Ultramicroporous branched polyaryl piperidinyl anion exchange membrane material as well as preparation method and application thereof

Abstract

The invention discloses an ultra-microporous branched polyaryl piperidinyl anion exchange membrane material as well as a preparation method and application thereof, and relates to the field of anion exchange membrane materials for producing hydrogen by electrolyzing water. According to the ultra-microporous branched polyaryl piperidinyl anion exchange membrane material, a four-functionality branching agent with a structure shown in a formula I is introduced into a polymer structural unit of polyterphenyl piperidone, and a polyaryl piperidinyl compound with a four-branch norbornene bis-benzocyclobutane structure is formed. By adopting the technical scheme, the structural rigidity of a polymer skeleton is improved, the formation of a large number of ultra-microporous structures is promoted, the ionic conductivity of the membrane material is effectively improved, and meanwhile, the problem of relatively poor dimensional stability caused by excessive water absorption of the membrane material is solved; the prepared anion exchange membrane has a wide application prospect in the field of hydrogen production by water electrolysis.

Description

TECHNICAL FIELD

[0001] The application relates to an anion exchange membrane material, in particular to an ultramicroporous branched polyaryl piperidine-based anion exchange membrane material and a preparation method and application thereof, and belongs to the technical field of alkaline water electrolysis. BACKGROUND

[0002] Hydrogen energy is considered to have broad application prospects. In addition to being environmentally friendly, the heat value of hydrogen is higher than that of most fuels, and hydrogen is widely used in industrial, energy, transportation, commercial building and other fields. Most of the hydrogen is produced by reforming fossil fuels such as natural gas and coal in industry. With the progress of scientific research, water electrolysis provides a relatively fast and convenient way to produce hydrogen. At present, water electrolysis technology can be divided into four categories. Among them, alkaline water electrolysis (AWE) and proton exchange membrane water electrolysis (PEMWE) technology are relatively mature, solid oxide water electrolysis technology (SOE) requires high working temperature, and anion exchange membrane water electrolysis technology (AEMWE) has great development potential.

[0003] As the core path of green hydrogen production, the development of anion exchange membrane water electrolysis technology has strategic significance for reducing the cost of electrolytic cell and improving the efficiency of hydrogen production. Traditional proton exchange membrane electrolytic cell relies on noble metal catalysts, while AEM electrolytic cell can use non-noble metal catalysts (such as nickel and iron-based materials) in weak alkaline environment, which significantly reduces the system cost by 30%-50%. However, AEM faces three technical barriers in long-term operation: first, the OH ion conductivity is lower than that of PEM, and the electrolysis efficiency is not high; second, the cationic group is easily attacked by nucleophilic attack in alkaline environment, leading to chemical degradation, and the quaternary ammonium salt group is easily deactivated in high-temperature strong alkaline environment; third, the traditional anion exchange membrane material has high water absorption rate, leading to serious swelling, which seriously affects the dimensional stability of the material.

[0004] Chinese invention patent CN119219901A discloses the preparation and application of a branched poly(aryl piperidine)-based anion exchange membrane material with high free volume. The invention introduces a branching agent 9,9-diphenylfluorene into the polymer structural unit, thereby providing a branched anion exchange membrane structure to increase the free volume inside the membrane material, limit the movement ability of part of the chain segments, and inhibit the swelling of the membrane material due to water absorption, effectively improving the ion conductivity and dimensional stability of the membrane material. The prepared anion exchange membrane can be applied to water electrolysis for hydrogen production.

[0005] The application further improves the prior art, and provides a kind of supermicroporous branched polyaryl piperidine-based anion exchange membrane material containing norbornene double benzocyclobutane structure, in which polyaryl piperidine-based polymer is used as main chain, and another tetrad type compound is used as branching agent, which can effectively improve the chemical stability of membrane material, improve the structural rigidity of polymer skeleton, promote the formation of a large number of supermicroporous structures, effectively improve the ion conductivity of membrane material, and inhibit the problem of poor dimensional stability caused by excessive water absorption of membrane material.The prepared anion exchange membrane has wide application prospect in the field of water electrolysis hydrogen production. SUMMARY

[0006] The main purpose of the application is to provide a kind of supermicroporous branched polyaryl piperidine-based anion exchange membrane material and its preparation method and application, to overcome the deficiencies in the prior art.

[0007] To achieve the above-mentioned purposes, the application adopts the following technical solutions.

[0008] As one aspect of the application, a branching agent is provided, which has the following structural formula:

[0009]

[0010] As one aspect of the application, a preparation method of the branching agent is provided, which includes the following steps: mixing 1-bromo-3,5-diphenylbenzene, 2,5-norbornadiene, palladium acetate, triphenylphosphine and cesium carbonate, then adding them into dioxane and stirring uniformly, heating to 120-180℃ until the reaction is completed, cooling to room temperature, and then purifying to obtain white solid powder, which is the branching agent; the branching agent is a mixture of isomers of (1,3,7,9-tetraphenyl-4b,5,5a,9b,10,10a-hexahydro-5,10-methylbenzo[3,4]cyclobutano[1,2-b]biphenyl / 1,3,6,8-tetraphenyl-4b,5,5a,9b,10,10a-hexahydro-5,10-methylbenzo[3,4]cyclobutano[1,2-b]biphenyl.

[0011] As one of the aspects of the invention, the present invention provides a kind of ultra-microporous branched polyaryl piperidine-based anion exchange membrane material, which includes introducing tetra-functionality 1,3,7,9-tetraphenyl-4b,5,5a,9b,10,10a-hexahydro-5,10-methyl benzo [3,4] cyclobuteno [1,2-b] biphenyl and 1,3,6,8-tetraphenyl-4b,5,5a,9b,10,10a-hexahydro-5,10-methyl benzo [3,4] cyclobuteno [1,2-b] biphenyl (as isomers) as branching agents into the polymer structure unit of polytriphenyl piperidine ketone, to form branched polyaryl piperidine-based compounds containing norbornene double benzocyclobutane structure with a four-way structure.

