol, nonanol,
Examples include n-decanol, cyclohexanol polyhydric alcohol and its derivatives ethylene glycol dibutyl ether, ethylene glycol monobutyl ether acetate, ethylene glycol diacetate, diethylene glycol monobutyl ether acetate, ethyl cellosolve acetate, and ethylene glycol monobutyl ether. The ratio of the raw material 1.4 dihydrooxynaphthalene to the medium is related to the solubility of 1.4 to dihydrooxynaphthalene, but it is not necessarily necessary to form a complete solution, and the reaction may be carried out in a mostly dissolved state.

Usually 1,4-dihydroxynaphmelin: vehicle is 1:1
A range of 15 to 15 times by weight is substantial. In addition, in order to improve the contact efficiency between the raw material 1,4-dihydroxynaphthalene, powdered potassium carbonate, and carbon dioxide gas, the stirring speed and the structure of the stirrer should be adjusted to atomize and disperse the suspended matter and increase the reaction rate. important in meaning. It is generally said that the Kolbeschmitt reaction is inhibited by the introduction of water into the raw material system, but in the present invention, not only is the carboxylation reaction inhibited, but the raw materials and intermediate products are extremely unstable in strong alkalinity. Therefore, by controlling the water content in the raw material and medium mixture to 0.5% or less, preferably 0.3% or less so as not to become strongly alkaline, side reactions of polymers, etc. are suppressed.

Thus, the medium 1,4-dihydroxynaphthalene and powdered potassium carbonate are charged into the reactor and subjected to the carboxylation reaction, but stirring is required to completely replace the raw material medium suspension and the air present in the reactor space. Perform a purge operation by blowing in carbon dioxide gas to replace and eliminate air.

Next, the temperature is raised under pressure of carbon dioxide gas. This operation involves the use of 1,4-dihydroxynaphthalene, which is unstable in the presence of oxygen, and the intermediate product, the potassium salt of 1,4-dihydroxynaphthalene, 1,4-dihydrooxynaphthalene. This is extremely important in order to prevent deterioration due to polymerization of potassium salt of hydroxy-2-naphthoic acid. The reaction pressure is required to be 20 kg/Cd or more, preferably 30 kg/CrA or more, and the reaction is carried out under carbon dioxide gas pressure.

The reaction temperature is 130°C to 200°C, preferably 140 to 1
The temperature is 80°C.

If the reaction temperature is low, the carboxylation reaction will not proceed; on the contrary, 2
When the temperature exceeds 00 DEG C., the polymerization reaction of the raw materials and intermediate products progresses, and a slug-like black polymer and a green polymer are produced as by-products. The reaction time is 2 hours or more, preferably 4 to 8 hours.

Next, the method of the present invention will be explained using examples.

Example 1 1,4-dihydroxynaphthalene 80y1 Powdered anhydrous potassium carbonate with an average particle size of 100 microns 138y
A raw material suspension was prepared by charging 400 ml of methyl isobutyl ketone as a medium into a stirring autoclave having an internal volume of 11 and stirring and mixing.

The moisture content in this raw material and medium was 0.2%. Next, the gas inside the autoclave was purged at a pressure of 15k9/CrA while carbon dioxide gas was injected and stirred. After purging, perform the same operation again to completely replace the air in the autoclave, and then raise the temperature to 150°C at a rate of 3°C/min while injecting carbon dioxide gas, then stir at 600 rpm and under a pressure of 50 kg under carbon dioxide gas flow. /Cd and allowed to react for 6 hours. After the reaction, cool and depressurize and add 1% hydrosulfide aqueous solution 200ml.
After stirring for 30 minutes in an autoclave, the contents were taken out into a container purged with nitrogen, and while stirring, a 1:1 aqueous sulfuric acid solution was added to make it acidic, and methyl isobutyl ketone 70% was used as a solvent.
0 ml was added to dissolve 1,4 dihydroxy-2-naphthoic acid.

Next, filter this solution, separate the solution into a solvent layer and an aqueous layer,
After decolorizing the solvent layer with activated carbon and evaporating the solvent, 1.
Crystals of 4-dihydroxy-2-naphthoic acid (purity 94
．． 2%) 103.7f was obtained. The yield was 95.3 mol%, and unreacted 1,4-dihydroxynaphthalene was found to be 1.4% by liquid chromatography analysis. The above results are shown in Table 1. Examples 2 to 3 The reaction was carried out under the same conditions as in Example 1, except that powdered anhydrous potassium carbonate with an average particle size of 100 microns was used as 1727 and 1037, respectively, for 1,4-dihydroxynaphnoline 807. As a result, in the case of potassium carbonate 103V, that is, 1.
When the molar ratio of 4-dihydroxynaphthalene and potassium carbonate was set to 1:1.5, the unreacted rate increased.

