JPH083105A - Production of naphthalenedicarboxylic acid diamine salt - Google Patents

Abstract

PURPOSE:To obtain the subject high-purity compound by reaction of a crude naphthalenedicarboxylic acid with a 6-20C aliphatic dlamine. CONSTITUTION:In producing this compound by reaction of a crude naphthalenedicarboxylic acid with a 6-20C aliphatic diamine, it is characteristic that the naphthalenedicarboxylic acid is reacted with virtually 0.9-3 molar times of the diamine at 50-200 deg.C in the presence of such an amount of water as to be enough to be perfectly soluble for the naphthalenedicarboxylic acid diamine salt formed and the resultant reaction liquor is filtered at such a temperature as not to deposit the salt to remove insolubles and the resultant aqueous solution containing the salt is cooled to 40 deg.C or lower to deposit the objective salt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for efficiently producing a highly pure naphthalenedicarboxylic acid diamine salt from crude naphthalenedicarboxylic acid by a simple process.
The naphthalene dicarboxylic acid diamine salt is useful as a raw material for polyamide resin.

[0002]

BACKGROUND OF THE INVENTION Naphthalenedicarboxylic acid is generally produced by subjecting a naphthalene compound corresponding to a desired naphthalene dicarboxylic acid such as an alkyl compound, an acyl compound or an aldehyde compound to gas phase oxidation or liquid phase oxidation. The residue and organic impurities having an alkyl group or an aldehyde group are contained on one side of the naphthalene ring. Therefore, it is necessary to remove impurities to obtain high-purity naphthalene dicarboxylic acid, but since naphthalene dicarboxylic acid generally has poor solubility in a solvent, purification by recrystallization is difficult. Further, since it has substantially no melting point, purification by distillation or sublimation is difficult.

In order to obtain high-purity naphthalenedicarboxylic acid, it is common to use crude naphthalenedicarboxylic acid as a lower alkyl ester such as dimethyl ester after purification such as distillation or recrystallization, followed by hydrolysis with alkali or the like. is there. However, in this method, the particles of naphthalenedicarboxylic acid deposited on the product tend to contain alkali metal in the product and are very fine and difficult to filter, and further produce a large amount of acid, alkaline wastewater, etc. The method is hard to say. Thus, a method for efficiently producing high-purity naphthalene dicarboxylic acid has not been known so far, and a new method is desired to appear.

In Japanese Examined Patent Publication No. Sho 48-23200, 1,
The method of producing a salt of 5-naphthalenedicarboxylic acid and hexamethylenediamine using water as a solvent is mentioned, but the purity of naphthalenedicarboxylic acid as a raw material is not mentioned. Also, EP Patent Publication No. 04117.
No. 90, 2,6-naphthalenedicarboxylic acid and 1,6
-Proposed is a method of forming a salt with hexamethylenediamine in water as a solvent and precipitating crystals under specific conditions. However, the purity of the raw material naphthalenedicarboxylic acid and the product 2,6-naphthalenedicarboxylic acid hexa No mention is made of the purity of the methylenediamine salt.

[0005]

As described above, in the situation where it is difficult to efficiently produce high-purity naphthalene dicarboxylic acid, the method using a high-purity naphthalene dicarboxylic acid as a raw material is a practical naphthalene dicarboxylic acid. It is difficult to say that it is a method for producing a diamine salt. The purpose of the present invention is to
An object of the present invention is to provide a method for efficiently producing a naphthalene dicarboxylic acid diamine salt, which is useful as a raw material for a polyamide resin or the like, from a crude naphthalene dicarboxylic acid containing impurities as a raw material.

[0006]

[Means for Solving the Problems] The present inventors have made high purity by reacting and treating a crude naphthalene dicarboxylic acid having a specific purity and an aliphatic diamine having 6 to 20 carbon atoms under specific conditions. It was found that the naphthalene dicarboxylic acid diamine salt can be obtained, and the above problems were solved.

