KR810001556B1 - Preparation of 2-hydroxynaphthalene carboxylic acids - Google Patents

Abstract

2-Hydroxynaphthalene carboxylic acid was prepd. by the reaction of carbon dioxide and a mixt. of 1 mole alkali β-naphtholate, 0.05-3 mole β-naphthol and light iol or kerosine at 180oC, 15 kg/cm2.G. Thus, 434 g light oil, 166 g sodium β-naphtholate and 144 g β-naphthol were reacted with carbon dioxide at 260oC, 3 kg/cm2.G for 3 hr in autochave. The reaction product was treated with 830 ml H2O at 100oC for 30 min to give 81.2 g 2-hydroxynaphthalene-3-carboxylic acid.

Description

Method for preparing 2-hydroxy naphthalene carboxylic acid

1 is a schematic of the apparatus used in Example 3. FIG.

2 is a schematic of the apparatus used in Examples 4 and 6. FIG.

3 is a schematic of the apparatus used in Examples 7, 8 and 9.

The present invention relates to a process for the preparation of 2-hydroxy naphthalenecarboxylic acid from alkali β-naphtholate.

Of 2-hydroxynaphthalenecarboxylic acid, 2-hydroxynaphthalene-3-carboxylic acid is particularly important as an intermediate for pigments and dyes. Generally it is prepared by reacting β-naphthol with alkali hydroxide to produce alkali β-naphtholate, which is then reacted with carbon dioxide under high pressure. In this method, it is suitable to dry the alkali β-naphtholate completely and effectively because in this reaction, even in the presence of a small amount of water, the yield of 2-hydroxy naphthalene-3-carboxylic acid is reduced. This conventional method requires a drying process time of 10 hours or more, complicated operation, high facility cost, and high manufacturing cost. To overcome this drawback, a method of azeotropically dehydrating a solution of alkali β-naphtholate in diphenyl, diphenyloxide or mixtures thereof and alkylnaphthyl-ene as a solvent has been proposed. However, this method is because the yield of the final product is not very high, the solvent is expensive, odor occurs, the melting point is too high or the boiling point is too low.

Conventionally, a solid-gas phase reaction known as the Kolbe-Schmidt reaction is used to react alkali β-Nattolate with idealized carbon. However, this method requires a long reaction time, i.e., 50 hours or more, because it is necessary to repeatedly carry out cart cyclization and recovery of by-product β-naphthol under reduced pressure. Also, the loss of β-naphthol is large because of the thermal nonuniformity of the reaction at high temperatures. The reaction is difficult to control because of the change in phase during the reaction, which makes it difficult to obtain stable yields. In order to solve these drawbacks, a method of catboxylating alkali β-naphtholate in the presence of excess β-naphthol at a pressure of 30 to 130 kg / cm 2 · G and alkali β- in the presence of nitrilotriacetic acid or ethylenediaminetetraacetic acid A method of cardboxifying naphtholate has been proposed. These methods are not satisfactory at all, for example, because the yield of the target is low, the reaction must be carried out under high pressure, and expensive materials must be used to construct the desired reaction apparatus.

On the other hand, the preparation of 2-hydroxy naphthalene-6- carboxylic acid is not known.

A method for preparing 2-hydroxynaphthalene-3- carboxylic acid from sodium β-naphtholate, optionally in the presence of β-naphthol, recovering β-naphthol formed or by-product and recovering the recovered β-naphthol It is advantageous to recycle N as sodium β-naphtholate.

It is also important to separate β-naphthol and the resinous material from the final product because 2-hydroxynathylene-3-carboxylic acid is a useful starting material for the preparation of pigments and dyes, and this material must be extremely high purity.

