Method for producing sulfonic acid ester, method for producing fluorosulfonyl group-containing compound, method for producing polymer, method for producing liquid composition, method for producing membrane, method for producing membrane electrode assembly, and compound

Abstract

The present invention provides: a method for producing a sulfonic acid ester, with which it is possible to produce a sulfonic acid ester with a high yield; a method for producing a fluorosulfonyl group-containing compound; a method for producing a polymer; a method for producing a liquid composition; a method for producing a membrane; a method for producing a membrane electrode assembly; and a compound. The membrane and the membrane electrode assembly can be used, for example, in fuel cells and PEM water electrolysis applications.　With the method for producing a sulfonic acid ester according to the present invention, a compound represented by formula (3) is obtained by reacting a compound represented by formula (1) with a compound represented by formula (2). In formulae (1) to (3), R is an n-valent aliphatic hydrocarbon group which may have an aromatic hydrocarbon group as a substituent, and the aliphatic hydrocarbon group may have an etheric oxygen atom or -CO- between carbon atom-carbon atom bonds. Z+ is a monovalent cation, n is a number of 1 to 4, X is a hydrogen atom or a halogen atom, and Y is a monovalent leaving group. (1): R-(SO2O-Z+)n, (2): CFX=CF-CF2-Y, (3): R-(SO2O-CFX-CF=CF2)n

Description

Methods for producing sulfonic acid esters, methods for producing fluorosulfonyl group-containing compounds, methods for producing polymers, methods for producing liquid compositions, methods for producing membranes, methods for producing membrane electrode assemblies, and compounds

[0001] The present invention relates to a method for producing sulfonic acid esters, a method for producing fluorosulfonyl group-containing compounds, a method for producing polymers, a method for producing liquid compositions, a method for producing membranes, a method for producing membrane electrode assemblies, and compounds.

[0002] Sulfonic acid esters are used in a variety of applications, for example, as raw materials for compounds containing fluorosulfonyl groups. Fluorosulfonyl group-containing compounds are also sometimes used as raw materials for polymers containing sulfonic acid groups. Polymers containing sulfonic acid groups are used, for example, in the manufacture of catalyst layers and electrolyte membranes in membrane electrode assemblies for polymer electrolyte fuel cells. Another application of sulfonic acid esters is as surfactants. For example, Patent Document 1 describes a method for producing sulfonic acid esters used as surfactants, specifically Rf １ C(COOM)Rf ２ SO ３ H (wherein M is a hydrogen atom, etc., Rf １ and Rf １ A method is disclosed for reacting a compound represented by (where represents a fluoroalkyl group, etc.) with vinylidene fluoride under acidic conditions.

[0003] Japanese Patent Publication No. 2009-29722

[0004] As mentioned above, Patent Document 1 describes a method for producing sulfonic acid esters, but there is a need for new methods for producing sulfonic acid esters other than the method described in Patent Document 1.

[0005] The present invention has been made in view of the above problems and aims to provide a method for producing sulfonic acid esters that can produce sulfonic acid esters in good yield. The present invention also aims to provide a method for producing fluorosulfonyl group-containing compounds, a method for producing polymers, a method for producing liquid compositions, a method for producing membranes, a method for producing membrane electrode assemblies, and compounds.

[0006] The present inventors have found that the above problems can be solved by the following configuration. [1] A method for producing a sulfonic acid ester, comprising reacting a compound represented by formula (1) with a compound represented by formula (2) to obtain a compound represented by formula (3). R-(SO ２ O － Z ＋ ) ｎ (1) CFX = CF - CF ２ -Y (2) R-(SO ２ O - CFX - CF = CF ２ ) ｎ (3) In formula (1), formula (2) and formula (3), R is an n-valent aliphatic hydrocarbon group which may have an aromatic hydrocarbon group as a substituent. The above aliphatic hydrocarbon group may have an etheric oxygen atom or -CO- between carbon atom-carbon atom bonds. Z ＋ is a monovalent cation. n is an integer of 1 to 4. X is a hydrogen atom or a halogen atom. Y is a monovalent leaving group. [2] In the above formula (1) and the above formula (3), R is a group represented by -(CH ２ ) ｍ１ -CO-(CH ２ )<0000{\018}-, n is 2, The method for producing a sulfonic acid ester according to [1]. In the above formula, m1 and m2 are each independently an integer of 1 to 3. [3] In the above formula (1), the above formula (2) and the above formula (3), R is -CH ２ -CO-CH ２ -, n is 2, X is a fluorine atom, Y is -OSO ２ F, The method for producing a sulfonic acid ester according to [1]. [4] Before reacting the compound represented by formula (1) with the compound represented by formula (2), a compound represented by formula (1A) is mixed with a base or a salt to obtain the compound represented by formula (1). The method for producing a sulfonic acid ester according to any one of [1] to [3]. R-(SO ２ OH) ｎ(1A) In formula (1A), R and n are the same as R and n in formula (1) above. [5] A method for producing a fluorosulfonyl group-containing compound, characterized by obtaining a compound represented by formula (3) above by the manufacturing method described in any of [1] to [4], and reacting the compound represented by formula (3) above with an alkali metal fluoride to obtain a compound represented by formula (5). R-(SO ２ F) ｎ (5) In formula (5), R and n are the same as R and n in formula (3) above. [6] A method for producing a fluorosulfonyl group-containing compound, characterized by obtaining a compound represented by formula (3) above by the manufacturing method described in [2], reacting the compound represented by formula (3) above with an alkali metal fluoride to obtain a compound represented by formula (5B), fluorinating the compound represented by formula (5B) above to obtain a compound represented by formula (6B), and reacting the compound represented by formula (6B) above with a compound represented by formula (2B) to obtain a compound represented by formula (7B). FSO ２ - (CH ２ ) ｍ１ -CO-(CH ２ ) ｍ２ -SO ２ F (5B) FSO ２ - (CF ２ ) ｍ１ -CO-(CF ２ ) ｍ２ -SO ２ F (6B) CF ２ = CF - CF ２ - OSO ２ F Formula (2B) CF ２ = CF - CF ２ -O-CF[(CF ２ ) ｍ１ -SO ２ F] [(CF ２ ) ｍ２ -SO ２F] (7B) In formulas (5B), (6B), and (7B), m1 and m2 are each independently integers from 1 to 3. [7] A method for producing a fluorosulfonyl group-containing compound according to [6], wherein m1 and m2 are 1 in formulas (5B), (6B), and (7B). [8] A method for producing a polymer, characterized by obtaining a compound represented by formula (7B) by the production method described in [6], and polymerizing a monomer containing the compound represented by formula (7B) to obtain a polymer having units based on the compound represented by formula (7B). [9] A method for producing a polymer according to [8], wherein m1 and m2 are each 1 in formula (7B).

[10] A method for producing a polymer according to [8], wherein a polymer having units based on the compound represented by formula (7B) is subjected to hydrolysis to obtain a polymer having units represented by formula (8B) described later. In formula (8B) described later, m1 and m2 are each the same as m1 and m2 in formula (7B).

[11] The method for producing a polymer according to

[10] , wherein in formula (8B), m1 and m2 are each 1.

[12] The method for producing a liquid composition, characterized by obtaining a polymer having units represented by formula (8B) by the method for producing

[10] or

[11] , and mixing the polymer having units represented by formula (8B) with a liquid medium to obtain a liquid composition.

[13] The method for producing a film, characterized by obtaining the liquid composition by the method for producing

[12] , and using the liquid composition to obtain a film.

[14] The method for producing a membrane electrode assembly having an anode having a catalyst layer, a cathode having a catalyst layer, and a solid polymer electrolyte membrane disposed between the anode and the cathode, characterized by obtaining the liquid composition by the method for producing

[12] , mixing the liquid composition with a catalyst to obtain a catalyst layer forming composition, and using the catalyst layer forming composition to obtain a catalyst layer for at least one of the anode and the cathode.

[15] A compound represented by formula (3). R-(SO ２ O-CFX-CF=CF ２ ) ｎ(3) In formula (3), R is an n-valent aliphatic hydrocarbon group which may have an aromatic hydrocarbon group as a substituent. The aliphatic hydrocarbon group may have an etheric oxygen atom or -CO- between the carbon-carbon bonds. n is an integer from 1 to 4. X is a hydrogen atom or a halogen atom.

[16] In the above formula (3), R is -(CH ２ ) ｍ１ -CO-(CH ２ ) ｍ２ A compound according to

[15] , wherein the group is represented by - and n is 2. In the above formula, m1 and m2 are each independently integers from 1 to 3.

[17] In the above formula (3), R is -CH ２ -CO-CH ２ The compound described in

[15] , wherein n is 2.

[0007] The present invention provides a method for producing sulfonic acid esters in high yield. Furthermore, the present invention also provides a method for producing fluorosulfonyl group-containing compounds, a method for producing polymers, a method for producing liquid compositions, a method for producing membranes, a method for producing membrane electrode assemblies, and compounds.

[0008] The following definitions of terms apply throughout this specification and the claims unless otherwise specified. A compound represented by formula (1) is referred to as "compound 1". Compounds represented by other formulas are referred to similarly. A unit represented by formula (7B-1) is referred to as "unit 7B-1". Units represented by other formulas are referred to similarly.

[0009] In polymers, a "unit" refers to an atomic group derived from one monomer molecule, formed by the polymerization of monomers. A unit may be an atomic group directly formed by a polymerization reaction, or it may be an atomic group in which a portion of the atomic group is converted to a different structure by processing the polymer obtained by the polymerization reaction.

[0010] "Sulfonic acid group" is a general term for salt-type sulfonic acid groups and acid-type sulfonic acid groups. In this specification, when "sulfonic acid group" is used without specifying whether it is salt-type or acid-type, it refers to the general term described above. -SO ３－ Z ＋ (However, Z ＋ H ＋ It refers to a group represented by (-SO₄). "Salt-type sulfonic acid group" refers to a salt-type sulfonic acid group (-SO₄). ３ － M ＋ However, M ＋ This refers to a metal ion or ammonium ion. "Acid-type sulfonic acid group" means an acid-type sulfonic acid group (-SO ３ － H ＋ ) means.

