KR20240006095A - A Method for synthesis of monomers using microreactor - Google Patents

Abstract

The present invention relates to a method for synthesizing 3,4-oxydianiline, one of core monomers of a copolymer aramid super fiber, with ultra-high yield and ultra-high purity using a microreactor. More specifically, the present invention relates to relates to the method for synthesizing 3-(4-nitrophenoxy)aniline, an intermediate, using a microreactor, and then reducing the intermediate by adding hydrazine to synthesize a final product, 3,4-ODA. The synthesis method using the microreactor according to the present invention can synthesize monomers with higher purity than an existing synthesis method using a microreactor by increasing precision and controlling the possibility of other side reactions through rapid removal of harmful gases.

Description

{A Method for synthesis of monomers using microreactor}

The present invention relates to a method of synthesizing monomers for extreme performance copolymerization aramid polymerization using a microreactor. More specifically, 3,4-ODA (3 , 4-oxydianiline) in ultra-high yield and purity.

Despite the recent recession in many textile industries, the demand for and related markets for aramid-based fibers, which are considered super fibers, are growing explosively. The global aramid market size is expected to grow at an average annual rate of 9.4% from approximately $3.5 billion in 2018 to $6.5 billion in 25, and demand for defense and safety protection industries, friction materials for transportation equipment, tires, rubber reinforcements, and insulation materials is steadily increasing. In addition, demand for 5G optical cables in the Korean, North American, and European markets and for lightweight materials for automobiles and aviation in China, South America, and Southeast Asia are rapidly increasing. Currently, the domestic aramid market is worth about KRW 140 billion in 2018, accounting for 4.1% of the global market, and has been growing at an average annual rate of about 7% for the past three years. Domestic aramid exports began to gradually increase from the first half of 2017, reaching 19%. As of July, it is increasing to 512,000 tons.

Currently, para-aramid fiber can be produced domestically, but in the case of copolymerized aramid fiber, which has excellent fatigue resistance, rubber adhesion, and elongation, it can be used for different purposes than para-aramid, and its application field can be expanded due to its easier usability. Despite its high potential and growth potential, Japanese and French companies currently occupy the market in a monopoly and do not possess the original technology in Korea, making it impossible to participate in the market. In addition, since advanced overseas companies have a monopoly on the original technology and market, they are entirely dependent on imports of raw fiber materials. As a result, domestic production lines are paralyzed when material imports are disrupted in situations such as the recent trade war with Japan. It has a serious problem. Therefore, in order to reduce dependence on overseas imports of raw materials and make the material parts and equipment industry self-sufficient, the development of copolymerized aramid raw materials and self-sufficiency in processing technology are necessary.

Based on this information, it is very important to secure source technologies such as molecular design, polymerization, and spinning for extreme performance copolymerized aramid fibers, for which market demand is rapidly increasing. In particular, monomer selection and development of synthesis technology for molecular design are becoming important. The synthesis of monomers currently in use is very difficult, and easy synthesis, such as large-scale synthesis, requires the use of special equipment. Therefore, it is necessary to solve this problem and establish an easy monomer synthesis process and produce copolymerized aramid materials through this. In addition, manufacturing and commercializing intermediate materials for composite materials using this technology is very important, and through this, it is possible to secure the original technology for demonstrating composite parts and products in various advanced fields.

Accordingly, the present inventors made efforts to develop a new method for synthesizing monomers of extreme performance copolymerized aramid fibers, and as a result, the intermediate 3-(4-nitrophenoxy)aniline was synthesized using a microreactor rather than using existing glass glass. is first synthesized and then reduced by adding Hydrazine to synthesize the final product, 3,4-ODA (3,4-oxydianiline). In addition, the purification method is also different from the complex methods of existing work-up, extraction, and reduced pressure distillation. The present invention was completed by confirming that 3,4-ODA, one of the key monomers of copolymerized aramid superfibers, can be synthesized with ultra-high yield and ultra-high purity by completing a simple method of directly precipitating the filtrate.

