JP5739235B2 - Process for producing aromatic hydroxycarboxylic acid - Google Patents

Description

  The present invention relates to a method for producing an aromatic hydroxycarboxylic acid comprising a step of reacting an alkali metal salt of an aromatic hydroxy compound with carbon dioxide.

  Aromatic hydroxycarboxylic acids such as 4-hydroxybenzoic acid and 2-hydroxy-3-naphthoic acid are important as raw materials or intermediates for pigments / dyes, liquid crystals / liquid crystal molecules, pharmaceuticals / agrochemicals, etc. It is produced through a reaction between an alkali metal salt of a compound having a hydroxyl group and carbon dioxide.

  As the above reaction, a solid-gas phase reaction called Kolbe-Schmidt reaction has been used for a long time. There is a problem that the reaction control is difficult and a stable yield cannot be obtained.

  In order to remedy the drawbacks of this solid-phase reaction, the present applicant made good contact between the alkali metal salt of phenol and carbon dioxide when reacting the alkali metal salt of phenol with carbon dioxide in a liquid system. In order to allow the reaction to proceed and to lower the melting point of the liquid material for continuous operation and to facilitate transportation and the like, alkali metal salts of phenols, phenols and specific amounts in specific molar ratios It has been found and proposed that a good liquid-liquid suspension system is formed by using the above reaction medium (Patent Document 1).

  According to this method, a continuous reaction is possible, the reaction rate is increased, the production capacity per reactor is increased, and a pure aromatic hydroxycarboxylic acid having a small tar content is obtained.

  However, in this method, it is necessary to carry out the reaction at a high temperature exceeding 220 ° C. in order to increase the yield of the obtained aromatic hydroxycarboxylic acid. There was a problem of becoming.

  Therefore, from the viewpoint of environmental problems, it has been desired to establish a process for producing an aromatic hydroxycarboxylic acid that can produce the desired product in a high yield even under low temperature reaction conditions.

Japanese Examined Patent Publication No. 45-9529

  An object of the present invention is to provide a method for producing an aromatic hydroxycarboxylic acid that can produce an aromatic hydroxycarboxylic acid in a high yield regardless of the reaction conditions at a low temperature and has a low environmental load.

  As a result of intensive studies on the reaction between an alkali metal salt of an aromatic hydroxy compound and carbon dioxide, the present inventors have found that a specific ligand is present alone or as a metal complex, and is reacted at a low temperature. Nevertheless, the reaction proceeds, and an alkali metal salt of aromatic hydroxycarboxylic acid is obtained in high yield. By subjecting this to acid precipitation, the desired aromatic hydroxycarboxylic acid can be obtained in high yield. The headline and the present invention were completed.

  That is, the present invention relates to a method for producing an aromatic hydroxycarboxylic acid comprising a step of reacting an alkali metal salt of an aromatic hydroxy compound and carbon dioxide in a medium. On the other hand, the present invention provides a process for producing an aromatic hydroxycarboxylic acid characterized by comprising a step of reacting in the presence of 0.01 to 1.0 mol of a ligand alone or as a metal complex.

  According to the present invention, by using a ligand, the reaction between an alkali metal salt of an aromatic hydroxy compound and carbon dioxide is promoted even at a low temperature of about 20 ° C. to 220 ° C. The apparatus can be used to produce aromatic hydroxycarboxylic acids.

  The method of the present invention relates to a method comprising the step of reacting an alkali metal salt of an aromatic hydroxy compound with carbon dioxide in a medium.

In the present specification and claims, an “aromatic hydroxy compound” is a compound having a hydroxyl group on an aromatic ring having up to 2 rings, and having at least one substituent on the aromatic ring. A compound that may be present. Examples of the substituent include halogen atoms such as fluorine, bromine and chlorine, alkyl groups having 1 to 6 carbon atoms such as methyl, ethyl and propyl, alkoxy groups having 1 to 6 carbon atoms such as methoxy group and ethoxy group. Nitro group, sulfate group, amino group, phenyl group, benzyl group and the like.
Examples of the “aromatic hydroxy compound” used in the present invention include phenol, 1-naphthol, 2-naphthol and the like.