[0011] Numerical ranges expressed using "~" mean a range that includes the numbers written before and after "~" as the lower and upper limits. In numerical ranges described stepwise in this specification, the upper or lower limit stated in one numerical range may be replaced with the upper or lower limit of another numerical range described stepwise. Also, in numerical ranges described in this specification, the upper or lower limit stated in one numerical range may be replaced with the values ​​shown in the examples.

[0012] [Method for Producing Sulfonic Acid Esters] The method for producing sulfonic acid esters of the present invention includes a step of reacting compound 1 and compound 2 to obtain compound 3 (hereinafter also referred to as "step 1"). The method for producing sulfonic acid esters of the present invention allows for the simple production of sulfonic acid esters in high yield.

[0013] The present invention's method for producing sulfonic acid esters preferably further includes a step (hereinafter also referred to as "step 0") before step 1, in which compound 1A (described later) is mixed with a base or salt to obtain compound 1.

[0014] In the following sections, each compound will be described, followed by a description of each step.

[0015] <Compound 1> Compound 1 used in step 1 is the compound represented by the following formula (1): R-(SO ２ O － Z ＋ ) ｎ (1)

[0016] In formula (1), R is an n-valent aliphatic hydrocarbon group which may have an aromatic hydrocarbon group as a substituent. Here, the aliphatic hydrocarbon group may have an etheric oxygen atom or -CO- between the carbon atoms. The aliphatic hydrocarbon group in R may be linear, branched, or cyclic. The number of carbon atoms in the aliphatic hydrocarbon group in R is preferably 1 or more, more preferably 2 or more, preferably 20 or less, and more preferably 10 or less. The aliphatic hydrocarbon group in R is preferably a divalent aliphatic hydrocarbon group, specifically an alkylene group, an alkenylene group, or an alkylene group. Among these, from the viewpoint of suppressing side reactions and increasing the yield of the target product, the alkylene group or alkenylene group is preferred, and the alkylene group is more preferred. The aliphatic hydrocarbon group in R may have an etheric oxygen atom or -CO- between the carbon atoms, and it is preferable that it has -CO- between the carbon atoms. R may have an aromatic hydrocarbon group as a substituent. In other words, the hydrogen atoms of the divalent aliphatic hydrocarbon group may be substituted with a monovalent aromatic hydrocarbon group. The aromatic hydrocarbon group may further have substituents. Examples of aromatic hydrocarbon groups include C6 to C18 aromatic hydrocarbon groups such as phenyl, tolyl, xylyl, and naphthyl groups.

[0017] In formula (1), Z ＋ Z is a monovalent cation. ＋ Examples of monovalent cations in this formula include potassium ions, sodium ions, cesium ions, pyridinium, ammonium, tetrabutylammonium, and imidazolium. From the viewpoint of reactivity with compound 2, pyridinium, tetrabutylammonium, and imidazolium are preferred, and pyridinium is more preferred. In formula (1), n ​​is an integer from 1 to 4, preferably 2 or 3, and more preferably 2.

[0018] (Compound 1B and Compound 1C) Compound 1, in its reaction with Compound 2, suppresses side reactions and increases the yield of the target product, and in formula (1), R is -(CH ２ ) ｍ１ -CO-(CH２ ) ｍ２ -represents a group, and compound 1B where n is 2 is preferred, and R is -CH ２ -CO-CH ２ -represents a group, and compound 1C where n is 2 is more preferred.

[0019] (Z ＋ ) － OSO ２ -(CH ２ ) ｍ１ -CO-(CH ２ ) ｍ２ -SO ２ O － (Z ＋ ) (1B) (Z ＋ ) － OSO ２ -CH ２ -CO-CH ２ -SO ２ O － (Z ＋ ) (1C)

[0020] In formula (1B) and formula (1C), Z ＋ is synonymous with Z ＋ in formula (1). In formula (1B), m1 and m2 are each independently an integer of 1 to 3, preferably an integer of 1 to 2, and more preferably 1.

[0021] <Compound 2> Compound 2 used in Step 1 is a compound represented by the following formula (2). CFX = CF - CF ２ -Y (2) <000035​​​​​​​​​​​​​​​​​​​Preferably, -OSO ２ F is preferable.

[0023] (Compound 2B) Compound 2 is formulated such that, from the viewpoint of increasing the reaction rate with compound 1, X in formula (2) is a fluorine atom and Y is -OSO ２ Compound 2B, which is F, is preferred. CF ２ = CF - CF ２ - OSO ２ F (2B)

[0024] <Compound 3> Compound 3 obtained by step 1 is a compound (sulfonic acid ester) represented by the following formula (3).

[0025] R-(SO ２ O-CFX-CF=CF ２ ) ｎ (3)

[0026] In equation (3), R and X are the same as R in equation (1) and X in equation (2), respectively. In equation (3), n is an integer from 1 to 4, preferably 2 or 3, and more preferably 2.

[0027] (Compound 3B and Compound 3C) Compound 3 is a compound in which R is -(CH) in formula (3). ２ ) ｍ１ -CO-(CH ２ ) ｍ２ Compound 3B is preferred, which is a group represented by - and n is 2, and R is -CH ２ -CO-CH ２ Compound 3C is more preferable, which is a group represented by -, where X is a fluorine atom and n is 2.

[0028] CF ２ =CF-CFX-OSO ２ - (CH ２ ) ｍ１ -CO-(CH ２ ) ｍ２ -SO ２ O-CFX-CF=CF ２ (3B) CF ２ = CF - CF ２ - OSO ２ -CH ２ -CO-CH ２ -SO２ O-CF ２ -CF = CF ２ (3C)

[0029] In equation (3B), m1 and m2 are the same as m1 and m2 in equation (1B), respectively. In equation (3B), X is the same as X in equation (2).

[0030] <Compound 1A> Compound 1A used in step 0 is the compound represented by the following formula (1A): R-(SO ２ OH) ｎ (1A)

[0031] In equation (1A), R and n are the same as R and n in equation (1).

[0032] <Bases and Salts> In step 0, a base or a salt is used. The base and salt are not particularly limited as long as they are compounds that can form a salt with a sulfonic acid group. Specific examples of bases include organic bases such as pyridine, triethylamine, and imidazole, and inorganic bases such as potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, and silver oxide. Specific examples of salts include potassium chloride, sodium chloride, potassium bromide, potassium iodide, sodium fluoride, potassium fluoride, and sodium sulfate. In step 0, a solid that is poorly soluble in the solvent may be produced as a by-product, or an acidic gas may be produced, which may necessitate filtering out the by-product solid or abolishing the acidic gas. From the viewpoint of being able to form a sulfonate without producing by-product solids or acidic gases, it is preferable to use a base, an organic base, and more preferably pyridine among the bases and salts.

[0033] <Step 0> Step 0 is a step performed before Step 1 in which compound 1A is mixed with a base or salt to obtain compound 1. Compound 1 used in the method for producing sulfonic acid esters of the present invention may be produced by methods other than Step 0, but it is preferable to use the compound obtained by Step 0 because it is easier to obtain compound 1 of high purity.

[0034] The amount of base or salt used is preferably 2.0 molar equivalents or more, more preferably 5.0 molar equivalents or more, and preferably 10 molar equivalents or less, and more preferably 8.0 molar equivalents or less, relative to 1.0 molar equivalent of compound 1A.

[0035] The mixing of compound 1A with a base or salt is preferably carried out in the presence of a liquid medium. Specific examples of liquid media include organic solvents such as acetonitrile, dimethylformamide, and dimethylacetamide, and water. Of these, organic solvents are preferred, and acetonitrile is more preferred, from the viewpoint of the solubility of compound 1A. Two or more liquid media may be mixed and used. When using a liquid medium, the amount of liquid medium used is preferably 100 parts by mass or more, more preferably 500 parts by mass or more, and preferably 900 parts by mass or less, and more preferably 700 parts by mass or less, per 100 parts by mass of compound 1A.

[0036] The temperature at which compound 1A is mixed with a base or salt (reaction temperature) is preferably 0°C or higher, more preferably 20°C or higher, more preferably 80°C or lower, and more preferably 50°C or lower, from the viewpoint of ensuring a suitable reaction rate and suppressing side reactions to obtain the desired sulfonate with high purity.

[0037] In step 0, a purification process may be performed to purify the obtained compound 1. Performing a purification process has the advantage of obtaining compound 1 of high purity. Specific examples of purification processes include filtration and crystallization.

[0038] <Step 1> Step 1 is the step of reacting compound 1 and compound 2 to obtain compound 3.

[0039] The amount of compound 2 used is preferably 2.0 molar equivalents or more, more preferably 3.0 molar equivalents or more, and more preferably 10 molar equivalents or less, and more preferably 5.0 molar equivalents or less, relative to the amount of compound 1 used (1.0 molar equivalent).

[0040] The reaction between compound 1 and compound 2 is preferably carried out in the presence of a liquid medium. Specific examples of liquid media include organic solvents such as acetonitrile, dimethylformamide, dimethylacetamide, dimethoxyethane, dimethylethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, and sulfolane. Among these, acetonitrile is preferred from the viewpoint of sufficiently dissolving compound 1 and increasing the reaction yield. Two or more liquid media may be used in mixture form. When using a liquid medium, the amount of liquid medium used is preferably 100 parts by mass or more, more preferably 500 parts by mass or more, and preferably 900 parts by mass or less, and more preferably 700 parts by mass or less, per 100 parts by mass of compound 1.

[0041] The reaction temperature between compound 1 and compound 2 is preferably -30°C or higher, more preferably -10°C or higher, more preferably 50°C or lower, and more preferably 25°C or lower, from the viewpoint of ensuring a suitable reaction rate and suppressing side reactions to increase the yield of the target product.

[0042] [Method for Producing Fluorosulfonyl Group-Containing Compounds] <First Embodiment> The method for producing a fluorosulfonyl group-containing compound according to the first embodiment of the present invention includes the steps of obtaining compound 3 by the method for producing sulfonic acid esters of the present invention described above (i.e., step 1 described above; step 0 may be further included), and reacting compound 3 with an alkali metal fluoride to obtain compound 5 (hereinafter also referred to as "step 2"). This production method has the advantage that fluorosulfonyl group-containing compounds can be produced without using corrosive substances that cause corrosion of the production equipment (for example, hydrogen fluoride, thionyl chloride, etc.).

