Perfluorinated ion exchange resin and preparation method thereof and anion exchange membrane

Abstract

This invention provides an ether-free perfluorinated anion exchange resin having the structure of formula (I), where Rf1 represents a direct bond, a C1-C20 straight-chain or branched alkylene group, and the carbon atoms therein can be selectively replaced by O; m and n are each independently selected from integers between 1 and 200, and the side chain is a spirocyclic quaternary ammonium salt group. The ether-free perfluorinated anion exchange resin provided by this invention can effectively improve the resin's alkali resistance and oxidation resistance. The introduction of spirocyclic quaternary ammonium salt groups into the side chain can further improve the resin's alkali resistance and ion conductivity.

Description

Technical Field

[0001] The present invention relates to the field of fuel cell materials, and in particular to a perfluorinated ion exchange resin and a preparation method thereof, and an anion exchange membrane. Background Art

[0002] Alkaline anion exchange membrane fuel cells (AEMFCs) have many advantages over proton exchange membrane fuel cells: the alkaline environment has little corrosion on the system, the anode oxidation rate is faster, the electrode reaction has lower requirements for catalyst selectivity, non-precious metals (such as Ni and Ag) can be used as catalysts to reduce costs, and the feed liquid (especially methanol) permeability is low. Based on the above advantages, anion exchange membrane fuel cells have become a hot topic of research in recent years. As the core component of AEMFs, the alkaline anion exchange membrane plays an important role, separating the anode and cathode while transferring hydroxide from the cathode to the anode. Most anion exchange membranes are based on the main chain structure of hydrocarbon polymers, and the side chains contain quaternary ammonium groups. In alkaline solutions, the membranes will decay to varying degrees, causing membrane damage.

[0003] Some researchers have proposed using a main chain containing ether oxygen bonds as the base material, and using long hydrophobic side chains to separate ion exchange groups (such as trimethylamine, piperidine, imidazole, etc.) to promote the formation of a microphase separation structure in the membrane and promote the transfer of ions in the membrane. However, this type of exchange membrane is prone to degradation reactions under alkaline conditions, which shortens the life of the membrane and is not conducive to the stable operation of the electrolytic cell.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The main purpose of the present invention is to provide a perfluoro ion exchange resin without an ether bond, so as to improve the technical problem that the membrane formed by the existing ion exchange resin using an ether oxygen-containing main chain as a substrate and introducing an ion exchange group in a long hydrophobic side chain is prone to degradation reaction under alkaline conditions, resulting in a shortened membrane life and being unfavorable for the stable operation of the electrolytic cell. In order to achieve the above purpose, according to one aspect of the present invention, a perfluoro anion exchange resin without an ether bond is provided, and the perfluoro anion exchange resin without an ether bond has the following formula I) structure:

[0006]

[0007] In the above formula (I), Rf1 represents a direct bond, a C1-C20 straight chain or branched alkylene group, and the carbon atoms therein may be selectively substituted by O; m and n are each independently selected from integers between 1 and 200; and R has the following general formula (II):

[0008]

[0009] In the above formula (II), each R1a , R 1b and R 1c Each independently represents hydrogen, C1-C20 straight or branched alkyl, C3-C20 cycloalkyl, C4-C20 cycloalkylalkyl, C4-C20 alkylcycloalkyl, -NO2, -OR A 、-COR A 、-COOR A 、-SR A 、-SO2R A or-CONR A R B , where R A and R B Each independently represents the following first group: any one of hydrogen, C1-C20 straight chain or straight chain alkyl, C3-C20 cycloalkyl, C4-C20 cycloalkylalkyl, C4-C20 alkylcycloalkyl, C6-C20 phenyl, C2-C20 heterocyclic group, and the carbon atoms in the first group can be selectively substituted by N, O, S; A represents *N*, *NR1B* or *C(R2)R3B*, wherein B represents *N*R4, *S*, *O*, a group represented by formula (III) or a group represented by formula (IV):

[0010]

[0011] Wherein, R1 and R3 each independently represent the following second group: a direct bond, a C1-C20 straight chain or branched alkylene group, a C3-C20 cycloalkylene group, a C4-C20 cycloalkylalkylene group, a C4-C20 alkylcycloalkylene group, a C4-C20 alkylcycloalkylene group, and the carbon atoms in the second group may be selectively substituted by N, O, or S;

[0012] R2, R4, each R 2a , R 2b , R 2c , R 2d , R 3a , R 3b , R 3c and R 3d Each independently selected from the following third groups: hydrogen, C1-C20 straight chain or branched alkyl, C3-C20 cycloalkyl, C4-C20 cycloalkylalkyl, C4-C20 alkylcycloalkyl, -NO2, -OR A 、-COR A 、-COOR A 、-SR A 、-SO2R A or-CONR A R B, and the carbon atoms in the third group can be selectively substituted by N, O, or S.

[0013] Furthermore, Rf1 is a direct bond, a C1-C10 straight chain or branched alkylene group, and the carbon atoms therein may be selectively substituted by O.

