Polycarbazolyl nitrogen-containing derivative, anion exchange membrane and preparation method and application of anion exchange membrane

Abstract

The invention discloses a polycarbazolyl nitrogen-containing derivative, an anion exchange membrane and a preparation method and application of the anion exchange membrane, and relates to the technical field of high-molecular compounds. The polycarbazolyl anion exchange membrane provided by the invention is a matrix and shows high stability, and 3-methyl-3, 6-diazol [5, 5]-6-ammonium bromide has a double quaternary ammonium cation structure and is grafted on the polycarbazolyl matrix, so that the conductivity of the membrane can be greatly improved. The anion-exchange membrane with a microphase separation structure and high ion exchange capacity is prepared by adopting a superacid catalytic polymerization method, and the prepared anion-exchange membrane has the characteristics of high ion exchange capacity, good alkali-resistant stability, simple method, easiness in industrialization and the like; the anion exchange membrane has important application value in the industries related to the hydrogen energy source field, such as alkaline fuel cells, water electrolysis hydrogen production, flow batteries, electrochemical ammonia synthesis and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer compounds, and particularly relates to a polycarbazole-based nitrogen-containing derivative, an anion exchange membrane, and a preparation method and application thereof. Background Art

[0002] As a key material in the field of hydrogen energy, alkaline anion exchange membranes have extensive applications in alkaline fuel cells, hydrogen production by electrolysis of water, CO2 reduction, electrochemical synthesis of ammonia, and flow batteries. The key factors determining their performance mainly include the following three: one is chemical stability, which directly determines the performance of the material; the second is mechanical stability, which mainly affects the durability of the membrane; the third is ionic conductivity, which directly affects the ionic conduction effect of the membrane material.

[0003] In terms of chemical stability, high chemical stability can improve the service life of anion exchange membranes under high-temperature and highly alkaline conditions. The chemical stability of anion exchange membranes mainly depends on the alkali stability of the polymer backbone and ionized groups. The current research on the backbone materials of anion exchange membranes in use mainly focuses on polyolefins, polyether ether ketones, polybenzimidazoles, and polybiphenyls. There are few reports on poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] anion exchange membranes containing 3-methyl-3,6-diazabicyclo[5,5]-6-bromonium ions. Superacid-catalyzed polymerization is used for the synthesis of such membranes. The prior art discloses the preparation of anion exchange membranes by superacid-catalyzed polymerization. Currently, a large number of studies have shown that the ether-free backbone structure prepared by superacid-catalyzed polymerization has relatively high chemical stability. In terms of mechanical stability, the mechanical stability of anion exchange membranes mainly depends on the rigidity of the polymer backbone, the flexibility of the side chains, and the degree of crosslinking. From the perspective of synthetic chemistry, the main challenges for anion exchange membranes are as follows: (1) high degree of polymerization of the polymer backbone; (2) introduction and grafting degree of side chains; (3) controllable and appropriate degree of crosslinking. For example, in the currently commonly used polyarylether-based anion exchange membranes, their synthesis is mainly through superacid-catalyzed polymerization. However, due to the relatively fast polymerization rate, it is easy to cause gelation and result in the inability to form a film; while for polyolefin-based anion exchange membranes, it is difficult to introduce side chains due to the limitations of polyolefin monomers. At the same time, in order to control the water absorption and swelling properties and phase separation structure of anion exchange membranes, it is a current development trend in the research field of anion exchange membranes to appropriately introduce hydrophobic chain segments and groups. In terms of ionic conductivity, an important role of anion exchange membranes is to transfer hydroxide ions. A high ion exchange capacity requires a high concentration of ionized groups per unit volume under the premise of a consistent conduction mechanism. Therefore, it has always been the goal of scientific researchers to prepare anion exchange membranes with high alkali stability, high ionic conductivity, and good mechanical properties through convenient and efficient synthesis methods. To achieve high ionic conductivity, it is necessary to develop new grafting methods to achieve a high grafting rate and to achieve the orderliness of ionized groups through controllable means. This is also an important challenge in the current research field of anion exchange membranes.

[0004] Currently, anion exchange membranes with quaternary ammonium salt ions such as N-methylpiperidine and quinine that have been reported have relatively good stability. However, their exchange capacity is not high and their conductivity is relatively low. Therefore, it is very necessary to explore new quaternary ammonium salt cations and develop new alkaline anion exchange membranes with excellent comprehensive properties. Summary of the Invention

[0005] Aiming at the deficiencies existing in the above-mentioned background technology, the present invention mainly solves the problems of low film conductivity and poor alkali resistance stability existing in the prior art. The present invention provides a polycarbazole-based nitrogen-containing derivative, an anion exchange membrane, and a preparation method and application thereof. This method uses an electrophilic substitution reaction to synthesize 3-methyl-3,6-diazole[5,5]-6-ammonium bromide, and then uses a superacid-catalyzed polymerization to efficiently prepare poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone]. Finally, a quaternization reaction is used to successfully prepare an anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] with 3-methyl-3,6-diazole[5,5]-6-ammonium bromide ions. The prepared polycarbazole-based anion exchange membrane as the matrix exhibits high stability, and 3-methyl-3,6-diazole[5,5]-6-ammonium bromide has a bis-quaternary ammonium cation structure, and grafting it onto the polycarbazole-based matrix can greatly improve the conductivity of the membrane.

[0006] The first object of the present invention is to provide a polycarbazole-based nitrogen-containing derivative, and the structural general formula of this derivative is as follows:

[0007] Among them, n = 300 - 350.

[0008] The second object of the present invention is to provide a preparation method of a polycarbazole-based nitrogen-containing derivative, including the following steps: Dissolve poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] in an organic solvent, then add 3-methyl-3,6-diazole[5,5]-6-ammonium bromide, and carry out a quaternization reaction to obtain the polycarbazole-based nitrogen-containing derivative; Among them, the temperature of the quaternization reaction is 65 - 75 °C, and the duration is 20 - 30 h; The molar ratio of the 3-methyl-3,6-diazole[5,5]-6-ammonium bromide to poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] is 1:1 - 5.