[0012] As a preferred embodiment, the ultra-microporous branched polyaryl piperidine-based anion exchange membrane material has a general structure as shown in formula (I):

[0013]

[0014] In the formula, x+y is the structure unit of the branched part, and each branched part contains two piperidine cation structures in the unit structure; the number of structure units of the linear part is n, n=n1+n2+n3+n4, wherein n1=0-0.97, n2=0-0.97, n3=0-0.97, n4=0-0.97; and x+y=0.005-0.03, n=0.97-0.995.

[0015] As a preferred embodiment, the molecular weight of the ultra-microporous branched polyaryl piperidine-based anion exchange membrane material is 50-100 kDa.

[0016] As a preferred embodiment, the water absorption rate at 30℃ is 29-38%, and the OH- conductivity is 70-85 mS cm -1 ; the water absorption rate at 80℃ is 30-41%, and the OH - conductivity is 135-150 mS cm -1 .

[0017] As one of the aspects of the invention, the present invention also provides a kind of preparation method of ultra-microporous branched polyaryl piperidine-based anion exchange membrane material, which includes: reacting protonated ultra-microporous branched polyaryl piperidine-based polymer with iodomethane to obtain the ultra-microporous branched polyaryl piperidine-based anion exchange membrane material containing norbornene double benzocyclobutane structure as shown in formula 1;

[0018] In the formula, the structure formula of the protonated ultra-microporous branched polyaryl piperidine-based polymer is shown in formula (II):

[0019]

[0020] wherein x+y is the structural unit of the branched part, and each branched part contains two piperidinium cation structures in the unit structure; the number of the structural unit of the linear part is n, n=n1+n2+n3+n4, wherein n1=0-0.97, n2=0-0.97, n3=0-0.97, n4=0-0.97, and the molecular weight=50-100 kDa; and x+y=0.005-0.03, n=0.995-0.97.

[0021] Preferably, the preparation method comprises: dissolving the protonated hyper-porous branched polyarylpiperidine-based polymer in a first organic solvent, adding methyl iodide for reaction, then precipitating the reaction product in a second organic solvent, filtering and drying, dissolving again in a third organic solvent, uniformly coating on a substrate and drying, and performing ion exchange to obtain the hyper-porous branched polyarylpiperidine-based anion exchange membrane containing norbornene bis-benzocyclobutane structure as shown in formula 1.

[0022] As a preferred embodiment, the reaction temperature is 50°C, and the reaction time is 48-72 hours.

[0023] As a preferred embodiment, the first organic solvent is dimethyl sulfoxide;

[0024] As a preferred embodiment, the first organic solvent is 50-100 times the mass of the protonated hyper-porous branched polyarylpiperidine-based polymer;

[0025] As a preferred embodiment, the second organic solvent is ethyl acetate;

[0026] As a preferred embodiment, the amount of the second organic solvent is 10-20 times the volume of the first organic solvent;

[0027] As a preferred embodiment, the third organic solvent is dimethyl sulfoxide;

[0028] As a preferred embodiment, the amount of the third organic solvent is 30-40 times the mass of the hyper-porous branched polyarylpiperidine-based anion exchange membrane material.

[0029] As a preferred embodiment, the preparation method of the protonated hyper-porous branched polyarylpiperidine-based polymer comprises: performing superacid catalytic reaction on compound (a), compound (b), and compound (c), precipitating in methanol, filtering and drying to obtain the product; the structures of compound (a), compound (b), and compound (c) are as shown below:

[0030]

[0031] As a preferred embodiment, the preparation method of the protonated hyperporous branched polyaryl-piperidine-based polymer comprises: adding compound (a), compound (b), compound (c) into a fourth organic solvent to dissolve, then adding a catalyst, and performing a protonation reaction at 0°C; after the reactants are precipitated in methanol, they are washed and dried to obtain the product.

[0032] Preferably, the catalyst is trifluoroacetic acid and trifluoromethanesulfonic acid.

[0033] Preferably, the fourth organic solvent is dichloromethane.

[0034] Preferably, the amount of the fourth organic solvent is 2-5 times the total mass of compound (a), compound (b), and compound (c).

[0035] Preferably, the reaction time of the protonation reaction is 4-6 hours.

[0036] Preferably, the addition ratio of compound (a), compound (b), and compound (c) is 0.5-3:97-99.5:110.

[0037] As one of the purposes of the application, the application also provides an application of the hyperporous branched polyaryl-piperidine-based anion exchange membrane material as described above in an alkaline water electrolyzer.

[0038] As one of the purposes of the application, the application also provides an alkaline water electrolyzer comprising an electrolyte diaphragm, wherein the electrolyte diaphragm comprises the hyperporous branched polyaryl-piperidine-based anion exchange membrane material as described above.

[0039] Compared with the prior art, the application has at least the following beneficial effects:

[0040] 1) The application provides a hyperporous branched polyaryl-piperidine-based anion exchange membrane material containing a norbornene bis-benzocyclobutane structure on the basis of the prior art, which uses a polyaryl-piperidine-based polymer as a main chain and introduces 1,3,6,8-tetraphenyl-4b,5,5a,9b,10,10a-hexahydro-5,10-methylbenzo[3,4]cyclobutano[1,2-b]biphenyl / 1,3,7,9-tetraphenyl-4b,5,5a,9b,10,10a-hexahydro-5,10-methylbenzo[3,4]cyclobutano[1,2-b]biphenyl as a branching agent. This “four-branched” branching agent can effectively improve the chemical stability of the membrane material, increase the structural rigidity of the polymer skeleton, promote the formation of a large number of hyperporous structures, effectively improve the ion conductivity of the membrane material, and at the same time inhibit the problem of poor dimensional stability caused by excessive water absorption of the membrane material. The prepared anion exchange membrane has a wide application prospect in the field of electrolytic water hydrogen production.

