CN114471179B - A kind of main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane and its preparation method - Google Patents

Abstract

The invention discloses an alkali-resistant bipolar membrane with a main chain fluorocarbon-phthalocyanine catalytic layer and a preparation method thereof, belonging to the field of electric drive membranes.

Description

A kind of main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane and its preparation method

Technical field

The invention relates to a main chain fluorocarbon-phthalocyanine catalytic layer acid-base bipolar membrane and a preparation method thereof, and belongs to the technical field of electric drive membranes.

Background technique

Bipolar membrane is a composite membrane material composed of an anion exchange membrane layer, a cation exchange membrane layer and an intermediate interface layer (intermediate layer). Under the action of an electric field, water molecules in the middle layer of the bipolar membrane undergo water dissociation to generate hydrogen ions and hydroxyl radicals, thereby achieving the purpose of generating acid and alkali. The theoretical potential of bipolar membrane water dissociation to produce acid and alkali is 0.828V, and the theoretical potential of electrolysis of water to produce acid and alkali is 2.057V. In addition, the water dissociation speed in the middle layer of the bipolar membrane is about 50 million times faster than the normal water dissociation speed. Therefore, bipolar membrane technology has the characteristics of low energy consumption, high efficiency, and pollution-free products, and has been widely used in various fields such as acid and alkali production and recycling, marine chemical industry, pollution control, and organic synthesis.

Aromatic carbon skeletons such as polyaryl ether ketone are currently commonly used bipolar membrane base membrane materials, and quaternary ammonium functional groups are common functional groups in the anion exchange membrane layer of bipolar membranes. However, the carbon-oxygen bonds in the aromatic carbon skeleton are easily attacked and degraded by hydroxyl radicals. In addition, due to the attack of hydroxyl radicals, the quaternary ammonium functional group is destroyed due to the occurrence of Hoffman reaction, affinity substitution reaction, etc., resulting in a generally low alkali resistance concentration of the bipolar membrane. On the other hand, the existing bipolar membrane is composed of an anion exchange membrane layer, a cation exchange membrane layer and an intermediate layer. Due to the differences in physical and chemical properties between different layers, it is easy to peel off during use, thereby reducing the risk of improves the service life of the bipolar membrane.

Contents of the invention

In order to solve the above-mentioned problems existing in the prior art, the present invention provides a main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane and a preparation method thereof. The anion exchange membrane layer and the cation exchange membrane layer in the bipolar membrane are both Using perfluorocarbon as the main chain overcomes the common shortcomings of carbon-oxygen bonds in the main chain being easily attacked and degraded by hydroxyl radicals, and the anion and cation exchange membrane layers have similar physical and chemical properties, thus reducing the risk of peeling off during use. possibility, extending its service life.

The technical solution of the present invention is as follows:

One of the objects of the present invention is to provide a main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane, which includes a cation exchange membrane layer and an anion exchange membrane layer. Both the cation exchange membrane layer and the anion exchange membrane layer are made of perfluorocarbon. As the main chain, the nitrogen heterocycle serves as the cationic functional group on the anion exchange membrane layer; among them, the chemical structural formula of the cation exchange membrane layer is:

The chemical structural formula of the anion exchange membrane layer is:

Among them, x is the degree of polymerization of the main chain of the polymer containing chlorotrifluoroethylene structural units, n is the degree of polymerization of the side chain containing the sulfonic acid group substituent, m is the degree of polymerization of the side chain containing the imidazole substituent, n and m are not an integer that is zero.

The object of the present invention is also to provide a method for preparing a main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane, which specifically includes the following steps:

S1. Preparation of cation exchange membrane liquid: Dissolve the polymer containing chlorotrifluoroethylene structural units in organic solvent I, pass nitrogen to remove oxygen, and after heating, dissolve the polymer in a molar ratio of 1:(20~100):1:2. Polymers containing chlorotrifluoroethylene structural units, sodium styrene sulfonate, CuBr and bipyridine are added to the reaction system, and under nitrogen protection, a constant temperature sulfonation reaction is carried out at 90 to 130°C for 16 to 48 hours, and the reaction solution is Put it into a dialysis bag and dialyze in water for 24 hours; dry the solution in the dialysis bag to prepare polychlorotrifluoroethylene grafted sodium styrene sulfonate side chain copolymer (PCTEF-g-PSSNa);

