Epoxy-terminated bipyridine biquaternary ammonium salt compound as well as preparation method and application thereof

Abstract

The invention relates to the technical field of chemical raw material preparation, and discloses an epoxy-terminated bipyridine biquaternary ammonium salt compound as well as a preparation method and application thereof. The epoxy-terminated bipyridine biquaternary ammonium salt compound has a structure as shown in a formula I, wherein R1 and R2 are respectively and independently alkylene of C1-C3; x is F, Cl or Br. The epoxy-terminated dipyridyl biquaternary ammonium salt simultaneously contains epoxy groups, dipyridyl and quaternary ammonium salt structures, and the compound prepared by the combination can be used as a modifier to perform positive charge modification on other materials, so that the positive charge property of the modified material is improved.

Description

Technical Field

[0001] This invention relates to the field of chemical raw material preparation technology, specifically to an epoxy-terminated bipyridine bisquaternary ammonium salt compound, its preparation method, and its application. Background Technology

[0002] 4,4'-Bipyridine is a crystalline solid, soluble in water and many types of organic solvents. Its crystals exhibit a planar dimer structure with π-π conjugation between molecules, which helps improve the chemical stability of the monomer. Compared to the benzene ring, the pyridine ring has a weaker conjugation effect, providing a more loosely conjugated structure, which can reduce flux loss in separation membrane applications. Furthermore, the two nitrogen atoms in 4,4'-bipyridine can undergo quaternization to form a bisquaternary ammonium salt with a high positive charge density, significantly improving the positive charge of materials as a polymer monomer or surface modifier. Positively charged separation membranes have wide applications, such as lithium extraction from salt lakes, water softening, electroplating wastewater treatment, and pervaporation. In addition, 4,4'-bipyridine is a bidentate chelating ligand that can form complexes with many types of metal ions, facilitating high-precision ion separation.

[0003] Epoxy groups can react with functional groups such as amino and hydroxyl groups, and are widely used in polymer preparation and surface modification. Besides their application in separation membranes, epoxy quaternary ammonium salts are also used in cosmetics, detergents, papermaking, paints, and coatings industries.

[0004] Therefore, the epoxy-terminated bipyridine bis-quaternary ammonium salt disclosed in this invention has broad application value. Summary of the Invention

[0005] The purpose of this invention is to overcome the problem of low positive charge of materials in the prior art, and to provide an epoxy-terminated bipyridine bis-quaternary ammonium salt compound, its preparation method and application. The epoxy-terminated bipyridine bis-quaternary ammonium salt contains epoxy groups, bipyridine and quaternary ammonium salt structures. The compound prepared by the above combination can be used as a modifier to positively modify other materials and improve the positive charge of the modified materials.

[0006] To achieve the above objectives, the first aspect of the present invention provides an epoxy-terminated bipyridine bis-quaternary ammonium salt compound, wherein the compound has the structure shown in Formula I;

[0007]

[0008] Wherein, R1 and R2 are each independently C1-C3 alkylene groups; X is F, Cl or Br.

[0009] A second aspect of the present invention provides a method for preparing the above-mentioned epoxy-terminated bipyridine bis-quaternary ammonium salt, wherein the method comprises:

[0010] (1) After mixing 4,4'-bipyridine, at least one compound of Formula 1 and a first organic solvent, a first reaction is carried out, and after solid-liquid separation and drying, the compound of Formula 2 is obtained.

[0011] (2) In the presence of the first catalyst and the second organic solvent, the compound shown in Formula 2 is mixed with the sulfonyl chloride compound in the second reaction, and after the first extraction and drying, the compound shown in Formula 3 is obtained.

[0012] (3) In the presence of a third organic solvent, the compound shown in Formula 3 is mixed with the second catalyst in a third reaction, and after quenching, second extraction, drying and purification, the quaternary ammonium salt shown in Formula I is obtained.

[0013]

[0014]

[0015] In this context, R, R1, and R2 are each independently C1-C3 alkylene groups; X is F, Cl, or Br; and R3, R4, R5, R6, and R7 are each independently H, methyl, tert-butyl, or dodecyl.

[0016] A third aspect of the present invention provides the application of the above-mentioned epoxy-terminated bipyridine quaternary ammonium salt compound in the preparation of separation membranes or functional material precursors.

[0017] Through the above technical solutions, the epoxy-terminated bipyridine quaternary ammonium salt, its preparation method, and its application provided by the present invention achieve the following beneficial effects:

[0018] (1) The epoxy-terminated bipyridine quaternary ammonium salt prepared by the present invention includes epoxy groups, bipyridine and quaternary ammonium salt structure. The bisepoxy groups can serve as active sites for participating in chemical reactions, the bisquaternary ammonium salt groups can effectively improve the positive charge of the material, and the pyridine structure can form complexes with various metal ions, further providing sites for charge modification and crosslinking degree adjustment. The compound prepared by the above combination can be used as a modifier to positively modify other materials.

[0019] (2) The preparation method of epoxy-terminated bipyridine bis-quaternary ammonium salt provided by the present invention has a simple reaction process and mild reaction conditions, and is suitable for mass production. Attached Figure Description

[0020] Figure 1 This is the infrared spectrum of product N1 from Example 1.

[0021] Figure 2 This is the NMR spectrum of product N1 from Example 1. Detailed Implementation

[0022] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0023] The first aspect of the present invention provides an epoxy-terminated bipyridine bisquaternary ammonium salt compound, wherein the compound has the structure shown in Formula I;

[0024]

[0025] Wherein, R1 and R2 are each independently C1-C3 alkylene groups; X is F, Cl or Br.

[0026] In this invention, the epoxy-terminated bipyridine bis-quaternary ammonium salt compound simultaneously comprises an epoxy group, a positive quaternary ammonium salt group, and a pyridine structure. The compound prepared through this combination can be used as a modifier to positively modify other materials. Specifically, in interfacial polymerization applications, the biepoxy functional group in the compound can serve as an active site participating in chemical reactions, the bis-quaternary ammonium salt effectively improves the positive charge of the polymer material, and the pyridine structure can form complexes with various metal ions, further providing sites for charge modification and crosslinking degree adjustment. Therefore, it can be used to prepare high-throughput, anti-fouling ion separation membranes. This compound exhibits strong functionality and has broad application prospects in industries such as cosmetics, detergents, papermaking, paints, and coatings, especially in the field of membrane separation.