  In the present specification and claims, the “alkali metal salt of an aromatic hydroxy compound” refers to a salt in which the hydrogen atom of the phenolic hydroxyl group of the above “aromatic hydroxy compound” is replaced by an alkali metal. Examples of the metal include sodium, potassium, rubidium, cesium, lithium and the like.

  Examples of the alkali metal salt of the aromatic hydroxy compound used in the present invention include phenol sodium, phenol potassium, 2-naphthol potassium, 1-naphthol sodium, and 1-naphthol potassium. Among these, phenol sodium and phenol potassium And at least one selected from the group consisting of 2-naphthol potassium is preferably used.

  The alkali metal salt of the aromatic hydroxy compound to be subjected to the reaction needs to be sufficiently dehydrated. If the dehydration is incomplete, the reaction yield decreases. The dehydration is performed, for example, by heating in a vacuum state using an apparatus such as an evaporator, and the dehydration is performed until the water content becomes 1% or less, preferably 0.5% or less, more preferably 0.3% or less. It is good.

  In the present invention, in the reaction of an alkali metal salt of an aromatic hydroxy compound and carbon dioxide, 0.01 to 1.0 mol, preferably 0.02 to 0, relative to 1 mol of the alkali metal salt of the aromatic hydroxy compound. The reaction is carried out in the presence of 0.7 mol, more preferably 0.03 to 0.5 mol, and even more preferably 0.05 to 0.2 mol of a ligand alone or as a metal complex.

  By the presence of the ligand, the reaction proceeds even under low temperature conditions, and the target aromatic hydroxycarboxylic acid can be obtained in high yield.

  If the addition amount of the ligand is less than 0.01 mol relative to 1 mol of the alkali metal salt of the aromatic hydroxy compound, the reaction does not proceed sufficiently, and if the addition amount of the ligand exceeds 1 mol, the yield is obtained. However, it tends to decrease, which is disadvantageous in terms of cost.

  In the present specification and claims, the term “ligand” means a molecule or ion that can be directly bonded to a metal atom through a coordination bond to form a complex. The “metal complex” means a compound in which a ligand is bonded to a metal atom.

（I)
［式中、Ｒ_１〜Ｒ_３は、水素原子、炭素原子数１〜４のアルキル基またはフェニル基］；II.下記式(II)で示されるホスフィン化合物：

(II)
［式中、Ｒ_４〜Ｒ_６は、シクロヘキシル基、プロピル基、ｎ−ブチル基、ｔ−ブチル基またはフェニル基］；
III.下記式(III)で示されるビスオキサゾリン化合物：

(III)
［式中、Ｒ_７およびＲ_８は、水素原子または炭素原子数１〜４のアルキル基、Ｒ_９およびＲ_１０は、水素原子、炭素原子数１〜４のアルキル基またはフェニル基］；
IV.ピリジン、２，２’−ビピリジル、１，１０−フェナントロリンまたはそれらの誘導体から選択される含窒素芳香族化合物；
V.酢酸、トリフルオロ酢酸またはそれらの誘導体から選択される酢酸誘導体。 The ligand suitably used in the present invention is at least one selected from the following groups I to V:
I. A compound having a 2,4-pentandionato skeleton represented by the following formula (I):

(I)
[Wherein R _{1 to} R ₃ are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a phenyl group]; II. A phosphine compound represented by the following formula (II):

(II)
[Wherein R _{4 to} R ₆ are a cyclohexyl group, a propyl group, an n-butyl group, a t-butyl group, or a phenyl group];
III. Bisoxazoline compound represented by the following formula (III):

(III)
[Wherein R ₇ and R ₈ are a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ₉ and R ₁₀ are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a phenyl group];
IV. Nitrogen-containing aromatic compounds selected from pyridine, 2,2′-bipyridyl, 1,10-phenanthroline or derivatives thereof;
V. Acetic acid derivatives selected from acetic acid, trifluoroacetic acid or derivatives thereof.

