Preparation and application of branched poly (aryl piperidine) anion exchange membrane material with high free volume

Abstract

The invention belongs to the field of high-performance anion exchange membranes for hydrogen production by electrolysis of water and preparation of the high-performance anion exchange membranes, and particularly discloses a branched poly (aryl piperidine)-based anion exchange membrane material with a high free volume as well as a preparation method and application of the branched poly (aryl piperidine)-based anion exchange membrane material. A branching agent 9, 9-diphenylfluorene is introduced into a polymer structural unit, so that the free volume in the membrane material is increased, meanwhile, the movement capacity of part of chain segments is limited, swelling of the membrane material due to water absorption is inhibited, the ionic conductivity and the dimensional stability of the membrane material are effectively improved, and the prepared anion exchange membrane can be applied to hydrogen production through water electrolysis.

Description

Technical Field

[0001] The present invention belongs to the field of high-performance anion exchange membranes for hydrogen production by water electrolysis and their preparation, and particularly relates to a preparation method and application of a branched poly (aryl piperidine)-based anion exchange membrane material with high free volume. Background Art

[0002] As human science and technology enter a stage of rapid development, human society's demand for energy is becoming increasingly strong. Especially under the advocacy of a green society, the development and utilization of clean energy (such as solar energy, wind energy, hydrogen energy, etc.) is urgent. Among them, H2 as a chemical raw material and energy storage carrier is particularly important at this stage of development. The development of hydrogen energy can achieve carbon-free participation in the production and utilization of energy, effectively protect the environment, and promote the development of a green society. The development of hydrogen energy is inseparable from the continuous improvement of anion exchange membrane electrolyzers. This type of energy storage and conversion technology requires a powerful anion exchange membrane component to support its long-term and efficient operation.

[0003] At present, anion exchange membrane water electrolysis is in the research and development stage. As one of the most important components, the ion conductivity, dimensional stability and chemical stability of anion exchange membrane are the main considerations in the development of anion exchange membrane. Due to the difference in conduction mechanism and ions conducted by proton exchange membrane, the conductivity of anion exchange membrane is far inferior to that of proton exchange membrane. However, anion exchange membrane electrolyzer mainly operates in a weakly alkaline environment, so base metals can be used to replace the precious metals in proton exchange membrane electrolyzer, greatly reducing its cost. However, anion exchange membrane operates in an alkaline environment for a long time, and its cationic groups and main chains are usually OH − The present invention provides a branched poly (aryl piperidine)-based anion exchange membrane material with high free volume. The poly (aryl piperidine)-based polymer is selected as the main chain, which can effectively improve the chemical stability of the membrane material. Then, 9,9-diphenylfluorene is introduced as a branching agent to limit the chain spacing and improve the dimensional stability of the membrane. Then, a high free volume is provided inside the polymer to improve the ion conductivity of the membrane. Summary of the invention

[0004] The present invention provides a branched poly (aryl piperidine)-based anion exchange membrane material with high free volume, which has a structure of Formula 1; in Formula 1, the structural unit of the branching part is x+y, and each unit structure of the branching part contains two piperidine cation structures, the number of structural units of the linear part is n (n=n1+n2+n3+n4), x+y=0.05~0.15, n=0.85~0.95, and the molecular weight is generally =50~80. , Formula 1 The present invention also provides a method for preparing a branched poly (aryl piperidine)-based anion exchange membrane material with a high free volume as described above, comprising: reacting a branched poly (aryl piperidine)-based polymer protonated by trifluoroacetic acid as shown in Formula 2 with iodomethane to obtain a branched poly (aryl piperidine)-based anion exchange membrane material with a high free volume as shown in Formula 1.

[0005] , Formula 2 Preferably, at room temperature, a certain amount of the branched poly(aryl piperidine)-based polymer protonated by trifluoroacetic acid as shown in Formula 2 is dissolved in an organic solvent, and then iodomethane is added. After the reaction is completed, the reactant is precipitated in the organic solvent, filtered and dried. Then, it is dissolved in an organic solvent, poured into a mold and dried, and ion exchange is performed to obtain a branched poly(aryl piperidine)-based anion exchange membrane with a high free volume as shown in Formula 1.

[0006] Preferably, the reaction temperature of the above reaction is room temperature and the reaction time is 24 to 48 h.

[0007] Preferably, the organic solvent used for the reaction is dimethyl sulfoxide, and its amount is 10 to 40 times the mass of the branched poly(arylpiperidine)-based polymer protonated by trifluoroacetic acid.

[0008] Preferably, the organic solvent used for precipitation is ethyl acetate, and its amount is 2 to 10 times the volume of the organic solvent used in the reaction.

