JP2015010036A - Method for decomposing aromatic halide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple method for decomposing an aromatic halide contained in an aromatic compound.SOLUTION: An aromatic halide contained in an aromatic compound is reacted with a hydrogen gas in the presence of a noble metal catalyst in an aqueous caustic alkali solution to remove an organic halogen of the aromatic halide as an inorganic halogen, thereby reducing the halogen content in the aromatic compound to 1 ppm or less. The aromatic compound is an aromatic carboxylic acid, a phenol, or a mixture thereof, and the aromatic halide is a halogenated aromatic carboxylic acid, a halogenated phenol, or a mixture thereof.

Description

  The present invention relates to a method for decomposing an aromatic halide contained 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 (see, for example, Patent Document 1), a method of treating in an alcohol solution of an alkali hydroxide in the presence of a noble metal catalyst such as palladium (see, for example, Patent Document 2), etc. It has been 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 after the predetermined dehalogenation treatment, a post-treatment for decomposing sodium with water or the like must be performed.
Furthermore, since the method described in Patent Document 2 uses a mixed solution of 2-propanol and methanol as a reaction solvent, the mixed solution must be removed after the dehalogenation treatment, and a waste solution containing an organic solvent is removed. There was a problem that post-processing was also required.

Thus, the conventional dehalogenation treatment of an organic halogen compound is a simple treatment method because it is necessary to post-treat reagents such as sodium and organic solvents after the dehalogenation treatment. There wasn't.
Then, this invention makes it a subject to solve the trouble which the above prior arts have, and to provide the simple method of decomposing | disassembling an aromatic halide.

In order to solve the above-described problems, an aspect of the present invention has the following configuration. That is, the method for decomposing an aromatic halide according to one embodiment of the present invention comprises reacting an aromatic halide contained in an aromatic compound with hydrogen gas in a caustic aqueous solution in the presence of a noble metal catalyst. And
In this aromatic halide decomposition method, the aromatic compound may be an aromatic carboxylic acid, a phenol, or a mixture thereof. The aromatic halide may be a halogenated aromatic carboxylic acid, a halogenated phenol, or a mixture thereof.
Furthermore, this aromatic halide decomposition method can reduce the halogen content in the aromatic compound to 1 ppm or less.

  The method for decomposing an aromatic halide of the present invention can easily decompose an aromatic halide.

An embodiment of the aromatic halide decomposition method 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 aromatic halide, the aromatic compound is subjected to dehalogenation treatment to decompose the aromatic halide in the aromatic compound, and the aromatic compound Reduce the content of halogen (organic halogen) in it.
In the aromatic halide decomposition method according to the present embodiment, the aromatic halide contained in the aromatic compound is reacted with hydrogen gas in the presence of a noble metal catalyst in a caustic aqueous solution, and the aromatic halide has. In this method, the halogen content in the aromatic compound is reduced by removing the organic halogen as an inorganic halogen.

  Aromatic halides react with hydrogen gas by catalysis to replace halogens with hydrogen atoms, and aromatic halide dehalogenates (aromatic halides with halogens replaced with hydrogen atoms) and halogenated Hydrogen is produced. The produced hydrogen halide reacts with caustic in the caustic aqueous solution to form a salt, and is removed as this salt. As a result, the halogen content in the aromatic compound is reduced, and can be reduced to, for example, 1 ppm or less.

  The aromatic halide decomposition method according to this embodiment does not require the use of an organic solvent as a reaction solvent, and therefore does not require the recovery of the organic solvent or the post-treatment of the waste liquid containing the organic solvent. Further, since a caustic aqueous solution is used for the reaction, a complicated post-treatment as in the case of using metallic sodium is unnecessary. Therefore, the method for decomposing an aromatic halide according to this embodiment is a method capable of easily decomposing an aromatic halide.

  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.

  The type of aromatic halide contained in the aromatic compound is not particularly limited, and examples thereof include halogenated aromatic carboxylic acids and halogenated phenols. 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 aromatic halide 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, one type of aromatic halide may be contained, or two or more types of aromatic halides may be contained.