[0009] Preferably, the 3-methyl-3,6-diazole[5,5]-6-ammonium bromide is prepared according to the following steps: Add catalyst I to a dry Teflon sealed tube, then replace the nitrogen in the Teflon sealed tube 2 - 6 times through a double-row tube. Then add 1-methylpiperazine, 1,5-dibromopentane, and solvent I, seal the Teflon sealed tube, set the temperature to 80 - 100 °C, stir and react for 10 - 20 h, and then cool down to 10 - 30 °C to obtain a reaction solution; Add solvent II to the reaction solution for dilution, and then filter with diatomaceous earth to obtain a filtrate; The filtrate is successively concentrated and washed to obtain the 3-methyl-3,6-diazabicyclo[5,5]undec-6-ammonium bromide. Among them, the catalyst I is sodium sulfate, potassium sulfate, sodium carbonate or potassium carbonate; the solvent I is one or more of diethyl ether, methanol, ethanol, acetonitrile, and dichloromethane; the solvent II is one or more of ethanol, acetonitrile, and dichloromethane.

[0010] Preferably, the concentration of the catalyst I is 0.1 - 0.4 mol / L; the molar ratio of the catalyst I, 1-methylpiperazine, and 1,5-dibromopentane is 1 - 4:1:1.

[0011] Preferably, the poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] is prepared according to the following steps: Dissolve 9-(6-bromohexyl)-9H-carbazole in the solvent IV to obtain solution C; Add trifluoroacetone to solution C, continuously react in an ice bath for 10 - 30 min, then add catalyst II and catalyst III, continue to react in the ice bath for 10 - 60 min, and then remove the ice bath and place it at room temperature for reaction for 0.5 - 2 h to obtain solution D; Add the solvent IV to solution D for dilution, and add the diluted solution D to the solvent V for precipitation to obtain poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone]; Among them, the solvent IV is one or more of n-hexane, pyrrolidone, petroleum ether, and dichloromethane; the catalyst II is methanesulfonic acid or trifluoroacetic acid; the catalyst III is trifluoromethanesulfonic acid or trifluoroacetic acid; the solvent V is one or more of methanol, ethanol, and distilled water.

[0012] Preferably, the concentration of 9-(6-bromohexyl)-9H-carbazole in solution C is 1 - 2 mol / L; the molar ratio of the catalyst II, catalyst III, trifluoroacetone to 9-(6-bromohexyl)-9H-carbazole is 5 - 15:1 - 5:1 - 2:1. The third object of the present invention is to provide an application of a polycarbazole-based nitrogen-containing derivative in an ion exchange membrane.

[0013] The fourth object of the present invention is to provide an anion exchange membrane prepared by using a polycarbazole-based nitrogen-containing derivative.

[0014] The fifth object of the present invention is to provide a preparation method of an anion exchange membrane, comprising the following steps: Dissolve the polycarbazole-based nitrogen-containing derivative in the solvent VII to obtain solution G; Pour solution G onto a glass plate, and obtain the anion exchange membrane through film scraping and drying. Among them, the solvent VII is one or more of n-hexane, dimethyl sulfoxide, N,N-dimethylformamide, and dichloromethane.

[0015] The sixth object of the present invention is to provide an application of an anion exchange membrane in an alkaline fuel cell, hydrogen production by electrolysis of water, CO2 reduction, electrochemical synthesis of ammonia, or a flow battery.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention provides a polycarbazole-based nitrogen-containing derivative, an anion exchange membrane, and their preparation methods and applications. The polycarbazole-based nitrogen-containing derivative provided by the present invention is synthesized by an electrophilic substitution reaction to obtain 3-methyl-3,6-diazole [5,5]-6-ammonium bromide, and then poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] is efficiently prepared by polymerization catalyzed by a superacid, and finally obtained by a quaternization reaction. The anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] prepared from the polycarbazole-based nitrogen-containing derivative of the present invention has the following advantages: (1) high conductivity, which can reach 203 ms / cm at 80 °C, higher than most anion exchange membranes; (2) good dimensional stability, and the water absorption and swelling ratio at 80 °C is only 3.68%; (3) the alkali resistance of the anion exchange membrane is improved, and the membrane can still maintain 64% of the initial conductivity after being immersed in 2M NaOH solution for 120h.

[0017] The polycarbazole-based anion exchange membrane containing a nitrogen heterocyclic cation provided by the present invention has a structure similar to that of a bispiperidine cation for the nitrogen heterocyclic cation, thus greatly improving the conductivity of the anion exchange membrane and further improving the electrochemical performance of the anion exchange membrane. The main chain with alternating carbazole and trifluoroacetone is hydrophobic, and the 6-carbon alkyl side chains are hydrophilic, constructing a microphase separation structure, which is beneficial to the transport of OH - ions in the anion exchange membrane. The polycarbazole-based anion exchange membrane containing a nitrogen heterocyclic cation has high conductivity and good alkali resistance, and has good application prospects in the energy field. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 1H NMR spectrum of 9-(6-bromohexyl)-9H-carbazole (BHC).

[0019] Figure 2 1H NMR spectrum of [9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] polymer (PC-Br).

[0020] Figure 31H NMR spectrum of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] (QPC-DDMP) with 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ium bromide ion.

[0021] Figure 4 FT-IR spectrum of the anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] (QPC-DDMP) with 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ium bromide ion.

[0022] Figure 5 SAXS pattern of the anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] (QPC-DDMP) with 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ium bromide ion.

[0023] Figure 6 AFM image of the anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] (QPC-DDMP) with 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ium bromide ion.

[0024] Figure 7 Stress-strain curve of the anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] (QPC-DDMP) with 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ium bromide ion.

[0025] Figure 8 Tensile strength and elongation at break of the anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] (QPC-DDMP) with 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ium bromide ion.

[0026] Figure 9 Thermogravimetric curve of the anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] (QPC-DDMP) with 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ium bromide ion.

[0027] Figure 10 Conductivity of the anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] (QPC-DDMP) with 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ium bromide ion at different temperatures.

[0028] Figure 11Residual weight of the anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] (QPC-DDMP) with 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ium bromide ion treated in Fenton's reagent at 40 °C for different times.

[0029] Figure 12 Conductivity change of the anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] (QPC-DDMP) with 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ium bromide ion soaked in 2M NaOH solution at 80 °C for 120 h. Detailed implementation manners

[0030] In order to enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and drawings, but the specific embodiments cited do not limit the present invention.