That is, according to the present invention, when naphthalenedicarboxylic acid having a purity of 90% by weight or more is reacted with an aliphatic diamine having 6 to 20 carbon atoms to produce a naphthalenedicarboxylic acid diamine salt, naphthalenedicarboxylic acid and
0.9 to 3 times the molar amount of an aliphatic diamine with respect to naphthalenedicarboxylic acid is reacted at a temperature of 50 to 200 ° C. in the presence of water sufficient to completely dissolve the resulting naphthalenedicarboxylic acid diamine salt, After removing the insoluble matter by filtration at a temperature at which the produced crude naphthalenedicarboxylic acid diamine salt does not precipitate, the aqueous solution containing the naphthalenedicarboxylic acid diamine salt is cooled to 40 ° C. or lower to crystallize the naphthalenedicarboxylic acid diamine salt. The present invention relates to a method for producing a naphthalenedicarboxylic acid diamine salt having a purity of 99% or more, which is characterized by being purified. The present invention will be described in detail below.

As the naphthalenedicarboxylic acid as a raw material of the naphthalenedicarboxylic acid diamine salt of the present invention, it can be used for all isomers, but preferably 1,5-
These include naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, and 2,6-naphthalenedicarboxylic acid, and one of these may be used, or a mixture of two or more isomers may be used. Particularly preferred is 2,6-naphthalenedicarboxylic acid.

The naphthalenedicarboxylic acid used as the raw material for the production of the present invention contains 90% by weight or more of naphthalenedicarboxylic acid, preferably 90 to 98% by weight.
If the purity of the naphthalenedicarboxylic acid used as a raw material is less than 90%, it is difficult to efficiently obtain the desired high-purity naphthalenedicarboxylic acid diamine salt even if the production method of the present invention is adopted.

Further, the naphthalenedicarboxylic acid used as a raw material usually contains cobalt and manganese, which were used as an oxidation catalyst when oxidizing naphthalenedicarboxylic acid to synthesize them, as impurities. Those of 10,000 ppm or less, preferably 1000
In the production method of the present invention, those containing 1 to 10,000 ppm can efficiently remove these impurities in the purification step of the naphthalenedicarboxylic acid diamine salt. When the total amount of cobalt and manganese exceeds 10,000 ppm, it becomes difficult to efficiently obtain the desired high-purity diamine salt of naphthalenedicarboxylic acid.

Examples of the aliphatic diamine having 6 to 20 carbon atoms for use in the present invention include hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,2,4-. Examples include trimethylhexamethylenediamine and 2,4,4-trimethylhexamethylenediamine. The most preferred aliphatic diamine used in the present invention is hexamethylene diamine.

The step of reacting naphthalenedicarboxylic acid with an aliphatic diamine in the present invention will be described.
The molar ratio of the aliphatic diamine to the naphthalenedicarboxylic acid is suitably 0.9 to 3 times. The molar ratio is 0.9
When it is smaller than the above range, the yield of the desired product naphthalenedicarboxylic acid diamine salt is low, which is not preferable. If the molar ratio is greater than 3, the economy is poor. The preferred molar ratio is 1-1.
5, particularly preferably 1 to 1.1.

In the present invention, it is important that the naphthalenedicarboxylic acid diamine salt produced by reacting naphthalenedicarboxylic acid with an aliphatic diamine is completely dissolved in water as a solvent. In the present invention, water is essential as a solvent, but an organic solvent compatible with water may be used as long as the object of the present invention is not impaired. Examples of those organic solvents are methanol, ethanol, tetrahydrofuran, acetone, dimethylacetamide, dimethylformamide, N-methylpyrrolidone, dimethylsulfoxide and the like. The solubility of naphthalenedicarboxylic acid diamine salt in water generally has a large temperature dependency. FIG. 1 shows the solubility in water in the case of a salt of 2,6-naphthalenedicarboxylic acid and hexamethylenediamine (hereinafter abbreviated as 2,6-6N salt). Appropriate reaction temperature conditions can be found from such a solubility diagram.