[0043] The following describes in detail a method for producing a fluorosulfonyl group-containing compound according to the first embodiment of the present invention. However, matters that have already been explained will be omitted.

[0044] (Alkali metal fluorides) Specific examples of alkali metal fluorides used in step 2 include sodium fluoride, potassium fluoride, and cesium fluoride. Among these, sodium fluoride is preferred from the viewpoint of suppressing excessive reaction with the resulting compound 5 and increasing the yield of the target product.

[0045] (Compound 5) Compound 5 obtained by step 2 is a compound represented by the following formula (5).

[0046] R-(SO ２ F) ｎ (5)

[0047] In equation (5), R and n are the same as R and n in equation (3), respectively.

[0048] - Compound 5B and Compound 5C In step 2, if the above-mentioned compound 3B, which is one embodiment of compound 3, is used, compound 5B, which is one embodiment of compound 5, is obtained, and if the above-mentioned compound 3C, which is one embodiment of compound 3, is used, compound 5C, which is one embodiment of compound 5, is obtained.

[0049] FSO ２ - (CH ２ ) ｍ１ -CO-(CH ２ ) ｍ２ -SO ２ F (5B) FSO ２ -CH ２ -CO-CH ２ -SO ２ F (5C)

[0050] In equation (5B), m1 and m2 are equivalent to m1 and m2 in equation (3B), respectively.

[0051] (Step 2) Step 2 is the step of reacting compound 3 with an alkali metal fluoride to obtain compound 5.

[0052] The amount of alkali metal fluoride used is preferably 0.05 molar equivalents or more, more preferably 0.1 molar equivalents or more, particularly preferably 1.0 equivalent or more, and preferably 10 molar equivalents or less, and more preferably 5.0 molar equivalents or less, relative to 1.0 molar equivalent of compound 3, from the viewpoint of carrying out the reaction at low cost, ensuring a suitable reaction rate, and suppressing side reactions to increase the yield of the target product.

[0053] The reaction between compound 3 and alkali metal fluoride is preferably carried out in the presence of a liquid medium. Specific examples of liquid mediums include organic solvents such as acetonitrile, dimethylformamide, dimethylacetamide, monoglyme, diglyme (diethylene glycol dimethyl ether), triglyme, tetraglyme, and sulfolane, as well as water. Among these, organic solvents are preferred, and acetonitrile is preferred, from the viewpoint of reaction yield. Two or more liquid media may be mixed and used. When using a liquid medium, the amount of liquid medium used is preferably 100 parts by mass or more, more preferably 500 parts by mass or more, and preferably 900 parts by mass or less, and more preferably 700 parts by mass or less, based on 100 parts by mass of the total amount of compound 3 and alkali metal fluoride used.

[0054] The reaction temperature between compound 3 and alkali metal fluoride is preferably -30°C or higher, more preferably 0°C or higher, preferably 60°C or lower, and more preferably 30°C or lower, from the viewpoint of ensuring a suitable reaction rate and suppressing side reactions to increase the yield of the target product.

[0055] <Second Embodiment> The method for producing a fluorosulfonyl group-containing compound according to the second embodiment of the present invention includes the steps of: obtaining compound 3B by the method for producing a sulfonic acid ester of the present invention described above (i.e., a manner in which compound 1B and compound 2 are reacted in step 1 described above; step 0 may be further included); reacting compound 3B with an alkali metal fluoride to obtain compound 5B (i.e., a manner in which compound 3B and an alkali metal fluoride are reacted in step 2 described above); fluorinating compound 5B to obtain compound 6B (hereinafter also referred to as "step 3"); and reacting compound 6B with compound 2B to obtain compound 7B (hereinafter also referred to as "step 4").

[0056] The method for producing a fluorosulfonyl group-containing compound according to the second embodiment of the present invention will be described in detail below. However, matters that have already been explained will be omitted.

[0057] (Compound 6B) Compound 6B obtained by step 3 is a compound represented by the following formula (6B).

[0058] FSO ２ - (CF ２ ) ｍ１ -CO-(CF ２ ) ｍ２ -SO ２ F (6B)

[0059] In equation (6B), m1 and m2 are equivalent to m1 and m2 in equation (5B), respectively.

[0060] - Compound 6C: If compound 5C, which is an embodiment of compound 5B, is used in step 3, compound 6C, which is an embodiment of compound 6B, is obtained. FSO ２ -CF ２ -CO-CF ２ -SO ２ F (6C)

[0061] (Compound 7B) Compound 7B obtained by step 4 is a compound represented by the following formula (7B).

[0062] CF ２ = CF - CF ２-O-CF[(CF ２ ) ｍ１ -SO ２ F] [(CF ２ ) ｍ２ -SO ２ F] (7B)

[0063] In equation (7B), m1 and m2 are equivalent to m1 and m2 in equation (6B), respectively.

[0064] - Compound 7C: If compound 6C, which is one embodiment of compound 6B, is used in step 4, compound 7C, which is one embodiment of compound 7B, is obtained.

[0065] CF ２ = CF - CF ２ -O-CF(CF ２ -SO ２ F) ２ (7C)

[0066] (Step 3) Step 3 is a step to obtain compound 6B by fluorinating compound 5B. A method for fluorinating compound 5B is to contact compound 5B with fluorine gas or a fluorine compound. Examples of fluorine compounds include hydrogen fluoride, halogen fluorides (chlorine trifluoride, iodine pentafluoride, etc.), gaseous fluorides (boron trifluoride, nitrogen trifluoride, phosphorus pentafluoride, silicon tetrafluoride, sulfur hexafluoride, etc.), metallic fluorides (lithium fluoride, nickel(II) fluoride, etc.), hypofluorite compounds (trifluoromethyl hypofluorite, trifluoroacetyl hypofluorite, etc.), and electrophilic fluorination reagents (SelectFluor®, N-fluorobenzenesulfonimide, etc.). As a method of fluorination, contact between compound 5B and fluorine gas is preferred because it is easy to handle and reduces the amount of impurities contained in compound 6B. Fluorine gas may be used after being diluted with an inert gas such as nitrogen gas.

[0067] Fluorination of compound 5B is preferably carried out in the presence of a liquid medium. The liquid medium can be appropriately selected from solvents that have high solubility for compound 5B and are not easily fluorinated themselves. Specific examples of liquid media include acetonitrile, chloroform, dichloromethane, trichlorofluoromethane, perfluorotrialkylamines (perfluorotributylamine, etc.), perfluorocarbons (perfluorohexane, perfluorooctane, etc.), hydrofluorocarbons (1H,4H-perfluorobutane, 1H-perfluorohexane, etc.), hydrochlorofluorocarbons (3,3-dichloro-1,1,1,2,2-pentafluoropropane, 1,3-dichloro-1,1,2,2,3-pentafluoropropane, etc.), and hydrofluoroethers (CF ３ CH ２ OCF ２ CF ２ Examples include H, etc. Two or more liquid media may be mixed and used. When using a liquid media, the amount of liquid media used is preferably 100 parts by mass or more, more preferably 500 parts by mass or more, and preferably 900 parts by mass or less, and more preferably 700 parts by mass or less, per 100 parts by mass of compound 5B used.

[0068] The reaction temperature for fluorinating compound 5B is preferably -10°C or higher, more preferably 0°C or higher, more preferably 50°C or lower, and more preferably 20°C or lower, from the viewpoint of ensuring a suitable reaction rate, suppressing side reactions, and increasing the yield of the target product, as well as from the viewpoint of reaction stability.

[0069] In the fluorination of compound 5B, if hydrogen fluoride (HF) is present in the reaction system, hydrogen fluoride may be added to compound 5B, resulting in a state of equilibrium with compound 5B' (alcohol form), or the compound 5B' itself. In this specification, even when simply referred to as compound 5B, it may represent either compound 5B or compound 5B', or both.

[0070] FSO ２ - (CH ２ ) ｍ１ -CF(OH)-(CH ２ ) ｍ２ -SO２ F (5B')

[0071] In equation (5B'), m1 and m2 are equivalent to m1 and m2 in equation (5B), respectively.

[0072] (Step 4) Step 4 is the step of reacting compound 6B and compound 2B to obtain compound 7B.

[0073] The reaction between compound 6B and compound 2B is preferably carried out in the presence of a liquid medium. The liquid medium preferably contains an aprotic polar solvent, and more preferably contains only an aprotic polar solvent. Examples of aprotic polar solvents include monoglyme, diglyme (diethylene glycol dimethyl ether), triglyme, tetraglyme, acetonitrile, propionitrile, adiponitrile, benzonitrile, dioxane, tetrahydrofuran, N,N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, and nitroethane. Two or more liquid media may be used in mixture form. When using a liquid medium, the amount of liquid medium used is preferably 100 to 900 parts by mass, and more preferably 500 to 700 parts by mass, per 100 parts by mass of the total amount of compound 6B and compound 2B used.

[0074] The reaction between compound 6B and compound 2B is preferably carried out in the presence of a fluoride salt. Specific examples of fluoride salts include potassium fluoride, cesium fluoride, silver fluoride, quaternary ammonium fluoride, and sodium fluoride. When using a fluoride salt, the amount of fluoride salt used is preferably 0.8 to 10 molar equivalents, and more preferably 1.0 to 8.0 molar equivalents, relative to 1.0 molar equivalent of compound 6B.

[0075] The reaction temperature between compound 6B and compound 2B is preferably -30°C or higher, more preferably 0°C or higher, preferably 30°C or lower, and more preferably 60°C or lower, from the viewpoint of ensuring a suitable reaction rate and suppressing side reactions to increase the yield of the target product.

[0076] [Method for producing polymers] The method for producing polymers of the present invention comprises the steps of: obtaining compound 7B by the method for producing a fluorosulfonyl group-containing compound according to the second embodiment of the present invention described above (i.e., steps 1 to 4 described above; step 0 described above may be further included); and polymerizing the monomer containing compound 7B to obtain a polymer having units based on compound 7B (hereinafter also referred to as "step 5"). Furthermore, the method for producing polymers of the present invention preferably further comprises the step of subjecting the polymer having units based on compound 7B to a hydrolysis treatment to obtain a polymer having units 8B (hereinafter also referred to as "step 6").

[0077] In the following sections, each compound will be described, followed by a description of each step. However, explanations of matters already covered will be omitted.

