JP2008288097A - Membrane-electrode structure for polymer electrolyte fuel cell - Google Patents

Abstract

A membrane-electrode for a polymer electrolyte fuel cell comprising a proton conductive membrane that solves the problems of conventional fluorine-based electrolyte membranes and aromatic electrolyte membranes and has excellent heat resistance and proton conductivity Provide a structure.
A solid polymer type having excellent heat resistance and proton conductivity by using a sulfonated polyarylene obtained from a monomer having a nitrogen-containing heterocycle containing a sulfonic acid group in the side chain as a proton conductive membrane. A membrane-electrode structure for a fuel cell can be provided.
[Selection figure] None

Description

  The present invention relates to a membrane-electrode structure for a polymer electrolyte fuel cell.

  A fuel cell is a power generation system having high power generation efficiency, low emissions, and low environmental burden. The battery has been in the limelight as the interest in global environmental protection and the departure from dependence on fossil fuels has increased in recent years. Fuel cells are expected to be installed in mobile phones and mobile PCs in place of small distributed power generation facilities, power generation devices as driving sources for moving objects such as automobiles and ships, or secondary batteries such as lithium ion batteries. ing.

  A polymer electrolyte fuel cell is provided with a pair of electrodes on both sides of a proton-conducting polymer electrolyte membrane, supplies pure hydrogen or reformed hydrogen gas as fuel to one electrode (fuel electrode), oxygen gas or An electromotive force is obtained by supplying air to the other electrode (air electrode) as an oxidant. In water electrolysis, hydrogen and oxygen are produced by electrolyzing water using a solid polymer electrolyte membrane to cause a reverse reaction of the fuel cell reaction.

However, actual fuel cells and water electrolysis have a problem that side reactions occur in addition to these main reactions. A typical example is a reaction for generating hydrogen peroxide (H ₂ O ₂ ), and radical species resulting from the hydrogen peroxide cause deterioration of the solid polymer electrolyte membrane.

  Conventionally, solid polymer electrolyte membranes are commercially available under the trade names Nafion (registered trademark, manufactured by DuPont), Aciplex (registered trademark, manufactured by Asahi Kasei Kogyo Co., Ltd.), and Flemion (registered trademark, manufactured by Asahi Glass Co., Ltd.). Perfluorosulfonic acid-based membranes have been frequently used from the viewpoint of excellent chemical stability.

  However, a perfluorosulfonic acid membrane such as Nafion has a problem that it is difficult to manufacture and is very expensive, which is a major obstacle to popularization in consumer applications such as fuel cell vehicles and household fuel cell power generation systems. ing. Moreover, since it has a large amount of fluorine atoms in the molecule, it has a problem of a heavy load on the environment with respect to disposal after use.

  In addition, the fuel cell has a lower membrane resistance and higher power generation output as the proton conductive membrane between the electrodes is thinner at higher temperatures. However, these perfluoro acid-based membranes have a heat distortion temperature of about 80 to 100 ° C. and creep resistance at a high temperature is very poor. Therefore, the power generation temperature when these membranes are used in a fuel cell is 80 ° C. or less. There is also a problem that power generation output is limited. Also, the stability of the film thickness when used for a long time is poor, and in order to prevent a short circuit between the electrodes, a certain degree of film thickness (50 μm or more) is necessary, and it is considered difficult to reduce the film thickness. Yes.

In order to solve such problems of perfluorosulfonic acid membranes, solid polymer electrolyte membranes that do not contain fluorine atoms, are cheaper, and have a heat-resistant main chain skeleton used for engineer plastics are currently available. Many studies have been conducted. For example, a polymer in which a main chain aromatic ring of polyarylene, polyether ether ketone, polyether sulfone, polyphenylene sulfide, polyimide, or polybenzazole is sulfonated has been proposed (for example, Non-Patent Document 1). To 3).
Polymer Preprints, Japan, Vol. 42, no. 7, p. 2490-2492 (1993) Polymer Preprints, Japan, Vol. 43, no. 3, p. 735-736 (1994) Polymer Preprints, Japan, Vol. 42, no. 3, p730 (1993)

  However, these sulfonated polymers of the main chain aromatic ring have high water absorption and poor hot water resistance, so that the introduction amount of hydrophilic groups such as sulfonic acid groups is limited. Moreover, it was a material with poor Fenton reagent resistance (hydroxy radical resistance), which is a measure of power generation durability. When these electrolyte membranes are exposed to a high temperature of 100 ° C. or higher for a long period of time, the sulfonic acid is eliminated and the proton conduction performance is lowered, or the other aromatic ring having no sulfonic acid group introduced is crosslinked. It had the problem of causing embrittlement. If the membrane becomes more brittle, the membrane may be broken (pinholes) during long-term power generation, and power generation may become impossible.

  The present invention has been made in view of the above problems, and its object is to solve the problems of conventional fluorine-based electrolyte membranes and aromatic-based electrolyte membranes, and to have excellent heat resistance and proton conductivity. An object of the present invention is to provide a membrane-electrode structure for a polymer electrolyte fuel cell including a proton conducting membrane.

  The inventors of the present invention have made extensive studies to solve the above problems. As a result, a solid polymer fuel excellent in heat resistance and proton conductivity can be obtained by using a sulfonated polyarylene obtained from a monomer having a nitrogen-containing heterocycle containing a sulfonic acid group in the side chain as a proton conductive membrane. It has been found that a membrane-electrode structure for a battery can be provided, and the present invention has been completed. More specifically, the present invention provides the following.

・・・（２）
［式（２）中、Ｙは、−ＣＯ−、−ＳＯ_２−、−ＳＯ−、−ＣＯＮＨ−、−ＣＯＯ−、−（ＣＦ_２）_ｌ−（ｌは、１〜１０の整数である）、及び−Ｃ（ＣＦ_３）_２−よりなる群から選ばれる少なくとも１種の構造を示す。Ｗは、直接結合、−ＣＯ−、−ＳＯ_２−、−ＳＯ−、−ＣＯＮＨ−、−ＣＯＯ−、−（ＣＦ_２）_ｌ−（ｌは、１〜１０の整数である）、−Ｃ（ＣＦ_３）_２−、−Ｏ−、及び−Ｓ−よりなる群から選ばれる少なくとも１種の構造を示す。Ｚは、直接結合、又は、−（ＣＨ_２）_ｌ−（ｌは、１〜１０の整数である）、−Ｃ（ＣＨ_３）_２−、−Ｏ−、−Ｓ−、−ＣＯ−、及び−ＳＯ_２−よりなる群から選ばれる少なくとも１種の構造を示す。Ｒ^２０は、−ＳＯ_３Ｈ、−Ｏ（ＣＨ_２）_ｈＳＯ_３Ｈ、又は−Ｏ（ＣＦ_２）_ｈＳＯ_３Ｈ（ｈは、１〜１２の整数）で表される置換基を少なくとも１個有する含窒素複素環を示す。ｐは０〜１０の整数を示し、ｑは０〜１０の整数を示し、ｒは１〜５の整数を示し、ｋは０〜４の整数を示す。］ (1) In a membrane-electrode structure for a polymer electrolyte fuel cell in which an anode electrode is provided on one side of a proton conducting membrane and a cathode electrode is provided on the other side, the proton conducting membrane is represented by the following general formula (2): A membrane-electrode structure for a polymer electrolyte fuel cell, comprising: a repeating unit represented by:

... (2)
Wherein (2), Y _{is, -CO -, - SO 2 -} , - SO -, - CONH -, - COO -, - (CF 2) l - (l is an integer of 1 to 10) And at least one structure selected from the group consisting of —C (CF ₃ ) ₂ —. W is a direct bond, —CO—, —SO ₂ —, —SO—, —CONH—, —COO—, — (CF ₂ ) ₁ — (l is an integer of 1 to 10), —C ( CF ₃ ) ₂ —, —O—, and —S— represent at least one structure selected from the group consisting of —S—. Z is a direct bond, or — (CH ₂ ) ₁ — (l is an integer of 1 to 10), —C (CH ₃ ) ₂ —, —O—, —S—, —CO—, and 1 shows at least one structure selected from the group consisting of —SO ₂ —. R ²⁰ represents at least one substituent represented by —SO ₃ H, —O (CH ₂ ) _h SO ₃ H, or —O (CF ₂ ) _h SO ₃ H (h is an integer of 1 to 12). The nitrogen-containing heterocycle which has one piece is shown. p shows the integer of 0-10, q shows the integer of 0-10, r shows the integer of 1-5, k shows the integer of 0-4. ]

  (2) The nitrogen-containing heterocycle is pyrrole, thiazole, isothiazole, oxazole, isoxazole, imidazole, imidazoline, imidazolidine, pyrazole, 1,3,5-triazine, pyridine, pyrimidine, pyridazine, pyrazine, indole, quinoline , Isoquinoline, bryne, tetrazole, tetrazine, triazole, carbazole, acridine, quinoxaline, quinazoline, indolizine, isoindole, 3H-indole, 2H-pyrrole, 1H-indazole, purine, phthalazine, naphthyridine, cinnoline, pteridine, carboline, feline Nanthridine, perimidine, phenanthroline, phenazine, phenalsazine, phenothiazine, furazane, phenoxazine, pyrrolidine, pyrroline, pyrazoline, (1) Description: A group derived from at least one compound selected from the group consisting of nitrogen-containing heterocycles consisting of zolidine, piperidine, piperazine, indoline, isoindoline, quinuclidine, and derivatives thereof. A membrane-electrode structure for a polymer electrolyte fuel cell.

