KR100471112B1 - A refining process of 2,6-Naphtalene Dicarboxylic Acid using a microorganism - Google Patents

Abstract

The present invention relates to crude naphthalene dicarboxylic acid produced by oxidizing 2,6-dimethylnaphthalene by removing 2-formyl-6-naphthoic acid, which is contained as an impurity, using microorganisms to remove 2,6-naphthalene dicarboxylic acid. It is about how to increase the purity. In the purification of crude naphthalenedicarboxylic acid using Bacillus sp. F-3 isolated from soil, glucose was added as a carbon source to the reaction solution, and the pH of the reaction solution was adjusted to 2-formyl-6-. The rate of reduction of naphthoic acid is increased, so that the purification reaction can proceed efficiently. Also, the purification of the bacteria can be continued to recover the cells.

Description

A refining process of 2,6-naphtalene dicarboxylic acid using a microorganism

The present invention provides impurities using microorganisms from crude naphthalene dicarboxylic acid (hereinafter referred to as CNDA) produced by oxidizing 2,6-dimethyl naphthalene (hereinafter referred to as 2,6-DMN). Purity of 2,6-Naphthalene Dicarboxylic Acid (NDA) by removing Phosphorus 2-Formyl-6-Naphthoic Acid (FNA) It is about a method.

The present invention also relates to a method for purifying NDA which can reduce FNA at a rapid rate by adding a carbon source to the reaction solution and adjusting the pH of the reaction solution.

Diesters of naphthalene dicarboxylic acids are useful for preparing various polymeric materials such as polyesters and polyamides.

One example of a particularly useful diester is dimethyl-2,6-naphthalene decarboxylate (NDC).

NDC can be condensed with ethylene glycol to produce poly (ethylene-2,6-naphthalene) (Poly (Ethylene-2,6-Naphthalene); hereinafter PEN), a high-performance polyester material.

Fibers and films made from PEN have higher strength and better thermal properties than poly (ethylene terephthalate) (PET), so PEN is a very good material for making commercial products such as magnetic recording tapes and thin films for electronic component manufacturing. to be.

PEN is also useful for making food containers, especially food containers for high temperature fillings, because of their excellent resistance to gas diffusion, particularly carbon dioxide, oxygen and water vapor.

It can also be used to make reinforcing fibers useful for making tire cords.

Currently, NDC produces CNDA by oxidizing 2,6-DMN and then esterifying it, as shown in FIG. 1.

Currently, NDC is used as a main raw material when synthesizing PEN, but there are some problems compared to using NDA as a raw material.

Firstly, water is produced during NDA condensation reaction, whereas NDC generates methanol as a by-product, and there is a risk of explosion. Second, since pure NDC is produced after esterification of NDA and then purification process, it is one step compared to NDA. Thirdly, if there is a need for further processing, and thirdly if you have an existing PET production facility, the use of NDC is not appropriate to use the existing facility.

Despite the disadvantages of NDC, the reason why NDC is used instead of NDA in PEN production is that it has not yet produced a purified NDA having the purity necessary for polymerization.

Oxidation of DMN generates CNDA containing various impurities such as FNA, 2-naphthoic acid, trimellitic acid, and it is particularly difficult to remove FNA.

The presence of this FNA causes the polymerization to stop in the middle, adversely affecting the physical properties of the polymer.

In order to remove FNA present in CNDA or to purify NDA, recrystallization, oxidation process is performed once more, NDA is prepared by NDC using methanol and then hydrated to produce NDA or purified NDA by hydrogenation process The method of preparing the same and the like have been studied.

In addition, various purification methods such as solvent treatment, melting crystals, high pressure crystals, and supercritical extraction have been used, but have not yet produced NDAs with satisfactory purity.

In addition, if the purity is increased, the yield is very difficult to apply to actual production.

Accordingly, the present invention has been made to solve the problems related to NDA purification as described above, and provides a novel method for purifying NDA by selectively removing FNA contained in CNDA by a biological method using microorganisms. I put it.

Another object of the present invention is to provide a method for purifying NDA, which greatly increases the purification efficiency by adding a carbon source to the purification reaction solution and adjusting the pH.