[0014] Furthermore, in the formula (II), A represents *N*, *NR1B* or *C(R2)R3B*, and B represents *N*R4, *S*, *O*, a group represented by the formula (III) or a group represented by the formula (IV);

[0015] Wherein, said R2, R3, each R 1a , R 1b , R 1c , R 2a , R 2b , R 2c , R 2d , R 3a , R 3b , R 3c and R 3d Each independently represents hydrogen, methyl, ethyl, tert-butyl, -NO2, -OR A 、-COR A 、-COOR A 、-SR A 、-SO2R A or-CONR A R B , where R A and R B Each independently represents hydrogen, a C1-C10 straight chain or a straight chain alkyl; R1 and R3 each independently represent a direct bond, a C1-C10 straight chain or a straight chain alkyl, wherein the carbon atoms may be selectively substituted by O or S; and when R1 is a direct bond, B represents *N*R4, *S* or *O*; when R3 is a direct bond, B represents *N*R4, *S* or *O*.

[0016] Further, the Rf1 is a direct bond, a C1-C6 straight chain or branched alkylene group, and the carbon atoms therein may be selectively substituted by O; and the R is selected from at least one of the following compounds:

[0017]

[0018] In order to achieve the above object, according to one aspect of the present invention, a method for preparing a perfluoro ion exchange resin without an ether bond is provided, the preparation method comprising: step S1, mixing a halogen-containing perfluoro resin with an amine compound for a first reaction to obtain a perfluoroamide resin; step S2, mixing the perfluoroamide resin with 1,5-dihalopentane for a second reaction to obtain the perfluoro anion resin without an ether bond; wherein in step S1, the halogen-containing perfluoro resin has the following formula (v):

[0019]

[0020] In the above formula (V), Rf1, m, and n have the same definitions as in the first aspect, and X represents a halogen; in the step S2, the amine compound has a structure as shown in the following formula (VI):

[0021]

[0022] In the above formula (VI), each R 1a , R 1b , R 1c It has the same definition as in the first typical embodiment described above; D represents AH, and A has the same definition as in the first typical embodiment described above.

[0023] Furthermore, the amine compound is selected from at least one of the following compounds:

[0024]

[0025] wherein o, p, q and w are each independently selected from integers between 1 and 3.

[0026] Furthermore, in step S1, the halogen-containing perfluoro resin is mainly copolymerized by halogen-containing perfluoroolefin and tetrafluoroethylene; wherein the perfluoroolefin monomer structure is:

[0027] Rf1 and X have the same meanings as above.

[0028] Furthermore, in the step S1, the molar ratio of the -X group in the halogen-containing perfluoro resin to the amine compound is 1:5-10, preferably 1:5-8.

[0029] Furthermore, the halogen-containing perfluoro resin and the amine compound are mixed in a first organic solvent to carry out the first reaction, the temperature of the first reaction is 30-120° C., and the time of the first reaction is 12-48 hours; preferably, the first reaction is carried out under the action of a first acid binding agent, and the first acid binding agent is added to the first organic solvent.

[0030] Furthermore, the first organic solvent includes at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide or ethyl acetate.

[0031] Furthermore, the first acid binding agent is an alkaline substance, and the alkaline substance is preferably at least one of sodium hydroxide, sodium carbonate, sodium bicarbonate, cesium carbonate, lithium hydride or sodium hydride.

[0032] Furthermore, in S2, the molar ratio of the amide group in the perfluoroamide resin to the dihalopentane is 1:5-10, preferably 1:5-8.

[0033] Furthermore, the perfluoroamide resin and the dihalopentane are mixed in a second organic solvent to carry out the second reaction, the temperature of the second reaction is 30 to 80° C., and the time of the second reaction is 12 to 48 hours; preferably, the second reaction is carried out under the action of a second acid binding agent, and the second acid binding agent is added to the second organic solvent.

[0034] Furthermore, the second organic solvent includes at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide or ethyl acetate.

[0035] Furthermore, the second acid binding agent is an alkaline substance, and the alkaline substance is preferably at least one of sodium hydroxide, sodium carbonate, sodium bicarbonate, cesium carbonate, lithium hydride or sodium hydride.

[0036] Further, the dihalopentane includes at least one of dichloropentane and dibromopentane.

[0037] According to the third aspect of the present invention, there is also provided an anion exchange membrane, the main material of which is any one of the ether-bond-free perfluoro ion exchange resins provided in the above-mentioned first typical embodiment or the ether-bond-free perfluoro ion exchange resin prepared according to the preparation method provided in the above-mentioned second typical embodiment.

[0038] According to a fourth aspect of the present invention, there is also provided application of the above anion exchange membrane in a fuel cell.

[0039] By applying the technical solution of the present invention, the ion exchange resin having the structure of the above formula (I) has a main chain of a perfluoro ether-free structure, which can effectively improve the alkali stability and oxidation stability of the resin, and introduces a spirocyclic quaternary ammonium salt group into the side chain, which can further improve the alkali stability of the resin and improve the ion conductivity. The ether-free ion exchange resin provided by the present invention has excellent alkali resistance and antioxidant properties, and the life of the ion exchange membrane formed by the ether-free ion exchange resin as the main material is effectively improved, which can further promote the stable operation of the electrolytic cell. DETAILED DESCRIPTION

[0040] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0041] As analyzed in the background technology of this application, the existing membrane formed by using a resin containing an ether oxygen bond as a main chain as a substrate and introducing an ion exchange group into a hydrophobic side chain is prone to degradation reaction under alkaline conditions, resulting in a shortened membrane life and being detrimental to the stable operation of the battery. To solve this problem, this application provides an ether-free perfluorinated ion exchange resin and a preparation method thereof and an anion exchange membrane.

[0042] It should be noted that, in the present application, "perfluorinated ion exchange resin without ether bonds" means that there are no ether bonds in the main chain, and there is no limitation on whether there are ether bonds in the side chain.

