CN114471179A - Alkali-resistant bipolar film for main chain fluorocarbon-phthalocyanine catalytic layer and preparation method thereof - Google Patents

Abstract

The invention discloses an alkali-resistant bipolar membrane of a main chain fluorocarbon-phthalocyanine catalytic layer and a preparation method thereof, and belongs to the field of electric driving membranes. The anion exchange membrane layer and the cation exchange membrane layer in the bipolar membrane prepared by the invention are They are all based on perfluorocarbon chain as the main chain, which overcomes the defect that hydroxide radicals attack the carbon-oxygen bond in the common main chain. At the same time, the anion and cation exchange membrane layers have similar physical and chemical properties, thus avoiding their peeling during use. possibility to prolong its service life.

Description

Alkali-resistant bipolar film for main chain fluorocarbon-phthalocyanine catalytic layer and preparation method thereof

technical field

The invention relates to a main chain fluorocarbon-phthalocyanine catalytic layer acid-base bipolar film and a preparation method thereof, and belongs to the technical field of electrically driven films.

Background technique

The 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 the electric field, the water molecules in the middle layer of the bipolar membrane are dissociated to generate hydrogen ions and hydroxide radicals, so as to achieve the purpose of generating acid and alkali. The theoretical potential of bipolar membrane water dissociation to produce acid and base is 0.828V, and the theoretical potential of electrolysis of water to produce acid and base is 2.057V. In addition, the water dissociation rate in the interlayer of the bipolar membrane is about 50 million times faster than that in the general case. Therefore, bipolar membrane technology has the characteristics of low energy consumption, high efficiency, and non-polluting products, and has been widely used in various fields such as acid-base production and recovery, marine chemical industry, pollution control and organic synthesis.

Aromatic carbon skeletons such as polyaryletherketone are commonly used bipolar membrane base membrane materials, and quaternary ammonium functional groups are common functional groups in anion exchange membrane layers of bipolar membranes. However, the carbon-oxygen bonds in the aromatic carbon skeleton are easily degraded by hydroxide attack. In addition, due to the attack of hydroxide, the quaternary ammonium functional group is destroyed due to Hoffman reaction, affinity substitution reaction, etc., resulting in a generally low alkali resistance concentration of bipolar membranes. 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 difference in physical and chemical properties between the different layers, it is easy to peel off during use, thereby reducing the the life of the bipolar membrane.

SUMMARY OF THE INVENTION

In order to solve the above problems existing in the prior art, the present invention provides an alkali-resistant bipolar membrane with a main chain fluorocarbon-phthalocyanine catalyst layer and a preparation method thereof. The anion exchange membrane layer and the cation exchange membrane layer in the bipolar membrane are both With perfluorocarbon as the main chain, it overcomes the defect that the carbon-oxygen bond in the common main chain is easily degraded by hydroxide attack, and the anion and cation exchange membrane layer has similar physical and chemical properties, thus reducing its peeling during use. possibility to extend its service life.

The technical scheme of the present invention is as follows:

One of the objectives of the present invention is to provide a main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane, comprising a cation exchange membrane layer and an anion exchange membrane layer, both of which are made of perfluorocarbon As the main chain, nitrogen heterocycle is used as the cationic functional group on the anion exchange membrane layer; wherein, 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 unit, n is the degree of polymerization of the side chain of the substituent containing the sulfonic acid group, m is the degree of polymerization of the side chain of the imidazole substituent, and n and m are different An integer of zero.

The object of the present invention is also to provide a preparation method of a main chain carbon fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar film, which specifically comprises the following steps:

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

S2. Preparation of anion exchange membrane liquid: Dissolve the polymer containing chlorotrifluoroethylene structural unit in organic solvent II, pass nitrogen to remove oxygen, and after heating up, follow the steps of the polymer containing chlorotrifluoroethylene structural unit, the imidazole group-containing monolayer The molar ratio of urea, uBr and bipyridine is 1:(20～100):1:2, and under nitrogen protection, the reaction is held at a constant temperature for 16～48h, the reaction solution is put into a dialysis bag, and dialyzed in water for 24h; oven-drying dialysis solution in the bag to obtain polychlorotrifluoroethylene grafted vinylimidazole side chain copolymer (PCTEF-g-PVIm);

