WO2020238731A1

WO2020238731A1 - Bicyclic ammonium ion polybenzimidazole, anion exchange membrane, preparation method therefor and use thereof

Info

Publication number: WO2020238731A1
Application number: PCT/CN2020/091452
Authority: WO
Inventors: 朱秀玲; 刘品阳
Original assignee: 大连理工大学
Priority date: 2019-05-28
Filing date: 2020-05-21
Publication date: 2020-12-03
Also published as: CN110527088B; CN110527088A

Abstract

Disclosed are a bicyclic ammonium ion polybenzimidazole, an anion exchange membrane, and a preparation method therefor and the use thereof, which belong to the technical field of polyelectrolytes and ion exchange membranes. The method involves firstly synthesizing a halogenated spiro ammonium salt, then introducing halogenated spiro ammonium into the molecular chain of polybenzimidazole by means of a grafting reaction, so as to synthesize bicyclic ammonium ion polybenzimidazole, which is subjected to basic ion exchange to prepare a bicyclic ammonium ion polybenzimidazole anion exchange membrane. The bicyclic ammonium ion polybenzimidazole anion exchange membrane prepared according to the method has a good polymer film formation property, a high ionic conductivity, significantly improved mechanical properties and alkali resistance stability, and a good dimensional stability, and can be widely used in fields related to ion exchange membranes, such as fuel cells, flow cells, water electrolysis and electrodialysis, seawater desalination, etc.

Description

Bicyclic ammonium ion polybenzimidazole and anion exchange membrane as well as preparation method and application thereof

Technical field

The invention belongs to the technical field of polymer electrolytes and ion exchange membranes, and relates to a bicyclic ammonium ion polybenzimidazole and anion exchange membrane, and a preparation method and application thereof.

Background technique

In recent years, the energy crisis and resource depletion have triggered an urgent need for clean energy in various industries and people's livelihoods. Countries around the world have paid more attention to the development of clean energy. Fuel cells have attracted more and more attention of scientific researchers due to their green environmental protection and high energy conversion rate. At the same time, fuel cells have also made a series of considerable progress. Alkaline anion exchange membrane fuel cell, as a kind of fuel cell, has the advantages of not requiring precious metals as catalysts and simple water management. At the same time, it also faces the challenges of low ion conductivity and poor alkali resistance stability. This is also the focus of the present invention. The place.

As an excellent special engineering plastic, polybenzimidazole exhibits excellent mechanical stability, heat resistance and alkali resistance. It has attracted the attention of more and more researchers. It is used in ionic membranes for fuel cells and energy storage batteries. Applications in other fields have attracted attention. Currently, polybenzimidazole is mostly used for high-temperature proton membranes. The patent [Wang Lei et al., Patent Publication No.: CN 106684415 A] discloses the preparation of a PBI-doped phosphoric acid high-temperature proton membrane. The patent [Lu Jinbo, etc., Patent Publication No. : CN 107887626 A] discloses a cross-linked composite high-temperature proton membrane and its preparation method. The patent [Yan Xiaoming et al., Patent Publication No.: CN 107674417 A] discloses a non-ionic hydrophilic side chain polybenzo Imidazole and its preparation method. However, there are few published documents about using polybenzimidazole for basic anion exchange membranes. The patent [Zhu Xiuling et al., Patent Publication No.: CN 108623806 A] discloses a polybenzimidazole with pendant amino groups and its anion exchange membrane And preparation method.

Summary of the invention

Aiming at the problems of low ion conductivity and poor alkali resistance stability in the current basic anion resin and its ion exchange membrane, the present invention provides a bicyclic ammonium with good mechanical properties, high alkali resistance and good dimensional stability. Ionic polybenzimidazole and its anion exchange membrane and preparation method thereof.

The present invention is realized by adopting the following technical solutions:

A bicyclic ammonium ion polybenzimidazole, which is characterized in that it has the following structure:

Among them, n=0～0.8;

Z is Cl ^{^-,} Br ^-, or OH ^- ions, preferably OH ^- ions;

A is a single bond, methylene -CH ₂ -, ether bond -O- or carbonyl -CO-, preferably A is a single bond or methylene -CH ₂ -;

X is the aliphatic structure:

Among them, 2≤n'≤18; preferably X is 2≤n'≤12;

Y has the following structure:

Preferably Y is (a), (c), (e) and (f);

G is a spirocyclic ammonium ion, the structure is as follows:

The preferred structure of G is (Gb), (Gd).

An integer of 0≤y≤12, preferably an integer of 2≤y≤6; an integer of 0<q≤12, preferably an integer of 2≤q≤6;

A preparation method of bicyclic ammonium ion polybenzimidazole anion exchange membrane, characterized by comprising the following steps:

Step 1. Synthesis of polybenzimidazole

The polybenzimidazole is synthesized from tetraamine monomer (II) and diacid monomer (III) through solution polycondensation.

The structure of the tetraamine monomer (II) is as follows:

Among them, A is a single bond, methylene -CH ₂ -, ether bond -O- or carbonyl -CO-, preferably A is a single bond or methylene -CH ₂ -;

The structure of the diacid monomer (III) is as follows:

HOOC-X-COOH and HOOC-Y-COOH

Among them, X is an aliphatic structure:

Wherein 2≤n'≤18, preferably X is 2≤n'≤12;

Y has the following structure:

Preferably Y is (a), (c), (e) and (f);

Add polyphosphoric acid into a stirred reactor. Under the protection of N ₂ , add tetraamine monomer (Ⅱ) and diacid monomer (Ⅲ) HOOC-X-COOH and HOOC-Y-COOH in equal molar ratio. Stir and dissolve so that the total concentration of monomers II and III is 1-20wt%. The temperature is raised to 90-140°C and the reaction is stirred for 0.5-10h, the temperature is raised to 140-160°C and the reaction is stirred for 0.5-10h, and the temperature is raised to 160-190°C for 8-30h. After the polymerization reaction is over, the product is poured into a large amount of deionized water, an excess of NaHCO _{3 is} added, and the mixture is stirred overnight. Filter and wash the polymer with deionized water until neutral. The product is dried to obtain polybenzimidazole.

Step 2-1, Synthesis of halogenated spirocyclic ammonium salt (Ⅳ)

A certain amount of piperazine or methyl-piperazine is added to the solvent 1 of dibromopentane, the basic compound 2 is added, and the temperature is raised to 30-90° C. and the reaction is stirred for 6-72 hours. After the reaction is over, filter to obtain N.

