Carboxyl-containing Troger base and preparation method of anion exchange membrane of Troger base

Abstract

The invention discloses a carboxyl-containing Troger base and a preparation method of an anion exchange membrane of the carboxyl-containing Troger base, and relates to the technical field of ion exchange membrane preparation. The preparation method of the anion exchange membrane containing the carboxyl comprises the following steps: synthesizing a Troger base containing the carboxyl, synthesizing a polybenzimidazole polymer containing the Troger base, synthesizing an anion exchange membrane polymer containing the Troger base, and preparing the compact anion exchange membrane containing the Troger base. Compared with the prior art, the preparation method has the advantages that the carboxyl-containing Troger base is synthesized through the reaction of specific aminomethyl benzoic acid and dimethoxymethane and by using trifluoroacetic acid as a solvent and a catalyst, so that the purity and the stability of a product are improved, the carboxyl-containing Troger base is more effectively introduced into a polybenzimidazole polymer, and the polybenzimidazole polymer is prepared. The porosity of the polybenzimidazole polymer is improved, so that the electrochemical performance and the mechanical stability of the anion exchange membrane are improved.

Description

Technical Field

[0001] The invention relates to the technical field of ion exchange membrane preparation, in particular to a carboxyl-containing chogel base and a preparation method of an anion exchange membrane thereof. Background Art

[0002] As the core material of electrochemical energy conversion and storage devices such as fuel cells, flow batteries and electrolyzers, ion exchange membranes have broad application prospects in clean energy, energy conservation and emission reduction, energy conversion and storage. As a key component in energy conversion devices, ion exchange membranes must allow ions to migrate efficiently between the cathode and anode of the membrane. For anion exchange membranes (AEMs), they must have high ionic conductivity, high thermal stability, high mechanical stability, high chemical stability and high electrochemical stability under working conditions. At present, one of the main methods to improve conductivity is to increase the ion exchange capacity (IEC) of polymer membranes. However, with the increase in the number of cationic groups, the water absorption rate of AEMs will also increase, resulting in membrane swelling and reducing its mechanical stability and dimensional stability. At low ion exchange capacity, the extensive hydrophobic polymer matrix structure leads to tortuous or even disconnected ion conduction pathways, hindering or blocking ion movement pathways, resulting in a rapid decrease in ion conductivity. Therefore, how to efficiently organize the cationic groups in the membrane, construct effective anion transport channels, and promote the rapid transport of hydroxide ions has become the key to the industrial application of AEM membranes. Therefore, it is of great significance to design ion exchange membranes with low cost and high performance. Therefore, we propose a method for preparing a carboxyl-containing Chaogel base and anion exchange membrane thereof. Summary of the invention

[0003] The object of the present invention is to provide a method for preparing a carboxyl-containing chogel base and an anion exchange membrane thereof.

[0004] To achieve the above object, the present invention provides the following technical solution: a carboxyl-containing Chaugol base, comprising a carboxyl-containing Chaugol base, wherein the carboxyl-containing Chaugol base is prepared by reacting a specific aminomethylbenzoic acid and dimethoxymethane, wherein the methyl group and the carboxyl group have specific sites on the Chaugol base molecule, and the chemical structure of the carboxyl-containing Chaugol base is: ; The method for purifying the carboxyl-containing Chogar base includes adjusting the solution to a specific pH value after the polymerization is completed.

[0005] As a further embodiment of the present invention: the specific aminomethylbenzoic acid has any of the following monomer structures: ; The carboxyl-containing Chogel base uses trifluoroacetic acid as a solvent and a catalyst during the preparation process.