・・・（３）
［式（３）中、Ａ及びＣは、それぞれ独立に、直接結合、−ＣＯ−、−ＳＯ_２−、−ＳＯ−、−ＣＯＮＨ−、−ＣＯＯ−、−（ＣＦ_２）_ｌ−（ｌは、１〜１０の整数である）、−Ｃ（ＣＦ_３）_２−、−（ＣＨ_２）_ｌ−（ｌは、１〜１０の整数である）、−Ｃ（ＣＲ’_２）_２−（Ｒ’は、炭化水素基、又は環状炭化水素基を示す）、−Ｏ−、及び−Ｓ−よりなる群から選ばれる少なくとも１種の構造を示す。Ｂは、独立に、酸素原子、又は硫黄原子を示す。Ｒ^１〜Ｒ^１６は、互いに同一でも異なっていてもよく、水素原子、フッ素原子、アルキル基、一部又は全部がハロゲン化されたハロゲン化アルキル基、アリル基、アリール基、ニトロ基、及びニトリル基よりなる群から選ばれる少なくとも１種の原子又は基を示す。ｓ及びｔは、それぞれ独立に０〜４の整数を示し、ｕは、０以上の整数を示す。］ (3) The membrane-electrode structure for a polymer electrolyte fuel cell according to (1) or (2), further having a repeating unit represented by the following general formula (3).

... (3)
Wherein (3), A and C are each independently a direct _{bond, -CO -, - SO 2 -} , - SO -, - CONH -, - COO -, - (CF 2) l - (l is , an integer of 1 to _{10), - C (CF 3)} 2 -, - (CH 2) l - (l is an integer of 1 to _{10), - C (CR '2} ) 2 - (R 'Represents a hydrocarbon group or a cyclic hydrocarbon group), at least one structure selected from the group consisting of —O— and —S—. B independently represents an oxygen atom or a sulfur atom. R ^{1 to} R ¹⁶ may be the same or different from each other, and are a hydrogen atom, a fluorine atom, an alkyl group, a halogenated alkyl group partially or wholly halogenated, an allyl group, an aryl group, a nitro group, and a nitrile. At least one atom or group selected from the group consisting of groups is shown. s and t each independently represent an integer of 0 to 4, and u represents an integer of 0 or more. ]

(4) Y represents —CO— or —SO ₂ —, and W and Z are each independently a direct bond, —CO—, —SO ₂ —, —O—, and —S—. Any one of (1) to (3), wherein at least one structure selected from the group consisting of p and q is an integer of 0 to 2 and r is an integer of 1 to 2 The membrane-electrode structure for a polymer electrolyte fuel cell as described.

(5) Substitution wherein R ²⁰ is represented by —SO ₃ H, —O (CH ₂ ) _h SO ₃ H, or —O (CF ₂ ) _h SO ₃ H (h is an integer of 1 to 12). Any one of (1) to (4), which is a group derived from at least one compound selected from the group consisting of pyridine, imidazole, triazole, and derivatives thereof having at least one group A membrane-electrode structure for a polymer electrolyte fuel cell.

  (6) The membrane-electrode for a polymer electrolyte fuel cell according to any one of (1) to (5), wherein an ion exchange capacity of the proton conducting membrane is 0.5 meq / g to 3 meq / g Structure.

  The membrane-electrode structure for a polymer electrolyte fuel cell according to the present invention uses a sulfonated polyarylene obtained from a monomer having a nitrogen-containing heterocyclic ring containing a sulfonic acid group in the side chain as a proton conductive membrane. Therefore, it is excellent in heat resistance and proton conductivity, and is excellent in toughness and mechanical strength. In addition, since the sulfonated polyarylene used in the present invention can easily control the amount of sulfonic acid groups introduced, it is a solid having good proton conductivity, toughness, and mechanical strength over a wide temperature range. A membrane-electrode structure for a polymer fuel cell is obtained.

  Hereinafter, embodiments of the present invention will be described in detail.

  The sulfonated polyarylene used as the proton conducting membrane of the membrane-electrode structure for a polymer electrolyte fuel cell according to the present invention is a polymer having a phenylene bond in the main chain and containing a sulfonic acid group in the side chain. It can be obtained by polymerizing an aromatic compound having a nitrogen-containing heterocycle.

・・・（１） <Aromatic compounds>
The aromatic compound used for the polymerization of the sulfonated polyarylene is represented by the following general formula (1).

... (1)

The formula (1), X represents a halogen atom except fluorine (chlorine, bromine, iodine), and at least one atom or group selected from the group consisting of -OSO ₂ Rb. Here, Rb represents an alkyl group, a fluorine-substituted alkyl group, or an aryl group. Specific examples include a methyl group, an ethyl group, a trifluoromethyl group, and a phenyl group.

In the above formula (1), Y represents —CO—, —SO ₂ —, —SO—, —CONH—, —COO—, — (CF ₂ ) ₁ — (l is an integer of 1 to 10). And at least one structure selected from the group consisting of —C (CF ₃ ) ₂ —. More preferably, Y is —CO— or —SO ₂ —.

In the above formula (1), W is a direct bond, —CO—, —SO ₂ —, —SO—, —CONH—, —COO—, — (CF ₂ ) ₁ — (l is an integer of 1 to 10) At least one structure selected from the group consisting of —C (CF ₃ ) ₂ —, —O—, and —S—. More preferably, W is a direct bond, —CO—, —SO ₂ —, —O—, —S—.

In the above formula (1), Z is a direct bond, or — (CH ₂ ) ₁ — (1 is an integer of 1 to 10), —C (CH ₃ ) ₂ —, —O—, —S. -, - CO-, and -SO ₂ - it represents at least one structure selected from the group consisting of. More preferably, Z is a direct bond, —O—, —CO—, or —SO ₂ —.

  In said formula (1), Ra shows a C1-C20 hydrocarbon group. More preferably, it is a hydrocarbon group having 4 to 20 carbon atoms. Specifically, methyl group, ethyl group, n-propyl group, iso-propyl group, tert-butyl group, iso-butyl group, n-butyl group, sec-butyl group, neopentyl group, cyclopentyl group, hexyl group, Cyclohexyl group, cyclopentylmethyl group, cyclohexylmethyl group, adamantyl group, adamantanemethyl group, 2-ethylhexyl group, bicyclo [2.2.1] heptyl group, bicyclo [2.2.1] heptylmethyl group, tetrahydrofurfuryl Group, a straight chain hydrocarbon group such as 2-methylbutyl group, 3,3-dimethyl-2,4-dioxolanemethyl group, cyclohexylmethyl group, adamantylmethyl group, bicyclo [2.2.1] heptylmethyl group, etc. And a hydrocarbon group having a cyclic hydrocarbon group, an alicyclic hydrocarbon group, and a 5-membered heterocyclic ring. Among these, n-butyl group, neopentyl group, tetrahydrofurfuryl group, cyclopentyl group, cyclohexyl group, cyclohexylmethyl group, adamantylmethyl group, and bicyclo [2.2.1] heptylmethyl group are preferable, and neopentyl group is more preferable. .

In the above formula (1), R ²⁰ is —SO ₃ Rc, —O (CH ₂ ) _h SO ₃ Rc, or —O (CF ₂ ) _h SO ₃ Rc (h is an integer of 1 to 12, Rc is And a nitrogen-containing heterocycle having at least one substituent represented by (C 1 -C 20 hydrocarbon group). This nitrogen-containing heterocyclic ring is derived from a nitrogen-containing heterocyclic compound having a nitrogen-containing heterocyclic ring. A nitrogen-containing heterocyclic compound is a cyclic compound containing nitrogen in addition to carbon atoms among organic compounds having a cyclic structure. Two or more nitrogen atoms may be included in the cyclic structure, and further, oxygen and sulfur may be included. Nitrogen-containing heterocyclic compounds include pyrrole, thiazole, isothiazole, oxazole, isoxazole, imidazole, imidazoline, imidazolidine, pyrazole, 1,3,5-triazine, pyridine, pyrimidine, pyridazine, pyrazine, indole, quinoline, isoquinoline , Brine, Tetrazole, Tetrazine, Triazole, Carbazole, Acridine, Quinoxaline, Quinazoline, Indolizine, Isoindole, 3H-indole, 2H-pyrrole, 1H-indazole, Purine, Phthalazine, Naphthyridine, Cinnoline, Pteridine, Carboline, Phenanthridine , Perimidine, phenanthroline, phenazine, phenalsazine, phenothiazine, furazane, phenoxazine, pyrrolidine, pyrroline, pyrazoline, Zorijin, piperidine, piperazine, indoline, isoindoline, quinuclidine, and the like. Of these, imidazole, pyridine, and triazole are preferable.