[0031] The purpose of the present invention is to provide a polycarbazole-based nitrogen-containing derivative, an anion exchange membrane, and their preparation methods and applications, to improve the problems of low membrane conductivity and poor alkali resistance stability existing in the prior art.

[0032] In order to achieve the above purpose, the first aspect of the present invention provides a polycarbazole-based nitrogen-containing derivative, and the general structural formula of the derivative is as follows:

[0033] Among them, n = 300 - 350.

[0034] The polycarbazole-based nitrogen-containing derivative provided by the present invention is synthesized by reacting components 9-(6-bromohexyl)-9H-carbazole, trifluoroacetone, and a quaternary ammonium salt of a nitrogen-containing heterocycle; among them, the molar ratio of 9-(6-bromohexyl)-9H-carbazole to trifluoroacetone is 1:1 - 2; The molar ratio of the polymer obtained by copolymerizing 9-(6-bromohexyl)-9H-carbazole and trifluoroacetone to the quaternary ammonium salt of the nitrogen-containing heterocycle is 1:1 - 5.

[0035] The second aspect of the present invention provides a preparation method of a polycarbazole-based nitrogen-containing derivative, including the following steps: Dissolve poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] in an organic solvent, and then add 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ium bromide to carry out a quaternization reaction to obtain the polycarbazole-based nitrogen-containing derivative; Among them, the temperature of the quaternization reaction is 65 - 75 °C, and the duration is 20 - 30 h; The molar ratio of the 3-methyl-3,6-diazabicyclo[5,5]undec-6-ium bromide to the poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] is 1:1 to 5.

[0036] In one embodiment, a method for preparing a polycarbazole-based nitrogen-containing derivative specifically includes the following steps: Step 1: Weigh poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone], dissolve it in Solvent VI, and start stirring until the solution becomes clear and transparent to obtain Solution E. Among them, the concentration of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] is 0.10 - 0.30 mol / L; the Solvent VI can be one of n-hexane, petroleum ether, N,N-dimethylformamide, and dichloromethane; Step 2: Add 3-methyl-3,6-diazabicyclo[5,5]undec-6-ium bromide to Solution E for quaternization reaction, set the system temperature to 70 °C, and after reacting for 24 h, obtain Solution F; among them, the molar ratio of 3-methyl-3,6-diazabicyclo[5,5]undec-6-ium bromide to poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] is 1:1 to 5; Step 3: Pour Solution F into a mold and then place it in an oven for drying to obtain a pale yellow film, namely the polycarbazole-based nitrogen-containing derivative.

[0037] Among them, the 3-methyl-3,6-diazabicyclo[5,5]undec-6-ium bromide is prepared according to the following steps: Add Catalyst I to a dry Teflon-sealed tube, then displace nitrogen in the Teflon-sealed tube 2 - 6 times through a double-tube, and then add 1-methylpiperazine, 1,5-dibromopentane, and Solvent I. After sealing the Teflon-sealed tube, set the temperature to 80 - 100 °C, stir and react for 10 - 20 h, and then cool down to 10 - 30 °C to obtain a reaction solution; Add Solvent II to the reaction solution for dilution, and then filter it with diatomaceous earth to obtain a filtrate; Concentrate and wash the filtrate in sequence to obtain the 3-methyl-3,6-diazabicyclo[5,5]undec-6-ium bromide; Among them, the Catalyst I is sodium sulfate, potassium sulfate, sodium carbonate, or potassium carbonate; the Solvent I is one or more of ether, methanol, ethanol, acetonitrile, and dichloromethane; the Solvent II is one or more of ethanol, acetonitrile, and dichloromethane.

[0038] The concentration of the Catalyst I is 0.1 - 0.4 mol / L; the molar ratio of the Catalyst I, 1-methylpiperazine, and 1,5-dibromopentane is 1 - 4:1:1.

[0039] In one embodiment, a method for preparing 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ium bromide comprises the following steps: Step 1: Weigh catalyst I and add it to a dry Teflon-sealed tube. The catalyst I is sodium sulfate, potassium sulfate, sodium carbonate or potassium carbonate; Step 2: Replace the nitrogen in the Teflon-sealed tube 2 to 6 times through a double-tube; Step 3: Continuously add 1-methylpiperazine, 1,5-dibromopentane and solvent I to the Teflon-sealed tube to obtain solution A. Among them, the molar ratio of the added catalyst I, 1-methylpiperazine to 1,5-dibromopentane is 1 to 4:1:1; the solvent I can be one of ether, methanol, ethanol, acetonitrile, dichloromethane; the concentration of catalyst I is 0.1 to 0.4 mol / L; Step 4: After sealing the Teflon-sealed tube, set the system temperature to 80 to 100 °C, keep warm and stir the reaction for 10 to 20 h to obtain solution B; Step 5: After cooling the system to 10 to 30 °C, add solvent II to dilute solution B and filter with diatomaceous earth to obtain filtrate A; the solvent II can be one of ethanol, acetonitrile, dichloromethane; Step 6: Concentrate filtrate A to obtain a solid, wash it with solvent III, and filter to obtain the target compound, which is the white solid 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ium bromide. The solvent III can be one of petroleum ether, n-hexane.

[0040] Specifically, the poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] is prepared according to the following steps: Dissolve 9-(6-bromohexyl)-9H-carbazole in solvent IV to obtain solution C; Add trifluoroacetone to solution C, continuously react in an ice bath for 10 to 30 min, then add catalyst II and catalyst III, continue to react in the ice bath for 10 to 60 min, and then remove the ice bath and place it at room temperature for reaction for 0.5 to 2 h to obtain solution D; Add solvent IV to solution D for dilution, and add the diluted solution D to solvent V for precipitation to obtain poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone]; Among them, the solvent IV is one or more of n-hexane, pyrrolidone, petroleum ether, dichloromethane; the catalyst II is methanesulfonic acid or trifluoroacetic acid; the catalyst III is trifluoromethanesulfonic acid or trifluoroacetic acid; the solvent V is one or more of methanol, ethanol, distilled water.

[0041] The concentration of 9-(6-bromohexyl)-9H-carbazole in the solution C is 1 to 2 mol / L; the molar ratio of the catalyst II, catalyst III, trifluoroacetone to 9-(6-bromohexyl)-9H-carbazole is 5 to 15:1 to 5:1 to 2:1.

