CN111808028A - A kind of synthetic method and application of aminobenzimidazole naphthalenesulfonic acid compound - Google Patents

Abstract

The invention relates to the technical field of preparation of aminonaphthalenesulfonic acid compounds, in particular to a synthesis method and application of an aminobenzimidazolenaphthalenesulfonic acid compound. The steps include: 1) dissolving 0.1 mol of carboxynaphthalene sulfonic acid and 0.15-0.25 mol of aminonitrobenzene in polyphosphoric acid to prepare a reaction solution; 2) placing the reaction solution in a reaction kettle, and raising the temperature to 180-200 ℃, react for 1.5-10 hours, then add water to separate out, filter to obtain intermediate product A; wash intermediate product A with acid to obtain intermediate product B; 3) dissolve intermediate product B in a solvent, and pass hydrogen gas under the action of a catalyst Get it back. In the present invention, the aminobenzimidazole naphthalenesulfonic acid compound with high yield and purity is obtained through the molecular design of the reaction monomer raw materials and the protection of groups such as amino groups in the reaction process, and the benzimidazole structure is successfully introduced into the binary Among the amine monomers, it is helpful to fuse the structures of polybenzimidazole and polyimide, and obtain a new material that combines the advantages of both.

Description

A kind of synthetic method and application of aminobenzimidazole naphthalenesulfonic acid compound

technical field

The invention relates to the technical field of preparation of aminonaphthalenesulfonic acid compounds, in particular to a synthesis method and application of an aminobenzimidazolenaphthalenesulfonic acid compound.

Background technique

Polyimide, polyamide, etc. are also well-known high-performance materials. They have the advantages of high thermal stability, high mechanical strength and modulus, radiation resistance, good film formation and excellent electrical properties. It has good solubility in aprotic organic solvents, so the processing performance is good, but the acid resistance, alkali resistance and spinning performance of these materials are poor. and modulus, excellent chemical stability (especially acid and alkali resistance), good flame retardancy, high-performance polymer materials with excellent spinning and film-forming properties, used in aerospace, military, fire protection, fuel cells It has been widely researched and applied in other fields. However, polybenzimidazole is insoluble, infusible, and has poor processability, which limits its industrial application. Therefore, combining the structures of polybenzimidazole and polyimide is expected to obtain new materials that combine the advantages of both.

Imidazole-based polyimides or imidazole-based polyamides are usually formed by the polycondensation of aromatic dibasic acid anhydrides and imidazolyl-containing diamine monomers. Therefore, imidazolyl-containing diamines are the key monomer raw materials for the preparation of these two types of materials. So far, there are very few types of imidazole group-containing diamine monomers, which limits the development of imidazole group-containing polymers. Therefore, it is necessary to study an imidazole-based diamine monomer suitable for combining polybenzimidazole and polyimide.

SUMMARY OF THE INVENTION

In view of the above-mentioned technical problems, the first aspect of the present invention provides a kind of synthetic method of aminobenzimidazole naphthalenesulfonic acid compound, and it comprises the steps:

(1) Dissolving 0.1 mol of carboxylnaphthalene sulfonic acid and 0.15-0.25 mol of aminonitrobenzene in polyphosphoric acid to prepare a 5-55 wt% solution;

(2) above-mentioned reaction solution is placed in reactor, raise reactor temperature to 180～200 ℃, react 1.5～10 hours, then add water in reactor and separate out, filter to obtain intermediate product A; Washing to obtain intermediate product B;

(3) Dissolving the intermediate product B in an organic solvent, introducing hydrogen to reduce it under the action of a catalyst, and post-processing to obtain the aminobenzimidazolenaphthalenesulfonic acid compound.

As a preferred technical solution of the present invention, the catalyst in step (3) is a palladium-carbon catalyst.

As a preferred technical solution of the present invention, the post-treatment described in step (3) includes the following steps: filtering the reduced material, removing the catalyst, then concentrating until there is solid precipitation, adding water to precipitate the precipitate, and filtering the obtained filter The cake was rinsed with ethanol, filtered and dried under vacuum at 35-55°C.