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

S4. Preparation of bipolar membrane interlayer water dissociation catalyst: The phthalocyanine-KH560 precursor obtained in step S3 is added to the reactor together with the silane coupling agent, and the acidic catalyst and distilled water are added at the same time, and the pH of the reaction system is adjusted to 2.5～ 3.5, react at 50～60℃ for 1～8h to obtain KH-560 modified phthalocyanine silica sol as the bipolar membrane interlayer water dissociation catalyst;

S5. Preparation of bipolar membrane: casting the polychlorotrifluoroethylene-grafted sodium styrene sulfonate side chain copolymer solution obtained in step S1 on a clean glass plate, drying to prepare a cation exchange membrane layer, KH-560 modified phthalocyanine silica sol was sprayed on the cation exchange membrane layer, and after drying, the polychlorotrifluoroethylene grafted vinylimidazole side chain copolymer obtained in step S2 was cast on the cation exchange membrane layer, and dried. Then, the alkali-resistant bipolar film of the chain fluoro-phthalocyanine catalyst layer is obtained.

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

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

Further, in the step S2, the imidazole group-containing monomers are 2-methyl-1-vinylimidazole, 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-vinylimidazole, 2,4-dibutyl-5-methyl-1-vinylimidazole, 4,5-di Any of butyl-2-methyl-1-vinylimidazole.

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

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

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

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

Compared with the prior art, 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, wherein both the cation exchange membrane layer and the anion exchange membrane layer are fluorocarbon main chains, which can overcome the aromatic The carbon-oxygen bond in the carbon skeleton is easily attacked and degraded by hydroxide. 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. 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, so that the The acid-base concentration is increased.

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

Detailed ways

The present invention will be further described below in conjunction with the 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 a numerical range, the endpoints of each range, the endpoints of each range and the 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 considered as specifically disclosed herein.

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

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

Example 1

A main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar membrane, comprising a cation exchange membrane layer and an anion exchange membrane layer, the cation exchange membrane layer and the anion exchange membrane layer are both based on perfluorocarbon as the main chain, and nitrogen heterocycle as the main chain. The cationic functional group on the anion exchange membrane layer; wherein, 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 unit, n is the degree of polymerization of the side chain of the substituent containing the sulfonic acid group, m is the degree of polymerization of the side chain of the imidazole substituent, and n and m are different An integer of zero.

Example 2

A preparation method of a main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar film, comprising 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 120mL of N-methylpyrrolidone, pass nitrogen to remove oxygen, and heat up to After 120°C, 126.3g of sodium styrene sulfonate, 4.36g of CuBr and 4.76g of bipyridine were added, and under the protection of nitrogen, a constant temperature sulfonation reaction was carried out at 120°C for 24h, and the reaction solution was poured into an alcohol/water mixed solvent (V /V=1:1), the graft polymer was precipitated, and then put into a dialysis bag, and dialyzed in water for 24h to remove copper ions, bromide ions, bipyridine and unreacted monomers; collect the solution in the dialysis bag, Concentrating and drying to obtain 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 10 g of poly(vinylidene fluoride-chlorotrifluoroethylene) (the copolymer contains 25% chlorotrifluoroethylene), dissolve it in 120 mL of N,N-dimethylformamide, and pass nitrogen through it. Remove oxygen, heat up to 80°C, add 74.44g of 2-methyl-1-vinylimidazole, 4.36g of CuBr and 10.56g of pentamethyldiethyltriamine, under nitrogen protection, react at constant temperature for 48h, and put the reaction solution into In the dialysis bag, dialysis in water for 24h to remove copper ions, bromide ions, bipyridine and unreacted monomers; collect the solution in the dialysis bag, concentrate, and dry to obtain polychlorotrifluoroethylene grafted vinylimidazole side chains Copolymer (PCTEF-g-PVIm); wherein, the grafting reaction is as follows:

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

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

S5. Preparation of bipolar membrane: casting the polychlorotrifluoroethylene-grafted sodium styrene sulfonate side chain copolymer solution obtained in step S1 on a clean glass plate, drying to prepare a cation exchange membrane layer, The KH-560 modified iron phthalocyanine silica sol was sprayed on the cation exchange membrane layer by electrostatic spraying. After drying, the polytrifluorochloroethylene grafted vinylimidazole side chain copolymer obtained in step S2 was cast on the cation exchange membrane. After drying, the negative side was immersed in methyl iodide tetrahydrofuran solution for 5 hours and taken out, and the impurities on the membrane surface were washed with distilled water to obtain an alkali-resistant bipolar membrane of the chain fluoro-phthalocyanine catalytic layer.