Add a certain amount of N synthesized above to a certain amount of dihaloalkane P-(CH ₂ ) _w -P (P is Cl or Br atom, 0<w≤12 integer, preferably 2≤w≤8) in solvent 1 In the process, the basic compound 2 is added and reacted at 30-90°C for 4-100 hours. After the reaction is completed, it is filtered and the product is centrifuged and dried to obtain IV.

Step 2-2, Synthesis of halogenated spirocyclic ammonium salt (Ⅴ)

Add a certain amount of 1,ω-dipiperidine alkane (M) to a certain amount of dihaloalkane P-(CH ₂ ) _m -P (P is Cl or Br atom) in solvent 1, add basic compound 2 in React at 30～90℃ for 4～100h. After the reaction, filter and dry to obtain M'; add a certain amount of M'to a certain amount of P-(CH ₂ ) _m -P (P is Cl or Br atom, 0＜m≤ Integer of 12, preferably 2≤m≤8) In the solvent 2 solution, react at 30-90°C for 6-100h. After the reaction, the solvent will be evaporated, filtered and dried to obtain V.

Step 3. Synthesis of bicyclic ammonium ion polybenzimidazole (Ⅰ)

A certain amount of synthesized polybenzimidazole is heated and dissolved in solvent 2 to obtain a 0.5-10wt% solution. Add halogenated spirocyclic ammonium salt (IV) or halogenated spirocyclic ammonium salt (V), and react at 30～150℃. 8 ~100h. After the reaction is complete, pour into precipitant 1, filter, wash the filter cake with deionized water three times, and dry the product to obtain I. Dissolve I in solvent 1 to prepare a 0.5-15% solution to obtain bicyclic ammonium ion polybenzimidazole.

Further, in the above technical solution, the solvent 2 is toluene, dichloromethane, tetrahydrofuran, methanol, ethanol, N,N-dimethylacetamide, dimethylsulfoxide, N,N-dimethylformaldehyde One or a mixture of amides and N-methylpyrrolidone;

The solvent 3 is one of dichloromethane, acetone, methanol, ethanol, N,N-dimethylacetamide, dimethylsulfoxide, N,N-dimethylformamide, and N-methylpyrrolidone Or a mixture of several.

Further, in the above technical scheme, in step 2-1, the molar ratio of piperazine or methyl-piperazine to dibromopentane is 0.05-1:1, and the piperazine or methyl-piperazine and the basic compound The molar ratio of 2 is 0.1 to 1:1, preferably 0.2 to 1:1; the molar ratio of N to dihaloalkane P-(CH ₂ ) _w -P is 0.05 to 1:1, preferably 0.1 to 0.5:1;

In step 2-2, the molar ratio of 1,ω-dipiperidine alkane (M) to dihaloalkane P-(CH ₂ ) ₅ -P is 1:1 to 0.1, preferably 1:0.5 to 1, M'and The molar ratio of P-(CH ₂ ) _m -P is 0.05-1:1, preferably 0.1-0.5:1; the molar ratio of 1,ω-dipiperidine alkane (M) to the basic compound 2 is 0.1-1 :1, preferably 0.2 to 1:1.

In step 3, the molar ratio of polybenzimidazole to IV is 0.1-2:1, preferably 0.2-1:1.

Further, in the above technical solution, the precipitation agent 1 is one or a mixture of methanol, ethanol, ether, ethyl acetate, dichloromethane, tetrahydrofuran, acetone, and water.

Further, in the above technical solution, the basic compound 2 can be one or more of sodium bicarbonate, potassium bicarbonate, sodium carbonate, potassium carbonate, cesium carbonate, sodium hydride, and lithium hydride.

Further, in the above technical solution, the viscosity average molecular weight of the polybenzimidazole is 10,000-450,000 g/mol, and the degree of polymerization n is 20-1200.

The present invention provides a method for preparing bicyclic ammonium ion polybenzimidazole anion exchange membrane. The above bicyclic ammonium ion polybenzimidazole I is dissolved in solvent 1 to prepare a 1-15wt% solution, filtered, and the filtrate is cast on a clean plate Lay the film and transfer to the oven to dry. Put the prepared membrane in a 1M NaOH or 1M KOH aqueous solution for 24 to 48 hours, take it out and soak in water for 24 hours, take it out and dry it to obtain a bicyclic ammonium ion polybenzimidazole anion exchange membrane.

Further, in the above technical scheme, the solvent 1 is selected from toluene, methanol, ethanol, dichloromethane, tetrahydrofuran, acetonitrile, acetone, ethyl acetate, N,N-dimethylacetamide, dimethylsulfoxide, One or a mixture of N,N-dimethylformamide and N-methylpyrrolidone.

The present invention provides the application of the bicyclic ammonium ion polybenzimidazole as an electrolyte in the fields of fuel cells, flow batteries, water electrolysis, electrodialysis, and membrane separation.

Another object of the present invention is to provide the application of the bicyclic ammonium ion polybenzimidazole anion exchange membrane obtained by the above preparation method in related fields such as fuel cells, flow batteries, water electrolysis and electrodialysis, seawater desalination and membrane separation.

Compared with the prior art, the present invention has the following advantages: the bicyclic ammonium ion polybenzimidazole and its anion exchange membrane prepared according to the present invention have good film forming properties, high ion conductivity, membrane toughness and alkali resistance stability. It is widely used in fuel cells, flow batteries, electrolysis and electrodialysis, and plasma membranes related to seawater desalination.

Description of the drawings

Figure 1 is a hydrogen nuclear magnetic spectrum of piperazine spirocyclic ammonium bromide prepared in Example 4;

2 is a hydrogen nuclear magnetic spectrum of the methylpiperazine spiro ring grafted PBI anion exchange membrane prepared in Example 4;

3 is a hydrogen nuclear magnetic spectrum of the PBI anion exchange membrane grafted with dipiperidine spirocyclic ammonium prepared in Example 7. FIG.

Detailed ways

The following examples further illustrate in detail a bicyclic ammonium ion polybenzimidazole anion exchange membrane of the present invention and its preparation method and application, but it is not used to limit the scope of protection of the present invention. Unless otherwise specified, the chemical reagents and The medicines are all commercially available. Unless otherwise specified, the methods involved are conventional methods.