  In the above formula (1), Rc is more preferably a hydrocarbon group having 4 to 20 carbon atoms. Specifically, methyl group, ethyl group, n-propyl group, iso-propyl group, tert-butyl group, iso-butyl group, n-butyl group, sec-butyl group, neopentyl group, cyclopentyl group, hexyl group, Cyclohexyl group, cyclopentylmethyl group, cyclohexylmethyl group, adamantyl group, adamantanemethyl group, 2-ethylhexyl group, bicyclo [2.2.1] heptyl group, bicyclo [2.2.1] heptylmethyl group, tetrahydrofurfuryl Group, a straight chain hydrocarbon group such as 2-methylbutyl group, 3,3-dimethyl-2,4-dioxolanemethyl group, cyclohexylmethyl group, adamantylmethyl group, bicyclo [2.2.1] heptylmethyl group, etc. And a hydrocarbon group having a cyclic hydrocarbon group, an alicyclic hydrocarbon group, and a 5-membered heterocyclic ring. Among these, n-butyl group, neopentyl group, tetrahydrofurfuryl group, cyclopentyl group, cyclohexyl group, cyclohexylmethyl group, adamantylmethyl group, and bicyclo [2.2.1] heptylmethyl group are preferable, and neopentyl group is more preferable. .

  In said formula (1), p shows the integer of 0-10, More preferably, it is an integer of 0-4, More preferably, it is an integer of 0-2. q shows the integer of 0-10, More preferably, it is an integer of 0-4, More preferably, it is an integer of 0-2. r shows the integer of 1-5, More preferably, it is an integer of 1-3, More preferably, it is an integer of 1-2. k shows the integer of 0-4, More preferably, it is an integer of 0-3, More preferably, it is an integer of 0-2.

As a preferable combination of Y, W, Z, p, q, r, and k,
(I) p = 1, q = 0, r = 1, Y = —CO—, Z = —O—,
(Ii) a structure in which p = 1, q = 0, r = 1, Y = —CO—, and Z = —S—.
(Iii) p = 1, q = 1, r = 1, k = 1, Y = —CO—, W = —CO—, Z = —O—,
(Iv) p = 1, q = 1, r = 1, k = 1, Y = —CO—, W = —CO—, Z = —S—,
(V) a structure in which p = 1, q = 1, r = 1, k = 1, Y = -CO-, W = -CO-, Z = -CO-,
(Vi) a structure in which p = 1, q = 1, r = 1, k = 1, Y = —CO—, W = —SO ₂ —, Z = —O—,
(Vii) p = 1, q = 1, r = 1, k = 1, Y = —CO—, W = —SO ₂ —, Z = —CO— (viii) p = 0, q = 1, r = 1, k = 1, W = —CO—, Z = —O—,
(Ix) a structure in which p = 0, q = 1, r = 1, k = 0, W = —CO—, and Z = —O—.
(X) a structure in which p = 0, q = 1, r = 1, k = 1, W = —CO—, Z = —S—,
(Xi) p = 0, q = 1, r = 1, k = 0, W = —CO—, Z = —S—,
(Xii) a structure where p = 0, q = 0, r = 1, and Z = —CO—.
(Xiii) p = 1, q = 0, r = 1, Y = —CO—, Z = —CO—,
(Xiv) a structure where p = 0, q = 1, r = 1, k = 1, W = —CO—, Z = —CO—.
(Xv) p = 0, q = 0, r = 1, and a structure in which Z is a direct bond.

Specific examples of the aromatic compound represented by the general formula (1) include compounds having the following structures.

In addition, examples of the aromatic compound represented by the general formula (1) include a compound in which a chlorine atom is replaced with a bromine atom in each of the above compounds, a compound in which —CO— is replaced with —SO ₂ —, and the like. In addition, isomers having different bonding positions of chlorine atoms and bromine atoms are also included.

  The Ra group in the general formula (1) is derived from a primary alcohol, and the β carbon is a tertiary or quaternary carbon, which is excellent in stability during the polymerization process and produces sulfonic acid by deesterification. It is preferable at the point which does not cause the polymerization inhibition and bridge | crosslinking resulting from. Further, it is more preferable that these ester groups are derived from primary alcohol and the β-position is quaternary carbon.

  The aromatic compound may be a single compound or a mixture of a plurality of positional isomers.

  The aromatic compound represented by the general formula (1) can be synthesized, for example, by the following reaction.

・・・（１１）

・・・（１２） The compound represented by the following general formulas (11) and (12) can be synthesized by nucleophilic substitution reaction with a nitrogen-containing heterocyclic compound and then sulfonation using a sulfonating agent.

(11)

(12)

  In the above formulas (11) and (12), X, Y, W, p, q, and r are the same as the definitions shown in the above formula (1). X ′ is a halogen atom, preferably a fluorine atom or a chlorine atom, and more preferably a fluorine atom.

  Specific examples of the compound represented by the formula (11) include 2,4-dichloro-4′-fluorobenzophenone, 2,5-dichloro-4′-fluorobenzophenone, and 2,6-dichloro-4′-fluorobenzophenone. 2,4-dichloro-2'-fluorobenzophenone, 2,5-dichloro-2'-fluorobenzophenone, 2,6-dichloro-2'-fluorobenzophenone, 2,4-dichlorophenyl-4'-fluorophenylsulfone, 2,5-dichlorophenyl-4'-fluorophenylsulfone, 2,6-dichlorophenyl-4'-fluorophenylsulfone, 2,4-dichlorophenyl-2'-fluorophenylsulfone, 2,4-dichlorophenyl-2'-fluorophenyl Sulfone, 2,4-dichlorophenyl-2'-fluoro Enirusuruhon, and the like. Of these compounds, 2,5-dichlorophenyl-4'-fluorophenylsulfone and 2,5-dichloro-4'-fluorobenzophenone are preferable.

Specific examples of the compound represented by the formula (12) include the following structures.

Further, the compound represented by the general formula (12), compound chlorine atom is replaced with a bromine atom in the above compounds, -CO- is -SO 2 _- may also be mentioned compounds replaced the like. In addition, isomers having different bonding positions of chlorine atoms and bromine atoms are also included.

  A nitrogen-containing heterocyclic compound is a cyclic compound containing nitrogen in addition to carbon atoms among organic compounds having a cyclic structure. Note that two or more nitrogen atoms may be included in the cyclic structure, and further, oxygen and sulfur may be included. The nitrogen-containing heterocyclic compound has active hydrogen, and this active hydrogen is subjected to a substitution reaction with the group represented by X ′ of the compounds represented by the general formulas (11) and (12).

  Examples of nitrogen-containing heterocyclic compounds having active hydrogen include imidazole, imidazoline, pyrazole, pyrrole, pyrrolidine, pyrroline, pyrazolidine, pyrazoline, piperidine, piperazine, indole, isoindole, indazole, indoline, isoindoline, morpholine, triazole, tetrazole, Purine, carbazole, phenothiazine, phenoxazine, 2-hydroxypyridine, 3-hydroxypyridine, 4-hydroxypyridine, 2-hydroxypyrimidine, 2-mercaptopyridine, 3-mercaptopyridine, 4-mercaptopyridine, 3-hydroxyquinoline, 8 -Hydroxyquinoline, 2-mercaptopyrimidine, 2-mercaptobenzthiazole and the like.

  For example, in those having a hydroxy group or a mercapto group, hydrogen bonded to an oxygen or sulfur atom becomes active hydrogen, and a nitrogen-containing heterocyclic ring is introduced via an —O— or —S— bond. In addition, a hydrogen atom bonded to a nitrogen atom of a nitrogen-containing heterocyclic ring and a hydrogen atom bonded to an atom other than nitrogen of the heterocyclic ring are also active hydrogen. In this case, a direct bond is formed between the nitrogen-containing heterocycle and the nitrogen-containing heterocycle is introduced.

  Of these compounds, 2-hydroxypyridine, 3-hydroxypyridine, 4-hydroxypyridine, imidazole, and triazole are preferable.

  The reaction of the compounds represented by the general formulas (11) and (12) and the nitrogen-containing heterocyclic compound having active hydrogen is preferably performed in an organic solvent. Polar solvents such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, sulfolane, diphenyl sulfone, dimethyl sulfoxide are used. In order to accelerate the reaction, alkali metal, alkali metal hydride, alkali metal hydroxide, alkali metal carbonate, or the like is used. The ratio between the compounds represented by the general formulas (11) and (12) and the nitrogen-containing heterocyclic compound having active hydrogen is equal to or excessively added to the nitrogen-containing heterocyclic compound having active hydrogen. . Specifically, the nitrogen-containing heterocyclic compound having active hydrogen is used in an amount of 1 to 3 times, particularly 1 to 1.5 times, the compound represented by the general formulas (11) and (12). It is preferable.

  The reaction temperature is 0 ° C to 300 ° C, preferably 10 ° C to 200 ° C. The reaction time is 15 minutes to 100 hours, preferably 1 hour to 24 hours. The obtained product is preferably used after being purified by a method such as recrystallization.

・・・（１３）

・・・（１４） When p = 0 and q = 0, and Z is other than a direct bond, the compounds represented by the following general formulas (13) and (14) are reacted and then sulfonated using a sulfonating agent, or chloro It can also be synthesized by sulfonation.

(13)

(14)

In the above formulas (13) and (14), X and R ²⁰ are the same as defined in the above formula (1). In this case, pyridine, imidazole, and triazole are particularly preferable.