Examples of the compound having a 2,4-pentanedionate skeleton of I include 2,4-pentanedionate, 3-methyl-2,4-pentandedionate, 3-ethyl-2,4-pentandedionate, 3 A compound having a substituent at the 3-position of 2,4-pentanedionate, such as -propyl-2,4-pentanedionate, 3-n-butyl-2,4-pentandedionate, and 2,4- Octandionato, 2,4-nonandionato, 1-phenyl-1,3-butanedionate, 2,2-dimethyl-3,5-hexanedionate, 3,5-heptanedionate, 2,6-dimethyl-3,5- Examples thereof include compounds having a substituent at the 1-position or 5-position of 2,4-pentanedionate, or both, such as heptaneedionate.
When the compound I is added not as a metal complex but as a ligand alone, it may be added in the form of a compound having a 2,4-pentanedione skeleton.

  Examples of the II phosphine compound include compounds having three substituents such as triphenylphosphine, tri-n-butylphosphine, tri-t-butylphosphine, and tricyclohexylphosphine.

  Examples of the bisoxazoline compound of III include 2,2-bis- (2-oxazolin-2-yl) propane, 3,3-bis- (2-oxazolin-2-yl) pentane, 5,5-bis- ( 2-oxazolin-2-yl) nonane, 2,2-bis [(4S) -4-phenyl-2-oxazolin-2-yl] propane, diethylmethylene-2,2′-bis (2-oxazoline), etc. Compounds.

  Examples of the nitrogen-containing aromatic compound of IV include pyridine, 2,2'-bipyridyl, 1,10-phenanthroline, and derivatives thereof, and examples of the derivative include those having a substituent such as methyl.

  Examples of the acetic acid derivative of V include acetic acid derivatives such as acetic acid and trifluoroacetic acid.

  In the present invention, as the ligand to be present in the reaction system, among the above, 2,4-pentanedionate, 2,2′-bipyridyl, 3-n-butyl-2,4-pentandedionate and acetic acid At least one selected from the group consisting of can be preferably used, and these ligands may be used alone or in the form of a metal complex. Particularly preferably, 2,4-pentanedionato is used alone or in the form of a metal complex.

  When the ligand is present as a form included in the metal complex, the metal complex includes, as a metal, Al, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Zr, Mo, Pd, Pb or A metal complex having Ru is preferable, and a metal complex having Mn, Cu or Pb is more preferable. Specifically, bis (2,4-pentanedionato) copper (II), bis (2,4-pentandedionato) lead (II) or tris (2,4-pentandedionato) manganese (III) Particularly preferably used.

  In the present invention, the medium used for the reaction is liquid at the reaction temperature and is inert to the reaction between the alkali metal salt of the aromatic hydroxy compound and carbon dioxide. Preferably, the medium has a boiling point of 220 ° C. or higher.

  As the medium, aliphatic, alicyclic or aromatic hydrocarbons or ether compounds having these residues are preferably used. For example, light oil, kerosene, gasoline, lubricating oil, white oil, alkylbenzene, alkylnaphthalene, Examples include ditriphenyl, hydrogenated triphenyl, diphenyl ether, alkylphenyl ether, alkyldiphenyl ether, higher boiling higher alcohols such as iso-octyl alcohol, and the like, and mixtures thereof.

  In addition, for the purpose of improving the solubility of the alkali metal salt of the aromatic hydroxy compound, an aromatic hydroxy compound such as phenol may be added to the reaction medium to be subjected to the reaction as a liquid mixture.

  The amount of the medium used is 0.5 times or more, preferably 0.5 to 20 times the weight of the alkali metal salt of the aromatic hydroxy compound.

  When an aromatic hydroxy compound is added to the reaction medium to form a liquid mixture, 0.05 to 3 mol of the aromatic hydroxy compound is preferably mixed with 1 mol of the alkali metal salt of the aromatic hydroxy compound.