The results are shown in Table 1. Example 4 1,4-dihydroxynaphthalene 80V, powdered anhydrous potassium carbonate 1387 with an average particle size of 100 microns
, 200 ml of methyl in butyl ketone was used as the medium.

The reaction was carried out under the same conditions as in Example 1, except that 900 ml of methyl isobutyl ketone was added as a solvent after the reaction was completed to dissolve 1,4-dihydroxy-2-naphthoic acid. The results are shown in Table 1. Example 5 The reaction was carried out under the same conditions as in Example 1 except that the reaction pressure was 351<9/CWi.

The results are shown in Table 1. Example 6 Reaction temperature was 140°C.
The reaction was carried out under the same conditions as in Example 1 except that the reaction time was 8 hours.

The results are shown in Table 1. Example 7 A reaction was carried out under the same conditions as in Example 1 except that the reaction temperature was 170°C and the reaction time was 5 hours.

The results are shown in Table 1. Examples 8 to 10 Reactions were carried out under the same conditions as in Example 1 except that diisobutyl ketone, physoamyl alcohol, and isobutyl acetate were used as reaction media, respectively.

However, when diisobutyl ketone or isobutyl acetate is used as a medium, 1,4-dihydroxy-
The amount of solvent for 2-naphthoic acid was 1,800 and 1,800 ml, respectively. The results are shown in Table 1. Comparative Example 1 (Reaction without solvent) 1,4-dihydroxynaphthalene 207, powdered anhydrous potassium carbonate with an average particle diameter of 100 microns, 60 V, was charged into a stirring autoclave with an internal volume of 11, and the raw materials were suspended by stirring and mixing. I prepared something.

The moisture content in this raw material and medium was 0.2%. Next, the gas inside the autoclave was purged at a pressure of 151<g/Cd while stirring and injecting carbon dioxide gas. After purging, the same operation was performed again to completely replace the air inside the autoclave, and the temperature increase rate was increased while injecting carbon dioxide gas. The temperature was raised to 175°C at a rate of 3°C/min, stirring speed was 600 rpm, and the pressure was 50 k under carbon dioxide gas flow.
The reaction was carried out for 7 hours while maintaining g/Cd. After the reaction, the autoclave was cooled and depressurized, and 200 ml of a 1% aqueous hydrosulfide solution was put into the autoclave. After stirring for 30 minutes, the contents were taken out into a nitrogen-purged container, and while stirring, a 1:1 aqueous sulfuric acid solution was added thereto for acid precipitation.

Next, methyl isobutyl ketone 300 resistant was added as a solvent to the precipitated 1,4-dihydroxy-2-naphthoic acid and dissolved, this solution was filtered, the slurry was separated into a solvent layer and an aqueous layer, and the solvent layer was decolorized with activated carbon, the solvent was evaporated, and the precipitated crystals were filtered and dried to obtain 20.1 V of crude 1,4-dihydroxy-2-naphthoic acid with a purity of 65.2%. Yield is 51.
2 mol %, and the unreacted rate of 1,4-dihydroxynaphthalene was 24.4%. The above results are shown in Table 1. Comparative Example 2 Powdered potassium carbonate 40f7, pressure 4
The reaction was carried out under the same conditions as Comparative Example 1 except that the reaction time was 5 kg/Cd and the reaction time was 12 hours.

Results first. Shown in the table. Comparative Example 3 The reaction was carried out under the same conditions as in Example 1, except that the reaction was carried out without replacing the air in the autoclave with carbon dioxide gas.

Claims (1)

[Scope of Claims] 1. 1,4-Dihydroxynaphthalene is dissolved in an organic medium that is soluble therein, potassium carbonate is suspended in this, and carbonic acid is added under pressure and stirring at a temperature of 130 to 200°C. A method for producing 1,4-dihydroxy-2-naphthoic acid, which comprises carrying out a carboxylation reaction using a gas. 2. The method according to claim 1, wherein the reaction is carried out at a molar ratio of 1,4-dihydroxynaphthalene and potassium carbonate of 1:1.5 or more. 3. The method according to claim 1, wherein the moisture content in the raw materials and medium is 0.5% by weight or less. 4. The method according to claim 1, which is carried out substantially in the absence of molecular oxygen.