S2. Preparation of anion exchange membrane liquid: Dissolve the polymer containing chlorotrifluoroethylene structural units in organic solvent II, purge nitrogen to remove oxygen, and after heating, follow the steps of polymer containing chlorotrifluoroethylene structural units, imidazole-containing monomers Mix the monomer, uBr and bipyridine at a molar ratio of 1:(20~100):1:2, react under nitrogen protection at a constant temperature for 16~48 hours, put the reaction solution into a dialysis bag, and dialyze in water for 24 hours; dry for dialysis The solution in the bag is used to prepare polychlorotrifluoroethylene-grafted vinylimidazole side chain copolymer (PCTEF-g-PVIm);

S3. Preparation of phthalocyanine precursor: KH-560 and aminophthalocyanine are added into the reaction bottle at a molar ratio of 1:1, add organic solvent III, stir evenly, and react at room temperature for 1 to 3 hours to obtain the phthalocyanine-KH560 precursor;

S4. Preparation of the water dissociation catalyst for the intermediate layer of the bipolar membrane: Add the phthalocyanine-KH560 precursor obtained through step S3 and the silane coupling agent into the reactor. At the same time, add the acidic catalyst and distilled water to adjust the pH of the reaction system to 2.5~ 3.5, react at 50-60°C for 1-8 hours to obtain KH-560 modified phthalocyanine silica sol as a bipolar membrane intermediate layer water dissociation catalyst;

S5. Preparation of bipolar membrane: Cast the polychlorotrifluoroethylene-grafted sodium styrene sulfonate side chain copolymer solution prepared in step S1 on a clean glass plate, and dry it to prepare a cation exchange membrane layer. Spray KH-560 modified phthalocyanine silica sol on the cation exchange membrane layer. After drying, cast the polychlorotrifluoroethylene-grafted vinylimidazole side chain copolymer obtained in step S2 on the cation exchange membrane layer and dry it. Finally, a chain fluorocarbon-phthalocyanine catalytic layer is obtained as an alkali-resistant bipolar membrane.

Further, the polymers containing chlorotrifluoroethylene structural units in steps S1 and S2 are poly(vinylidene fluoride-chlorotrifluoroethylene), poly(vinylidene fluoride-chlorotrifluoroethylene-tetrafluoroethylene), poly(vinylidene fluoride-chlorotrifluoroethylene-tetrafluoroethylene), (tetrafluoroethylene-chlorotrifluoroethylene) or polychlorotrifluoroethylene.

Further, the organic solvent I in step S1 is any one or two of N,N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, and N,N-dimethylformamide. Combinations in any proportion.

Further, the imidazole group-containing monomer in step S2 is 2-methyl-1-vinylimidazole, 2,4-dimethyl-1-vinylimidazole, and 2,4,5-trimethyl-1 -Vinylimidazole, 5-ethyl-2,4-dimethyl-1-vinylimidazole, 2-ethyl-4,5-dimethyl-1-vinylimidazole, 4-ethyl-2, 5-Dimethyl-1-vinylimidazole, 2-propyl-4,5-dimethyl-1-vinylimidazole, 4-propyl-2,5-dimethyl-1-vinylimidazole, 2-Butyl-4,5-dimethyl-1-vinylimidazole, 4-butyl-2,5-dimethyl-1-vinylimidazole, 2,4-diethyl-5-methyl -1-vinylimidazole, 4,5-diethyl-2-methyl-1-vinylimidazole, 2,4-dibutyl-5-methyl-1-vinylimidazole, 4,5-bis Any one of butyl-2-methyl-1-vinylimidazole.

Further, the organic solvent II in step S2 is any one of tetrahydrofuran, N,N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, N,N-dimethylformamide or A combination of two types in any proportion.

Further, the organic solvent III in step S3 is any one of anhydrous methanol, anhydrous ethanol, isopropyl alcohol, tetrahydrofuran, and acetone or a combination of two in any proportion.

Further, in step S3, the amino phthalocyanine is a transition metal-containing amino phthalocyanine, and the transition metal is any one of Fe, Mg, Ba, Sc, Ti, V, Cr, Mn, Co, Ni, Cu or Zn .

Further, in step S4, the silane coupling agent is any one of KH540, KH550, KH602 or KH792; the catalyst is any one of hydrochloric acid, formic acid or acetic acid.

Further, in step S5, any one of the aerosol spraying method, electrostatic spraying, dipping-pulling method or spin coating method is used to spray KH-560 modified phthalocyanine silica sol on the cation exchange membrane layer.