In the formula (14), Z ′ represents at least one structure selected from the group consisting of —COCl, —SO ₂ Cl, —COOH, —SO ₃ H, —COORd, —SO ₃ Rd, and —CHO. Show. Rd represents a hydrocarbon group having 1 to 20 carbon atoms, specifically, methyl group, ethyl group, n-propyl group, iso-propyl group, tert-butyl group, iso-butyl group, n-butyl. Group, sec-butyl group and the like. A methyl group and an ethyl group are preferred.

When Z ′ is —COCl or —SO ₂ Cl, the reaction catalyst is preferably aluminum chloride, iron chloride, trifluoroboron, or Nafion. In addition, the reaction may be performed without using a solvent or with a reaction solvent that does not react with a reactant or a catalyst. Sulfone, methanesulfonic acid, trifluoromethanesulfonic acid, polyphosphoric acid, diethyl ether, acetonitrile and the like are preferably used. The reaction temperature is -20 ° C to 300 ° C, preferably 10 ° C to 200 ° C. The reaction time is 15 minutes to 100 hours, preferably 1 hour to 24 hours. If necessary, the reaction may be carried out under high pressure conditions. The pressure is 1 to 10 atmospheres, preferably 1 to 5 atmospheres. The product is preferably used after being purified by a method such as recrystallization.

・・・（１５）

・・・（１６） When p = 0 and q = 0 and Z is a direct bond, after reacting the compounds represented by the following general formulas (15) and (16), sulfonation using a sulfonating agent or chlorosulfone Can also be synthesized.

... (15)

... (16)

In the above formulas (15) and (16), X and R ²⁰ are the same as defined in the above formula (1). In this case, pyridine, imidazole, and triazole are particularly preferable.

Z ″ is at least one structure selected from —H, —F, —Cl, —Br, —I, —B (OH) ₂ , —MgBr, —Li-n-butyl, and —Li-tert-butyl. X ″ represents a fluorine atom, a chlorine atom, a bromine atom activated by at least one selected from potassium carbonate, lithium carbonate, n-butyllithium and tert-butyllithium when Z ″ is —H, When at least one structure selected from iodine atoms is represented and Z ″ is —F, —Cl, —Br, —I, —B (OH) ₂ , —MgBr, —Li—n-butyl, —Li— It represents at least one structure selected from tert-butyl, and when Z ″ is —B (OH) ₂ , —MgBr, —Li-n-butyl, —Li-tert-butyl, —F, —Cl, — At least selected from Br and -I It represents one of the structure.

  Any reaction solvent may be used as long as it does not react with the reactants or the catalyst. For example, a chlorinated solvent such as dichloromethane, chloroform, 1,2-dichloroethane, chlorobenzene, dichlorobenzene or the like is used. Preferably, diethyl ether, tetrahydrofuran or the like is used. The reaction temperature is −30 ° C. to 300 ° C., preferably −20 ° C. to 100 ° C. The reaction time is 15 minutes to 100 hours, preferably 1 hour to 24 hours. If necessary during the reaction, the reaction may be performed under high pressure conditions. The pressure is 1 to 10 atmospheres, preferably 1 to 5 atmospheres. The product is preferably used after being purified by a method such as recrystallization.

  Next, the aromatic compound obtained by the above reaction is sulfonated. Examples of the sulfonating agent include sulfonating agents such as sulfuric acid, chlorosulfonic acid, fuming sulfuric acid, and anhydrous sulfuric acid. The reaction is performed so that the sulfonic acid group is introduced into the target aromatic ring by controlling the reactivity, reaction temperature, and reaction time of the sulfonating agent. A preferred sulfonating agent is chlorosulfonic acid or fuming sulfuric acid. The reaction temperature when using chlorosulfonic acid is preferably 80 to 130 ° C.

  Next, the obtained sulfonic acid is converted into acid chloride. In this reaction, thionyl chloride, phosphoryl chloride, phosphorus pentachloride and the like can be used. When chlorosulfonic acid is used as the sulfonating agent, this step can be omitted because it can be isolated in the form of acid chloride.

  Finally, an aromatic compound represented by the above general formula (1) is obtained by an esterification reaction with various alcohols. Examples of the alcohol include t-butyl alcohol, sec-butyl alcohol, isobutyl alcohol, n-butyl alcohol, n-pentyl alcohol, neopentyl alcohol, cyclopentyl alcohol, n-hexyl alcohol, cyclohexyl alcohol, heptyl alcohol, octyl alcohol, 2- Ethylhexyl alcohol, cyclopentylmethyl alcohol, adamantyl alcohol, cyclohexylmethyl alcohol, adamantylmethyl alcohol, tetrahydrofurfuryl alcohol, 2-methylbutyl alcohol, 3,3-dimethyl-2,4-dioxolane methyl alcohol, bicyclo [2.2.1 ] Linear hydrocarbon group such as heptyl alcohol and bicyclo [2.2.1] heptylmethyl alcohol, branched hydrocarbon , Alicyclic hydrocarbon group and the like. Among these, neopentyl alcohol, tetrahydrofurfuryl alcohol, cyclopentylmethyl alcohol, cyclohexylmethyl alcohol, adamantylmethyl alcohol, and bicyclo [2.2.1] heptylmethyl alcohol are preferable, and neopentyl alcohol is more preferable.

  In the esterification reaction, a base such as pyridine, triethylamine, tripropylamine, or trioctylamine is preferably present together.

<Sulfonated polyarylene>
The sulfonated polyarylene having a nitrogen-containing heterocyclic ring containing a sulfonic acid group in the side chain used in the present invention has a repeating unit (sulfonic acid unit) having a sulfonic acid group represented by the following general formula (I). . Specifically, it is a polymer represented by the following general formula (III).

・・・（Ｉ） [Sulfonic acid unit]

... (I)

In the general formula (I), Y, Z, W, p, q, r, k, and R ²⁰ are the same as the definition shown in the above formula (2).

  More preferably, the sulfonated polyarylene has the sulfonic acid unit and a repeating unit (hydrophobic unit) having no sulfonic acid group represented by the following general formula (II).

・・・（ＩＩ） [Hydrophobic unit]

... (II)

In the general formula (II), A and C are each independently a direct bond, or —CO—, —SO ₂ —, —SO—, —CONH—, —COO—, — (CF ₂ ) ₁ — (l is an integer of 1 to _{10), - C (CF 3)} 2 -, - (CH 2) l - (l is an integer of 1 to _{10), - C (CR '2} ) 2 -(R 'represents a hydrocarbon group or a cyclic hydrocarbon group), at least one structure selected from the group consisting of -O- and -S-. Here, specific examples of the structure represented by —C (CR ′ ₂ ) ₂ — in which R ′ is a cyclic hydrocarbon group include a cyclohexylidene group and a fluorenylidene group. Among these, a direct bond, or —CO—, —SO ₂ —, —C (CF ₃ ) ₂ —, —C (CR ′ ₂ ) ₂ — (R ′ is a hydrocarbon group or a cyclic hydrocarbon group. -O- is preferable.

In the general formula (II), B is independently an oxygen atom or a sulfur atom, preferably an oxygen atom. R ^{1 to} R ¹⁶ may be the same as or different from each other, and are a hydrogen atom, a fluorine atom, an alkyl group, a halogenated alkyl group partially or wholly halogenated, an allyl group, an aryl group, a nitro group, a nitrile group. At least one atom or group selected from the group consisting of: Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, an amyl group, a hexyl group, a cyclohexyl group, and an octyl group. Examples of the halogenated alkyl group include a trifluoromethyl group, a pentafluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, and a perfluorohexyl group. Examples of the allyl group include a propenyl group. Examples of the aryl group include a phenyl group and a pentafluorophenyl group.

  In said general formula (II), s and t show the integer of 0-4. u represents 0 or an integer of 1 or more, and the upper limit is usually 100, preferably an integer of 1 to 80.

Preferred values for the values of s and t and the structures of A, B, C, R ^{1 to} R ¹⁶ are as follows:
(I) s = 1, t = 1, and A is —C (CF ₃ ) ₂ —, or —C (CR ′ ₂ ) ₂ — (R ′ represents a hydrocarbon group or a cyclic hydrocarbon group) Wherein B is an oxygen atom, C is —CO— or —SO ₂ —, and R ^{1 to} R ¹⁶ are hydrogen atoms or fluorine atoms,
(Ii) a structure in which s = 1, t = 0, B is an oxygen atom, C is —CO— or —SO ₂ —, and R ^{1 to} R ¹⁶ are a hydrogen atom or a fluorine atom,
(Iii) s = 0, t = 1, and A is —C (CF ₃ ) ₂ —, or —C (CR ′ ₂ ) ₂ — (R ′ represents a hydrocarbon group or a cyclic hydrocarbon group) Wherein B is an oxygen atom, and R ^{1 to} R ¹⁶ are a hydrogen atom, a fluorine atom, or a nitrile group,
(Iv) s = 1, t = 1, 2 and A is —C (CF ₃ ) ₂ —, or —C (CR ′ ₂ ) ₂ — (R ′ represents a hydrocarbon group or a cyclic hydrocarbon group. A structure in which B is an oxygen atom, and R ^{1 to} R ¹⁶ are a hydrogen atom or a fluorine atom,
(V) s = 0, t = 1, 2 and A is —C (CF ₃ ) ₂ — or —C (CR ′ ₂ ) ₂ — (R ′ represents a hydrocarbon group or a cyclic hydrocarbon group. And a structure in which B is an oxygen atom and R ^{1 to} R ¹⁶ are a hydrogen atom, a fluorine atom, or a nitrile group.