[0041] 2) The ultramicroporous branched polyarylpiperidinyl polymer containing norbornene dibenzocyclobutane structure provided by the present invention is prepared by superacid-catalyzed Friedel-Crafts reaction, and can be directly used to prepare anion exchange membranes by casting. The prepared anion exchange membrane has good ionic conductivity, dimensional stability and chemical stability, and has good application prospects in the field of hydrogen production in alkaline water electrolyzers. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 The synthetic route of the ultramicroporous branched polyarylpiperidinyl anion exchange membrane material containing norbornene dibenzocyclobutane structure provided by the present invention is shown.

[0044] Figure 2 The NMR spectra are those of the ultramicroporous branched polyarylpiperidinyl anion exchange membranes containing norbornene dibenzocyclobutane structures described in Example 4 and Comparative Example 1 of this invention.

[0045] Figure 3 The diagram shows the OH- ion conductivity of the ultramicroporous branched polyarylpiperidine anion exchange membrane material containing a norbornene dibenzocyclobutane structure provided in Comparative Example 1 and Examples 1 to 4 of this invention.

[0046] Figure 4 The CO2 adsorption-desorption curves are shown for the ultramicroporous branched polyarylpiperidine anion exchange membrane materials containing norbornene dibenzocyclobutane structure provided in Comparative Example 1 and Examples 1 to 4 of the present invention.

[0047] Figure 5 The micropore size distribution diagrams are shown for the ultramicroporous branched polyarylpiperidine anion exchange membrane materials containing norbornene dibenzocyclobutane structures provided in Comparative Example 1 and Examples 1 to 4 of the present invention.

[0048] Figures 6a-6e The images are TEM images of the ultramicroporous branched polyarylepiperidinyl anion exchange membrane materials containing norbornene dibenzocyclobutane structure provided in Examples 1 to 4 and Comparative Example 1 of the present invention.

[0049] Figure 7 The NMR spectrum of the branching agent prepared in Example 1 of this invention is shown. Detailed Implementation

[0050] The technical scheme, implementation process and principles will be further explained as follows. However, it should be understood that the above technical features of the present application and the technical features specifically described below (in the examples) can be combined with each other to form new or preferred technical schemes within the scope of the present application, and will not be described one by one here due to the limited space.

[0051] The present application provides a branching agent, comprising a structural formula as shown below:

[0052]

[0053] The present application also provides a preparation method of the branching agent with the above structural formula, and the specific scheme comprises the following steps: 1-bromo-3, 5-diphenylbenzene, 2, 5-norbornadiene, palladium acetate, triphenylphosphine and cesium carbonate are mixed, then added into dioxane and stirred uniformly, heated to 120-180℃ until the reaction is completed, cooled to room temperature, and then purified to obtain white solid powder, which is the branching agent; the branching agent is an isomer mixture of (1, 3, 7, 9-tetraphenyl-4b, 5, 5a, 9b, 10, 10a-hexahydro-5, 10-methylbenzo[3, 4] cyclobutano[1, 2-b] biphenyl / 1, 3, 6, 8-tetraphenyl-4b, 5, 5a, 9b, 10, 10a-hexahydro-5, 10-methylbenzo[3, 4] cyclobutano[1, 2-b] biphenyl.

[0054] Exemplarily, the present application provides one specific example of the preparation method of the above branching agent, and the specific steps comprise the following steps: 1-bromo-3, 5-diphenylbenzene (6.1842g, 20mmol), 2, 5-norbornadiene (0.9214g, 10mmol), palladium acetate (0.0449g, 0.2mmol), triphenylphosphine (0.1049g, 0.4mmol) and cesium carbonate (6.5164g, 20mmol) are added into a 350mL pressure-resistant bottle, and then 100mL dioxane is added to stir uniformly.

[0055] The reaction is continued for 72 hours at 150℃, after cooling to room temperature, extraction is performed with dichloromethane, then filtration, rotary evaporation, and column chromatography (developing agent: pure petroleum ether) is used for separation and purification to obtain white solid powder (an isomer mixture of 1, 3, 7, 9-tetraphenyl-4b, 5, 5a, 9b, 10, 10a-hexahydro-5, 10-methylbenzo[3, 4] cyclobutano[1, 2-b] biphenyl / 1, 3, 6, 8-tetraphenyl-4b, 5, 5a, 9b, 10, 10a-hexahydro-5, 10-methylbenzo[3, 4] cyclobutano[1, 2-b] biphenyl), and the yield is 46%.

[0056] As an aspect of the technical scheme of the present application, the ultra-microporous branched polyaryl-piperidine-based anion exchange membrane material containing norbornene double benzocyclobutane structure has the structure shown in formula (I).

[0057]

[0058] In the formula, the structural unit of the branched part is x+y, and each branched part contains two piperidine cation structures, and the number of the structural unit of the linear part is n (n=n1+n2+n3+n4), wherein n1=0-0.97, n2=0-0.97, n3=0-0.97, n4=0-0.97, and the molecular weight is 50-100 kDa; x+y=0.005-0.03, n=0.995-0.97, and the molecular weight is 50-100 kDa.