Compared with the existing technology, the beneficial effects of the present invention are:

(1) The main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane provided by the present invention, in which the cation exchange membrane layer and the anion exchange membrane layer both use fluorocarbon as the main chain, can overcome the aromatic problems in the prior art. The carbon-oxygen bond in the carbon skeleton is easily attacked and degraded by hydroxyl radicals. At the same time, the nitrogen heterocycle is used as the cationic functional group of the anion exchange membrane layer to replace the quaternary ammonium salt functional group. On the one hand, it can avoid the occurrence of Hoffmann reaction and affinity. and substitution reaction to destroy the quaternary ammonium salt functional group. On the other hand, the electron distribution of the nitrogen heterocyclic functional group is more uniform and has stronger alkali resistance, which can improve the alkali resistance of the bipolar membrane, thereby reducing the electrodialysis generated during electrodialysis. The acid-base concentration is increased.

(2) In the main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane provided by the present invention, both the anion exchange membrane layer and the cation exchange membrane layer have fluorocarbon chains as the main chain, and the anion and cation exchange membrane layers have similar physical and chemical properties. properties, avoiding differences in physical and chemical properties between different layers, thereby reducing the possibility of peeling during use and extending its service life.

Detailed ways

The present invention will be further described below in conjunction with preferred embodiments. The endpoints and any values of the ranges disclosed in the present invention are not limited to the precise ranges or values. These ranges or values should be understood to include those close to these ranges or values. Value; for numerical ranges, the endpoint values of each range, the endpoint values of each range and individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges. These numerical ranges should be deemed to be specifically disclosed herein.

The materials, reagents, etc. used in the following examples can all be obtained from commercial sources unless otherwise specified;

The experimental methods in the following examples are all conventional methods unless otherwise specified.

Example 1

An alkali-resistant bipolar membrane with a main chain fluorocarbon-phthalocyanine catalytic layer, including a cation exchange membrane layer and an anion exchange membrane layer. Both the cation exchange membrane layer and the anion exchange membrane layer have perfluorocarbon as the main chain, and nitrogen heterocycles as Cationic functional groups on the anion exchange membrane layer; among them, the chemical structural formula of the cation exchange membrane layer is:

The chemical structural formula of the anion exchange membrane layer is:

Among them, x is the degree of polymerization of the main chain of the polymer containing chlorotrifluoroethylene structural units, n is the degree of polymerization of the side chain containing the sulfonic acid group substituent, m is the degree of polymerization of the side chain containing the imidazole substituent, n and m are not an integer that is zero.

Example 2

A method for preparing a main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane, including the following steps:

S1. Preparation of cation exchange membrane liquid: Weigh 10g of poly(vinylidene fluoride-chlorotrifluoroethylene (the copolymer contains 25% chlorotrifluoroethylene)) and dissolve it in 120 mL of N-methylpyrrolidone, pass nitrogen to remove oxygen, and heat to After reaching 120°C, add 126.3g sodium styrene sulfonate, 4.36g CuBr and 4.76g bipyridine. Under nitrogen protection, perform a constant temperature sulfonation reaction at 120°C for 24 hours. Pour the reaction solution into an alcohol/water mixed solvent (V /V=1:1), precipitate the graft polymer, put it into a dialysis bag, and dialyze in water for 24 hours to remove copper ions, bromide ions, bipyridyl and unreacted monomers; collect the solution in the dialysis bag, Concentrate and dry to prepare polychlorotrifluoroethylene grafted sodium styrene sulfonate side chain copolymer (PCTEF-g-PSSNa); wherein, the grafting reaction is as follows:

S2. Preparation of anion exchange membrane liquid: Weigh 10g of poly(vinylidene fluoride-chlorotrifluoroethylene) (the copolymer contains 25% chlorotrifluoroethylene) and dissolve it in 120 mL of N,N-dimethylformamide, and purge with nitrogen. Remove oxygen, raise the temperature to 80°C, add 74.44g 2-methyl-1-vinylimidazole, 4.36g CuBr and 10.56g pentamethyldiethyltriamine, react at a constant temperature for 48 hours under nitrogen protection, and put the reaction solution into In the dialysis bag, dialyze in water for 24 hours to remove copper ions, bromide ions, bipyridyl and unreacted monomers; collect the solution in the dialysis bag, concentrate, and dry to prepare polychlorotrifluoroethylene-grafted vinylimidazole side chains. Copolymer (PCTEF-g-PVIm); wherein, the grafting reaction is as follows:

S3. Preparation of phthalocyanine precursor: Weigh 2.36g KH-560 and 5.77g copper phthalocyanine into the reaction bottle, add 35 mL of absolute ethanol, stir evenly, react at room temperature for 3 hours, and distill away the solvent to obtain iron phthalocyanine-KH560 precursor. ;