[0078] <Monomer> The monomer used in step 5 contains compound 7B. Compound 7B is preferably compound 7C as described above.

[0079] The monomer used in step 5 preferably further contains other monomers. Specific examples of other monomers include tetrafluoroethylene (hereinafter also referred to as "TFE"), chlorotrifluoroethylene, trifluoroethylene, vinylidene fluoride, vinyl fluoride, ethylene, propylene, perfluoro(3-butenyl vinyl ether), perfluoro(allyl vinyl ether), perfluoroα-olefin (hexafluoropropylene, etc.), (perfluoroalkyl)ethylene ((perfluorobutyl)ethylene, etc.), (perfluoroalkyl)propene (3-perfluorooctyl-1-propene, etc.), perfluoro(alkyl vinyl ether), and perfluoromonomers having a five-membered ring as described in International Publication No. 2011 / 013578. Among these, TFE is preferred. Two or more of the other monomers may be used.

[0080] <Polymers having units based on Compound 7B (Polymer F)> Polymers having units based on Compound 7B are polymers containing fluorosulfonyl groups, and are also referred to as "Polymer F" below.

[0081] The unit based on compound 7B is specifically the unit represented by formula (7B-1) (i.e., unit 7B-1).

[0082]

[0083] In equation (7B-1), m1 and m2 are equivalent to m1 and m2 in equation (7B), respectively.

[0084] The unit 7B-1 is preferably a unit based on compound 7C, specifically a unit represented by formula (7C-1) (i.e., unit 7C-1).

[0085]

[0086] Polymer F preferably has units based on the other monomers mentioned above, in addition to unit 7B-1.

[0087] The content of unit 7B-1 is preferably 2.7 mol% or more, and more preferably 8.3 mol% or more, relative to the total units in polymer F. Furthermore, the content of unit 7B-1 is preferably 36.0 mol% or less, and more preferably 33.6 mol% or less, relative to the total units in polymer F. If it is above the lower limit, the ionic conductivity of polymer H (described later) will be high, so sufficient battery output can be obtained when used in the solid polymer electrolyte membrane or catalyst layer of a solid polymer fuel cell. Also, when used in ion exchange membranes for alkali chloride electrolysis or water electrolysis, the overvoltage such as membrane resistance will be reduced, so the power consumption per unit can be suppressed. If it is below the upper limit, swelling when polymer H absorbs water will be suppressed, and the mechanical strength will be increased when used as a solid polymer electrolyte membrane. Alternatively, when used in the catalyst layer, flooding of the solid polymer fuel cell can be suppressed. Furthermore, if polymer F has TFE units, the content of TFE units is preferably 20 mol% or more, and more preferably 64 mol% or more, relative to the total units in polymer F. Furthermore, the TFE unit content is preferably 97.3 mol% or less, and more preferably 91.7 mol% or less, relative to the total units in polymer F. If it is above the lower limit, the elongation of polymer H (described later) increases, making it less prone to cracks and fissures when used as a solid polymer electrolyte membrane or catalyst layer in a solid polymer fuel cell. Also, when used as an ion exchange membrane for alkali chloride electrolysis or water electrolysis, a membrane with excellent mechanical strength can be obtained. If it is below the upper limit, when used as a solid polymer electrolyte membrane or catalyst layer in a solid polymer fuel cell, a membrane or catalyst layer with excellent proton conductivity can be obtained, resulting in sufficient battery output. Also, when used as an ion exchange membrane for alkali chloride electrolysis or water electrolysis, the overvoltage such as membrane resistance decreases, thus suppressing power consumption per unit.

[0088] The proportion of units based on unit 7B-1 and other monomers among all the units constituting polymer F should be appropriately determined according to the required properties and physical characteristics (ion exchange capacity, ionic conductivity, mechanical strength, elastic modulus, softening temperature, free volume, gas permeability, water vapor permeability, water diffusivity, transport rate, degree of swelling, size of phase separation structure, particle size of dispersed particles in the liquid composition, viscosity of the liquid composition, storage modulus of the liquid composition, etc.) depending on the application of the sulfonic acid group-containing polymer.

[0089] The volumetric flow rate (TQ value) of polymer F is preferably 200°C or higher, and more preferably 205°C or higher, since the sulfonic acid group-containing polymer has sufficient molecular weight and excellent mechanical strength. The TQ value of polymer F is preferably 330°C or lower, and more preferably 260°C or lower, since the solubility or dispersibility of the sulfonic acid group-containing polymer is improved, and the liquid composition described later is easier to prepare. The TQ value is an indicator of the molecular weight of polymer F and is determined by the method described in the Examples section below.

[0090] The glass transition temperature (Tg) of polymer F is preferably 5°C or higher, and more preferably 15°C or higher, from the viewpoint of suppressing the tackiness of polymer F and improving handling and storage stability. The Tg of polymer F is preferably 70°C or lower, and more preferably 55°C or lower, from the viewpoint of suppressing the brittleness of polymer F pellets and films. The Tg can be determined by the method described in the Examples section below.

[0091] <Polymers containing unit 8B (polymer H)> Polymers containing unit 8B are polymers containing sulfonic acid groups, and are also referred to as "polymer H" below.

[0092] The unit 8B is a unit represented by formula (8B).

[0093]

[0094] Unit 8B is preferably the unit represented by formula (8C) (i.e., unit 8C).

[0095] Polymer H preferably has units based on the other monomers mentioned above, in addition to unit 8B.

[0096] The ion exchange capacity of polymer H is preferably 0.5 milliequivalents / g dry resin or higher, and more preferably 1.3 milliequivalents / g dry resin or higher. If the ion exchange capacity is 0.5 milliequivalents / g dry resin or higher, the ionic conductivity of polymer H is high, so when used in the solid polymer electrolyte membrane or catalyst layer of a solid polymer fuel cell, sufficient battery output can be obtained. Also, when used in ion exchange membranes for alkali chloride electrolysis or water electrolysis, the overvoltage such as membrane resistance is reduced, so the power consumption per unit can be suppressed. The ion exchange capacity of polymer H is preferably 2.5 milliequivalents / g dry resin or lower, and more preferably 2.3 milliequivalents / g dry resin or lower. If the ion exchange capacity is 2.5 milliequivalents / g dry resin or lower, swelling when polymer H absorbs water is suppressed, and the mechanical strength is increased when used as a solid polymer electrolyte membrane. Alternatively, when used in the catalyst layer, flooding of the solid polymer fuel cell can be suppressed. The ion exchange capacity can be determined by the method described in the Examples section below.

[0097] The softening temperature of polymer H is preferably 100°C or higher, and more preferably 140°C or higher, because it increases the mechanical strength at high temperatures when used as a solid polymer electrolyte membrane. The softening temperature of polymer H is preferably 180°C or lower, and more preferably 160°C or lower, because it allows for lower temperatures for annealing the solid polymer electrolyte membrane or for the hot pressing required for transferring the catalyst layer or forming the membrane electrode assembly. The softening temperature is determined by the method described in the Examples section below.

[0098] The water content (by mass) of polymer H is preferably 30% or more, and more preferably 40% or more, since this increases the ionic conductivity of polymer H and results in a membrane electrode assembly with even better power generation performance. The water content (by mass) of polymer H is preferably 300% or less, and more preferably 200% or less, since polymer H does not swell excessively with water, thus maintaining the mechanical strength of the solid polymer electrolyte membrane.

[0099] Specific examples of applications for polymer H include polymers contained in liquid compositions for forming polymer-containing membranes, polymers contained in catalyst layers and solid polymer electrolyte membranes in membrane electrode assemblies for polymer electrolyte fuel cells, polymers contained in catalyst layers and solid polymer electrolyte membranes in membrane electrode assemblies for polymer electrolyte water electrolysis, polymers contained in cation exchange membranes used in alkali chloride electrolysis and electrodialysis, polymers contained in diaphragms for redox flow secondary batteries, polymers contained in ion exchange membranes used in alkaline water electrolysis and PEM-type water electrolysis, polymers contained in ion exchange membranes for electrochemical hydrogen pumps, polymers contained in cation exchange resins used in ion-conductive polymer actuators and gas sensors, polymers used in solid acid catalysts, polymers used in membrane-type humidity control devices such as dehumidifiers and humidifiers, and polymers used in gas separation membranes.

[0100] <Step 5> Step 5 is a step of polymerizing a monomer containing compound 7B to obtain a polymer having units based on compound 7B (i.e., unit 7B-1).

[0101] Polymerization methods include bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. Polymerization may also be carried out in liquid or supercritical carbon dioxide. Polymerization is carried out under conditions that generate radicals. Methods for generating radicals include irradiation with radiation such as ultraviolet rays, gamma rays, and electron beams, and adding radical initiators. The polymerization temperature is preferably 10 to 150°C.

[0102] Specific examples of radical initiators include bis(fluoroacyl) peroxides, bis(chlorofluoroacyl) peroxides, dialkylperoxydicarbonates, diacyl peroxides, peroxyesters, azo compounds, and persulfates. Perfluoro compounds such as bis(fluoroacyl) peroxides are preferred because they yield polymer F with fewer unstable end groups.

[0103] For solvents used in solution polymerization, solvents having a boiling point of 20 to 350°C are preferred, and solvents having a boiling point of 40 to 150°C are more preferred. Examples of solvents include perfluorotrialkylamines (perfluorotributylamine, etc.), perfluorocarbons (perfluorohexane, perfluorooctane, etc.), hydrofluorocarbons (1H,4H-perfluorobutane, 1H-perfluorohexane, etc.), hydrochlorofluorocarbons (3,3-dichloro-1,1,1,2,2-pentafluoropropane, 1,3-dichloro-1,1,2,2,3-pentafluoropropane, etc.), and hydrofluoroethers (CF ３ CH ２ OCF ２ CF ２ Examples include H, etc.

[0104] In solution polymerization, monomers, radical initiators, etc., are added to a solvent, and radicals are generated in the solvent to polymerize the monomers. The monomers and radical initiators may be added all at once, sequentially, or continuously.