As a preferred technical solution of the present invention, the acid in step (2) is hydrochloric acid, and its concentration is 0.8-1.2 mol/L.

As a kind of preferred technical scheme of the present invention, described aminonitrobenzene has following structural formula:

Wherein: R ₁ is selected from a hydrogen atom, a hydrocarbon group, a carboxyl group, an amino group, a hydroxyl group, a siloxane group and a cyano group.

As a preferred technical solution of the present invention, the carboxylnaphthalenesulfonic acid is a naphthalenesulfonic acid salt containing a carboxyl group in the structure.

As a preferred technical solution of the present invention, the carboxynaphthalene sulfonic acid has the following structure:

Wherein: R ₂ , R ₃ and R ₄ are substituents; the substituents are independently selected from one of hydrogen atom, hydrocarbon group, carboxyl group, amino group, hydroxyl group, siloxane group and cyano group.

As a preferred technical solution of the present invention, at least one of the R ₃ and R ₄ is a carboxyl group.

As a preferred technical solution of the present invention, the aminobenzimidazole naphthalenesulfonic acid compound has the following structural formula:

The second aspect of the present invention provides the application of the aminobenzimidazolenaphthalenesulfonic acid compound synthesized by the above-mentioned synthesis method of the aminobenzimidazolenaphthalenesulfonic acid compound in the field of polyamide and polyimide materials.

Beneficial effects: Since the acidity of the sulfonic acid group affects the reactivity between the carboxyl group and the amino group to a certain extent, the carboxylnaphthalene sulfonic acid compound monomer in the present invention needs to be treated with lye first, and the sodium sulfonate is synthesized from the sulfonic acid group. Then react with amino compounds. Secondly, in the present invention, the ortho-amino group and the carboxyl group are reacted in the polyphosphoric acid solution at 180-200 degrees Celsius, and the imidazole structure is obtained through dehydration condensation, which helps to ensure the bonding activity between the naphthalenesulfonic acid and the benzimidazole. Helps improve overall yield. In addition, in the present application, a nitro-containing diamine monomer is used to react with carboxylnaphthalenesulfonic acid, and then the nitro group is reduced under the action of a catalyst to obtain an amino group, thereby helping to avoid the carboxyl group in the carboxylnaphthalenesulfonic acid structure and all the monomers in the monomer. The random reaction between amino groups generates body-shaped cross-linked structural products, or hinders the formation of imidazole structures, resulting in numerous by-products, which seriously affect the yield and purity of the target product. To sum up, in the present invention, the aminobenzimidazole naphthalenesulfonic acid compound with high yield and purity is obtained through the molecular design of the reaction monomer raw materials and the protection of groups such as amino groups in the reaction process, and the benzimidazole structure is successfully formed. The introduction of the diamine monomer into the preparation of polyimide and polyamide helps to fuse the structures of polybenzimidazole and polyimide, and obtains a new material combining the advantages of the two.

Detailed ways

The technical features in the technical solutions provided by the present invention will be further clearly and completely described below with reference to the specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The words "preferred", "preferably", "more preferred" and the like in the present invention refer to embodiments of the invention which, under certain circumstances, may provide certain benefits. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not available, nor is it intended to exclude other embodiments from the scope of the present invention.

When an amount, concentration, or other value or parameter is expressed as a range, preferred range, or a range bounded by a series of upper preferred values and lower preferred values, this should be understood as specifically disclosing any upper range limit or preferred value and any lower range limit or all ranges formed by any pairing of preferred values, whether or not the ranges are individually disclosed. For example, when a range of "1 to 5" is disclosed, the described range should be construed to include the ranges "1 to 4," "1 to 3," "1 to 2," "1 to 2, and 4 to 5." , "1 to 3 and 5", etc. When numerical ranges are described herein, unless stated otherwise, the ranges are intended to include the endpoints and all integers and fractions within the range.

The singular form includes the plural object of discussion unless the context clearly dictates otherwise. "Optional" or "either" means that the subsequently described item or event may or may not occur, and that the description includes instances where the event occurs and instances where it does not.