Example 3

A preparation method of a main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar film, comprising 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 120mL of dimethyl sulfoxide. Oxygen, heated to 80°C, added 151.6g of sodium styrene sulfonate, 4.36g of CuBr and 10.56g of pentamethyldiethyltriamine, under nitrogen protection, at 80°C for a constant temperature sulfonation reaction for 48h, the reaction The solution was poured into ethanol, and the graft polymer was precipitated, which was then put into a dialysis bag and dialyzed in water for 24 hours to remove copper ions, bromide ions, bipyridine and unreacted monomers; the solution in the dialysis bag was collected, concentrated, dried and dried. Dry to obtain 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), dissolve it in 120mL of tetrahydrofuran, pass nitrogen to remove oxygen, and heat up. After reaching 80°C, 74.4g of 5-ethyl-2,4-dimethyl-1-vinylimidazole, 4.36g of CuBr and 4.76g of bipyridine were added. Under nitrogen protection, the reaction was carried out at a constant temperature for 16h, and the reaction solution was put into a dialysis bag. in water dialysis for 24h to remove copper ions, bromide ions, bipyridine and unreacted monomers; collect the solution in the dialysis bag, concentrate and dry to obtain polychlorotrifluoroethylene grafted vinylimidazole side chain copolymer (PCTEF-g-PVIm); wherein, the grafting reaction is as follows:

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

S4. Preparation of bipolar membrane interlayer water dissociation catalyst: Weigh 8.13 g of copper phthalocyanine-KH560 precursor obtained in step S3 and add 1.11 g of silane coupling agent KH602 to the reactor, and at the same time add 18 mL of ethanol, 7.5 mL of Distilled water and 0.6 mL of formic acid were used to adjust the pH of the reaction system to 2.5, and the reaction was carried out at 50 °C for 2 h to obtain KH-560 modified copper phthalocyanine silica sol as the bipolar membrane interlayer water dissociation catalyst. The reaction is as follows:

S5. Preparation of bipolar membrane: casting the polychlorotrifluoroethylene-grafted sodium styrene sulfonate side chain copolymer solution obtained in step S1 on a clean glass plate, drying to prepare a cation exchange membrane layer, KH-560 modified copper phthalocyanine silica sol was sprayed on the cation exchange membrane layer by spin coating, and after drying, the polytrifluorochloroethylene grafted vinylimidazole side chain copolymer obtained in step S2 was cast on the cation exchange membrane. After drying, the negative side was immersed in methyl iodide tetrahydrofuran solution for 5 hours and taken out, and the impurities on the membrane surface were washed with distilled water to obtain an alkali-resistant bipolar membrane of the chain fluoro-phthalocyanine catalytic layer.

Example 4

A preparation method of a main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar film, comprising the following steps:

S1. Preparation of cation exchange membrane liquid: Weigh 10g of poly(tetrafluoroethylene-chlorotrifluoroethylene) (the copolymer contains 25% chlorotrifluoroethylene), dissolve it in 120mL of N,N-dimethylacetamide, and pass nitrogen through it. After removing oxygen, the temperature was raised to 130 °C, and 126.3 g of sodium styrene sulfonate, 4.36 g of CuBr and 10.56 g of pentamethyldiethyltriamine were added. In a liquid dialysis bag, dialysis in water for 24 hours to remove copper ions, bromide ions, bipyridine and unreacted monomers; collect the solution in the dialysis bag, concentrate, and dry to obtain 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 10 g of poly(tetrafluoroethylene-chlorotrifluoroethylene) (the copolymer contains 25% chlorotrifluoroethylene) and dissolve it in 120 mL of N-methylpyrrolidone, pass nitrogen to remove oxygen, and heat up. After reaching 85°C, 70.4g of 2,4-dimethyl-1-vinylimidazole, 4.36g of CuBr and 4.76g of bipyridine were added. Under the protection of nitrogen, the reaction was carried out at a constant temperature for 18 hours. The reaction solution was put into a dialysis bag and dialyzed against water. 24h, remove copper ion, bromide ion, bipyridine and unreacted monomer; collect the solution in the dialysis bag, concentrate, and dry to obtain polychlorotrifluoroethylene grafted vinylimidazole side chain copolymer (PCTEF-g- PVIm); wherein, the grafting reaction is as follows:

S3. Preparation of phthalocyanine precursor: Weigh 2.36g KH-560 and 5.73g cobalt phthalocyanine into a reaction flask, add 35mL of tetrahydrofuran, stir evenly, react at room temperature for 2h, and remove the solvent by distillation to obtain cobalt phthalocyanine-KH560 precursor;

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

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

Example 5

A preparation method of a main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar film, comprising the following steps:

S1. Preparation of cation exchange membrane liquid: Weigh 10 g of polychlorotrifluoroethylene (copolymer contains 25% chlorotrifluoroethylene) and dissolve it in 120 mL of N,N-dimethylformamide, pass nitrogen to remove oxygen, and heat up to 110 140.0 styrene sulfonate sodium, 4.36g CuBr and 10.76g pentamethyldiethyltriamine were added after ℃, and under the protection of nitrogen, a constant temperature sulfonation reaction was carried out at 110 ℃ for 40h, and the reaction solution was put in a dialysis bag and placed in a dialysis bag. Water dialysis for 24h to remove copper ions, bromide ions, bipyridine and unreacted monomers; collect the solution in the dialysis bag, concentrate, and dry to obtain 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 10 g of polychlorotrifluoroethylene (the copolymer contains 25% chlorotrifluoroethylene) and dissolve it in 120 mL of N,N-dimethylacetamide, pass nitrogen to remove oxygen, and heat up to 80 After ℃, 89.68g 2-ethyl-4,5-dimethyl-1-vinylimidazole, 4.36g CuBr and 10.56g pentamethyldiethyltriamine were added, and the reaction was carried out at constant temperature for 24h under nitrogen protection, and the reaction solution was Put it into a dialysis bag, and dialyze it in water for 24 hours to remove copper ions, bromide ions, bipyridine and unreacted monomers; collect the solution in the dialysis bag, concentrate, and dry to obtain polychlorotrifluoroethylene grafted vinylimidazole Side chain copolymer (PCTEF-g-PVIm); wherein, the grafting reaction is as follows:

S3. Preparation of phthalocyanine precursor: Weigh 2.36g KH-560 and 5.70g cobalt phthalocyanine into the reaction flask, add 35mL isopropanol, stir evenly, react at room temperature for 3h, and remove the solvent by distillation to obtain the cobalt phthalocyanine-KH560 precursor ;

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

S5. Preparation of bipolar membrane: casting the polychlorotrifluoroethylene-grafted sodium styrene sulfonate side chain copolymer solution obtained in step S1 on a clean glass plate, drying to prepare a cation exchange membrane layer, KH-560 modified cobalt phthalocyanine silica sol was sprayed on the cation exchange membrane layer by aerosol spraying method. After drying, the polytrifluorochloroethylene grafted vinylimidazole side chain copolymer obtained in step S2 was cast on the cation exchange On the membrane layer, after drying, the negative surface is soaked in methyl iodide tetrahydrofuran solution for 5 hours, taken out, and the impurities on the membrane surface are washed with distilled water to obtain an alkali-resistant bipolar membrane of the chain fluoro-phthalocyanine catalytic layer.

