JP5829577B2 - Method for reducing halogen content in aromatic compounds - Google Patents

Description

  The present invention relates to a method for reducing the halogen content in an aromatic compound.

  Polymers produced from aromatic compounds are used as various chemicals for electronic materials, but when halogens remain in the aromatic compounds or polymers, the performance of the electronic materials is adversely affected. There are many. Accordingly, the amount of residual halogen in the aromatic compound or polymer may be strictly regulated to the ppm or ppb level. In addition, the use of organic materials containing harmful halogens tends to be avoided.

  Conventionally, dehalogenation treatment of an organic halogen compound is known, and a method of removing halogen from an organic halogen compound by mineralizing the halogen (organic halogen) of the organic halogen compound to form an inorganic halogen (ionic halogen) and so on. For example, a method of treating an organic halogen compound with sodium metal (Patent Document 1), a method of treating an organohalogen compound in an alkali hydroxide alcohol solution in the presence of a noble metal catalyst such as palladium (Patent Document 2), and the like are known.

JP 2001-294539 A JP 2007-61108 A

However, although the method described in Patent Document 1 has the merit that it can be dehalogenated under mild conditions, since it uses metallic sodium, the solvent used for the dehalogenation treatment is limited to a non-aqueous solvent. Had problems. There is also a problem that sodium must be decomposed with water after a predetermined dehalogenation treatment. Furthermore, since the method described in Patent Document 2 requires the use of an expensive noble metal catalyst, there is a problem in economy. The methods described in Patent Documents 1 and 2 are unsuitable for removing trace amounts of halogens because it is essential to use expensive reagents and catalysts.
Accordingly, an object of the present invention is to solve the above-described problems of the prior art and to provide a method for reducing the halogen content in an aromatic compound at low cost and in a simple manner.

In order to solve the above-described problems, an aspect of the present invention has the following configuration. That is, in the method for reducing the amount of halogen in an aromatic compound according to one embodiment of the present invention, an organic halogen compound contained in the aromatic compound is reacted with an alkali compound in the presence of a catalyst, and the organic halogen compound has an organic halogen compound. Is a method of reducing the halogen content in the aromatic compound by removing as an inorganic halogen, wherein the catalyst is copper, a copper (I) compound or a mixture thereof, and the alkali compound is ammonia, carbon. A primary or secondary amine having a number of 4 or less or a mixture of ammonia and the amine is used, and the reaction temperature is 100 ° C. or higher and lower than 300 ° C.
In the method for reducing the amount of halogen in the aromatic compound, the alkali compound is preferably ammonia water, an aqueous solution of a primary or secondary amine having 4 or less carbon atoms, or a mixture of aqueous ammonia and an aqueous solution of the amine. .

The aromatic compound may be an aromatic carboxylic acid, a phenol, or a mixture thereof.
Further, the method for reducing the halogen content in the aromatic compound can reduce the halogen content in the aromatic compound to 1 ppm or less.
Furthermore, in the method for reducing the amount of halogen in the aromatic compound, the reaction time may be 2 hours or longer and 30 hours or shorter.

  The method for reducing the halogen content in the aromatic compound according to the present invention can reduce the halogen content in the aromatic compound at low cost and in a simple manner.

Embodiments of a method for reducing the amount of halogen in an aromatic compound according to the present invention will be described in detail below.
Aromatic compounds are used, for example, as raw materials for polymers, and polymers produced from aromatic compounds are used as, for example, chemicals for electronic materials, but when halogen remains in the aromatic compounds or polymers, The performance of the electronic material may be adversely affected. Therefore, it is preferable to remove halogen contained in the aromatic compound.
Since an aromatic compound may contain an organic halogen compound, the aromatic compound is subjected to a dehalogenation treatment to decompose the organic halogen compound in the aromatic compound, and in the aromatic compound. Reduce the halogen (organic halogen) content.

  In the method for reducing the amount of halogen in an aromatic compound according to this embodiment, an organic halogen compound contained in the aromatic compound is reacted with an alkali compound in the presence of a catalyst, and the organic halogen contained in the organic halogen compound is removed as an inorganic halogen. To reduce the halogen content in the aromatic compound, wherein the catalyst is copper, a copper (I) compound or a mixture thereof, and the alkali compound is ammonia, a primary or lower carbon number of 4 or less. It is a secondary amine or a mixture of ammonia and the amine, and the reaction temperature is 100 ° C. or higher and lower than 300 ° C.