[0027] In one specific embodiment of the present invention, R1 and R2 are methylene groups.

[0028] In one specific embodiment of the present invention, X is Cl or Br.

[0029] A second aspect of the present invention provides a method for preparing the above-mentioned epoxy-terminated bipyridine bis-quaternary ammonium salt, wherein the method comprises:

[0030] (1) After mixing 4,4'-bipyridine, at least one compound of Formula 1 and a first organic solvent, a first reaction is carried out, and after solid-liquid separation and drying, the compound of Formula 2 is obtained.

[0031] (2) In the presence of the first catalyst and the second organic solvent, the compound shown in Formula 2 is mixed with the sulfonyl chloride compound in the second reaction, and after the first extraction and drying, the compound shown in Formula 3 is obtained.

[0032] (3) In the presence of a third organic solvent, the compound shown in Formula 3 is mixed with the second catalyst in a third reaction, and after quenching, second extraction, drying and purification, the quaternary ammonium salt shown in Formula I is obtained.

[0033]

[0034] In this context, R, R1, and R2 are each independently C1-C3 alkylene groups; X is F, Cl, or Br; and R3, R4, R5, R6, and R7 are each independently H, methyl, tert-butyl, or dodecyl.

[0035] In this invention, the epoxy-terminated bipyridine quaternary ammonium salt compound prepared according to the above method includes an epoxy group, bipyridine, and a quaternary ammonium salt structure. The epoxy group can serve as an active site participating in chemical reactions, the bipyridine structure can form complexes with various metal ions, and the bis-quaternary ammonium salt group effectively improves the positive charge of the polymer material. Specifically, in the presence of a catalyst, 4,4'-bipyridine reacts with the compound shown in Formula 1 to generate the compound shown in Formula 2, and its conversion rate is high. The intermediate shown in Formula 2 reacts with a sulfonyl chloride compound, and further reacts with a second catalyst to obtain a quaternary ammonium salt with bis-epoxy groups at both ends, and the epoxy conversion rate is increased.

[0036] In one specific embodiment of the present invention, R, R1, and R2 are methylene groups.

[0037] In one specific embodiment of the present invention, X is Cl or Br.

[0038] In one specific embodiment of the present invention, R3, R4, R6, and R7 are H, and R5 is methyl.

[0039] In one specific embodiment of the present invention, the compound shown in Formula 1 is 3-bromo-1,2-bisphenol, i.e., R is methylene.

[0040] In one specific embodiment of the present invention, the compound shown in Formula 2 is 1,1'-bis(2,3-dihydroxypropyl)-[4,4'-bipyridine]-1,1'-bisonium bromide, i.e., R1 and R2 are methylene groups and X is Br.

[0041] In one specific embodiment of the present invention, the compound shown in Formula 3 is 1,1'-bis(2-hydroxy-3-(toluenesulfonyloxy)propyl)-[4,4'-bipyridine]-1,1'-diimide bromide, i.e., R1 and R2 are methylene groups and X is Br.

[0042] According to the present invention, the molar ratio of 4,4'-bipyridine to the compound shown in Formula 1 is 1:1.8-2.2.

[0043] In this invention, when the molar ratio of 4,4'-bipyridine to the compound shown in Formula 1 satisfies the above-mentioned range, it enables sufficient reaction between 4,4'-bipyridine and the compound shown in Formula 1, and improves the conversion rate of the final target product, the epoxy-terminated bipyridine bisquaternary ammonium salt compound.

[0044] Furthermore, the molar ratio of 4,4'-bipyridine to the compound shown in Formula 1 is 1:1.9-2.1.

[0045] According to the present invention, the mixing temperature of the first mixture is 50-75°C.

[0046] In this invention, when the mixing temperature of the first mixture meets the above-mentioned range, 4,4'-bipyridine and the compound shown in Formula 1 can be rapidly dissolved, thereby making them uniformly stirred and fully mixed.

[0047] Furthermore, the mixing temperature of the first mixture is 60-70°C.

[0048] According to the present invention, the conditions for the first reaction include: a reaction temperature of 50°C-75°C and a reaction time of 6-36 hours.

[0049] In this invention, when the conditions of the first reaction meet the above-mentioned range, the quaternization reaction of 4,4'-bipyridine with the compound shown in Formula 1 can be fully carried out, and the conversion rate of the final target product, epoxy-terminated bipyridine bisquaternary ammonium salt compound, can be improved.

[0050] Furthermore, the conditions for the first reaction include: a reaction temperature of 60-70℃ and a reaction time of 12-24h.

[0051] In this invention, there is no particular limitation on the method of solid-liquid separation, as long as solid-liquid separation can be achieved, such as filtration. In this invention, the compound represented by Formula 2 is separated from the product after the first reaction through solid-liquid separation.

[0052] In this invention, step (1) further includes washing the solid product after solid-liquid separation. Preferably, ethyl acetate and diethyl ether are used to wash the solid product. This preferred embodiment is beneficial for removing unreacted monomers and minimizing the loss of quaternary ammonium salts.

[0053] More preferably, the volume ratio of ethyl acetate to diethyl ether is 0.8-1.3:1.

[0054] In this invention, the drying conditions in step (1) are not particularly limited, and drying can be carried out under conventional conditions in the art, such as vacuum drying. Preferably, the vacuum drying time is 1-8 hours and the temperature is 40-80°C.

[0055] According to the present invention, the first catalyst is selected from at least one of triethylamine, N,N-dimethylcyclohexylamine, diethylamine and triphenylamine.

[0056] In this invention, when the type of the first catalyst meets the above-mentioned range, the compound shown in Formula 2 can react fully with the sulfonyl chloride compound, thereby improving the epoxy conversion rate of the final product.

[0057] Furthermore, the catalyst is triethylamine.

[0058] According to the present invention, the molar ratio of the first catalyst to the compound shown in Formula 2 is 1-5:1.

[0059] In this invention, when the molar ratio of the first catalyst to the compound shown in Formula 2 satisfies the above-mentioned range, the second reaction can achieve high catalytic efficiency with a low amount of catalyst.

[0060] Furthermore, the molar ratio of the first catalyst to the compound shown in Formula 2 is preferably 2-4:1.

[0061] According to the present invention, the sulfonyl chloride compound is selected from at least one of benzenesulfonyl chloride, p-toluenesulfonyl chloride, 3-tert-butylbenzenesulfonyl chloride, 2,5-dimethylbenzenesulfonyl chloride and p-dodecylbenzenesulfonyl chloride.