[0043] In a typical embodiment of the present application, the present application provides an ether bond-free perfluorinated ion exchange resin, and the ether bond-free perfluorinated ion exchange resin has the following formula (I):

[0044]

[0045] In the above formula (I), Rf1 represents a direct bond, a C1-C20 straight chain or branched alkylene group, and the carbon atoms therein may be selectively substituted by O; m and n are each independently selected from integers between 1 and 200, such as 1, 2, 5, 8, 10, 20, 50, 80, 100, 150 or 200; and R has the following general formula (II):

[0046]

[0047] In the above formula (II), each R 1a , R 1b and R 1c Each independently represents hydrogen, C1-C20 straight chain or straight chain alkyl, C3-C20 cycloalkyl, C4-C20 cycloalkylalkyl, C4-C20 alkylcycloalkyl, -NO2, -OR A 、-COR A 、 -COOR A 、-SR A 、-SO2R A or-CONR A R B , where R A and R BEach independently represents the following first group: any one of hydrogen, C1-C20 straight chain or straight chain alkyl, C3-C20 cycloalkyl, C4-C20 cycloalkylalkyl, C4-C20 alkylcycloalkyl, C6-C20 phenyl, C2-C20 heterocyclic group, and the carbon atoms in the first group can be selectively substituted by N, O, S; A represents *N*, *NR1B* or *C(R2)R3B*, wherein B represents *N*R4, *S*, *O*, a group represented by formula (III) or a group represented by formula (IV):

[0048]

[0049] Wherein, R1 and R3 each independently represent the following second group: a direct bond, a C1-C20 straight chain or branched alkylene group, a C3-C20 cycloalkylene group, a C4-C20 cycloalkylalkylene group, a C4-C20 alkylcycloalkylene group, and the carbon atoms in the second group may be selectively substituted by N, O, or S;

[0050] R2, R4, each R 2a , R 2b , R 2c , R 2d , R 3a , R 3b , R 3c and R 3d Each independently selected from the following third groups: hydrogen, C1-C20 straight chain or branched alkyl, C3-C20 cycloalkyl, C4-C20 cycloalkylalkyl, C4-C20 alkylcycloalkyl, -NO2, -OR A 、-COR A 、-COOR A 、-SR A 、-SO2R A or-CONR A R B , and the carbon atoms in the third group can be selectively substituted by N, O, or S.

[0051] By applying the technical solution of the present invention, the ion exchange resin having the structure of the above formula (I) has a main chain of a perfluoro ether-free structure, which can effectively improve the alkali stability and oxidation stability of the resin, and introduces a spirocyclic quaternary ammonium salt group into the side chain, which can further improve the alkali stability of the resin and improve the ion conductivity. The ether-free ion exchange resin provided by the present invention has excellent alkali resistance and antioxidant properties, and the life of the ion exchange membrane formed by the ether-free ion exchange resin as the main material is effectively improved, which can further promote the stable operation of the electrolytic cell.

[0052] In some embodiments of the present application, in the above formula (I), when Rf1 is a direct bond, a C1-C10 straight chain or branched alkylene group, and the carbon atoms therein can be selectively replaced by O, it is more conducive to the formation of a long-range ordered structure of the ether-free perfluorinated ion exchange resin, thereby further improving the ion conductivity.

[0053] In some embodiments of the present application, in the above formula (II), when A represents *N*, *NR1B* or *C(R2)R3B*, and B represents *N*R4, *S*, *O*, a group represented by formula (III) or a group represented by formula (IV), R2, R3, each R 1a , R 1b , R 1c , R 2a , R 2b , R 2c , R 2d , R 3a , R 3b , R 3c and R 3d Each independently represents hydrogen, methyl, ethyl, tert-butyl, -NO2, -OR A 、 -COR A 、-COOR A 、-SR A 、-SO2R A or-CONR A R B , where R A and R B Each independently represents hydrogen, a C1-C10 straight chain or a straight-chain alkyl group; R1 and R3 each independently represent a direct bond, a C1-C10 straight chain or a straight-chain alkyl group, wherein the carbon atoms may be selectively substituted by O or S; and when R1 is a direct bond, B represents *N*R4, *S* or *O*; when R3 is a direct bond, B represents *N*R4, *S* or *O*, which is more conducive to further improving the ionic conductivity of the ether-free perfluoro ion exchange resin.

[0054] In some embodiments of the present application, in the above formula (I), Rf1 is a direct bond, a straight chain or branched alkylene group of C1-C6, and the carbon atoms therein can be selectively substituted by O; when R is selected from at least one of the following structural compounds, the ether-free ion exchange resin has a more long-range ordered structure and has a higher ionic conductivity.

[0055]

[0056] wherein o, p, q and w are each independently selected from an integer between 1 and 3, such as 1, 2 or 3.

[0057] In another typical embodiment of the present application, a method for preparing a perfluoro ion exchange resin without an ether bond is also provided. The preparation method comprises: step S1, mixing a halogen-containing perfluoro resin with an amine compound for a first reaction to obtain a perfluoroamide resin; step S2, mixing the perfluoroamide resin with 1,5-dihalopentane for a second reaction to obtain a perfluoro anion resin without an ether bond; wherein in step S1, the halogen-containing perfluoro resin has the following formula (V):

[0058]

[0059] In the above formula (V), Rf1, m, and n have the same definitions as in the first typical embodiment and are not repeated here; X represents a halogen, including but not limited to -Br, -Cl, etc.