As used herein, the term "prepared from" is synonymous with "comprising". As used herein, the terms "comprising," "including," "having," "containing," or any other variation thereof, are intended to cover non-exclusive inclusion. For example, a composition, step, method, article or device comprising the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such composition, step, method, article or device elements.

A first aspect of the present invention provides a synthetic method of an aminobenzimidazole naphthalenesulfonic acid compound, which comprises the following steps:

(1) Dissolving 0.1 mol of carboxylnaphthalene sulfonic acid and 0.15-0.25 mol of aminonitrobenzene in polyphosphoric acid to prepare a 5-55 wt% solution;

(2) above-mentioned reaction solution is placed in reactor, raise reactor temperature to 180～200 ℃, react 1.5～10 hours, then add water in reactor and separate out, filter to obtain intermediate product A; Washing to obtain intermediate product B;

(3) Dissolving the intermediate product B in an organic solvent, introducing hydrogen to reduce it under the action of a catalyst, and post-processing to obtain the aminobenzimidazolenaphthalenesulfonic acid compound.

Carboxynaphthalenesulfonic acid and aminonitrobenzene in the present invention are dissolved in polyphosphoric acid, and the solution is prepared and reacted under high temperature conditions. The polyphosphoric acid is a colorless, transparent, viscous liquid, which is a protonic acid known to those skilled in the art that can dissolve a variety of low-molecular and macromolecular organic compounds, and conventional polyphosphoric acid can be used in the present invention. In addition, the dissolved concentration of carboxynaphthalenesulfonic acid and aminonitrobenzene in polyphosphoric acid is not particularly limited in the present invention, and in some embodiments, the concentration is independently 5-55 wt%. In addition, nitrogen protection can be used in the reaction process of step (1).

In the present invention, carboxylnaphthalenesulfonic acid and aminonitrobenzene are reacted at 180 to 200° C. for 1.5 to 10 hours, wherein a dehydration condensation reaction is performed between the carboxyl group in the carboxylnaphthalenesulfonic acid structure and the amino group in the aminonitrobenzene. Under the long-term reaction, two molecules of water are removed between each mole of aminonitrobenzene and carboxynaphthalenesulfonic acid to form a benzimidazole structure, wherein the preferred reaction time is 2 to 6 hours. After the reaction, a large amount of water is used to separate out the intermediate product A, that is, the product after the nitro-containing benzimidazole and the naphthalene sulfonate are bonded. Since the intermediate product A is insoluble in water, a large amount of water is added to the system after the reaction, or the intermediate product A is precipitated when the reacted material is poured into a large amount of water while hot, and the solid intermediate product A is obtained through filtration, and the next step is to wait for it. use.

In the present invention, the intermediate product A is washed with acid to obtain the intermediate product B. Specifically, the intermediate product A on the filter cake after filtration can be washed with acid for many times, and then dried to obtain the intermediate product B. After the acid washing, the intermediate product B can be obtained. The sulfonic acid in the intermediate product A is hydrochloricated to obtain a sulfonic acid group, and the acid is not particularly limited, and various acids well known to those skilled in the art can be selected.

In some embodiments, the acid in step (2) is hydrochloric acid, and its concentration is 0.8-1.2 mol/L; preferably, its concentration is 1.0 mol/L.

Under the action of a catalyst, the intermediate product B of the present invention is introduced into hydrogen to reduce the nitro group in its structure to an amino group to obtain the target product. The organic solvent is not particularly limited, and various solvents known to those skilled in the art can be selected, including but not limited to DMF, DMAc, DMSO and other solvents, preferably DMAc.

In some embodiments, the catalyst in step (3) is a palladium-carbon catalyst.

In some embodiments, the post-processing described in step (3) includes the following steps: filtering the reduced material, removing the catalyst, then concentrating until there is solid precipitation, adding water to precipitate the precipitation, and leaching the obtained filter cake with ethanol after filtration Wash, filter and dry under vacuum at 35-55°C. Further, the reduced material is filtered, the catalyst is filtered off, concentrated by rotary evaporation until a solid is precipitated, then water is added to precipitate a large amount of precipitate, and the filter cake obtained after filtration is rinsed 2-3 times with ethanol. After filtration, it was vacuum-dried at 40°C.