One known method for separating β-naphthol and dendritic material from an aqueous solution containing 2-hydroxy naphthalene-3-carboxylate is to precipitate a taart layer containing β-naphthol and resinous material from the aqueous solution. The tar layer is separated, the upper aqueous layer is cooled and filtered to separate β-naphthol, and the recovered material is distilled off under reduced pressure to recover β-naphthol. Another known method is to add water to the reaction mixture and extract the resulting aqueous solution containing β-hydroxynaphthalene-3-carboxinate with benzene, alkylbenzene or halogenated benzene to remove β-naphthol and the resinous material. This extract is distilled under reduced pressure to recover the extraction solvent and β-naphthol. In this method, the solvent used as the reaction medium in the reaction between alkali β-naphtholate and carbon dioxide is not used. Alkyl β-naphtholate is reacted with carbon dioxide using diphenyl, diphenyl ether, a mixture thereof, or alkylnaphthalene, and water and sulfuric acid are added to the reaction mixture to liberate the alkali β-naphtholate, and the solvent and the like are separated. It is also known to recover the β-naphthol-containing mixture by extracting the aqueous layer containing 2-hydroxynaphthalene-3-carboxylate and a solvent by countercurrent extraction. In this method, the resinous material must be transferred to the solvent layer to distill all of the solvent layer and the β-naphthol containing mixture.

As is well known, a mixture of alkali β-naphtholate and β-naphthol becomes liquid at the temperature at which 2-hydroxy or phthalenecarboxylic acid is formed by reaction with carbon dioxide. As the target, 2-hydroxynaphthylene carboxylate precipitates as a solid in the reaction system. The precipitated solids cover the liquid phase, so that the reaction system becomes uneven so that the reaction cannot be performed smoothly. This is because the reaction must be carried out at a high pressure of at least 30 kg / cm 2 · G or higher, and the yield decreases.

Alkaline β-naphtholate 1 has been studied by the present inventors to provide a good contact between alkali β-naphtholate and carbon dioxide during the reaction in the liquid state and to lower the melting point of the liquid mixture for the convenience of transportation in continuous operation. Alkali β when molar, β-naphthol 0.05-3 mol and a liquid mixture with light oil (ie gas oil) or kerosene, and the weight of light oil or kerosine is adjusted 0.1 to 5 times that of alkali β-naphtholate The distribution of β-naphthol is suitably carried out in the layers of the naphtholate β-naphthole liquid mixture and the diesel or ketocin layer, the specific gravity of the two layers approaching each other to form a good suspension, and then the reaction is increased by increasing the reaction rate. Pure 2-hydroxy or phthalene with reduced taar content in high yield by increasing the output per unit reactor To obtain the acid. As used herein, light oil (or gas oil) or kerosene means a petroleum hydrocarbon having a boiling point between about 150 and 400 ° C. suitably.

Further, the inventors of the present invention continued dehydration of alkali β-naphtholate and alkali β-naphtholate in an alkali β-naphtholate / β-naphthol mixture, and as a result, these alkali β-naphtholates were well dispersed in diesel oil or kerosene. It was found that dehydration of alkali β-naphtholate in this medium can be satisfactorily performed in a short time.

Thus, the dehydration of alkali β-naphtholate and the reaction of the dehydrated alkali β-naphtholate with carbon dioxide can be carried out continuously in light oil or kerosene. The amount of light oil or kerosene through the reaction of alkali β-naphtholate is preferably used in large amounts, for example, about 2 times 7 times the amount of alkali β-naphtholate to increase the efficiency of dehydration and transport. If light oil or kerosene is used to dehydrate alkaline β-naphtholate in an amount greater than five times its weight, excess diesel oil from the reaction mixture with alkali β-naphtholate, β-naphthol and the case or kerosene prior to reaction with carbon dioxide Or kerosene must be separated. This separation can be performed simply by the liquid phase separation method.

The present inventors also carried out a method of recovering 2-hydroxynaphthalene-3-carboxylic acid, recovering β-naphthol and separating the resinous substance in the form of a reaction mixture in an extremely pure form. In this method, water is added to the reaction mixture to separate the light oil or kerosene layer, and then acid is added to the aqueous solution layer to liberate the resinous material as a liquid and a taat layer containing β-naphthol and β-naphthol, At the same time, it was found that β-naphthol formed a mixture of a small amount of resinous material with about 13% water and a melting point of about 90 ° C. Alternatively, the taar layer containing β-naphthol and the resinous material may be precipitated as a liquid phase from the aqueous solution layer by adding acid to the reaction mixture to liberate β-naphthol and subsequently to separate the diesel or kesine layer. In each case the light oil or kerosene layer is substantially free of resinous material.