Nobuyuki Mase, et al., Measurement of Ultrafine Bubbles in Organic Solvents Synlett 2017, 49, 2184-2188 Debabrata Maiti, et al., J. AM. CHEM. SOC. 2009, 131, 17423-17429

The purpose of the present invention is to synthesize 3,4-ODA (3,4-oxydianiline) monomer for extreme performance copolymerization aramid polymerization. By adopting a method of synthesis through a microreactor, the precision of synthesis is increased compared to existing methods and an improved purification method is used. To provide a method for producing high purity 3,4-ODA (3,4-oxydianiline) monomer quickly and easily by increasing the yield and purity.

In order to achieve the above object, the present invention

1) Add 1-chloro-4-nitrobenzene, 3-aminophenol, K ₂ CO ₃ , Fe ₂ O ₃ and solvent to the microreactor and react 3- Synthesizing (4-nitrophenoxy)aniline (3-(4-nitrophenoxy)aniline);

2) After filtering the crude solution reacted in step 1) to remove Fe ₂ O ₃ , pour the remaining filtrate into distilled water to crystallize it, filter it to precipitate crystals, and then dissolve the crystals in ethanol. Pour into distilled water to crystallize, filter to precipitate the final product, and then dry in a vacuum oven to purify 3-(4-nitrophenoxy)aniline;

3) Add 3-(4-nitrophenoxy)aniline, Pd/C, EtOH, and Hydrazine purified in step 2) to the microreactor and react to produce 3,4-oxydianiline. ) synthesizing; and

4) After the crude solution reacted in step 3) was filtered to remove Pd/C, the remaining filtrate was poured into distilled water to crystallize, filtered to precipitate the final product, and then dried in a vacuum oven to obtain 3, A method for synthesizing 3,4-oxydianiline using a microreactor is provided, including the step of purifying 4-oxydianiline.

Additionally, the present invention provides 3,4-oxydianiline prepared by the method according to the present invention.

In addition, the present invention provides an aramid copolymer containing 3,4-oxydianiline according to the present invention.

The present invention is an extreme performance copolymerized aramid monomer synthesis using a microreactor, which improves precision when synthesizing using a microreactor compared to the existing method and controls the possibility of other side reactions through rapid removal of harmful gases, thereby producing a highly purified monomer that is further improved. can be synthesized.

In addition, rather than obtaining the product through the existing work-up, extraction, and vacuum distillation methods, an easier purification method was designed by precipitating the product at once, enabling the synthesis of monomers with ultra-high purity and high yield. can be secured simultaneously.

Through this, the synthesis method of the present invention can contribute to the optimization of the 3,4-ODA (3,4-oxydianiline) monomer synthesis process, which is one of the original technologies for producing copolymer aramid superfibers, and the synthesis method of the present invention also has a similar structure. Genie can also be applied to the synthesis of other organic materials and applied to a variety of uses.

Figure 1 is a diagram showing the synthesis of 3-(4-nitrophenoxy)aniline using a conventional synthesis method.
Figure 2 is a diagram showing the synthesis of 3,4-oxydianiline in the microreactor synthesis method according to the present invention.
Figure 3 is a diagram showing the synthesis process using Hydrazine using general vinegar, which is an existing synthesis method.
Figure 4 is a diagram showing the synthesis process using Hydrazine using a microreactor according to the present invention.
Figure 5 is a graph showing GC-MASS purity analysis of 3,4-oxydianiline using a conventional synthesis method.
Figure 6 is a graph showing GC-MASS purity analysis of 3,4-oxydianiline synthesized in a microreactor according to the present invention.

Hereinafter, the present invention will be described in detail.

