JPH03223230A - Production of hydroxy-2-naphthoic acid - Google Patents

Abstract

PURPOSE:To readily obtain the subject compound useful as an intermediate of a polymer material, dye, pigment, medicine or agricultural chemical in a high yield by reacting 2-naphtholpotassium with carbon dioxide in the presence of mono-trisubstituted phenolpotassium, etc. CONSTITUTION:2-naphtholpotassium is made to react with carbon dioxide in a solvent inert to the reaction or without using a reaction medium and in the presence of at least a compound expressed by formula I or formula II (R is all substituting groups except <=4C aliphatic hydroxyl group, <=4C aliphatic mercapto group and substituting group containing at least one of the hydroxyl group and the mercapto group; (n) is integer of 1-5, preferably 1, 2 or 3; (m) is integer of 1-5; (l) is integer of 0-4; R may be same or different in a case that (n) and (l) are respectively >=2). Hydroxy-2-naphthoic acid, preferably 3- or 6-hydroxy-naphthoic acid is generated as a stable dipotassium salt to afford the objective compound in yield higher than that in the published method.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for producing hydroxy-2-naphthoic acid using the Kolbe-Schmidt method.

<Prior Art> Hydroxy-2-naphthoic acid is an industrially important substance that has a wide range of uses, such as raw materials for polymeric materials, dyes and pigments, and raw materials or intermediates for medicines and agricultural chemicals. This material is generally produced by the Kolbe-Schmidt process, in which an alkali metal salt of 2-naphthol and carbon dioxide are reacted at high temperature and pressure. However, since the Kolbe-Schmidt method is a solid-gas phase reaction, the stirring efficiency is poor, preventing contact with carbon dioxide gas, the temperature distribution is large, the reaction takes a long time, and the yield is low. Other deficiencies have been pointed out. Afterwards, various methods were used to improve these methods, but mainly in an inert reaction medium, for example, in a mixture of diphenyl and diphenyl ether (Japanese Patent Application Laid-open No. 55
-35042) in isopropylnaphthalene (Unexamined Japanese Patent Publication No. 5
7-212139) in light oil (JP-A-54-7925)
No. 7, JP-A No. 63-146843), a method for carrying out the same reaction has been developed.

<Problems to be Solved by the Invention> However, 2-hydroxy-1-naphthoic acid, which is an isomer of hydroxy-2-naphthoic acid, can be obtained in a high yield of around 90% regardless of the use of a reaction medium. On the other hand, hydroxy-2-naphthoic acids such as 3-hydroxy-2-naphthoic acid and 6-hydroxy-2-naphthoic acid are usually obtained at a yield of only about 50%.

This is because monopotassium salt is the main product of 2-hydroxy-1-naphthoic acid, whereas dipotassium salt is the main product of 3-hydroxy-2-naphthoic acid and 6-hydroxy-2-naphthoic acid. It can be interpreted that it can only be obtained in low yields because it tends to be mainly produced as a salt.

Therefore, although some improvement was seen by the reaction in an inert medium, the yield of hydroxy-2-naphthoic acid is still far from being high.

Therefore, the present invention aims to provide a method for producing hydroxy-2-naphthoic acid, which can be easily obtained in high yield and has various uses including as a raw material for polymeric materials. purpose.

Means to solve problems〉 The above objects are achieved by the invention as described below.

That is, the present invention provides hydroxy-2-naphthoic acid by reacting potassium 2-naphthol and carbon dioxide in the presence of at least one compound represented by the following formula (I) or (II). A method for producing hydroxy-2-naphthoic acid is provided.

Formula (1) Formula (If) (In the above formulas (I) and (If), R is an aliphatic hydroxy group having 4 or less carbon atoms, an aliphatic mercapto group having 4 or less carbon atoms, and at least one of these. Represents all substituents other than those containing one in the structural unit.

In formula (1), n represents an integer of 1 to 5, and n is 2
In the above cases, R may be the same or different. formula(
In II), m represents an integer of 1 to 5, ρ represents an integer of O to 4, and when 1 is 2 or more, R may be the same or different. ) Also, hydroxy-2-naphthoic acid is 3-hydroxy-
2-naphthoic acid and/or 6-hydroxy-2-naphthoic acid are preferred, and 6-hydroxy-2-naphthoic acid is particularly preferred.