These objects, features and advantages of the present invention will be more readily understood by reference to the accompanying drawings and the following detailed description.

In addition, this embodiment is only illustrative for the purpose of understanding and is not intended to limit the present invention.

The present invention relates to a method for purifying NDA with high purity by removing FNA which is an impurity contained in CNDA by a microbial strain isolated from soil.

In particular, the present invention relates to a method of significantly increasing the purification efficiency by adding a carbon source to the reaction solution and adjusting the pH of the reaction solution.

The microorganism used in the present invention is Bacillus sp. F-3, which was deposited with the accession number KCTC-10335BP (September 10, 2002) to the Genetic Bank of Korea Biotechnology Institute, an international depository.

Bacillus F-3 can be easily cultured using the LB liquid medium, it was possible to culture at a wide range of 25 ~ 45 ℃.

In order to remove FNA, an impurity contained in CNDA, the microbial strains were inoculated in LB liquid medium, incubated with stirring at 30 ° C., and the cells were recovered by centrifugation.

The recovered cells were suspended in physiological saline and used as an enzyme solution for purification.

CNDA to be purified together with dimethylsulfoxide (DMSO), an organic solvent, phosphoric acid buffer solution (KH ₂ PO ₄ / KOH, pH 8.0) was added to the enzyme reaction tank containing the microbial suspension was added and the reaction proceeded with stirring at 25 to 45 ℃, especially at 30 ℃.

Carbon sources added to the reaction solution include glucose, fructose, ribose, trehalose, mannose, maltose, sucrose, dextrin, Cyclodextrin, citric acid, and succinic acid were used.

Phosphoric acid buffer solution (KH ₂ PO ₄ / KOH, pH 8.0) was used to mitigate the pH change of the reaction solution, but the pH of the reaction solution was found to be low due to the addition of high concentration of CNDA.

When the pH of the reaction solution is low, since the reaction proceeds in a suspended state without completely dissolving CNDA in the reaction solution, there is a problem that separation of the cells after the reaction is difficult.

In order to solve this problem, when the initial pH of the reaction solution was adjusted using KOH, when the pH of the reaction solution was less than 7.0, the reaction proceeded in a suspended state without completely dissolving CNDA. It was confirmed that it completely dissolved in the reaction solution.

As a result, the cells were easily separated after the reaction, and the cells were recovered to allow the continuous purification reaction.

In addition, in order to confirm the initial pH suitable for the reaction, the reaction was adjusted to pH 6.0 to 10.0.

As a result of the above experiment, 0.5% concentration of glucose was used as the carbon source added to the reaction solution, and the FNA reduction rate was the best when the initial pH was 8.0.

When the pH was lower than 6.0, the reaction did not proceed, and when the concentration was higher than 8.0, the decrease rate of FNA decreased.

Example 1

Bacillus F-3 was incubated in LB liquid medium to recover the cells, and then suspended in 5 ml of 0.85% saline was used for the reaction.

As shown in Table 1, CNDA containing 0.1% of FNA was used as a reactor to be purified, 0.1 M KH ₂ PO ₄ / KOH (pH 8.0) was used as a buffer, and the concentration of DMSO, an organic solvent, was 5%, The reaction temperature was 30 deg. C to purify CNDA.

As the carbon source, glucose was added at a concentration of 0.5%, and the initial pH of the reaction solution was adjusted to 8.0 to start the reaction.

<Table 1> Composition of reaction solution

microbe CNDA Buffer Initial pH of the reaction solution Carbon source DMSO Reaction temperature Bacillus F-3 FNA content0.1% 0.1 MKH ₂ PO ₄ / KOH 8.0 Glucose 0.5% concentration 5% concentration 30 ℃

The reaction solution was analyzed using high performance liquid chromatography (HPLC) under the conditions shown in Table 2.

As a result, as shown in Table 4, FNA decreases rapidly, and the result is not detected in 1 hour of reaction time.