[0105] In suspension polymerization, it is preferable to use water as the dispersion medium, add monomers, nonionic radical initiators, etc., to the dispersion medium, and generate radicals in the dispersion medium to polymerize the monomers. Examples of nonionic radical initiators include bis(fluoroacyl) peroxides, bis(chlorofluoroacyl) peroxides, dialkylperoxydicarbonates, diacyl peroxides, peroxyesters, dialkyl peroxides, bis(fluoroalkyl) peroxides, and azo compounds. For example, organic solvents may be added to the dispersion medium as auxiliary agents, surfactants as dispersion stabilizers to prevent aggregation of suspended particles, and hydrocarbon compounds (hexane, methanol, etc.) as molecular weight modifiers.

[0106] In emulsion polymerization, monomers are emulsified in water in the presence of an emulsifier and a polymerization initiator, and the monomers are polymerized. Compounds commonly used in emulsion polymerization of fluorine-containing monomers can be used as the emulsifier and polymerization initiator. A specific example of an emulsifier is CF ３ CF ２ CF２ CF ２ OCF ２ COONH ４ CF ３ CF ２ OCF ２ CF ２ OCF ２ COONH ４ Examples of ammonium perfluorocarboxylate salts include those listed above. Examples of polymerization initiators include radical initiators such as peroxides, azo compounds, and persulfates. In addition, initiators may be activated by oxidation-reduction reactions of metal ions, etc. In addition to these, buffers, chain transfer agents, etc., which are commonly used when emulsion polymerization of fluorine-containing monomers, may be used as appropriate. Furthermore, in order to increase the reaction rate of the monomers, the mixture of aqueous solvent and monomers may be forcibly emulsified using a homogenizer, pressurized emulsifier, etc., before the start of polymerization.

[0107] <Step 6> Step 6 is a step in which a polymer (polymer F) having units based on compound 7B (i.e., unit 7B-1) is subjected to hydrolysis to obtain a polymer (polymer H) having units 8B. In step 6, an acidification treatment may be performed after the hydrolysis treatment. By performing step 6, the fluorosulfonyl groups in unit 7B-1 are converted to sulfonic acid groups. Specifically, the fluorosulfonyl groups of polymer F become salt-type sulfonic acid groups through hydrolysis, and the salt-type sulfonic acid groups become acid-type sulfonic acid groups through the acidification treatment. Note that if salt-type sulfonic acid groups are desired, the acidification treatment does not need to be performed.

[0108] A specific example of hydrolysis treatment is a process in which polymer F is brought into contact with a basic compound in a solvent. Examples of basic compounds include sodium hydroxide, potassium hydroxide, and triethylamine. Examples of solvents include water and mixed solvents of water and a polar solvent. Examples of polar solvents include alcohols (methanol, ethanol, etc.) and dimethyl sulfoxide.

[0109] A specific example of acidification treatment is to bring a polymer H having a salt-type sulfonic acid group into contact with an aqueous solution of hydrochloric acid, sulfuric acid, nitric acid, etc.

[0110] The temperature for hydrolysis and acidification is preferably 0 to 120°C. After hydrolysis or acidification, it is preferable to wash polymer H with water.

[0111] [Method for Producing a Liquid Composition] The method for producing a liquid composition of the present invention includes the steps of: obtaining a polymer having unit 8B (polymer H) by the polymer production method of the present invention described above (i.e., steps 1 to 6 described above; step 0 described above may be further included); and mixing polymer H with a liquid medium to obtain a liquid composition (hereinafter also referred to as "step 7"). The method for producing a liquid composition of the present invention will be described in detail below. However, matters that have already been described will be omitted from further explanation.

[0112] <Liquid Medium> The liquid medium may be water alone, an organic solvent alone, or a mixture of water and an organic solvent, but a mixture of water and an organic solvent is preferred. Water improves the dispersibility or solubility of polymer H in the liquid medium. The organic solvent facilitates the formation of a crack-resistant catalyst layer or solid polymer electrolyte membrane.

[0113] As the organic solvent, one or more alcohols having 1 to 4 carbon atoms are preferred because they readily form a catalyst layer that is less prone to cracking and a solid polymer electrolyte membrane. Examples of alcohols having 1 to 4 carbon atoms include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2,2,2-trifluoroethanol, 2,2,3,3,3-pentafluoro-1-propanol, 2,2,3,3-tetrafluoro-1-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, and 3,3,3-trifluoro-1-propanol.

[0114] <Liquid Composition> The liquid composition obtained through step 7 may be a mixture of polymer H dispersed in a liquid medium, or a mixture of polymer H dissolved in a liquid medium.

[0115] The liquid medium content is preferably 50% by mass or more, more preferably 70% by mass or more, and preferably 99% by mass or less, and more preferably 97% by mass or less, based on the total mass of the liquid composition. If the liquid medium contains water, the water content is preferably 10% by mass or more, more preferably 20% by mass or more, and preferably 99% by mass or less, based on the total mass of the liquid medium. If the liquid medium contains an organic solvent, the organic solvent content is preferably 1% by mass or more, more preferably 90% by mass or less, and more preferably 80% by mass or less, based on the total mass of the liquid medium.

[0116] The polymer H content is preferably 1% by mass or more, more preferably 3% by mass or more, and more preferably 50% by mass or less, and more preferably 30% by mass or less, based on the total mass of the liquid composition.

[0117] <Step 7> Step 7 is a step of mixing polymer H with a liquid medium to obtain a liquid composition. As for the mixing method, for example, a method of applying shear, such as stirring, to the polymer H in the liquid medium under atmospheric pressure or in a sealed state such as an autoclave. The temperature during stirring is preferably 0°C or higher, more preferably 20°C or higher, preferably 250°C or lower, and more preferably 150°C or lower. If necessary, shear such as ultrasonic waves may be applied.

[0118] When applying shearing forces such as stirring to a mixture of polymer H and a liquid medium, the mixture may be prepared by adding all of the liquid medium to the polymer H at once and then applying the shearing forces, or the liquid medium may be mixed with the polymer H in multiple stages, with stirring or other shearing forces applied in between. For example, the mixture may be prepared by adding a portion of the liquid medium to the polymer H and then applying the shearing forces, followed by adding the remaining liquid medium and applying the shearing forces again. Alternatively, only an organic solvent may be added to the liquid medium and then applied the shearing forces, followed by adding only water and applying the shearing forces again.

[0119] [Method for Manufacturing a Film] The method for manufacturing a film according to the present invention includes the steps of obtaining a liquid composition by the method for manufacturing a liquid composition according to the present invention described above (i.e., steps 1 to 7 described above; step 0 described above may be further included), and obtaining a film using the liquid composition (hereinafter also referred to as "step 8"). The method for manufacturing a film according to the present invention will be described in detail below. However, matters that have already been explained will be omitted from the explanation.

[0120] <Membrane> The membrane obtained through step 8 contains polymer H and may further contain reinforcing material. The membrane obtained through step 8 may also further contain components other than polymer H and reinforcing material. Examples of reinforcing material include porous materials, fibers, woven fabrics, and nonwoven fabrics. Examples of materials for the reinforcing material include various polymers, which are appropriately selected according to the application of the membrane. When the membrane is a solid polymer electrolyte membrane in a membrane electrode assembly for a solid polymer fuel cell, examples of materials for the reinforcing material include polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymer, polyethylene, polypropylene, polyphenylene sulfide, and polyether ether ketone.

[0121] Applications of the membranes include catalyst layers and solid polymer electrolyte membranes in membrane electrode assemblies for polymer electrolyte fuel cells, catalyst layers and solid polymer electrolyte membranes in membrane electrode assemblies for polymer electrolyte water electrolysis, cation exchange membranes used in alkali chloride electrolysis and electrodialysis, ion exchange membranes used in water electrolysis, diaphragms for redox flow secondary batteries, and ion exchange membranes for electrochemical hydrogen pumps.

[0122] <Step 8> Step 8 is a step in which a film is obtained using a liquid composition. Specific examples of film manufacturing methods include a method of applying the liquid composition to a substrate and drying it (casting method). If a reinforcing material is further included, examples include a method of impregnating the reinforcing material with the liquid composition of the present invention and drying it, or a method of bonding the film obtained by the above method with the reinforcing material. When the film is a solid polymer electrolyte membrane in a membrane electrode assembly for a solid polymer fuel cell, the solid polymer electrolyte membrane can be formed, for example, by applying the liquid composition onto a substrate film or catalyst layer and drying it. When the film is a catalyst layer in a membrane electrode assembly for a solid polymer fuel cell, the catalyst layer can be formed by applying the catalyst layer forming composition to a solid polymer electrolyte membrane, gas diffusion layer, etc., and drying it, or by applying the catalyst layer forming composition onto a substrate film, drying it to form a catalyst layer, and then transferring the catalyst layer onto the solid polymer electrolyte membrane. The catalyst layer forming composition can be prepared, for example, by mixing a liquid composition and a catalyst dispersion.

[0123] [Method for Manufacturing a Membrane Electrode Assembly] The present invention provides a method for manufacturing a membrane electrode assembly comprising: an anode having a catalyst layer; a cathode having a catalyst layer; and a solid polymer electrolyte membrane disposed between the anode and the cathode, comprising: a step of obtaining a liquid composition by the method for manufacturing a liquid composition of the present invention described above (i.e., steps 1 to 7 described above; step 0 described above may be further included); a step of mixing the liquid composition with a catalyst to obtain a catalyst layer forming composition (hereinafter also referred to as "step 9"); and a step of obtaining a catalyst layer for at least one of the anode and the cathode using the catalyst layer forming composition (hereinafter also referred to as "step 10"). The method for manufacturing a membrane electrode assembly of the present invention will be described in detail below. However, matters that have already been described will be omitted from further explanation.

[0124] <Composition for forming a catalyst layer> The composition for forming a catalyst layer obtained by step 9 comprises the liquid composition described above and a catalyst.

[0125] Specific examples of catalysts include supported catalysts in which a catalyst containing platinum, a platinum alloy, or platinum having a core-shell structure is supported on a carbon support, iridium oxide catalysts, composite oxide catalysts containing iridium and other metal elements, alloys containing iridium oxide, and catalysts containing iridium oxide having a core-shell structure. Examples of carbon supports include carbon black powder, acetylene black powder, and mesoporous carbon powder. Alternatively, inorganic oxide supports such as ceramics may be used instead of the carbon supports mentioned above.