Preferably, the compound of formula (I) is a mono-, di- and/or tri-substituted potassium phenol.

Further, the reaction may be carried out using an inert medium or without using a medium.

The present invention will be explained in detail below.

In the present invention, when reacting potassium 2-naphthol and carbon dioxide, the following formula (I) and/or (II
) is present.

These serve as a potassium supply source and are added to facilitate the formation of the target product, hydroxy-2-naphthoic acid, as a dipotassium salt with high heat stability. Therefore, the efficiency of carbonating the naphthol potassium raw material is increased, the control range of the reaction temperature is also widened, and the reduction and/or removal operation of by-products can be facilitated.

Formula (1) and formula (II) used in the present invention are each represented as follows.

Formula (I) Formula (11) In the above formula (1) and formula (11), R has a carbon number of 4
All other substituents except for the following aliphatic hydroxy groups, aliphatic mercapto groups having 4 or less carbon atoms, and substituents containing at least one of these in the structural unit,
Examples include alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, amino groups, imino groups, halogen atoms, hydroxy groups (aromatic), nitro groups, and phenyl groups, and these groups can be used within the conditions of R above. If so, it may further have a substituent or a combination of a plurality of groups. For example, isopropyl group, aminoalkyl group, alkylaminoalkyl group, dialkylaminoalkyl group, acylamino group, halogenated alkyl group, nitroalkyl group, phenylalkyl group, methoxy group, alkylamino group, dialkylamino group, acyl group, styryl group. group, alkylphenyl group, alkoxyphenyl group, aminophenyl group, halogenated phenyl group, hydroxyphenyl group, and nitrophenyl group.

Among the substituents used in formulas (I) and (+i), preferable ones are electron-donating ones such as alkyl groups such as methyl groups and alkoxy groups such as methoxy groups, but phenyl groups are also suitable. .

Furthermore, in the present invention, the hydroxy-2-naphthoic acid produced is 3-hydroxy-2-naphthoic acid and/or 6-hydroxy-2-naphthoic acid.

The method of the present invention can be carried out through a reaction without using a reaction medium or through a method using an inert reaction medium, and can produce hydroxy-2-naphthoic acid in high yield even without using a reaction medium. You can also get it as a percentage. In particular, when the reaction temperature is higher than the melting point of the reaction mixture, the mixture, which is the starting material of the present invention, becomes liquid due to the melting point depression phenomenon. However, it is more advantageous in terms of stirring than the traditional solid-gas phase reaction, and
As the reaction progresses, the formula (I) and/or (II)
) is converted into the corresponding substituted phenol which is liquid or has a low melting point, and hydroxy-2-naphthoic acid can be obtained in high yield, so it can be used as a convenient method.

Therefore, whether to carry out the reaction using a reaction medium or not can be determined based on the melting point of the mixture used in the reaction.

The coexistence amount of the compound represented by formula (I) and/or (II) is 0.2 in terms of the number of equivalents of these potassium oxy groups, based on 2-naphthol potassium as the raw material.
The amount is 1 to 30 times equivalent, preferably 0.5 to 10 times equivalent, and more preferably 0.8 to 3 times equivalent.

For example, when dipotassium salt of dihydroxybenzene is used as the compound represented by the formula (11), the coexisting amount is 0.1 to 15 times the mole, preferably 0.25 to 5 times the mole. , more preferably 0.4 to 1.5 times the mole. Further, the amount of coexistence may be determined in consideration of the melting point of the mixture system, etc., and both should be taken into consideration, especially in the case of a method that does not use a reaction medium.

Further, the compound represented by formula (1) and/or (II) and/or 2-naphthol potassium may be used in whole or in part during and/or after the reaction.
There is an advantage that it can be recovered and reused as it is and/or as a free hydroxy compound.

In the present invention, the reaction temperature is 100°C or more, preferably 100 to 500°C, and the carbon dioxide pressure is not particularly limited, but for economical reasons, it is preferably normal pressure to 50k.
g/cm2 (G).