S4. Preparation of bipolar membrane intermediate layer water dissociation catalyst: Weigh 8.06g of the iron phthalocyanine-KH560 precursor obtained in step S3 and add 1.11g of silane coupling agent KH792 into the reactor. At the same time, add 18mL of ethanol and 7.5mL of ethanol. Distilled water and 0.6 mL of 1.0% hydrochloric acid were used to adjust the pH of the reaction system to 3.5. The reaction was carried out at 50°C for 1 hour to obtain KH-560 modified iron phthalocyanine silica sol as a bipolar membrane intermediate layer water dissociation catalyst. The reaction was as follows: Show:

S5. Preparation of bipolar membrane: Cast the polychlorotrifluoroethylene-grafted sodium styrene sulfonate side chain copolymer solution prepared in step S1 on a clean glass plate, and dry it to prepare a cation exchange membrane layer. Spray KH-560 modified iron phthalocyanine silica sol on the cation exchange membrane layer using electrostatic spraying. After drying, the polychlorotrifluoroethylene grafted vinyl imidazole side chain copolymer obtained in step S2 is cast on the cation exchange membrane. After drying, the negative side was soaked in methyl iodide and tetrahydrofuran solution for 5 hours, then taken out, and the impurities on the membrane surface were washed with distilled water to obtain a chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane.

Example 3

A method for preparing a main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane, including the following steps:

S1. Preparation of cation exchange membrane liquid: Weigh 10g of poly(vinylidene fluoride-chlorotrifluoroethylene-tetrafluoroethylene) (the copolymer contains 25% chlorotrifluoroethylene) and dissolve it in 120 mL of dimethyl sulfoxide. Oxygen, after raising the temperature to 80°C, add 151.6g sodium styrene sulfonate, 4.36g CuBr and 10.56g pentamethyldiethyltriamine, and perform a constant temperature sulfonation reaction at 80°C for 48 hours under nitrogen protection. The solution is poured into ethanol, and the graft polymer is precipitated, which is then put into a dialysis bag and dialyzed in water for 24 hours to remove copper ions, bromide ions, bipyridyl and unreacted monomers; the solution in the dialysis bag is collected, concentrated, and dried. Dry to prepare polychlorotrifluoroethylene grafted sodium styrene sulfonate side chain copolymer (PCTEF-g-PSSNa); wherein, the grafting reaction is as shown in Example 1:

S2. Preparation of anion exchange membrane liquid: Weigh 10g of poly(vinylidene fluoride-chlorotrifluoroethylene-tetrafluoroethylene) (the copolymer contains 25% chlorotrifluoroethylene) and dissolve it in 120 mL of tetrahydrofuran, pass nitrogen to remove oxygen, and raise the temperature. After reaching 80°C, add 74.4g 5-ethyl-2,4-dimethyl-1-vinylimidazole, 4.36g CuBr and 4.76g bipyridine, react at a constant temperature for 16 hours under nitrogen protection, and put the reaction solution into a dialysis bag. In, dialyze in water for 24 hours to remove copper ions, bromide ions, bipyridyl and unreacted monomers; collect the solution in the dialysis bag, concentrate, and dry to prepare polychlorotrifluoroethylene grafted vinyl imidazole side chain copolymer. (PCTEF-g-PVIm); where, the grafting reaction is as follows:

S3. Preparation of phthalocyanine precursor: Weigh 2.36g KH-560 and 5.70g copper phthalocyanine into the reaction bottle, add 30 mL acetone and stir evenly, react at room temperature for 1 hour, distill the solvent away to obtain the copper phthalocyanine-KH560 precursor;

S4. Preparation of bipolar membrane intermediate layer water dissociation catalyst: Weigh 8.13g of copper phthalocyanine-KH560 precursor obtained in step S3 and add 1.11g of silane coupling agent KH602 into the reactor. At the same time, add 18mL of ethanol and 7.5mL of ethanol. Distilled water and 0.6 mL formic acid, adjust the pH of the reaction system to 2.5, react at 50°C for 2 hours, and obtain KH-560 modified copper phthalocyanine silica sol as a bipolar membrane intermediate layer water dissociation catalyst; the reaction is as follows:

S5. Preparation of bipolar membrane: Cast the polychlorotrifluoroethylene-grafted sodium styrene sulfonate side chain copolymer solution prepared in step S1 on a clean glass plate, and dry it to prepare a cation exchange membrane layer. Spray KH-560 modified copper phthalocyanine silica sol on the cation exchange membrane layer by spin coating. After drying, the polychlorotrifluoroethylene grafted vinyl imidazole side chain copolymer obtained in step S2 is cast on the cation exchange membrane. After drying, the negative side was soaked in methyl iodide and tetrahydrofuran solution for 5 hours, then taken out, and the impurities on the membrane surface were washed with distilled water to obtain a chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane.