[0059] The present application also provides a preparation method of the ultra-microporous branched polyaryl-piperidine-based anion exchange membrane material containing norbornene double benzocyclobutane structure as described above, which comprises: reacting the ultra-microporous branched polyaryl-piperidine-based polymer protonated by trifluoroacetic acid shown in formula (II) with iodomethane (CH3I) to obtain the ultra-microporous branched polyaryl-piperidine-based anion exchange membrane material containing norbornene double benzocyclobutane structure shown in formula (I). For details, see Figure 1 The synthesis route map of the ultra-microporous branched polyaryl-piperidine-based anion exchange membrane material.

[0060] In the formula, the structural unit of the branched part is x+y, and each branched part contains two piperidine cation structures, and the number of the structural unit of the linear part is n (n=n1+n2+n3+n4), wherein n1=0-0.97, n2=0-0.97, n3=0-0.97, n4=0-0.97, and the molecular weight is 50-100 kDa; x+y=0.005-0.03, n=0.995-0.97.

[0061] Preferably, a certain amount of the ultra-microporous branched polyaryl-piperidine-based polymer protonated by trifluoroacetic acid shown in formula (II) is dissolved in an organic solvent at 50°C, then iodomethane is added, after the reaction is completed, the reactants are settled in the organic solvent, filtered and dried. Then it is dissolved in an organic solvent, uniformly coated on a substrate and dried, and then ion exchanged to obtain the ultra-microporous branched polyaryl-piperidine-based anion exchange membrane containing norbornene double benzocyclobutane structure shown in formula (I).

[0062] Preferably, the reaction temperature of the above reaction is 50°C, and the reaction time is 48-72 hours.

[0063] Preferably, the organic solvent used for the reaction is dimethyl sulfoxide (DMSO), and the amount of the organic solvent is 50-100 times the mass of the ultra-microporous branched polyaryl-piperidine-based polymer protonated by trifluoroacetic acid.

[0064] Preferably, the organic solvent used for the precipitation is ethyl acetate, and the amount of the organic solvent is 10-20 times the volume of the organic solvent used in the reaction.

[0065] Preferably, the organic solvent used for the film preparation is dimethyl sulfoxide, and the amount of the organic solvent is 30-40 times the mass of the ultra-microporous branched polyaryl-piperidine-based anion exchange membrane material.

[0066] Preferably, the ultra-microporous branched polyaryl-piperidine-based anion exchange membrane material containing a norbornene bis-benzocyclobutane structure is prepared by the following steps: subjecting three compounds (a), (b), and (c) shown below to an ultra-acid catalytic reaction, precipitating in methanol, filtering, and drying to obtain an ultra-microporous branched polyaryl-piperidine-based polymer protonated by trifluoroacetic acid shown in formula (II).

[0067]

[0068] The specific preparation method is as follows: dissolving the three compounds (a), (b), and (c) in an organic solvent, adding trifluoroacetic acid and triflic acid, and reacting at 0°C for 4-6 hours; precipitating the reaction product in methanol to obtain an ultra-microporous branched polyaryl-piperidine-based polymer protonated by trifluoroacetic acid shown in formula (II).

[0069] Further preferably, the raw materials used are shown in the structural formulae of the compounds (a), (b), and (c), the compound (a) is 1,3,7,9-tetraphenyl-4b,5,5a,9b,10,10a-hexahydro-5,10-methylbenzo[3,4]cyclobutano[1,2-b]diphenyl / 1,3,6,8-tetraphenyl

[0070] -4b,5,5a,9b,10,10a-hexahydro-5,10-methylbenzo[3,4]cyclobutano[1,2-b]diphenyl, the compound (b) is terphenyl, the compound (c) is N-methyl-4-piperidone, and the organic solvent is dichloromethane, and the amount of the organic solvent is 2-5 times the total molar amount of the three compounds (a), (b), and (c); wherein the catalyst is trifluoroacetic acid and triflic acid, the amount of the trifluoroacetic acid is 1-5 times the molar amount of the compound (c), and the amount of the triflic acid is 10-15 times the molar amount of the compound (c); the reaction temperature is 0°C, the reaction time is 4-6 hours, and the drying temperature is 80°C.

[0071] The main design idea of the present application is as follows:

[0072] The polyaryl piperidinyl polymer is selected as the main chain, which can effectively improve the chemical stability of the membrane material. Further, 1, 3, 6, 8-tetraphenyl-4b, 5, 5a, 9b, 10, 10a-hexahydro-5, 10-methylbenzo [3, 4] cyclobuteno [1, 2-b] biphenyl / 1, 3, 7, 9-tetraphenyl

[0073] -4b, 5, 5a, 9b, 10, 10a-hexahydro-5, 10-methylbenzo [3, 4] cyclobuteno [1, 2-b] biphenyl is used as a branching agent. The introduction of this "quadrifurcation" type branching agent can improve the structural rigidity of the polymer skeleton. In the obtained product, it is found that the introduction of the "quadrifurcation" type branching agent promotes the formation of a large number of ultramicroporous structures.

[0074] The following will be specifically described in combination with specific examples. It is necessary to point out here that the following examples are only used to further illustrate the present application and cannot be understood as limiting the protection scope of the present application. Some non-essential improvements and adjustments made by those skilled in the art according to the content of the present application still fall within the protection scope of the present application.

[0075] The raw materials used in the embodiments of the present application are all purchased from the market.

[0076] The instruments and equipment used in the following examples are all conventional equipment in the relevant field, and the performance tests are all carried out according to the requirements of the conventional standards.