[0042] In one embodiment, a method for preparing poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] comprises the following steps: Step 1: Weigh 9-(6-bromohexyl)-9H-carbazole and dissolve it in solvent IV to obtain solution C. Among them, in solution C, the concentration of 9-(6-bromohexyl)-9H-carbazole is 1 to 2 mol / L; Step 2: Add solution C into a single-necked round-bottom flask placed in an ice bath and start stirring; Step 3: After stirring for 10 to 30 min, add trifluoroacetone thereto; Step 4: After continuously reacting in the ice bath for 10 to 30 min, slowly add catalyst II and catalyst III, wherein the molar ratio of catalyst II, catalyst III, trifluoroacetone to 9-(6-bromohexyl)-9H-carbazole is 5 to 15:1 to 5:1 to 2:1; Step 5: After continuing to react in the ice bath for 10 to 60 min, remove the ice bath, place the system at room temperature for reaction for 0.5 to 2 h, and obtain solution D; Step 6: Add solvent IV to solution D for dilution; Step 7: Drop the diluted solution D into solvent V for precipitation to obtain a white rubbery solid, which is dried under vacuum to obtain poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone].

[0043] Among them, the catalyst II can be methanesulfonic acid or trifluoroacetic acid; the catalyst III can be trifluoromethanesulfonic acid or trifluoroacetic acid; the solvent IV can be one of n-hexane, pyrrolidone, petroleum ether, dichloromethane; the solvent V can be one of methanol, ethanol, distilled water.

[0044] The third aspect of the present invention provides an application of a polycarbazole-based nitrogen-containing derivative in an ion exchange membrane.

[0045] The fourth aspect of the present invention provides an anion exchange membrane prepared from a polycarbazole-based nitrogen-containing derivative.

[0046] The fifth aspect of the present invention provides a method for preparing an anion exchange membrane, comprising the following steps: Dissolve the polycarbazole-based nitrogen-containing derivative in solvent VII to obtain solution G; Pour solution G onto a glass plate, and obtain the anion exchange membrane through film scraping and drying. Among them, solvent VII is one or more of n-hexane, dimethyl sulfoxide, N,N-dimethylformamide, and dichloromethane.

[0047] In one embodiment, a method for preparing an anion exchange membrane includes: Dissolve the polycarbazole-based nitrogen-containing derivative in solvent VII to obtain a clear and transparent solution G.

[0048] Pour solution G onto a glass plate, scrape the film and place it in an oven for drying to obtain an anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] containing 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ammonium bromide. Solvent VII is one of n-hexane, dimethyl sulfoxide, N,N-dimethylformamide, and dichloromethane.

[0049] The sixth aspect of the present invention provides an application of the anion exchange membrane in an alkaline fuel cell, hydrogen production by electrolysis of water, CO2 reduction, electrochemical synthesis of ammonia, or a flow battery.

[0050] The present invention uses superacid-catalyzed polymerization to prepare an anion exchange membrane with high ionic conductivity and high alkali stability. The ionic conductivity of the prepared anion exchange membrane can reach above 200 mS / cm at 80 °C, which is a high-ionic-conductivity anion exchange membrane.

[0051] It should be noted that the experimental methods used in the present invention are all conventional methods unless otherwise specified; the reagents and materials used can be purchased on the market unless otherwise specified.

[0052] Example 1 A method for preparing an anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] containing 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ammonium bromide includes: Step 1, weigh 0.33 g of sodium sulfate and add it to a dry Teflon sealed tube, and displace nitrogen 3 times through a double manifold. Subsequently, add 0.1 g of 1-methylpiperazine, 0.23 g of 1,5-dibromopentane, and 10 mL of diethyl ether in sequence. Then seal the Teflon sealed tube, set the system temperature to 80 °C, and keep stirring and reacting for 10 h. After cooling the system to 20 °C, add ethanol to dilute solution B, and filter with diatomaceous earth to obtain filtrate A. Concentrate filtrate A to obtain a solid, wash it with petroleum ether, and filter to obtain the target compound, 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ammonium bromide, as a white solid.

[0053] Step 2, Weigh 0.396 g of 9-(6-bromohexyl)-9H-carbazole, dissolve it in 0.8 mL of n-hexane to obtain Solution C. Add Solution C into a single-necked round-bottom flask placed in an ice bath, start stirring, and after stirring for 10 min, add 0.21 mL of trifluoroacetone thereto; after continuously reacting in the ice bath for 10 min, slowly add 0.39 mL of methanesulfonic acid and 0.21 mL of trifluoromethanesulfonic acid; after continuing to react in the ice bath for 10 min, remove the ice bath, place the system at room temperature for reaction for 0.5 h to obtain Solution D; add n-hexane to Solution D for dilution; drop the diluted Solution D into methanol for precipitation to obtain a white rubbery solid, and obtain poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] after vacuum drying.

[0054] Step 3, Weigh 0.32 g of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone], dissolve it in 7.5 mL of n-hexane, start stirring until the solution is clear and transparent to obtain Solution E. Add 0.127 g of 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide to Solution E for quaternization reaction, set the system temperature to 70 °C, and after reacting for 24 h, obtain Solution F; pour Solution F into a mold and then place it in an oven for drying to obtain a light yellow film; dissolve the obtained light yellow film in n-hexane until a clear and transparent solution G is obtained. Pour Solution G onto a glass plate, scrape the film and place it in an oven for drying to obtain an anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] containing 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide ions.

[0055] Example 2 A preparation method of an anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] containing 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide ions, comprising: Step 1, Weigh 0.35 g of potassium sulfate and add it to a dry Teflon sealed tube, and displace nitrogen 2 times through a double manifold. Subsequently, add 0.1 g of 1-methylpiperazine, 0.23 g of 1,5-dibromopentane and 10 mL of methanol in sequence. Then seal the Teflon sealed tube, set the system temperature to 90 °C, and keep stirring and reacting for 15 h. After cooling the system to 25 °C, add acetonitrile to dilute Solution B, and filter with diatomaceous earth to obtain Filtrate A. Concentrate Filtrate A to obtain a solid, wash it with n-hexane, and filter to obtain the target compound as a white solid of 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide.