[0006] In addition, the present invention also provides a method for preparing a carboxyl-containing anion exchange membrane, comprising the following steps: Step 1, synthesizing the carboxyl-containing Choger's base, using trifluoroacetic acid as a solvent and a catalyst, mixing specific aminomethylbenzoic acid and dimethoxymethane according to a specific feed ratio, and performing a synthesis reaction to obtain the carboxyl-containing Choger's base; Step 2, synthesizing a polybenzimidazole polymer containing a choger base, using polyphosphoric acid and methanesulfonic acid as solvents, using phosphorus pentoxide as a dehydration condensation agent, mixing a rigid twisted phenyltetramine monomer, biphenyltetramine and a phthalic acid monomer according to a specific feed ratio, and performing a polymerization reaction to obtain a polybenzimidazole polymer containing a choger base; Step 3, synthesizing an anion exchange membrane polymer containing a choger base, using dimethyl sulfoxide as a solvent, mixing methyl iodide and a polybenzimidazole copolymer according to a specific feed ratio, and performing an ionization substitution reaction to obtain an anion exchange membrane polymer containing a choger base; Step 4: preparing a dense anion exchange membrane containing Chauger's base, mixing an anion exchange membrane polymer containing Chauger's base with a polar solvent to obtain a casting solution, and then forming a film of the casting solution on a substrate and drying it to obtain a dense anion exchange membrane containing Chauger's base.

[0007] As a further scheme of the present invention, in the step 1, the specific method for synthesizing the carboxyl-containing Chaoger base is: a specific aminomethylbenzoic acid and dimethoxymethane are mixed according to a feed ratio of m:1 to m:n, wherein 0<m<1, 0<n<1, cooled to -10°C to 5°C, dissolved for 0.1h to 3h, trifluoroacetic acid is added dropwise within 10min, and stirred at room temperature for 2h to 48h to obtain a transparent solution, slowly poured into a certain amount of deionized water under vigorous stirring, 1 mol / L sodium bicarbonate is added dropwise until a solid is produced, the solid solution is filtered out, washed with water and methanol until the filtrate is neutral, the product is collected, and dried in a vacuum oven at 80°C to 120°C for 12h to obtain the carboxyl-containing Chaoger base.

[0008] As a further scheme of the present invention, in the step 2, the specific method for synthesizing the polybenzimidazole polymer containing the Chauger base is: polyphosphoric acid, phosphorus pentoxide, rigid twisted phenyltetramine monomer and benzyltetramine are mixed according to a feed ratio of x:1 to x:y, wherein 0<x<1, 0<y<1, and the temperature is raised to 90℃~150℃ for dissolution for 2h~12h, and then the Chauger base containing carboxylic acid is added to obtain a homogeneous solution, and then the temperature is raised to 190℃~220℃ for reaction for 0.5h~12h to obtain the polybenzimidazole polymer containing the Chauger base.

[0009] As a further scheme of the present invention, in the step three, the specific method for synthesizing the anion exchange membrane polymer containing Chauger base is: using dimethyl sulfoxide as a solvent, methyl iodide and polybenzimidazole copolymer are mixed according to a feed ratio of a:b, wherein 0<a<10, 0<b<1, and the temperature is raised to 25℃~80℃ for reaction for 2h~48h to obtain anion exchange membrane polymer containing Chauger base.

[0010] As a further scheme of the present invention, in the step 4, the specific method of preparing a dense anion exchange membrane containing Chauger's base is: the casting liquid is formed into a film on a substrate by a casting method, and is dried at 40°C to 140°C for 0.5h to 72h to obtain a dense anion exchange membrane containing Chauger's base.

[0011] As a further embodiment of the present invention, in the step 2, the structure of the rigid twisted phenyltetramine monomer is shown in any one of the following formulas: ; The structure of the phthalic acid monomer is shown in any of the following formulas: ; There is a carboxyl group connected to each side of the benzene ring.

[0012] As a further embodiment of the present invention, the general chemical structure formula of the anion exchange membrane containing Chaoger base is: ; Wherein, n is 10 to 1000, * indicates a connection site, R3 is H and CH3, R4 is H and CH3, R1 includes any combination of a biphenyltetramine monomer group and a rigid twisted phenyltetramine monomer group, and the structural formula of the biphenyltetramine monomer group is: ; The rigid twisted phenyltetramine monomer group comprises at least one of the following structural formulas: ; R2 is an ionized Chaoger base structure, including at least one of the following structural formulas: ; in, To stabilize the anion.