[0062] Furthermore, the sulfonyl chloride compound is p-toluenesulfonyl chloride.

[0063] According to the present invention, the molar ratio of the compound of Formula 2 to the sulfonyl chloride compound is 1:1.5-5.

[0064] In this invention, when the molar ratio of the compound of Formula 2 to the sulfonyl chloride compound meets the above-mentioned range, it can ensure that the sulfonyl chloride compound reacts more fully with the compound of Formula 2, thereby improving the epoxy conversion rate of the final product.

[0065] Furthermore, the molar ratio of the compound of Formula 2 to the sulfonyl chloride compound is 1:1.8-4.

[0066] According to the present invention, the conditions for the second reaction include: a reaction temperature of 5-40°C and a reaction time of 6-24 hours.

[0067] In this invention, when the conditions of the second reaction meet the above-mentioned range, solvent evaporation can be reduced while ensuring that the reaction proceeds fully, thus ensuring that the final product of subsequent epoxidation has a high epoxy conversion rate.

[0068] Furthermore, the conditions for the second reaction include: a reaction temperature of 15-30°C and a reaction time of 8-16 hours.

[0069] In this invention, the compound represented by Formula 3 is separated from the product after the second reaction by a first extraction.

[0070] In this invention, there is no particular limitation on the type of extractant used in the first extraction; it can be a conventional extractant in the art, such as anhydrous dichloromethane. There is also no particular limitation on the amount of extractant used, as long as the reaction product is completely extracted.

[0071] In this invention, before extraction in step (2), the reaction product is further diluted, preferably using water. There is no particular limitation on the amount of diluent used, as long as it can sufficiently dilute the reaction solution, for example, it can be 5 times or more the volume of the reaction solution.

[0072] In this invention, step (2) further includes washing the organic extract obtained from the first extraction, preferably using brine.

[0073] In this invention, there is no particular limitation on the type of brine, and it can be any of the commonly used solutions in the art, preferably a saturated sodium chloride solution. There is also no particular limitation on the amount of washing solution used, as long as it is sufficient to wash away unreacted monomers without causing significant loss of reactants.

[0074] According to the present invention, the second catalyst is selected from at least one of sodium hydride, cesium carbonate, and sodium carbonate.

[0075] In this invention, when the type of the second catalyst meets the above-mentioned range, it is beneficial to make the compound shown in Formula 3 undergo a more complete epoxidation reaction, so that the final product has a higher epoxidation conversion rate.

[0076] Furthermore, the catalyst is sodium hydride.

[0077] According to the present invention, the molar ratio of the compound represented by Formula 3 to the second catalyst is 1:1-4.

[0078] In this invention, when the molar ratio of the compound shown in Formula 3 to the second catalyst satisfies the above-mentioned range, the compound shown in Formula 3 can fully react with the second catalyst, resulting in high catalytic efficiency and economy.

[0079] Furthermore, the molar ratio of the compound represented by Formula 3 to the second catalyst is 1:2-3.

[0080] According to the present invention, the second mixing and the third mixing are each carried out independently under ice bath conditions. This preferred embodiment helps to reduce the intensity of the initial reaction and allows the reaction to proceed stably.

[0081] According to the present invention, the time for the second mixing and the third mixing is each independently 10-60 min.

[0082] In this invention, when the time for the second mixing and the third mixing meets the above-mentioned range, it can ensure that the reactants in the second mixing and the third mixing are mixed evenly, thereby improving the reaction efficiency.

[0083] According to the present invention, the conditions for the third reaction include: a reaction temperature of 5-40°C and a reaction time of 6-20 h.

[0084] In this invention, when the conditions of the third reaction meet the above-mentioned range, solvent evaporation in the third reaction can be reduced, the compound shown in Formula 3 can be fully reacted with the second catalyst, and the epoxy conversion rate of the final product can be improved.

[0085] Furthermore, the conditions for the third reaction include: a reaction temperature of 15-30°C and a reaction time of 8-16 hours.

[0086] In this invention, the temperature of the ice bath is -2°C to 5°C.

[0087] In this invention, the quenching is not particularly limited, and conventional methods in the art can be used for quenching, such as adding conventional quenching agents in the art, such as water.

[0088] In this invention, the quaternary ammonium salt represented by Formula I is separated from the product after the third reaction by a second extraction.

[0089] In this invention, in step (3), there is no particular limitation on the type of extractant used for the second extraction; it can be a conventional extractant in the art, such as diethyl ether. There is also no particular limitation on the amount of extractant used, as long as the reaction product is completely extracted.

[0090] In this invention, there are no particular limitations on the drying method in steps (2) and (3), and it can be a conventional drying method in the art, such as drying with anhydrous Na2SO4.

[0091] In this invention, steps (2) and (3) further include solute / solvent separation of the dried solution. The method of solute / solvent separation of the dried solution is not particularly limited; conventional separation methods in the art, such as rotary evaporation, can be used. In this invention, the solvent in the extracted organic extract is removed through solute / solvent separation.

[0092] In this invention, the third mixing and the third reaction are carried out under the protection of a protective gas. There is no particular limitation on the type of protective gas, which can be a protective gas commonly used in the art, preferably at least one of nitrogen, helium, argon and helium, and more preferably nitrogen.

[0093] According to the present invention, the first organic solvent, the second organic solvent and the third organic solvent are each independently selected from at least one of acetonitrile, dichloromethane, N,N-dimethylformamide and N,N-dimethylacetamide.

[0094] In this invention, there are no special requirements for the amounts of the first solvent, the second solvent, and the third solvent, as long as they can be fully dissolved and mixed evenly with the compound shown in Formula 1, the compound shown in Formula 2 and the sulfonyl chloride compound, and the second catalyst and the compound shown in Formula 3, respectively.

[0095] In this invention, the first organic solvent, the second organic solvent, and the third organic solvent are selected according to the different properties of reactants and products. Preferably, the first organic solvent, the second organic solvent, and the third organic solvent are different.

[0096] According to the present invention, the purification is carried out in a chromatography column.

[0097] According to the present invention, the eluent for purification is a mixture of ethyl acetate and petroleum ether, wherein the volume ratio of ethyl acetate to petroleum ether is 0.05-0.25:1.