In describing the present invention, detailed descriptions of related known structures or functions may be omitted. Terms or words used in this specification and patent claims should not be construed as limited to their usual or dictionary meanings, but should be construed with meanings and concepts consistent with the technical details of the present invention. The embodiments described in this specification and the configurations shown in the drawings are preferred embodiments of the present invention, and do not represent the entire technical idea of the present invention, so various equivalents and modifications that can replace them at the time of filing the present application are available. There may be.

This invention

1) Add 1-chloro-4-nitrobenzene, 3-aminophenol, K ₂ CO ₃ , Fe ₂ O ₃ and solvent to the microreactor and react 3- Synthesizing (4-nitrophenoxy)aniline (3-(4-nitrophenoxy)aniline);

2) After filtering the crude solution reacted in step 1) to remove Fe ₂ O ₃ , pour the remaining filtrate into distilled water to crystallize it, filter it to precipitate crystals, and then dissolve the crystals in ethanol. Pour into distilled water to crystallize, filter to precipitate the final product, and then dry in a vacuum oven to purify 3-(4-nitrophenoxy)aniline;

3) Add 3-(4-nitrophenoxy)aniline, Pd/C, EtOH, and Hydrazine purified in step 2) to the microreactor and react to produce 3,4-oxydianiline. ) synthesizing; and

4) After the crude solution reacted in step 3) was filtered to remove Pd/C, the remaining filtrate was poured into distilled water to crystallize, filtered to precipitate the final product, and then dried in a vacuum oven to obtain 3, A method for synthesizing 3,4-oxydianiline using a microreactor is provided, including the step of purifying 4-oxydianiline.

In the above synthesis method, the reaction in step 1) is preferably carried out at 150 to 160°C for 30 minutes to 1 hour and 30 minutes, and more preferably at 150 to 153°C for 1 hour.

In the above synthesis method, crystallization and drying in step 2) are preferably performed for 12 hours or more, and crystallization and drying are more preferably performed for 12 to 14 hours.

In the above synthesis method, the reaction in step 3) is preferably performed for 30 minutes to 1 hour, and more preferably for 30 minutes to 40 minutes.

In the above synthesis method, crystallization and drying in step 4) are preferably performed for 12 hours or more, and crystallization and drying are more preferably performed for 12 to 14 hours.

Specifically, the present invention is an invention that improves the currently commonly used 3,4-ODA synthesis method using glassware by using a microreactor to improve precision and simplify the purification method.

Specifically, the differences between the present invention and the existing synthesis method using glassware are as follows. The synthesis process of the existing method (general microsynthesis) and the new method (microreactor synthesis) is shown in Figures 3 and 4. When using a microreactor, the purification process is simple and the final product appears more transparent.

Intermediate synthesis

The method using the microreactor according to the present invention has no differences in precursors from the conventional synthesis method, but there is a difference in reaction temperature and time. The existing method of proceeding the reaction through an oil bath using a glassware proceeds at around 130°C to prepare for reflux and risk, whereas the reaction using a microreactor requires boiling of DMF, a solvent, to increase precision. The reaction proceeds by raising the temperature to the point.

In addition, due to the nature of the microreactor reactor, which uses microwaves and a pressure of about 1.5 bar, it is possible to complete the reaction in a very short time, about 1 hour, compared to the existing reaction time of about 4 hours and 30 minutes. The yield of the reaction is 89% for the existing method, and the new method using a microreactor can significantly increase it to 96%.

Therefore, intermediate synthesis using a microreactor enables more precise synthesis, higher yield, and reduces reaction time, showing superior characteristics than existing reactions.

intermediate purification

In the existing method, Fe ₂ O ₃ is sufficiently removed through filtering in the crude solution state, then poured into cold distilled water to crystallize. After filtering out the crystals, the extraction process is performed three or more times using EA and distilled water. . Afterwards, the product extracted with EA is subjected to reduced pressure distillation to remove the solvent, and then the remaining product is taken. However, because there are impurities and solvents that are not completely removed during this process, the final product remains in a highly concentrated liquid form. Therefore, there is the inconvenience of having to wash and solidify the product.