  Furthermore, the kind of the noble metal catalyst is not particularly limited, and for example, a support in which at least one kind of noble metal such as palladium, platinum, rhodium, ruthenium, nickel, etc. is supported on a support can be used. As the carrier, metal oxides such as silica and alumina, and activated carbon can be used. The supporting rate of the noble metal on the carrier is preferably 0.1% by mass or more and 20% by mass or less, and more preferably 1% by mass or more and 10% by mass or less. The amount of the noble metal catalyst used is not particularly limited, but is preferably 0.01% by mass or more and 10% by mass or less with respect to the aromatic compound.

  Furthermore, the type of the caustic aqueous solution is not particularly limited as long as it is an aqueous solution of a caustic alkali compound. Specific examples of the caustic alkali compound include lithium hydroxide, sodium hydroxide, potassium hydroxide, and rubidium hydroxide. And alkali metal hydroxides such as cesium hydroxide and alkaline earth metal hydroxides such as beryllium hydroxide, magnesium hydroxide, calcium hydroxide, strontium hydroxide, and barium hydroxide.

However, considering its economic efficiency, sodium hydroxide, potassium hydroxide, or a mixture thereof is preferable. When a mixture of sodium hydroxide and potassium hydroxide is used, the mixing ratio can be arbitrarily set.
The concentration of the caustic aqueous solution is preferably 1% by mass or more and 50% by mass or less, and more preferably 5% by mass or more and 20% by mass or less.

  Moreover, you may use together an organic solvent with water as a solvent of caustic aqueous solution. The type of the organic solvent is not particularly limited. For example, alcohols (methanol, ethanol, ethylene glycol, etc.), ethers (tetrahydrofuran, dioxane, etc.), ketones (acetone, methyl ethyl ketone, etc.), fatty acids (acetic acid, Propionic acid, etc.), or a mixture of two or more of these. However, in consideration of the efficiency of decomposition of the aromatic halide, economy, environmental burden, etc., it is most preferable to use only water as the solvent of the caustic aqueous solution.

Furthermore, the pressure of hydrogen gas is preferably 0.1 MPa or more and 5 MPa or less, and more preferably 0.3 MPa or more and 2 MPa or less.
Furthermore, as the reaction temperature, an arbitrary temperature can be selected within the range of 20 ° C. or higher and 200 ° C. or lower, but 50 ° C. or higher and 150 ° C. or lower is more preferable.
Furthermore, the reaction time is preferably 1 hour or longer and 30 hours or shorter, and more preferably 5 hours or longer and 20 hours or shorter.

The present invention will be described more specifically with reference to the following examples and comparative examples.
Example 1
To a 100 ml SUS autoclave was charged 5 g of 4,4′-dihydroxydiphenyl ether, 0.13 g of 5 mass% palladium carbon (containing 50 mass% water), and 39.6 g of an aqueous sodium hydroxide solution having a concentration of 10 mass%. Nitrogen substitution and hydrogen substitution in the autoclave were performed. And after pressurizing with hydrogen gas 0.5MPa, it heated up at 150 degreeC and made it react at the same temperature for 5 hours.

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 167 ppm.
By this reaction, the organic bromine compound in 4,4′-dihydroxydiphenyl ether reacts with hydrogen gas to be decomposed, and the bromine contained in the organic bromine compound is replaced with a hydrogen atom. Bromine desorbed from the organic bromine compound is inorganic ionized and reacts with sodium hydroxide to form a salt (sodium bromide).

  Next, the reaction solution was taken out from the autoclave, palladium carbon was removed from the reaction solution, and the filtrate was 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, it was 771 ppb.

(Example 2)
In a 100 ml SUS autoclave, 5 g of 3,4,3 ′, 4′-biphenyltetracarboxylic acid, 0.13 g of 5% by mass palladium carbon (containing 50% by mass water), and 7.5% by mass potassium hydroxide After charging 68.0 g of the aqueous solution, nitrogen substitution and hydrogen substitution in the autoclave were performed. And after pressurizing with hydrogen gas 0.5MPa, it heated up at 150 degreeC and made it react at the same temperature for 5 hours.