・・・（ＩＩＩ） [Polymer structure]
The sulfonated polyarylene used in the present invention is specifically represented by the following general formula (III).

... (III)

In the general formula (III), A, B, C, W, Y, Z, k, p, q, r, s, t, u, R ²⁰ , and R ^{1 to} R ¹⁶ are each represented by the above general formula ( It is synonymous with A, B, C, W, Y, Z, k, p, q, r, s, t, u, R ²⁰ , and R ^{1 to} R ^{16 in} I) and (II). x and y represent molar ratios when x + y = 100 mol%.

  The sulfonated polyarylene used in the present invention contains 0.5 to 100 mol%, preferably 10 to 99, of the repeating structural unit represented by the general formula (2), that is, the unit x in the general formula (III). The repeating structural unit represented by the general formula (3), that is, the y unit in the general formula (III) is 99.5 to 0 mol%, preferably 90 to 0.00 mol. It is contained at a ratio of 001 mol%.

[Method for producing polymer]
For the production of the sulfonated polyarylene used in the present invention, for example, the following two methods A and B can be used.

(Method A)
For example, by the method described in JP-A No. 2004-137444, a monomer having a sulfonate group that can be a structural unit represented by the general formula (I) and a structural unit represented by the general formula (II) can be obtained. It can be synthesized by copolymerizing a monomer or oligomer, producing a polyarylene having a sulfonate group, deesterifying the sulfonate group, and converting the sulfonate group to a sulfonate group. it can.

(Method B)
For example, in the method described in JP-A No. 2001-342241, a monomer having a skeleton represented by the above general formula (I) and having no sulfonic acid group or sulfonic acid ester group, and the above general formula (II). It is also possible to synthesize by copolymerizing a monomer or oligomer that can be a structural unit, and sulfonating the copolymer using a sulfonating agent.

  The sulfonated polyarylene used in the present invention is preferably produced by the method shown in Method A.

・・・（４） The monomer having no sulfonic acid that can be a structural unit represented by the above general formula (I) that can be used in the above (Method B) is represented by the following general formula (4).

... (4)

  In the general formula (4), X, Y, Z, W, p, q, and r are the same as the definition shown in the general formula (1).

In the general formula (4), R ²¹ represents a nitrogen-containing heterocyclic ring, specifically, pyrrole, thiazole, isothiazole, oxazole, isoxazole, imidazole, imidazoline, imidazolidine, pyrazole, 1, 3, 5 -Triazine, pyridine, pyrimidine, pyridazine, pyrazine, indole, quinoline, isoquinoline, bromine, tetrazole, tetrazine, triazole, carbazole, acridine, quinoxaline, quinazoline, indolizine, isoindole, 3H-indole, 2H-pyrrole, 1H-indazole , Purine, phthalazine, naphthyridine, cinnoline, pteridine, carboline, phenanthridine, perimidine, phenanthroline, phenazine, phenalsazine, phenothiazine, furazane, phenoxazine, pi Examples include at least one compound selected from the group consisting of nitrogen-containing heterocycles composed of loridine, pyrroline, pyrazoline, pyrazolidine, piperidine, piperazine, indoline, isoindoline and quinuclidine, and derivatives thereof. Of these, imidazole, pyridine, and triazole are preferable.

Specific examples of the monomer represented by the general formula (4) include structures as shown below.

Examples of the monomer represented by the general formula (4) include a compound in which a chlorine atom is replaced with a bromine atom and a compound in which —CO— is replaced with —SO ₂ — in each of the above compounds.

  In order to obtain a sulfonated polyarylene, first, a monomer that can be a structural unit represented by the general formula (I) and a monomer or oligomer that can be a structural unit represented by the general formula (II) are copolymerized. To obtain a precursor polyarylene.

(Method C)
In the general formula (I), when R ³⁰ is an aromatic group having a substituent represented by —O (CH ₂ ) _p SO ₃ H or —O (CF ₂ ) _p SO ₃ H, For example, in the method described in Japanese Patent Application No. 2003-295974, a precursor monomer that can be a structural unit represented by the general formula (I) and a monomer that can be a structural unit represented by the general formula (II), or It can also be synthesized by copolymerizing with an oligomer and then introducing an alkyl sulfonic acid or a fluorine-substituted alkyl sulfonic acid.

  This copolymerization is carried out in the presence of a catalyst, and the catalyst used here is a catalyst system containing a transition metal compound. Examples of such a catalyst system include (i) a transition metal salt and a ligand compound (hereinafter referred to as “ligand component”), or a transition metal complex coordinated with a ligand (copper salt). And (ii) a reducing agent as an essential component, and a salt may be added to further increase the polymerization rate.

  Specific examples of these catalyst components, the use ratio of each component, the reaction solvent, concentration, temperature, time, and other polymerization conditions include the compounds described in JP-A-2001-342241.

  The sulfonated polyarylene can be obtained by converting the precursor polyarylene into a polyarylene having a sulfonic acid group. As this method, there are the following two methods.

(Method A)
A method of deesterifying a polyarylene having a sulfonate group of a precursor by a method described in JP-A-2004-137444.

(Method B)
A method of sulfonating a precursor polyarylene by a method described in JP-A No. 2001-342241.

  The ion exchange capacity of the sulfonated polyarylene represented by the above general formula (III) produced by the method as described above is usually 0.3 to 5 meq / g, preferably 0.5 to 3 meq / g, Preferably it is 0.8-2.8 meq / g. If it is less than 0.3 meq / g, the proton conductivity is low and the power generation performance is low. On the other hand, if it exceeds 5 meq / g, the water resistance may be significantly lowered, which is not preferable.

  The ion exchange capacity is, for example, a precursor monomer that can be a structural unit represented by the general formula (I), a monomer that can be a structural unit represented by the general formula (II), or the type of oligomer, and the use ratio. It can be adjusted by changing the combination.

  The molecular weight of the sulfonated polyarylene thus obtained is 10,000 to 1,000,000, preferably 20,000 to 800,000 in terms of polystyrene-equivalent weight average molecular weight by gel permeation chromatography (GPC).

  The sulfonated polyarylene may be used by containing an anti-aging agent, preferably a hindered phenol compound having a molecular weight of 500 or more. The durability as an electrolyte can be further improved by containing an anti-aging agent.

  Examples of hindered phenolic compounds that can be used in the present invention include triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) proonate] (trade name: IRGANOX 245), 1,6-hexanediol-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (trade name: IRGANOX 259), 2,4-bis- (n-octylthio) -6 -(4-Hydroxy-3,5-di-t-butylanilino) -3,5-triazine (trade name: IRGANOX 565), pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4 -Hydroxyphenyl) propionate] (trade name: IRGANOX 1010), 2,2-thio-diethylenebis [3- (3 -Di-t-butyl-4-hydroxyphenyl) propionate] (trade name: IRGANOX 1035), octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate) (trade name: IRGANOX 1076) ), N, N-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide) (IRGAONOX 1098), 1,3,5-trimethyl-2,4,6-tris (3 , 5-Di-t-butyl-4-hydroxybenzyl) benzene (trade name: IRGANOX 1330), Tris- (3,5-di-t-butyl-4-hydroxybenzyl) -isocyanurate (trade name: IRGANOX) 3114), 3,9-bis [2- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) Ropioniruokishi] -1,1-dimethylethyl] -2,4,8,10-spiro [5.5] undecane (trade name: Sumilizer GA-80), and the like.

  In this invention, it is preferable to use a hindered phenol type compound in the quantity of 0.01-10 mass parts with respect to 100 mass parts of sulfonated polyarylene.

[Film creation method]
A polymer electrolyte membrane can be obtained by, for example, a casting method in which the sulfonated polyarylene is mixed in an organic solvent and cast onto a substrate to form a film. Here, the substrate is not particularly limited as long as it is a substrate used in an ordinary solution casting method. For example, a substrate made of plastic, metal, or the like is used, and preferably a heat treatment such as a polyethylene terephthalate (PET) film. A substrate made of a plastic resin is used.

  The solvent for mixing the sulfonated polyarylene may be a solvent that dissolves the copolymer or a solvent that swells. For example, N-methyl-2-pyrrolidone, N, N-dimethylformamide, γ-butyrolactone, N , N-dimethylacetamide, dimethylsulfoxide, dimethylurea, dimethylimidazolidinone, acetonitrile, and other aprotic polar solvents, dichloromethane, chloroform, 1,2-dichloroethane, chlorobenzene, dichlorobenzene and other chlorinated solvents, methanol, ethanol Alcohols such as propanol, iso-propyl alcohol, sec-butyl alcohol, tert-butyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monoe Alkylene glycol monoalkyl ethers such as ether, acetone, methyl ethyl ketone, cyclohexanone, ketones such as γ- butyrolactone, tetrahydrofuran, solvents such as ethers 1,3-dioxane and the like. These solvents can be used alone or in combination of two or more. In particular, N-methyl-2-pyrrolidone (hereinafter also referred to as “NMP”) is preferably used in terms of solubility and solution viscosity.