[0056] Step 2: Weigh 0.264 g of 9-(6-bromohexyl)-9H-carbazole, dissolve it in 0.8 mL of pyrrolidone to obtain solution C. Add solution C into a single-necked round-bottom flask placed in an ice bath, and start stirring. After stirring for 20 min, add 0.07 mL of trifluoroacetone to it. After continuously reacting in the ice bath for 10 min, slowly add 0.26 mL of trifluoroacetic acid and 0.35 mL of trifluoromethanesulfonic acid. After continuing to react in the ice bath for 20 min, remove the ice bath, place the system at room temperature for reaction for 1 h to obtain solution D. Add pyrrolidone to solution D for dilution. Drop the diluted solution D into ethanol for precipitation to obtain a white rubbery solid, which is dried in vacuum to obtain poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone].

[0057] Step 3: Weigh 0.48 g of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone], dissolve it in 7.5 mL of n-hexane, start stirring until the solution is clear and transparent to obtain solution E. Add 0.38 g of 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide to solution E for quaternization reaction, set the system temperature to 70 °C, and after reacting for 24 h, obtain solution F. Pour solution F into a mold and then place it in an oven for drying to obtain a pale yellow film. Dissolve the obtained pale yellow film in dimethyl sulfoxide until a clear and transparent solution G is obtained. Pour solution G onto a glass plate, scrape the film and place it in an oven for drying to obtain an anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] containing 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide ions.

[0058] Example 3 A preparation method of an anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] containing 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide ions, comprising: Step 1: Weigh 0.33 g of sodium carbonate and add it to a dry Teflon sealed tube, and displace nitrogen 5 times through a double-tube. Subsequently, add 0.15 g of 1-methylpiperazine, 0.35 g of 1,5-dibromopentane and 10 mL of ethanol in sequence. Then seal the Teflon sealed tube, set the system temperature to 100 °C, and keep stirring and reacting for 16 h. After cooling the system to 22 °C, add dichloromethane to dilute solution B, and filter it with diatomaceous earth to obtain filtrate A. Concentrate filtrate A to obtain a solid, wash it with ether, and filter to obtain the target compound, 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide, as a white solid.

[0059] Step 2: Weigh 0.396 g of 9-(6-bromohexyl)-9H-carbazole, dissolve it in 0.8 mL of dichloromethane to obtain Solution C. Add Solution C into a single-necked round-bottom flask placed in an ice bath, and start stirring. After stirring for 10 min, add 0.21 mL of trifluoroacetone thereto. After continuously reacting in the ice bath for 20 min, slowly add 0.39 mL of methanesulfonic acid and 0.39 mL of trifluoroacetic acid. After continuing to react in the ice bath for 30 min, remove the ice bath, place the system at room temperature for reaction for 1 h to obtain Solution D. Add dichloromethane to Solution D for dilution. Drop the diluted Solution D into distilled water for precipitation to obtain a white rubber flake-like solid, which is dried in vacuo to obtain poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone].

[0060] Step 3: Weigh 0.64 g of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone], dissolve it in 7.5 mL of N,N-dimethylformamide, and start stirring until the solution is clear and transparent to obtain Solution E. Add 0.76 g of 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide to Solution E for quaternization reaction, set the system temperature to 70 °C, and react for 24 h to obtain Solution F. Pour Solution F into a mold and then place it in an oven for drying to obtain a pale yellow film. Dissolve the obtained pale yellow film in dimethyl sulfoxide until a clear and transparent Solution G is obtained. Pour Solution G onto a glass plate, scrape the film and place it in an oven for drying to obtain an anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] containing 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide ions.

[0061] Example 4 A preparation method of an anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] containing 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide ions, comprising: Step 1: Weigh 0.28 g of potassium carbonate and add it to a dry Teflon sealed tube, and displace nitrogen 4 times through a double-tube. Subsequently, add 0.1 g of 1-methylpiperazine, 0.23 g of 1,5-dibromopentane and 10 mL of acetonitrile in sequence. Then seal the Teflon sealed tube, set the system temperature to 90 °C, and keep stirring and reacting for 16 h. After cooling the system to 22 °C, add dichloromethane to dilute Solution B, and filter with diatomaceous earth to obtain Filtrate A. Concentrate Filtrate A to obtain a solid, wash it with ether, and filter to obtain the target compound as a white solid of 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide.

[0062] Step 2, Weigh 0.475 g of 9-(6-bromohexyl)-9H-carbazole, dissolve it in 0.8 mL of petroleum ether to obtain Solution C. Add Solution C into a single-necked round-bottom flask placed in an ice bath, and start stirring. After stirring for 30 min, add 2.58 mL of trifluoroacetone to it. After continuously reacting in the ice bath for 20 min, slowly add 9.33 mL of methanesulfonic acid and 6.37 mL of trifluoromethanesulfonic acid. After continuing to react in the ice bath for 40 min, remove the ice bath, place the system at room temperature for reaction for 1 h to obtain Solution D. Add dichloromethane to Solution D for dilution. Drop the diluted Solution D into methanol for precipitation to obtain a white rubbery solid, which is dried in vacuo to obtain poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone].

[0063] Step 3, Weigh 0.80 g of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone], dissolve it in 7.5 mL of dichloromethane, start stirring until the solution is clear and transparent to obtain Solution E. Add 1.268 g of 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide to Solution E for quaternization reaction, set the system temperature to 70 °C, and react for 24 h to obtain Solution F. Pour Solution F into a mold and place it in an oven for drying to obtain a pale yellow film. Dissolve the obtained pale yellow film in dichloromethane until a clear and transparent solution G is obtained. Pour Solution G onto a glass plate, scrape the film and place it in an oven for drying to obtain an anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] containing 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide ions.

[0064] Example 5 A preparation method of an anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] containing 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide ions, comprising: Step 1, Weigh 0.34 g of sodium sulfate and add it to a dry Teflon sealed tube, and displace nitrogen 6 times through a double manifold. Subsequently, add 0.2 g of 1-methylpiperazine, 0.46 g of 1,5-dibromopentane and 10 mL of dichloromethane in sequence. Then seal the Teflon sealed tube, set the system temperature to 90 °C, and keep stirring and reacting for 20 h. After cooling the system to 25 °C, add ethanol to dilute Solution B, and filter it with diatomaceous earth to obtain Filtrate A. Concentrate Filtrate A to obtain a solid, wash it with ether, and filter to obtain the target compound as a white solid 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide.

