Polymer manufacturing method, polymer, electrolyte membrane, fuel cell, and electrolysis device

Abstract

To provide a method for producing a polymer that can give a high-molecular-weight polymer, a polymer obtainable by the production method, an electrolyte membrane that includes the polymer and has excellent chemical durability, and a fuel cell and an electrolysis device including the electrolyte membrane.SOLUTION: The present invention provides a method for producing a polymer including a constitutional unit represented by formula (1), the method including reacting a set of compounds having two specific structures in the presence of a specific catalyst, where, Ar1 is a group including an aromatic ring having an ion exchange group, and Ar2 is a group including an aromatic ring.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing a polymer, a polymer, an electrolyte membrane, a fuel cell, and an electrolysis device. [Background technology]

[0002] Electrolyte membranes and electrolyte ionomers are used in various fuel cells, such as polymer electrolyte fuel cells and solid alkaline fuel cells, as well as in various electrolysis technologies, such as water electrolysis. These electrolyte membranes are required to have excellent ionic conductivity and chemical and mechanical durability sufficient for long-term use. Furthermore, electrolyte ionomers are required to have high chemical durability and high fuel gas permeability.

[0003] In Patent Document 1, the present inventors disclose a proton-conducting material for an electrolyte membrane that has high swelling resistance, high proton conductivity, and a high density of ion-exchange groups, the proton-conducting material having a specific hydrophilic portion and a specific hydrophobic portion, and at least one of the hydrophilic portion and the hydrophobic portion has a repeating unit containing a specific cyclic compound. The proton-conducting material has a structure in which the hydrophilic portion and the hydrophobic portion are bonded via an ether bond. Proton-conducting materials having ether bonds in the main chain have the problem of degradation due to cleavage of the ether bonds, particularly in alkaline environments.

[0004] The present inventors have disclosed a polymer that does not contain an ether bond in the main chain and a method for producing the same in Patent Document 2. An electrolyte membrane using the polymer of Patent Document 2 is excellent in chemical durability and membrane strength. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-44242 [Patent Document 2] Patent Publication No. 2021-42351 Summary of the Invention [Problem to be solved by the invention]

[0006] A polymer with a relatively high molecular weight can be produced according to the polymer production method of Patent Document 2. On the other hand, the polymer of Patent Document 2 contains a relatively large number of fluorine atoms because a fluorine-substituted aromatic compound is used as a raw material. The present inventors have investigated a method for producing a polymer that does not contain fluorine atoms, taking into consideration polymer recycling and other factors from the perspective of SDGs and other goals. However, when the production process of Patent Document 2 was applied using an aromatic compound that does not contain fluorine atoms, only a polymer with a relatively small molecular weight was obtained. From the perspective of film strength and the like, it is necessary to produce a polymer with a high molecular weight.

[0007] The present invention aims to provide a method for producing a polymer that can produce a high-molecular-weight polymer, a polymer that can be produced by the method, an electrolyte membrane that uses the polymer and has excellent chemical durability, and a fuel cell and an electrolysis device that use the electrolyte membrane. [Means for solving the problem]

[0008] The method for producing a polymer according to the present invention comprises the steps of: A method for producing a polymer containing a constitutional unit represented by the following formula (1): A compound represented by the following formula (2A) and a compound represented by the following formula (3A), or A compound represented by the following formula (2B) and a compound represented by the following formula (3B): The reaction is carried out in the presence of a catalyst represented by the following formula (4): [ka] however, Ar 1 is a group containing an aromatic ring having an ion exchange group, Ar 2 is a group containing an aromatic ring, Ar 3is a group containing an aromatic ring having a functional group selected from a halogeno group, a sulfonate ester group, a phosphate ester group, a carboxylate ester group, an imidazole group, and an amino group, X 1 and X 2 are each independently Br or I, R 1 and R 2 are each independently -B(OH)2, -B(OR 11 )2, -BF3X 11 or a MIDA boronic acid ester, R 11 is an alkyl group which may have a substituent, and two R 11 may be linked to form a ring structure, X 11 is a monovalent cation, L is a phosphine ligand.

[0009] In one embodiment of the above production method, the reaction is carried out in the presence of a base.

[0010] In one embodiment of the above production method, the catalyst acts as L-PdCl during the reaction.

[0011] In one embodiment of the above production method, the phosphine ligand is one or more selected from the group consisting of tri-tert-butylphosphine, triphenylphosphine, tricyclohexylphosphine, and 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl.

[0012] The polymer according to the present invention contains a constitutional unit represented by the following formula (1) and has a weight-average molecular weight of 100,000 or more. [ka] however, Ar 1 is a group containing an aromatic ring having an ion exchange group, Ar 2 is a group containing an aromatic ring.

[0013] One embodiment of the polymer has no fluorine atoms.