[0013] By adopting the above technical solution, compared with the prior art, the beneficial effects of the present invention are: 1. The present invention synthesizes a carboxyl-containing Choger's base by reacting a specific aminomethylbenzoic acid with dimethoxymethane and using trifluoroacetic acid as a solvent and a catalyst, which not only improves the purity and stability of the product, but also enables the carboxyl-containing Choger's base to be more effectively introduced into the polybenzimidazole polymer, thereby increasing the porosity of the polybenzimidazole polymer, thereby improving the electrochemical performance and mechanical stability of the anion exchange membrane; 2. The present invention introduces rigid twisted phenyltetramine monomers and biphenyltetramine, combined with carboxyl-containing choger base, to synthesize a polybenzimidazole polymer with a specific structure. The polymer not only has a high porosity, but also maintains high mechanical strength, thereby optimizing the ion conduction pathway and improving the ion conductivity. In addition, by precisely controlling the feed ratio and reaction conditions, the structure and performance of the polymer can be further adjusted to meet the needs of different application scenarios; 3. The present invention can improve the mechanical stability and solubility of the ion exchange membrane by introducing the choger base unit into the polybenzimidazole main chain. This improvement not only enhances the durability of the membrane, but also optimizes its performance in different solvents, providing a wider compatibility for the application of ion exchange membranes in various electrochemical devices.

[0014] Other advantages, objectives and features of the present invention will be described in part in the following description, and in part will be apparent to those skilled in the art based on the following examination and study, and can be taught from the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the steps of the method for preparing an anion exchange membrane in an embodiment of the present invention. DETAILED DESCRIPTION

[0016] The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention.

[0017] In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0018] Please refer to the attached Figure 1 The present invention provides a carboxyl-containing Chaugol base, which is prepared by reacting a specific aminomethylbenzoic acid and dimethoxymethane, wherein the methyl group and the carboxyl group have specific positions on the Chaugol base molecule, and the chemical structure of the carboxyl-containing Chaugol base is: ; The method for purifying the carboxyl-containing Chogar base includes adjusting the solution to a specific pH value after the polymerization is completed.

[0019] In one embodiment of the present invention, the specific aminomethylbenzoic acid has any of the following monomer structures: ; The carboxyl-containing Chaogel base uses trifluoroacetic acid as a solvent and a catalyst during the preparation process.

[0020] The present invention also provides a method for preparing a carboxyl-containing anion exchange membrane, comprising the following steps: Step 1, synthesizing the carboxyl-containing Choger's base, using trifluoroacetic acid as a solvent and a catalyst, mixing specific aminomethylbenzoic acid and dimethoxymethane according to a specific feed ratio, and performing a synthesis reaction to obtain the carboxyl-containing Choger's base; Step 2, synthesizing a polybenzimidazole polymer containing a choger base, using polyphosphoric acid and methanesulfonic acid as solvents, using phosphorus pentoxide as a dehydration condensation agent, mixing a rigid twisted phenyltetramine monomer, biphenyltetramine and a phthalic acid monomer according to a specific feed ratio, and performing a polymerization reaction to obtain a polybenzimidazole polymer containing a choger base; Step 3, synthesizing an anion exchange membrane polymer containing a choger base, using dimethyl sulfoxide as a solvent, mixing methyl iodide and a polybenzimidazole copolymer according to a specific feed ratio, and performing an ionization substitution reaction to obtain an anion exchange membrane polymer containing a choger base; Step 4: preparing a dense anion exchange membrane containing chauger's base, mixing an anion exchange membrane polymer containing chauger's base with a polar solvent to obtain a casting solution, and then forming a film with the casting solution on a substrate and drying it to obtain a dense anion exchange membrane containing chauger's base.