<Table 2> HPLC Analysis Conditions

HPLC LC 10-AD VP (SHIMADZU) Column ^{XTerra TM RP18 (4.6 × 250 mm} , Waters) Detector  UV 240 nm Column temp.  40 ℃ Flow rate  1 ml / min. Injection volume  20 μl Mobile phase Time (minutes) 0.3% Phosphoric acid 100% Acetonitrile 0 98 2 5 92 8 28 52 48 30 20 80 35 5 95 36 98 2 49 98 2

Examples 2 to 22

In order to optimize the purification reaction, the reaction of naphthalenedicarboxylic acid (NDA) was performed while changing the type of carbon source, the concentration of the carbon source, and the initial pH of the reaction solution as shown in Table 3 using F. genus Bacillus. FNA reduction rate was compared.

The buffer solution of the reaction solution composition not shown in Table 3 was 0.1 M KH ₂ PO ₄ / KOH (pH 8.0), the organic solvent was DMSO 5%, the reaction temperature was the same as 30 ℃.

After 3 hours, the reaction solution was collected and analyzed under the same analysis conditions as in Table 2. The results are summarized in Table 4.

<Table 3> Changes in Composition of Purification Reactions

FNA content in CNDA Carbon element Initial pH of the reaction solution Kinds Concentration Example 2 0.1% - - 6.5 Example 3 0.1% - - 8.0 Example 4 10% - - 8.0 Example 5 10% Glucose 0.5% 8.0 Example 6 10% Fructose 0.5% 8.0 Example 7 10% Trehalose 0.5% 8.0 Example 8 10% Ribose 0.5% 8.0 Example 9 10% Mannose 0.5% 8.0 Example 10 10% maltose 0.5% 8.0 Example 11 10% Sucrose 0.5% 8.0 Example 12 10% dextrin 0.5% 8.0 Example 13 10% Cyclodextrin 0.5% 8.0 Example 14 10% Citric acid 0.5% 8.0 Example 15 10% Succinic acid 0.5% 8.0 Example 16 10% Glucose 0.1% 8.0 Example 17 10% Glucose 0.2% 8.0 Example 18 10% Glucose 1.0% 8.0 Example 19 10% Glucose 5.0% 8.0 Example 20 10% Glucose 0.5% 6.0 Example 21 10% Glucose 0.5% 7.0 Example 22 10% Glucose 0.5% 9.0

Comparative Example 1

In order to confirm the case where the initial pH of the reaction solution was 10.0, the experiment was performed by changing the buffer solution to 0.1 M Na ₂ CO ₃ / NaHCO ₃ .

In the case of 0.1 M KH ₂ PO ₄ / KOH, the experiment was performed by replacing the buffer solution because the pH 10.0 is out of the buffer range.

As a carbon source, 0.5% of glucose was added, and all other conditions were the same as in Example 1.

After 3 hours, the reaction solution was collected and analyzed by HPLC, and the results are summarized in Table 4.

Example 23

Purification reaction was performed again using the recovered cells after the completion of the purification reaction.

After carrying out the purification reaction under the same conditions as in Table 1, the whole reaction solution was centrifuged to separate only the cells, and then the cells were added again to the reaction solution having the same composition as in Table 1 to carry out the second purification reaction.

In the same manner, the fourth purification reaction was carried out to determine whether the continuous purification reaction was possible.

As shown in Table 5, the FNA reduction rate of 97% was maintained until the fifth purification reaction.

Therefore, it seems that it is possible to continue the purification by recovering the cells.

Example 24

In comparison with Example 23, in which the entire reaction solution was replaced, only 20% of the reaction solution was replaced, followed by continuous purification.

After the first purification reaction, only 20% of the reaction solution was centrifuged to recover the cells, and then added to the remaining reaction solution, adjusted to the same composition as the first reaction solution, followed by the purification reaction. Proceed to

As a result, as shown in Table 5, a high FNA reduction rate was obtained, but the decrease rate decreased as the reaction was repeated.