[0098] In this invention, when the specific type of eluent mentioned above is selected and the volume ratio of ethyl acetate to petroleum ether in the eluent is controlled to meet the above range, a high elution efficiency is achieved.

[0099] In this invention, TLC is used to monitor whether the reaction is complete. This preferred embodiment is beneficial for controlling the degree of reaction and improving efficiency.

[0100] In this invention, the yield of the epoxy-terminated bipyridine bis-quaternary ammonium salt compound represented by Formula I is calculated using the following formula:

[0101] Yield = m1 / m2 × 100%, where m1 is the mass of the quaternary ammonium salt compound and m2 is the mass corresponding to the molar amount of the product calculated according to theory.

[0102] In this invention, the conversion rate of the epoxy-terminated bipyridine bis-quaternary ammonium salt compound quaternary ammonium salt represented by Formula I is determined by the following method:

[0103] Accurately weigh the dried product sample into a 250 mL Erlenmeyer flask, dissolve it in 20 mL of 10% ethanol solution, then add 5 drops of 10% KCrO aqueous solution as an indicator. Titrate with 0.05 mol / L AgNO3 standard solution until a brick-red color is reached (while shaking). Perform three parallel determinations and record the volume of AgNO3 standard solution consumed. Calculate the quaternary ammonium salt conversion rate x using the following formula:

[0104]

[0105] Where C is the concentration of silver nitrate standard solution (mol / L); V is the volume of AgNO3 standard solution consumed by the sample (mL); M is the theoretical molar mass of the tested sample (determined by combining the reaction raw materials, infrared spectrum and NMR spectrum to determine the product) (g / mol); and m is the mass of the sample (g).

[0106] In this invention, the epoxy conversion rate of the epoxy-terminated bipyridine bis-quaternary ammonium salt compound represented by Formula I is determined by the following method:

[0107] (1) Take 550 mL of anhydrous glacial acetic acid, add 8.2 mL of perchloric acid (72%) and shake well. Slowly add 24 mL of acetic anhydride to a beaker, stirring constantly with a glass rod. After cooling to room temperature, transfer to a 1000 mL volumetric flask, add anhydrous glacial acetic acid to dilute to the mark, shake well, and let stand for 24 hours to allow the acetic anhydride to fully react with the water in the solution, thus obtaining a perchloric acid-glacial acetic acid standard solution with a concentration of about 0.1 mol / L.

[0108] (2) Accurately weigh approximately 0.4 g (accurate to 0.0001 g) of potassium hydrogen phthalate dried to constant weight at 105℃ and place it in an Erlenmeyer flask. Add 20 mL of anhydrous glacial acetic acid to dissolve it. Add 1-2 drops of 0.5% crystalline glacial acetic acid solution and titrate with perchloric acid-glacial acetic acid standard solution until blue. Correct the titration result with a blank test (i.e., without adding potassium hydrogen phthalate). Calculate the concentration of the perchloric acid-glacial acetic acid standard solution to be C.

[0109] (3) Dissolve 100g of tetraethylammonium bromide in 400mL of glacial acetic acid to obtain tetraethylammonium bromide reagent.

[0110] (4) Weigh an appropriate amount of the synthesized sample, dissolve it in 10 mL of chloroform, add 10 mL of tetrabutylammonium bromide reagent and 1-2 drops of crystal violet indicator, titrate with a perchloric acid-glacial acetic acid standard solution of concentration C until the endpoint is dark green, record the volume of perchloric acid-glacial acetic acid standard solution consumed V, and perform a blank titration at the same time, consuming the volume of perchloric acid-glacial acetic acid standard solution V0.

[0111] Formula for calculating epoxy conversion rate:

[0112]

[0113] Wherein: E is the epoxy conversion rate of the product (%), V is the volume of perchloric acid-glacial acetic acid standard solution consumed by the sample (mL), V0 is the volume of perchloric acid-glacial acetic acid standard solution consumed by the blank titration (mL), C is the concentration of perchloric acid-glacial acetic acid standard solution (mol / L), m is the mass of the sample (g), and M is the theoretical molar mass of the tested sample (g / mol).

[0114] A third aspect of the present invention provides the application of the above-mentioned epoxy-terminated bipyridine quaternary ammonium salt compound in the preparation of separation membranes or functional material precursors.

[0115] The present invention will be described in detail below through embodiments.

[0116] In the following examples and comparative examples:

[0117] All raw materials used in the examples and comparative examples are commercially available products.

[0118] Example 1

[0119] (1) 32 mmol of 4,4'-bipyridine was dissolved in 50 mL of acetonitrile, and then 64 mmol of 3-bromo-1,2-bisphenol was added dropwise to the solution with stirring at 65 °C. The reaction mixture was stirred continuously for 16 hours. After the reaction was complete (monitored by TLC), it was cooled to room temperature. A large amount of solid precipitated out. The product was filtered, and the filter cake was washed three times with 25 mL of ethyl acetate and 25 mL of diethyl ether, respectively. The solid was removed and dried under vacuum at 60 °C for 1 hour to give the compound shown in Formula 2, wherein R1 and R2 are methylene groups and X is Br. The molar ratio of 4,4'-bipyridine to 3-bromo-1,2-bisphenol was 1:2.

[0120] (2) At 0 °C, 25 mmol of the compound of formula 2 obtained in step (1) was dissolved in 100 mL of anhydrous dichloromethane, and 90 mmol of triethylamine was added. 50 mmol of p-toluenesulfonyl chloride was added to the solution, and the reaction mixture was stirred at room temperature for 12 h. The reaction mixture was diluted with 500 mL of water and extracted three times (100 mL each time) with anhydrous dichloromethane. The combined organic extracts were washed with brine (saturated sodium chloride solution), dried over anhydrous Na2SO4, and concentrated under reduced pressure to give the compound of formula 3, wherein R1 and R2 are methylene groups, and X is Br. The molar ratio of the compound of formula 2 to p-toluenesulfonyl chloride is 1:2.