  When a mixture of an aprotic polar solvent and another solvent is used as the solvent, the composition of the mixture is such that the aprotic polar solvent is 95 to 25% by mass, preferably 90 to 25% by mass, A solvent is 5-75 mass%, Preferably it is 10-75 mass% (however, total is 100 mass%). When the amount of the other solvent is within the above range, the effect of lowering the solution viscosity is excellent. In this case, the combination of the aprotic polar solvent and the other solvent is preferably NMP as the aprotic polar solvent and methanol having an effect of lowering the solution viscosity in a wide composition range as the other solvent.

  The polymer concentration of the solution in which the sulfonated polyarylene and the additive are dissolved is usually 5 to 40% by mass, preferably 7 to 25% by mass, although it depends on the molecular weight of the sulfonated polyarylene. If it is less than 5% by mass, it is difficult to form a thick film, and pinholes are easily generated. On the other hand, if it exceeds 40% by mass, the solution viscosity is too high to form a film, and surface smoothness may be lacking.

  The solution viscosity is usually 2,000 to 100,000 mPa · s, preferably 3,000 to 50,000 mPa · s, although it depends on the molecular weight, polymer concentration, and additive concentration of the sulfonated polyarylene. is there. If it is less than 2,000 mPa · s, the retention of the solution during film formation is poor and it may flow from the substrate. On the other hand, if it exceeds 100,000 mPa · s, the viscosity is too high to be extruded from the die, and it may be difficult to form a film by the casting method.

  After film formation as described above, when the obtained undried film is immersed in water, the organic solvent in the undried film can be replaced with water, and the amount of residual solvent in the resulting polymer electrolyte membrane is reduced. can do.

  In addition, after film formation, before immersing an undried film in water, you may predry an undried film. The preliminary drying is performed by holding the undried film at a temperature of usually 50 to 150 ° C. for 0.1 to 10 hours.

  When immersing an undried film (including a pre-dried film; the same shall apply hereinafter) in water, a batch method in which a single wafer is immersed in water may be used, and the film is formed on a substrate film (for example, PET). A continuous method may be used in which the laminated film is left as it is, or the film separated from the substrate is immersed in water and wound up. In the case of the batch method, in order to suppress the formation of wrinkles on the surface of the film after treatment, it is preferable to immerse the film in water by a method such as placing an undried film on a frame.

  The amount of water used in immersing the undried film in water is 10 parts by mass or more, preferably 30 parts by mass or more, more preferably 50 parts by mass or more with respect to 1 part by mass of the undried film. If the amount of water used is in the above range, the amount of residual solvent in the resulting proton conducting membrane can be reduced. In addition, the amount of residual solvent in the resulting polymer electrolyte membrane can be reduced by changing the water used for immersion or overflowing it so that the organic solvent concentration in the water is always kept below a certain level. It is effective for. Furthermore, in order to suppress the in-plane distribution of the amount of the organic solvent remaining in the polymer electrolyte membrane, it is effective to homogenize the concentration of the organic solvent in water by stirring or the like.

  The temperature of water when the undried film is immersed in water is usually in the range of 5 to 80 ° C., preferably 10 to 60 ° C., from the viewpoint of the replacement speed and ease of handling. The higher the temperature, the faster the substitution rate of the organic solvent and water, but the greater the amount of water absorbed by the film, so the surface state of the polymer electrolyte membrane obtained after drying may deteriorate. The film immersion time is usually in the range of 10 minutes to 240 hours, preferably 30 minutes to 100 hours, although it depends on the initial residual solvent amount, the amount of water used and the treatment temperature.

  When the undried film is immersed in water and dried as described above, a film with a reduced amount of residual solvent is obtained. The amount of residual solvent in the film thus obtained is usually 5% by mass or less. Further, depending on the immersion conditions, the amount of residual solvent in the obtained film can be set to 1% by mass or less. As such conditions, for example, the amount of water used is 50 parts by mass or more with respect to 1 part by mass of the undried film, the temperature of the water during immersion is 10 to 60 ° C., and the immersion time is 10 minutes to 10 hours. is there.

  After immersing the undried film in water as described above, the film is dried at 30-100 ° C, preferably 50-80 ° C, for 10-180 minutes, preferably 15-60 minutes, and then at 50-150 ° C. The film can be obtained by vacuum drying under reduced pressure of 500 mmHg to 0.1 mmHg for 0.5 to 24 hours.

  The polymer electrolyte membrane obtained by the method of the present invention has a dry film thickness of usually 10 to 100 μm, preferably 20 to 80 μm.

  In addition, by forming the polyarylene copolymer having the sulfonic acid ester group or the alkali metal salt of sulfonic acid into a film by the above-described method, and then performing an appropriate post-treatment such as hydrolysis or acid treatment. The polymer electrolyte membrane according to the present invention can also be produced. Specifically, a polyarylene copolymer having an alkali metal salt of a sulfonic acid is formed into a film by the method described above, and then the membrane is hydrolyzed or acid-treated to thereby obtain a sulfonic acid group-containing polymer. A polymer electrolyte membrane made of an arylene copolymer can be produced.

  Further, when producing the polymer electrolyte membrane, in addition to the sulfonated polyarylene, inorganic acids such as sulfuric acid and phosphoric acid, phosphate glass, tungstic acid, phosphate hydrate, β-alumina proton substitution product, proton Inorganic proton conductor particles such as an introduced oxide, an organic acid containing a carboxylic acid, an organic acid containing a sulfonic acid, an organic acid containing a phosphonic acid, an appropriate amount of water, or the like may be used in combination.

<Electrode>
The electrode of the membrane-electrode structure for a polymer electrolyte fuel cell according to the present invention comprises a catalyst metal particle or an electrode catalyst in which the catalyst metal particle is supported on a conductive support, and an electrode electrolyte. Other components such as carbon fiber, a dispersant, a water repellent may be included.

  The catalyst metal particles are not particularly limited as long as they have catalytic activity, but metal black composed of noble metal fine particles such as platinum black can be used. The conductive carrier for supporting the catalyst metal particles is not particularly limited as long as it has conductivity and appropriate corrosion resistance. Therefore, it is desirable to use carbon (carbon) as a main component. The catalyst carrier that constitutes the electrode not only supports the catalyst metal particles, but also must function as a current collector for taking out electrons to the external circuit or taking them in from the external circuit. When the electric resistance of the catalyst carrier is high, the internal resistance of the battery is increased, and as a result, the performance of the battery is lowered. For this reason, the electronic conductivity of the catalyst carrier contained in the electrode must be sufficiently high. That is, it can be used as long as it has sufficient electronic conductivity as an electrode catalyst carrier, and preferably a carbon material with fine pores is used. As the carbon material having developed pores, carbon black, activated carbon or the like can be preferably used. Examples of carbon black include channel black, furnace black, thermal black, and acetylene black. Activated carbon is obtained by carbonizing and activating materials containing various carbon atoms. It is also possible to include metal oxides, metal carbides, metal nitrides and polymer compounds having electronic conductivity. In addition, the main component said here means containing 60% or more of carbonaceous matter.

  Further, platinum or a platinum alloy is used as the catalytic metal particles supported on the conductive carrier. However, when a platinum alloy is used, stability and activity as an electrode catalyst can be further imparted. Platinum alloys include platinum group metals other than platinum (ruthenium, rhodium, palladium, osmium, iridium), cobalt, iron, titanium, gold, silver, chromium, manganese, molybdenum, tungsten, aluminum, silicon, rhenium, zinc, Further, an alloy of platinum and one or more selected from the group consisting of tin and platinum is preferable, and the platinum alloy may contain an intermetallic compound of a metal alloyed with platinum.

  The supported rate of platinum or platinum alloy (ratio of the mass of platinum or platinum alloy to the total mass of the supported catalyst) is preferably 20 to 80% by mass, particularly preferably 30 to 55% by mass. Within this range, high output can be obtained. If the loading rate is less than 20% by mass, sufficient output may not be obtained. If the loading rate exceeds 80% by mass, platinum or platinum alloy particles may not be supported on the carbon material serving as a carrier with good dispersibility.

  The primary particle diameter of platinum or platinum alloy is preferably 1 to 20 nm in order to obtain a highly active gas diffusion electrode. In particular, a large surface area of platinum or platinum alloy can be secured in terms of reaction activity. It is preferably ˜5 nm.

As the electrode electrolyte, an ion conductive polymer electrolyte (ion conductive binder) having a sulfonic acid group is suitably used. Usually, the supported catalyst is covered with the electrolyte, and protons (H ⁺ ) move through a path where the electrolyte is connected.

  As the ion conductive polymer electrolyte having a sulfonic acid group, a perfluorocarbon polymer represented by Nafion (registered trademark), Flemion (registered trademark), and Aciplex (registered trademark) is particularly preferably used. In addition to perfluorocarbon polymers, sulfonated products of vinyl monomers such as polystyrene sulfonic acid, polymers having sulfonic acid groups or phosphoric acid groups introduced into heat-resistant polymers such as polybenzimidazole and polyether ether ketone, Alternatively, an ion conductive polymer electrolyte mainly composed of an aromatic hydrocarbon compound such as a sulfonated polyarylene described in the present specification may be used.