On the other hand, the method using the microreactor according to the present invention sufficiently removes Fe ₂ O ₃ through filtering in the crude solution state, then pours it into cold distilled water to proceed with crystallization, filters out the crystals through a filter, and then filters the product into EtOH. It melts. Pour the well-dissolved solution into 3 times distilled water to crystallize the clean product. After 12 hours, the product that has sufficiently crystallized is filtered and dried in a vacuum oven.

The existing method using glass does not require temperature or reflux as the reaction proceeds at room temperature, but hydrogen gas and ammonia gas are generated during the reaction using hydrazine. Hydrogen gas and ammonia gas are dangerous gases, potentially explosive and toxic, so extreme caution must be exercised at the production site. On the other hand, in the reaction using a microreactor, there is no risk of gas leakage because hydrogen gas and ammonia gas are naturally discharged.

Additionally, since gas removal is easy, the precision and yield of the reaction also increase.

Lastly, in the existing reduction method, the reduction reaction time becomes longer as the amount increases, but the reduction method using a microreactor can induce a reduction time as short as about half due to the influence of microwaves and pressure. The yield of the reaction is 71% in the existing method, and can be increased to 84% in the new method using a microreactor.

Therefore, final monomer synthesis using a microreactor enables more precise synthesis, has higher yield, and reduces reaction time, showing superior characteristics than existing reactions.

Final product purification

In the existing method, Pd/C is filtered out by filtering the solution after the reaction is completed. Afterwards, the extraction process is repeated three or more times using EA and water, and the product is obtained through reduced pressure distillation. At this time, the highly concentrated product due to impurities and remaining solvent is obtained through column purification, and then obtained again through reduced pressure distillation.

On the other hand, in the method using the microreactor according to the present invention, Pd/C is filtered out by filtering the solution after the reaction is completed. Afterwards, pour in 5 times more distilled water and let it crystallize immediately. After 12 hours, the crystallized solution was filtered and dried in a vacuum oven.

As a final result, 3,4-ODA obtained by the conventional method showed a purity of about 96.87%, while the purity analysis result of 3,4-ODA synthesized using a microreactor showed an ultrapure product of 100%. can do. The reason is that precise synthesis was possible using a synthesis method controlled by a microreactor, and by-product gases could be removed in real time.

In addition, thanks to the new microreactor utilization method, the purification method for monomer synthesis was also made much simpler. When the purity of the monomer approaches 100%, the subsequent polymerization process can proceed very easily.

Therefore, the method of synthesizing and purifying monomers using the microreactor of the present invention has the advantage of being able to quickly and easily obtain ultra-high purity products in high yield, which is advantageous for mass production and commercialization of copolymerized aramid superfibers.

Additionally, the present invention provides 3,4-oxydianiline with a purity of 99 to 100% prepared by the method according to the present invention.

As a result of comparative analysis of purity in the examples of the present invention, 3,4-ODA obtained by the conventional method showed a purity of about 96.87%, while 3,4-ODA synthesized by the method using the microreactor according to the present invention The purity analysis results confirmed that a 100% ultrapure product could be obtained.

Additionally, the present invention provides an aramid copolymer containing 3,4-oxydianiline according to the present invention.

The aramid copolymer can be synthesized by dissolving a diamine compound containing 3,4-oxydianiline and at least one of an aromatic dianhydride, an aromatic halide, or an aromatic dicarbonyl compound in a polymerization solvent and then reacting.

In addition, the present invention provides an aramid fiber containing the aramid copolymer according to the present invention.

The aramid fiber can be prepared by dissolving the aramid copolymer in a solvent to prepare spinning dope, and then spinning, coagulating, washing, drying, and heat treating the spinning dope as in a typical aramid fiber production method, or aramid aerial Aramid fibers can be manufactured by spinning, coagulating, washing, drying, and heat treating the polymerization solvent containing the polymer as a spinning dope.