[0121] (3) At 0 °C, 15 mmol of the compound of formula 3 obtained in step (2) was dissolved in 120 mL of N,N-dimethylformamide, and 30 mmol of sodium hydride was added in portions. Under N2 protection, the mixture was stirred at 25 °C for 12 h. After complete conversion was observed by TLC, the reaction was quenched by adding water, and the aqueous layer was extracted three times with diethyl ether (50 mL each time). The combined organic layers were dried with Na2SO4, the solvent was distilled off under reduced pressure, and the crude product was purified on silica gel with a mixture of ethyl acetate / petroleum ether at a volume ratio of 1:20 to obtain 5.9 g (13.8 mmol) of reddish-brown solid epoxidized product, namely the epoxy-terminated bipyridine bis-quaternary ammonium salt compound N1 of formula I, where R1 and R2 are methylene groups and X is Br. The yield was 92%, the quaternary ammonium salt conversion was 93%, and the epoxy conversion was 93%. The molar ratio of the compound of formula 3 to sodium hydride was 1:2.

[0122] Figure 1 This is the infrared spectrum of product N1, 1388-1548 cm⁻¹. -1 The characteristic peak of quaternary ammonium salt appeared in the range, at 936 cm⁻¹. -1 Characteristic peaks of epoxides appeared nearby, at 1636 cm⁻¹. -1 The presence of a characteristic peak of bipyridine nearby, combined with the feed amount, indicates that 4,4'-bipyridine, 3-bromo-1,2-diol, and p-toluenesulfonyl chloride have successfully reacted to obtain the quaternary ammonium salt shown in Formula I, where R1 and R2 are methylene groups and X is Br.

[0123] Figure 2 The NMR spectrum of product N1 is shown below. 1 H-NMR (DMSO-d6, 600MH) Z )δ: 8.74(d,4H)(a), 7.77(d,4H)(b), 3.41-3.7(d,4H)(C), 3.25(q,2H)(d), 2.5-3(d,4H)(e).

[0124] Example 2

[0125] The phrase in step (3), "Dissolve 15 mmol of the compound shown in Formula 3 obtained in step (2) in 120 mL of N,N-dimethylformamide, add 30 mmol of sodium hydride in portions, protect with N2, and stir at 25°C for 12 h," is changed to "Dissolve 15 mmol of the compound shown in Formula 3 obtained in step (2) in 120 mL of N,N-dimethylformamide, add 37.5 mmol of sodium hydride in portions, protect with N2, and stir at 25°C for 12 h." Step (3) yields an epoxy-terminated bipyridine bis-quaternary ammonium salt compound, designated N2, with a yield of 93%, a quaternary ammonium salt conversion rate of 92%, and an epoxy conversion rate of 95%. The molar ratio of the compound shown in Formula 3 to sodium hydride is 1:2.5.

[0126] Example 3

[0127] In step (3), the statement "15 mmol of the compound shown in Formula 3 obtained in step (2) was dissolved in 120 mL of N,N-dimethylformamide, and 30 mmol of sodium hydride was added in portions. Under N2 protection, the mixture was stirred at 25°C for 12 h" was changed to "15 mmol of the compound shown in Formula 3 obtained in step (2) was dissolved in 120 mL of N,N-dimethylformamide, and 45 mmol of sodium hydride was added in portions. Under N2 protection, the mixture was stirred at 25°C for 12 h." Step (3) yielded an epoxy-terminated bipyridine bis-quaternary ammonium salt compound, designated N3, with a yield of 90%, a quaternary ammonium salt conversion rate of 93%, and an epoxy conversion rate of 95%. The molar ratio of the compound shown in Formula 3 to sodium hydride was 1:3.

[0128] Example 4

[0129] The phrase in step (3), "Dissolve 15 mmol of the compound shown in Formula 3 obtained in step (2) in 120 mL of N,N-dimethylformamide, add 30 mmol of sodium hydride in portions, protect with N2, and stir at 25°C for 12 h," is changed to "Dissolve 15 mmol of the compound shown in Formula 3 obtained in step (2) in 120 mL of N,N-dimethylformamide, add 30 mmol of sodium hydride in portions, protect with N2, and stir at 30°C for 12 h." Step (3) yields an epoxy-terminated bipyridine bis-quaternary ammonium salt compound, designated N4, with a yield of 88%, a quaternary ammonium salt conversion rate of 92%, and an epoxy conversion rate of 91%.

[0130] Example 5

[0131] The phrase in step (3), "Dissolve 15 mmol of the compound shown in formula 3 obtained in step (2) in 120 mL of N,N-dimethylformamide, add 30 mmol of sodium hydride in portions, protect with N2, and stir at 25°C for 12 h," is changed to "Dissolve 15 mmol of the compound shown in formula 3 obtained in step (2) in 120 mL of N,N-dimethylformamide, add 30 mmol of sodium hydride in portions, protect with N2, and stir at 15°C for 12 h." Step (3) yields an epoxy-terminated bipyridine bis-quaternary ammonium salt compound, designated N5, with a yield of 92%, a quaternary ammonium salt conversion rate of 93%, and an epoxy conversion rate of 85%.

[0132] Example 6

[0133] The phrase in step (3) "dissolve 15 mmol of the compound shown in formula 3 obtained in step (2) in 120 mL of N,N-dimethylformamide, add 30 mmol of sodium hydride in portions, protect with N2, and stir at 25°C for 12 h" is changed to "dissolve 15 mmol of the compound shown in formula 3 obtained in step (2) in 120 mL of N,N-dimethylformamide, add 30 mmol of sodium hydride in portions, protect with N2, and stir at 25°C for 16 h." Step (3) yields an epoxy-terminated bipyridine bis-quaternary ammonium salt compound numbered N6, with a yield of 91%, a quaternary ammonium salt conversion rate of 93%, and an epoxy conversion rate of 95%.

[0134] Example 7

[0135] The phrase in step (3), "Dissolve 15 mmol of the compound shown in Formula 3 obtained in step (2) in 120 mL of N,N-dimethylformamide, add 30 mmol of sodium hydride in portions, protect with N2, and stir at 25°C for 12 h," is changed to "Dissolve 15 mmol of the compound shown in Formula 3 obtained in step (2) in 120 mL of N,N-dimethylformamide, add 30 mmol of sodium hydride in portions, protect with N2, and stir at 25°C for 8 h." Step (3) yields an epoxy-terminated bipyridine bis-quaternary ammonium salt compound, designated N7, with a yield of 90%, a quaternary ammonium salt conversion rate of 92%, and an epoxy conversion rate of 91%.