[0014] The present invention provides an electrolyte membrane comprising the polymer according to the present invention. The present invention also provides a fuel cell and an electrolysis device comprising the electrolyte membrane according to the present invention. [Effects of the Invention]

[0015] The present invention provides a method for producing a polymer that results in a high-molecular-weight polymer, a polymer obtained by the production method, an electrolyte membrane that uses the polymer and has excellent chemical durability, and a fuel cell and an electrolysis device that use the electrolyte membrane. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a scheme showing an example of a method for producing a polymer. [Figure 2] 1 is a table and graph showing the evaluation results of swelling and ion conduction properties. [Figure 3] 1 shows NMR spectra showing the evaluation results of alkali durability. DETAILED DESCRIPTION OF THE INVENTION

[0017] The polymer, separation membrane, electrolyte membrane, fuel cell, and electrolysis device according to the present invention will be described in detail below. In the present invention, the term "polymer" includes "copolymer" unless otherwise specified. In the present invention, the term "ion exchange group" refers to a functional group that is dissociable and capable of ion exchange. In the present invention, the symbol "to" indicating a range of values ​​means that the values ​​before and after it are included as the lower and upper limits. In this specification, a "structural unit represented by formula (1)" may be referred to as a "structural unit (1)." This also applies to structural units represented by other formulas. In this specification, "a compound represented by formula (2A)" may be referred to as "compound (2A)." This also applies to compounds represented by other formulae, substituents, etc.

[0018] 1. Polymer manufacturing method and polymer The method for producing a polymer according to the present invention (hereinafter also referred to as the present production method) comprises: A method for producing a polymer containing a constitutional unit represented by the following formula (1): A compound represented by the following formula (2A) and a compound represented by the following formula (3A), or A compound represented by the following formula (2B) and a compound represented by the following formula (3B): The reaction is carried out in the presence of a catalyst represented by the following formula (4): [ka] however, Ar 1 is a group containing an aromatic ring having an ion exchange group, Ar 2 is a group containing an aromatic ring, Ar 3 is a group containing an aromatic ring having a functional group selected from a halogeno group, a sulfonate ester group, a phosphate ester group, a carboxylate ester group, an imidazole group, and an amino group, X 1 and X 2 are each independently Br or I, R 1 and R 2 are each independently -B(OH)2, -B(OR 11 )2, -BF3X 11 or a MIDA boronic acid ester, R 11 is an alkyl group which may have a substituent, and two R 11 may be linked to form a ring structure, X 11 is a monovalent cation, L is a phosphine ligand.

[0019] This production method is characterized by reacting an aryl halide, compound (2A) or compound (2B), with an organoboron compound, compound (3A) or compound (3B), in the presence of the catalyst (4). Use of the catalyst (4) makes it possible to produce a relatively high molecular weight polymer without using a fluorine-substituted aromatic compound as a raw material. According to this manufacturing method, for example, Ar 1 and Ar 2 and are arranged alternately, the polymer has no ether bond in the main chain, no fluorine atoms in the polymer, and has a weight average molecular weight of 100,000 or more. Each step of this manufacturing method will now be described.

[0020] Ar in the above formulas 1 is a group containing an aromatic ring having an ion exchange group as a substituent. 1 The polymer has excellent chemical durability and mechanical strength after film formation because it contains aromatic rings that form the polymer main chain. 1 The ion exchange groups contribute to the ionic conductivity of the polymer.

[0021] To impart proton conductivity to the polymer, the ion-exchange group preferably contains an acidic group, and the acidic group is preferably a sulfonic acid group (-SO3H group), a phosphoric acid group (-H2PO4 group), or a carboxylic acid group (-COOH group), with a sulfonic acid group being more preferred. Note that the H in the acidic group may be substituted with an alkali metal ion, alkaline earth metal ion, or the like. Furthermore, when anion conductivity is to be imparted to the present polymer, the ion exchange group preferably contains a quaternary ammonium group or an imidazolium group, and more preferably a quaternary ammonium group. Furthermore, from the viewpoint of alkali durability, the quaternary ammonium group is preferably a quaternary alkylammonium group. The quaternary alkylammonium group also includes those in which alkyl groups bonded to nitrogen atoms are bonded to each other to form a ring structure, and may be, for example, an azaadamantyl group or a quinuclidinium group. Preferred specific examples of the quaternary ammonium group include groups represented by the following formulae (e-1) to (e-8): Preferred specific examples of the imidazolium group include a group represented by the following formula (f-1), with a group represented by the following formula (f-2) or a group represented by the following formula (f-3) being more preferred.

[0022] [ka]

[0023] [ka] In the formula, R e are each independently a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, and R f are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or an aromatic group which may have a substituent, and A - is a monovalent or divalent or more anion, and R e or R f If there are multiple R e or R f may be the same or different. The wavy lines in the formula indicate Ar 1 The bond bonded to the aromatic ring in the figure is shown.