Based on the above findings, the present invention purifies a process for preparing 2-hydroxy or phthalenecart acid, which method comprises 1 mole of alkali β-naphtholate, 0.05 to 3 moles of β-naphthol and light oil or ketocin The liquid mixture of 0.1 to 5 parts by weight of an alkali β-naphtholate of C is reacted with carbon dioxide at a temperature of 180 ° C. or higher under a pressure of about 15 kg / cm 2 · G.

In a suitable embodiment of the present invention, alkali β-naphtholate or a mixture of alkali β-naphtholate and β-naphthol is dehydrated in light oil or kerosine and the resulting liquid mixture is reacted with carbon dioxide under the above conditions.

The desired product is separated from the reaction mixture, preferably by addition of water to the reaction mixture, the light oil or ketocin layer is separated before and after liberation of the unreacted alkali β-naphtholate with acid as β-naphthol, and the acid as necessary. Was added to the aqueous solution layer, and the aqueous layer was precipitated and separated from the aqueous layer containing the β-naphthol and the resinous material, and the β-naphthol was extracted from the aqueous solution layer using a hydrophobic extraction solvent. After treatment with acid, it is precipitated in aqueous solution layer after extraction. In this case, it is particularly advantageous to recover β-naphthol, such as alkali β-naphtholate obtained by using a light oil or kerosine layer and / or a taat layer and / or a solvent extraction layer and alkali hydroxide.

According to the present invention, the reaction of alkali β-naphtholate or β-naphthol with carbon dioxide, dehydration of raw materials, and manipulation of the reaction mixture can be carried out batchwise or continuously. However, it is particularly suitable to combine these process steps in a continuous manner. In the continuous process, the raw material is dehydrated as described above and reacted under the above conditions. Then, β-naphthol recovered from the reaction mixture as alkali β-naphtholate is recycled to the dehydration step.

In carrying out the process of the present invention, 1 mole of alkali β-naphtholate, 0.1 to 3 moles of β-naphthol, in particular 0.2 to 2 moles, light oil or kerosene (petroleum hydrocarbons are suitably 180 to 400 ° C.) 15 kg / cm 2 · G, liquid mixture having an alkali β-naphtholate of from 0.1 to 5 times, suitably 0.2 to 4 times, particularly suitably 0.5 to 3 times Is reacted with carbon dioxide at a temperature of at least 180 ° C., in particular between 250 and 28 ° C., under a pressure of carbon dioxide of 1 to 10 kg / cm 2 · G, particularly suitably 2 to 7 kg / cm 2 · G. If the amount of gas oil or kerosine exceeds the above upper limit, the yield is reduced. For example, when light oil or kerosine was used in an amount six times the weight of alkali β-naphtholate, the yield of the product based on alkali β-naphtholate was 10% or less. The reaction time is generally 25 hours. The above liquid mixture is prepared by a known method.

According to the present invention, alkali β-naphtholate or a mixture of this and β-naphthol was dehydrated in diesel oil or kerosene, and then a raw material liquid mixture of the above-described composition was prepared. Alkali β-naphtholate is reacted with an aqueous solution of β-naphthol and alkali hydroxide in diesel or kerosene. Or an aqueous solution of alkali β-naphtholate is added to the above-mentioned medium, and the mixture is stirred to suspend the aqueous alkaline β-naphtholate in the medium and then the suspension is dehydrated by heating in an inert gas such as nitrogen. This method can be carried out, for example, in combination with a method of dehydrating a mixture of an aqueous alkaline β-naphtholate solution with light oil or kerosene with a piston effluent. Treating a mixture of alkali β-naphtholate and β-naphthol and reacting β-naphthol with an aqueous solution of an equivalent or less alkali hydroxide in diesel or kerosene, or alkali β- or β-phthalate and β The aqueous mixture of naphthol was suspended in the medium and then dewatered in the same manner as described above. In addition, this method can be performed by adding a desired amount of β-naphthol at any stage of the dehydration method described above. In this dehydration method, a suitable dehydrating agent can be used.

After dehydration, β-naphthol is added as necessary to prepare a liquid mixture of the above-mentioned composition. This mixture is then reacted with carbon dioxide under the conditions described above. When the alkaline β-naphtholate is dehydrated in light oil or kerosene, the excess light oil or kerosine is removed from the resulting liquid mixture with alkali β-naphtholate, β-naphthol and light oil or kerosene by liquid phase separation, and then Further 2-naphthol is added to prepare a liquid mixture of the above-mentioned composition.