[0126] The catalyst may be mixed with the liquid composition in the form of a catalyst dispersion containing the catalyst and a dispersion medium for dispersing the catalyst. In this case, a specific example of the dispersion medium in the catalyst dispersion is the liquid medium in the liquid composition described above.

[0127] The catalyst content is preferably 5 parts by mass or more, more preferably 7 parts by mass or more, and preferably 10 parts by mass or less, and more preferably 9 parts by mass or less, based on the total mass of the catalyst layer forming composition. When the catalyst layer forming composition contains a supported catalyst, the ratio of the mass of polymer H to the mass of the support in the supported catalyst (mass of polymer H / mass of support) is preferably 0.2 or more, more preferably 0.4 or more, and preferably 2.2 or less, and more preferably 1.5 or less.

[0128] The polymer H content is preferably 1% by mass or more, more preferably 2% by mass or more, and more preferably 5% by mass or less, and more preferably 4% by mass or less, based on the total mass of the catalyst layer forming composition.

[0129] The liquid medium content is preferably 80% by mass or more, more preferably 85% by mass or more, and more preferably 98% by mass or less, and more preferably 95% by mass or less, based on the total mass of the catalyst layer forming composition.

[0130] <Membrane electrode assembly> The membrane electrode assembly obtained through step 9 comprises an anode having a catalyst layer, a cathode having a catalyst layer, and a solid polymer electrolyte membrane disposed between the anode and the cathode.

[0131] (Anode and Cathode) The anode and cathode each have a catalyst layer and may further have a gas diffusion layer. The gas diffusion layer has the function of uniformly diffusing gas into the catalyst layer and the function of a current collector. Examples of gas diffusion layers include carbon paper, carbon cloth, and carbon felt. It is preferable that the gas diffusion layer is treated to be water-repellent with polytetrafluoroethylene or the like.

[0132] (Solid Polymer Electrolyte Membrane) A solid polymer electrolyte membrane can be formed, for example, by a method (casting method) in which an electrolyte membrane-forming composition is applied to a substrate film or catalyst layer and dried. The electrolyte membrane-forming composition is a dispersion in which a fluorine-containing polymer is dispersed in a solvent containing at least one of an organic solvent and water. Known polymers can be used as the fluorine-containing polymer. The solid polymer electrolyte membrane may be reinforced with the reinforcing material described above.

[0133] (Applications) The membrane electrode assembly can be used, for example, in the manufacture of polymer electrolyte fuel cells and polymer electrolyte water electrolyzers.

[0134] <Step 9> Step 9 is a step of mixing the liquid composition and the catalyst to obtain a composition for forming a catalyst layer. The mixing method is not particularly limited, and known methods can be used.

[0135] <Step 10> Step 10 is a step of obtaining at least one catalyst layer of the anode and cathode using the catalyst layer forming composition described above. A method for obtaining the catalyst layer is the method described in Step 8 above.

[0136] The membrane electrode assembly is manufactured, for example, by the following methods: (i) forming a catalyst layer on a solid polymer electrolyte membrane to form a membrane catalyst layer assembly, and sandwiching the membrane catalyst layer assembly between gas diffusion layers; (ii) forming a catalyst layer on a gas diffusion layer to form electrodes (anode and cathode), and sandwiching a solid polymer electrolyte membrane between the electrodes. In these methods, the method for forming the catalyst layer is as described in step 10.

[0137] [Compound] The compound of the present invention is the compound represented by formula (3) above (i.e., compound 3). Compound 3 is preferably compound 3B above, and more preferably compound 3C above. The details of compound 3, compound 3B, and compound 3C are as described above. Compound 3, compound 3B, and compound 3C can be produced by the method for producing sulfonic acid esters of the present invention described above.

[0138] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Examples 1-1 and 2 to 8 are examples, and examples 1-2 to 1-4 are comparative examples.

[0139] ( １ H-NMR) １ ¹H-NMR measurements were performed under the following conditions: frequency: 300.4 MHz, chemical shift reference: tetramethylsilane. Unless otherwise specified, CD was used as the solvent. ３ CN was used. Quantitative analysis of the product was performed. １ The analysis was performed based on the results of 1H-NMR and the amount of internal standard sample (1,3-bis(trifluoromethyl)benzene) added.

[0140] ( １９ F-NMR) １９ F-NMR was performed at a frequency of 282.7 MHz, using CD as the solvent. ３ CN, chemical shift standard: CFCl ３ The measurement was performed under the following conditions. The quantification of the product was performed as follows: １９ The analysis was performed based on the results of F-NMR and the amount of internal standard sample (1,3-bis(trifluoromethyl)benzene) added.

[0141] ( １３ C-NMR) １３ ¹³C-NMR measurements were performed under the following conditions: frequency: 75.5 MHz, chemical shift reference: tetramethylsilane. Unless otherwise specified, CD was used as the solvent. ３ CN was used.

[0142] (Yield) Yield refers to the yield of the reaction step multiplied by the yield of the purification step. Reaction yield refers to the yield of the reaction step before the target product is purified, excluding the losses in the purification step.

[0143] (Ion exchange capacity) A polymer H film was vacuum-dried at 120°C for 12 hours. After measuring the weight of the dried polymer film, the polymer film was immersed in a 0.85 mol / g sodium hydroxide solution (solvent: water / methanol = 10% by mass / 90% by mass) to neutralize the ion exchange groups. The neutralized sodium hydroxide solution was back-titrated with 0.1 mol / L hydrochloric acid to determine the ion exchange capacity of polymer H (milliequivalents / g dry resin).

[0144] (Percentage of units based on fluorosulfonyl group-containing compounds) Fluorosulfonyl group-containing compounds in polymer F (SO ２ The proportion of units based on F-group-containing compounds is for polymer F. １９ This was determined from the F-NMR measurement results.

[0145] (TQ value) Using a flow tester equipped with a nozzle with an inner diameter of 1 mm and a length of 1 mm (Shimadzu Corporation's capillary rheometer flow tester, CFT-500D), the cross-sectional area was 1 cm². ２ Polymer F, filled into a cylinder, was extruded from a nozzle at 260°C under a 30 kg load and a pressure of 2.94 MPa. At that time, the volumetric flow rate (mm) of the extruded polymer was measured when the extrusion speed of the polymer stabilized. ３ The Q value was defined as (Q / second). Also, a Q value of 100 mm ３ The temperature at which the reaction rate is obtained was defined as the TQ value. A higher TQ value indicates a larger molecular weight of the polymer.

[0146] (Dynamic Viscoelasticity Measurement) Dynamic viscoelasticity measurements were performed on a film of polymer F or a film of polymer H using a dynamic viscoelasticity measuring device (DVA-225, manufactured by IT Measurement Control Co., Ltd.) under the following conditions: sample width: 5.0 mm, gripping distance: 15 mm, measurement frequency: 1 Hz, heating rate: 2 °C / min, and tensile mode. The tanδ (loss tangent) was calculated from the ratio of the loss modulus E'' to the storage modulus E' (E'' / E'), and the peak temperature between -100 and 200 °C read from the tanδ-temperature curve was taken as the Tg of polymer F or the softening temperature of polymer H. In addition, a storage modulus E'-temperature curve was created, and the storage modulus at 120 °C was read as the 120 °C modulus of polymer H.

[0147] (Conductivity) A substrate with four-terminal electrodes arranged at 5 mm intervals was placed in close contact with a polymer H film with a thickness of 25 μm and a width of 5 mm. The resistance of the polymer H film was measured using a known four-terminal method under constant temperature and humidity conditions of 80°C and 50% relative humidity, with AC: 10 kHz and voltage: 1 V, and the conductivity was calculated. The reference dimensions and film thickness of the film used in the calculation were measured under conditions of 23°C and 50% RH relative humidity.

[0148] (Moisture Content) A polymer H film was immersed in 80°C hot water for 16 hours, and then cooled until the water temperature dropped to below 25°C. The polymer H film was removed, the water adhering to the surface of the film was wiped off with filter paper, and the mass W1 of polymer H was measured. After drying the polymer H film in a glove box under a nitrogen atmosphere for more than 48 hours, the mass W2 of the polymer H film was measured in the glove box. The moisture content (mass basis) was calculated using the following formula 1. Moisture content = (W1 - W2) / W2 × 100 (Formula 1)

[0149] (Abbreviation) PSVE:CF ２ = CFOCF ２ CF (CF ３ ) OCF ２ CF ２ SO ２ F, TFE:CF ２ =CF ２ , PFtBPO: (CF ３ ) ３ COOC (CF ３ ) ３ , HFC-52-13p:CF ３ (CF ２ ) ５ H, HFE-347pc-f:CF ３ CH ２ OCF ２ CF ２ H.

[0150] [Example 1-1] <Preparation of Compound 1C-1> 70.6 g of Compound 1A-1 was placed in a 1 L four-necked flask equipped with a stirrer, condenser, thermometer, and dropping funnel, under a nitrogen gas seal. 500 mL of acetonitrile was added, and the flask was cooled with ice. 52.6 g of pyridine was added dropwise while maintaining the internal temperature at 0-5°C. Heat generation and white fumes were observed during the addition. After the addition was complete, the internal temperature was maintained at room temperature and the reaction was allowed to proceed for 16 hours. The white solid that precipitated as the reaction progressed was collected by filtration and dried under a nitrogen gas stream for 12 hours. The dried solid was then... １ Analysis by 1H-NMR confirmed that 97.3 g of compound 1C-1 with a purity of 95% by mass was obtained. The yield of compound 1C-1 relative to compound 1A-1 was 76%.

[0151]

[0152] NMR spectrum of compound 1C-1: １ 1H-NMR (deuterated solvent: D ２ O): 4.13 ppm (-CH ２ -, 4H, s), 7.96 (-CH, 4H, t, J = 7Hz), 8.50ppm (-CH, 2H, m), 8.66ppm (-CH, 4H, d, J = 5Hz).

[0153] <Preparation of Compound 3C> 10.1 g of Compound 1C-1 was placed in a 100 mL four-necked flask equipped with a stirrer, condenser, thermometer, and dropping funnel, under a nitrogen gas seal. 70 mL of acetonitrile was added, and the flask was cooled with ice. While maintaining the internal temperature at 0-5°C, CF ２ = CF - CF ２ - OSO ２ 14.3 g of F was added dropwise. After the addition was complete, the internal temperature was maintained at 0-5°C and the reaction was allowed to proceed for 15 hours. After the reaction was complete, the precipitated white solid was removed by filtration, and the filtrate was concentrated by evaporation. The concentrated slightly yellowish oil was then... １ H-NMR and １９ Analysis by F-NMR confirmed that 8.63 g of compound 3C with a purity of 80% by mass was obtained. The yield of compound 3C relative to compound 1C-1 was 57%. Thus, it was confirmed that sulfonic acid esters can be produced in good yield by the method described in Example 1-1.