[0065] Step 2, Weigh 0.528 g of 9-(6-bromohexyl)-9H-carbazole and dissolve it in 0.8 mL of dichloromethane to obtain Solution C. Add Solution C into a single-necked round-bottom flask placed in an ice bath, and start stirring. After stirring for 30 min, add 0.29 mL of trifluoroacetone to it. After continuously reacting in the ice bath for 30 min, slowly add 1.55 mL of trifluoroacetic acid and 0.71 mL of trifluoromethanesulfonic acid. After continuing to react in the ice bath for 20 min, remove the ice bath, place the system at room temperature for reaction for 1.5 h to obtain Solution D. Add n-hexane to Solution D for dilution. Drop the diluted Solution D into ethanol for precipitation to obtain a white rubbery solid, which is dried in vacuo to obtain poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone].

[0066] Step 3, Weigh 0.96 g of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] and dissolve it in 7.5 mL of n-hexane. Start stirring until the solution is clear and transparent to obtain Solution E. Add 1.901 g of 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide to Solution E for quaternization reaction. Set the system temperature to 70 °C and react for 24 h to obtain Solution F. Pour Solution F into a mold and then place it in an oven for drying to obtain a pale yellow film. Dissolve the obtained pale yellow film in dimethyl sulfoxide to obtain a clear and transparent Solution G. Pour Solution G onto a glass plate, scrape the film and place it in an oven for drying to obtain an anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] containing 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide ions.

[0067] Example 6 A preparation method of an anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] containing 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide ions, comprising: Step 1, Weigh 0.28 g of potassium carbonate and add it to a dry Teflon sealed tube, and displace nitrogen 6 times through a double-tube. Subsequently, add 0.2 g of 1-methylpiperazine, 0.46 g of 1,5-dibromopentane and 10 mL of methanol in sequence. Then seal the Teflon sealed tube, set the system temperature to 80 °C, and keep stirring and reacting for 16 h. After cooling the system to 20 °C, add acetonitrile to dilute Solution B, and filter it with diatomaceous earth to obtain Filtrate A. Concentrate Filtrate A to obtain a solid, wash it with petroleum ether, and filter to obtain the target compound as a white solid, 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide.

[0068] Step 2: Weigh 0.396 g of 9-(6-bromohexyl)-9H-carbazole, dissolve it in 0.8 mL of pyrrolidone to obtain solution C. Add solution C into a single-necked round-bottom flask placed in an ice bath, and start stirring. After stirring for 10 min, add 0.21 mL of trifluoroacetone to it. After continuously reacting in the ice bath for 20 min, slowly add 0.39 mL of methanesulfonic acid and 0.21 mL of trifluoromethanesulfonic acid. After continuing to react in the ice bath for 20 min, remove the ice bath, place the system at room temperature for reaction for 0.5 h to obtain solution D. Add dichloromethane to solution D for dilution. Drop the diluted solution D into ethanol for precipitation to obtain a white rubbery solid, which is dried in vacuo to obtain poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone].

[0069] Step 3: Weigh 0.38 g of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone], dissolve it in 7.5 mL of dichloromethane, start stirring until the solution is clear and transparent to obtain solution E. Add 0.228 g of 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide to solution E for quaternization reaction, set the system temperature to 70 °C, and react for 24 h to obtain solution F. Pour solution F into a mold and then place it in an oven for drying to obtain a light yellow film. Dissolve the obtained light yellow film in n-hexane until a clear and transparent solution G is obtained. Pour solution G onto a glass plate, scrape the film and place it in an oven for drying to obtain a poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] anion exchange membrane containing 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide ions.

[0070] Example 7 A method for preparing a poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] anion exchange membrane containing 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide ions, comprising: Step 1: Weigh 0.25 g of sodium carbonate and add it to a dry Teflon-sealed tube, and displace nitrogen 4 times through a double-tube. Subsequently, add 0.2 g of 1-methylpiperazine, 0.46 g of 1,5-dibromopentane and 10 mL of dichloromethane in sequence. Then seal the Teflon-sealed tube, set the system temperature to 90 °C, and keep stirring and reacting for 20 h. After cooling the system to 22 °C, add ethanol to dilute solution B, and filter it with diatomaceous earth to obtain filtrate A. Concentrate filtrate A to obtain a solid, wash it with petroleum ether, and filter to obtain the target compound as a white solid 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide.

[0071] Step 2: Weigh 0.528 g of 9-(6-bromohexyl)-9H-carbazole and dissolve it in 0.8 mL of n-hexane to obtain Solution C. Add Solution C into a single-necked round-bottom flask placed in an ice bath, and start stirring. After stirring for 30 min, add 0.14 mL of trifluoroacetone to it. After reacting in the ice bath for 30 min, slowly add 1.55 mL of trifluoroacetic acid and 0.71 mL of trifluoromethanesulfonic acid. After continuing to react in the ice bath for 40 min, remove the ice bath, place the system at room temperature for reaction for 1 h to obtain Solution D. Add petroleum ether to Solution D for dilution. Drop the diluted Solution D into distilled water for precipitation to obtain a white rubbery solid, which is dried under vacuum to obtain poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone].

[0072] Step 3: Weigh 0.57 g of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] and dissolve it in 7.5 mL of N,N-dimethylformamide. Start stirring until the solution becomes clear and transparent to obtain Solution E. Add 0.456 g of 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide to Solution E for quaternization reaction. Set the system temperature to 70 °C and react for 24 h to obtain Solution F. Pour Solution F into a mold and then place it in an oven for drying to obtain a pale yellow film. Dissolve the obtained pale yellow film in n-hexane until a clear and transparent solution G is obtained. Pour Solution G onto a glass plate, scrape the film and place it in an oven for drying to obtain an anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] containing 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide ions.

[0073] To illustrate the relevant properties of the anion exchange membrane provided by the present invention, it is described in conjunction with the accompanying drawings.