[0021] In one embodiment of the present invention, the specific method for synthesizing the carboxyl-containing Chaoger base in step 1 is: a specific aminomethylbenzoic acid and dimethoxymethane are mixed according to a feed ratio of m:1 to m:n, wherein 0<m<1, 0<n<1, cooled to -10°C to 5°C, dissolved for 0.1h to 3h, trifluoroacetic acid is added dropwise within 10min, and stirred at room temperature for 2h to 48h to obtain a transparent solution, slowly poured into a certain amount of deionized water under vigorous stirring, 1 mol / L sodium bicarbonate is added dropwise until a solid is produced, the solid solution is filtered out, washed with water and methanol until the filtrate is neutral, the product is collected, and dried in a vacuum oven at 80°C to 120°C for 12h to obtain a carboxyl-containing Chaoger base.

[0022] In one embodiment of the present invention, in step 2, the specific method for synthesizing the polybenzimidazole polymer containing the Chauger base is to mix polyphosphoric acid, phosphorus pentoxide, rigid twisted phenyltetramine monomer and benzyltetramine according to a feed ratio of x:1 to x:y, wherein 0<x<1, 0<y<1, and heat to 90℃~150℃ for dissolution for 2h~12h, then add the Chauger base containing carboxylic acid to obtain a homogeneous solution, and then heat to 190℃~220℃ for reaction for 0.5h~12h to obtain the polybenzimidazole polymer containing the Chauger base.

[0023] In one embodiment of the present invention, the specific method for synthesizing the anion exchange membrane polymer containing Chauger base in step three is: using dimethyl sulfoxide as a solvent, mixing methyl iodide and polybenzimidazole copolymer according to a feed ratio of a:b, wherein 0<a<10, 0<b<1, heating to 25℃~80℃ and reacting for 2h~48h to obtain anion exchange membrane polymer containing Chauger base.

[0024] In one embodiment of the present invention, the specific method for preparing a dense anion exchange membrane containing Chauger's base in step 4 is: forming a film on a substrate by casting the casting liquid, and drying it at 40°C to 140°C for 0.5h to 72h to obtain a dense anion exchange membrane containing Chauger's base.

[0025] In one embodiment of the present invention, the structure of the rigid twisted phenyltetramine monomer in step 2 is shown in any one of the following formulas: ; The structure of the phthalic acid monomer is shown in any of the following formulas: ; There is a carboxyl group connected to each side of the benzene ring.

[0026] In one embodiment of the present invention, the general chemical structure of the anion exchange membrane containing Chaoger base is: ; Wherein, n is 10 to 1000, * indicates a connection site, R3 is H and CH3, R4 is H and CH3, R1 includes any combination of a biphenyltetramine monomer group and a rigid twisted phenyltetramine monomer group, and the structural formula of the biphenyltetramine monomer group is: ; The rigid twisted phenyltetramine monomer group comprises at least one of the following structural formulas: ; R2 is an ionized Chaoger base structure, including at least one of the following structural formulas: ; in, To stabilize the anion.