The operation of the reaction mixture is carried out by a conventional method. In a suitable embodiment of the invention, the operation of this reaction mixture is carried out as follows. After the reaction, the reaction mixture is cooled down and water is added. In the presence of β-hydroxynaphthylene-1-catalate, the mixture is heated to decompose it into β-naphthol. This mixture is then separated into a light oil or kerosene layer and an aqueous layer, and the light oil or kerosene layer is separated. Acids such as a mineral acid or an aqueous solution of the mineral acid are added to the aqueous solution layer to adjust the pH to 4 to 8, particularly 5 to 7 to liberate the unreacted alkali β-naphtholate as β-naphthol. It is suitable to wash the tar layer containing β-naphthol and the resinous substance with water, and this washing is used again as part of the water to be added. At this time water is added to the reaction mixture, the pH is adjusted to the desired level by acid, and then the mixture is separated into a light oil or kerosine layer and an aqueous layer, and the precipitated tar layer is separated from the aqueous layer. After separating the tar layer, [beta] -naphthol is separated from the aqueous layer using a hydrophobic extractant.

Useful extraction solvents include hydrocarbons such as benzene, toluene, xylene, hexane and cyclohexane, halogenated hydrocarbons such as chlorobenzene, dichloromethane, dichloroethane and chloroform, ether cyclohexane, diisobutyl ketone such as nitrobenzene and nitromethane and Ketones such as acetone, alcohols such as n-butyl alcohol having 4 or more carbon atoms, n-octyl alcohol and 2-ethylhexyl alcohol, and mixtures of these solvents. The extraction solvent is suitably used in an amount of 0.3 to 2 times, in particular 0.5 to 1.5 times, the volume of the aqueous solution layer, and the extraction is preferably performed at 30 to 110 ° C, particularly at 50 to 100 ° C.

[Beta] -naphthol in the reaction medium layer and the extraction solvent layer can be recovered by a known method, for example, by distillation under reduced pressure. It is suitable to recover with alkaline β-naphtholate solution using alkaline hydroxide solution. Β-naphthol of the tar layer is recovered by vacuum distillation or the like. The recovered aqueous solution of alkali β-naphtholate is recycled to the dehydration step described above, and β-naphthol is recycled to the dehydration step or the reaction step. The extraction described above removed a small amount of the reaction medium from the aqueous layer, so that no resinous material was substantially included in the extraction layer. After extraction with an acid, preferably with an aqueous solution of a mine, the pH of the aqueous layer can be adjusted to precipitate and separate the desired product.

The process of the present invention was carried out continuously and usually for 2 to 2 hours so that the yield of products based on alkali β-naphtholate reached about 45% and the yield based on spent β-naphthol exceeded 85%. . The recovery ratio of β-naphthol reached about 95%. The light oil or kerosene used as the reaction medium is inexpensive and has good properties. In addition, good results can be obtained even when the pressure of carbon dioxide is about 3 to 5 kg / cm 2 · G. The reaction apparatus can be made of inexpensive materials.

It is not necessary to distill β-naphthol during the reaction, and it can be recovered and recycled. Alkali β-naphtholate or a mixture of this and β-naphthol is dehydrated in a short time within several hours, and this step is carried out continuously. The aqueous solution of alkaline β-naphtholate is recovered from the β-naphthrone reaction mixture and the extraction solvent and recycled. For balance of the recycle material, a portion of the recycled alkaline β-naphthalate can be adjusted, for example, to be a major part of the total β-niphthol. In addition, the amount of β-naphthol recovered from the tar layer can be made approximately equal to the amount of β-naphthol added to the reaction system. The yield of the product based on β-naphthol consumed and the recovery ratio of β-naphthol were high as described above, and the loss of β-naphthol was extremely low.

In contrast to the known methods of vacuum distillation of the entire β-naphthol-containing mixture recovered, including the solvent, the process of the invention is extremely advantageous both operationally and economically. The reaction medium and the extraction solvent can be recycled without performing a heating or cooling step like fractionation type, and this method is extremely advantageous in terms of thermal economy. These solvents were hardly lost due to deterioration or other causes, and the recovery ratio of the reaction medium to the extraction solvent was 99.5% or more.