The reaction temperature for producing the naphthalenedicarboxylic acid diamine salt in the present invention is 50 to 200 ° C. in order to completely dissolve the naphthalenedicarboxylic acid diamine salt in water.
Preferably 70 to 150 ° C., particularly preferably 80 to 12
0 ° C. When the reaction temperature is 50 ° C or lower, the solubility of the naphthalenedicarboxylic acid diamine salt in water is low, and the target product cannot be efficiently produced. On the other hand, the above 2
Above 00 ° C, a reactor capable of withstanding high pressure must be used, which is not economical. The amount of water sufficient to completely dissolve the naphthalenedicarboxylic acid diamine salt under the above temperature conditions can be known by determining the solubility of the corresponding naphthalenedicarboxylic acid diamine salt in water as shown in FIG. By using an appropriate amount of water as a solvent, since the target product naphthalene dicarboxylic acid diamine salt is the main solute component and other impurities are not dissolved, depending on the purity of the raw material naphthalene dicarboxylic acid slurry, or It becomes cloudy.

After synthesizing the naphthalenedicarboxylic acid diamine salt, the insoluble matter is removed by filtering the aqueous solution in which the naphthalenedicarboxylic acid diamine salt is dissolved. In this step, it is important to maintain the temperature at which the dissolved naphthalenedicarboxylic acid diamine salt does not precipitate. Under such temperature conditions, pressure filtration, vacuum filtration using filter paper or filter cloth,
Various conventionally known filtration methods such as centrifugation can be applied. It is also possible to sufficiently precipitate the insoluble matter and separate the insoluble matter by decantation.

It is one of the preferred embodiments of the present invention to remove impurities such as metals in the solution by treating with an adsorbent during the step of separating the insoluble matter or after removing the insoluble matter. Types of adsorbents include activated carbon, activated clay,
It is at least one selected from activated alumina and zeolite. One of these adsorbents may be used alone, or a plurality of types of adsorbents may be used in combination or may be used in stages. A particularly preferred adsorbent is activated carbon. The adsorbent may be used by dispersing a powdery one in the solution, or by providing a layer of the adsorbent and allowing the solution to pass therethrough. The treatment with the adsorbent is effective for removing metals such as cobalt and manganese and improving the color tone of the resulting naphthalenedicarboxylic acid diamine salt.

After removing the insolubles by filtration, the aqueous solution containing the naphthalenedicarboxylic acid diamine salt is cooled to 40 ° C. or lower to precipitate crystals of the naphthalenedicarboxylic acid diamine salt. There is no particular limitation on the cooling rate from the state in which the naphthalene dicarboxylic acid diamine salt is completely dissolved to 40 ° C. or less. Since the solubility of the solute in water is lowered at this stage, it is possible to accelerate the precipitation of crystals of the naphthalenedicarboxylic acid diamine salt by adding an organic solvent which is a poor solvent for the naphthalenedicarboxylic acid diamine salt. Examples of suitable organic solvents are methanol, ethanol, tetrahydrofuran, acetone, N, N-dimethylacetamide, N, N-dimethylformamide, N-methylpyrrolidone, dimethylsulfoxide and the like.

The precipitated crystals of naphthalenedicarboxylic acid diamine salt can be easily separated by a conventionally known method such as filtration, centrifugation or decantation. The separated crystals of the diamine salt of naphthalenedicarboxylic acid may be dried as they are, or if necessary, washed with cold water or a solvent such as methanol.

According to the manufacturing method of the present invention, the purity is 99% or more, and the total amount of cobalt and manganese is 1000 p.
It is possible to easily obtain a naphthalene dicarboxylic acid diamine salt of pm or less. Further, when a high-purity naphthalenedicarboxylic acid diamine salt is required, the obtained crystals of the naphthalenedicarboxylic acid diamine salt are dissolved in a suitable solvent such as water, and if necessary after adsorption treatment with activated carbon or the like. Further, by performing so-called recrystallization in which insoluble matters are removed and then cooled to take out crystals, a naphthalene dicarboxylic acid diamine salt of higher purity can be obtained.