[0024] Above R e Specific examples of the alkyl group in the above R include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and a cyclohexyl group. f Specific examples of the alkyl group in R include a methyl group, an ethyl group, a propyl group, and a butyl group. f The aromatic group in the formula (I) may be a phenyl group or the like, and the substituent of the phenyl group may be an alkyl group having 1 to 6 carbon atoms or the like.

[0025] Above A - The anion is preferably an inorganic anion, and a chloride ion (Cl - ), bromide ion (Br -), iodide ion (I - ), bicarbonate ion (HCO3 - ), carbonate ions (CO3 2- ), hydroxide ion (OH - ) etc.

[0026] The ion exchange group is Ar 1 The ion-exchange group may be directly bonded to the aromatic ring in the ion-exchange group, or may further have a linking group and be bonded to the aromatic ring via the linking group. Here, the linking group represents an organic group that connects the acidic group, quaternary ammonium group, or imidazolium group of the ion-exchange group to the aromatic ring. The organic group is preferably a linear or branched alkylene group, and particularly preferably a linear alkylene group. The number of carbon atoms in the alkylene group can be appropriately adjusted depending on the physical properties required of the polymer. For example, by adjusting the carbon number of the alkylene group to 20 or less, preferably 16 or less, and more preferably 12 or less, the ion-exchange group capacity of the polymer is increased. On the other hand, by adjusting the carbon number of the alkylene group to 2 or more, preferably 4 or more, and more preferably 6 or more, the polymer can be obtained with excellent solubility and swelling resistance. Ar 1 The number of ion exchange groups in the polymer may be one or more, and is preferably one to two from the viewpoints of ion conductivity and polymer stability.

[0027] Ar 1 The aromatic ring in Ar forms part of the polymer backbone. 1 The presence of an aromatic ring gives the polymer excellent chemical durability and mechanical strength after film formation. The aromatic ring may be a benzene ring or a fused ring such as a naphthalene ring or an anthracene ring, or may be a heterocycle containing an oxygen atom (O), a nitrogen atom (N), or a sulfur atom (S) (e.g., thiophene, etc.), and may further be a structure in which these rings are linked via a single bond or a linking group. Examples of structures in which multiple rings are linked via single bonds include biphenyl, terphenyl, and fluorene. Examples of the linking group include linear or branched alkylene groups that may have a double bond, and specific examples include diphenylmethane, triphenylmethane, and stilbene.

[0028] Ar 1 In addition to the ion-exchange group, the aromatic ring in may further have a substituent other than the ion-exchange group. Examples of the substituent include an alkyl group having 1 to 20 carbon atoms which may have a substituent, and a phenyl group which may have a substituent. Specific examples of the alkyl group include alkyl groups such as methyl, ethyl, propyl, n-butyl, tert-butyl, pentyl, hexyl, and octyl, which may have a phenyl group as a substituent, etc. Furthermore, examples of the substituent that the phenyl group may have include alkyl groups having 1 to 6 carbon atoms.

[0029] The polymer is excellent in mechanical strength, chemical durability, and film-forming properties, and is therefore 1 is preferably a divalent aromatic group having an ion exchange group and optionally having a substituent other than the ion exchange group, and particularly preferably a group represented by any one of the following formulas (a-1) to (a-10): In addition, there are multiple Ar 1 may be the same as or different from each other.

[0030] [ka] In formulas (a-1) to (a-10), R aare each independently a hydrogen atom, an ion exchange group, or a substituent not having an ion exchange group, and there are a plurality of R a may be the same or different, and R a At least one of the groups is an ion exchange group. The wavy lines indicate Ar 2 indicates the bond bonded to

[0031] Ar in the above formulas 2 is a group containing an aromatic ring. 2 The aromatic ring in Ar forms part of the polymer backbone. 2 The presence of an aromatic ring gives the polymer excellent chemical durability and mechanical strength after film formation. Ar 2 The aromatic ring in 1 The aromatic rings in Ar 2 The aromatic ring in may have a substituent. The substituent is preferably a substituent other than an ion-exchange group. Examples of the substituent include an alkyl group having 1 to 20 carbon atoms which may have a substituent, and a phenyl group which may have a substituent. Specific examples of the alkyl group include alkyl groups such as methyl, ethyl, propyl, n-butyl, tert-butyl, pentyl, hexyl, and octyl, which may have a phenyl group as a substituent, etc. Furthermore, examples of the substituent that the phenyl group may have include alkyl groups having 1 to 6 carbon atoms.

[0032] The polymer is excellent in mechanical strength, chemical durability, and film-forming properties, and is therefore 2 is preferably a divalent aromatic group which may have a substituent other than an ion-exchange group, and particularly preferably a group represented by any one of the following formulas (b-1) to (b-10). In addition, there are multiple Ar 2 may be the same as or different from each other.