[0074] Figure 1 1H NMR spectrum of 9-(6-bromohexyl)-9H-carbazole (BHC). Figure 1 1H NMR spectrum of the monomer 9-(6-bromohexyl)-9H-carbazole, a non-example sample. From Figure 1 the chemical shifts of the proton assignments, the chemical structure of 9-(6-bromohexyl)-9H-carbazole can be seen. The chemical shifts of the corresponding peaks for protons 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 are 8.02, 7.38, 7.31, 7.15, 4.21, 3.26, 1.80, 1.71, 1.38, and 1.30 ppm, respectively.

[0075] Figure 2 1H NMR spectrum of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] (PC-Br).Figure 2 For the sample data of Example 6 Figure 2 In Figure 2 , the chemical shift assignments of each proton of PC-Br in DMF-d7 to a, b, c, d, i, j, (e,h), (f,g) correspond to the peak positions of 8.43, 7.56, 7.33, 4.51, 2.72, 2.17, 1.77–1.69, 1.41–1.33 ppm respectively, which can prove that the PC-Br polymer was successfully prepared in the present invention.

[0076] Figure 3 1H NMR spectrum of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] (QPC-DDMP) of 3-methyl-3,6-diazabicyclo[5,5]-6-bromoammonium ion Figure 3 For the sample data of Example 6 Figure 3 In Figure 3 , the chemical shift assignments of each proton of QPC-DDMP in DMSO-d6 to a’, b’, c’, d’, k, i’, j’, (e’,h’), (l,m), (f’,g’) correspond to the peak positions of 8.33, 7.55, 7.16, 4.28, 3.93-3.71, 3.23, 2.11, 1.75-1.63, 1.54-1.49, 1.39-1.22 ppm respectively, which can prove that the QPC-DDMP polymer thin film was successfully prepared in the present invention.

[0077] Figure 4 Fourier transform infrared spectrum of anion exchange membranes of 9-(6-bromohexyl)-9H-carbazole (BHC), poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] (PC-Br), and poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] of 3-methyl-3,6-diazabicyclo[5,5]-6-bromoammonium ion (QPC-DDMP) Figure 4 For the sample data of Example 6 Figure 4 In Figure 4 , 2857 cm -1 corresponds to the stretching vibration peak of methylene, 1607 cm -1 , 1489 cm -1 corresponds to the vibration absorption of C=C on the carbazole aromatic ring skeleton, 1138 cm -1 The peak at is attributed to the C-F absorption peak, and the peak at 803 cm -1 is attributed to the out-of-plane bending vibration of =C-H on the carbazole aromatic ring, which can prove that the PC-Br polymer and QPC-DDMP polymer thin film were successfully prepared in the present invention.

[0078] Figure 5SAXS pattern of the anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] (QPC-DDMP) with 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ium bromide ions. Figure 5 For the sample data of Example 6, the distribution of hydrophilic and hydrophobic segments in the anion exchange membrane constitutes a microphase separation structure, and the microphase separation structure is conducive to the formation of ion channels. The hydrophilic-hydrophobic microphase separation structure of the anion exchange membrane can be further analyzed and characterized by small-angle X-ray diffraction (SAXs) and atomic force microscopy (AFM). As Figure 5 can be seen from the small-angle X-ray diffraction curve shown, there are obvious diffraction peaks in the QPC-DDMP membrane, and the scattering intensities of QPC-DDMP are 0.26 nm -1 , indicating that there is a microphase separation structure formed by the aggregation of ion clusters in the QPC-DDMP membrane. According to the Bragg formula d = 2π / q max , the domain spacing of ion clusters in the QPC-DDMP membrane is calculated to be 24 nm.

[0079] Figure 6 AFM image of the anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] (QPC-DDMP) with 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ium bromide ions. Figure 6 For the sample data of Example 6, as Figure 6 , analyzed by AFM, the microphase separation structure of the anion exchange membrane can be seen by observing the topography image. The black part is the hydrophobic region, and the brown part is the hydrophilic region. It can also be clearly seen the microphase separation structure of the anion exchange membrane, and this result corroborates with the SAXS result. From the above description, it can be seen that the QPC-DDMP membrane has a good microphase separation structure. The good microphase separation structure of the QPC-DDMP membrane is mainly determined by the difference in chain arrangement between the rigid aromatic main chain and the flexible aliphatic side chain. The rigid and bent main chain structure constitutes the hydrophobic segment, and the ion-conducting groups on the flexible side chain effectively aggregate to form the hydrophilic segment, ultimately forming an obvious microphase separation structure.

[0080] Figure 7 Stress-strain curve of the anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] (QPC-DDMP) with 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ium bromide ions. Figure 8 Tensile strength and elongation at break diagram of the anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] (QPC-DDMP) with 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ium bromide ions; Figure 7 and Figure 8All are sample data of Example 6. During the use of the anion exchange membrane, good mechanical properties need to be maintained, otherwise it will affect the service life of the device. The mechanical properties of QPC-DDMP are as Figures 7 - 8 shown. The tensile strength of the QPC-DDMP membrane is 14.3 MPa respectively, and the elongation at break is 12.2%. The rigid main chain structure and flexible side chain structure in the QPC-DDMP membrane enable it to achieve good mechanical properties.

[0081] Figure 9 Thermogravimetric curve of the anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] (QPC-DDMP) with 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ium bromide ions. Figure 9 All are sample data of Example 6. Since the working condition temperature of the anion exchange membrane in the hydrogen energy field is high (60 - 80 °C), the thermal stability of the AEM should be focused on during long-term use. The thermogravimetric curve of the polymer thin film of QPC-DDMP is as Figure 9 shown. The initial degradation temperature of the QPC-DDMP membrane is greater than 180 °C, which is much higher than the actual use temperature of the anion exchange membrane, indicating that the prepared QPC-DDMP membrane has good thermal stability and great application potential in the hydrogen energy field. The thermogravimetric loss of the QPC-DDMP membrane mainly has three stages. The first weight loss stage near 30 - 180 °C corresponds to the evaporation of bound water and residual solvents in the membrane. The weight loss between 180 °C and 380 °C is due to the degradation of the side chain structure and cationic groups. The last degradation stage after 380 °C is mainly the degradation of the poly(carbazole-co-trifluoroacetone) main chain.