[0136] Example 8

[0137] The phrase in step (1), "Dissolve 32 mmol of 4,4'-bipyridine in 50 mL of acetonitrile, then add 64 mmol of 3-bromo-1,2-bisphenol dropwise to the solution while stirring at 65 °C, and continuously stir the reaction mixture for 16 hours," is changed to "Dissolve 32 mmol of 4,4'-bipyridine in 50 mL of acetonitrile, then add 60.8 mmol of 3-bromo-1,2-bisphenol dropwise to the solution while stirring at 65 °C, and continuously stir the reaction mixture for 16 hours. Subsequently, the mixture is continuously stirred for 16 hours." Step (3) yields an epoxy-terminated bipyridine bisquaternary ammonium salt compound, designated N8, with a yield of 90%, a quaternary ammonium salt conversion rate of 90%, and an epoxy conversion rate of 92%. The molar ratio of 4,4'-bipyridine to 3-bromo-1,2-bisphenol is 1:1.9.

[0138] Example 9

[0139] The phrase in step (1), "Dissolve 32 mmol of 4,4'-bipyridine in 50 mL of acetonitrile, then add 64 mmol of 3-bromo-1,2-bisphenol dropwise to the solution while stirring at 65 °C, and continuously stir the reaction mixture for 16 hours," is changed to "Dissolve 32 mmol of 4,4'-bipyridine in 50 mL of acetonitrile, then add 67.2 mmol of 3-bromo-1,2-bisphenol dropwise to the solution while stirring at 65 °C, and continuously stir the reaction mixture for 16 hours. Subsequently, the mixture is continuously stirred for 16 hours." Step (3) yields an epoxy-terminated bipyridine bisquaternary ammonium salt compound, designated N9, with a yield of 91%, a quaternary ammonium salt conversion rate of 94%, and an epoxy conversion rate of 93%. The molar ratio of 4,4'-bipyridine to 3-bromo-1,2-bisphenol is 1:2.1.

[0140] Example 10

[0141] The phrase in step (1), "Dissolve 32 mmol of 4,4'-bipyridine in 50 mL of acetonitrile, then add 64 mmol of 3-bromo-1,2-bisphenol dropwise to the solution while stirring at 65 °C, and stir the reaction mixture continuously for 16 hours," is changed to "Dissolve 32 mmol of 4,4'-bipyridine in 50 mL of acetonitrile, then add 64 mmol of 3-bromo-1,2-bisphenol dropwise to the solution while stirring at 70 °C, and stir the reaction mixture continuously for 16 hours." Step (3) yields an epoxy-terminated bipyridine bisquaternary ammonium salt compound, designated N10, with a yield of 90%, a quaternary ammonium salt conversion rate of 94%, and an epoxy conversion rate of 92%.

[0142] Example 11

[0143] The phrase in step (2), "At 0°C, 25 mmol of the compound of formula 2 obtained in step (1) was dissolved in 100 mL of anhydrous dichloromethane, and 90 mmol of triethylamine was added. 50 mmol of p-toluenesulfonyl chloride was added to the solution, and the reaction mixture was stirred at room temperature for 12 h," was changed to "At 0°C, 25 mmol of the compound of formula 2 obtained in step (1) was dissolved in 100 mL of anhydrous dichloromethane, and 90 mmol of triethylamine was added. 75 mmol of p-toluenesulfonyl chloride was added to the solution, and the reaction mixture was stirred at room temperature for 12 h." Step (3) yielded an epoxy-terminated bipyridine bis-quaternary ammonium salt compound, designated N11, with a yield of 92%, a quaternary ammonium salt conversion rate of 92%, and an epoxy conversion rate of 92%. The molar ratio of the compound of formula 2 to p-toluenesulfonyl chloride was 1:3.

[0144] Example 12

[0145] The phrase in step (2), "At 0°C, 25 mmol of the compound of formula 2 obtained in step (1) was dissolved in 100 mL of anhydrous dichloromethane, and 90 mmol of triethylamine was added. 50 mmol of p-toluenesulfonyl chloride was added to the solution, and the reaction mixture was stirred at room temperature for 12 h," was changed to "At 0°C, 25 mmol of the compound of formula 2 obtained in step (1) was dissolved in 100 mL of anhydrous dichloromethane, and 90 mmol of triethylamine was added. 50 mmol of p-toluenesulfonyl chloride was added to the solution, and the reaction mixture was stirred at room temperature for 8 h." Step (3) yielded an epoxy-terminated bipyridine bisquaternary ammonium salt compound, designated N12, with a yield of 90%, a quaternary ammonium salt conversion rate of 93%, and an epoxy conversion rate of 90%.

[0146] Example 13

[0147] The phrase in step (2), "At 0°C, 25 mmol of the compound of formula 2 obtained in step (1) was dissolved in 100 mL of anhydrous dichloromethane, and 90 mmol of triethylamine was added. 50 mmol of p-toluenesulfonyl chloride was added to the solution, and the reaction mixture was stirred at room temperature for 12 h," was changed to "At 0°C, 25 mmol of the compound of formula 2 obtained in step (1) was dissolved in 100 mL of anhydrous dichloromethane, and 90 mmol of triethylamine was added. 50 mmol of p-toluenesulfonyl chloride was added to the solution, and the reaction mixture was stirred at room temperature for 16 h." Step (3) yielded an epoxy-terminated bipyridine bisquaternary ammonium salt compound, designated N13, with a yield of 90%, a quaternary ammonium salt conversion rate of 92%, and an epoxy conversion rate of 95%.

[0148] Example 14

[0149] In step (2), the phrase "at 0°C, 25 mmol of the compound shown in Formula 2 obtained in step (1) was dissolved in 100 mL of anhydrous dichloromethane, and 90 mmol of triethylamine was added" was changed to "at 0°C, 25 mmol of the compound shown in Formula 2 obtained in step (1) was dissolved in 100 mL of anhydrous dichloromethane, and 62.5 mmol of triethylamine was added." In step (3), the epoxy-terminated bipyridine bis-quaternary ammonium salt compound, designated N14, was obtained with a yield of 90%, a quaternary ammonium salt conversion rate of 93%, and an epoxy conversion rate of 93%.

[0150] Example 15

[0151] In step (2), the phrase "at 0°C, 25 mmol of the compound shown in formula 2 obtained in step (1) was dissolved in 100 mL of anhydrous dichloromethane, and 90 mmol of triethylamine was added" was changed to "at 0°C, 25 mmol of the compound shown in formula 2 obtained in step (1) was dissolved in 100 mL of dichloromethane, and 100 mmol of triethylamine was added." In step (3), the epoxy-terminated bipyridine bis-quaternary ammonium salt compound, designated N15, was obtained with a yield of 92%, a quaternary ammonium salt conversion rate of 92%, and an epoxy conversion rate of 94%.