[0027] Example 1: Under nitrogen atmosphere, 3-amino-4-methylbenzoic acid (1.37 g, 10 mmol) was dissolved in dimethoxymethane (1.84 mL, 50 mmol) at room temperature. After complete dissolution, the temperature was lowered to 5°C for dissolution for 1 hour. An appropriate amount of trifluoroacetic acid (30 mL) was added dropwise within 10 minutes, and stirred at room temperature for 48 hours to obtain a transparent solution. A certain amount of deionized water was slowly poured into the solution under vigorous stirring, and 1 mol / L sodium bicarbonate was added dropwise until a large amount of solid was produced. The solid solution was filtered out and washed with water and methanol several times until the filtrate was neutral. The product was collected and dried in a vacuum oven at 80-120°C for 12 hours to obtain a carboxylic acid-containing Chaoger base, 4,10-dimethyl-6H,12H-5,11-aminodibenzo[b,f][1,5]diazo-1,7-dicarboxylic acid (TB1-COOH). 85% polyphosphoric acid was added to trifluoroacetic acid. In a three-necked flask, nitrogen is introduced to exclude oxygen, 3,3'-diaminobenzidine is added to the three-necked flask, the temperature is raised to 120°C to dissolve for 3 hours, and then 4,10-dimethyl-6H,12H-5,11-aminodibenzo[b,f][1,5]diazo-1,7-dicarboxylic acid (TB1-COOH) is added to make the total concentration of the monomers 15wt%. After obtaining a homogeneous solution, the temperature is raised to 200°C for reaction for 12 hours. When the reaction solution becomes very viscous and climbs the pole, the polymerization reaction is completed. The high-viscosity reaction solution is precipitated in water to obtain a filamentous polymer, which is neutralized with excess NaOH, washed with water for multiple times, and dried to obtain a solid polymer. The obtained solid polymer is placed in a round-bottomed single-necked flask, and N-methyl-2-pyrrolidone or dimethyl sulfoxide is used as a solvent. Methyl iodide and the polybenzimidazole polymer containing the choger base are mixed at a feed ratio of 10:1 to carry out an ionization substitution reaction; The reaction solution was precipitated in acetone by magnetic stirring at 60°C for 24 hours, and washed with acetone for multiple times. The precipitated polymer was dissolved and mixed with excess NaOH solution. The exchange of iodide ions and hydroxide ions was achieved by stirring the polymer. Finally, the polymer was precipitated, rinsed with water, and dried to obtain an anion exchange membrane polymer containing Chauger's base. The degree of ionization can be achieved by controlling the amount of iodomethane or the ionization time. The obtained polymer was dissolved in dimethyl sulfoxide to form a 3wt% transparent solution. The casting solution was cast on a glass plate and dried at 60°C for 24 hours to form a membrane. The membrane was immersed in a 1mol / L dilute sulfuric acid solution for 24 hours, and then immersed in deionized water and washed to neutrality to obtain an anion exchange membrane containing Chauger's base.

[0028] Example 2: Under nitrogen atmosphere, 4-amino-3-methylbenzoic acid (1.37 g, 10 mmol) was dissolved in dimethoxymethane (1.84 mL, 50 mmol) at room temperature. After complete dissolution, the temperature was lowered to 5°C for dissolution for 1 hour. An appropriate amount of trifluoroacetic acid (30 mL) was added dropwise within 10 minutes, and stirred at room temperature for 48 hours to obtain a transparent solution. A certain amount of deionized water was slowly poured into the solution under vigorous stirring, and 1 mol / L sodium bicarbonate was added dropwise until a large amount of solid was produced. The solid solution was filtered out and washed with water and methanol several times until the filtrate was neutral. The product was collected and dried in a vacuum oven at 80-120°C for 12 hours to obtain a carboxylic acid-containing Chaoger base, 4,10-dimethyl-6H,12H-5,11-aminodibenzo[b,f][1,5]diazo-2,8-dicarboxylic acid (TB2-COOH). 85% polyphosphoric acid was added to the solution. In a three-necked flask, nitrogen is introduced to exclude oxygen, 3,3'-diaminobenzidine is added to the three-necked flask, the temperature is raised to 120°C to dissolve for 3 hours, and then 4,10-dimethyl-6H,12H-5,11-aminodibenzo[b,f][1,5]diazo-2,8-dicarboxylic acid (TB2-COOH) is added to make the total concentration of the monomers 15wt%. After obtaining a homogeneous solution, the temperature is raised to 200°C for reaction for 12 hours. When the reaction solution becomes very viscous and climbs the pole, the polymerization reaction is completed. The high-viscosity reaction solution is precipitated in water to obtain a filamentous polymer, which is neutralized with excess NaOH, washed with water for multiple times, and dried to obtain a solid polymer. The obtained solid polymer is placed in a round-bottomed single-necked flask, and N-methyl-2-pyrrolidone or dimethyl sulfoxide is used as a solvent. Methyl iodide and a polybenzimidazole polymer containing a choger base are mixed at a feed ratio of 10:1 to carry out an ionization substitution reaction; The reaction solution was precipitated in acetone by magnetic stirring at 60°C for 24 hours, and washed with acetone for multiple times. The precipitated polymer was dissolved and mixed with excess NaOH solution. The exchange of iodide ions and hydroxide ions was achieved by stirring the polymer. Finally, the polymer was precipitated, rinsed with water, and dried to obtain an anion exchange membrane polymer containing Chauger's base. The degree of ionization can be achieved by controlling the amount of iodomethane or by controlling the ionization time. The obtained polymer was dissolved in dimethyl sulfoxide to form a 3wt% transparent solution. The casting solution was cast on a glass plate and dried at 60°C for 24 hours to form a film. The film was immersed in a 1mol / L dilute sulfuric acid solution for 24 hours, and then immersed in deionized water and washed until neutral to obtain a fluorene-based anion exchange membrane containing Chauger's base.