<Table 4> Reduction rate of FNA after 3 hours of purification

Example No. Response variables % Decrease in FNA Remarks One Glucose 0.5% / Initial pH 8.0 100.0 FNA content: 0.1% / 1 hour reaction 2 No carbon source / initial pH 6.5 95.1 FNA content: 0.1% / 6 hours reaction 3 No carbon source / initial pH 8.0 95.5 FNA content: 0.1% 4 No carbon source / initial pH 8.0 77.4 FNA content: 10% 5 Carbon source Kinds Glucose 0.5% 96.8 FNA content: 10% 6 Fructose 0.5% 87.1 FNA content: 10% 7 Trehalose 0.5% 94.7 FNA content: 10% Ribose 0.5% 81.2 FNA content: 10% 8 9 Mannose 0.5% 85.8 FNA content: 10% 10 Maltose 0.5% 91.7 FNA content: 10% 11 Sucrose 0.5% 87.3 FNA content: 10% 12 Dextrin 0.5% 89.8 FNA content: 10% 13 Cyclodextrin 0.5% 84.2 FNA content: 10% 14 Citric acid 0.5% 54.1 FNA content: 10% 15 Succinic Acid 0.5% 71.0 FNA content: 10% 16 Carbon source concentration Glucose 0.1% 84.1 FNA content: 10% 17 Glucose 0.2% 89.4 FNA content: 10% 18 Glucose 1.0% 96.9 FNA content: 10% 19 Glucose 5.0% 97.0 FNA content: 10% 20 Reaction solution Initial pH Initial pH 6.0 1.2 FNA content: 10% 21 Initial pH 7.0 90.4 FNA content: 10% 22 Initial pH 9.0 78.9 FNA content: 10% Comparative Example 1 Initial pH 10.0 41.2 FNA content: 10%

<Table 5> Reduction rate of FNA during purification after cell recovery

Purification Reaction FNA Reduction (%) Example 23 Primary 96.8 Secondary 96.9 3rd 97.2 4th 97.6 5th 97.7 Example 24 Primary 96.7 Secondary 95.2 3rd 94.0 4th 92.7 5th 91.8

The present invention is not limited to the embodiments described above, and various modifications and changes can be made by those skilled in the art, which are included in the spirit and scope of the present invention as defined in the appended claims.

The present invention can effectively remove FNA in CNDA using Bacillus sp F-3 cells, furthermore, by adding glucose as a carbon source to the reaction solution and adjusting the pH to 8.0, FNA can be removed more quickly.

In addition, the present invention can be continuously recycled F-3 cells in Bacillus can be purified NDA continuously and efficiently.

1 is a scheme illustrating a process of synthesizing NDA and NDC by oxidizing DMN.

2 is a scheme showing the product upon oxidation of DMN.

Claims (6)

Crude Naphthalene Dicarboxylic Acid (CNDA) is used as a substrate, phosphate buffer (KH ₂ PO ₄ / KOH, pH 8.0) and dimethyl sulfoxide (Dimethyl sulfoxide) as a solvent are added to the substrate. After making the reaction solution, Bacillus sp. F-3 cells (KCTC-10335BP) were added to the reaction solution, and then the pH of the reaction solution was 6.0 to 10.0, and the temperature was maintained at 25 to 45 ° C. A method for purifying 2,6-naphthalene dicarboxylic acid using a microorganism, characterized in that the reaction removes 2-formyl-6-naphthoic acid contained in CNDA. The method for purifying 2,6-naphthalene dicarboxylic acid using a microorganism according to claim 1, wherein a carbon source is added to the reaction solution. The method of claim 2, wherein the carbon source is glucose, fructose, trehalose, ribose, mannose, maltose, sucrose, dextrin, A method for purifying 2,6-naphthalene dicarboxylic acid using a microorganism, characterized by using a carbon source selected from the group consisting of cyclodextrin, citric acid, and succinic acid. According to claim 1, 2,6-naphthalene using a microorganism, characterized in that after the purification reaction to remove the cells from all or a part of the reaction solution, mixed with a new reaction solution or an existing reaction solution to continue the purification reaction Method for Purifying Dicarboxylic Acid. The method for purifying 2,6-naphthalene dicarboxylic acid using a microorganism according to claim 2, wherein the carbon source is glucose at a concentration of 5%. The method for purifying 2,6-naphthalene dicarboxylic acid using a microorganism according to claim 1, wherein the initial pH of the reaction solution is adjusted to 8.0.