[0060] In the step S2, the amine compound has a structure shown in the following formula (VI):

[0061]

[0062] In the above formula (VI), each R 1a , R 1b , R 1c It has the same definition as in the first typical embodiment; D represents AH, and A has the same definition as in the first typical embodiment, which will not be repeated here.

[0063] In some embodiments of the present application, when the amine compound is selected from at least one of the following compounds, it is more conducive to the first reaction with the halogen-containing perfluoro resin, thereby improving the efficiency of the first reaction.

[0064]

[0065] Among them, o, p, q and w have the same meanings as in the first typical embodiment described above and are not repeated here.

[0066] In some embodiments of the present application, the halogen-containing perfluoro resin is mainly copolymerized by halogen-containing perfluoroolefin and tetrafluoroethylene; wherein the perfluoroolefin monomer structural formula is:

[0067] Wherein, Rf1 and X have the same meanings as above and are not described in detail here.

[0068] In some embodiments of the present application, the preparation reaction of the halogen-containing fluorine-containing perfluoro resin is schematically shown as follows:

[0069]

[0070] The above y is an integer between 0 and 3, such as 0, 1, 2 or 3; X is a halogen.

[0071] The method for preparing the halogen-containing perfluororesin by copolymerizing the halogen-containing perfluoroolefin and tetrafluoroethylene is not limited, and any method that can copolymerize the perfluoroolefin and tetrafluoroethylene is acceptable, preferably a free radical copolymerization reaction, which includes but is not limited to any one of solution polymerization, suspension polymerization, emulsion polymerization and bulk polymerization.

[0072] In some embodiments of the present application, halogen-containing perfluoroolefin and tetrafluoroethylene are used to prepare fluorine-containing perfluoro resin by solution polymerization. Specifically, the halogen-containing perfluoroolefin and tetrafluoroethylene are mixed in a solvent, and copolymerization reaction is carried out under the action of an initiator. Among them, the mass ratio of the total mass of the two monomers of halogen-containing perfluoroolefin and tetrafluoroethylene to the solvent is 1:5-15, and the type of solvent is not limited. Any type of solvent that can dissolve the above monomers can be used, preferably a fluorocarbon solvent or a fluorochloro solvent. Fluorocarbon solvents include but are not limited to any one or a mixed solution of at least two of perfluorocyclohexane, perfluoromethylcyclobutane or perfluorodimethylcyclobutane; fluorochloro solvents include but are not limited to 1,1,2-trifluoro-1,2,2-trifluoroethane, etc. The initiator is selected from any one or a combination of at least two of perfluoroperoxides, peroxides, azo compounds, persulfates and nitrogen difluoride (N2F2). Perfluoroperoxides include but are not limited to perfluoroalkyl acyl peroxides or perfluoroalkoxy acyl peroxides, such as perfluoropropionyl peroxide, perfluoroperoxyacetyl peroxide, etc. Persulfates include but are not limited to ammonium persulfate, alkali metal persulfides or alkaline earth metal persulfides, such as ammonium persulfate or potassium persulfate, etc. Peroxides include but are not limited to alkyl peroxide compounds or peroxydicarbonate compounds, such as tert-butyl peroxide, cumene peroxide hydroperoxide, diisopropyl peroxide or dicyclohexyl peroxydicarbonate, etc. Azo compounds include but are not limited to oil-soluble azo initiators or water-soluble azo compounds, such as azobisisobutyronitrile or azobisisobutylamine hydrochloride, etc.

[0073] In some typical embodiments of the present application, the fluorine-containing perfluororesin is prepared by solution polymerization, and the specific steps are:

[0074] Step A1, adding halogen-containing perfluoroolefin and tetrafluoroethylene in a molar ratio of 1-10:1-5 into a dry reactor, adding a solvent in a mass ratio of the sum of the mass of the two monomers to the mass of the solvent of 1:5-10, the solvent is selected from a fluorocarbon solvent or a fluorochloro solvent, and evacuating the reactor;

[0075] Step A2, heating the reactor to 20-120°C, adding an initiator, the initiator being selected from N2F2, perfluoroperoxide or azo initiator, and the concentration of the initiator being 0.1%-5%; adding the initiator in batches, adding the initiator once every half an hour, and adding it in 2-10 times; maintaining the reaction pressure at 0.1-10MPa, and reacting for 12-72h;

[0076] Step A3, after the reaction is completed, the pressure is released, and the unreacted monomers and solvents in the reaction are evaporated to obtain a powdery product. The product is extracted three times with methanol, and then the extracted product is dried at 100° C. for 8 hours to obtain a halogen-containing perfluoroolefin.

[0077] In some embodiments of the present application, halogen-containing perfluoroolefin and tetrafluoroethylene are used to prepare halogen-containing perfluoro resin by suspension polymerization. Specifically, the process includes dispersing perfluoroolefin and tetrafluoroethylene in an aqueous phase, and performing dispersion polymerization or suspension copolymerization under the action of a dispersant. The above-mentioned dispersant includes, but is not limited to, any one of perfluoroalkyl carboxylates, perfluoroalkoxy carboxylates, perfluoroalkyl sulfonates, perfluoroalkoxy sulfonates, triazine dispersants or perfluorocarboxylic acid ammonium salts, or a combination of at least two thereof. The type of initiator is the same as that of solution polymerization, which will not be described in detail here.