[0152] Example 16

[0153] The phrase "dry the combined organic layers with Na2SO4, distill off the solvent under reduced pressure, and purify the crude product on silica gel with a mixture of ethyl acetate / petroleum ether at a volume ratio of 1:20" in step (3) is changed to "dry the combined organic layers with Na2SO4, distill off the solvent under reduced pressure, and purify the crude product on silica gel with a mixture of ethyl acetate / petroleum ether at a volume ratio of 1:10". Step (3) yields an epoxy-terminated bipyridine bisquaternary ammonium salt compound numbered N16, with a yield of 93%, a quaternary ammonium salt conversion rate of 93%, and an epoxy conversion rate of 93%.

[0154] Example 17 modifies step (1) by changing the statement: "32 mmol of 4,4'-bipyridine was dissolved in 50 mL of acetonitrile, and then 64 mmol of 3-bromo-1,2-bisphenol was added dropwise to the solution while stirring at 65 °C. The reaction mixture was stirred continuously for 16 hours. After the reaction was complete (monitored by TLC), it was cooled to room temperature. A large amount of solid precipitated out. The product was filtered and washed three times with 25 mL of ethyl acetate and 25 mL of diethyl ether, respectively. The solid was removed and dried under vacuum at 60 °C for 1 hour to obtain the compound shown in Formula 2, where R1 and R2 are methylene groups and X is Br. The molar ratio of 4,4'-bipyridine to 3-bromo-1,2-bisphenol is 1:2." to "32 mmol of 4,4'-bipyridine was dissolved in 50 mL of acetonitrile, and then 54.4 mmol of 3-bromo-1,2-bisphenol was added dropwise to the solution while stirring at 65 °C." 3-Bromo-1,2-bisphenol was added, and the reaction mixture was stirred continuously for 16 hours. After the reaction was complete (monitored by TLC), it was cooled to room temperature. A large amount of solid precipitated out, which was filtered and the product filter cake was washed three times with 25 mL of ethyl acetate and 25 mL of diethyl ether, respectively. The solid was removed and dried under vacuum at 60 °C for 1 hour to give the compound shown in Formula 2, wherein R1 and R2 are methylene groups and X is Br. The molar ratio of 4,4'-bipyridine to 3-bromo-1,2-bisphenol was 1:1.7. Step (3) yielded an epoxy-terminated bipyridine bisquaternary ammonium salt compound, designated N17, with a yield of 89%, a quaternary ammonium salt conversion of 89%, and an epoxy conversion of 92%.

[0155] Example 18 modifies step (2) by saying, “At 0°C, 25 mmol of the compound of formula 2 obtained in step (1) was dissolved in 100 mL of anhydrous dichloromethane, and 90 mmol of triethylamine was added. 50 mmol of p-toluenesulfonyl chloride was added to the solution, and the reaction mixture was stirred at room temperature for 12 h. The reaction mixture was diluted with 500 mL of water and extracted three times with anhydrous dichloromethane (100 mL each time). The combined organic extracts were washed with brine, dried with anhydrous Na2SO4, and concentrated under reduced pressure to obtain the compound of formula 3, wherein R1 and R2 are methylene, and X is Br. The molar ratio of the compound of formula 2 to p-toluenesulfonyl chloride is 1:2.” to “At 0°C, 25 mmol of the compound of formula 2 obtained in step (1) was dissolved in 100 mL of anhydrous dichloromethane, and 90 mmol of triethylamine was added. 50 mmol of p-toluenesulfonyl chloride was added to the solution, and the reaction mixture was stirred at room temperature for 12 h. The reaction mixture was diluted with 500 mL of water and extracted three times with anhydrous dichloromethane (100 mL each time). The combined organic extracts were washed with brine, dried with anhydrous Na2SO4, concentrated under reduced pressure to obtain the compound of formula 3, wherein R1 and R2 are methylene, and X is Br. The molar ratio of the compound of formula 2 to p-toluenesulfonyl chloride is 1:2.” The compound shown in Formula 2 was dissolved in 100 mL of anhydrous dichloromethane, and 90 mmol of triethylamine was added. 150 mmol of p-toluenesulfonyl chloride was added to the solution, and the reaction mixture was stirred at room temperature for 12 h. The reaction mixture was diluted with 500 mL of water and extracted three times (100 mL each time) with anhydrous dichloromethane. The combined organic extracts were washed with brine, dried over anhydrous Na2SO4, and concentrated under reduced pressure to give the compound shown in Formula 3, wherein R1 and R2 are methylene groups, and X is Br. The molar ratio of the compound shown in Formula 2 to p-toluenesulfonyl chloride was 1:6. Step (3) yielded an epoxy-terminated bipyridine bis-quaternary ammonium salt compound, designated N18, with a yield of 88%, a quaternary ammonium salt conversion of 89%, and an epoxy conversion of 94%.

[0156] Example 19

[0157] In step (2), the phrase "at 0°C, 25 mmol of the compound shown in formula 2 obtained in step (1) was dissolved in 100 mL of anhydrous dichloromethane, and 90 mmol of triethylamine was added" was changed to "at 0°C, 25 mmol of the compound shown in formula 2 obtained in step (1) was dissolved in 100 mL of anhydrous dichloromethane, and 150 mmol of triethylamine was added." In step (3), the epoxy-terminated bipyridine bis-quaternary ammonium salt compound, designated N19, was obtained with a yield of 87%, a quaternary ammonium salt conversion rate of 92%, and an epoxy conversion rate of 93%.

[0158] Example 20

[0159] The phrase "at 0°C, 15 mmol of the compound shown in Formula 3 obtained in step (2) was dissolved in 120 mL of N,N-dimethylformamide, and 30 mmol of sodium hydride was added in portions" in step (3) was changed to "at 0°C, 15 mmol of the compound shown in Formula 3 obtained in step (2) was dissolved in 120 mL of N,N-dimethylformamide, and 75 mmol of sodium hydride was added in portions". Step (3) yielded an epoxy-terminated bipyridine bisquaternary ammonium salt compound numbered N20, with a yield of 88%, a quaternary ammonium salt conversion rate of 90%, and an epoxy conversion rate of 95%.