[0009] Preferably, the organic solvent used for membrane preparation is N-methylpyrrolidone, and the amount used is 5 to 15 times the mass of the branched poly (aryl piperidine) based anion exchange membrane material.

[0010] Preferably, the branched poly (aryl piperidine)-based anion exchange membrane material with high free volume is prepared according to the following steps: the three substances shown in Formula 3 are subjected to super acid catalytic reaction, precipitated in water, filtered and dried to obtain a branched poly (aryl piperidine)-based polymer protonated by trifluoroacetic acid shown in Formula 2.

[0011] , Formula 3 The specific preparation method is as follows: dissolving a certain amount of the three substances shown in formula 3 in an organic solvent, adding trifluoroacetic acid and trifluoromethanesulfonic acid, reacting at 0°C for 4 to 12 hours, and precipitating the reactants in water to obtain a branched poly (aryl piperidine)-based polymer protonated by trifluoroacetic acid as shown in formula 2.

[0012] Further preferably, the raw materials used are as shown in Formula 3, Formula 3a is 9,9-diphenylfluorene, Formula 3b is terphenyl, Formula 3c is N-methyl-4-piperidone, and the organic solvent is dichloromethane, and its amount is 30 to 60 times that of all the substances shown in Formula 3; wherein the catalyst is trifluoroacetic acid and trifluoromethanesulfonic acid, the amount of trifluoroacetic acid is 1 to 5 of the molar amount of Formula 3c, and the amount of trifluoromethanesulfonic acid is 5 to 15 times the molar amount of Formula 3c; the reaction temperature is 0°C, the reaction time is 4 to 12h, and the drying temperature is 80°C.

[0013] Compared with the prior art, the present invention has the following beneficial effects: (1) The branched poly (aryl piperidine)-based anion exchange membrane material with high free volume provided by the present invention introduces 9,9-diphenylfluorene as a branching agent in the structure. The introduction of this type of "four-forked" branching agent can effectively limit the excessive movement of the chain segments and avoid swelling due to water absorption. The introduction of the branching agent can also construct a high free volume inside the membrane material, giving the counterions a higher free activity space. The ion conductivity of the membrane is effectively improved.

[0014] (2) The branched poly(arylpiperidine)-based polymer with high free volume provided by the present invention is prepared by Friedel-Crafts reaction and can be directly used to prepare anion exchange membrane by tape casting. The prepared anion exchange membrane has good ion conductivity, dimensional stability and chemical stability and can be used as anion exchange membrane material in alkaline water electrolyzer hydrogen production. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The synthetic route of the branched poly (aryl piperidine) based anion exchange membrane material with high free volume described in Example 2 of the present invention; Figure 2 The NMR spectra of the branched poly(arylpiperidine)-based anion exchange membrane with high free volume and the intermediate product described in Example 2 of the present invention (taking QPTPip-DPF-10 as an example); Figure 3 Graph showing the ion conductivity of the branched poly(arylpiperidine)-based anion exchange membrane material with high free volume described in Examples 1, 2, and 3 of the present invention; Figure 4 The CO2 adsorption and desorption curves of the branched poly (aryl piperidine)-based anion exchange membrane material having a high free volume described in Examples 1, 2, and 3 of the present invention are as follows; DETAILED DESCRIPTION

[0016] The present invention is further described in detail below in conjunction with embodiments: The preferred embodiments of the present invention will be described in more detail below in conjunction with specific examples.

[0017] The sources of the drugs and reagents described in the examples are as follows: 9,9-Diphenylfluorene: Shanghai Bid Pharmaceutical Technology Co., Ltd., ≥98.0% Terphenyl: Shanghai Bid Pharmaceutical Technology Co., Ltd., ≥99.9% N -Methyl-4-piperidone: Shanghai Bid Pharmaceutical Technology Co., Ltd., ≥99.0% N -Methylpyrrolidone: Aladdin Biochemical Technology Co., Ltd., ≥99.5% Dimethyl sulfoxide: Shanghai Lingfeng Chemical Reagent Co., Ltd., ≥99.0% Ethyl acetate: Shanghai Lingfeng Chemical Reagent Co., Ltd., ≥99.0% Potassium carbonate: Shanghai Lingfeng Chemical Reagent Co., Ltd., ≥99.0% Sodium hydroxide: Shanghai Lingfeng Chemical Reagent Co., Ltd., ≥99.0% Dichloromethane: Shanghai Lingfeng Chemical Reagent Co., Ltd., ≥99.0% Trifluoroacetic acid: Shanghai Titan Technology Co., Ltd., ≥99.0% Trifluoromethanesulfonic acid: Shanghai Titan Technology Co., Ltd., ≥99.0% Iodomethane: Shanghai Myril Biochemical Technology Co., Ltd., ≥99.0% Example