The organic halogen compound is dehalogenated by the reaction with the alkali compound, and the halogen is substituted with an OH group (derived from water or the like). Halogen desorbed from the organic halogen compound is inorganic ionized and removed as a salt generated by reacting with, for example, an alkali compound in a subsequent step. As a result, the halogen content in the aromatic compound is reduced, and can be reduced to, for example, 1 ppm or less.
The method for reducing the amount of halogen in the aromatic compound according to this embodiment is inexpensive because an inexpensive copper-based catalyst is used as the catalyst. Ammonia and amines used as alkali compounds are also inexpensive. Furthermore, since ammonia or the amine is used as the alkali compound, a complicated post-treatment as in the case of using metallic sodium is unnecessary, and the dehalogenation treatment is simple.

  Although the kind of aromatic compound is not specifically limited, For example, water-soluble organic compounds, such as aromatic carboxylic acid and phenols, are mention | raise | lifted. Specific examples of the aromatic carboxylic acid include 4,4′-biphenyldicarboxylic acid and 3,4,3 ′, 4′-biphenyltetracarboxylic acid. Specific examples of the phenols include 4,4′- Examples thereof include dihydroxydiphenyl and 4,4′-dihydroxydiphenyl ether. The aromatic compound may be a single type of compound or a mixture of two or more types of compounds.

  Further, the type of the organic halogen compound contained in the aromatic compound is not particularly limited, and examples thereof include halogenated aromatic carboxylic acids and halogenated phenols, and specific examples include: Specific examples of the aromatic compound include the aforementioned aromatic carboxylic acids and phenol halides. The number of halogen atoms contained in the organic halogen compound is not particularly limited, and may be one or more. Further, the type of halogen is not particularly limited, and examples thereof include fluorine, chlorine, bromine and iodine. In addition, in the aromatic compound, 1 type of organic halogen compounds may be contained and 2 or more types of organic halogen compounds may be contained.

Furthermore, although the kind of copper (I) compound used as a catalyst is not specifically limited, For example, copper (I) oxides, such as copper (I) oxide and copper chloride (I), are suitable. . In addition, when using metallic copper (for example, copper powder) as a catalyst, metallic copper can be isolate | separated by filtration etc. from a reaction liquid after a dehalogenation process, and can be reused repeatedly.
In the method for reducing the amount of halogen in the aromatic compound according to this embodiment, a solvent can be used, and the reaction can be performed in the solvent. The type of solvent is not particularly limited. For example, water, alcohols (methanol, ethanol, ethylene glycol, etc.), ethers (tetrahydrofuran, dioxane, etc.), ketones (acetone, methyl ethyl ketone, etc.), fatty acids (acetic acid, etc.) , Propionic acid, etc.), or a mixture of two or more of these. However, water is most preferable in consideration of the decomposition efficiency of organic halogen compounds, economic efficiency, environmental load, and the like.

  In the method for reducing the amount of halogen in the aromatic compound according to this embodiment, ammonia, a primary or secondary amine having 4 or less carbon atoms, or a mixture of ammonia and the amine can be used as the alkali compound. About an amine, you may use 2 or more types of amine together. For example, a plurality of primary amines (may be secondary amines) having different carbon numbers may be used in combination, or primary amines and secondary amines having the same carbon number (may have different carbon numbers) May be used in combination.

Examples of the primary amine having 4 or less carbon atoms include methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, and t-butylamine. Examples of the secondary amine having 4 or less carbon atoms include dimethylamine, diethylamine, di-n-propylamine, diisopropylamine, di-n-butylamine, diisobutylamine, and di-t-butylamine.
The reason why the primary amine and the secondary amine have 4 or less carbon atoms is that the economy (price), availability, and dehalogenation effect are excellent.

The alkali compound is preferably used in the form of an aqueous solution. That is, it is preferable to use aqueous ammonia, an aqueous solution of the amine, or an aqueous solution containing ammonia and the amine as the alkali compound. The ammonia concentration in the ammonia water and the amine concentration in the aqueous amine solution are both preferably 1% by mass to 50% by mass, and more preferably 10% by mass to 30% by mass.
Furthermore, the reaction temperature is preferably 100 ° C. or higher and lower than 300 ° C., more preferably 150 ° C. or higher and 200 ° C. or lower. The reason for setting the reaction temperature within the above range is that dehalogenation hardly proceeds when the reaction temperature is less than 100 ° C., and on the other hand, when the reaction temperature is 300 ° C. or more, decomposition and heaviness of the aromatic compound become remarkable.
The reaction time is preferably 2 hours or longer and 30 hours or shorter, and more preferably 5 hours or longer and 20 hours or shorter. The reason for setting the reaction time in the above-mentioned range is that dehalogenation does not proceed completely in a short time, whereas on the other hand, the decomposition and heaviness of the aromatic compound become remarkable.