Test methods involved in the embodiment:

Ion exchange capacity (IEC) test method: Take 3 parts of monoammonium ion polybenzimidazole 0.1g, soak them in 100ml, 1M NaOH for 24h, and then soak in 100ml deionized water for 24h and wash with water until neutral, vacuum Dry in an oven at 60 degrees, and soak them in 0.02002M HCl for 24 hours. Add a few drops of phenolphthalein and titrate with 0.0182M NaOH to turn pink. Record the amount of NaOH needed. Subtract the moles of NaOH from the moles of HCl and divide by 0.1 (g) to get the IEC.

Test equipment involved in the embodiment:

Conductivity test: The electrochemical workstation used is produced by Shanghai Chenhua Instrument Co., Ltd., model: chi660c.

NMR test: The NMR spectrometer used is produced by Varian Company, the model is BrukerAvance II 400. In the NMR spectrum, D ₂ O was used as the solvent for both salts and DMSO-d6 was used as the solvent for the polymer after grafting.

Table 1 is the chemical structure of the bicyclic ammonium ion polybenzimidazole used in the examples.

Table 1

Example 1

Add polyphosphoric acid to the reactor with stirring, and under the protection of N ₂ , add biphenyltetraamine, succinic acid and biphenyl diphthalic acid (the total number of moles of succinic acid and biphenyl diphthalic acid is equal to benztetramine The number of moles), heating and stirring to dissolve, so that the total mass concentration of the monomer is 10wt%. The temperature was raised to 110°C and stirred for 1 hour, 130°C was reacted for 1 hour, and then the temperature was raised to 170°C for 8 hours, until the viscosity of the system no longer increased. After the polymerization is over, the product is poured into a large amount of deionized water, and excess NaHCO _{3 is} added, and the mixture is stirred overnight. Filter and wash the polymer with deionized water until neutral. The product is dried to obtain polybenzimidazole.

Add methylpiperazine and dibromopentane in an equimolar ratio to acetone, and heat to 30°C and stir for 15h. After the reaction is over, filter to obtain product N. Add 10 mol of the above product N to 100 mol of dibromohexane and dichloroethane, and react at 30° C. for 12 h. After the reaction is completed, it is filtered, and the product is centrifuged and dried to obtain product IV.

10 mol of the synthesized polybenzimidazole was heated and dissolved in N-methylpyrrolidone (NMP) to obtain a 7wt% solution, and 10 mol of the above product IV was added and reacted at 40°C for 15 hours. After the reaction is completed, ethanol is poured into, filtered, the filter cake is washed with deionized water three times, and the product is dried to obtain diammonium ion PBI.

The synthesized diammonium ion PBI was dissolved in NMP to prepare a 5 wt% solution, vacuumed for 0.5 h, filtered, and the filtrate was cast on a clean flat plate to spread a film, and then transferred to an oven at 60°C for drying. The prepared membrane was immersed in a 1M NaOH solution for 24 hours, taken out and soaked in water for 24 hours, taken out and dried to obtain a diammonium ion PBI anion membrane.

After testing, the OH ^- conductivity of the diammonium PBI anion membrane at 80°C is 53mS/cm, and the ionic membrane has good toughness. After immersing in a 1M KOH solution at 80°C for 1300h, the OH ^- ion conductivity remains 85%.

Example 2

Add polyphosphoric acid to the reactor with stirring, and under the protection of N ₂ , add biphenyltetraamine, succinic acid and biphenyl diphthalic acid (the total number of moles of succinic acid and biphenyl diphthalic acid is equal to benztetramine Mol), heating and stirring to dissolve, so that the total mass concentration of the monomer is 15wt%. The temperature was raised to 100°C and stirred for 5 hours, 140°C was reacted for 0.5 hours, and then the temperature was raised to 170°C for 8 hours, until the viscosity of the system no longer increased. After the polymerization is over, the product is poured into a large amount of deionized water, and excess NaHCO _{3 is} added, and the mixture is stirred overnight. Filter and wash the polymer with deionized water until neutral. The product is dried to obtain polybenzimidazole.

The equimolar ratio of methylpiperazine and dibromopentane were added to acetone, and the temperature was raised to 50° C. and the reaction was stirred for 12 hours. After the reaction is over, filter to obtain product N. 10 mol of the above product N was added to 120 mol of dibromohexane and dichloroethane, and reacted at 50° C. for 20 h. After the reaction is completed, it is filtered, and the product is centrifuged and dried to obtain product IV.

10mol of the synthesized polybenzimidazole was heated and dissolved in N-methylpyrrolidone (NMP) to obtain a 7wt% solution, 12mol of the above product IV was added, and the reaction was carried out at 40°C for 15h. After the reaction is completed, ethanol is poured into, filtered, the filter cake is washed with deionized water three times, and the product is dried to obtain diammonium ion PBI.

Dissolve the synthesized diammonium ion PBI in N,N-dimethylacetamide (DMAc) to prepare a 7wt% solution, vacuum for 0.5h, filter, cast the filtrate on a clean plate, and transfer it to a 60℃ oven dry. The prepared membrane was immersed in a 1M NaOH solution for 24 hours, taken out and soaked in water for 24 hours, taken out and dried to obtain a diammonium ion PBI anion membrane.

After testing, the OH ^- conductivity of the diammonium ion PBI anion membrane at 80°C is 45mS/cm, and the ionic membrane has good toughness. After being immersed in a 1M KOH solution at 80°C for 1200h, the OH ^- ion conductivity remains 85%.

Example 3

Add polyphosphoric acid in a stirred reactor, under the protection of N ₂ , add benzhydryl tetraamine, oxalic acid and isophthalic acid (the total moles of oxalic acid and isophthalic acid are equal to diphenyl The number of moles of methyl tetraamine) is heated and stirred to dissolve so that the total mass concentration of the monomer is 10 wt%. The temperature was raised to 130°C and stirred for 2 hours, 150°C for 4 hours, and then heated to 190°C for 6 hours, until the viscosity of the system no longer increased. After the polymerization is over, the product is poured into a large amount of deionized water, and excess NaHCO _{3 is} added, and the mixture is stirred overnight. Filter and wash the polymer with deionized water until neutral. The product is dried to obtain polybenzimidazole.