[0033] [ka] In formulas (b-1) to (b-10), R b are each independently a substituent that does not have a hydrogen atom or an ion exchange group, and there are a plurality of R b may be the same or different from each other. The wavy lines indicate Ar 1 , X 1 , X 2 or a bond bonded to B.

[0034] Ar 3 is Ar in the formula (1). 1 This corresponds to Ar 3 The functional group of Ar is converted into an ion exchange group in the conversion step described below. 3 The aromatic ring constituting the aromatic group in 1 The same can be mentioned. The Ar 3 is a group containing an aromatic ring having a functional group that can be converted into an ion-exchange group as a substituent. 3 The substituent may be a halogeno group, a sulfonate ester group (-SO3R 21 group), phosphate ester group (-R 21 2PO4 group), carboxylic acid ester group (-COOR 21 group), an imidazole group (see formula (h-1) below), or an amino group (—NRR′). where R 21 are each independently an organic group which may have a substituent. Examples of the organic group include an alkyl group and an aryl group. Examples of the substituent include an alkyl group having 1 to 20 carbon atoms which may have a substituent, and a phenyl group which may have a substituent.

[0035] [ka] wherein R, R', and R'' are each independently a hydrogen atom or an organic group.

[0036] In addition, R and R' in the amino group are each independently a hydrogen atom or an organic group. The organic group in the imidazole group and amino group includes the R 21 The organic group may be the same as the optionally substituted organic group in the above.

[0037] The functional group may be directly bonded to the aromatic ring, or may further have a linking group and be bonded to the aromatic ring via the linking group. 1 The same as Ar 3 The number of ion exchange groups in the polymer may be one or more, and is preferably one to two from the viewpoints of ion conductivity and polymer stability.

[0038] Ar 3 The aromatic ring in may have, in addition to the above functional groups, a substituent other than the above functional groups. 1 The substituents other than the ion exchange group in the above formula (I) are the same as those in the above formula (I).

[0039] The polymer is excellent in mechanical strength, chemical durability, and film-forming properties, and is therefore 3 is preferably one or more selected from the following formulae (c-1) to (c-10).

[0040] [ka] In formulas (c-1) to (c-10), R c are each independently a group having a functional group selected from a hydrogen atom, a halogeno group, a sulfonate ester group, a phosphate ester group, a carboxylate ester group, an imidazole group, and an amino group, or a substituent not having any of the above functional groups, and there are a plurality of R c may be the same or different, and R c At least one of the groups is the functional group. The wavy line is X 1 , X 2 or a bond bonded to B.

[0041] X 1 and X 2 are each independently Br (bromo group) or I (iodine group). Although not particularly limited, from the viewpoint of ease of synthesis of compound (2A) and compound (2B), X 1 and X 2 are preferably the same, and are more preferably bromo groups.

[0042] R in formula (3A) and formula (3B) 1 and R 2 is X in formula (2A) and formula (2B). 1 and X 2 R 1 and R 2 are each independently -B(OH)2 (boronic acid group), -B(OR 11 )2 (boronic ester group), -BF3X 11 (trifluoroborate salt), or MIDA boronate ester. 11 is an alkyl group which may have a substituent, and two R 11 may be linked to form a ring structure. 11 is a monovalent cation, such as an alkali metal ion. 1 and R 2 Specific examples of the formula (d-1) to the formula (d-5) below can be given, but are not limited to these. In addition, the formula (d-3) is a group consisting of two R 11 is an example of a ring structure, formula (d-4) is a boronic acid MIDA ester, and formula (d-5) is a trifluoroborate salt. 2 or Ar 3 It should be noted that, although not particularly limited, from the viewpoint of ease of synthesis of compounds (3A) and (3B), R 1 and R 2 are preferably the same.

[0043] [ka]

[0044] In this production method, the compound (2A) and the compound (3A), or the compound (2B) and the compound (3B), are reacted in the presence of a catalyst represented by the following formula (4): By using the catalyst (4), it is possible to synthesize a polymer having a weight-average molecular weight of 100,000 or more.

[0045] [ka]

[0046] The above L is a phosphine ligand, and among these, tri-tert-butylphosphine, triphenylphosphine, tricyclohexylphosphine, or 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl is preferred because it allows the production of a polymer with a high weight average molecular weight.

[0047] The method for synthesizing the catalyst (4) is not particularly limited. For example, the catalyst (4) can be obtained by mixing 2-aminobiphenyl and palladium(II) acetate, heating the mixture to cause a reaction, and then mixing and reacting the mixture with the ligand L and lithium chloride.