In the step (3) of the present invention, the intermediate product B is dissolved in an organic solvent, and hydrogen is introduced under the action of a catalyst for reduction. The specific operation of the reduction reaction is not particularly limited. The reaction can be carried out at normal temperature and pressure, and can The reaction kettle is evacuated to remove oxygen and other oxidizing gases, and then hydrogen is introduced. In order to ensure that the oxidative gas content in the reaction kettle is reduced to a specific value, multiple replacement methods can be used to remove the oxidative gas in the reaction kettle. , and then the nitro group in the intermediate product B is reduced to an amino group by hydrogen under the action of a catalyst to obtain the target product.

Since the acidity of the sulfonic acid group affects the reactivity between the carboxyl group and the amino group to a certain extent, the carboxylnaphthalenesulfonic acid compound monomer in the present invention needs to be treated with alkali solution first, and then the sodium sulfonate is synthesized from the sulfonic acid group and then mixed with Amino compound reaction. Secondly, in the present invention, the ortho-amino group and the carboxyl group are used to react at 180-200 degrees Celsius in the polyphosphoric acid solution, and the imidazole structure is obtained through dehydration condensation, which helps to ensure the bonding activity between the naphthalenesulfonic acid and the benzimidazole. Helps improve overall yield. In addition, in this application, a nitro-containing diamine monomer is used to react with carboxylnaphthalenesulfonic acid, and then the nitro group is reduced under the action of a catalyst to obtain an amino group, thereby helping to avoid the carboxyl group in the carboxylnaphthalenesulfonic acid structure and all the monomers in the monomer. The random reaction between amino groups generates body-shaped cross-linked structural products, or hinders the formation of imidazole structures, resulting in numerous by-products, which seriously affect the yield and purity of the target product.

In some embodiments, the aminonitrobenzene is a compound containing both amino and nitro groups in the structure, and it has the following structural formula:

Wherein: R ₁ is selected from a hydrogen atom, a hydrocarbon group, a carboxyl group, an amino group, a hydroxyl group, a siloxane group and a cyano group.

The aminonitrobenzene in the present invention is a compound containing both amino groups and nitro groups in the structure, wherein the number of amino groups in each aminonitrobenzene structure is at least two, and the two are on adjacent carbon atoms of the benzene ring. . In addition, the position of the nitro group in the structure is not particularly limited, and it can be at any position of the remaining 4 carbons of the benzene ring. The aminonitrobenzene in the present invention also includes compounds containing substituents in the structure, namely R ₁ in the above-mentioned structural formula. The structure and position of the above-mentioned substituents are not particularly limited in the present invention, and they can be hydrogen atoms. , a hydrocarbon group, a carboxyl group, an amino group, a hydroxyl group, a siloxane group, and a cyano group. Preferably, the R ₁ is a hydrogen atom.

In some preferred embodiments, the aminonitrobenzene has the following structural formula:

In some embodiments, the carboxynaphthalenesulfonic acid is a naphthalenesulfonic acid salt containing a carboxyl group in its structure.

Further, described carboxynaphthalene sulfonic acid has the following structure:

Wherein: R ₂ , R ₃ and R ₄ are substituents; the substituents are independently selected from one of hydrogen atom, hydrocarbon group, carboxyl group, amino group, hydroxyl group, siloxane group and cyano group. Further, at least one of the R ₃ and R ₄ is a carboxyl group.

Each carboxynaphthalenesulfonic acid structure in the present invention contains at least one carboxyl group, preferably two carboxyl groups. In addition, the position of the sulfonic acid group in the carboxylnaphthalenesulfonic acid structure in the present application is not particularly limited, and it is preferred that the carboxyl group and the sulfonic acid group are on two different benzene rings, respectively. In addition, the carboxylnaphthalenesulfonic acid in the present invention includes the case where groups other than the carboxyl group and the sodium sulfonate group are substituted, that is, R ₂ , R ₃ and R ₄ are substituents; the substituents are independently One selected from the group consisting of hydrogen atom, hydrocarbon group, carboxyl group, amino group, hydroxyl group, siloxane group and cyano group. Preferably, R ₂ is a hydrogen atom, and one of R ₃ and R ₄ is a carboxyl group, and the other is a hydrogen atom.