The equimolar ratio of 1,6-dipiperidine hexane and dibromopentane were added to acetone, and the reaction was stirred at 40°C for 24 hours. After the reaction is completed, filter and dry to obtain product M'; add 10 mol of the above product M'to 20 mol of dibromobutane in acetonitrile solution, and react at 50°C for 10 hours. After the reaction, the solvent was spun off, filtered and dried to obtain product IV.

10 mol of the synthesized polybenzimidazole is heated and dissolved in NMP to obtain an 8 wt% solution, 20 mol of the above product IV is added, and the reaction is carried out at 50° C. for 24 hours. After the reaction is over, acetone is poured into, filtered, the filter cake is washed with deionized water three times, and the product is dried to obtain diammonium ion PBI.

Dissolve the synthesized diammonium ion PBI in N,N-dimethylformamide (DMF) to prepare a 1wt% solution, vacuum for 0.5h, filter, cast the filtrate on a clean plate, and transfer it to a 60℃ oven dry. The prepared membrane was immersed in a 1M NaOH solution for 24 hours, taken out and soaked in water for 24 hours, taken out and dried to obtain a diammonium ion PBI anion membrane.

After testing, the OH ^- conductivity of the bisammonium PBI anion membrane at 80°C is 46mS/cm, and the ionic membrane has good toughness. After being immersed in a 1M KOH solution at 80°C for 1100h, the OH ^- ion conductivity remains 84%.

Example 4

Add polyphosphoric acid into a stirred reactor, and under the protection of N ₂ , add benztetramine, oxalic acid and diphenyl ether diacid (the total number of moles of oxalic acid and diphenyl ether diacid is equal to biphenyl). The number of moles of tetraamine) is heated and stirred to dissolve so that the total mass concentration of the monomer is 10% by weight. The temperature was raised to 120°C and stirred for 3h, 145°C was reacted for 2h, and then the temperature was raised to 180°C for 25h, until the viscosity of the system no longer increased. After the polymerization is over, the product is poured into a large amount of deionized water, and excess NaHCO _{3 is} added, and the mixture is stirred overnight. Filter and wash the polymer with deionized water until neutral. The product is dried to obtain polybenzimidazole.

10mol methylpiperazine and 80mol dibromopentane were added to acetone, and the temperature was raised to 60°C and the reaction was stirred for 15h. After the reaction is over, filter to obtain product N. 10 mol of the above product N was added to 30 mol of dibromohexane and dichloroethane, and reacted at 50° C. for 12 hours. After the reaction is completed, it is filtered, and the product is centrifuged and dried to obtain product IV.

10 mol of the synthesized polybenzimidazole was heated and dissolved in N-methylpyrrolidone (NMP) to obtain a 7wt% solution, and 10 mol of the above product IV was added and reacted at 70°C for 15 hours. After the reaction is completed, ethanol is poured into, filtered, the filter cake is washed with deionized water three times, and the product is dried to obtain diammonium ion PBI.

The synthesized diammonium ion PBI was dissolved in DMSO to prepare a 10wt% solution, vacuumed for 0.5h, filtered, and the filtrate was cast on a clean flat plate and then transferred to an oven at 60°C for drying. The prepared membrane was immersed in a 1M NaOH solution for 24 hours, taken out and soaked in water for 24 hours, taken out and dried to obtain a diammonium ion PBI anion membrane.

After testing, the OH ^- conductivity of the diammonium ion PBI anion membrane at 80°C is 50mS/cm, and the ion membrane has good toughness. After immersing in a 1M KOH solution at 80°C for 1400h, the OH ^- ion conductivity remains 84%.

Example 5 was added polyphosphoric acid in a stirred reactor under N ₂ protection, was added an equimolar amount of the amine and diphenylmethane biphenyltetracarboxylic acid, heated and stirred to dissolve, so that the total monomer concentration was 5wt%. The temperature was raised to 110°C and stirred for 8 hours, 160°C for 5 hours, and then heated to 175°C for 15 hours, until the viscosity of the system no longer increased. After the polymerization is over, the product is poured into a large amount of deionized water, and excess NaHCO _{3 is} added, and the mixture is stirred overnight. Filter and wash the polymer with deionized water until neutral. The product is dried to obtain polybenzimidazole.

10mol of 1,4-dipiperidinebutane and 12mol of dibromopentane were added to acetone, and the reaction was stirred at 40°C for 10h. After the reaction is completed, it is filtered and dried to obtain the product M'; 10 mol of the above product M'is added to 20 mol of dibromobutane in acetone solution, and reacted at 90°C for 8 hours. After the reaction, the solvent was spun off, filtered and dried to obtain product IV.

10 mol of the synthesized polybenzimidazole was heated and dissolved in NMP to obtain a 5 wt% solution, 10 mol of the above product IV was added, and the reaction was carried out at 80° C. for 8 hours. After the reaction is over, acetone is poured into, filtered, the filter cake is washed with deionized water three times, and the product is dried to obtain diammonium ion PBI.

The synthesized diammonium ion PBI was dissolved in DMAc to prepare a 6 wt% solution, vacuumed for 0.5 h, filtered, and the filtrate was cast on a clean flat plate and then transferred to an oven at 60°C for drying. The prepared membrane was immersed in a 1M NaOH solution for 24 hours, taken out and soaked in water for 24 hours, taken out and dried to obtain a diammonium ion PBI anion membrane.

After testing, the OH ^- conductivity of the diammonium ion PBI anion membrane at 80°C is 45mS/cm, and the ionic membrane has good toughness. After immersing in a 1M KOH solution at 80°C for 1200h, the OH ^- ion conductivity remains 80%.

Example 6

Add polyphosphoric acid into a stirred reactor, and under the protection of N ₂ , add biphenyltetraamine, pimelic acid and diphenyl ether diacid (the total number of moles of pimelic acid and diphenyl ether diacid is equal to biphenyl). The number of moles of tetraamine) is heated and stirred to dissolve so that the total mass concentration of the monomer is 10% by weight. The temperature was raised to 140°C and stirred for 1 hour, 160°C for 1 hour, and then heated to 185°C for 12 hours, until the viscosity of the system no longer increased. After the polymerization is over, the product is poured into a large amount of deionized water, and excess NaHCO _{3 is} added, and the mixture is stirred overnight. Filter and wash the polymer with deionized water until neutral. The product is dried to obtain polybenzimidazole.