2-hydroxynaphthalenecarboxylic acid obtained by the method of the present invention had a purity of 99% or more, and the ratio of -naphthol contained as an impurity was 0.1% or less. The method of the present invention is advantageous in terms of thermal economy, since separation of the reaction medium layer, separation of the tar layer, extraction of the aqueous layer and acid precipitation of the product after the reaction can be carried out at about the same temperature. The process of the present invention is also capable of successively carrying out the various steps of forming 2-hydroxynaphthalenecarboxylic acid from β-naphthol and is extremely useful for commercial operation.

The invention is illustrated in more detail by the following non-limiting examples and the accompanying drawings.

Example 1

The autoclave was filled with 434 g of diesel oil (boiling point 200-310 ° C) and 166 g of sodium β-naphtholate, followed by addition of 144 g of β-naphthol. The mixture was reacted with carbon dioxide at a temperature of 260 ° C. for 3 hours under a pressure of 3 kg / cm 2 · G.

The reaction mixture was added to 830 ml of water and heated at 100 ° C. for 30 minutes to decompose 2-hydroxynaphthalene-1-carboxylate. This mixture was then separated into a light oil layer and an aqueous layer at 85 ° C. The pH of the aqueous layer was adjusted to 5.5 with hydrochloric acid, and the precipitated tar layer was separated at the same temperature as above. The aqueous layer was extracted with 500 ml of toluene at 80 ° C. PH of the aqueous solution layer was adjusted to 2.0 with hydrochloric acid at 85 degreeC. Subsequently, the aqueous layer was cooled to 40 ° C. and filtered to give 220-221 ° C. of 2-hydroxynaphthalene-3-carboxylic acid) melting point, 99.4% of purity, and 81.2 g of β-naphthol content (0.06%).

The yield of the product based on sodium β-naphtholate was 43.2%. 214.8 g of β-naphthol was recovered. The yield of the product based on the consumed β-naphthol was 85.0%, and the recovery ratio of β-naphthol was 95.2%.

Example 2

Instead of the gas oil of Example 1, 830 g of kerosene (boiling point 180-260 ° C.) was used, and the reaction was carried out at 250 ° C. under a pressure of 5 kg / cm 2 · G carbon dioxide for 5 hours.

The reaction mixture was carried out in the same manner as in Example 1 except that 500 m of methyl isobutyl ketone was used instead of toluene. Thus, 2-hydroxynaphthalene-3-carboxylic acid melting point 219-221 캜, purity 99.4%, β-naphthol content (0.05%) 76.1g were obtained. The yield of the product based on sodium β-naphtholate was 40.5%, 219.5 g of β-naphthol were obtained, and the yield of the product based on β-naphthol consumed was 85.1%. The recovery ratio of β-naphthol is 95.5%.

Example 3

Using the apparatus shown in FIG. 1, reaction and post-treatment were performed continuously.

83 kg of sodium β-naphtholate, 130 g of diesel oil (boiling point 200-310 ° C.), and 72 kg of β-naphthol were supplied to the mixer 1 in units of time, dispersed, and mixed. The dispersion was fed to a reactor 2 maintained at a carbon dioxide pressure of 3 kg / cm 2 · G at a flow rate of 285 kg per hour and reacted at 270 ° C. Retention time was 4.5 hours. The reaction mixture leaving the reactor 2 was cooled in a heat exchanger (not shown) and mixed with 420 liters of water per hour in the stirring tank 3. The temperature of the mixture was adjusted to 85 ° C., and the mixture was then charged to a separation tank 4, where it was separated into a light oil layer and an aqueous layer at 85 ° C. The upper gas oil layer was passed through a recovery apparatus (not shown) to recover β-naphthol. The pH of the bottom aqueous solution layer was adjusted to 5.5 with dilute sulfuric acid in the pH adjustment tank 5, which was separated at 85 ° C. in the separation tank 6. (Beta) -naphthol was collect | recovered from the separated lower tar layer using the vacuum distillation apparatus (not shown). The upper layer was sent from the separation tank 6 to the centrifugal extractor 7 and extracted with 250 liters of xylene per hour at 85 ° C. The xylene layer was sent to a recovery apparatus (not shown) to recover β-naphthol. The aqueous solution layer in the extraction tank 7 was sent to the acid precipitation tank 8, its pH was adjusted to 2.0 with dilute sulfuric acid at 85 ° C, and acid precipitation was performed. Thus, 2-hydroxynaphthalene-3-carboxylic acid (melting point 220-221 ° C, purity 99.5%, β-naphthol content 0.03%) was obtained in an amount of 42.3 kg per hour.