[0048] The reaction of the compound (2A) with the compound (3A), or the compound (2B) with the compound (3B), is usually carried out in a solvent such as tetrahydrofuran (THF), preferably in the presence of a base. The base is not particularly limited, but examples thereof include K2CO3, Na2CO3, KF, K3PO4, and K2HPO4. In the presence of a base, the catalyst (4) acts as L-PdCl. The reaction conditions can be appropriately adjusted depending on the molecular weight of the desired polymer. For example, a reaction temperature of around 60°C (e.g., 40 to 80°C) and a reaction time of 1 hour or longer can yield a polymer with a weight-average molecular weight of 100,000 or more.

[0049] Next, the Ar 3 The functional group is converted into an ion exchange group (conversion step). The conversion step may be carried out immediately after the above reaction or immediately before using the present polymer. The method for converting the functional group to an ion-exchange group can be appropriately selected depending on the functional group. For example, when the functional group is a halogeno group (e.g., -Cl), a quaternary ammonium group can be introduced by mixing with trimethylamine and heating. When the functional group is a sulfonate ester group, a phosphate ester group, or a carboxylate ester group, these groups can be converted to an ion-exchange group (sulfonate group, phosphate group, or carboxylate group) by hydrolysis.

[0050] According to the method for producing a polymer according to the present invention, it is possible to produce a polymer that contains a constitutional unit represented by the following formula (1) and has a weight-average molecular weight of 100,000 or more. [ka] However, Ar 1 is a group containing an aromatic ring having an ion exchange group, Ar 2 is a group containing an aromatic ring.

[0051] This polymer has no ether bond in the main chain, and therefore has excellent durability in alkaline environments. In addition, the main chain of this polymer can be made of all aromatic hydrocarbons, in which case it has even better chemical durability. This polymer has a weight-average molecular weight of 100,000 or more, and therefore the membranes produced using this polymer have excellent mechanical strength. In addition, this polymer has Ar 1 and Ar 2 Since the ion-exchange groups are distributed uniformly, this polymer can be suitably used for electrolyte membranes, etc. Furthermore, since this polymer does not contain fluorine atoms, it is easy to handle when disposing of or recycling after use. In addition, Ar in formula (1) 1 and Ar 2 The weight average molecular weight is determined by gel permeation chromatography (GPC) using standard polystyrene as the molecular weight.

[0052] 2. Electrolyte membrane The electrolyte membrane according to the present invention is characterized by containing the present polymer. Electrolyte membranes using the present polymer have excellent chemical durability, ionic conductivity, and membrane mechanical strength, and are suitable for use as electrolyte membranes for fuel cells and electrolysis devices. Furthermore, the present polymer, which has ion-exchange groups, can be easily dissolved in solvents (such as alcohols and mixed solvents of alcohol and water) commonly used in the preparation of membrane electrode assemblies (MEAs) for fuel cells, and has excellent gas permeability, making it suitable for use as an electrolyte ionomer in these batteries and electrolysis devices. This polymer has a high ionic conductivity (IEC) of 0.5 meq g -1 Over 4.0 meq·g -1 Furthermore, an electrolyte membrane using the polymer of the present invention has excellent swelling resistance, and the water content at 80°C is suppressed to 40% or less.

[0053] A general membrane-forming method can be applied to the method for producing the electrolyte membrane. For example, the present polymer is dissolved in a solvent in which it can be dissolved (e.g., dimethyl sulfoxide, alcohol, an alcohol aqueous solution, etc.) to prepare a polymer solution, which is then formed into a coating film using a known coating means, and dried to produce the electrolyte membrane.

[0054] In this polymer, by changing the ion exchange group to an acidic group, a proton-conductive electrolyte membrane can be obtained, and by changing the ion exchange group to a basic group such as the quaternary ammonium group, an anion-conductive electrolyte membrane can be obtained.

[0055] 3.Fuel cell The fuel cell according to the present invention is characterized by comprising the electrolyte membrane described above. The electrolyte membrane of the present invention can be suitably used in both solid alkaline fuel cells and polymer electrolyte fuel cells.

[0056] When the electrolyte membrane is applied to a solid alkaline fuel cell, an anion-conductive electrolyte membrane is used as the electrolyte membrane. The configuration of the solid alkaline fuel cell may be any known configuration. For example, a membrane electrode assembly is formed by disposing a cathode on one side of an electrolyte membrane and an anode on the other side, and oxygen is supplied to the cathode and fuel is supplied to the anode, and OH generated at the cathode is - The carbon monoxide moves through the electrolyte membrane to the anode, where it generates water, generating electricity. The fuel can be appropriately selected from conventionally known fuels, and examples thereof include, but are not limited to, hydrogen, methanol, ethanol, ethylene glycol, formate, hydrazine, sodium borohydride, ammonia, and the like. As a representative example, the reactions at each electrode when hydrogen, methanol, and formate are used as fuel are shown. -Hydrogen fuel cells Anode: 2OH - + H2 → 2H2O Cathode: O2+ 2H2O + 4e - → 4OH - Methanol fuel cells Anode: 6OH - + CH3OH → CO2+ 5H2O Cathode: O2+ 2H2O + 4e - → 4OH - Formate-based fuel cells Anode: HCOO - + 3OH - → 2H2O + CO3 2- + 2e - Cathode: O2+ 2H2O + 4e - → 4OH -