10mol methylpiperazine and 30mol dibromopentane were added to acetone, and the temperature was raised to 70°C and the reaction was stirred for 12h. After the reaction is over, filter to obtain product N. Add 10 mol of the above product N to 50 mol of dibromohexane in tetrahydrofuran, and react at 70° C. for 15 hours. After the reaction is completed, it is filtered, and the product is centrifuged and dried to obtain IV.

10 mol of the synthesized polybenzimidazole was heated and dissolved in NMP to obtain a 7 wt% solution, 20 mol of the above product IV was added, and the reaction was carried out at 90° C. for 16 hours. After the reaction is completed, ethanol is poured into, filtered, the filter cake is washed with deionized water three times, and the product is dried to obtain diammonium ion PBI.

The synthesized diammonium ion PBI was dissolved in DMSO to prepare a 5 wt% solution, vacuumed for 0.5 h, filtered, and the filtrate was cast on a clean flat plate to spread a film, and then transferred to an oven at 60°C for drying. The prepared membrane was immersed in a 1M NaOH solution for 24 hours, taken out and soaked in water for 24 hours, taken out and dried to obtain a diammonium ion PBI anion membrane.

After testing, the OH ^- conductivity of the bisammonium PBI anion membrane at 80°C is 50mS/cm, and the ionic membrane has good toughness. After immersing in a 1M KOH solution at 80°C for 1200h, the OH ^- ion conductivity remains 81%.

Example 7

Add polyphosphoric acid into a stirred reactor, and under the protection of N ₂ , add biphenyltetraamine, adipic acid and diphenyl ether diacid (the total number of moles of adipic acid and diphenyl ether diacid is equal to biphenyl tetrakis The number of moles of amine) is heated and stirred to dissolve, so that the total mass concentration of the monomer is 8 wt%. The temperature was raised to 130°C and stirred for 8 hours, at 150°C for 3 hours, and then heated to 170°C for 14 hours, until the viscosity of the system no longer increased. After the polymerization is over, the product is poured into a large amount of deionized water, and excess NaHCO _{3 is} added, and the mixture is stirred overnight. Filter and wash the polymer with deionized water until neutral. The product is dried to obtain polybenzimidazole.

10 mol of 1,2-dipiperidine ethane and 80 mol of dibromopentane were added to acetone, and the reaction was stirred at 55° C. for 8 hours. After the reaction is completed, it is filtered and dried to obtain product M'; 10 mol of the above product M'is added to 30 mol of dibromohexane in dichloroethane solution, and reacted at 55°C for 16 hours. After the reaction, the solvent was spun off, filtered and dried to obtain product IV.

10 mol of the synthesized polybenzimidazole is heated and dissolved in NMP to obtain an 8 wt% solution, 10 mol of the above product IV is added, and the reaction is carried out at 100° C. for 12 hours. After the reaction is over, acetone is poured into, filtered, the filter cake is washed with deionized water three times, and the product is dried to obtain diammonium ion PBI.

The synthesized diammonium ion PBI was dissolved in DMAc to prepare a 5wt% solution, vacuumed for 0.5h, filtered, and the filtrate was cast on a clean flat plate to spread a film, and then transferred to an oven at 60°C for drying. The prepared membrane was immersed in a 1M NaOH solution for 24 hours, taken out and soaked in water for 24 hours, taken out and dried to obtain a diammonium ion PBI anion membrane.

After testing, the OH ^- conductivity of the diammonium ion PBI anion membrane at 80°C is 65mS/cm, and the ionic membrane has good toughness. After being immersed in a 1M KOH solution at 80°C for 1500h, the OH ^- ion conductivity remains 80%.

Example 8

Add polyphosphoric acid in a stirred reactor, and under the protection of N ₂ , add benzhydryltetraamine and diphenylmethanedioic acid (the total moles of diphenylmethanedioic acid are equal to the moles of benzhydryltetraamine Number), heating and stirring to dissolve, so that the total mass concentration of the monomer is 8wt%. The temperature was raised to 130°C and stirred for 2 hours, 150°C for 4 hours, and then heated to 190°C for 6 hours, until the viscosity of the system no longer increased. After the polymerization is over, the product is poured into a large amount of deionized water, and excess NaHCO _{3 is} added, and the mixture is stirred overnight. Filter and wash the polymer with deionized water until neutral. The product is dried to obtain polybenzimidazole.

10 mol of 1,2-dipiperidine ethane and 10 mol of dibromopentane were added to acetone, and the reaction was stirred at 50° C. for 12 h. After the reaction is completed, it is filtered and dried to obtain product M'; 10 mol of the above product M'is added to 30 mol of dibromobutane in acetone solution, and reacted at 40°C for 12 hours. After the reaction, the solvent was spun off, filtered and dried to obtain product IV.

10 mol of the synthesized polybenzimidazole was heated and dissolved in NMP to obtain a 2 wt% solution, and 10 mol of the above product IV was added and reacted at 50° C. for 30 hours. After the reaction is over, acetone is poured into it, filtered, the filter cake is washed with deionized water 3 times, the product is dried, and the diammonium ion PBI is obtained.

The synthesized diammonium ion PBI was dissolved in DMSO to prepare a 4wt% solution, vacuumed for 0.5h, filtered, and the filtrate was cast on a clean flat plate and then transferred to an oven at 60°C for drying. The prepared membrane was immersed in a 1M NaOH solution for 24 hours, taken out and soaked in water for 24 hours, taken out and dried to obtain a diammonium ion PBI anion membrane.

After testing, the OH ^- conductivity of the diammonium ion PBI anion membrane at 80°C is 50mS/cm, and the ion membrane has good toughness. After immersing in a 1M KOH solution at 80°C for 1300h, the OH ^- ion conductivity remains 82%.

Example 9

Add polyphosphoric acid into a stirred reactor, and under the protection of N ₂ , add benztetramine, oxalic acid and diphenyl ether diacid (the total number of moles of oxalic acid and diphenyl ether diacid is equal to biphenyl). The number of moles of tetraamine) is heated and stirred to dissolve so that the total mass concentration of the monomer is 17% by weight. The temperature was raised to 120°C and stirred for 5 hours, 145°C was reacted for 2 hours, and then the temperature was raised to 170°C for 30 hours, until the viscosity of the system no longer increased. After the polymerization is over, the product is poured into a large amount of deionized water, and excess NaHCO _{3 is} added, and the mixture is stirred overnight. Filter and wash the polymer with deionized water until neutral. The product is dried to obtain polybenzimidazole.