The yield of the product based on sodium β-naphtholate was 45.0%. β-naphthol was recovered at a rate of 106.0 kg per hour. The yield of product based on β-naphthol was 85.2% and the recovery of β-naphthol was 95.0%.

Example 4

The reaction was carried out continuously using the apparatus shown in FIG.

A mixture of 97.7 kg of sodium β-naphtholate 85% aqueous solution and 193 kg of diesel oil was placed in the evaporator 10 at a rate of 290.7 kg per hour, and dehydrated at 250 ° C. for 3 hours. The resulting mixture, consisting of 83 kg of sodium β-naphtholate and 166 kg of diesel oil (boiling point 200-310 ° C.), was placed in the mixer 11 at a flow rate of 249 kg / hrg. Β-naphthol was added in this mixer in an amount of 36 kg per hour and dispersed. The resulting dispersion was sent to a reactor 12 maintained at a carbon dioxide pressure of 3 kg / cm 2 · G at a flow rate of 285 kg / hr, and reacted at 270 ° C. for 4.5 hours.

The reaction mixture leaving reactor 12 was cooled in a heat exchanger (not shown) and then mixed with 500 liters of water per hour in stirring tank 13. This mixture was separated into a gas oil layer and an aqueous layer at 85 ° C. in a separation tank 14. β-naphthol was recovered from the upper gas oil layer using a recovery device (not shown). The lower aqueous solution layer was sent to the pH adjustment tank 15, where pH was adjusted to 5.5 by adding hydrochloric acid. This mixture was then transferred to a separation tank 16. (Beta) -naphthol was collect | recovered from the lower tar layer of the separation tank 16 using the vacuum distillation apparatus (not shown). The upper layer was extracted at 85 ° C. with xylene of the extractor 17 at a rate of 250 liters per hour. The xylene layer was sent to a recovery apparatus (not shown) to recover β-naphthol. The aqueous solution layer of the extraction tank 17 was sent to the acid precipitation tank 18, and the pH was adjusted to 2.0 by adding hydrochloric acid at 85 degreeC. Thus, 2-hydroxynaphthalene-3-carboxylic acid (melting point 220-221 ° C, purity 99.5%, β-naphthol content 0.3%) was obtained at a rate of 39.8 kg per hour.

The yield of the product based on sodium β-naphtholate was 42.3% and the amount of recovered β-naphthol was 72.2%. The yield of the product based on β-naphthol was 85.0%, and the recovery ratio of β-naphthol was 93.1%.

Example 5

498 g of diesel oil (boiling point 250-350 ° C.) and 166 g of sodium β-naphtholuate were charged into a high-pressure cooker, and 72 g 5 kg of β-naphthol was added while stirring. The mixture was reacted at 270 ° C. for 4 hours under a carbon dioxide pressure of 5 / cm 2 · G. The reaction mixture was added to 830 ml of water and heated at 100 ° C. for 30 minutes to decompose the 2-hydroxynaphthalene-1-catarate. This mixture was then separated into a light oil layer and an aqueous layer at 85 ° C. From the β- to naphthol as a light oil layer, an aqueous sodium β-naphtholate solution was extracted using an aqueous solution of sodium hydroxide. The pH of the aqueous layer was adjusted to 5.5 by adding hydrochloric acid, and the precipitated tar layer was separated at 85 ° C., and β-naphthol was recovered from the tar layer by vacuum distillation. Water (00 ml) was added to the aqueous layer, and the mixture was extracted with 650 ml of toluene at 80 ° C. Β-naphthol was extracted from the toluene layer as an aqueous solution of sodium β-naphtholate using an aqueous solution of sodium hydroxide. The pH of the aqueous layer was adjusted to 2.0 with hydrochloric acid, and the mixture was cooled to 40 ° C. and then filtered. Thus, 79.9 g of 2-hydroxynaphthalene-3-carboxylic acid (melting point 220 to 221 ° C, purity 99.6%, β-naphthol content 0.03%) was obtained.