[0057] When the electrolyte polymer is applied to a polymer electrolyte fuel cell, a proton-conductive electrolyte membrane is used as the electrolyte membrane. The polymer electrolyte fuel cell may have a conventionally known configuration. For example, a membrane electrode assembly is formed by placing a cathode on one side of an electrolyte membrane and an anode on the other side, and oxygen is supplied to the cathode and fuel is supplied to the anode. Protons generated at the anode move to the anode via the electrolyte membrane, where they generate water, thereby generating electricity. The fuel can be appropriately selected from known fuels, and specific examples include the same fuels as those exemplified for the solid alkaline fuel cell. As a representative example, the reactions at each electrode when hydrogen is used as fuel are shown below. Anode: H2 → 2H + + 2e - Cathode: O2+ 4H + + 4e - → 2H2O

[0058] 4.Electrolyzer The electrolyte membrane of the present invention can be suitably used in water electrolysis and other electrolysis techniques (electrolysis methods), as well as in electrolysis devices that utilize these electrolysis methods. The electrolysis device can have, for example, an electrolytic cell containing the electrolyte membrane of the present invention, an anode, and a cathode, and can obtain a target substance by electrolyzing the target substance (oxidation-reduction reaction) via the electrolyte membrane of the present invention.

[0059] When the electrolyte membrane is applied to water electrolysis, a proton-conductive or anion-conductive electrolyte membrane is used. For example, an anode is placed on one side of a proton-conductive electrolyte membrane and a cathode on the other side, and protons generated at the anode are transferred to the cathode through the electrolyte membrane and combined with electrons at the cathode to produce hydrogen. The reaction formula at each electrode is as follows: Anode: 2H2O → O2+ 4H + + 4e - Cathode: 2H + + 2e - → H2

[0060] Another electrolysis technology is the electrolysis of carbon dioxide to produce formic acid. For example, protons produced at the anode are transferred to the cathode through an electrolyte membrane, where they react with carbon dioxide supplied to the cathode to produce formic acid. The reaction formula at each electrode is as follows: Anode: 2H2O → O2+ 4H + + 4e - Cathode: CO2+ 2H + + 2e - → HCOOH [Example]

[0061] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0062] Example 1: Polymer Production The polymer was synthesized according to Scheme 1 shown in Figure 1. The following description will be given with reference to the symbols in Scheme 1 (such as (i)) as appropriate.

[0063] <Step (i): Synthesis of Compound 1> [ka]

[0064] n-Tetrabutylammonium bromide (648 mg) was added to a two-necked flask with a solution of sodium hydroxide (150 g) in water (300 mL) and stirred under nitrogen. Separately, 2,7-dibromofluorene (4.86 g, 15 mmol) was dissolved in 1-bromohexane (24.8 g, 150 mmol) while heating, and this solution was added to the two-necked flask via syringe. After reacting at 85°C under nitrogen for 60 minutes, the solution was cooled to room temperature. The organic layer was extracted with dichloromethane (300 mL) and washed with 1 M hydrochloric acid (5 mL) and water (200 mL x 2). The dichloromethane was evaporated in an evaporator, and unreacted 1-bromohexane was removed under vacuum at 90°C. The resulting residue was applied to a silica gel column (eluent: hexane) to obtain the target compound 1 (6.50 g, 13.2 mmol). (Compound 1 1 H-NMR spectrum) 1 H-NMR (400 MHz, CDCl3): δ 7.51 (2H, d), δ 7.45 (4H, m), δ 1.91 (4H, m), δ 1.12 (4H, m), δ 1.05 (8H, m), δ 0.78 (6H, t),δ 0.59 (4H, m)

[0065] <Step (ii): Synthesis of Compound 2> [ka]

[0066] The above compound 1 (4.92 g, 10 mmol), bis-pinacolatodiborane (5.59 g, 22 mmol), potassium acetate (5.89 g, 60 mmol), and [1,1'-Bis(diphenylphosphino)ferrocene]palladium(II) dichloromethane adduct (408 mg, 0.5 mmol) were added to a two-necked recovery flask, which was then evacuated and purged with nitrogen. Dimethyl sulfoxide (100 mL) was added via syringe and the mixture was allowed to react under nitrogen at 90 °C for 6 hours. After cooling to room temperature, the organic layer was extracted with chloroform (200 mL) and washed with water (150 mL x 3). The chloroform was removed using an evaporator, and the residue was loaded onto a silica gel column (developing solvent: hexane:chloroform = 7:3) to obtain the desired compound 2 (3.75 g, 6.4 mmol). (Compound 2 1 H-NMR spectrum) 1 H-NMR (400 MHz, CDCl3): δ 7.80 (2H, d), δ 7.73 (4H, m), δ 1.99 (4H,m), δ 1.39 (24H, s),δ 1.08 (4H, m), δ 1.02 (8H, m), δ 0.80 (6H, t),δ 0.55 (4H, m)