The naphthalenedicarboxylic acid diamine salt obtained in the present invention is useful as a raw material for polyamide resins and the like, and can be further treated with an acid to liberate the naphthalenedicarboxylic acid to give a highly pure naphthalenedicarboxylic acid. it can.

[0021]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited to the following examples. The raw material naphthalene dicarboxylic acid and the product naphthalene dicarboxylic acid diamine salt were analyzed by the following methods.

The purity was measured by liquid chromatography using diphenyl as an internal standard substance. Column: ODS-2 4.6 ID × 250 mm, column temperature: 40 ° C. Developing solution, and sample dissolving solution: tetrahydrofuran / water / acetic acid 500/500/3 (volume ratio) Detector: UV254.7 nm

Metal Content The samples were ashed and Mn and Co were measured by atomic absorption spectrometry. Measuring device: Seiko Electronics Co., Ltd. SAS760 Frame: Acetylene / Air frame

Melting point It was determined from the endothermic peak due to melting from differential thermal analysis (DTA). Measuring device: Seiko Electronics Co., Ltd. TG / DTA20
0 Temperature rising rate: 10 ° C / min

The color tone color difference meter was measured using a Σ-80 type manufactured by Nippon Denshoku Co., Ltd.

Example 1 Containing 97% by weight of 2,6-naphthalenedicarboxylic acid,
And 660ppm of cobalt and 2600pp of manganese
9.30 g of crude naphthalene dicarboxylic acid containing m
(0.043 mol) and hexamethylenediamine (5.00 g, 0.043 mol) at 90 ° C. in water (350 m)
1 and dissolved. This solution was filtered while hot, and the obtained filtrate was cooled to 10 ° C. The precipitated crystals were separated by filtration and dried. The analysis results of the obtained 2,6-6N salt are summarized in Table 1. A 2,6-6N salt having a purity of 99% or more and a total amount of cobalt and manganese of 1000 ppm or less could be easily obtained.

Example 2 Containing 97% by weight of 2,6-naphthalenedicarboxylic acid,
And 660ppm of cobalt and 2600pp of manganese
9.30 g of crude naphthalene dicarboxylic acid containing m
(0.043 mol) and hexamethylenediamine (5.00 g, 0.043 mol) at 90 ° C. in water (350 m)
1 and dissolved. 0.14 g of activated carbon was added to this solution and stirring was continued for 1 hour. This solution was filtered while hot, and the obtained filtrate was cooled to 10 ° C. The precipitated crystals were separated by filtration and dried. The analysis results of the obtained 2,6-6N salt are summarized in Table 1. The treatment with activated carbon was effective in removing metals such as cobalt and manganese and improving the color tone of the resulting 2,6-6N salt.

Example 3 The same operation as in Example 2 was performed except that the amount of activated carbon added was 1.43 g. The analysis results of the obtained 2,6-6N salt are summarized in Table 1. Increasing the amount of activated carbon from Example 2 increased the effect of removing metals such as cobalt and manganese and the effect of improving the color tone of the resulting 2,6-6 salt.

Example 4 Containing 92% by weight of 2,6-naphthalenedicarboxylic acid,
And 3700ppm of cobalt and 4500p of manganese
The same operation as in Example 1 was performed except that the crude naphthalene dicarboxylic acid containing pm was used. 2,6-obtained
The results of the 6N salt analysis are summarized in Table 1. Purity 99% or more and total amount of cobalt and manganese is 1000p
It was possible to easily obtain a 2,6-6N salt having a pm or less.

Example 5 Containing 92% by weight of 2,6-naphthalenedicarboxylic acid,
And 3700ppm of cobalt and 4500p of manganese
The same operation as in Example 2 was performed except that the crude naphthalene dicarboxylic acid containing pm was used. 2,6-obtained
The results of the 6N salt analysis are summarized in Table 1. The treatment with activated carbon was effective in removing metals such as cobalt and manganese and improving the color tone of the resulting 2,6-6N salt.