[0018] A method for preparing a branched poly (aryl piperidine)-based anion exchange membrane material with high free volume comprises the following steps: (1) Preparation of branched poly(arylpiperidine)-based polymers protonated with trifluoroacetic acid 9,9-diphenylfluorene (0.3184 g, 1.0 mmol), terphenyl (4.3759 g, 19.0 mmol), N -Methyl-4-piperidone (2.6140 g, 23.1 mmol) was added to a two-necked flask with mechanical stirring, and an ice bath covered more than half of the flask volume. Then 24 mL of dichloromethane and 2 mL of trifluoroacetic acid were added and stirred evenly. Then 20 mL of trifluoromethanesulfonic acid was added and the reaction was continued at 0°C for 8 hours. The highly viscous solution was poured into deionized water for precipitation, and then the product was cut into pieces and washed with multiple changes of water until the pH was neutral. Finally, it was dried in a vacuum oven at 80°C for 24 hours to obtain a white block solid (PTPip-DPF-5) with a yield of 93.5%.

[0019] (2) Preparation of branched poly(arylpiperidine)-based anion exchange membrane PTPip-DPF-5 (7.3623 g, 20 mmol) was added to a round-bottom flask and dissolved in 200 mL DMSO, followed by the addition of potassium carbonate (5.5284 g, 40 mmol) and CH3I (140 mmol, 19.8716 g). The mixed solution was stirred mechanically and reacted at room temperature in the dark for 24 hours. The resulting solution was poured into 500 mL ethyl acetate for precipitation. It was then filtered and dried in a vacuum oven at 80 °C for 24 hours to obtain a white powder (QPTPip-DPF-5) with a yield of 86.7%.

[0020] The synthetic route of the above preparation method is as follows Figure 1 shown. Example

[0021] A method for preparing a branched poly (aryl piperidine)-based anion exchange membrane material with high free volume, comprising the following steps (1) Preparation of branched poly(arylpiperidine)-based polymers protonated with trifluoroacetic acid 9,9-diphenylfluorene (0.6368 g, 2.0 mmol), terphenyl (4.1456 g, 18.0 mmol), N -Methyl-4-piperidone (2.7385 g, 24.2 mmol) was added to a two-necked flask with mechanical stirring, and an ice bath covered more than half of the flask volume. Then 25 mL of dichloromethane and 2 mL of trifluoroacetic acid were added and stirred evenly. Then 21 mL of trifluoromethanesulfonic acid was added and the reaction was continued at 0°C for 6 hours. The highly viscous solution was poured into deionized water for precipitation, and then the product was cut into pieces and washed with multiple changes of water until the pH was neutral. Finally, it was dried in a vacuum oven at 80°C for 24 hours to obtain a white block solid (PTPip-DPF-10) with a yield of 94.7%.

[0022] (2) Preparation of branched poly(arylpiperidine)-based anion exchange membrane PTPip-DPF-5 (7.5806 g, 20 mmol) was added to a round-bottom flask and dissolved in 200 mL DMSO, followed by the addition of potassium carbonate (5.5284 g, 40 mmol) and CH3I (140 mmol, 19.8716 g). The mixed solution was stirred mechanically and reacted at room temperature in the dark for 24 hours. The resulting solution was poured into 500 mL ethyl acetate for precipitation. It was then filtered and dried in a vacuum oven at 80 °C for 24 hours to obtain a white powder (QPTPip-DPF-10) with a yield of 85.3%. 1 H NMR (DMSO-d6) as attached Figure 2 shown. Example

[0023] A method for preparing a branched poly (aryl piperidine)-based anion exchange membrane material with high free volume comprises the following steps: (1) Preparation of branched poly(arylpiperidine)-based polymers protonated with trifluoroacetic acid 9,9-diphenylfluorene (0.9552 g, 3.0 mmol), terphenyl (4.3759 g, 17.0 mmol), N -Methyl-4-piperidone (2.8629 g, 25.3 mmol) was added to a two-necked flask with mechanical stirring, and an ice bath covered more than half of the flask volume. Then 27 mL of dichloromethane and 2 mL of trifluoroacetic acid were added and stirred evenly. Then 22 mL of trifluoromethanesulfonic acid was added and the reaction was continued at 0°C for 5 hours. The highly viscous solution was poured into deionized water for precipitation, and then the product was cut into pieces and washed with multiple changes of water until the pH was neutral. Finally, it was dried in a vacuum oven at 80°C for 24 hours to obtain a white block solid (PTPip-DPF-15) with a yield of 95.1%.