[0029] Example 3: Under nitrogen atmosphere, 3-amino-2-methylbenzoic acid (1.37 g, 10 mmol) was dissolved in dimethoxymethane (1.84 mL, 50 mmol) at room temperature. After complete dissolution, the temperature was lowered to 5°C for dissolution for 1 hour. An appropriate amount of trifluoroacetic acid (30 mL) was added dropwise within 10 minutes, and stirred at room temperature for 48 hours to obtain a transparent solution. A certain amount of deionized water was slowly poured into the solution under vigorous stirring, and 1 mol / L sodium bicarbonate was added dropwise until a large amount of solid was produced. The solid solution was filtered out and washed with water and methanol several times until the filtrate was neutral. The product was collected and dried in a vacuum oven at 80-120°C for 12 hours to obtain a carboxylic acid-containing Chaoger base, 4,10-dimethyl-6H,12H-5,11-aminodibenzo[b,f][1,5]diazo-3,9-dicarboxylic acid (TB3-COOH). 85% polyphosphoric acid was added to trifluoroacetic acid. In a three-necked flask, nitrogen is introduced to exclude oxygen, 3,3'-diaminobenzidine is added to the three-necked flask, the temperature is raised to 120°C to dissolve for 3 hours, and then 4,10-dimethyl-6H,12H-5,11-aminodibenzo[b,f][1,5]diazo-3,9-dicarboxylic acid (TB3-COOH) is added to make the total concentration of the monomers 15wt%. After obtaining a homogeneous solution, the temperature is raised to 200°C for reaction for 12 hours. When the reaction solution becomes very viscous and climbs the pole, the polymerization reaction is completed. The high-viscosity reaction solution is precipitated in water to obtain a filamentous polymer, which is neutralized with excess NaOH, washed with water for multiple times, and dried to obtain a solid polymer. The obtained solid polymer is placed in a round-bottomed single-necked flask, and N-methyl-2-pyrrolidone or dimethyl sulfoxide is used as a solvent. Methyl iodide and the polybenzimidazole polymer containing the choger base are mixed at a feed ratio of 10:1 to carry out an ionization substitution reaction; The reaction mixture was stirred magnetically at 60° C. for 24 hours, and the solution obtained by the reaction was precipitated in acetone, washed with acetone for multiple times, and the precipitated polymer was dissolved and mixed with an excess of NaOH solution. The polymer was stirred to achieve the exchange of iodide ions and hydroxide ions. Finally, the polymer was precipitated, rinsed with water, and dried to obtain an anion exchange membrane polymer containing a choger base. The degree of ionization can be achieved by controlling the amount of iodomethane or by controlling the ionization time. The obtained polymer was dissolved in dimethyl sulfoxide to form a 3wt% transparent solution. The casting solution was cast on a glass plate, dried at 60° C. for 24 hours to form a membrane, and the membrane was immersed in a 1mol / L dilute sulfuric acid solution for 24 hours, and then immersed in deionized water and washed until neutral to obtain a spirocyclic anion exchange membrane containing a choger base.