Preferably, the carboxynaphthalene sulfonic acid has the following structural formula:

In one embodiment, the aminobenzimidazolenaphthalenesulfonic acid compound has the following structural formula:

Further, the synthetic equation of described aminobenzimidazole naphthalenesulfonic acid compound is as follows:

The second aspect of the present invention provides the application of the aminobenzimidazolenaphthalenesulfonic acid compound synthesized by the above-mentioned synthesis method of the aminobenzimidazolenaphthalenesulfonic acid compound in the field of polyamide and polyimide materials.

The present invention will be specifically described below by means of examples. It is necessary to point out that the following examples are only used to further illustrate the present invention, and should not be construed as limiting the protection scope of the present invention.

Example

Embodiment 1 : This embodiment provides a kind of synthetic method of aminobenzimidazole naphthalenesulfonic acid compound, and it comprises the following steps:

(1) 0.1mol carboxynaphthalenesulfonic acid and 0.2mol aminonitrobenzene are dissolved in the polyphosphoric acid that 100g mass concentration is 86%, prepare reaction solution;

(2) place the reaction solution in the above-mentioned steps (1) in the reactor, raise the temperature of the reactor to 200 ° C, react under nitrogen protection for 6 hours, then pour the material in the reactor into a large amount of water to separate out solid, the precipitated solid is filtered to obtain intermediate product A; then intermediate product A is washed 3 times with 1 mol/L hydrochloric acid to obtain intermediate product B;

(3) adding 80ml DMAc stirring and dissolving to above-mentioned intermediate product B in a 250ml three-necked flask, and adding a 0.8g palladium-carbon catalyst, after stirring and mixing, feed into nitrogen to replace the oxidizing gas in the three-necked flask, then vacuumize, feed into The hydrogen reduction reaction was carried out for 4 hours, and then the reduced material was filtered, the catalyst was filtered off, concentrated by rotary evaporation until a solid was precipitated, and then a large amount of precipitate was precipitated by adding water. After vacuum drying at 40°C, a product with a total molar yield of 90% and a purity of 98.8% was obtained.

Wherein the aminonitrobenzene has the following structural formula (1), and the carboxynaphthalene sulfonic acid has the following structural formula (2)

The synthetic equation of described aminobenzimidazolenaphthalenesulfonic acid compound is as follows:

Embodiment 2 : This embodiment provides a kind of synthetic method of aminobenzimidazole naphthalenesulfonic acid compound, and it comprises the following steps:

(1) 0.1mol carboxynaphthalenesulfonic acid and 0.2mol aminonitrobenzene are dissolved in the polyphosphoric acid that 100g mass concentration is 86%, prepare reaction solution;

(2) place the reaction solution in the above-mentioned steps (1) in the reactor, raise the temperature of the reactor to 200 ° C, react under nitrogen protection for 3 hours, then pour the material in the reactor into a large amount of water to separate out solid, the precipitated solid is filtered to obtain intermediate product A; then intermediate product A is washed 3 times with 1 mol/L hydrochloric acid to obtain intermediate product B;

(3) adding 80ml DMAc stirring and dissolving to above-mentioned intermediate product B in a 250ml three-necked flask, and adding a 0.8g palladium-carbon catalyst, after stirring and mixing, feed into nitrogen to replace the oxidizing gas in the three-necked flask, then vacuumize, feed into The hydrogen reduction reaction was carried out for 2.5 hours, then the reduced material was filtered, the catalyst was filtered off, concentrated by rotary evaporation until a solid was precipitated, and then a large amount of precipitate was precipitated by adding water. After vacuum drying at 40°C, a product with a total molar yield of 83% and a purity of 99.2% was obtained.