10mol of 1,4-dipiperidinebutane and 8mol of dibromopentane were added to acetonitrile, and the reaction was stirred at 20°C for 30h. After the reaction is completed, it is filtered and dried to obtain the product M'; 10 mol of the above product M'is added to a 30 mol dibromopentane solution in acetonitrile, and reacted at 40°C for 20 hours. After the reaction, the solvent was spun off, filtered and dried to obtain product IV.

10 mol of the synthesized polybenzimidazole was heated and dissolved in NMP to obtain a 10 wt% solution, 15 mol of the above product IV was added, and the reaction was carried out at 50° C. for 24 hours. After the reaction is completed, ethanol is poured into, filtered, the filter cake is washed with deionized water three times, and the product is dried to obtain diammonium ion PBI.

The synthesized diammonium ion PBI was dissolved in DMSO to prepare a 15wt% solution, vacuumed for 0.5h, filtered, and the filtrate was cast on a clean flat plate and then transferred to an oven at 60°C for drying. The prepared membrane was immersed in a 1M NaOH solution for 24 hours, taken out and soaked in water for 24 hours, taken out and dried to obtain a diammonium ion PBI anion membrane.

After testing, the OH ^- conductivity of the diammonium ion PBI anion membrane at 80°C is 45mS/cm, and the ionic membrane has good toughness. After being immersed in a 1M KOH solution at 80°C for 1200h, the OH ^- ion conductivity remains 81%.

Example 10

Add polyphosphoric acid in a stirred reactor, under the protection of N ₂ , add benzhydryl tetraamine, succinic acid and diphenylmethane diacid (the total number of moles of succinic acid and diphenylmethane diacid is equal to The number of moles of benzhydryl tetraamine) is heated and stirred to dissolve so that the total mass concentration of the monomer is 3 wt%. The temperature was raised to 130°C and stirred for 2h, 150°C was reacted for 4h, and then the temperature was raised to 180°C for 6h, until the viscosity of the system no longer increased. After the polymerization is over, the product is poured into a large amount of deionized water, and excess NaHCO _{3 is} added, and the mixture is stirred overnight. Filter and wash the polymer with deionized water until neutral. The product is dried to obtain polybenzimidazole.

10mol of methylpiperazine and 15mol of dibromopentane were added to the dichloroethane, and the temperature was raised to 40°C and the reaction was stirred for 15h. After the reaction is over, filter to obtain product N. Add 10 mol of the above product N to 30 mol of dibromohexane and dichloroethane, and react at 40° C. for 12 h. After the reaction is completed, it is filtered, and the product is centrifuged and dried to obtain product IV.

10 mol of the synthesized polybenzimidazole is heated and dissolved in N-methylpyrrolidone (NMP) to obtain a 10 wt% solution, 15 mol of the above product IV is added, and the reaction is carried out at 40° C. for 15 hours. After the reaction is completed, methanol is poured into, filtered, the filter cake is washed with deionized water three times, and the product is dried to obtain diammonium ion PBI.

The synthesized diammonium ion (PBI) was dissolved in NMP) to prepare a 5 wt% solution, vacuumed for 0.5 h, filtered, and the filtrate was cast on a clean plate to spread a film and transferred to an oven at 60°C for drying. The prepared membrane was immersed in a 1M NaOH solution for 24 hours, taken out and soaked in water for 24 hours, taken out and dried to obtain a diammonium ion PBI anion membrane.

Example 11

Add polyphosphoric acid into a stirred reactor, and under the protection of N ₂ , add biphenyltetraamine, adipic acid and diphenyl ether diacid (the total number of moles of adipic acid and diphenyl ether diacid is equal to biphenyl tetrakis The number of moles of amine) is heated and stirred to dissolve so that the total mass concentration of the monomer is 15 wt%. The temperature was raised to 130°C and stirred for 1 hour, 160°C was reacted for 1 hour, and then the temperature was raised to 190°C to react for 15 hours, until the viscosity of the system no longer increased. After the polymerization is over, the product is poured into a large amount of deionized water, and excess NaHCO _{3 is} added, and the mixture is stirred overnight. Filter and wash the polymer with deionized water until neutral. The product is dried to obtain polybenzimidazole.

10mol of 1,3-dipiperidine propane and 100mol of dibromopentane were added to acetone, and the reaction was stirred at 50°C for 24h. After the reaction is completed, it is filtered and dried to obtain the product M'; 10 mol of the above product M'is added to 100 mol of dibromohexane in tetrahydrofuran solution, and reacted at 60°C for 24 hours. After the reaction, the solvent was spun off, filtered and dried to obtain product IV.

10 mol of the synthesized polybenzimidazole was heated and dissolved in NMP to obtain an 8 wt% solution, 30 mol of the above product IV was added, and the reaction was carried out at 70° C. for 24 hours. After the reaction is over, acetone is poured into, filtered, the filter cake is washed with deionized water three times, and the product is dried to obtain diammonium ion PBI.

After testing, the OH ^- conductivity of the diammonium ion PBI anion membrane at 80°C is 50mS/cm, and the ionic membrane has good toughness. After immersing in a 1M KOH solution at 80°C for 1200h, the OH ^- ion conductivity remains 83%.

Example 12

Add polyphosphoric acid in a stirred reactor, under the protection of N ₂ , add biphenyltetraamine, oxalic acid and biphenyl diphthalic acid (the total number of moles of oxalic acid and biphenyl diphthalic acid is equal to benztetramine The number of moles), heating and stirring to dissolve, so that the total mass concentration of the monomer is 12wt%. The temperature was raised to 100°C and stirred for 7 hours, at 150°C for 3 hours, and then heated to 170°C for 30 hours, until the viscosity of the system no longer increased. After the polymerization is over, the product is poured into a large amount of deionized water, and excess NaHCO _{3 is} added, and the mixture is stirred overnight. Filter and wash the polymer with deionized water until neutral. The product is dried to obtain polybenzimidazole.

10mol methylpiperazine and 10mol dibromopentane were added to acetone, and the temperature was raised to 30°C and the reaction was stirred for 15h. After the reaction is over, filter to obtain product N. 10 mol of the above product N was added to 20 mol of dibromobutane in dichloroethane, and reacted at 50° C. for 10 hours. After the reaction is completed, it is filtered, and the product is centrifuged and dried to obtain product IV.