  Moreover, it is preferable to contain the said ion conductive binder in the ratio of 0.1-3.0 by mass ratio with respect to catalyst particles, and it is preferable to contain especially in the ratio of 0.3-2.0. When the ion conductive binder ratio is less than 0.1, protons cannot be transmitted to the electrolyte membrane, and there is a fear that sufficient output cannot be obtained. When the ion conductive binder ratio exceeds 3.0, the ion conductive binder is not sufficient. May completely cover the catalyst particles, the gas cannot reach platinum, and there is a possibility that sufficient output cannot be obtained.

  As carbon fibers that can be added as necessary, rayon-based carbon fibers, PAN-based carbon fibers, lignin poval-based carbon fibers, pitch-based carbon fibers, vapor-grown carbon fibers, and the like can be used. Then, vapor growth carbon fiber is preferable. When carbon fiber is included, the pore volume in the electrode catalyst layer increases, so that the diffusibility of fuel gas and oxygen gas is improved, and flooding due to the generated water can be improved, and the power generation performance is improved. . The carbon fiber may be contained in one or both of the anode-side and cathode-side electrode catalyst layers.

  Examples of the dispersant include an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant. The said dispersing agent may be used individually by 1 type, or may be used in combination of 2 or more type. Among these, a surfactant having a basic group is preferable, an anionic or cationic surfactant is more preferable, and a surfactant having a molecular weight of 5,000 to 30,000 is more preferable. When the above dispersant is added to the electrode paste composition used for forming the electrode catalyst layer, the storage stability and fluidity are excellent, and the productivity during coating is improved.

  The membrane-electrode structure in the present invention may consist of only the anode catalyst layer, the proton conducting membrane, and the cathode catalyst layer. However, both the anode and cathode are electrically conductive such as carbon paper or carbon cloth outside the catalyst layer. More preferably, a gas diffusion layer made of a porous porous substrate is disposed. Since the gas diffusion layer also functions as a current collector, in this specification, when the gas diffusion layer is provided, the gas diffusion layer and the catalyst layer are collectively referred to as an electrode.

  In the polymer electrolyte fuel cell having the membrane-electrode structure of the present invention, a gas containing oxygen is supplied to the cathode, and a gas containing hydrogen is supplied to the anode. Specifically, for example, a separator in which a groove to be a gas flow path is formed is disposed outside both electrodes of the membrane-electrode structure, and the gas is flowed through the gas flow path to thereby form the membrane-electrode structure. Supply fuel gas.

  As a method for producing the membrane-electrode structure of the present invention, a method in which a catalyst layer is directly formed on an ion exchange membrane and sandwiched between gas diffusion layers as necessary, on a base material to be a gas diffusion layer such as carbon paper A method of forming a catalyst layer and bonding it to an ion exchange membrane, a method of forming a catalyst layer on a flat plate and transferring it to the ion exchange membrane, then peeling the flat plate and further sandwiching it with a gas diffusion layer if necessary Various methods can be employed.

  As a method for forming the catalyst layer, a dispersion obtained by dispersing a supported catalyst and a perfluorocarbon polymer having a sulfonic acid group in a dispersion medium (if necessary, a water repellent, a pore former, a thickener, A known method of adding a diluting solvent or the like to the ion exchange membrane, gas diffusion layer, or flat plate can be employed.

  Examples of the method for forming the electrode paste composition include brush coating, brush coating, bar coater coating, knife coater coating, doctor blade method, screen printing, and spray coating.

  When the catalyst layer is not directly formed on the ion exchange membrane, the catalyst layer and the ion exchange membrane are preferably joined by a hot press method, an adhesion method (see JP-A-7-220741) or the like.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to a following example. In this example, the sulfonated polymer film used for various measurements was manufactured by casting after dissolving the sulfonated polymer in an N-methylpyrrolidone / methanol solution. Further, various measurement items in the examples are determined as follows, and% means mass% unless otherwise specified.

[Mass average molecular weight]
The number average molecular weight (Mn) and the mass average molecular weight (Mw) of the polymer were determined as the polystyrene-reduced mass average molecular weight by gel permeation chromatography (GPC) using an NMP buffer solution as a solvent. The NMP buffer solution was adjusted at a ratio of NMP (3 L) / phosphoric acid (3.3 mL) / lithium bromide (7.83 g).

[Equivalent of sulfonic acid group]
The resulting sulfonated polymer was washed with distilled water until the washing water became neutral to remove free remaining acid, and then dried. Thereafter, a predetermined amount is weighed, dissolved in a mixed solvent of THF / water, titrated with a standard solution of NaOH using phenolphthalein as an indicator, and the equivalent of sulfonic acid groups (ion exchange capacity) from the neutral point. (Meq / g) was determined.

[Measurement of breaking strength and elastic modulus]
The breaking strength and elastic modulus were measured according to JIS K7113 (tensile speed: 50 mm / min). However, the elastic modulus was calculated with the distance between marked lines as the distance between chucks. According to JIS K7113, the condition of the sample was adjusted for 48 hours under conditions of a temperature of 23 ± 2 ° C. and a relative humidity of 50 ± 5%. However, the No. 7 dumbbell described in JIS K6251 was used for punching the sample. As the tensile test measurement device, 5543 manufactured by INSTRON was used.

・・・数式（１） [Measurement of proton conductivity]
The AC resistance was obtained by pressing a platinum wire (f = 0.5 mm) on the surface of a strip-shaped sample film having a width of 5 mm, holding the sample in a constant temperature and humidity device, and measuring AC impedance between the platinum wires. . That is, the impedance at AC 10 kHz was measured in an environment of 85 ° C. and relative humidity 90%. A chemical impedance measurement system manufactured by NF Circuit Design Block Co., Ltd. was used as the resistance measurement device, and JW241 manufactured by Yamato Scientific Co., Ltd. was used as the constant temperature and humidity device. Five platinum wires were pressed at intervals of 5 mm, the distance between the wires was changed to 5 to 20 mm, and the AC resistance was measured. From the distance between the lines and the resistance gradient, the specific resistance R of the membrane was calculated according to the following formula (1), and the proton conductivity was calculated from the reciprocal of the specific resistance.

... Formula (1)

・・・数式（２） [Heat resistance test]
A film cut to 2 cm × 3 cm was sandwiched between bencots, placed in a crow sample tube, and heated in a compact precision thermostat (AWC-2) at 160 ° C. for 24 hours under air conditions. The heated film was dissolved in NMP buffer solvent at a concentration of 0.2 wt%, and the molecular weight and area area (A24) were determined by GPC (NMP buffer solvent) (HCL-8220 manufactured by Tosoh Corporation). The film before heating was also measured under the same conditions, the molecular weight and area area (A0) were determined, and the insoluble fraction was determined according to the change in molecular weight and the following mathematical formula (2). The NMP buffer solution was adjusted at a ratio of NMP (3 L) / phosphoric acid (3.3 mL) / lithium bromide (7.83 g).

... Formula (2)

[Evaluation of power generation characteristics]
Using the membrane-electrode structure of the present invention, power generation performance was evaluated under power generation conditions of a temperature of 70 ° C., a fuel electrode side / oxygen electrode side relative humidity of 50% / 73%, and a current density of 1 A / cm ^2. did. Pure hydrogen was supplied to the fuel electrode side, and air was supplied to the oxygen electrode side. Furthermore, as an evaluation of power generation durability, a power generation durability test was performed using the membrane-electrode structure under the conditions of a temperature of 120 ° C., a relative humidity of the fuel electrode side / oxygen electrode side of 50% / 50%, and 0 CV. The time to cross leak was measured. The case where the time until the cross leak was 500 hours or more was indicated as “Good” as good, and the case where it was less than 500 hours was indicated as “Poor” as bad.

<Example 1>
[Synthesis of sulfonic acid unit]
2306.4 g (24 mol) of fluorobenzene was placed in a 2 L three-necked flask equipped with a stirring blade, a thermometer, and a nitrogen introduction tube, cooled to 10 ° C. in an ice bath, and 1005.4 g of 2,5-dichlorobenzoic acid chloride ( 4.8 mol) and 832.1 g (6.3 mol) of aluminum chloride were gradually added so that the reaction temperature did not exceed 40 ° C. After the addition, the mixture was stirred at 40 ° C. for 8 hours. After completion of the reaction, the reaction solution was added dropwise to ice water and extracted from ethyl acetate. The mixture was neutralized with 1% aqueous sodium hydrogen carbonate solution, washed with saturated brine, and concentrated. The following (30-1) was obtained by recrystallization from methanol. Yield was 1033 g.

  The following formula (30-1) 132.6.4 g (4.9 mol), 2-hydroxypyridine was added to a 7 L three-necked flask equipped with a stirrer, thermometer, cooling tube, Dean-Stark tube, and nitrogen-introduced three-way cock. 467.9 g (4.9 mol) and 748.0 g (5.4 mol) of potassium carbonate were taken, 5 L of N, N-dimethylacetamide (DMAc) and 1 L of toluene were taken, heated in an oil bath under a nitrogen atmosphere, and stirred. The reaction was carried out at 130 ° C. When water produced by the reaction was azeotroped with toluene and reacted while being removed from the system with a Dean-Stark tube, almost no water was observed in about 3 hours. Thereafter, most of the toluene was removed, and the reaction was continued at 130 ° C. for 10 hours. The resulting reaction solution was allowed to cool, and then the filtrate was put into 20 L of water / methanol (9/1). The precipitated product was filtered off, collected and dried. Take the dried product in a 7 L three-necked flask equipped with a stirrer, thermometer, cooling tube, Dean-Stark tube and nitrogen-introduced three-way cock, stir at 100 ° C. in 5 L of toluene, and distill off the remaining water. Dissolved. After allowing to cool, the crystallized product was filtered to obtain the desired product (30-2). Yield was 1300 g.