Hereinafter, the present invention will be described in more detail through examples and experimental examples.

These examples and experimental examples are only for illustrating the present invention in more detail, and it is understood by those skilled in the art that the scope of the present invention is not limited by these examples and experimental examples according to the gist of the present invention. It is self-evident to anyone.

<Example 1> Synthesis of 3-(4-nitrophenoxy)aniline

<1-1> Synthesis of 3-(4-nitrophenoxy)aniline

1.56 g of 1-chloro-4-nitrobenzene, 1.1 g of 3-aminophenol, 1.66 g of K ₂ CO ₃ , and 1.66 g of Fe ₂ in a 30 mL microreactor-specific glass vial reactor. 0.024 g of O ₃ and 10 mL of DMF were added and mounted inside the microreactor. The reaction temperature was set to 150°C and the reaction time was set to 1 hour, and the reaction was started (Figure 2).

<1-2> Purification of 3-(4-nitrophenoxy)aniline

After completing the experiment, the crude solution was sufficiently cooled to room temperature and filtered twice to remove Fe ₂ O ₃ used in the experiment. The remaining filtrate was poured into distilled water to induce precipitation of the reaction product. To wash the precipitated product after 12 hours, it was dissolved in 10 mL of ethanol and poured into 30 mL of distilled water to induce precipitation of the final product. After 12 hours, the precipitated product was filtered and dried in a vacuum oven for 12 hours.

<Example 2> Synthesis of 3,4-oxydianiline

<2-1> Synthesis of 3,4-oxydianiline

Add 1 g of Experiment 1 intermediate 3-(4-nitrophenoxy)aniline, 0.04 g of Pd/C, and 15 mL of EtOH to a 30 mL microreactor glass vial reactor and perform reduction. After adding 0.5 mL of Hydrazine, it was mounted inside the microreactor. The reaction time was set to 30 minutes and the reaction was started (Figure 4).

<2-2> Purification of 3,4-oxydianiline

After completing the experiment, the crude solution was filtered once to remove the Pd/C used in the experiment. The remaining filtrate was poured into 75 mL of distilled water to induce precipitation of the reaction product. After 12 hours, the precipitated product was filtered and dried in a vacuum oven for 12 hours.

<Comparative Example 1> Synthesis of 3-(4-nitrophenoxy)aniline according to existing synthesis method

As for the existing synthesis method, V. Yu. 3-(4-nitrophenoxy)aniline was synthesized using Orlov, et al., Russian Journal of General Chemistry, 2017, 87, 3, 386-388, and impurities were found during synthesis, and Debabrata Maiti, et al. ., J. AM. CHEM. SOC. The work-up process was performed using 2009, 131, 17423-17429 (Figure 1).

Specifically, 1-chloro-4-nitrobenzene, 3-aminophenol, K ₂ CO ₃ and Fe ₂ O ₃ were added to the glass at a ratio of 1: 1: 1.2: 0.15. After adding 10 mL DMF as a solvent, the reaction was performed at a reaction temperature of 130°C and a reaction time of 4.5 hours.

After sufficiently removing Fe ₂ O ₃ through filtering in the crude solution, crystallization was performed by pouring it into cold distilled water. After filtering out the crystals, the extraction process was performed more than three times using EA and distilled water. Afterwards, the product extracted with EA was subjected to reduced pressure distillation to remove the solvent, and the remaining product was taken. However, because there were impurities and solvents that were not completely removed during this process, the final product remained a highly concentrated liquid. Therefore, washing and solidification of the product were carried out.

<Comparative Example 2> Synthesis of 3,4-oxydianiline according to existing synthesis method

Using Xia Chen, et al., SYNTHETIC COMMUNICATIONS , 2018, 48, 19, 2475-2484, 3-(4-nitrophenoxy)aniline compound was reduced to 3,4-oxydianiline through a reducing agent (Figure 3 ).