Example 6

A preparation method of a main chain fluorocarbon-phthalocyanine catalytic layer alkali-resistant bipolar film, comprising 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 120mL of N-methylpyrrolidone, pass nitrogen to remove oxygen, and heat up. After reaching 130 °C, 126.3 g of sodium styrene sulfonate, 4.36 g of CuBr and 4.76 g of bipyridine were added. Under the protection of nitrogen, a constant temperature sulfonation reaction was carried out at 130 ° C for 20 h. The reaction solution was poured into ethanol, and the graft was precipitated. The polymer and the precipitate were put into a dialysis bag and dialyzed in water for 24 hours to remove copper ions, bromide ions, bipyridine and unreacted monomers; the solution in the dialysis bag was collected, concentrated and dried to obtain 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 10 g of poly(vinylidene fluoride-chlorotrifluoroethylene) (the copolymer contains 25% chlorotrifluoroethylene), dissolve it in 120 mL of dimethyl sulfoxide, pass nitrogen to remove oxygen, and heat up to After 80°C, 89.68g of 5-ethyl-2,4-dimethyl-1-vinylimidazole, 4.36g of CuBr and 10.56g of pentamethyldiethyltriamine were added, and the reaction was carried out at a constant temperature for 18h under nitrogen protection. The solution was put into a dialysis bag, and dialyzed in water for 24 hours to remove copper ions, bromide ions, bipyridine and unreacted monomers; the solution in the dialysis bag was collected, concentrated and dried to obtain polychlorotrifluoroethylene grafted vinyl. Imidazole side chain copolymer (PCTEF-g-PVIm); wherein, the grafting reaction is as follows:

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

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

S5. Preparation of bipolar membrane: casting the polychlorotrifluoroethylene-grafted sodium styrene sulfonate side chain copolymer solution obtained in step S1 on a clean glass plate, drying to prepare a cation exchange membrane layer, The KH-560 modified cobalt phthalocyanine silica sol was sprayed on the cation exchange membrane layer by electrostatic spraying. After drying, the polytrifluorochloroethylene grafted vinylimidazole side chain copolymer obtained in step S2 was cast on the cation exchange membrane. After drying, the negative side was immersed in methyl iodide tetrahydrofuran solution for 5 hours and taken out, and the impurities on the membrane surface were washed with distilled water to obtain an alkali-resistant bipolar membrane of the chain fluoro-phthalocyanine catalytic layer.

Example 7

The difference from the above embodiment is that:

The imidazole group-containing monomer in the step S2 may 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 of the .

In the step S3, the amino phthalocyanine 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 of the .

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, and any other changes, modifications and substitutions made without departing from the spirit and principle of this patent , combination and simplification shall all be equivalent replacement methods, which are all included in the protection scope of this patent.

Claims (10)

1. The alkali-resistant bipolar membrane with the main chain fluorocarbon-phthalocyanine catalyst layer is characterized in that: the membrane comprises a cation exchange membrane layer and an anion exchange membrane layer, wherein the cation exchange membrane layer and the anion exchange membrane layer both use perfluorocarbon as a main chain, and nitrogen heterocycles are used as cation functional groups on the anion exchange membrane layer; wherein, the chemical structural formula of the cation exchange membrane layer is as follows:

the chemical structural formula of the anion exchange membrane layer is as follows:

wherein x is the polymerization degree of a polymer main chain containing a chlorotrifluoroethylene structural unit, n is the polymerization degree of a side chain containing a sulfonic acid group substituent group, m is the polymerization degree of a side chain containing an imidazole substituent group, and n and m are integers which are not zero.

2. A preparation method of an alkali-resistant bipolar membrane with a main chain fluorocarbon-phthalocyanine catalyst layer is characterized by comprising the following steps:

s1, preparation of cation exchange membrane liquid: dissolving a polymer containing a chlorotrifluoroethylene structural unit in an organic solvent I, introducing nitrogen to remove oxygen, heating, adding the polymer containing the chlorotrifluoroethylene structural unit, sodium styrene sulfonate, CuBr and bipyridine into a reaction system according to a molar ratio of 1 (20-100): 1:2, carrying out constant-temperature sulfonation reaction for 16-48 h at 90-130 ℃ under the protection of nitrogen, filling a reaction solution into a dialysis bag, and dialyzing for 24h in water; drying the solution in the dialysis bag to prepare the polytrifluorochloroethylene grafted sodium styrene sulfonate side chain copolymer;

s2, preparation of anion exchange membrane liquid: dissolving a polymer containing a chlorotrifluoroethylene structural unit in an organic solvent II, introducing nitrogen to remove oxygen, heating, mixing according to the molar ratio 1 (20-100): 1:2 of the polymer containing the chlorotrifluoroethylene structural unit, a monomer containing an imidazole group, uBr and bipyridine, reacting for 16-48 h at a constant temperature under the protection of nitrogen, filling a reaction solution into a dialysis bag, and dialyzing for 24h in water; drying the solution in the dialysis bag to prepare a polytrifluorochloroethylene grafted vinyl imidazole side chain copolymer;