  The reaction temperature between the alkali metal salt of the aromatic hydroxy compound and carbon dioxide is 20 to 220 ° C., preferably 50 to 215 ° C., more preferably 100 to 210 ° C. by allowing the ligand to exist alone or as a metal complex. And can be performed at low temperature. If the temperature is lower than 20 ° C, the reaction does not proceed. If the temperature is higher than 220 ° C, the reaction reaches a peak and energy is lost, and a side reaction may occur.

  The pressure during the reaction between the alkali metal salt of the aromatic hydroxy compound and carbon dioxide is preferably 1.5 MPa or less, preferably 0.1 to 1.0 MPa.

  The reaction time can be appropriately selected from several minutes to 15 hours, preferably 10 minutes to 10 hours, particularly preferably 20 minutes to 10 hours.

  By this method, aromatic hydroxy such as 2-hydroxybenzoic acid, 4-hydroxybenzoic acid, 2-hydroxy-3-naphthoic acid, 6-hydroxy-2-naphthoic acid, 2-hydroxynaphthalene-3,6-dicarboxylic acid, etc. Alkali metal salts of carboxylic acids can be obtained in high yield even under low temperature conditions. By subjecting these alkali metal salts of aromatic hydroxycarboxylic acids to conventional means such as acid precipitation, the target substances, 2-hydroxybenzoic acid, 4-hydroxybenzoic acid, 2-hydroxy-3-naphthoic acid, 6 Aromatic hydroxycarboxylic acids such as -hydroxy-2-naphthoic acid and 2-hydroxynaphthalene-3,6-dicarboxylic acid are obtained in high yield.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.

Example 1
In a 120 mL autoclave, phenol potassium 4.5 g (34 mmol), phenol 3.2 g (34 mmol), bis (2,4-pentandionato) copper (II) 0.89 g (3.4 mmol), And 45 g of light oil was added and stirred, and after replacing with nitrogen, it was sealed.

  Subsequently, after heating up a mixture to 100 degreeC, nitrogen was replaced by the carbon dioxide gas and it was made to react at 0.6 MPa for 1 hour. After completion of the reaction, the mixture was cooled, 18 g of water was added, and the mixture was stirred at 60 ° C. for 30 minutes.

  After cooling, the obtained medium layer and aqueous layer were quantitatively analyzed by high performance liquid chromatography. As a result, conversion from phenol potassium was 5.5% 4-hydroxybenzoic acid (POB), 2-hydroxybenzoic acid (SA). ) 8.3%.

Comparative Example 1
The reaction was performed in the same manner as in Example 1 except that bis (2,4-pentanedionato) copper (II) was not added. The obtained medium layer and aqueous layer were quantitatively analyzed by high performance liquid chromatography, but 4-hydroxybenzoic acid was not detected, and the amount of 2-hydroxybenzoic acid was also trace.

Example 2
Example 1 except that 1.38 g (3.4 mmol) of bis (2,4-pentanedionato) lead (II) was added instead of bis (2,4-pentandionato) copper (II) The reaction was conducted in the same manner.

  As a result of quantitative analysis of the obtained medium layer and aqueous layer by high performance liquid chromatography, conversion from phenol potassium was 5.6% 4-hydroxybenzoic acid and 10.4% 2-hydroxybenzoic acid.

Example 3
Example 1 except that 1.2 g (3.4 mmol) of tris (2,4-pentanedionato) manganese (III) was added instead of bis (2,4-pentandionato) copper (II) The reaction was conducted in the same manner.

  As a result of quantitative analysis of the obtained medium layer and aqueous layer by high performance liquid chromatography, conversion from phenol potassium was 7.0% 4-hydroxybenzoic acid and 11.9% 2-hydroxybenzoic acid.

Example 4
The reaction was conducted in the same manner as in Example 1 except that 0.34 g (3.4 mmol) of 2,4-pentanedione was added instead of bis (2,4-pentanedionato) copper (II).

  As a result of quantitative analysis of the obtained medium layer and aqueous layer by high performance liquid chromatography, the conversion from phenol potassium was 3.8% of 4-hydroxybenzoic acid and 6.9% of 2-hydroxybenzoic acid.