The present invention will be described more specifically with reference to the following examples and comparative examples.
Example 1
A SUS autoclave with a capacity of 100 ml was charged with 5 g of 4,4′-dihydroxydiphenyl ether, 0.5 g of copper powder, 0.1 g of copper (I) oxide, and 20 g of ammonia water having a concentration of 28 mass%, and the temperature was raised to 180 ° C. And allowed to react for 20 hours at the same temperature with stirring. The used 4,4′-dihydroxydiphenyl ether contains a trace amount of an organic bromine compound (4,4′-dibromodiphenyl ether), and the content of organic bromine is 135 ppm.
By this reaction, the organic bromine compound in 4,4′-dihydroxydiphenyl ether is decomposed with ammonia, and bromine contained in the organic bromine compound is replaced with an OH group derived from water of ammonia water. Then, bromine desorbed from the organic bromine compound is inorganic ionized and reacts with ammonia to become a salt (ammonium bromide).

  Next, the reaction solution was taken out from the autoclave and acidified with sulfuric acid to liberate 4,4'-dihydroxydiphenyl ether. The liberated 4,4'-dihydroxydiphenyl ether was separated from the reaction solution, desalted according to a conventional method to remove inorganic bromine (salt), and then incinerated. The amount of bromine in the obtained ash was analyzed by ion chromatography, and converted to the content of organic bromine in the released 4,4′-dihydroxydiphenyl ether, which was 663 ppb.

(Example 2)
A SUS autoclave with a capacity of 100 ml was charged with 5 g of 4,4′-biphenyldicarboxylic acid, 0.5 g of copper powder, 0.05 g of copper (I) oxide, and 20 g of ammonia water having a concentration of 28 mass%, and the temperature was raised to 190 ° C. Warmed and allowed to react for 20 hours at the same temperature with stirring. The used 4,4′-biphenyldicarboxylic acid contains a trace amount of an organic bromine compound (4,4′-dibromobiphenyl), and the content of organic bromine is 50 ppm.
By this reaction, the organic bromine compound in 4,4′-biphenyldicarboxylic acid is decomposed with ammonia, and bromine contained in the organic bromine compound is replaced with an OH group derived from water of ammonia water. Then, bromine desorbed from the organic bromine compound is inorganic ionized and reacts with ammonia to become a salt (ammonium bromide).

  Next, the reaction solution was taken out from the autoclave and acidified with sulfuric acid to precipitate 4,4'-biphenyldicarboxylic acid. The precipitated 4,4′-biphenyldicarboxylic acid was separated from the reaction solution, desalted according to a conventional method to remove inorganic bromine (salt), and then ashed. And the amount of bromine in the obtained ash was analyzed by ion chromatography, and converted to the content of organic bromine in the deposited 4,4'-biphenyldicarboxylic acid, it was 443 ppb.

(Example 3)
A SUS autoclave with a capacity of 100 ml was charged with 5 g of 3,4,3 ′, 4′-biphenyltetracarboxylic acid, 0.5 g of copper powder, and 20 g of ammonia water having a concentration of 28 mass%, and the temperature was raised to 190 ° C. The reaction was carried out at the same temperature for 10 hours while stirring. The 3,4,3 ′, 4′-biphenyltetracarboxylic acid used contains a small amount of an organic bromine compound (4-bromophthalic acid), and the content of organic bromine is 16 ppm.
By this reaction, the organic bromine compound in 3,4,3 ′, 4′-biphenyltetracarboxylic acid is decomposed with ammonia, and bromine contained in the organic bromine compound is replaced with an OH group derived from water of ammonia water. . Then, bromine desorbed from the organic bromine compound is inorganic ionized and reacts with ammonia to become a salt (ammonium bromide).

  Next, the reaction solution was taken out from the autoclave and acidified with sulfuric acid to precipitate 3,4,3 ', 4'-biphenyltetracarboxylic acid. Precipitated 3,4,3 ', 4'-biphenyltetracarboxylic acid was separated from the reaction solution, desalted according to a conventional method to remove inorganic bromine (salt), and then ashed. Then, the amount of bromine in the obtained ash was analyzed by ion chromatography and converted to the content of organic bromine in the precipitated 3,4,3 ′, 4′-biphenyltetracarboxylic acid, which was 860 ppb. It was.

Example 4
A SUS autoclave with a capacity of 100 ml was charged with 5 g of 4,4′-dihydroxydiphenyl ether, 0.5 g of copper powder, and 20 g of ammonia water having a concentration of 28% by mass. The temperature was raised to 190 ° C. Reacted for hours. The used 4,4′-dihydroxydiphenyl ether contains a trace amount of an organic bromine compound (4,4′-bromodiphenyl ether), and the content of organic bromine is 135 ppm.
By this reaction, the organic bromine compound in 4,4′-dihydroxydiphenyl ether is decomposed with ammonia, and bromine contained in the organic bromine compound is replaced with an OH group derived from water of ammonia water. Then, bromine desorbed from the organic bromine compound is inorganic ionized and reacts with ammonia to become a salt (ammonium bromide).