Example 4

A method for preparing a main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane, including the following steps:

S1. Preparation of cation exchange membrane liquid: Weigh 10g of poly(tetrafluoroethylene-chlorotrifluoroethylene) (the copolymer contains 25% chlorotrifluoroethylene), dissolve it in 120 mL of N,N-dimethylacetamide, and ventilate with nitrogen. Remove oxygen, raise the temperature to 130°C, add 126.3 sodium styrene sulfonate, 4.36g CuBr and 10.56g pentamethyldiethyltriamine, and perform a constant temperature sulfonation reaction at 80°C for 16 hours under nitrogen protection. In the dialysis bag, dialyze in water for 24 hours to remove copper ions, bromide ions, bipyridyl and unreacted monomers; collect the solution in the dialysis bag, concentrate, and dry to prepare polychlorotrifluoroethylene grafted styrene sulfonic acid. Sodium side chain copolymer (PCTEF-g-PSSNa); wherein, the grafting reaction is as shown in Example 1:

S2. Preparation of anion exchange membrane liquid: Weigh 10g of poly(tetrafluoroethylene-chlorotrifluoroethylene) (the copolymer contains 25% chlorotrifluoroethylene) and dissolve it in 120 mL of N-methylpyrrolidone, purge nitrogen to remove oxygen, and raise the temperature. After reaching 85°C, add 70.4g 2,4-dimethyl-1-vinylimidazole, 4.36g CuBr and 4.76g bipyridine, react at a constant temperature for 18 hours under nitrogen protection, put the reaction solution into a dialysis bag, and dialyze in water 24h, remove copper ions, bromide ions, bipyridyl and unreacted monomers; collect the solution in the dialysis bag, concentrate and dry to prepare polychlorotrifluoroethylene grafted vinyl imidazole side chain copolymer (PCTEF-g- PVIm); where, the grafting reaction is as follows:

S3. Preparation of phthalocyanine precursor: Weigh 2.36g KH-560 and 5.73g cobalt phthalocyanine into the reaction bottle, add 35 mL tetrahydrofuran and stir evenly, react at room temperature for 2 hours, distill the solvent away to obtain the cobalt phthalocyanine-KH560 precursor;

S4. Preparation of bipolar membrane intermediate layer water dissociation catalyst: Weigh 8.09g of cobalt phthalocyanine-KH560 precursor obtained in step S3 and add 1.11g of silane coupling agent KH540 into the reactor. At the same time, add 18mL of ethanol and 7.5mL of ethanol. Distilled water and 0.6 mL acetic acid, adjust the pH of the reaction system to 3.0, react at 50°C for 3 hours, and obtain KH-560 modified cobalt phthalocyanine silica sol as a bipolar membrane intermediate layer water dissociation catalyst; the reaction is as follows:

S5. Preparation of bipolar membrane: Cast the polychlorotrifluoroethylene-grafted sodium styrene sulfonate side chain copolymer solution prepared in step S1 on a clean glass plate, and dry it to prepare a cation exchange membrane layer. Spray KH-560 modified cobalt phthalocyanine silica sol on the cation exchange membrane layer using the dipping and pulling method. After drying, cast the polychlorotrifluoroethylene-grafted vinylimidazole side chain copolymer obtained in step S2 onto the cation exchange membrane layer. On the exchange membrane layer, after drying, the negative side was soaked in methyl iodide and tetrahydrofuran solution for 5 hours, then taken out, and the impurities on the membrane surface were washed with distilled water to obtain a chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane.

Example 5

A method for preparing a main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane, including the following steps:

S1. Preparation of cation exchange membrane liquid: Weigh 10g of polychlorotrifluoroethylene (the copolymer contains 25% chlorotrifluoroethylene) and dissolve it in 120 mL of N,N-dimethylformamide, pass nitrogen to remove oxygen, and raise the temperature to 110 After adding 140.0 sodium styrene sulfonate, 4.36g CuBr and 10.76g pentamethyldiethyltriamine, perform a constant temperature sulfonation reaction at 110°C for 40 hours under nitrogen protection, put the reaction solution into a dialysis bag, and Dialyze against water for 24 hours to remove copper ions, bromide ions, bipyridyl and unreacted monomers; collect the solution in the dialysis bag, concentrate, and dry to prepare polychlorotrifluoroethylene grafted sodium styrene sulfonate side chain copolymer ( PCTEF-g-PSSNa); wherein, the grafting reaction is as shown in Example 1:

S2. Preparation of anion exchange membrane liquid: Weigh 10g polychlorotrifluoroethylene (the copolymer contains 25% chlorotrifluoroethylene) and dissolve it in 120 mL N,N-dimethylacetamide, purge nitrogen to remove oxygen, and raise the temperature to 80 89.68g 2-ethyl-4,5-dimethyl-1-vinylimidazole, 4.36g CuBr and 10.56g pentamethyldiethyltriamine were added at ℃, and the reaction was carried out at a constant temperature for 24 hours under nitrogen protection. Put it into a dialysis bag and dialyze it in water for 24 hours to remove copper ions, bromide ions, bipyridyl and unreacted monomers; collect the solution in the dialysis bag, concentrate and dry it to prepare polychlorotrifluoroethylene grafted vinyl imidazole Side chain copolymer (PCTEF-g-PVIm); where the grafting reaction is as follows:

S3. Preparation of phthalocyanine precursor: Weigh 2.36g KH-560 and 5.70g cobalt phthalocyanine into the reaction bottle, add 35 mL isopropyl alcohol, stir evenly, react at room temperature for 3 hours, and distill away the solvent to obtain cobalt phthalocyanine-KH560 precursor. ;

S4. Preparation of bipolar membrane intermediate layer water dissociation catalyst: Weigh 8.09g of cobalt phthalocyanine-KH560 precursor obtained in step S3 and add 1.11g of silane coupling agent KH550 into the reactor. At the same time, add 18mL of ethanol and 7.5mL of ethanol. Distilled water and 0.6 mL 1.0% hydrochloric acid, adjust the pH of the reaction system to 3.0, react at 50°C for 1 hour, and obtain KH-560 modified cobalt phthalocyanine silica sol as a bipolar membrane intermediate layer water dissociation catalyst; where, the reaction is as follows Show:

S5. Preparation of bipolar membrane: Cast the polychlorotrifluoroethylene-grafted sodium styrene sulfonate side chain copolymer solution prepared in step S1 on a clean glass plate, and dry it to prepare a cation exchange membrane layer. Spray KH-560 modified cobalt phthalocyanine silica sol on the cation exchange membrane layer using the aerosol spraying method. After drying, the polychlorotrifluoroethylene grafted vinyl imidazole side chain copolymer obtained in step S2 is cast on the cation exchange membrane layer. On the membrane layer, after drying, the negative side was soaked in methyl iodide and tetrahydrofuran solution for 5 hours, then taken out, and the impurities on the membrane surface were washed with distilled water to obtain a chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane.

Example 6

A method for preparing a main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane, including the following steps:

S1. Preparation of cation exchange membrane liquid: Weigh 10g of poly(vinylidene fluoride-chlorotrifluoroethylene) (the copolymer contains 25% chlorotrifluoroethylene) and dissolve it in 120 mL of N-methylpyrrolidone, purge nitrogen to remove oxygen, and raise the temperature. After reaching 130°C, add 126.3 sodium styrene sulfonate, 4.36g CuBr and 4.76g bipyridine. Under nitrogen protection, perform a constant temperature sulfonation reaction at 130°C for 20 hours. Pour the reaction solution into ethanol and precipitate to obtain graft. Put the polymer and precipitate into a dialysis bag and dialyze in water for 24 hours to remove copper ions, bromide ions, bipyridyl and unreacted monomers; collect the solution in the dialysis bag, concentrate, and dry to prepare polychlorotrifluoroethylene. Grafting sodium styrene sulfonate side chain copolymer (PCTEF-g-PSSNa); wherein, the grafting reaction is as shown in Example 1:

S2. Preparation of anion exchange membrane liquid: Weigh 10g of poly(vinylidene fluoride-chlorotrifluoroethylene) (the copolymer contains 25% chlorotrifluoroethylene) and dissolve it in 120 mL of dimethyl sulfoxide, pass nitrogen to remove oxygen, and heat to After 80°C, add 89.68g 5-ethyl-2,4-dimethyl-1-vinylimidazole, 4.36g CuBr and 10.56g pentamethyldiethyltriamine, and react at a constant temperature for 18 hours under nitrogen protection. The solution is put into a dialysis bag and dialyzed in water for 24 hours to remove copper ions, bromide ions, bipyridyl and unreacted monomers; the solution in the dialysis bag is collected, concentrated and dried to prepare polychlorotrifluoroethylene grafted vinyl. Imidazole side chain copolymer (PCTEF-g-PVIm); where, the grafting reaction is as follows:

S3. Preparation of phthalocyanine precursor: Weigh 2.36g KH-560 and 5.70g iron phthalocyanine into the reaction bottle, add 30 mL anhydrous methanol, stir evenly, react at room temperature for 2 hours, and distill away the solvent to obtain iron phthalocyanine-KH560 precursor. ;

S4. Preparation of bipolar membrane intermediate layer water dissociation catalyst: Weigh 8.06g of the iron phthalocyanine-KH560 precursor obtained in step S3 and add 0.90g of silane coupling agent KH540 into the reactor. At the same time, add 18mL of ethanol and 7.5mL of ethanol. Distilled water and 0.6 mL 1.0% hydrochloric acid, adjust the pH of the reaction system to 3.5, react at 50°C for 1 hour, and obtain KH-560 modified iron phthalocyanine silica sol as a bipolar membrane intermediate layer water dissociation catalyst; where, the reaction is as follows Show:

S5. Preparation of bipolar membrane: Cast the polychlorotrifluoroethylene-grafted sodium styrene sulfonate side chain copolymer solution prepared in step S1 on a clean glass plate, and dry it to prepare a cation exchange membrane layer. Spray KH-560 modified cobalt phthalocyanine silica sol on the cation exchange membrane layer using electrostatic spraying. After drying, the polychlorotrifluoroethylene grafted vinyl imidazole side chain copolymer obtained in step S2 is cast on the cation exchange membrane. After drying, the negative side was soaked in methyl iodide and tetrahydrofuran solution for 5 hours, then taken out, and the impurities on the membrane surface were washed with distilled water to obtain a chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane.

Example 7

The difference from the above embodiment is:

The imidazole group-containing monomer in step S2 can also be 2,4,5-trimethyl-1-vinylimidazole, 4-ethyl-2,5-dimethyl-1-vinylimidazole, 2- Propyl-4,5-dimethyl-1-vinylimidazole, 4-propyl-2,5-dimethyl-1-vinylimidazole, 2-butyl-4,5-dimethyl-1 -Vinylimidazole, 4-butyl-2,5-dimethyl-1-vinylimidazole, 2,4-diethyl-5-methyl-1-vinylimidazole, 4,5-diethyl -2-Methyl-1-vinylimidazole, 2,4-dibutyl-5-methyl-1-vinylimidazole, 4,5-dibutyl-2-methyl-1-vinylimidazole any kind.

The amino phthalocyanine in step S3 is a transition metal-containing amino phthalocyanine. In addition to iron phthalocyanine, cobalt phthalocyanine and copper phthalocyanine, Mg, Ba, Sc, Ti, V, Cr, Mn, Ni or Zn can also be selected. any kind.

The above-mentioned embodiments are all preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above-mentioned embodiments. Any other changes, modifications, and substitutions may be made without departing from the spirit and principles of this patent. , combination, simplification, should all be equivalent replacement methods, and are all included in the protection scope of this patent.

Claims (9)