Example 5
In a 120 mL autoclave, 4.5 g (38.8 mmol) phenol sodium, 3.2 g (34 mmol) phenol, 1.01 g (3.9 mmol) bis (2,4-pentanedionato) copper (II) ), And 45 g of light oil were added, stirred, purged with nitrogen, and sealed.

  Subsequently, after heating up a mixture to 120 degreeC, nitrogen was replaced with the carbon dioxide gas and it was made to react at 0.6 MPa for 1 hour. After completion of the reaction, the mixture was cooled, 18 g of water was added, and the mixture was stirred at 60 ° C. for 30 minutes.

  After cooling, the obtained medium layer and aqueous layer were quantitatively analyzed by high performance liquid chromatography. As a result, the conversion rate from phenol sodium was 3.1% 4-hydroxybenzoic acid and 32.7% 2-hydroxybenzoic acid. there were.

Comparative Example 2
The reaction was performed in the same manner as in Example 5 except that bis (2,4-pentanedionato) copper (II) was not added. As a result of quantitative analysis of the obtained medium layer and aqueous layer by high performance liquid chromatography, the conversion from phenol sodium was trace amount of 4-hydroxybenzoic acid and 0.8% of 2-hydroxybenzoic acid.

Example 6
The reaction was conducted in the same manner as in Example 5 except that 0.78 g (7.8 mmol) of 2,4-pentanedione was added instead of bis (2,4-pentanedionato) copper (II).

  As a result of quantitative analysis of the obtained medium layer and aqueous layer by high performance liquid chromatography, conversion from phenol sodium was 3.9% 4-hydroxybenzoic acid and 33.9% 2-hydroxybenzoic acid.

Example 7
The same procedure as in Example 1 was conducted except that 1.06 g (6.8 mmol) of 3-n-butyl-2,4-pentanedione was added instead of bis (2,4-pentanedionato) copper (II). The reaction was performed.

  As a result of quantitative analysis of the obtained medium layer and aqueous layer by high performance liquid chromatography, the conversion rate from phenol potassium was 3.4% 4-hydroxybenzoic acid and 6.3% 2-hydroxybenzoic acid.

Example 8
The reaction was conducted in the same manner as in Example 1 except that 1.91 g (6.8 mmol) of tricyclohexylphosphine was added instead of bis (2,4-pentanedionato) copper (II).

  As a result of quantitative analysis of the obtained medium layer and aqueous layer by high performance liquid chromatography, the conversion rate from phenol potassium was 5.2% 4-hydroxybenzoic acid and 9.9% 2-hydroxybenzoic acid.

Example 9
Instead of bis (2,4-pentanedionato) copper (II), 0.67 g (1.7 mmol) of diethylmethylene-2,2′-bis (2-oxazoline) copper acetate (II) was added. Was reacted in the same manner as in Example 1.

  As a result of quantitative analysis of the obtained medium layer and aqueous layer by high performance liquid chromatography, the conversion from phenol potassium was 5.6% 4-hydroxybenzoic acid and 10.8% 2-hydroxybenzoic acid.

Example 10
In the same manner as in Example 1 except that 1.15 g (3.4 mmol) of 2,2′-bipyridyl copper acetate (II) was added instead of bis (2,4-pentanedionato) copper (II). Reaction was performed.

  As a result of quantitative analysis of the obtained medium layer and aqueous layer by high performance liquid chromatography, the conversion rate from phenol potassium was 9.5% 4-hydroxybenzoic acid and 14.8% 2-hydroxybenzoic acid.

  The results of Examples 1 to 10 and Comparative Examples 1 and 2 are shown in Table 1.

Example 11
In a 120 mL autoclave, 4.2 g (23 mmol) 2-naphthol potassium, 0.6 g (2.3 mmol) bis (2,4-pentanedionato) copper (II), and linear alkylbenzene (alkene) (200P) 42 g was added, stirred, purged with nitrogen, and sealed.

  Next, the temperature of the mixture was raised to 210 ° C., and nitrogen was replaced with carbon dioxide gas and reacted at 0.3 MPa for 4 hours. After completion of the reaction, the reaction mixture was cooled, 16.8 g of water was added, and the mixture was stirred at 90 ° C. for 60 minutes.