The yield of the product based on sodium β-naphtholate was 42.5%. The total amount of sodium β-naphtholate 16.5 g (53.3 g of β-naphthol, 28.6 g of the light oil layer and 32. g of the toluene layer) was recovered. 60.6 g of β-naphthol was recovered from the tar layer. The yield of product based on β-naphthol consumed was 85.1% and the recovery ratio of β-naphthol was 93.1%. In addition, 497 g of diesel oil and 648.7 ml of toluene were recovered. This recovery amounted to 99.8% recovery. The recovered sodium β-naphtholate, β-naphthol, gas oil and toluene were recycled, and the same reaction and separation and extraction steps as above were carried out. There was no change in yield, and there was no change in the purity of 2-hydroxynaphthalene-3-carboxylic acid, the recovery ratios of β-naphthol, light oil and toluene.

When monochlorobenzene or n-butyl ether was used as an extraction solvent, the same result as above was obtained.

In addition, in the above method, the pH of the mixture was adjusted to 5.5 using hydrochloric acid before separating this into a light oil layer and an aqueous solution layer to obtain the same result.

Example 6

Although the apparatus used in FIG. 2 was used, the reaction was carried out continuously as follows without using the mixer 11.

A mixture of 97.7 kg of 85% aqueous solution of sodium β-naphtholate, 45.4 kg of β-naphthol and 99.6 kg of diesel oil (boiling point 200-310 ° C.) was placed in the evaporator 10 at a rate of 242.7 kg per hour, and at 250 ° C. for 1 hour. While dehydrated. (Beta) -naphthol distilled with diesel was collect | recovered by the separator (not shown). 83 kg of sodium β-naphtholate and 44.2 kg of a diesel oil dispersion were fed to a reactor 12 maintained at 83 kg 3 kg / cm 2 · G of carbon dioxide at a rate of 209.2 kg per hour and reacted at 270 ° C. The residence time was 4.5 hours. The reaction mixture was treated in the same manner as in Example 4 to give 2-hydroxynaphthalene-3-carboxylic acid (melting point 220-221 ° C., purity 99.6% β-naphthol content 0.02%) at a rate of 42.5 kg per hour. .

The yield of the product was 45.2% based on sodium β-naphtholate and 86.5% based on β-naphthol.

The recovered amount of β-naphthol was 77.6 kg per hour, and the recovery ratio of β-naphthol was 93.3%.

Example 7

The following reaction was carried out continuously using the apparatus shown in FIG.

83 kg of sodium β-naphtholate, 181 kg in the case of boiling point (boiling point 200 to 310 ° C.) and 57.2 kg of β-naphthol were fed in units of time, followed by mixing and dispersing them. Approximately one third of the gas oil layer (upper layer) formed in the separation tank is removed, and a small amount of sodium β-naphtholate is supplied as an aqueous solution of dissolved β-naphthol and sodium β-naphtholate, which is supplied to a recovery device (not shown). Recovered. The mixture remaining in the separation tank 1 was 81 kg of sodium β-naphtholate, 42.4 kg of β-naphthol, and 130 kg of diesel oil. The liquid mixture was supplied to the reactor 3 at a rate of 253.4 kg per hour, and reacted with carbon dioxide at a pressure of 5 kg / cm 2 · G and a temperature of 250 ° C. The residence time was 5 hours. The reaction mixture exiting the reaction tank 3 is cooled in a heat exchanger (not shown), mixed in an agitation tank 4 in an amount of 400 liters of water per hour, and then transferred to a separation tank 5, where the mixture is Was separated into a light oil layer and an aqueous layer at 85 ° C. [Beta] -naphthol was recovered from the upper gas oil layer using a recovery apparatus (not shown). The lower aqueous solution layer was transferred to the pH adjusting tank 6 and its pH was adjusted to 5.5 with dilute sulfuric acid, and then introduced into the separation tank 7. Β-naphthol was recovered from the bottom tar layer in the separation tank 7 using a vacuum distillation apparatus (not shown). The upper layer was sent to the extraction apparatus 8, where the xylene was extracted at a rate of 250? / Hr at 80 deg. The xylene layer was sent to a recovery apparatus (not shown) to recover β-naphthol. The aqueous solution layer of the extraction tank 8 was sent to an acid precipitation tank 9, where it was acid precipitated at pH 2.0 using dilute sulfuric acid at 85 ° C. Thus, 2-hydroxynaphthalene-3-carboxylic acid (melting point 220 to 221 ° C) was obtained at a rate of 41.3 kg per hour.