[0078] In some typical embodiments of the present application, the halogen-containing perfluoro resin is prepared by suspension polymerization, and the specific steps are:

[0079] Step B1, adding deionized water and a dispersant into a dry reactor, adding fluorinated perfluoroolefin and tetrafluoroethylene into the reactor in a molar ratio of 1-10:1-5, and evacuating the reactor, wherein the dispersant is selected from a perfluoroalkyl carboxylate, a perfluoroalkoxy carboxylate, a perfluoroalkyl sulfonate, a perfluoroalkoxy sulfonate or a triazine dispersant;

[0080] Step B2, heating the reactor to 20-120°C, adding an initiator, the initiator is selected from N2F2, perfluoroperoxide or azo initiator, the concentration of the initiator is 0.1%-5%, the initiator is added in batches, once every half an hour, and added in 2-10 times; maintaining the reaction pressure at 0.1-10MPa, and reacting for 1-24h;

[0081] Step B3, after the reaction is completed, the pressure is released to obtain a product system, and the unreacted monomers are separated and recovered from the product system to obtain a dispersion. The dispersion is condensed with a coagulant, and the obtained product is washed with trifluorotrichloroethane (abbreviated as F113) and dried at 100° C. for 8 hours to obtain a halogen-containing perfluoro resin, wherein the coagulant includes but is not limited to saturated salt water.

[0082] In some embodiments of the present application, a halogen-containing perfluoroolefin and tetrafluoroethylene are used to prepare a halogen-containing perfluoro resin by emulsion polymerization. Specifically, the perfluoroolefin and tetrafluoroethylene are dispersed in an aqueous phase, and emulsion polymerization is carried out under the action of an emulsifier and an initiator. The mass concentration of the emulsifier is preferably 0.1%-5%. The above-mentioned emulsifier includes but is not limited to ammonium perfluorooctanoate, sodium perfluorooctanoate; polyoxyethylene ether, such as any one or a combination of at least two of nonylphenol polyoxyethylene ether or polyoxyethylene fatty acid ether. The type of initiator is the same as solution polymerization, which will not be repeated here.

[0083] In some typical embodiments of the present application, the halogen-containing perfluoro resin is prepared by emulsion polymerization, and the specific steps are:

[0084] Step C1, adding deionized water and an emulsifier into a dry reactor, adding fluorinated perfluoroolefin and tetrafluoroethylene into the reactor in a molar ratio of 1-10:1-5, and evacuating the reactor, wherein the emulsifier is selected from ammonium perfluorooctanoate, sodium perfluorooctanoate; polyoxyethylene ether, such as any one of nonylphenol polyoxyethylene ether and polyoxyethylene fatty acid ether;

[0085] Step C2, heating the reactor to 20-120° C., adding an initiator, wherein the initiator is selected from persulfate, and the concentration of the initiator is 0.1%-10%. The initiator is added in batches, once every half an hour, and added in 2-10 times; maintaining the reaction pressure at 0.1-10 MPa, and reacting for 1-24 hours;

[0086] Step C3, after the reaction is completed, the pressure is released to obtain a product system, and the unreacted monomers are separated and recovered from the product system to obtain a dispersed solution. The dispersed solution is coagulated with a coagulant, and the obtained product is washed with water and / or ethanol and dried at 100° C. for 8 hours to obtain a halogen-containing perfluoro resin, wherein the coagulant is, for example, saturated salt water.

[0087] In some embodiments of the present application, the halogen-containing perfluoroolefin and tetrafluoroethylene are subjected to bulk polymerization to prepare the halogen-containing perfluoro resin. Specifically, the halogen-containing perfluoroolefin and tetrafluoroethylene are mixed and bulk polymerization is carried out using an initiator. The type of initiator is the same as that of solution polymerization and will not be described in detail here.

[0088] In some typical embodiments of the present application, the halogen-containing perfluoro resin is prepared by bulk polymerization, and the specific steps are:

[0089] Step D1, adding fluorinated perfluoroolefin and tetrafluoroethylene in a molar ratio of 1-10:1-5 into a dry reactor, and evacuating the reactor;

[0090] Step D2, heating the reactor to 20-120°C, adding an initiator, the initiator being selected from any one of N2F2, perfluoroperoxide, peroxide, and azo initiators, the concentration of the initiator being 0.1%-10%, the initiator being added in batches, once every half an hour, and added in 2-10 times; maintaining the reaction pressure at 0.1-10 MPa, and reacting for 1-24 hours;

[0091] Step D3, after the reaction is completed, the pressure is released to obtain a product system, and unreacted monomers are separated and recovered from the product system to obtain a solid resin.

[0092] In the above step S1, the molar ratio of -X group to amine compound in the halogen-containing perfluoro resin is preferably 1:5-10, so that the amine compound is in excess of the -X group, so as to further increase the substitution rate of the halogen-containing perfluoro resin. In particular, when the molar ratio of the two is 1:5-8, it is more conducive to increasing the grafting rate of the substitution rate of the halogen-containing perfluoro resin while reducing the amount of the amine compound, thereby reducing the preparation cost.

[0093] In some embodiments of the present application, the halogen-containing perfluoro resin and the amine compound are mixed in a first organic solvent to carry out a first reaction, so as to facilitate the full contact between the -X group in the halogen-containing perfluoro resin and the amine compound under the action of the first organic solvent, so that the substitution reaction proceeds more fully, and the substitution rate of the halogen-containing perfluoro resin is further improved.

[0094] The temperature of the first reaction is preferably 30-120° C., and the time is preferably 12-48 hours, so as to further improve the adequacy of the reaction between the amine compound and the -X group, thereby increasing the content of the ion exchange group in the ether-free perfluorinated ion exchange resin.