Specifically, 1 g of Experiment 1 intermediate 3-(4-nitrophenoxy)aniline, 0.04 g of Pd/C, and 15 mL of EtOH were added to the glassware, and hydrazine for reduction was added to the glassware. ) was added and reacted.

After the reaction was completed, the solution was filtered to remove Pd/C. Afterwards, the extraction process was repeated three or more times using EA and water, and the product was obtained through reduced pressure distillation. At this time, the highly concentrated product due to impurities and remaining solvent was obtained through column purification, and then again through reduced pressure distillation. Alternatively, the product was dissolved in a very small amount of EtOH and solidification was induced by pouring sufficient haxane, an anti-solvent.

<Experimental Example 1> Purity analysis of final synthesized 3,4-ODA

The purity of 3,4-ODA finally synthesized by the existing method (Comparative Examples 1 and 2) and the method using a microreactor (Examples 1 and 2) was analyzed using GC-MASS (Gas Chromatography-Mass Spectrometry). (Figures 5 and 6).

As a final result, 3,4-ODA obtained using the conventional method showed a purity of approximately 96.87%. However, the existing method not only took a long time, but the purification method was very complicated, so there were limitations as a mass production method for commercialization.

In contrast, the purity analysis result of 3,4-ODA synthesized using a microreactor was 100%, indicating that an ultrapure product was obtained. The reason is that precise synthesis was possible using a synthesis method controlled by a microreactor, and by-product gases could be removed in real time.

Thanks to the new microreactor utilization method according to the present invention, the purification method for monomer synthesis could be made much simpler. When the purity of the monomer approaches 100%, the subsequent polymerization process can proceed very easily. Therefore, the method of synthesizing and purifying monomers using the microreactor of the present invention has the advantage of being able to quickly and easily obtain ultra-high purity products in high yield, which is advantageous for mass production and commercialization of copolymerized aramid superfibers.

Claims (7)

1) Add 1-chloro-4-nitrobenzene, 3-aminophenol, K ₂ CO ₃ , Fe ₂ O ₃ and solvent to the microreactor and react 3- Synthesizing (4-nitrophenoxy)aniline (3-(4-nitrophenoxy)aniline);
2) After filtering the crude solution reacted in step 1) to remove Fe ₂ O ₃ , pour the remaining filtrate into distilled water to crystallize it, filter it to precipitate crystals, and then dissolve the crystals in ethanol. Pour into distilled water to crystallize, filter to precipitate the final product, and then dry in a vacuum oven to purify 3-(4-nitrophenoxy)aniline;
3) Add 3-(4-nitrophenoxy)aniline, Pd/C, EtOH, and Hydrazine purified in step 2) to the microreactor and react to produce 3,4-oxydianiline. ) synthesizing; and
4) After the crude solution reacted in step 3) was filtered to remove Pd/C, the remaining filtrate was poured into distilled water to crystallize, filtered to precipitate the final product, and then dried in a vacuum oven to obtain 3, Including the step of purifying 4-oxydianiline,
Method for synthesizing 3,4-oxydianiline using a microreactor.
According to paragraph 1,
A method of synthesizing 3,4-oxydianiline using a microreactor, wherein the reaction in step 1) is carried out at 150 to 160°C for 30 minutes to 1 hour and 30 minutes.
According to paragraph 1,
In step 2), crystallization is performed for 12 to 14 hours, and drying is performed for 12 to 14 hours.
According to paragraph 1,
A method for synthesizing 3,4-oxydianiline using a microreactor, characterized in that the reaction in step 3) is carried out for 30 minutes to 1 hour.
According to paragraph 1,
In step 4), crystallization is performed for 12 to 14 hours, and drying is performed for 12 to 14 hours.
Manufactured by the method of any one of claims 1 to 5,
3,4-oxydianiline, 99 to 100% pure.
An aramid copolymer containing the 3,4-oxydianiline of claim 6.