[0077] Example 1

[0078] The present embodiment provides a preparation method of an ultramicroporous branched polyaryl piperidinyl anion exchange membrane material containing a norbornene double benzocyclobutane structure. Referring to Figure 1 , which is a schematic diagram of the principle of preparation. Specifically, the preparation method comprises the following steps:

[0079] (1) Preparation of the branching agent

[0080] The branching agent used in this example is a mixture of isomers of 1,3,7,9-tetraphenyl-4b,5,5a,9b,10,10a-hexahydro-5,10-methanobenzo[3,4]cyclobuta[l,2-b]diphenyl / 1,3,6,8-tetraphenyl-4b,5,5a,9b,10,10a-hexahydro-5,10-methanobenzo[3,4]cyclobuta[l,2-b]diphenyl, specifically, the preparation method comprises: adding 1-bromo-3,5-diphenylbenzene (6.1842 g, 20 mmol), 2,5-norbornadiene (0.9214 g, 10 mmol), palladium acetate (0.0449 g, 0.2 mmol), triphenylphosphine (0.1049 g, 0.4 mmol) and cesium carbonate (6.5164 g, 20 mmol) into a 350 mL pressure-resistant bottle, and then adding 100 mL of dioxane to stir uniformly, reacting at 150°C for 72 hours, after cooling to room temperature, extracting with dichloromethane, filtering, rotary evaporation, and separating and purifying by column chromatography (eluent: pure petroleum ether) to obtain a white solid powder (a mixture of isomers of 1,3,7,9-tetraphenyl-4b,5,5a,9b,10,10a-hexahydro-5,10-methanobenzo[3,4]cyclobuta[l,2-b]diphenyl / 1,3,6,8-tetraphenyl-4b,5,5a,9b,10,10a-hexahydro-5,10-methanobenzo[3,4]cyclobuta[l,2-b]diphenyl), with a yield of 46%.

[0081] Reference is made to Figure 7 The preparation of the branching agent (containing isomers) is 1 H NMR spectrum.

[0082] (2) Preparation of ultra-microporous branched polyaryl-piperidine-based polymers protonated by trifluoroacetic acid

[0083] Into a three-necked flask with mechanical stirring, 1,3,7,9-tetraphenyl-4b,5,5a,9b,10,10a-hexahydro-5,10-methanobenzo[3,4]cyclobuta[l,2-b]diphenyl / 1,3,6,8-tetraphenyl-4b,5,5a,9b,10,10a-hexahydro-5,10-methanobenzo[3,4]cyclobuta[l,2-b]diphenyl (0.074 g, 0.05 mmol), terphenyl (2.2915 g, 9.95 mmol), N-methyl-4-piperidone (1.2510 g, 11.06 mmol) were added, and the flask was covered with an ice bath more than half of the volume of the flask. Then 10 mL of dichloromethane and 1 mL of trifluoroacetic acid were added and stirred well. Then 12 mL of trifluoromethanesulfonic acid was added, and the reaction was continued at 0 °C for 4 hours. The highly viscous solution was poured into methanol to precipitate, and the product was cut into pieces and washed with deionized water several times until the pH value was neutral. Finally, it was dried in a vacuum oven at 80 °C for 12 hours to obtain white solid fibers (PTP-C-TP-0.5) with a yield of 92%.

[0084] (3) Preparation of ultra-microporous branched polyaryl piperidine-based anion exchange membrane

[0085] Into a round-bottom flask, PTP-C-TP-0.5 (1 g, 4 mmol) was dissolved in 100 mL of DMSO, and then potassium carbonate (2 g, 15 mmol) and CH3I (9 g, 64 mmol) were added. After the mixed solution was stirred well with a magnetic stirrer, it was reacted at 50 °C for 48 hours in the dark. The resulting solution was filtered, and then the filtrate was poured into 1 L of ethyl acetate to precipitate. Then it was filtered and dried in a vacuum oven at 80 °C for 12 hours to obtain a yellow-brown solid powder (QPTP-C-TP-0.5) with a yield of 88%.

[0086] Example 2

[0087] Reference Figure 1 The present embodiment provides a method for preparing an ultra-microporous branched polyaryl piperidine-based anion exchange membrane material containing a norbornene bisbenzocyclobutane structure, comprising the following steps:

[0088] (1) Preparation of a branching agent

[0089] This step is the same as that of Example 1.

[0090] (2) Preparation of an ultra-microporous branched polyaryl piperidine-based polymer protonated by trifluoroacetic acid

[0091] Into a three-necked flask with mechanical stirring, 1,3,7,9-tetraphenyl-4b,5,5a,9b,10,10a-hexahydro-5,10-methanobenzo[3,4]cyclobuta[l,2-b]diphenyl / 1,3,6,8-tetraphenyl-4b,5,5a,9b,10,10a-hexahydro-5,10-methanobenzo[3,4]cyclobuta[l,2-b]diphenyl (0.0549 g, 0.1 mmol), terphenyl (2.280 g, 9.9 mmol), N-methyl-4-piperidone (1.2572 g, 11.11 mmol) were added, and the flask was covered with an ice bath more than half of the volume of the flask. Then 10 mL of dichloromethane and 1 mL of trifluoroacetic acid were added and stirred well. Then 12 mL of trifluoromethanesulfonic acid was added, and the reaction was continued at 0 °C for 3 hours. The highly viscous solution was poured into methanol to precipitate, and then the product was cut into pieces and washed with deionized water several times until the pH value was neutral. Finally, it was dried in a vacuum oven at 80 °C for 12 hours to obtain a light yellow solid powder (PTP-C-TP-1) with a yield of 91%.