[0030] Example 4: Under a nitrogen atmosphere, 2-amino-5-methylbenzoic acid (1.37 g, 10 mmol) was dissolved in dimethoxymethane (1.84 mL, 50 mmol) at room temperature. After complete dissolution, the temperature was lowered to 5°C for dissolution for 1 hour. An appropriate amount of trifluoroacetic acid (30 mL) was added dropwise within 10 minutes, and stirred at room temperature for 48 hours to obtain a transparent solution. A certain amount of deionized water was slowly poured into the solution under vigorous stirring, and 1 mol / L sodium bicarbonate was added dropwise until a large amount of solid was produced. The solid solution was filtered out and washed with water and methanol several times until the filtrate was neutral. The product was collected and dried in a vacuum oven at 80 to 120°C for 12 hours to obtain a carboxylic acid-containing Chaoger base, 2,8-dimethyl-6H,12H-5,11-aminodibenzo[b,f][1,5]diazo-4,10-dicarboxylic acid (TB4-COOH). 85% polyphosphoric acid was added to the solution. In a three-necked flask, nitrogen is introduced to exclude oxygen, 3,3'-diaminobenzidine is added to the three-necked flask, the temperature is raised to 120°C to dissolve for 3 hours, and then 2,8-dimethyl-6H,12H-5,11-aminodibenzo[b,f][1,5]diazo-4,10-dicarboxylic acid (TB4-COOH) is added to make the total concentration of the monomers 15wt%. After obtaining a homogeneous solution, the temperature is raised to 200°C for reaction for 12 hours. When the reaction liquid becomes very viscous and climbs the pole, the polymerization reaction is completed. The high-viscosity reaction liquid is precipitated in water to obtain a filamentous polymer, which is neutralized with excess NaOH, washed with water for multiple times, and dried to obtain a solid polymer. The obtained solid polymer is placed in a round-bottomed single-necked flask, and N-methyl-2-pyrrolidone or dimethyl sulfoxide is used as a solvent. Methyl iodide and a polybenzimidazole polymer containing a choger base are mixed at a feed ratio of 10:1 to carry out an ionization substitution reaction; The reaction mixture was stirred magnetically at 60° C. for 24 hours, and the solution obtained by the reaction was precipitated in acetone, washed with acetone for multiple times, and the precipitated polymer was dissolved and mixed with an excess of NaOH solution. The polymer was stirred to achieve the exchange of iodide ions and hydroxide ions. Finally, the polymer was precipitated, rinsed with water, and dried to obtain an anion exchange membrane polymer containing a choger base. The degree of ionization can be achieved by controlling the amount of iodomethane or by controlling the ionization time. The obtained polymer was dissolved in dimethyl sulfoxide to form a 3wt% transparent solution. The casting solution was cast on a glass plate, dried at 60° C. for 24 hours to form a membrane, and the membrane was immersed in a 1mol / L dilute sulfuric acid solution for 24 hours, and then immersed in deionized water and washed until neutral to obtain a spirocyclic anion exchange membrane containing a choger base.

[0031] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments.

[0032] It is apparent to those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the invention, and the changes still fall within the protection scope of the invention.

Claims

1. A carboxyl-containing chaugol base, comprising a carboxyl-containing chaugol base, characterized in that: The carboxyl-containing Chaoger's base is prepared by reacting specific aminomethylbenzoic acid and dimethoxymethane, and the methyl group and the carboxyl group have specific positions on the Chaoger's base molecule. The chemical structure of the carboxyl-containing Chaoger's base is: ; The method for purifying the carboxyl-containing Chogar base includes adjusting the solution to a specific pH value after the polymerization is completed.

2. A carboxyl-containing chaugol base according to claim 1, characterized in that: The specific aminomethylbenzoic acid has any of the following monomer structures: ； The carboxyl-containing Chogel base uses trifluoroacetic acid as a solvent and a catalyst during the preparation process.

3. The method for preparing a carboxyl-containing anion exchange membrane for carboxyl-containing chogel alkali according to any one of claims 1 to 2, characterized in that: The following steps are involved: Step 1, synthesizing the carboxyl-containing Choger's base, using trifluoroacetic acid as a solvent and a catalyst, mixing specific aminomethylbenzoic acid and dimethoxymethane according to a specific feed ratio, and performing a synthesis reaction to obtain the carboxyl-containing Choger's base; Step 2, synthesizing a polybenzimidazole polymer containing a choger base, using polyphosphoric acid and methanesulfonic acid as solvents, using phosphorus pentoxide as a dehydration condensation agent, mixing a rigid twisted phenyltetramine monomer, biphenyltetramine and a phthalic acid monomer according to a specific feed ratio, and performing a polymerization reaction to obtain a polybenzimidazole polymer containing a choger base; Step 3, synthesizing an anion exchange membrane polymer containing a choger base, using dimethyl sulfoxide as a solvent, mixing methyl iodide and a polybenzimidazole copolymer according to a specific feed ratio, and performing an ionization substitution reaction to obtain an anion exchange membrane polymer containing a choger base; Step 4: preparing a dense anion exchange membrane containing Chauger's base, mixing an anion exchange membrane polymer containing Chauger's base with a polar solvent to obtain a casting solution, and then forming a film of the casting solution on a substrate and drying it to obtain a dense anion exchange membrane containing Chauger's base.