  After cooling, the obtained medium layer and aqueous layer were quantitatively analyzed by high performance liquid chromatography. As a result, conversion from 2-naphthol potassium was found to be 8.1% for 2-hydroxy-3-naphthoic acid (BON3), 6- Hydroxy-2-naphthoic acid (BON6) was 1.6%.

Comparative Example 3
The reaction was conducted in the same manner as in Example 11 except that bis (2,4-pentanedionato) copper (II) was not added. As a result of quantitative analysis of the obtained medium layer and aqueous layer by high performance liquid chromatography, the conversion rate from 2-naphthol potassium was 2.4% 2-hydroxy-3-naphthoic acid (BON3), 6-hydroxy-2. -It was 0.8% of naphthoic acid (BON6).

Example 12
The reaction was conducted in the same manner as in Example 11 except that 0.46 g (4.6 mmol) of 2,4-pentanedione was added instead of bis (2,4-pentanedionato) copper (II).

  As a result of quantitative analysis of the obtained medium layer and aqueous layer by high performance liquid chromatography, conversion from 2-naphthol potassium was 7.3% of 2-hydroxy-3-naphthoic acid (BON3), 6-hydroxy-2. -It was 2.0% of naphthoic acid (BON6).

Example 13
Example 11 was repeated except that 0.72 g (4.6 mmol) of 3-n-butyl-2,4-pentanedione was added in place of bis (2,4-pentanedionato) copper (II). The reaction was performed.

  As a result of quantitative analysis of the obtained medium layer and aqueous layer by high performance liquid chromatography, the conversion from 2-naphthol potassium was 8.8% 2-hydroxy-3-naphthoic acid (BON3), 6-hydroxy-2. -It was 2.5% of naphthoic acid (BON6).

Claims (6)

In a method for producing an aromatic hydroxycarboxylic acid comprising a step of reacting an alkali metal salt of an aromatic hydroxy compound and carbon dioxide in a medium, 0.01 mol per mol of the alkali metal salt of the aromatic hydroxy compound. the 1.0 moles of ligand is present as a single or a metal complex saw including a step of performing the reaction, said ligand is at least one selected from the following group of I~V A method for producing an aromatic hydroxycarboxylic acid.
I. A compound having a 2,4-pentanedionate skeleton represented by the following formula (I):

(I)
[Wherein R _{1 to} R ₃ are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group];
II. Phosphine compound represented by the following formula (II):

(II)
[Wherein R _{4 to} R ₆ are a cyclohexyl group, a propyl group, an n-butyl group, a t-butyl group, or a phenyl group];
III. Bisoxazoline compound represented by the following formula (III):

(III)
[Wherein R ₇ and R ₈ are a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ₉ and R ₁₀ are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a phenyl group];
IV. Nitrogen-containing aromatic compounds selected from pyridine, 2,2′-bipyridyl, 1,10-phenanthroline or derivatives thereof;
V. Acetic acid derivatives selected from acetic acid, trifluoroacetic acid or derivatives thereof. The ligand is at least one selected from the group consisting of 2,4-pentanedionato, 2,2'-bipyridyl, 3-n-butyl-2,4-pentandionato and acetic acid. 2. A process for producing an aromatic hydroxycarboxylic acid according to 1 . The method for producing an aromatic hydroxycarboxylic acid according to claim 1 or 2 , wherein the ligand is 2,4-pentanedionate. The metal complex according to any one of claims 1 to 3 , wherein the metal complex has Al, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Zr, Mo, Pd, Pb, or Ru as a metal. A method for producing an aromatic hydroxycarboxylic acid. The aromatic hydroxycarboxylic acid according to any one of claims 1 to 4 , wherein the alkali metal salt of the aromatic hydroxy compound is at least one selected from the group consisting of phenol sodium, phenol potassium and 2-naphthol potassium. Production method. The method for producing an aromatic hydroxycarboxylic acid according to any one of claims 1 to 5 , wherein the temperature during the reaction is 20 to 220 ° C.