The 3,4,3 ′, 4′-biphenyltetracarboxylic acid used contained a trace amount of an organic chlorine compound (4-chlorophthalic acid), and the content of organic chlorine was 31 ppm.
By this reaction, the organic chlorine compound in 3,4,3 ′, 4′-biphenyltetracarboxylic acid reacts with hydrogen gas to be decomposed, and the chlorine contained in the organic chlorine compound is replaced with a hydrogen atom. Chlorine desorbed from the organic chlorine compound is inorganic ionized and reacts with potassium hydroxide to form a salt (potassium chloride).

  Next, the reaction solution was taken out from the autoclave, palladium carbon was filtered off from the reaction solution, and the filtrate was acidified with sulfuric acid to liberate 3,4,3 ', 4'-biphenyltetracarboxylic acid. The liberated 3,4,3 ′, 4′-biphenyltetracarboxylic acid was separated from the reaction solution, desalted according to a conventional method to remove inorganic chlorine (salt), and then subjected to ashing. The amount of chlorine in the obtained ash was analyzed by ion chromatography, and converted to the content of organic chlorine in the released 3,4,3 ′, 4′-biphenyltetracarboxylic acid, which was 326 ppb. It was.

Example 3
After charging a 100 ml SUS autoclave with 5 g of 4,4′-biphenyldicarboxylic acid, 0.13 g of 5 mass% palladium carbon (containing 50 mass% water), and 49.6 g of an aqueous sodium hydroxide solution having a concentration of 10 mass%. Then, nitrogen substitution and hydrogen substitution in the autoclave were performed. And after pressurizing with hydrogen gas 0.5MPa, it heated up at 150 degreeC and made it react at the same temperature for 5 hours.

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 73 ppm.
By this reaction, the organic bromine compound in 4,4′-biphenyldicarboxylic acid reacts with hydrogen gas to be decomposed, and the bromine of the organic bromine compound is replaced with a hydrogen atom. Bromine desorbed from the organic bromine compound is inorganic ionized and reacts with sodium hydroxide to form a salt (sodium bromide).

  Next, the reaction solution was taken out from the autoclave, palladium carbon was filtered off from the reaction solution, and the filtrate was acidified with sulfuric acid to liberate 4,4'-biphenyldicarboxylic acid. The liberated 4,4'-biphenyldicarboxylic acid 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′-biphenyldicarboxylic acid, which was 693 ppb.

Example 4
The treatment was performed in the same manner as in Example 1 except that the reaction time was 120 ° C. and the reaction time was 10 hours, and the content of organic bromine in the released 4,4′-dihydroxydiphenyl ether was calculated. 736 ppb.
(Example 5)
The treatment was performed in the same manner as in Example 1 except that the hydrogen gas pressure was 1 MPa, and the content of organic bromine in the released 4,4′-dihydroxydiphenyl ether was calculated to be 529 ppb. .

(Comparative Example 1)
Except that the sodium hydroxide aqueous solution having a concentration of 10% by mass was changed to water, the treatment was performed in the same manner as in Example 1, and the content of organic bromine in the released 4,4′-dihydroxydiphenyl ether was calculated. However, it was 132 ppm.
(Comparative Example 2)
Except that 5 mass% palladium carbon was not used, the treatment was performed in the same manner as in Example 1, and the content of organic bromine in the released 4,4′-dihydroxydiphenyl ether was calculated to be 156 ppm. .

Claims (4)

  A method for decomposing an aromatic halide, comprising reacting an aromatic halide contained in an aromatic compound with hydrogen gas in a caustic aqueous solution in the presence of a noble metal catalyst.   The method for decomposing an aromatic halide according to claim 1, wherein the aromatic compound is an aromatic carboxylic acid, a phenol, or a mixture thereof.   The method for decomposing an aromatic halide according to claim 1 or 2, wherein the aromatic halide is a halogenated aromatic carboxylic acid, a halogenated phenol, or a mixture thereof.   The method for decomposing an aromatic halide according to any one of claims 1 to 3, wherein the halogen content in the aromatic compound is reduced to 1 ppm or less.