[0154]

[0155] NMR spectrum of compound 3C: １ H-NMR: 4.96 ppm (-CH ２ -, 4H, s). １９ F-NMR: -70.0ppm (-CF ２ -, 4F, ddd, J=8, 14, 25Hz), -90.8ppm (CF ２ =CF-, 2F, tdd, J=8, 38, 52Hz), -103.6ppm (CF ２ =CF-, 2F, tdd, J=25, 52, 115Hz), -191.3ppm (CF ２ =CF-, 2F, tdd, J=14, 38, 115Hz).

[0156] [Example 1-2] 5 g of compound 1A-1 and 38 g of acetonitrile were placed in a 100 mL stainless steel autoclave. After freezing and degassing the inside of the autoclave, the internal temperature was maintained at 0°C while CF ２ =CH ２ 4g of was introduced. After introduction was complete, the internal temperature was maintained at 25°C and the reaction was continued for 3 hours, but no decrease in the internal pressure of the autoclave was observed. After the reaction was completed, the unreacted CF ２ =CH ２ The autoclave was purged and opened. The solution inside the autoclave was then... １ Analysis by 1H-NMR revealed that compound 1A-1 was not consumed, and compound 3X was not formed.

[0157]

[0158] [Example 1-3] 10.1 g of compound 1C-1 was placed in a 100 mL four-neck flask equipped with a stirrer, condenser, thermometer, and dropping funnel, under a nitrogen gas seal. 70 mL of acetonitrile was added, and the flask was cooled with ice. While maintaining the internal temperature at 0-5°C, H ３ CO-SO ２ - OCH ３ 7.82 g of was added dropwise. After the addition was complete, the internal temperature was maintained at 0-5°C and the reaction was allowed to proceed for 24 hours. After the reaction was complete, the precipitated white solid was removed by filtration, and a colorless, transparent filtrate was collected. １Analysis by H-NMR revealed that H ３ CO-SO ２ - OCH ３ It was confirmed that it contained 7.60 g of [compound name]. Compound 3Y was not formed.

[0159]

[0160] [Example 1-4] 1.00 g of compound 1A-1 was placed in a 100 mL four-neck flask equipped with a stirrer, condenser, thermometer, and dropping funnel, under a nitrogen gas seal. 40 mL of acetonitrile was added, and CF ２ = CF - CF ２ - OSO ２ 2.39 g of F was added dropwise. After the addition was complete, the internal temperature was maintained at 25°C and the reaction was allowed to proceed for 20 hours. After the reaction was complete, the precipitated white solid was removed by filtration, and the filtrate was concentrated by evaporation. The concentrated slightly yellowish oil was then... １ H-NMR and １９ Analysis by F-NMR revealed that the system contained a complex mixture, making it impossible to identify the target substance.

[0161]

[0162] [Example 2] 8.63 g of compound 3C was placed in a 100 mL four-necked flask equipped with a stirrer, condenser, thermometer, and dropping funnel, under a nitrogen gas seal. 42.7 g of acetonitrile was added, and the flask was cooled with ice. While maintaining the internal temperature at 0-5°C, 4.61 g of sodium fluoride was added. After the addition was complete, the internal temperature was maintained at 0-5°C and the reaction was allowed to proceed for 20 hours. After the reaction was complete, the solid components in the reaction solution were filtered off, and the filtrate was concentrated by evaporation. 30 mL of toluene was added to the concentrated yellowish oil, and after heating to 130°C, insoluble components were removed by filtration. The filtrate was transferred to a 100 mL separable flask, and after sealing the gas phase with nitrogen gas, it was allowed to cool for 14 hours, at which point a white powder precipitated. The powder was washed with toluene and dried again under a nitrogen gas stream. The dried solid was １ H-NMR and １９ Analysis by F-NMR confirmed the formation of 2.46 g of compound 5C with a purity of 99% by mass. The yield of compound 5C relative to compound 3C was 77%.

[0163]

[0164] NMR spectrum of compound 5C: １ H-NMR: 4.97 ppm (-CH ２ -, 4H, d, J = 3.1Hz). １９ F-NMR: 62.4 ppm (-SO ２ F, 2F, t, J = 3.1Hz). １３ C-NMR: 60.7 ppm (-CH ２ -), 184.9 ppm (C=O).

[0165] [Example 3] <Preparation of Compound 6C> 9.93 g of Compound 5C and 89.7 g of acetonitrile were placed in a 200 mL nickel autoclave. The autoclave was cooled, and nitrogen gas was blown in at a flow rate of 6.7 L / h while maintaining the internal temperature at 0-5°C, and the reaction mixture was bubbled for 1 hour. Subsequently, a mixture of fluorine gas and nitrogen gas (mixing ratio = 10.3 mol% / 89.7 mol%) was circulated at a flow rate of 6.7 L / h for 6 hours while maintaining the internal temperature at 0-5°C. Nitrogen gas was blown in again at a flow rate of 6.7 L / h, and the reaction mixture was bubbled for 1 hour. The autoclave was opened, and 103.2 g of the reaction mixture was recovered. １９ Analysis by F-NMR confirmed that the mixture contained 8.4% by mass of compound 6C and 3.2% by mass of hydrogen fluoride. The reaction yield of compound 6C relative to compound 5C was 66%.

[0166]

[0167] NMR spectrum of compound 6C: １９ F-NMR: 45.8 ppm (-SO ２ F, 2F, s), -104.1ppm (-CF ２ -, 4F, s).

[0168] <Preparation of Compound 7C> In a 50 mL four-necked flask equipped with a stirrer, condenser, thermometer, and dropping funnel, 1.65 g of potassium fluoride and 7.8 mL of diethylene glycol dimethyl ether were charged under nitrogen gas seal. The flask was cooled with ice, and while maintaining the internal temperature at 0-10°C, 8.43 g of the reaction solution obtained in the preparation of Compound 6C was added dropwise over 15 minutes. After the addition was complete, the internal temperature was maintained at 15-20°C and the reaction was allowed to proceed for 1 hour. The flask was cooled with ice again, and while maintaining the internal temperature at 0-10°C, CF ２ = CF - CF ２ - OSO ２ 6.56 g of F was added dropwise. After the addition was complete, the internal temperature was maintained at 25°C and the reaction was allowed to proceed for 3.5 hours. After the reaction was complete, the solid components in the reaction solution were filtered off, and 37.1 g of the filtrate was recovered. １９ Analysis by F-NMR confirmed the presence of 2.04% by mass of compound 7C. The reaction yield of compound 7C relative to compound 6C was 46.6%.

[0169]

[0170] NMR spectrum of compound 7C: １９ F-NMR: 46.8 ppm (-SO ２ F, 2F, s), -67.5ppm (-CF ２ -O-, 2F, m), -87.6ppm (CF ２ =CF-, 1F, ddt, J=7, 38, 49Hz), -101.5ppm (CF ２ =CF-, 1F, ddt, J=27, 49, 116Hz), -103.1ppm (-CF ２ -SO ２ F, 4F, m), -133.8ppm (-O-CF-, 1F, tt, J=6, 21Hz), -191.5ppm (CF ２ =CF-, 1F, ddt, J=14, 38, 116Hz).

[0171] [Example 4] 70.0 g of compound 7C was placed in a 100 mL stainless steel autoclave, and after freeze-degassing, 2.53 g of TFE was introduced into the autoclave and the internal temperature was heated to 100°C. At this time, the internal pressure was 0.29 MPaG. A mixture of 36.3 mg of PFtBPO, a polymerization initiator, and 2.58 g of HFC-52-13p was introduced into the autoclave through the injection line. Nitrogen gas was then introduced through the injection line to completely push in the mixture remaining in the injection line. This operation increased the internal pressure to 0.56 MPaG. Polymerization was carried out by continuously adding TFE to maintain the internal pressure at 0.56 MPaG. After 9.5 hours, when the amount of TFE added reached 4.03 g, the autoclave was cooled to stop the polymerization, and any remaining gaseous components in the system were purged. The reaction solution was diluted with HFC-52-13p, then HFE-347pc-f was added to agglomerate the polymer, and the mixture was filtered. Subsequently, the polymer was stirred in HFC-52-13p, and the process of re-aggregating with HFE-347pc-f was repeated twice. The recovered polymer was vacuum-dried at 120°C to obtain polymer F. The composition ratio, TQ value, and Tg of polymer F were as follows: Composition ratio: TFE units / compound 7C units = 86.2 mol% / 13.8 mol% TQ value: 238 [°C] Tg: 39 [°C]

[0172] [Example 5] Polymer F was press-molded at a temperature 10°C higher than the TQ value and at 4 MPaG to obtain a polymer F film (film thickness 100-250 μm). The polymer F film was immersed in an alkaline aqueous solution of potassium hydroxide / water = 20% by mass / 80% by mass at 80°C for 16 hours to obtain the -SO4 of polymer F. ２ The F group is hydrolyzed, and -SO ３ The polymer was converted to the K group. It was then immersed in a 3 mol / L hydrochloric acid solution at 50°C for 30 minutes, followed by immersion in ultrapure water at 80°C for 30 minutes. The cycle of immersion in hydrochloric acid solution and ultrapure water was repeated five times to convert the polymer to the -SO group. ３ K group -SO ３The polymer was converted to an H group. Subsequently, the polymer film was repeatedly washed with ultrapure water until the pH of the water in which it was immersed reached 7. The polymer film was sandwiched between filter paper and air-dried to obtain a polymer H film. The ion exchange capacity, softening temperature, 120°C modulus, conductivity, and water content of polymer H were as follows: Ion exchange capacity: 1.87 [milliequivalents / g dry resin] Softening temperature: 147 [°C] 120°C modulus: 95.7 [MPa] Conductivity: 0.136 [S / cm] Water content: 136 [%]

[0173] [Example 6] 4.3 g of finely cut polymer H film was placed in a 100 mL polytetrafluoroethylene (PTFE) container, 75 g of ultrapure water was added, and the mixture was heated at 200°C for 24 hours. The contents were transferred to a PTFE tray and air-dried at 30°C for 64 hours under a nitrogen atmosphere. The dried polymer H was transferred to a 200 mL glass autoclave, and 21.4 g of a mixed solvent of ultrapure water / ethanol (50% by mass / 50% by mass) was added. After stirring at 110°C for 25 hours, 3.87 g of ultrapure water was added to dilute it. After stirring at 90°C for 5 hours, it was allowed to cool, and 31.9 g of liquid composition S was obtained in which polymer H was dispersed in the mixed solvent at 13.5% by mass using a pressure filter (filter paper: Advantec Toyo Co., Ltd., PF040). Using an E-type viscometer, the shear rate was 76.6 s. －１ The viscosity at 25°C was measured to be 167 mPa·s.