[0067] <Step (iii): Synthesis of Compound 3> [ka]

[0068] A two-neck flask was charged with n-tetrabutylammonium chloride (417 mg) and a solution of sodium hydroxide (150 g) in water (300 mL) and stirred under nitrogen. Separately, 2,7-dibromofluorene (4.86 g, 15 mmol) was dissolved in 1,6-dichlorohexane (23.3 g, 150 mmol) while heating, and this solution was added to the two-neck flask via syringe. After reacting at 85°C under nitrogen for 60 minutes, the solution was cooled to room temperature. The organic layer was extracted with dichloromethane (300 mL) and washed with 1 M hydrochloric acid (50 mL) and water (200 mL x 2). The dichloromethane was evaporated in an evaporator, and unreacted 1,6-dichlorohexane was removed under vacuum at 90°C. The resulting residue was applied to a silica gel column (eluent: hexane) to obtain the desired compound 3 (6.50 g, 13.2 mmol). (Compound 3 1 H-NMR spectrum) 1 H-NMR (400 MHz, CDCl3): δ 7.52 (2H, d), δ 7.47-7.43 (4H, m), δ 3.42 (4H, t), δ 1.93 (4H,m), δ 1.60 (4H, m), δ 1.19 (4H, m), δ 1.08 (4H, m), δ 0.58 (4H, m)

[0069] <Step (iV): Synthesis of Polymer 1 (PFO-Cl)> [ka]

[0070] The above compound 2 (1173 mg, 2 mmol), the above compound 3 (1121 mg, 2 mmol), and P(t-Bu3)Pd-G2 catalyst (catalyst represented by compound (4), L is tri-tert-butylphosphine, Sigma-Aldrich, 20.5 mg, 4 mmol) were added to a two-necked flask, which was then evacuated and purged with nitrogen. Tetrahydrofuran (20 ml) and 10 M aqueous potassium phosphate solution (2 ml) were added via syringe, and the reaction was carried out at 60°C under nitrogen for 6 hours. The reaction solution was extracted with chloroform (100 ml) and washed with water (50 ml x 3). The chloroform was removed using a rotary evaporator, and the resulting residue was reprecipitated in methanol. The precipitate was filtered and then dried under vacuum to obtain the target polymer 1 (1.19 g). (GPC measurement results for polymer 1) GPC(CHCl3):Mn=46000,Mw=123000,Mw / Mn=2.67 Here, Mn is the number average molecular weight, and Mw is the weight average molecular weight.

[0071] <Step (V): Synthesis of Polymer 2 (PFO-C6-TMA)> [ka]

[0072] In a 50 ml vial, the polymer 1 (500 mg) was dissolved in chlorobenzene (20 ml), and 3.2 M trimethylamine methanol solution (1 ml) was added. The vial was then capped and reacted at 105 °C for 12 hours. After the solution was cooled to room temperature, dimethyl sulfoxide solution (20 ml) and 3.2 M trimethylamine methanol solution (1 ml) were added. The vial was then capped again and reacted at 105 °C for 12 hours. After cooling to room temperature, the reaction solution was transferred to a 100 ml recovery flask and concentrated using an evaporator to remove chlorobenzene. Dimethyl sulfoxide (30 ml) and 3.2 M trimethylamine methanol solution (1 ml) were added to the residue and reacted at 105 °C for 6 hours. After cooling to room temperature, the reaction solution was transferred to a 100 ml recovery flask and completely dried using an evaporator. The dried solid was washed with water, collected by filtration, and vacuum dried to obtain the target polymer 2 (505 mg). (Polymer 2 1 H-NMR spectrum) 1 H-NMR (400 MHz, CD3OD): δ 7.94 (4H, br), δ 7.78 (8H, br), δ 3.24 (4H, br), δ 3.05 (18H,s), δ 2.2 (8H,br),δ 1.64 (8H, br), δ 1.17 (16H, br), δ 0.82 (14H, br)

[0073] [Comparative Example 1] As a comparative example, the following polymer (PPO-TMA) was prepared. [ka] In addition, n and m indicate repeating units.

[0074] <Evaluation> [Electrolyte membrane manufacturing] Each of Polymer 2 of Example 1 and the polymer of Comparative Example 1 was dissolved in dimethyl sulfoxide to prepare a solution (20 mg / ml). Each of the solutions was cast onto a glass substrate and dried by heating at 100°C to form a film. The substrate was then immersed in water to peel the polymer film from the substrate, and after washing with pure water at 80°C, an electrolyte membrane with a thickness of 25 μm was obtained.