s3, preparation of phthalocyanine precursor: adding KH-560 and amino phthalocyanine into a reaction bottle according to a molar ratio of 1:1, adding an organic solvent III, uniformly stirring, and reacting at room temperature for 1-3 h to obtain a phthalocyanine-KH 560 precursor;

s4, preparation of bipolar membrane intermediate layer water dissociation catalyst: adding the phthalocyanine-KH 560 precursor obtained in the step S3 and a silane coupling agent into a reactor, adding an acid catalyst and distilled water, adjusting the pH of a reaction system to 2.5-3.5, and reacting at 50-60 ℃ for 1-8 h to obtain KH-560 modified phthalocyanine silica sol serving as a bipolar membrane intermediate layer water dissociation catalyst;

s5, preparing a bipolar membrane: and (2) casting the polychlorotrifluoroethylene grafted sodium styrene sulfonate side chain copolymer solution prepared in the step (S1) on a cleaned glass plate, drying to prepare a cation exchange membrane layer, spraying KH-560 modified phthalocyanine silica sol on the cation exchange membrane layer, drying in the air, casting the polychlorotrifluoroethylene grafted vinyl imidazole side chain copolymer obtained in the step (S2) on the cation exchange membrane layer, and drying to obtain the alkali-resistant bipolar membrane of the chain fluorocarbon-phthalocyanine catalyst layer.

3. The method for preparing the alkali-resistant bipolar membrane with the main chain fluorocarbon-phthalocyanine catalytic layer as claimed in claim 2, wherein: the polymer containing the chlorotrifluoroethylene structural unit in the steps S1 and S2 is any one of poly (vinylidene fluoride-chlorotrifluoroethylene), poly (vinylidene fluoride-chlorotrifluoroethylene-tetrafluoroethylene), poly (tetrafluoroethylene-chlorotrifluoroethylene) or polychlorotrifluoroethylene.

4. The method for preparing the alkali-resistant bipolar membrane with the main chain fluorocarbon-phthalocyanine catalytic layer as claimed in claim 2, wherein: in the step S1, the organic solvent I is any one or a combination of two of N, N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone and N, N-dimethylformamide in any proportion.

5. The method for preparing the alkali-resistant bipolar membrane with the main chain fluorocarbon-phthalocyanine catalytic layer as claimed in claim 2, wherein: in step S2, the imidazole-containing monomer is selected from the group consisting of 2-methyl-1-vinylimidazole, 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-vinylimidazole, 2, 4-dibutyl-5-methyl-1-vinylimidazole or 4, 5-dibutyl-2-methyl-1-vinylimidazole.

6. The method for preparing the alkali-resistant bipolar membrane with the main chain fluorocarbon-phthalocyanine catalytic layer as claimed in claim 2, wherein: in the step S2, the organic solvent II is one or a combination of two of tetrahydrofuran, N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone and N, N-dimethylformamide in any proportion.

7. The method for preparing the alkali-resistant bipolar membrane with the main chain fluorocarbon-phthalocyanine catalytic layer as claimed in claim 2, wherein: in the step S3, the organic solvent iii is any one of or a combination of two of anhydrous methanol, anhydrous ethanol, isopropanol, tetrahydrofuran and acetone at any ratio.

8. The method for preparing the alkali-resistant bipolar membrane with the main chain fluorocarbon-phthalocyanine catalytic layer as claimed in claim 2, wherein: in step S3, the amino phthalocyanine is 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.

9. The method for preparing alkali-resistant bipolar membrane with main chain fluorocarbon-phthalocyanine catalytic layer according to claim 2, wherein: the silane coupling agent in the step S4 is any one of KH540, KH550, KH602 or KH 792; the catalyst is any one of hydrochloric acid, formic acid or acetic acid.

10. The method for preparing the alkali-resistant bipolar membrane with the main chain fluorocarbon-phthalocyanine catalytic layer as claimed in claim 2, wherein: in the step S5, the KH-560 modified phthalocyanine silica sol is sprayed on the cation exchange membrane layer by any one of aerosol spraying, electrostatic spraying, dipping-pulling method, and spin coating.