[0092] (3) Preparation of ultra-microporous branched polyarylpipehdine-based anion exchange membrane

[0093] Into a round-bottom flask, PTP-C-TP-1 (1 g, 4 mmol) was dissolved in 100 mL of DMSO, and then potassium carbonate (2 g, 15 mmol) and CH3I (9 g, 64 mmol) were added. After the mixed solution was stirred well by magnetic stirring, it was reacted at 50 °C for 48 hours in the dark. The resulting solution was filtered, and then the filtrate was poured into 1 L of ethyl acetate to precipitate. Then it was filtered and dried in a vacuum oven at 80 °C for 12 hours to obtain a yellow-brown solid powder (QPTP-C-TP-1) with a yield of 90%.

[0094] Example 3

[0095] This example provides a method for preparing an ultra-microporous branched polyarylpipehdine-based anion exchange membrane material containing a norbornene bisbenzocyclobutane structure, comprising the following steps:

[0096] (1) Preparation of a branching agent

[0097] This step is the same as Example 1.

[0098] (2) Preparation of ultra-microporous branched polyarylpipehdine-based polymer protonated by trifluoroacetic acid

[0099] Into a three-necked flask with mechanical stirring, 1,3,7,9-tetraphenyl-4b,5,5a,9b,10,10a-hexahydro-5,10-methanobenzo[3,4]cyclobuta[l,2-b]diphenyl / 1,3,6,8-tetraphenyl-4b,5,5a,9b,10,10a-hexahydro-5,10-methanobenzo[3,4]cyclobuta[l,2-b]diphenyl (0.1097 g, 0.2 mmol), terphenyl (2.2569 g, 9.8 mmol), N-methyl-4-piperidone (1.2697 g, 11.22 mmol) were added, and the flask was covered with an ice bath more than half of the volume of the flask. Then 10 mL of dichloromethane and 1 mL of trifluoroacetic acid were added and stirred well. Then 12 mL of trifluoromethanesulfonic acid was added, and the reaction was continued at 0 °C for 3 hours. The highly viscous solution was poured into methanol to precipitate, and the product was cut into pieces and washed with deionized water several times until the pH value was neutral. Finally, it was dried in a vacuum oven at 80 °C for 12 hours to obtain a white solid powder (PTP-C-TP-2) with a yield of 93%.

[0100] (3) Preparation of ultra-microporous branched polyaryl piperidine-based anion exchange membrane

[0101] Into a round-bottom flask, PTP-C-TP-2 (1 g, 4 mmol) was dissolved in 100 mL of DMSO, and then potassium carbonate (2 g, 15 mmol) and CH3I (9 g, 64 mmol) were added. After the mixed solution was stirred well with a magnetic stirrer, it was reacted at 50 °C for 48 hours in the dark. The resulting solution was filtered, and then the filtrate was poured into 1 L of ethyl acetate to precipitate. Then it was filtered and dried in a vacuum oven at 80 °C for 12 hours to obtain a yellow-brown solid powder (QPTP-C-TP-2) with a yield of 88%.

[0102] Example 4

[0103] This example provides a method for preparing an ultra-microporous branched polyaryl piperidine-based anion exchange membrane material containing a norbornene bisbenzocyclobutane structure, which is described in detail in Figure 1 (only the trans isomer is shown in the polymer structure), which comprises the following steps:

[0104] (1) Preparation of a branching agent

[0105] This step is the same as that of Example 1.

[0106] (2) Preparation of an ultra-microporous branched polyaryl piperidine-based polymer protonated by trifluoroacetic acid

[0107] Into a three-necked flask with mechanical stirring, 1,3,7,9-tetraphenyl-4b,5,5a,9b,10,10a-hexahydro-5,10-methanobenzo[3,4]cyclobuta[l,2-b]diphenyl / 1,3,6,8-tetraphenyl-4b,5,5a,9b,10,10a-hexahydro-5,10-methanobenzo[3,4]cyclobuta[l,2-b]diphenyl (0.1646 g, 0.3 mmol), terphenyl (2.2339 g, 9.7 mmol), N-methyl-4-piperidone (1.2821 g, 11.33 mmol) were added, and the flask was covered with an ice bath more than half of the volume of the flask. Then 10 mL of dichloromethane and 1 mL of trifluoroacetic acid were added and stirred well. Then 12 mL of trifluoromethanesulfonic acid was added, and the reaction was continued at 0 °C for 3 hours. The highly viscous solution was poured into methanol to precipitate, and then the product was cut into pieces and washed with deionized water several times until the pH value was neutral. Finally, it was dried in a vacuum oven at 80 °C for 12 hours to obtain a light yellow solid powder (PTP-C-TP-3) with a yield of 92%.

[0108] (3) Preparation of ultra-microporous branched polyaryl piperidine-based anion exchange membrane material

[0109] Into a round-bottom flask, PTP-C-TP-3 (1 g, 4 mmol) was dissolved in 100 mL of DMSO, and then potassium carbonate (2 g, 15 mmol) and CH3I (9 g, 64 mmol) were added. After the mixed solution was stirred well with a magnetic stirrer, it was reacted at 50 °C for 48 hours in the dark. The resulting solution was filtered, and then the filtrate was poured into 1 L of ethyl acetate to precipitate. Then it was filtered and dried in a vacuum oven at 80 °C for 12 hours to obtain a yellow-brown solid powder (QPTP-C-TP-3) with a yield of 89%.