[0075] [Swelling and ionic conductivity evaluation] The ionic conductivity of each electrolyte membrane was measured. The ionic conductivity was calculated from the electrical resistance measured by AC impedance measurement. Platinum electrodes were used for in-plane AC impedance measurement, and the four-terminal method was used. The electrode distance for measuring voltage was 5 to 15 mm. The high-current and high-voltage electrodes were in contact with the low-current and low-voltage electrodes on the opposite side of the electrolyte membrane. The electrolyte membrane, along with the platinum electrodes, was sandwiched between two pairs of high-density polyethylene substrates, and the edges were fixed with screws. The electrolyte membrane was placed in a constant-temperature chamber (Espec SH-241 Bench-Top Type Temperature & Humidity Chamber) and allowed to stabilize for at least 3 hours at a constant temperature (40°C to 80°C) and humidity of 100 RH. Measurements were then performed. The AC impedance was measured using a Solartron 1260 (manufactured by Solartron, UK) under the conditions of an AC amplitude of 10-100mV and a frequency sweep from 1,000,000Hz to 1Hz. The measurement results are shown in the graph in Figure 2. Furthermore, for each of the electrolyte membranes, the ionic functional group capacity (IEC), the water content at 25° C. and 80° C., and the dimensional change rate due to water content were measured. The results are shown in the table of FIG.

[0076] The electrolyte membrane obtained from Polymer 2 of Example 1 exhibited good swelling resistance and excellent ionic conductivity compared to the electrolyte membrane of Comparative Example 1 having the same IEC.

[0077] [Chemical durability evaluation] The polymer 2 of Example 1 was immersed in an 8M NaOH aqueous solution maintained at 80°C for one week. 1 The H-NMR spectrum is shown in Figure 3. Figure 3 is a superposition of the spectra before and after immersion, and there was no change in the peaks derived from hydrogen atoms indicated by a and b in Figure 3, demonstrating that the material is stable to alkali.

[0078] As described above, according to the method for producing a polymer of the present invention, it is possible to obtain a polymer that does not contain fluorine atoms or ether bonds within the polymer and has a weight-average molecular weight of 100,000 or more. It has been shown that the polymer has good film formability, exhibits excellent ionic conductivity, and is excellent in swelling resistance and chemical durability.

Claims

1. A method for producing a polymer containing a constitutional unit represented by the following formula (1): A compound represented by the following formula (2A) and a compound represented by the following formula (3A), or A compound represented by the following formula (2B) and a compound represented by the following formula (3B): A method for producing a polymer, comprising reacting in the presence of a catalyst represented by the following formula (4): 【Chemistry 1】 however, Ar １ is a group represented by any one of the following formulas (a-1) to (a-10): Ar ２ is a group represented by any one of the following formulas (b-1) to (b-10), Ar ３ is a group containing an aromatic ring having a functional group selected from a halogeno group, a sulfonate ester group, a phosphate ester group, a carboxylate ester group, an imidazole group, and an amino group, X １ and X ２ are each independently Br or I; R １ and R ２ are each independently -B(OH) ２ , -B(OR １１ ) ２ , -BF ３ X １１ or a boronic acid MIDA ester, R １１ is an alkyl group which may have a substituent, and two R １１ may be linked to form a ring structure, X １１ is a monovalent cation, L is one or more phosphine ligands selected from tri-tert-butylphosphine, triphenylphosphine, tricyclohexylphosphine, and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl. 【Chemistry 2】 R ａ are each independently a hydrogen atom, an ion exchange group, or a substituent not having an ion exchange group, and a plurality of R ａ may be the same or different, at least one of Ra is an ion exchange group, and the wavy line represents a bond bonding to Ar 2 . 【Transformation 3】 R ｂ are each independently a substituent not having a hydrogen atom or an ion exchange group, and a plurality of R ｂ may be the same or different, and the wavy line represents a bond bonded to Ar 1 , X 1 , X 2 or B.

2. The method for producing a polymer according to claim 1 , wherein the reaction is carried out in the presence of a base.

3. The method for producing a polymer according to claim 1 or 2, wherein the catalyst acts as L-PdCl during the reaction.

4. A method for producing a polymer described in any one of claims 1 to 3, which produces a polymer containing a structural unit represented by formula (1) and having a weight average molecular weight of 100,000 or more.

5. The method for producing a polymer according to claim 4 , wherein the produced polymer does not contain fluorine atoms.

6. A method for producing an electrolyte membrane, comprising a method for producing a polymer described in any one of claims 1 to 5.

7. A method for producing a fuel cell, comprising the method for producing the electrolyte membrane according to claim 6.

8. A method for producing an electrolysis device, comprising the method for producing the electrolyte membrane according to claim 6.

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