[0024] (2) Preparation of branched poly(arylpiperidine)-based anion exchange membrane PTPip-DPF-5 (7.7959 g, 20 mmol) was added to a round-bottom flask and dissolved in 200 mL DMSO, followed by the addition of potassium carbonate (5.5284 g, 40 mmol) and CH3I (140 mmol, 19.8716 g). The mixed solution was stirred mechanically and reacted at room temperature in the dark for 24 hours. The resulting solution was poured into 500 mL ethyl acetate for precipitation. It was then filtered and dried in a vacuum oven at 80 °C for 24 hours to obtain a white powder (QPTPip-DPF-15) with a yield of 84.9%.

Claims

1. A branched poly (aryl piperidine) based anion exchange membrane material with high free volume, characterized in that: The structural formula is: , formula 1; In Formula 1, the structural unit of the branching part is x+y, and each unit structure of the branching part contains two piperidinium cation structures, and the number of structural units of the linear part is n (n=n1+n2+n3+n4), x+y=0.05~0.15, n=0.85~0.

95.

2. The method for preparing a branched poly (aryl piperidine)-based anion exchange membrane material with high free volume according to claim 1, characterized in that: The method comprises the following steps: reacting a branched poly(aryl piperidine)-based polymer protonated by trifluoroacetic acid as shown in formula 2 with methyl iodide, dissolving the obtained product in an organic solvent and forming a membrane, and then performing ion exchange to obtain a branched poly(aryl piperidine)-based anion exchange membrane with a high free volume as shown in formula 1; , formula 2.

3. The method for preparing a branched poly (aryl piperidine) based anion exchange membrane material with high free volume according to claim 2, characterized in that: The method also includes the following steps: at room temperature, firstly, pouring the branched poly (aryl piperidine) based polymer protonated by trifluoroacetic acid into a reaction container and dissolving it with an organic solvent, then adding iodomethane and potassium carbonate into the reaction container and stirring to react, and after the reaction is completed, settling in an organic solvent, filtering and drying, and then dissolving the product in an organic solvent, pouring it into a mold and drying it to form a film, and then immersing it in a sodium hydroxide solution, so as to obtain a branched poly (aryl piperidine) based anion exchange membrane with a high free volume as shown in Formula 1.

4. The method for preparing a branched poly(arylpiperidine)-based anion exchange membrane material with high free volume according to claim 3, characterized in that: The organic solvent used for the reaction is dimethyl sulfoxide, the organic solvent used for precipitation is ethyl acetate, and the organic solvent used for film preparation is N-methylpyrrolidone. The drying temperature is 80°C, the reaction temperature is room temperature, the reaction time is 24 to 48 h, the reaction conditions are to avoid light, the immersion solution is 1 M NaOH solution, and the immersion time is 12 to 48 h.

5. The method for preparing a branched poly (aryl piperidine) based anion exchange membrane material with high free volume according to claim 2, characterized in that: The method for preparing the branched poly(aryl piperidine)-based polymer protonated by trifluoroacetic acid comprises the following steps: continuing polymerization reaction of the three substances shown in Formula 3 under super acid catalysis to obtain the branched poly(aryl piperidine)-based polymer protonated by trifluoroacetic acid shown in Formula 2; , Formula 3.

6. The method for preparing a branched poly (aryl piperidine) based anion exchange membrane material with high free volume according to claim 5, characterized in that: The preparation method of a branched poly (aryl piperidine) based polymer protonated by trifluoroacetic acid comprises the following steps: dissolving the three substances described in formula 3 in an organic solvent, adding catalysts in succession, pouring into water for sedimentation after the reaction is completed, filtering and drying, and obtaining a branched poly (aryl piperidine) based polymer protonated by trifluoroacetic acid as shown in formula 2.

7. The method for preparing a branched poly (aryl piperidine) based anion exchange membrane material with high free volume according to claim 6, characterized in that: The raw materials used in the preparation of the branched poly (aryl piperidine)-based polymer protonated by trifluoroacetic acid are shown in Formula 3, where Formula 3a is 9,9-diphenylfluorene, Formula 3b is terphenyl, Formula 3c is N-methyl-4-piperidone, and the organic solvent is dichloromethane, and its amount is 30 to 60 times that of all the substances shown in Formula 3; wherein the catalysts are trifluoroacetic acid and trifluoromethanesulfonic acid, the amount of trifluoroacetic acid is 1 to 5 of the molar amount of Formula 3c, and the amount of trifluoromethanesulfonic acid is 5 to 15 times the molar amount of Formula 3c; the reaction temperature is 0°C, the reaction time is 4 to 12 hours, and the drying temperature is 80°C, so that the branched poly (aryl piperidine)-based polymer protonated by trifluoroacetic acid can be obtained.

8. The use of the branched poly (aryl piperidine) based anion exchange membrane material with high free volume according to claim 1, characterized in that: Used in alkaline water electrolyzers to produce hydrogen.

Images