10 mol of the synthesized polybenzimidazole was heated and dissolved in NMP to obtain a 7 wt% solution, 60 mol of the above product IV was added, and the reaction was carried out at 40° C. for 15 hours. After the reaction is completed, methanol is poured into, filtered, the filter cake is washed with deionized water three times, and the product is dried to obtain diammonium ion PBI.

The synthesized diammonium ion PBI was dissolved in NMP to prepare an 8wt% solution, vacuumed for 0.5h, filtered, and the filtrate was cast on a clean flat plate and then transferred to an oven at 60°C for drying. The prepared membrane was immersed in a 1M NaOH solution for 24 hours, taken out and soaked in water for 24 hours, taken out and dried to obtain a diammonium ion PBI anion membrane.

After testing, the OH ^- conductivity of the bisammonium PBI anion membrane at 80°C is 45mS/cm, and the ion membrane has good toughness. After immersing in a 1M KOH solution at 80°C for 1200h, the OH ^- ion conductivity remains 82%.

Analysis of the hydrogen nuclear magnetic spectrum of Figure 1:

Figure 1 is the hydrogen nuclear magnetic spectrum of bromomethyl piperazine spirocyclic ammonium, the nuclear magnetic frequency is 400MHZ, and the solvent is D ₂ O.

The characteristic peak at 3.478ppm is the chemical shift of H1 on -CH ₂ connected with -Br; the characteristic peak at 3.276ppm is the chemical shift of H2 on -CH ₃ connected with N positive ion (-N ⁺ -); 3.802ppm, 3.683 The characteristic peaks at ppm and 3.559 ppm are the chemical shifts of H3, H4, and H5 on the -CH ₂ connected to -N ⁺ -in the side chain piperazine spiro ring; the characteristic peaks at 1.897 ppm and 1.690 ppm are the piperazine spiro ring- The chemical shifts of H6 and H7 on the meta and para positions of N ⁺ --CH ₂ ; the characteristic peak at 3.599 ppm is the chemical shift of H8 on -CH ₂ connected to -N ⁺ -outside the ring; 1.835 ppm, 1.749 ppm, The characteristic peaks at 1.455 ppm and 1.396 ppm are the chemical shifts of H9, H10, H11, and H12 on the long side chain -CH ₂ . It can be seen that the bromopiperazine spirocyclic ammonium was successfully synthesized.

Figure 2 shows the analysis of the hydrogen nuclear magnetic spectrum:

Figure 2 is a hydrogen nuclear magnetic spectrum of methylpiperazine spiro ring grafted PBI, the nuclear magnetic frequency is 400MHZ, and the solvent is DMSO-d ₆ .

There is no characteristic peak of PBI benzimidazole ring NH at 11-15ppm, indicating that the reaction of PBI grafting piperazine spiro ring has occurred. The characteristic peak at 8.286 ppm is the chemical shift of H2 near the ether bond-O-benzene ring; the characteristic peak at 7.312 ppm is the chemical shift of H1 on the benzene ring far from the ether bond; at 7.990 ppm, 7.850 ppm and 7.626 ppm The peaks are the chemical shifts of H3, H4, and H5 on the benzene ring; the characteristic peak at 2.545 ppm is that after the grafting reaction of N-methylpiperazine spirocyclic ammonium with PBI, it is connected to the double bond N in the PBI benzimidazole ring -CH ₂ The chemical shift of H6 on the upper part; the characteristic peak at 2.384 ppm is the chemical shift of H7 on the -CH ₂ connected to the N atom of the PBI benzimidazole ring after the graft reaction of N-methylpiperazine spirocyclic ammonium with PBI. From the above analysis, it can be seen that the N-methylpiperazine spiro ring is grafted onto the PBI molecular chain, thus successfully preparing the PBI anion exchange membrane with methylpiperazine spiro ammonium side chain.

Analysis of the hydrogen nuclear magnetic spectrum of Figure 3:

Figure 3 is the hydrogen nuclear magnetic spectrum of the ion membrane after dipiperidine spirocyclic ammonium grafted with PBI. The nuclear magnetic frequency is 400MHZ and the solvent is DMSO-d ₆ . It can be seen from Figure 3 that there is no characteristic peak of NH in the imidazole ring between 11-15 ppm, indicating that the NH in the imidazole ring has undergone a substitution reaction. 7-9ppm is the characteristic peak of H on the benzene ring, at 8.33ppm and 7.41ppm are the characteristic peaks of H2 and H1 on the benzene ring directly connected to the ether bond -O-, at 8.14ppm, 8.02ppm, 7.87ppm The characteristic peaks of H3, H4 and H5 on the benzene ring directly connected to the imidazole ring. 2.54ppm and 2.40ppm are the characteristic peaks of H6 and H7 on CH ₂ directly connected to N. 3.82ppm and 3.20ppm are the characteristic peaks of H9 and H8 on CH ₂ connecting piperidine spiro ring to N positive ion. 1.97ppm and 1.57ppm are the characteristic peaks of H10 and H11 in the meta position and para position CH ₂ of the N positive ion in the piperidine spiro ring. From the above analysis, it can be seen that dipiperidine spiro ammonium has been grafted onto the PBI molecular chain, thus successfully preparing a PBI anion exchange membrane with dipiperidine spiro ammonium side chain.