[0160] Comparative Example 1

[0161] Sodium hydride is not added in step (3). Step (3) yields an epoxy-terminated bipyridine bis-quaternary ammonium salt compound, designated D1, with a yield of 67%, a quaternary ammonium salt conversion of 93%, and an epoxy conversion of 12%.

[0162] In Comparative Example 2, triethylamine was not added in step (2). Step (3) yielded an epoxy-terminated bipyridine bisquaternary ammonium salt compound, designated D2, with a yield of 60%, a quaternary ammonium salt conversion of 75%, and an epoxy conversion of 26%.

[0163] In Comparative Example 3, the phrase "dissolve 32 mmol of 4,4'-bipyridine in 50 mL of acetonitrile, then add 64 mmol of 3-bromo-1,2-diol dropwise to the solution while stirring at 65 °C, and stir the reaction mixture continuously for 16 hours" in step (1) was changed to "dissolve 32 mmol of 4,4'-bipyridine in 50 mL of acetonitrile, then add 64 mmol of 2-bromoethanol dropwise to the solution while stirring at 65 °C, and stir the reaction mixture continuously for 16 hours." Step (3) yielded an epoxy-terminated bipyridine bisquaternary ammonium salt compound, designated D3, with a yield of 58%, a quaternary ammonium salt conversion rate of 52%, and an epoxy conversion rate of 0%.

[0164] The results from Examples 1, 8-9, 17, and Comparative Example 3 show that within a certain range, the synthesis yield, quaternary ammonium salt conversion, and epoxide conversion of 3-bromo-1,2-diol are all relatively ideal. Comparative Example 3 used the monohydroxy bromide 2-bromoethanol, which could not generate epoxide functional groups in subsequent reactions. The results from Examples 1, 19, and Comparative Example 2 show that triethylamine can significantly improve the epoxide conversion of the product. The results from Examples 1, 2, 3, 20, and Comparative Example 1 show that sodium hydride can significantly improve the epoxide conversion of the product.

[0165] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. An epoxy-terminated bipyridine bis-quaternary ammonium salt compound, characterized in that, The compound has the structure shown in Formula I: Wherein, R1 and R2 are each independently C1-C3 alkylene groups; X is F, Cl or Br.

2. The epoxy-terminated bipyridine bis-quaternary ammonium salt compound according to claim 1, wherein, R1 and R2 are methylene groups; And / or, X is Cl or Br.

3. A method for preparing the epoxy-terminated bipyridine bis-quaternary ammonium salt compound according to claim 1 or 2, characterized in that, The method includes: (1) After mixing 4,4'-bipyridine, at least one compound of Formula 1 and a first organic solvent, a first reaction is carried out, and after solid-liquid separation and drying, the compound of Formula 2 is obtained. (2) In the presence of the first catalyst and the second organic solvent, the compound shown in Formula 2 is mixed with the sulfonyl chloride compound in the second reaction, and after the first extraction and drying, the compound shown in Formula 3 is obtained. (3) In the presence of a third organic solvent, the compound shown in Formula 3 is mixed with the second catalyst in a third reaction, and after quenching, second extraction, drying and purification, the quaternary ammonium salt shown in Formula I is obtained. In this context, R, R1, and R2 are each independently C1-C3 alkylene groups; X is F, Cl, or Br; and R3, R4, R5, R6, and R7 are each independently H, methyl, tert-butyl, or dodecyl.

4. The method according to claim 3, wherein, The molar ratio of 4,4'-bipyridine to the compound shown in Formula 1 is 1:1.8-2.2, preferably 1:1.9-2.

1.

5. The method according to claim 3 or 4, wherein, The first catalyst is selected from at least one of triethylamine, N,N-dimethylcyclohexylamine, diethylamine, and triphenylamine, preferably triethylamine; Preferably, the molar ratio of the first catalyst to the compound shown in Formula 2 is 1-5:1, more preferably 2-4:

1.

6. The method according to any one of claims 3-5, wherein, The sulfonyl chloride compound is selected from at least one of benzenesulfonyl chloride, p-toluenesulfonyl chloride, 3-tert-butylbenzenesulfonyl chloride, 2,5-dimethylbenzenesulfonyl chloride and p-dodecylbenzenesulfonyl chloride, preferably p-toluenesulfonyl chloride; Preferably, the molar ratio of the compound shown in Formula 2 to the sulfonyl chloride compound is 1:1.5-5, more preferably 1:1.8-4.

7. The method according to any one of claims 3-6, wherein, The second catalyst is selected from at least one of sodium hydride, cesium carbonate, and sodium carbonate, preferably sodium hydride; Preferably, the molar ratio of the compound shown in Formula 3 to the second catalyst is 1:1-4, more preferably 1:2-3.

8. The method according to any one of claims 3-7, wherein, The mixing temperature of the first mixture is 50-75°C, preferably 60-70°C; And / or, the second mixing and the third mixing are each carried out independently under ice bath conditions; Preferably, the mixing times for the second and third mixing are each 10-60 min independently.

9. The method according to any one of claims 3-8, wherein, The conditions for the first reaction include: a reaction temperature of 50℃-75℃ and a reaction time of 6-36h, preferably, a reaction temperature of 60-70℃ and a reaction time of 12-24h; And / or, the conditions for the second reaction include: a reaction temperature of 5-40°C and a reaction time of 6-24 h, preferably, a reaction temperature of 15-30°C and a reaction time of 8-16 h; And / or, the conditions for the third reaction include: a reaction temperature of 5-40°C and a reaction time of 6-20 h, preferably, a reaction temperature of 15-30°C and a reaction time of 8-16 h.

10. The method according to any one of claims 3-9, wherein, The first organic solvent, the second organic solvent, and the third organic solvent are each independently selected from at least one of acetonitrile, dichloromethane, N,N-dimethylformamide, and N,N-dimethylacetamide; Preferably, the first organic solvent, the second organic solvent, and the third organic solvent are different.

11. The method according to any one of claims 3-10, wherein, The purification was performed in a chromatography column; Preferably, the eluent for purification is a mixture of ethyl acetate and petroleum ether, wherein the volume ratio of ethyl acetate to petroleum ether is 0.05-0.25:

1.

12. The use of an epoxy-terminated bipyridine quaternary ammonium salt compound as described in claim 1 or 2 in the preparation of a separation membrane or a precursor for a functional material.

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