[0095] Typically but not limiting, the molar ratio of -X group to amine compound in the halogen-containing perfluoro resin is 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:12, 1:15 or 1:20; the temperature of the first reaction is 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C or 120°C; the time of the first reaction is 12h, 15h, 18h, 20h, 25h, 30h, 40h, 45h or 48h.

[0096] The type of the first organic solvent is not limited, and any organic solvent that can dissolve the halogen-containing perfluoro resin and the amine compound can be used, including but not limited to any one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide or ethyl acetate, or a mixed solution of at least two of them.

[0097] In order to further improve the efficiency of the first reaction, it is preferred that the first reaction is carried out under the action of a first acid binding agent, and the first reaction is promoted by adding the first acid binding agent into the first organic solvent.

[0098] The type of the first acid-binding agent is not limited, and any alkaline substance may be used. The alkaline substance includes but is not limited to any one of sodium hydroxide, sodium carbonate, sodium bicarbonate, cesium carbonate, lithium hydride or sodium hydride, or a combination of at least two thereof.

[0099] In the above step S2, the molar ratio of the amide group in the perfluoroamide resin to the dihalopentane is 1:5-10, so as to further improve the adequacy of the reaction between the amide group in the perfluoroamide resin and the dihalopentane. In particular, when the molar ratio of the two is 1:5-8, the amount of dihalopentane can be reduced while ensuring the adequacy of the reaction between the perfluoroamide resin and the dihalopentane, thereby reducing the preparation cost.

[0100] In some embodiments of the present application, the perfluoroamide resin and dihalopentane are mixed in a second organic solvent for a second reaction, so as to facilitate the full contact between the amide groups in the perfluoroamide resin and the dihalopentane under the action of the first organic solvent, so that the reaction between the two groups is more complete, and the content of the spirocyclic quaternary ammonium group in the ether-free perfluoro ion exchange resin is further increased, thereby further improving the ionic conductivity.

[0101] The temperature of the second reaction is preferably 30-80° C. and the time is preferably 12-48 hours, so as to further improve the efficiency of the quaternization reaction of the dihalopentane with the sulfonamide group.

[0102] Typically but not limiting, the temperature of the second reaction is 30°C, 40°C, 50°C, 60°C, 70°C or 80°C, and the time of the second reaction is 12h, 15h, 18h, 20h, 25h, 30h, 40h, 45h or 48h.

[0103] The type of the second organic solvent is not limited, and any organic solvent that can dissolve perfluoroamide resin and amine compounds can be used, including but not limited to any one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide or ethyl acetate, or a mixed solution of at least two of them.

[0104] In order to further improve the efficiency of the second reaction, it is preferred that the second reaction is carried out under the action of a second acid binding agent. The second reaction is promoted by adding the second acid binding agent into the second organic solvent.

[0105] The type of the second acid-binding agent is not limited, and any alkaline substance may be used. The alkaline substance includes but is not limited to any one of sodium hydroxide, sodium carbonate, sodium bicarbonate, cesium carbonate, lithium hydride or sodium hydride, or a combination of at least two thereof.

[0106] In some embodiments of the present application, the preparation method of the ether-free perfluoro ion exchange resin includes: (1) obtaining a bromine-containing perfluoro olefin and tetrafluoroethylene by free radical copolymerization; (2) performing a first reaction between the bromine-containing perfluoro resin and piperazine to obtain an amine-containing perfluoro resin; (3) performing a second reaction between the amine-containing perfluoro resin and 1,5-dibromopentane to obtain an ether-free perfluoro ion exchange resin. The reaction diagram is as follows:

[0107]

[0108] The meanings of m and n are the same as those described above and will not be repeated here.

[0109] In a third typical embodiment of the present application, an ion exchange membrane is also provided, the main material of which is any ether-bond-free perfluoro ion exchange resin provided in the first typical embodiment or an ether-bond-free perfluoro ion exchange resin prepared according to any preparation method provided in the second typical embodiment.

[0110] The main material of the ion exchange membrane provided in the present application is ether-free perfluorinated ion exchange resin, which has further improved alkali resistance and antioxidant properties, further extended service life, and can effectively promote the stable operation of the electrolytic cell.

[0111] In a fourth typical embodiment of the present application, application of the above-mentioned ion exchange membrane in the field of fuel cells is also provided.

[0112] The beneficial effects of the present application will be further illustrated below in conjunction with embodiments.

[0113] Example 1

[0114] The present application provides a perfluorinated ion exchange resin without an ether bond, which is prepared according to the following steps:

[0115] (1) The reactor was cleaned and dried, and 100 g (1 mol) of tetrafluoroethylene and 1890 g (the molar ratio of the two was 1:10) of 4-bromo-1,1,2-trifluoro-1-butene and 200 g of perfluoromethylcyclobutane (solvent) were added to the reactor. The reactor was evacuated and filled with nitrogen for three cycles. The temperature was raised to 60° C. and the pressure was raised to 3 MPa. 1.4 g of perfluoropropionyl peroxide initiator was weighed and dissolved in 40 g of perfluoromethylcyclobutane. The initiator was added to the reactor in batches every half an hour. After reacting for 4 hours, the reaction was stopped, the temperature was lowered, and the pressure was released. The material was poured out and transferred to a glass flask. The unreacted monomer and solvent were evaporated to obtain a powdery product. The product was further washed with methanol several times and dried at 100° C. for 12 hours to obtain 144.7 g of bromine-containing perfluoro resin. The molar content of bromine groups in the bromine-containing perfluoro resin was 0.28 mol.