[0082] Figure 10 Conductivity of the anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] (QPC-DDMP) with 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ium bromide ions at different temperatures. Figure 10 All are sample data of Example 6. As Figure 10 shown, the conductivity of the QPC-DDMP membrane increases with the increase of temperature. At 80 °C, the conductivity of QPC-DDMP is the highest, reaching 203 mS / cm, which proves that the QPC-DDMP membrane has good electrochemical properties in the hydrogen energy field.

[0083] Figure 11 Remaining weight of the anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] (QPC-DDMP) with 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ium bromide ions treated in Fenton's reagent at 40 °C for different times. Figure 11For the sample data of Example 6, the QPC-DDMP membrane was immersed in Fenton's reagent for oxidation stability testing. After 168 hours, the QPC-DDMP membrane could maintain 93.1% of its initial weight, indicating that the QPC-DDMP membrane has good oxidation stability performance.

[0084] Figure 12 The conductivity change of the anion exchange membrane of poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] (QPC-DDMP) with 3-methyl-3,6-diazabicyclo[5,5]-6-bromonium ion in 2M NaOH solution at 80 °C for 120 h. Figure 12 For the sample data of Example 6, the hydroxide ion conductivity of QPC-DDMP showed that it could maintain 44.3% of its initial conductivity after the accelerated alkali resistance experiment.

[0085] In summary, the present invention provides an anion exchange membrane containing poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] with 3-methyl-3,6-diazabicyclo[5,5]-6-bromonium ion. Using the prepared polycarbazole-based anion exchange membrane as the matrix, it exhibits high stability and the 3-methyl-3,6-diazabicyclo[5,5]-6-bromonium has a bisquaternary ammonium cation structure, which can greatly improve the conductivity of the membrane when grafted onto the polycarbazole-based matrix. The present invention uses a method of superacid-catalyzed polymerization to prepare a high ion exchange capacity anion exchange membrane with a microphase separation structure. The prepared anion exchange membrane has a high ion exchange capacity, good alkali resistance stability, and the method is simple and easy to industrialize. This kind of anion exchange membrane has important application value in industries related to the hydrogen energy field such as alkaline fuel cells, hydrogen production by electrolysis of water, flow batteries, and electrochemical synthesis of ammonia.

Claims

1. A polycarbazole-based nitrogen-containing derivative, characterized in that, The general structural formula of the derivative is as follows: Among them, n = 300 - 350.

2. The preparation method of the polycarbazole-based nitrogen-containing derivative according to claim 1, characterized in that, It includes the following steps: Dissolve poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] in an organic solvent, then add 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide, and carry out quaternization reaction to obtain the nitrogen-containing polycarbazole derivative; Among them, the temperature of the quaternization reaction is 65 - 75 °C, and the duration is 20 - 30 h; The molar ratio of the 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide to the poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] is 1:1 - 5.

3. The preparation method of the polycarbazole-based nitrogen-containing derivative according to claim 2, characterized in that, The 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide is prepared according to the following steps: Add catalyst I into a dry Teflon sealed tube, then displace nitrogen in the Teflon sealed tube 2 - 6 times through a double-tube, and then add 1-methylpiperazine, 1,5-dibromopentane and solvent I, seal the Teflon sealed tube, set the temperature to 80 - 100 °C, stir and react for 10 - 20 h, then cool down to 10 - 30 °C to obtain a reaction solution; Add solvent II to the reaction solution for dilution, and then filter with diatomite to obtain a filtrate; Concentrate and wash the filtrate in sequence to obtain the 3-methyl-3,6-diazabicyclo[5.5.0]undec-6-ene bromide; Among them, the catalyst I is sodium sulfate, potassium sulfate, sodium carbonate or potassium carbonate; the solvent I is one or more of ether, methanol, ethanol, acetonitrile, dichloromethane; the solvent II is one or more of ethanol, acetonitrile, dichloromethane.

4. The preparation method of the polycarbazole-based nitrogen-containing derivative according to claim 3, wherein, The concentration of the catalyst I is 0.1 - 0.4 mol / L; the molar ratio of the catalyst I, 1-methylpiperazine and 1,5-dibromopentane is 1 - 4:1:

1.

5. The preparation method of the polycarbazole-based nitrogen-containing derivative according to claim 2, wherein, The poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone] is prepared according to the following steps: Dissolve 9-(6-bromohexyl)-9H-carbazole in solvent IV to obtain solution C; Add trifluoroacetone to solution C, continuously react in an ice bath for 10 - 30 min, then add catalyst II and catalyst III, continue to react in the ice bath for 10 - 60 min, then remove the ice bath and place it at room temperature for reaction for 0.5 - 2 h to obtain solution D; Add solvent IV to solution D for dilution, and add the diluted solution D to solvent V for precipitation to obtain poly[9-(6-bromohexyl)-9H-carbazole-co-trifluoroacetone]; Among them, the solvent IV is one or more of n-hexane, pyrrolidone, petroleum ether, dichloromethane; the catalyst II is methanesulfonic acid or trifluoroacetic acid; the catalyst III is trifluoromethanesulfonic acid or trifluoroacetic acid; the solvent V is one or more of methanol, ethanol, distilled water.

6. The preparation method of the polycarbazole-based nitrogen-containing derivative according to claim 5, characterized in that, The concentration of 9-(6-bromohexyl)-9H-carbazole in solution C is 1 - 2 mol / L; the molar ratio of the catalyst II, catalyst III, trifluoroacetone to 9-(6-bromohexyl)-9H-carbazole is 5 - 15:1 - 5:1 - 2:

1.

7. Use of the polycarbazole-based nitrogen-containing derivative described in claim 1 in an ion exchange membrane.

8. An anion exchange membrane, characterized in that, Prepared by using the polycarbazole-based nitrogen-containing derivative described in claim 1.

9. A method for preparing an anion exchange membrane, characterized in that, Comprising the following steps: Dissolve the polycarbazole-based nitrogen-containing derivative in solvent VII to obtain solution G; Pour solution G onto a glass plate, and after scraping and drying, an anion exchange membrane is obtained; Wherein, solvent VII is one or more of n-hexane, dimethyl sulfoxide, N,N-dimethylformamide, and dichloromethane.

10. Use of the anion exchange membrane described in claim 9 in an alkaline fuel cell, hydrogen production by electrolysis of water, CO2 reduction, electrochemical synthesis of ammonia, or a flow battery.

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