The yield of product was 45.0% based on sodium β-naphtholate and 85.6% based on β-naphthol consumed. The amount of β-naphthol was 75.6 kg per hour, and the recovery ratio of β-naphthol was 93.4%.

Example 8

In the mixer 1 shown in FIG. 3, 83 kg of sodium β-naphtholate, 181 kg of ketocin, and 57.2 kg of β-naphthol were mixed and dispersed every hour. About 2/3 of the kerosene layer was removed in the separation tank 2, and β-naphthol and sodium β-naphtholate were recovered therefrom as an aqueous solution of sodium β-naphtholate. A mixture of 79 kg of sodium β-naphtholate remaining in the separation tank 2, 27.6 kg of β-naphthol and 80 kg of kerosene was supplied to the reactor 3 at a rate of 186.6 kg / hr, and 5 kg / cm 2. It was reacted with carbon dioxide for 5 hours under the pressure of G. The reaction mixture was treated in the same manner as in Example 7, except for using hydrochloric acid to adjust the pH in the pH adjusting tank 6 and the acid precipitation tank 9, and toluene was used as the extraction solvent in the extraction tank. Thus, 2-hydroxy or phthalene-3-carboxylic acid (melting point: 218.5 to 221 ° C) was obtained in an amount of 40.3 kg per hour.

The yield of the product was 45.0% based on sodium β-naphtholate and 85.9% based on β-naphthol. The recovered amount of β-naphthol was 60.4 kg / hr, and the recovery ratio of β-naphthol was 92.3%.

Example 9

A mixture of 97.7 kg of 85% aqueous solution of sodium β-naphthol and 208 kg of diesel oil (boiling point 250-350 ° C.) was supplied to the evaporator at a rate of 305.7 kg per hour to dehydrate. Subsequently, 264 kg of the resulting mixture consisting of 83 kg of sodium β-naphthol and 181 kg of diesel oil is supplied to the mixer 1 (see FIG. 3), where β-naphthol is supplied at a rate of 57.2 kg per hour, and mixed Then dispersed. This dispersion was separated in separation tank (2). About two thirds of the upper gas oil layer was removed and transferred to a recovery apparatus in the same manner as in Example 7. A liquid mixture of 79.1 kg of sodium β-naphtholate, 27.5 kg of β-naphthol, and 79 kg of light oil remaining in the separation tank 2 was supplied to the reactor 3 at a rate of 185.6 kg per hour, and 3 kg / cm 2 · G It was reacted with carbon dioxide for 4.5 hours at a temperature of 270 ℃ under pressure. The reaction mixture was treated in the same manner as in Example 8. Thus, 40.5 kg of 2-hydroxy naphthalene-3-carboxylic acid (melting point 220 to 221 ° C) was obtained every hour.

The yield of product was 45.1% based on sodium β-naphtholate and 86.6% based on spent β-naphthol. The recovered amount of β-naphthol was 60.3 kg per hour, and the recovery ratio of β-naphthol was 92.6%.

Claims (1)

A method for producing 2-hydroxy naphthalene carboxylic acid by reacting alkali β-naphtholate with carbon dioxide, comprising: 1 mol of alkali β-naphtholate, 0.05 to 3 mol of β-naphthol per mol of β-alkarinaphtholate and light oil or A method for producing 2-hydroxy naphthalene carboxylic acid, characterized by reacting a liquid mixture of 0.1 to 5 times the alkali β-naphtholate of kerosine with a carbon dioxide at a temperature of 180 ° C. or higher and a carbon dioxide pressure of 15 kg / cm 2 · G. .

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