Claims

A bicyclic ammonium ion polybenzimidazole, characterized in that it has the following general formula (I) structure:

Among them, in (I), n=0～0.8;

Z is Cl -, Br -, or OH - ions;

A is a single bond, methylene -CH 2 -, ether bond -O- or carbonyl -CO-;

X is the aliphatic structure:
Among them, 2≤n'≤18;

Y is selected from one of the following structures:

G is a spirocyclic ammonium ion, selected from one of the following structures:

An integer of 0≤y≤12, and an integer of 0<q≤12.
The method for preparing bicyclic ammonium ion polybenzimidazole according to claim 1, characterized in that it comprises the following steps:

Step 1. Synthesis of polybenzimidazole

The polybenzimidazole is synthesized from tetraamine monomer (II) and diacid monomer (III) through solution polycondensation;

The structure of the tetraamine monomer (II) is as follows:

Wherein, A is a single bond, methylene -CH 2 -, ether bond -O- or carbonyl -CO-;

The structure of the diacid monomer (III) is as follows:

HOOC-X-COOH and HOOC-Y-COOH

Among them, X is an aliphatic structure:
Among them, 2≤n'≤18;

Y is selected from one of the following structures:

Add polyphosphoric acid into a stirred reactor. Under the protection of N 2 , add tetraamine monomer (Ⅱ) and diacid monomer (Ⅲ) HOOC-X-COOH and HOOC-Y-COOH in equal molar ratio. Stir and dissolve so that the total mass concentration of monomers II and III is 1-20wt%; increase the temperature to 90-140℃, stir and react for 0.5-10h, then increase the temperature to 140-160℃, stir and react for 0.5-10h, and increase the temperature to 160～190℃ The reaction is 8-30h; the polymerization reaction is over, the product is poured into a large amount of deionized water, excess NaHCO 3 is added, and the mixture is stirred overnight; filtered and washed with deionized water until the polymer is neutral; the product is dried to obtain polybenzimidazole;

Step 2-1, Synthesis of halogenated spirocyclic ammonium salt (Ⅳ)

A certain amount of piperazine or methyl-piperazine is added to the solvent 1 of dibromopentane, the basic compound 2 is added, and the temperature is raised to 30-90°C and the reaction is stirred for 6-72h; the reaction is over, filtered to obtain N;

Add a certain amount of the above synthesized N to a certain amount of dihaloalkane P-(CH 2 ) w -P in solvent 1, add basic compound 2 and react at 30-90℃ for 4-100h. After the reaction is completed, filter the product. Centrifugal drying to obtain IV; wherein, P is selected from Cl or Br atoms, and an integer of 0<w≤12;

Step 2-2, Synthesis of halogenated spirocyclic ammonium salt (Ⅴ)

Add a certain amount of 1,ω-dipiperidine alkane (M) to a certain amount of dihaloalkane P-(CH 2 ) 5 -P (P is Cl or Br atom) in solvent 1, add basic compound 2 in React at 30～90℃ for 4～100h. After the reaction, filter and dry to obtain M'; add a certain amount of M'to a certain amount of P-(CH 2 ) m -P in the solution of solvent 2 at 30～90 React at ℃ for 6-100h, after the reaction is completed, the solvent is evaporated, filtered and dried to obtain V; wherein P is selected from Cl or Br atom, and m is an integer of 0<m≤12,

Step 3. Synthesis of bicyclic ammonium ion polybenzimidazole (Ⅰ)

Heat and dissolve a certain amount of polybenzimidazole in solvent 2 to obtain 0.5-10wt% solution, add halogenated spirocyclic ammonium salt (IV) or halogenated spirocyclic ammonium salt (Ⅴ), and react at 30～150℃ for 8～100h ; The reaction is over, pour into the precipitant 1, filter, wash the filter cake with deionized water, and dry the product to obtain I; dissolve I in solvent 1 to make a 0.5-15% solution to obtain a bicyclic ammonium ion polybenzimidazole electrolyte .
The preparation method according to claim 2, wherein the solvent 2 is toluene, dichloromethane, tetrahydrofuran, methanol, ethanol, N,N-dimethylacetamide, dimethylsulfoxide, N,N- One or a mixture of dimethylformamide and N-methylpyrrolidone;

The solvent 3 is one of dichloromethane, acetone, methanol, ethanol, N,N-dimethylacetamide, dimethylsulfoxide, N,N-dimethylformamide, and N-methylpyrrolidone Or a mixture of several.
The preparation method according to claim 2, characterized in that, in step 2-1, the molar ratio of piperazine or methyl-piperazine to dibromopentane is 0.05-1:1, piperazine or methyl-piperazine The molar ratio of oxazine to basic compound 2 is 0.1～1:1; the molar ratio of N and dihaloalkane P-(CH 2 ) w -P is 0.05～1:1, 2≤w≤8;

In step 2-2, the molar ratio of 1,ω-dipiperidine alkane M to dihaloalkane P-(CH 2 ) m -P is 1:1 to 0.1, and the ratio of M'to P-(CH 2 ) m -P The molar ratio is 0.05-1:1; the molar ratio of 1,ω-dipiperidine alkane M to the basic compound 2 is 0.1-1:1;

The molar ratio of polybenzimidazole to IV in step 3 is 0.1-2:1.
The preparation method according to claim 2, wherein the precipitating agent 1 is one or a mixture of methanol, ethanol, ether, ethyl acetate, dichloromethane, tetrahydrofuran, acetone and water;

The basic compound 2 is selected from one or more of sodium bicarbonate, potassium bicarbonate, sodium carbonate, potassium carbonate, cesium carbonate, sodium hydride, and lithium hydride.
The polybenzimidazole according to claim 1 or the preparation method according to claim 2, wherein the viscosity average molecular weight of the polybenzimidazole is 10,000-450,000 g/mol, and the degree of polymerization n is 20-1200.
A preparation method of bicyclic ammonium ion polybenzimidazole anion exchange membrane, characterized in that: the bicyclic ammonium ion polybenzimidazole I in claim 1 is dissolved in solvent 1 to prepare a 1-15wt% solution, filtered, and the filtrate is cast on Lay the membrane on a clean plate and transfer it to an oven to dry; put the prepared membrane in 1M NaOH or 1M KOH aqueous solution for 24～48h for OH - ion exchange, take it out and soak in water for 24～48h, take out the membrane and dry it to obtain a double ring Ammonium ion polybenzimidazole anion exchange membrane.
The preparation method according to claim 2 or 7, characterized in that the solvent 1 is selected from the group consisting of toluene, methanol, ethanol, dichloromethane, tetrahydrofuran, acetonitrile, acetone, ethyl acetate, N,N-dimethylacetamide , Dimethyl sulfoxide, N,N-dimethylformamide, N-methylpyrrolidone or a mixture of several.
The bicyclic ammonium ion polybenzimidazole according to claim 1 is used as an electrolyte in the fields of fuel cells, flow batteries, water electrolysis, electrodialysis and membrane separation.
The bicyclic ammonium ion polybenzimidazole anion exchange membrane obtained by the preparation method of claim 7 or 8 is used in the fields of fuel cells, flow batteries, water electrolysis, electrodialysis and membrane separation.