[0110] 1 H NMR (DMSO-d6) was shown in FIG. 1. Figure 2

[0111] Comparative Example 1

[0112] The preparation method of the ultra-microporous branched polyaryl piperidine-based anion exchange membrane material containing a norbornene bis-benzocyclobutane structure according to the present comparative example includes the following steps:

[0113] (1) Preparation of ultra-microporous branched polyaryl piperidine-based polymer protonated by trifluoroacetic acid

[0114] ​Triphenyl (2.303 g, 10 mmol), N-methyl-4-piperidone (1.2448 g, 11 mmol) were added into a three-necked flask with mechanical stirring, and the flask was covered by ice bath more than half of the volume. Then 10 mL of dichloromethane and 1 mL of trifluoroacetic acid were added and stirred uniformly. Then 12 mL of trifluoromethanesulfonic acid was added, and the reaction was continued for 3 hours at 0℃. The high-viscosity solution was poured into methanol for precipitation, and then the product was cut into pieces and washed with deionized water for several times until the pH value was neutral. Finally, it was dried in a vacuum oven at 80℃ for 12 hours to obtain a light yellow solid powder (PTP) with a yield of 93%.

[0115] (2) Preparation of ultra-microporous branched polyaryl piperidine-based anion exchange membrane material

[0116] PTP (1 g, 4 mmol) was added into a round-bottom flask and dissolved in 100 mL of DMSO, and then potassium carbonate (2 g, 15 mmol) and CH3I (9 g, 64 mmol) were added. After the mixed solution was uniformly stirred by magnetic stirring, it was reacted at 50℃ for 48 hours in the dark. The obtained solution was filtered, and then the filtrate was poured into 1 L of ethyl acetate for precipitation. Then it was filtered and dried in a vacuum oven at 80℃ for 12 hours to obtain a yellow-brown solid powder (QPTP) with a yield of 90%.

[0117] Referring to Figures 6a-6e , TEM images of the ultra-microporous branched polyaryl piperidine-based anion exchange membrane material containing norbornene double benzocyclobutane structure provided by Example 1 to Example 4 (in order Figure 6a , Figure 6b , Figure 6c , Figure 6d ) and Comparative Example 1 Figure 6e ) are shown in the figure. As can be seen from the figure, Examples 1 to 4 have obvious phase separation structure, which is more conducive to the formation of ion transmission channels, thereby improving ion transmission efficiency and increasing conductivity. Comparative Example 1 shows a more uniform structure, and the phase separation phenomenon is not obvious.

[0118] Referring to Figure 4 , CO2 adsorption and desorption curve diagrams of the ultra-microporous branched polyaryl piperidine-based anion exchange membrane material containing norbornene double benzocyclobutane structure provided by Comparative Example 1 and Examples 1 to 4 are shown in the figure. As can be seen from the figure, the specific surface areas of the materials obtained by Examples 1 to 4 are S = 119 m 2 g -1 , 87 m 2 g -1 , 97 m 2 g -1 , and 65 m 2 g -1 , respectively. The specific surface area of Comparative Example 1 is S = 81 m2 g -1 When a small amount of branched agent content (0.5%) is incorporated, the micropore content of the anion exchange membrane material is greatly increased, and these micropore structures play a dominant role in improving the ionic conductivity; and then as the content gradually increases to 3%, the micropore content of the polymer decreases, but the micropore content of the polymer is still higher than that of the comparative example 1, and the ionic conductivity of the polymer is also higher than that of the comparative example 1, which is mainly due to the fact that the micropore content of the polymer is still higher than that of the comparative example 1. Figure 6d The obvious phase separation structure can still be seen, and therefore the main reason why the conductivity of example 4 is also higher than that of the comparative example 1 is that the phase separation structure plays a dominant role.

[0119] Figure 5 The micropore size distribution diagram of the microporous branched type polyarylpiperidyl anion exchange membrane material containing a norbornene bis-bicyclo ring structure provided by the present application for the comparative example 1 and examples 1-4 can be seen from the figure, and as the branched content increases, the micropore size of the anion exchange membrane material gradually decreases, and is mainly concentrated around 0.55 nm and 0.7 nm.

[0120] The ion exchange capacity IEC of the anion exchange membranes obtained in the comparative example and examples was tested, and the water absorption, the swelling rate and the OH- ion conductivity at 30°C and 80°C were also tested, respectively, and the results are shown in Table 1.

[0121] Table 1 Performance comparison of anion exchange membrane materials obtained in examples and comparative examples

[0122]

[0123] From the results in Table 1, it can be seen that the IEC value of the anion exchange membrane material with a super-microporous structure provided by the present application is similar to that of the comparative example 1, but the water absorption, the swelling rate at 30°C and 80°C are significantly lower than those of the comparative example 1, and the conductivity is significantly higher than that of the comparative example 1, which shows that the anion exchange membrane prepared by using the technical scheme of the present application has very high dimensional stability and mechanical strength, and at the same time, it shows high conductivity characteristics, which shows that the OH- ion transmission efficiency inside the material is high, which can improve its performance, for example, it can improve the efficiency of hydrogen production by electrolysis of water. Obviously, the branched type anion exchange membrane with a super-microporous structure prepared by using a branched agent provided by the present application can effectively improve the chemical stability of the membrane material, the tetra-branching structure of the branched agent not only can improve the structural rigidity of the polymer skeleton, but also can promote the formation of a large number of super-microporous structures, effectively improve the ion conductivity of the membrane material, and at the same time, inhibit the problem of poor dimensional stability caused by excessive water absorption of the membrane material. The prepared anion exchange membrane can significantly improve the hydrogen production efficiency in the field of hydrogen production by electrolysis of water, and has a wider application prospect.

[0124] In addition, the inventors of the present application also refer to the foregoing examples, and other raw materials, process operations, process conditions described in the specification are tested, and ideal results are obtained.

[0125] It should be understood that the above examples and features are only for illustrating the technical concepts and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and to implement it, and cannot limit the protection scope of the present application. Any equivalent transformation or modification made in accordance with the spirit and essence of the present application shall be covered within the protection scope of the present application.