The carbon dioxide used in the present invention may be diluted or mixed with a gas that is inert to the raw materials and products under the reaction conditions, such as nitrogen, hydrogen, helium, argon, -carbon oxide, It may be mixed with hydrocarbons, phenols, etc.

In addition, blast furnace gas produced as a by-product in steel mills also contains carbon dioxide and can be used economically. When such a carbon dioxide mixed gas is used, the partial pressure of carbon dioxide may be set within the above range.

Furthermore, in the method of the present invention, carbon dioxide or carbon dioxide containing an inert gas is blown into the system using a pump, compressor, and/or blower, and/or circulated to agitate the system. It is also preferable to use it as a supplement.

Among the compounds represented by the formula (I), preferred examples are listed below.

Among the compounds represented by the above formula (1), monosubstituted phenol potassium is preferred, and the substitution position may be at the ortho, meta or para position, and cresol potassium and phenylphenol potassium (potassium salt of hydroxybiphenyl) are preferred. ) etc. are specifically mentioned.

Among the compounds represented by the above formula (I), potassium di-substituted phenol is preferred, and the two substitution positions may be in any combination, and 2.3-2.4-2
．． Specific examples include potassium 5-2.6-3.4- or 3.5-xylenol.

Among the compounds represented by formula (1), tri-substituted phenolic potassium is preferred, and any combination of the three substitution positions may be used, but 2,4.6-tri-substituted phenolic potassium has a high resistance to carbonation. It is preferred because it is inert, and 2,4.6-trimethylphenol potassium is specifically preferred.

In these cases, the amount of the substituted phenol potassium to be used may be determined within the above-mentioned range based on the number of equivalents of the potassium oxy group to the phenol potassium and the melting point.

In addition, reaction conditions such as reaction temperature and carbon dioxide pressure may be appropriately selected within the above-mentioned ranges.

Examples of the compound represented by the formula (II) include the above-mentioned dicaryrum salt of dihydroxybenzene. In addition, various other materials can be used.

The compounds represented by formula (I) and/or (II) may be used alone or in combination of two or more.

In the present invention, the method may be carried out in a batch method, a continuous method, or a combination of both methods, but a continuous method is preferred from the viewpoint of industrial significance.

When the method of the present invention is carried out in an inert reaction medium, examples of the medium include aromatic hydrocarbons, aromatic ethers, aromatic alkanes, aromatic alkenes, aromatic ketones, or hydrides thereof, or Examples include aliphatic petroleum hydrocarbons, aprotic polar solvents, and higher alcohols. These reaction media may be used alone or in combination of two or more as a mixed medium. For example, biphenyl, terphenyl, naphthalene, anthracene, ditolylethane, dihensyltoluene, methylnaphthalene, isopropylnaphthalene, G5250 (a mixture of aromatic compounds whose main component is methylnaphthalene), Neo
SK-o i 1 (media manufactured by Soken Kagaku Co., Ltd.), Dowtherm (mixture of biphenyl and diphenyl ether, etc.) Ethyl biphenyl, diphenyl ether, hydrogenated terphenyl, benzophenone, soluble oil and/or light oil with a boiling point of 150°C or higher, N, N- dimethylformamide, N, N
- Dimethylacetamide, dimethyl sulfoxide, hexamethylphosphoramide, higher alcohol having 5 to 15 carbon atoms, or a mixture thereof, preferably as long as it is insoluble in water and liquid at a temperature of 100°C or higher. However, it is more convenient for it to be liquid at room temperature or higher, and more preferably for it to have a boiling point of 200°C or higher.

Specifically, light oil with a boiling point of 250°C or higher, NeoSK-o
It is preferable to use il, Dowtherm, isopropylnaphthalene, and the like. The use of these media has the advantage that the reaction pressure can be easily controlled.

Furthermore, in order to carry out the reaction in a continuous manner using a reaction medium, the reaction medium may be selected taking into consideration the melting point, fluidity, and solubility of free phenols, and taking into account stiffness.