Wherein the aminonitrobenzene has the following structural formula (1), and the carboxynaphthalene sulfonic acid has the following structural formula (2)

Embodiment 3 : This embodiment provides a kind of synthetic method of aminobenzimidazole naphthalenesulfonic acid compound, and it comprises the following steps:

(1) 0.1mol carboxynaphthalenesulfonic acid and 0.2mol aminonitrobenzene are dissolved in the polyphosphoric acid that 100g mass concentration is 86%, prepare reaction solution;

(2) the reaction solution in the above-mentioned steps (1) is placed in the reactor, the temperature of the reactor is raised to 180 ° C, and reacted for 4 hours under nitrogen protection, then the material in the reactor is poured into a large amount of water to separate out solid, the precipitated solid is filtered to obtain intermediate product A; then intermediate product A is washed 3 times with 1 mol/L hydrochloric acid to obtain intermediate product B;

(3) adding 80ml DMAc stirring and dissolving to above-mentioned intermediate product B in a 250ml three-necked flask, and adding a 0.8g palladium-carbon catalyst, after stirring and mixing, feed into nitrogen to replace the oxidizing gas in the three-necked flask, then vacuumize, feed into The hydrogen reduction reaction was carried out for 4 hours, and then the reduced material was filtered, the catalyst was filtered off, concentrated by rotary evaporation until a solid was precipitated, and then a large amount of precipitate was precipitated by adding water. After vacuum drying at 40°C, a product with a total molar yield of 78% and a purity of 98.5% was obtained.

Wherein the aminonitrobenzene has the following structural formula (1), and the carboxynaphthalene sulfonic acid has the following structural formula (2)

Embodiment 4 : This embodiment provides a kind of synthetic method of aminobenzimidazole naphthalenesulfonic acid compound, and it comprises the following steps:

(1) 0.1mol carboxylnaphthalene sulfonic acid and 0.2mol aminonitrobenzene are dissolved in 150g mass concentration is 86% polyphosphoric acid, prepare reaction solution;

(2) the reaction solution in the above-mentioned steps (1) is placed in the reactor, the temperature of the reactor is raised to 200 ° C, and reacted under nitrogen protection for 4 hours, then the material in the reactor is poured into a large amount of water to separate out solid, the precipitated solid is filtered to obtain intermediate product A; then intermediate product A is washed 3 times with 1 mol/L hydrochloric acid to obtain intermediate product B;

(3) adding 80ml DMAc stirring and dissolving to above-mentioned intermediate product B in a 250ml three-necked flask, and adding a 0.8g palladium-carbon catalyst, after stirring and mixing, feed into nitrogen to replace the oxidizing gas in the three-necked flask, then vacuumize, feed into The hydrogen reduction reaction was carried out for 4 hours, and then the reduced material was filtered, the catalyst was filtered off, concentrated by rotary evaporation until a solid was precipitated, and then a large amount of precipitate was precipitated by adding water. After vacuum drying at 40°C, a product with a total molar yield of 81% and a purity of 98.4% was obtained.

Wherein the aminonitrobenzene has the following structural formula (1), and the carboxynaphthalene sulfonic acid has the following structural formula (2)

Embodiment 5 : This embodiment provides a kind of synthetic method of aminobenzimidazole naphthalenesulfonic acid compound, and it comprises the following steps:

Dissolve 0.1 mol of carboxynaphthalene sulfonic acid (its structure is the same as that of structural formula (2) in Example 1) and 0.2 mol of aminobenzene (1,2,4-triaminobenzene, CAS: 615-71-4) in a mass of 100 g In polyphosphoric acid with a concentration of 86%, a reaction solution was prepared; the reaction solution in the above steps was placed in a reaction kettle, the temperature of the reaction kettle was raised to 200 ° C, and the reaction was carried out under nitrogen protection for 6 hours, and then the The material was poured into a large amount of water, a certain amount of solid appeared, the precipitated solid was filtered, and then the filter cake was washed three times with 1 mol/L hydrochloric acid, and then vacuum-dried at 40 ° C to obtain the aminobenzimidazolenaphthalenesulfonic acid compound , through NMR and infrared structural characterization, it is found that there are many components with different amino contents, not a single compound. The applicant speculates that the amino group at the 1, 2 position in the 1,2,4-triaminobenzene used and the carboxylnaphthalenesulfonic acid The carboxyl group in the acid reacts to obtain an aminobenzimidazolenaphthalenesulfonic acid compound containing a benzimidazole structure, and at the same time, the carboxyl group in the carboxylnaphthalenesulfonic acid reacts with the amino group on the 5th position to generate a product containing two amino groups in the structure, and other Cross-linked product formed by dehydration condensation between many amino groups and carboxyl groups.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the invention in other forms. Any person skilled in the art may use the technical contents disclosed above to make changes or change to equivalent embodiments with equivalent changes. However, any simple modifications made to the above embodiments according to the technical essence of the present invention, equivalent changes and modifications without departing from the content of the technical solutions of the present invention, still belong to the protection scope of the technical solutions of the present invention.

Claims (10)

1. A method for synthesizing aminobenzimidazole naphthalenesulfonic acid compound is characterized by comprising the following steps:

(1) dissolving 0.1mol of carboxyl naphthalene sulfonic acid and 0.15-0.25 mol of aminonitrobenzene in polyphosphoric acid to prepare 5-55 wt% solution;

(2) placing the reaction solution into a reaction kettle, raising the temperature of the reaction kettle to 180-200 ℃, reacting for 1.5-10 hours, adding water into the reaction kettle for precipitation, and filtering to obtain an intermediate product A; washing the intermediate product A with acid to obtain an intermediate product B;

(3) and dissolving the intermediate product B in an organic solvent, introducing hydrogen to reduce under the action of a catalyst, and carrying out post-treatment to obtain the aminobenzimidazole naphthalenesulfonic acid compound.

2. The method for synthesizing an aminobenzimidazole naphthalenesulfonic acid compound according to claim 1, wherein the catalyst in step (3) is a palladium on carbon catalyst.

3. The method for synthesizing an aminobenzimidazole naphthalenesulfonic acid compound according to claim 1, wherein the post-treatment in step (3) includes the steps of: and filtering the reduced material, removing the catalyst, concentrating until solid is separated out, adding water to separate out precipitate, leaching a filter cake obtained after filtering with ethanol, draining, and drying in vacuum at 35-55 ℃ to obtain the catalyst.

4. The method for synthesizing an aminobenzimidazole naphthalenesulfonic acid compound according to claim 1, wherein the acid in step (2) is hydrochloric acid, and the concentration thereof is 0.8 to 1.2 mol/L.

5. The method of synthesizing an aminobenzimidazole naphthalenesulfonic acid compound according to claim 1, wherein the aminonitrobenzene has the following structural formula:

wherein: r₁One selected from hydrogen atom, hydrocarbon group, carboxyl group, amino group, hydroxyl group, siloxane group and cyano group.

6. The method for synthesizing an aminobenzimidazole naphthalenesulfonic acid compound according to any one of claims 1 to 5, wherein the carboxynaphthalenesulfonic acid is a naphthalenesulfonate having a carboxyl group in its structure.

7. The method of synthesizing an aminobenzimidazole naphthalenesulfonic acid compound according to claim 6, wherein the carboxynaphthalenesulfonic acid has the following structure:

wherein: r₂、R₃、R₄Is a substituent; the substituent groups are respectively and independently selected from one of hydrogen atoms, alkyl groups, carboxyl groups, amino groups, hydroxyl groups, siloxane groups and cyano groups.

8. The method for synthesizing an aminobenzimidazole naphthalenesulfonic acid compound according to claim 7,wherein R is₃And R₄At least one of them is a carboxyl group.

9. The method of synthesizing an aminobenzimidazole naphthalenesulfonic acid compound according to claim 1, wherein the aminobenzimidazole naphthalenesulfonic acid compound has the following structural formula:

10. the application of the aminobenzimidazole naphthalenesulfonic acid compound synthesized by the method for synthesizing an aminobenzimidazole naphthalenesulfonic acid compound according to any one of claims 1 to 9 in the fields of polyamide and polyimide materials.