[0174] [Example 7] A liquid composition S was coated onto a 100 μm ethylene-tetrafluoroethylene copolymer (ETFE) sheet using a die coater to form a film. This film was dried at 80°C for 15 minutes, and then heat-treated at 185°C for 30 minutes to obtain a solid polymer electrolyte film consisting of a polymer H film (film thickness 25 μm). The softening temperature, conductivity, and water content of the solid polymer electrolyte film were as follows: Softening temperature: 151 [°C] Conductivity: 0.132 [S / cm] Water content: 152 [%]

[0175] [Example 8] <Preparation of coating liquid for cathode catalyst layer formation> 4.2 g of platinum-supported carbon (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd., TEC10E50E) was mixed with 25.8 g of water and 16.9 g of ethanol. 12.8 g of liquid composition S was added to this mixture so that the I / C (ratio of the mass of polymer H to the mass of carbon in the platinum-supported carbon) was 0.8. The mixture was dispersed using a planetary ball mill (manufactured by Ito Seisakusho, model: LP-4) with 5 mm zirconia beads at a rotation speed of 300 rpm for a dispersion time of 180 minutes to obtain a coating liquid for cathode catalyst layer formation (composition for cathode catalyst layer formation) C.

[0176] <Preparation of coating liquid for anode layer formation> Polymer F', a copolymer of TFE and PSVE, was obtained by the method described in Production Example 4 of Japanese Patent Publication No. 2018-55877. The composition ratio and TQ value of polymer F' were as follows: Composition ratio: TFE units / PSVE units = 82.3 mol% / 17.7 mol% TQ value: 225 [°C]

[0177] Using polymer F' as a raw material, a liquid composition S' (solid content concentration = 26.0% by mass, ethanol / water = 60% by mass / 40% by mass) was obtained in which an acid-type sulfonic acid group-containing polymer (hereinafter referred to as "polymer H'") having an ion exchange capacity of 1.10 milliequivalents / g dry resin was dispersed by the method described in Example 4 of Japanese Patent Application Publication No. 2018-55877.

[0178] Instead of liquid composition S, liquid composition S' was used, and 3.0 g of platinum-supported carbon (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd., TEC10E50E) was mixed with 21 g of water and 9 g of ethanol. A coating liquid for forming an anode catalyst layer (composition for forming an anode catalyst layer) C' was obtained in the same manner as in Example 6-1, except that 12 g of liquid composition S' was added to this mixture so that the I / C ratio was 0.8.

[0179] <Manufacturing of Membrane Electrode Assembly> As the solid polymer electrolyte membrane, SO2 is a copolymer of TFE and PSVE. ２ F group SO ３A 25 μm thick ion exchange membrane (ion exchange capacity: 1.25 mm equivalent / g dry resin) was prepared from a polymer having acid-type sulfonic acid groups converted to H groups. A coating solution C for forming a cathode catalyst layer was applied to the above solid polymer electrolyte membrane with a platinum content of 0.2 mg / cm². ２ The film was coated with a die coater, dried at 80°C for 10 minutes, and then heat-treated at 150°C for 15 minutes to obtain a solid polymer electrolyte film with a cathode catalyst layer formed on one side. Next, a coating solution C' for forming the anode catalyst layer was applied to the ETFE sheet with a platinum content of 0.4 mg / cm². ２ The film was coated with a die coater, dried at 80°C for 10 minutes, and then heat-treated at 150°C for 15 minutes to obtain the anode catalyst layer. The solid polymer electrolyte membrane side of the solid polymer electrolyte membrane on which the cathode catalyst layer was formed and the anode catalyst layer were superimposed and pressed together at 160°C / 3.0 MPa (absolute pressure). By peeling off the ETFE sheet, which is the substrate of the anode catalyst layer, a film electrode assembly (electrode area: 25 cm²) was obtained. ２ ) was obtained.

[0180] Furthermore, the entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2024-190520, filed on October 30, 2024, are incorporated herein by reference as disclosure of the present invention.

Claims

1. A method for producing a sulfonic acid ester, comprising reacting a compound represented by formula (1) with a compound represented by formula (2) to obtain a compound represented by formula (3). R-(SO ２ O － Z ＋ )( ｎ (1) CFX = CF - CF ２ -Y (2) R-(SO ２ O - CFX - CF = CF ２ )( ｎ (3) In formula (1), formula (2) and formula (3), R is an n-valent aliphatic hydrocarbon group which may have an aromatic hydrocarbon group as a substituent. The aliphatic hydrocarbon group may have an etheric oxygen atom or -CO- between carbon atom-carbon atom bonds. Z ＋ is a monovalent cation. n is an integer of 1 to 4. X is a hydrogen atom or a halogen atom. Y is a monovalent leaving group.

2. In formulas (1) and (3) above, R is -(CH ２ ) ｍ１ -CO-(CH ２ ) ｍ２ A method for producing a sulfonic acid ester according to claim 1, wherein the group is represented by - and n is 2. In the above formula, m1 and m2 are each independently integers from 1 to 3.

3. In equations (1), (2), and (3) above, R is -CH ２ -CO-CH ２ -, n is 2, X is a fluorine atom, and Y is -OSO ２ A method for producing a sulfonic acid ester according to claim 1, wherein F.

4. A method for producing a sulfonic acid ester according to claim 1, wherein, before reacting the compound represented by formula (1) with the compound represented by formula (2), the compound represented by formula (1A) is mixed with a base or salt to obtain the compound represented by formula (1). R-(SO ２ OH) ｎ (1A) In equation (1A), R and n are the same as R and n in equation (1) above.

5. A method for producing a fluorosulfonyl group-containing compound, characterized by obtaining a compound represented by formula (3) by a manufacturing method described in any one of claims 1 to 4, and reacting the compound represented by formula (3) with an alkali metal fluoride to obtain a compound represented by formula (5). R-(SO ２ F) ｎ (5) In equation (5), R and n are the same as R and n in equation (3) above.

6. A method for producing a fluorosulfonyl group-containing compound, characterized by obtaining a compound represented by formula (3) by the manufacturing method described in claim 2; reacting the compound represented by formula (3) with an alkali metal fluoride to obtain a compound represented by formula (5B); fluorinating the compound represented by formula (5B) to obtain a compound represented by formula (6B); and reacting the compound represented by formula (6B) with a compound represented by formula (2B) to obtain a compound represented by formula (7B). FSO ２ - (CH ２ ) ｍ１ -CO-(CH ２ ) ｍ２ -SO ２ F (5B) FSO ２ - (CF ２ ) ｍ１ -CO-(CF ２ ) ｍ２ -SO ２ F (6B) CF ２ = CF - CF ２ - OSO ２ F (2B) CF ２ = CF - CF ２ -O-CF[(CF ２ ) ｍ１ -SO ２ F] [(CF ２ ) ｍ２ -SO ２ F] (7B) In equations (5B), (6B), and (7B), m1 and m2 are each independent integers between 1 and 3.

7. A method for producing a fluorosulfonyl group-containing compound according to claim 6, wherein in formulas (5B), (6B), and (7B), m1 and m2 are 1.

8. A method for producing a polymer, characterized by obtaining a compound represented by formula (7B) by the manufacturing method described in claim 6, and polymerizing a monomer containing the compound represented by formula (7B) to obtain a polymer having units based on the compound represented by formula (7B).

9. The method for producing a polymer according to claim 8, wherein in formula (7B), m1 and m2 are each 1.

10. A method for producing a polymer according to claim 8, comprising subjecting a polymer having units based on the compound represented by formula (7B) to hydrolysis to obtain a polymer having units represented by formula (8B). In formula (8B), m1 and m2 are the same as m1 and m2 in formula (7B), respectively.

11. The method for producing a polymer according to claim 10, wherein in formula (8B), m1 and m2 are each 1.

12. A method for producing a liquid composition, characterized by obtaining a polymer having units represented by formula (8B) by the manufacturing method described in claim 10, and mixing the polymer having units represented by formula (8B) with a liquid medium to obtain a liquid composition.

13. A method for producing a film, characterized by obtaining the liquid composition by the manufacturing method described in claim 12, and obtaining a film using the liquid composition.

14. A method for manufacturing a membrane electrode assembly comprising an anode having a catalyst layer, a cathode having a catalyst layer, and a solid polymer electrolyte membrane disposed between the anode and the cathode, characterized in that: the liquid composition is obtained by the manufacturing method described in claim 12; the liquid composition and a catalyst are mixed to obtain a catalyst layer forming composition; and the catalyst layer of at least one of the anode and the cathode is obtained using the catalyst layer forming composition.

15. Compound represented by formula (3): R-(SO ２ O-CFX-CF=CF ２ ) ｎ (3) In formula (3), R is an n-valent aliphatic hydrocarbon group which may have an aromatic hydrocarbon group as a substituent. The aliphatic hydrocarbon group may have an etheric oxygen atom or -CO- between the carbon-carbon bonds. n is an integer from 1 to 4. X is a hydrogen atom or a halogen atom.

16. In the above equation (3), R is -(CH ２ ) ｍ１ -CO-(CH ２ ) ｍ２ The compound according to claim 15, wherein the group is represented by - and n is 2. In the above formula, m1 and m2 are each independently integers from 1 to 3.

17. In equation (3) above, R is -CH ２ -CO-CH ２ The compound according to claim 15, wherein n is 2.

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