  Next, the reaction solution was taken out from the autoclave and acidified with sulfuric acid to liberate 4,4'-dihydroxydiphenyl ether. The liberated 4,4'-dihydroxydiphenyl ether was separated from the reaction solution, desalted according to a conventional method to remove inorganic bromine (salt), and then incinerated. And the amount of bromine in the obtained ash was analyzed by ion chromatography, and converted to the content of organic bromine in the released 4,4'-dihydroxydiphenyl ether, it was 580 ppb.

(Example 5)
A 100 ml SUS autoclave was charged with 5 g of 4,4′-dihydroxydiphenyl ether, 0.5 g of copper powder, and 30 g of a 20% strength by weight methylamine aqueous solution, heated to 180 ° C. and stirred at the same temperature. The reaction was performed for 20 hours. The used 4,4′-dihydroxydiphenyl ether contains a trace amount of an organic bromine compound (4,4′-bromodiphenyl ether), and the content of organic bromine is 135 ppm.
By this reaction, the organic bromine compound in 4,4′-dihydroxydiphenyl ether is decomposed with methylamine, and bromine contained in the organic bromine compound is replaced with OH groups derived from water in the aqueous methylamine solution. Bromine desorbed from the organic bromine compound is inorganic ionized and reacts with methylamine to form a salt (methylamine hydrobromide).

  Next, the reaction solution was taken out from the autoclave and acidified with sulfuric acid to liberate 4,4'-dihydroxydiphenyl ether. The liberated 4,4'-dihydroxydiphenyl ether was separated from the reaction solution, desalted according to a conventional method to remove inorganic bromine (salt), and then incinerated. And the amount of bromine in the obtained ash was analyzed by ion chromatography, and converted to the content of organic bromine in the released 4,4'-dihydroxydiphenyl ether, it was 1 ppm.

(Example 6)
A SUS autoclave with a capacity of 100 ml was charged with 5 g of 4,4′-dihydroxydiphenyl ether, 0.5 g of copper powder, 15 g of an aqueous methylamine solution having a concentration of 40% by mass, and 15 g of ethylene glycol. The reaction was carried out at the same temperature for 20 hours. The used 4,4′-dihydroxydiphenyl ether contains a trace amount of an organic bromine compound (4,4′-bromodiphenyl ether), and the content of organic bromine is 135 ppm.
By this reaction, the organic bromine compound in 4,4′-dihydroxydiphenyl ether is decomposed with methylamine, and bromine contained in the organic bromine compound is replaced with OH groups derived from water in the aqueous methylamine solution. Bromine desorbed from the organic bromine compound is inorganic ionized and reacts with methylamine to form a salt (methylamine hydrobromide).

  Next, the reaction solution was taken out from the autoclave and acidified with sulfuric acid to liberate 4,4'-dihydroxydiphenyl ether. The liberated 4,4'-dihydroxydiphenyl ether was separated from the reaction solution, desalted according to a conventional method to remove inorganic bromine (salt), and then incinerated. The amount of bromine in the obtained ash was analyzed by ion chromatography, and converted to the content of organic bromine in the released 4,4′-dihydroxydiphenyl ether, which was 745 ppb.

(Comparative Example 1)
When the treatment was performed in the same manner as in Example 1 except that copper powder and copper (I) oxide were not used, the content of organic bromine in the released 4,4′-dihydroxydiphenyl ether was calculated. It was 38 ppm.
(Comparative Example 2)
The treatment was performed in the same manner as in Example 1 except that the reaction temperature was 80 ° C., and the content of organic bromine in the released 4,4′-dihydroxydiphenyl ether was calculated to be 118 ppm.

Claims (4)

By reacting an organic halogen compound contained in the aromatic compound with an alkali compound in the presence of a catalyst, and removing the organic halogen contained in the organic halogen compound as an inorganic halogen, the halogen content in the aromatic compound is reduced. The catalyst is copper, a copper (I) compound or a mixture thereof, and the alkali compound is ammonia water , an aqueous solution of a primary or secondary amine having 4 or less carbon atoms, or ammonia water and the amine. A method for reducing the amount of halogen in an aromatic compound, wherein the reaction temperature is 100 ° C. or higher and lower than 300 ° C. The method for reducing the amount of halogen in an aromatic compound according to claim 1, wherein the aromatic compound is an aromatic carboxylic acid, a phenol, or a mixture thereof. The method for reducing the halogen content in an aromatic compound according to claim 1 or 2 , wherein the halogen content in the aromatic compound is reduced to 1 ppm or less. The method for reducing the amount of halogen in an aromatic compound according to any one of claims 1 to 3 , wherein the reaction time is 2 hours or more and 30 hours or less.