In addition, it is preferable that the reaction system be stirred in both the method not using a reaction medium and the method using a reaction medium.
In order to improve contact between the contents, high-speed rotation and/or vigorous shaking are preferred, and conditions that generate turbulence are even more preferred.

The 2-naphthol potassium and the compound represented by the formula (1) and/or (II) are preferably powders, and the particle size of any compound is preferably small (approximately 300 μm or less).

Particularly in reactions that do not use a reaction medium, particle size is an important factor.

<Examples> The present invention will be specifically described below based on Examples and Comparative Examples. In addition, the quantitative determination in the following Examples and Comparative Examples was performed by chromatography after acidifying the reaction product.

(Example 1) 5.581 m-cresol potassium 8.8 g of 2-naphthol potassium in dry powder form and a high boiling point fraction of light oil (
150-b mmHg) was charged into a pressure-resistant reaction vessel, and reacted under a carbon dioxide pressure of 3 Kg/crn'' (G) at 260°C for 1 hour with stirring at 11,000 rpm.

After the reaction, the reaction mixture was acidified and analyzed, and the yield of 6-hydroxy-2-naphthoic acid was 17.6% based on potassium 2-naphthol.

(Example 2) 5.46 g of 2-naphthol potassium in dry powder form, 3.
5-xylenol potassium 4.83g, and high boiling point fraction of light oil (150-230t/10mmHg) 25.8
g/cm in a pressure-resistant reaction vessel and carbon dioxide pressure of 3 g/cm.
2 (G) for 16 hours at 260-265°C, 1100
The reaction was carried out under stirring at 0 rpm. After the reaction, the reaction mixture was acidified and analyzed, and the yield of 6-hydroxy-2-naphthoic acid was 33.6 based on 2-naphthol potassium.
%Met.

(Comparative example) 5.7 g of 2-naphthol potassium in dry powder form and a high boiling point distillate of light oil (including 150~b, g at carbon dioxide pressure 3)
/cm' (G) for 1 hour at 260℃, 11000
The reaction was carried out under stirring with RP. After the reaction, the reaction mixture was acidified and analyzed, and the yield of 6-hydroxy-2-naphthoic acid was 7.3% based on potassium 2-naphthol.
Met.

<Effects of the Invention> According to the present invention, hydroxy-2-naphthoic acid can be produced as a stable dipotassium salt, and therefore hydroxy-2-naphthoic acid can be produced in a higher yield than conventionally.

Therefore, hydroxy-2-
Naphthoic acid can be supplied.

Claims (1)

[Scope of Claims] (1) Potassium 2-naphthol and carbon dioxide are reacted in the presence of at least one compound represented by the following formula (I) or (II) to produce hydroxy-
Hydroxy-2 characterized by obtaining 2-naphthoic acid
- A method for producing naphthoic acid. Formula (I) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ Formula (II) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ {In the above formulas (I) and (II), R has 4 carbon atoms
It represents all substituents other than the following aliphatic hydroxy groups, aliphatic mercapto groups having 4 or less carbon atoms, and substituents containing at least one of these in a structural unit. In formula (I), n represents an integer of 1 to 5, and when n is 2 or more, R may be the same or different;
In II), m represents an integer of 1 to 5, l represents an integer of 0 to 4, and when l is 2 or more, R may be the same or different. } (2) The method for producing hydroxy-2-naphthoic acid according to claim 1, wherein the hydroxy-2-naphthoic acid is 3-hydroxy-2-naphthoic acid. (3) The method for producing hydroxy-2-naphthoic acid according to claim 1, wherein the hydroxy-2-naphthoic acid is 6-hydroxy-2-naphthoic acid. (4) Claim 1, wherein the compound represented by formula (I) is a mono-, di- and/or tri-substituted potassium phenol.
4. The method for producing hydroxy-2-naphthoic acid according to any one of 3 to 3. (5) Hydroxy-2 according to any one of claims 1 to 4, wherein the reaction is carried out in a medium inert to the reaction.
- A method for producing naphthoic acid. (6) Claims 1 to 3 in which the reaction is carried out without using a reaction medium.
4. The method for producing hydroxy-2-naphthoic acid according to any one of 4.