Claims

1. A branching agent, comprising the following structural formula:

2. The branching agent of claim 1, wherein The method for preparing the branching agent includes: 1-Bromo-3,5-diphenylbenzene, 2,5-norbornadiene, palladium acetate, triphenylphosphine and cesium carbonate were mixed and then dioxane was added and stirred until homogeneous. The mixture was heated to 120-180°C until the reaction was complete. After cooling to room temperature, the mixture was purified to obtain a white solid powder, which is the branching agent. The branching agent is a mixture of isomers of (1,3,7,9-tetraphenyl-4b,5,5a,9b,10,10a-hexahydro-5,10-methylbenzo[3,4]cyclobutano[1,2-b]biphenyl / 1,3,6,8-tetraphenyl-4b,5,5a,9b,10,10a-hexahydro-5,10-methylbenzo[3,4]cyclobutano[1,2-b]biphenyl).

3. An ultra-microporous branched poly(arylpiperidine) based anion exchange membrane material, characterized in that, Including the introduction of tetrafunctional 1,3,7,9-tetraphenyl-4b,5,5a,9b,10,10a-hexahydro-5,10-methylbenzo[3,4]cyclobutano[1,2-b]biphenyl / 1,3,6,8-tetraphenyl-4b,5,5a,9b,10,10a-hexahydro-5,10-methylbenzo[3,4]cyclobutano[1,2-b]biphenyl as a branching agent into the polymer structural unit of polyterpenoid piperidinone, forming a branched polyarylpiperidinyl compound with a tetrabranched structure containing norbornene bisbenzocyclobutane.

4. The ultra-microporous branched poly(arylpiperidine) based anion exchange membrane material of claim 3, wherein, It has a general structural formula as shown in equation (I): Where x+y is the structural unit of the branched part, and each branched part contains two piperidine cation structures in its unit structure; the number of structural units in the linear part is n, n=n1+n2+n3+n4, where n=0.97~0.995, n1=0~0.97, n2=0~0.97, n3=0~0.97, n4=0~0.97; and x+y=0.005~0.03; And / or, the molecular weight of the ultramicroporous branched polyarylepiperidine anion exchange membrane material is 50-100 kDa; and / or, water absorption at 30°C of 29 to 38%, OH-conductivity of 70 to 85 mS cm- 1 ; and / or, water absorption at 80°C of 30 to 41 %, OH-conductivity of 135 to 150 mS cm- 1 .

5. A process for the preparation of ultra-microporous branched poly- arylpiperidine-based anion exchange membrane material, characterized by, include: The protonated ultraporous branched polyarylepiperidinyl polymer was reacted with iodomethane to obtain the ultraporous branched polyarylepiperidinyl anion exchange membrane material containing norbornene bisbenzocyclobutane structure shown in Formula 1. The structural formula of the protonated ultraporous branched polyarylepiperidinyl polymer is shown in formula (II): Where x+y is the structural unit of the branched part, and each branched part contains two piperidine cation structures in its unit structure; the number of structural units in the linear part is n, n=n1+n2+n3+n4, where n1=0~0.97, n2=0~0.97, n3=0~0.97, n4=0~0.97; and x+y=0.005~0.03, n=0.995~0.

97.

6. The production method according to claim 5, characterized by, include: The protonated hyper-porous branched polyaryl-piperidine-based polymer is dissolved in a first organic solvent, iodomethane is added for reaction, then the reaction product is precipitated in a second organic solvent, filtered and dried, then dissolved in a third organic solvent again, uniformly coated on a substrate and dried, and after ion exchange, a hyper-porous branched polyaryl-piperidine-based anion exchange membrane containing a norbornene bis-benzocyclobutane structure as shown in formula 1 is obtained. And / or, the preparation method of the protonated hyper-porous branched polyaryl-piperidine-based polymer comprises: performing superacid catalytic reaction on compound (a), compound (b) and compound (c), precipitating in methanol, filtering and drying, and the structures of compound (a), compound (b) and compound (c) are as follows:

7. The method of manufacturing according to claim 5 or 6, characterized in that: The reaction temperature is 50°C, and the reaction time is 48-72 hours; And / or, the first organic solvent is dimethyl sulfoxide; Preferably, the mass of the protonated hyper-porous branched polyaryl-piperidine-based polymer in the first organic solvent is 50-100 times; And / or, the second organic solvent is ethyl acetate; And / or, the amount of the second organic solvent is 10-20 times the volume of the first organic solvent; And / or, the third organic solvent is dimethyl sulfoxide; And / or, the amount of the third organic solvent is 30-40 times the mass of the hyper-porous branched polyaryl-piperidine-based anion exchange membrane material.

8. The method of claim 7, wherein: The preparation method of the protonated hyper-porous branched polyaryl-piperidine-based polymer comprises: dissolving compound (a), compound (b) and compound (c) in a fourth organic solvent, then adding a catalyst, and performing protonation reaction at 0°C, then precipitating the reaction product in methanol, washing and drying, and the structures of compound (a), compound (b) and compound (c) are as follows: And / or, the catalyst is trifluoroacetic acid and triflic acid; And / or, the fourth organic solvent is dichloromethane; And / or, the amount of the fourth organic solvent is 2-5 times the sum of the masses of compound (a), compound (b) and compound (c); And / or, the reaction time of the protonation reaction is 4-6 hours; And / or, the addition ratio of compound (a), compound (b) and compound (c) is 0.5-3:97-99.5:

110.

9. Use of the hyper-porous branched polyaryl-piperidine-based anion exchange membrane material according to any one of claims 3-4 in an alkaline water electrolyzer.

10. An alkaline water electrolyzer comprising an electrolyte diaphragm, wherein the electrolyte diaphragm comprises the hyper-porous branched polyaryl-piperidine-based anion exchange membrane material according to any one of claims 3-4.

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