4. The method for preparing a carboxyl-containing anion exchange membrane according to claim 3, characterized in that: In the step 1, the specific method for synthesizing the carboxyl-containing Choger base is to mix a specific aminomethylbenzoic acid and dimethoxymethane according to a feed ratio of m:1 to m:n, wherein 0<m<1, 0<n<1, cool to -10°C to 5°C, dissolve for 0.1h to 3h, dropwise add trifluoroacetic acid within 10min, and stir at room temperature for 2h to 48h to obtain a transparent solution, slowly pour into a certain amount of deionized water under vigorous stirring, dropwise add 1 mol / L sodium bicarbonate until a solid is produced, filter out the solid solution, wash with water and methanol until the filtrate is neutral, collect the product, and dry it in a vacuum oven at 80°C to 120°C for 12h to obtain the carboxyl-containing Choger base.

5. The method for preparing a carboxyl-containing anion exchange membrane according to claim 3, characterized in that: In the step 2, the specific method for synthesizing the polybenzimidazole polymer containing the Chauger base is to mix polyphosphoric acid, phosphorus pentoxide, rigid twisted phenyltetramine monomer and benzyltetramine according to a feed ratio of x:1 to x:y, wherein 0<x<1, 0<y<1, and heat to 90℃~150℃ to dissolve for 2h~12h, then add the Chauger base containing carboxylic acid to obtain a homogeneous solution, and then heat to 190℃~220℃ to react for 0.5~12h to obtain the polybenzimidazole polymer containing the Chauger base.

6. The method for preparing a carboxyl-containing anion exchange membrane according to claim 3, characterized in that: In the step 3, the specific method for synthesizing the anion exchange membrane polymer containing Chauger's base is to use dimethyl sulfoxide as a solvent, mix methyl iodide and polybenzimidazole copolymer according to a feed ratio of a:b, wherein 0<a<10, 0<b<1, raise the temperature to 25℃~80℃ and react for 2h~48h to obtain the anion exchange membrane polymer containing Chauger's base.

7. The method for preparing a carboxyl group-containing anion exchange membrane according to claim 3, characterized in that: In the step 4, the specific method for preparing the dense anion exchange membrane containing Chauger's base is to form a film on a substrate by casting the casting solution, and dry it at 40° C. to 140° C. for 0.5 h to 72 h to obtain a dense anion exchange membrane containing Chauger's base.

8. The method for preparing a carboxyl-containing anion exchange membrane according to claim 3, characterized in that: In the step 2, the structure of the rigid twisted phenyltetramine monomer is shown in any one of the following formulas: ； The structure of the phthalic acid monomer is shown in any of the following formulas: ； There is a carboxyl group connected to each side of the benzene ring.

9. The method for preparing a carboxyl group-containing anion exchange membrane according to claim 3, characterized in that: The general chemical structure formula of the anion exchange membrane containing Chaoger base is: ； Wherein, n is 10 to 1000, * indicates a connection site, R3 is H and CH3, R4 is H and CH3, R1 includes any combination of a biphenyltetramine monomer group and a rigid twisted phenyltetramine monomer group, and the structural formula of the biphenyltetramine monomer group is: ； The rigid twisted phenyltetramine monomer group comprises at least one of the following structural formulas: ； R2 is an ionized Chaoger base structure, including at least one of the following structural formulas: ； in, To stabilize the anion.

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