[0116] (2) 144.7 g of the bromine-containing perfluororesin obtained in step (1) and 120 g of piperazine (the molar number of Br groups is recorded as N1, the molar number of piperazine is recorded as N2, and the molar ratio of the two is 1:5) are added to 500 mL of DMF (N,N-dimethylformamide), and 5 g of cesium carbonate is added at the same time. The mixture is reacted at 80° C. for 48 hours. After the reaction is completed, the mixture is filtered and the filter residue is washed to obtain 167.2 g of perfluoroamide resin. The molar content of secondary amine groups in the amine-containing perfluororesin is 0.27 mol.

[0117] (3) The amine-containing perfluororesin obtained in step (2) was added to 200 mL of DMSO (dimethyl sulfoxide) to react with 200 g of 1,5-dibromopentane, and cesium carbonate was added to increase the reaction rate. After the reaction was completed, the reaction was filtered and the filter residue was washed to obtain 187.2 g of ether-free perfluoroion exchange resin.

[0118] Example 2

[0119] The difference between this embodiment and embodiment 1 is that the following structural compound is used to replace piperazine:

[0120]

[0121] Example 3

[0122] The difference between this embodiment and embodiment 1 is that the following structural compound is used to replace piperazine:

[0123]

[0124] Example 4

[0125] The difference between this embodiment and embodiment 1 is that the following structural compound is used to replace piperazine:

[0126] Where o is 3.

[0127] Example 5

[0128] The difference between this embodiment and embodiment 1 is that the following structural compound is used to replace piperazine:

[0129] Where p is 2.

[0130] Example 6

[0131] The difference between this embodiment and embodiment 1 is that the following structural compound is used to replace piperazine:

[0132] Where q is 3.

[0133] Example 7

[0134] The difference between this embodiment and embodiment 1 is that the following structural compound is used to replace piperazine:

[0135] Where w is 1.

[0136] Test Example 1

[0137] The anion membranes prepared by the resins provided in the above examples under the same conditions were tested for ion conductivity using an electrochemical workstation, and the results are shown in Table 1 below:

[0138] Table 1

[0139] Ionic conductivity (mS / cm) Temperature 80°C, humidity 90% Example 1 103 Example 2 84 Example 3 92 Example 4 100 Example 5 98 Example 6 88 Example 7 96

[0140] Test Example 2

[0141] The resins provided in the examples were immersed in 80°C, 1 mol / L NaOH solutions, and the resins were taken out from the solutions, cleaned and dried after immersion times of 1 h, 5 h, 10 h, 20 h, 50 h, 100 h, 200 h, 400 h, 800 h and 1000 h, respectively. The quality retention rates were measured, and the results are shown in Table 2 below.

[0142] Table 2

[0143]

[0144]

[0145] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0146] The ion exchange resin provided by the present application has a main chain of a perfluorinated ether-free structure, which can effectively improve the alkali stability and oxidation stability of the resin, and the introduction of a spirocyclic quaternary ammonium salt group into the side chain can further improve the alkali stability of the resin and improve the ion conductivity. The ether-free ion exchange resin provided by the present invention has excellent alkali resistance and antioxidant properties, and the life of the ion exchange membrane formed by the ether-free ion exchange resin as the main material is effectively improved, which can further promote the stable operation of the electrolytic cell.

[0147] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An ether bond-free perfluoro anion exchange resin, characterized in that: The ether bond-free perfluoro anion exchange resin has the following formula (I): Formula (I); In the formula (I), Rf1 represents a direct bond, a C1-C20 straight chain or branched alkylene group, and the carbon atoms therein may be selectively substituted by O; m and n are each independently selected from integers between 1 and 200; and R has the following general formula (II): Formula (II); In the above formula (II), each R 1a , R 1b and R 1c Each independently represents hydrogen, C1-C20 straight or branched alkyl, C3-C20 cycloalkyl, C4-C20 cycloalkylalkyl, C4-C20 alkylcycloalkyl, -NO2, -OR A 、-COR A 、-COOR A 、-SR A 、-SO2R A or-CONR A R B , where R A and R B Each independently represents the following first group: any one of hydrogen, C1~C20 straight chain or straight chain alkyl, C3~C20 cycloalkyl, C4~C20 cycloalkylalkyl, C4~C20 alkylcycloalkyl, C6~C20 phenyl, C2~C20 heterocyclic group, and the carbon atoms in the first group can be selectively substituted by N, O, S; A represents *N*, *NR1B* or *C(R2)R3B*, wherein, B represents *N*R4, *S*, *O*, a group represented by formula (III) or a group represented by formula (IV): Formula (III); Formula (IV); Wherein, R1 and R3 each independently represent the following second group: a direct bond, a C1-C20 straight chain or branched alkylene group, a C3-C20 cycloalkylene group, a C4-C20 cycloalkylalkylene group, a C4-C20 alkylcycloalkylene group, and the carbon atoms in the second group may be selectively substituted by N, O, or S; R2, R4, each R 2a , R 2b , R 2c , R 2d , R 3a , R 3b , R 3c and R 3d Each independently selected from the following third groups: hydrogen, C1-C20 straight or branched alkyl, C3-C20 cycloalkyl, C4-C20 cycloalkylalkyl, C4-C20 alkylcycloalkyl, -NO2, -OR A 、-COR A 、-COOR A 、-SR A 、-SO2R A or-CONR A R B , and the carbon atoms in the third group can be selectively substituted by N, O, or S.