Example 6 The same operation as in Example 5 was performed except that the amount of activated carbon added was 1.43 g. The analysis results of the obtained 2,6-6N salt are summarized in Table 1. By increasing the amount of activated carbon from Example 5, the effect of removing metals such as cobalt and manganese and the effect of improving the color tone of the resulting 2,6-6N salt were increased.

Comparative Example 1 88% by weight of 2,6-naphthalenedicarboxylic acid was contained,
And 5500ppm of cobalt and 7500p of manganese
The same operation as in Example 1 was performed except that the crude naphthalene dicarboxylic acid containing pm was used. 2,6-obtained
The results of the 6N salt analysis are summarized in Table 1. When the purity of naphthalene dicarboxylic acid used as a raw material is less than 90% and the total amount of cobalt and manganese is 10,000 ppm or more,
The desired highly pure 2,6-6N salt could not be obtained.

Table 1 Purity Metal Content (ppm) Color Tone Melting Point (%) Co Mn Lab (° C.) Example 1 99-100 4 36 85.5 3.1 11.4 281 Example 2 99-100 10 15 87.7 3.2 6.2 280 Example 3 99-100 3 9 90.5 0.9 3.4 280 Example 4 99-100 170 620 59.7 9.2 20.3 280 Example 5 99-100 78 220 72.5 5.5 15.8 280 Example 6 99-100 36 33 83.6 2.7 12.1 280 Comparative Example 1 97 330 1200 44.8 13.2 32.0 280

[0034]

Industrial Applicability By using the method of the present invention, a high-purity naphthalenedicarboxylic acid diamine salt can be efficiently obtained from a crude naphthalenedicarboxylic acid having a specific purity as a raw material in a simple process.

[Brief description of drawings]

FIG. 1 is a water solubility diagram of a salt of 2,6-naphthalenedicarboxylic acid and hexamethylenediamine.

Claims (4)

[Claims] 1. When producing a naphthalenedicarboxylic acid diamine salt by reacting a naphthalenedicarboxylic acid having a purity of 90% by weight or more with an aliphatic diamine having 6 to 20 carbon atoms, naphthalenedicarboxylic acid and naphthalenedicarboxylic acid are converted into In contrast, 0.9 to 3 times the molar amount of aliphatic diamine
The insoluble matter is reacted at a temperature of 0 to 200 ° C. in the presence of water sufficient to completely dissolve the produced naphthalenedicarboxylic acid diamine salt, and filtered at a temperature at which the produced crude naphthalenedicarboxylic acid diamine salt does not precipitate. And removing the naphthalenedicarboxylic acid diamine salt by cooling the aqueous solution containing the naphthalenedicarboxylic acid diamine salt to 40 ° C. or lower to crystallize the naphthalenedicarboxylic acid diamine salt for purification. Method for producing salt. 2. A naphthalenedicarboxylic acid having a purity of 90% by weight or more as impurities, and cobalt and manganese in total of 10,000 ppm or less, and the total concentration of cobalt and manganese in the obtained naphthalenedicarboxylic acid diamine salt is 1000 ppm or less. Item 2. A method for producing a naphthalenedicarboxylic acid diamine salt according to Item 1. 3. An aqueous solution containing a naphthalenedicarboxylic acid diamine salt is treated with at least one adsorbent selected from activated carbon, activated clay, activated carbon and na at a temperature at which the naphthalenedicarboxylic acid diamine salt does not precipitate. The method for producing the naphthalenedicarboxylic acid diamine salt according to claim 1 or 2. 4. A method for producing a naphthalenedicarboxylic acid diamine salt according to claim 1, 2 or 3, wherein the naphthalenedicarboxylic acid is 2,6-naphthalenedicarboxylic acid and the aliphatic diamine is hexamethylenediamine. .