1. A main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane, which is characterized in that: it includes a cation exchange membrane layer and an anion exchange membrane layer, and both the cation exchange membrane layer and the anion exchange membrane layer are mainly perfluorocarbons. Chain, nitrogen heterocycle serves as the cationic functional group on the anion exchange membrane layer; among them, the chemical structural formula of the cation exchange membrane layer is: The chemical structural formula of the anion exchange membrane layer is: x is the degree of polymerization of the main chain of the polymer containing chlorotrifluoroethylene structural units, n is the degree of polymerization of the side chain containing sulfonic acid group substituents, m is the degree of polymerization of the side chain containing imidazole substituents, n and m are not an integer of zero; Wherein, the preparation method of the main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane includes the following steps: S1. Preparation of cation exchange membrane liquid: Dissolve the polymer containing chlorotrifluoroethylene structural units in organic solvent I, pass nitrogen to remove oxygen, and after heating, dissolve the polymer in a molar ratio of 1:(20~100):1:2. Polymers containing chlorotrifluoroethylene structural units, sodium styrene sulfonate, CuBr and bipyridine are added to the reaction system, and under nitrogen protection, a constant temperature sulfonation reaction is carried out at 90~130°C for 16~48 hours, and the reaction solution is Put it into a dialysis bag and dialyze in water for 24 hours; dry the solution in the dialysis bag to prepare polychlorotrifluoroethylene grafted sodium styrene sulfonate side chain copolymer; S2. Preparation of anion exchange membrane liquid: Dissolve the polymer containing chlorotrifluoroethylene structural units in organic solvent II, purge nitrogen to remove oxygen, and after heating, follow the steps of polymer containing chlorotrifluoroethylene structural units and vinylimidazole monomers. Mix the base, CuBr and bipyridine at a molar ratio of 1:(20~100):1:2, react at a constant temperature for 16~48h under nitrogen protection, put the reaction solution into a dialysis bag, and dialyze in water for 24h; dry and dialyze The solution in the bag is used to prepare polychlorotrifluoroethylene grafted vinylimidazole side chain copolymer; S3. Preparation of phthalocyanine precursor: KH-560 and transition metal-containing amino phthalocyanine are added into the reaction bottle at a molar ratio of 1:1, add organic solvent III, stir evenly, and react at room temperature for 1 to 3 hours to obtain phthalocyanine-KH560 Precursor; S4. Preparation of the water dissociation catalyst for the bipolar membrane middle layer: Add the phthalocyanine-KH560 precursor obtained through step S3 and the silane coupling agent into the reactor. At the same time, add the acidic catalyst and distilled water to adjust the pH of the reaction system to 2.5~ 3.5, react at 50~60℃ for 1~8h to obtain KH-560 modified phthalocyanine silica sol as a water dissociation catalyst in the middle layer of the bipolar membrane; S5. Preparation of bipolar membrane: Cast the polychlorotrifluoroethylene-grafted sodium styrene sulfonate side chain copolymer solution prepared in step S1 on a clean glass plate, and dry it to prepare a cation exchange membrane layer. Spray KH-560 modified phthalocyanine silica sol on the cation exchange membrane layer. After drying, cast the polychlorotrifluoroethylene-grafted vinylimidazole side chain copolymer obtained in step S2 on the cation exchange membrane layer and dry it. Finally, a chain fluorocarbon-phthalocyanine catalytic layer is obtained as an alkali-resistant bipolar membrane. 2. A kind of main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane as claimed in claim 1, characterized in that: the polymer containing trifluorochloroethylene structural units in the steps S1 and S2 is poly( Any of vinylidene fluoride-chlorotrifluoroethylene), poly(vinylidene fluoride-chlorotrifluoroethylene-tetrafluoroethylene), poly(tetrafluoroethylene-chlorotrifluoroethylene) or polychlorotrifluoroethylene. 3. A kind of main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane as claimed in claim 1, characterized in that: in the step S1, the organic solvent I is N, N-dimethylacetamide, dimethylacetamide, Any one or a combination of two of methyl sulfoxide, N-methylpyrrolidone and N,N-dimethylformamide in any proportion. 4. A main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane as claimed in claim 1, characterized in that: the imidazole group-containing monomer in step S2 is 2-methyl-1-vinyl Imidazole, 2,4-dimethyl-1-vinylimidazole, 2,4,5-trimethyl-1-vinylimidazole, 5-ethyl-2,4-dimethyl-1-vinylimidazole , 2-ethyl-4,5-dimethyl-1-vinylimidazole, 4-ethyl-2,5-dimethyl-1-vinylimidazole, 2-propyl-4,5-dimethyl 1-vinylimidazole, 4-propyl-2,5-dimethyl-1-vinylimidazole, 2-butyl-4,5-dimethyl-1-vinylimidazole, 4-butyl -2,5-Dimethyl-1-vinylimidazole, 2,4-diethyl-5-methyl-1-vinylimidazole, 4,5-diethyl-2-methyl-1-ethylene Any one of 2,4-dibutyl-5-methyl-1-vinylimidazole or 4,5-dibutyl-2-methyl-1-vinylimidazole. 5. A kind of main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane as claimed in claim 1, characterized in that: in the step S2, the organic solvent II is tetrahydrofuran and N, N-dimethylacetamide. , dimethyl sulfoxide, N-methylpyrrolidone, N,N-dimethylformamide or any combination of two in any proportion. 6. A kind of main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane as claimed in claim 1, characterized in that: in the step S3, the organic solvent III is anhydrous methanol, anhydrous ethanol, and isopropyl alcohol. , tetrahydrofuran, acetone or any combination of the two in any proportion. 7. A kind of main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane as claimed in claim 1, characterized in that: the transition metal containing transition metal aminophthalocyanine in step S3 is Fe, Sc, Ti , any one of V, Cr, Mn, Co, Ni, Cu or Zn. 8. A kind of main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane as claimed in claim 1, characterized in that: in the step S4, the silane coupling agent is KH-540, KH-550, KH- 602 or KH-792; the catalyst is any one of hydrochloric acid, formic acid or acetic acid. 9. A kind of main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane as claimed in claim 1, characterized in that: in the step S5, KH-560 modified silicon phthalocyanine is sprayed on the cation exchange membrane layer The sol is produced by any one of aerosol spraying, electrostatic spraying, dipping and pulling, or spin coating.