2. The ether bond-free perfluoro anion exchange resin according to claim 1, characterized in that: The Rf1 is a direct bond, a C1-C10 straight chain or branched chain alkylene group, and the carbon atoms therein may be selectively substituted by O.

3. The ether bond-free perfluoro anion exchange resin according to claim 1, characterized in that: In the formula (II), A represents *N*, *NR1B* or *C(R2)R3B*, and B represents *N*R4, *S*, *O*, a group represented by formula (III) or a group represented by formula (IV); Wherein, the R2, each R 1a , R 1b , R 1c , R 2a , R 2b , R 2c , R 2d , R 3a , R 3b , R 3c and R 3d Each independently represents hydrogen, methyl, ethyl, tert-butyl, -NO2, -OR A 、-COR A 、-COOR A 、-SR A 、-SO2R A or-CONR A R B , where R A and R B Each independently represents hydrogen, a C1~C10 straight chain or a straight-chain alkyl group; R1 and R3 each independently represent a direct bond, a C1~C10 straight chain or a straight-chain alkyl group, wherein the carbon atoms may be selectively substituted by O or S; and when R1 is a direct bond, B represents *N*R4, *S* or *O*; when R3 is a direct bond, B represents *N*R4, *S* or *O*.

4. The ether bond-free perfluoro anion exchange resin according to claim 1, characterized in that: The Rf1 is a direct bond, a C1-C6 straight chain or branched chain alkylene group, and the carbon atoms therein may be selectively substituted by O; The R is selected from at least one of the following compounds: ； wherein o, p, q and w are each independently selected from integers between 1 and 3.

5. A method for preparing a perfluoro anion exchange resin without an ether bond, characterized in that: The preparation method comprises: Step S1, mixing a halogen-containing perfluoro resin and an amine compound to perform a first reaction to obtain a perfluoroamide resin; Step S2, mixing the perfluoroamide resin with 1,5-dihalopentane to perform a second reaction to obtain the ether bond-free perfluoro anion resin; Wherein, in the step S1, the halogen-containing perfluoro resin has the following structure (V): Formula (V); In the above formula (V), Rf1, m, n have the same definitions as those in any one of claims 1 to 4, and X represents a halogen; In the step S2, the amine compound has a structure as shown in the following formula (VI): Formula (VI); In the above formula (VI), each R 1a , R 1b , R 1c It has the same definition as in any one of claims 1 to 4; D represents AH, and A has the same definition as in any one of claims 1 to 4.

6. The preparation method according to claim 5, characterized in that: The amine compound is selected from at least one of the following compounds: ； wherein o, p, q and w are each independently selected from integers between 1 and 3.

7. The preparation method according to claim 6, characterized in that: In the step S1, the halogen-containing perfluoro resin is mainly formed by copolymerization of halogen-containing perfluoroolefin and tetrafluoroethylene; Wherein, the halogen-containing perfluoroolefin structural formula is: ； Rf1 and X have the same meanings as described in claim 5.

8. The preparation method according to any one of claims 5 to 7, characterized in that: In the step S1, the molar ratio of the -X group in the halogen-containing perfluoro resin to the amine compound is 1:5-10.

9. The preparation method according to claim 8, characterized in that: In the step S1, the molar ratio of the -X group in the halogen-containing perfluoro resin to the amine compound is 1:5-8.

10. The preparation method according to any one of claims 5 to 7, characterized in that: The halogen-containing perfluoro resin and the amine compound are mixed in a first organic solvent to perform the first reaction. The temperature of the first reaction is 30-120° C., and the time of the first reaction is 12-48 hours.

11. The preparation method according to claim 10, characterized in that: The first reaction is carried out under the action of a first acid binding agent, and the first acid binding agent is added into the first organic solvent.

12. The preparation method according to claim 11, characterized in that: The first organic solvent includes at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide or ethyl acetate; And / or, the first acid binding agent is an alkaline substance, and the alkaline substance includes at least one of sodium hydroxide, sodium carbonate, sodium bicarbonate, cesium carbonate, lithium hydride or sodium hydride.

13. The preparation method according to any one of claims 5 to 7, characterized in that: In the step S2, the molar ratio of the amide group in the perfluoroamide resin to the dihalopentane is 1:5-10.

14. The preparation method according to claim 13, characterized in that: The perfluoroamide resin and the dihalopentane are mixed in a second organic solvent to carry out the second reaction. The temperature of the second reaction is 30-80° C. and the time of the second reaction is 12-48 hours.

15. The preparation method according to claim 14, characterized in that: The second reaction is carried out under the action of a second acid binding agent, and the second acid binding agent is added into the second organic solvent.

16. The preparation method according to claim 15, characterized in that: The second organic solvent includes at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide or ethyl acetate.

17. The preparation method according to claim 16, characterized in that: The second acid-binding agent is an alkaline substance, and the alkaline substance includes at least one of sodium hydroxide, sodium carbonate, sodium bicarbonate, cesium carbonate, lithium hydride or sodium hydride; And / or, the dihalopentane includes at least one of dichloropentane and dibromopentane.

18. An anion exchange membrane, characterized in that: The main material of the anion exchange membrane is the ether-bond-free perfluorinated ion exchange resin according to any one of claims 1 to 4 or the ether-bond-free perfluorinated ion exchange resin prepared by the preparation method according to any one of claims 5 to 17.

19. Use of the anion exchange membrane according to claim 18 in a fuel cell.

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