  The following formula (30-2) 585.1 g (1.7 mol) was dissolved in 387 g of concentrated sulfuric acid in a 5 L three-necked flask equipped with a stirrer, thermometer, condenser, and nitrogen-introduced three-way cock, and iced at 20 ° C. Chilled. 1062.5 g of fuming sulfuric acid (60%) was gradually added and stirred at 90 ° C. for 8 hours. After completion of the reaction, the reaction mixture was dissolved in ice and neutralized with an aqueous sodium hydroxide solution. The water was removed by concentration and dissolved in dimethyl sulfoxide. Insoluble matter was removed by filtration, and the soluble portion was concentrated. The compound (30-3) was obtained by dissolving in a small amount of dimethyl sulfoxide, coagulating in acetone, and filtering the solidified product. The yield was 745g.

  After dissolving 1054 g (1.9 mol) of the following (30-3) in 1 L of sulfolane in a 5 L three-necked flask equipped with a stirrer, thermometer, condenser, and nitrogen-introduced three-way cock, gradually add 920 g of phosphoryl chloride. It was dripped. After completion of the dropwise addition, the mixture was stirred at 70 ° C. for 8 hours, and then the reaction solution was dropped into ice and extracted with ethyl acetate. The mixture was neutralized with an aqueous sodium hydrogen carbonate solution, washed with saturated brine, and dried over magnesium sulfate. After concentrating the solvent, the objective compound (30-4) was obtained by coagulating in hexane. The yield was 373g.

The following (30-4) 324.7 g (0.6 mol) and neopentyl alcohol 105.8 g (1.2 mol) were dissolved in 378 g of pyridine in a 1 L three-necked flask equipped with a stirring blade, a thermometer, and a nitrogen inlet tube. The reaction was carried out at 5 to 10 ° C. for 8 hours. After completion of the reaction, the mixture was added dropwise to 1% hydrochloric acid / ice water, followed by extraction from ethyl acetate. The mixture was neutralized with 1% aqueous sodium hydrogen carbonate solution, washed with saturated brine, and concentrated. The following (30-5) was obtained by recrystallization from ethyl acetate / methanol. The yield was 193g.

[Synthesis of hydrophobic units]
To a 1 L three-necked flask equipped with a stirrer, thermometer, cooling pipe, Dean-Stark pipe and nitrogen-introduced three-way cock, 2,2-bis (4-hydroxyphenyl) -1,1,1,3 , 3,3-hexafluoropropane 67.3 g (0.20 mol), 4,4′-dichlorobenzophenone (4,4′-DCBP) 60.3 g (0.24 mol), potassium carbonate 71.9 g (0.52 mol) ), 300 mL of N, N-dimethylacetamide (DMAc) and 150 mL of toluene were taken and heated in an oil bath in a nitrogen atmosphere and reacted at 130 ° C. with stirring. When water produced by the reaction was azeotroped with toluene and reacted while being removed from the system with a Dean-Stark tube, almost no water was observed in about 3 hours. The reaction temperature was gradually increased from 130 ° C to 150 ° C. Thereafter, most of the toluene was removed while gradually raising the reaction temperature to 150 ° C., and the reaction was continued at 150 ° C. for 10 hours. Then, 10.0 g (0.040 mol) of 4,4′-DCBP was added, and another 5 hours. Reacted. The resulting reaction solution was allowed to cool, and then the by-product inorganic compound precipitate was removed by filtration, and the filtrate was put into 4 L of methanol. The precipitated product was separated by filtration, collected, dried, and dissolved in 300 mL of tetrahydrofuran. This was reprecipitated in 4 L of methanol to obtain 95 g (yield 85%) of the target compound.

・・・（３０−６） The Mn in terms of polystyrene determined by GPC (THF solvent) of the obtained compound was 11,200. The obtained compound was an oligomer of the following (30-6).

... (30-6)

[Synthesis of sulfonated polyarylene]
239 mL of dried DMAc was mixed with 62.27 g (96.6 mmol) of the compound represented by the above general formula (30-5) and 38.08 g (3.4 mmol) of the hydrophobic unit of the above (30-6), bis (triphenyl Phosphine) Nickel dichloride 3.27 g (5.0 mmol), triphenylphosphine 10.49 g (40 mmol), sodium iodide 0.45 g (3.0 mmol), zinc 15.69 g (240 mmol) was added under nitrogen. It was.

  The reaction system was heated with stirring (finally heated to 79 ° C.) and reacted for 3 hours. An increase in viscosity in the system was observed during the reaction. The polymerization reaction solution was diluted with 658 mL of DMAc, stirred for 30 minutes, and filtered using Celite as a filter aid.

・・・（３０−７） Lithium bromide (50.34 g, 579.6 mmol) was added to the filtrate, and the mixture was reacted at an internal temperature of 110 ° C. for 7 hours under a nitrogen atmosphere. After the reaction, the mixture was cooled to room temperature, poured into 3.5 L of water and solidified. The coagulum was immersed in acetone, filtered and washed. The washed product was washed with stirring with 1.7 kg of 1N sulfuric acid. After filtration, the product was washed with ion exchanged water until the pH of the washing solution became 5 or higher. As a result of measuring the molecular weight of the obtained polymer by GPC, Mn was 53,000 and Mw was 105,000. The ion exchange capacity was 2.28 meq / g. The obtained polymer was a polymer represented by the following general formula (30-7).

... (30-7)

[Production of proton conducting membrane]
The polymer obtained in this example was dissolved in N-methyl-2-pyrrolidone at a concentration of 14 to 16%, cast on a glass plate, and dried to obtain a film having a thickness of 40 μm.

[Production of membrane-electrode structure]
Platinum particles were supported on carbon black (furnace black) having an average diameter of 50 nm at a mass ratio of carbon black: platinum = 1: 1 to prepare catalyst particles. Next, in the perfluoroalkylenesulfonic acid polymer compound solution (Nafion (trade name) manufactured by Dupont) as an ion conductive binder solution, the previous catalyst particles are added in a mass ratio of ion conductive binder: catalyst particles = 8: 5. A catalyst paste was prepared by uniformly dispersing.

The catalyst paste is applied to both sides of the proton conductive membrane containing the sulfonated polyarylene obtained in this example by applying a bar coater so that the platinum content is 0.5 mg / cm ^2, and drying to apply an electrode. A membrane (Catalyst Coated Membrane) was obtained. The drying was performed at 100 ° C. for 15 minutes, followed by secondary drying at 140 ° C. for 10 minutes.

  Carbon black and polytetrafluoroethylene (PTFE) particles are mixed at a mass ratio of carbon black: PTFE particles = 4: 6, and a slurry in which the resulting mixture is uniformly dispersed in ethylene glycol is mixed on one side of carbon paper. It was applied and dried to form an underlayer, and two gas diffusion layers composed of the underlayer and carbon paper were produced.

  The CCM was sandwiched between the gas diffusion layer and the base layer side, and hot pressing was performed to obtain a membrane-electrode structure. The hot pressing was performed at 160 ° C. and 3 MPa for 5 minutes. Further, the membrane-electrode structure obtained in this example can constitute a solid polymer fuel cell by further laminating a separator that also serves as a gas passage on the gas diffusion layer.

<Example 2>
[Synthesis of hydrophobic units]
To a 1 L three-necked flask equipped with a stirrer, thermometer, Dean-stark tube, nitrogen inlet tube, and condenser tube, 154.8 g (0.9 mol) of 2,6-dichlorobenzonitrile and 2,2-bis (4-hydroxy) were added. (Phenyl) -1,1,1,3,3,3-hexafluoropropane (269.0 g, 0.8 mol) and potassium carbonate (143.7 g, 1.04 mol) were weighed. After substitution with nitrogen, 1020 mL of sulfolane and 510 mL of toluene were added and stirred. The reaction solution was heated to reflux at 150 ° C. in an oil bath. Water produced by the reaction was trapped in a Dean-stark tube. After 3 hours, when almost no water was observed, toluene was removed from the Dean-stark tube out of the system. The reaction temperature was gradually raised to 200 ° C. and stirring was continued for 3 hours. Then, 51.6 g (0.3 mol) of 2,6-dichlorobenzonitrile was added, and the reaction was further continued for 5 hours.

  The reaction solution was allowed to cool and then diluted by adding 250 mL of toluene. Inorganic salts insoluble in the reaction solution were filtered, and the filtrate was poured into 8 L of methanol to precipitate the product. The precipitated product was filtered and dried, then dissolved in 500 mL of tetrahydrofuran, and poured into 5 L of methanol for reprecipitation. The precipitated white powder was filtered and dried to obtain 258 g of the desired product. Mn measured by GPC was 7,500.

・・・（３０−８） It was confirmed that the obtained compound was an oligomer represented by the formula (30-8).

... (30-8)

[Synthesis of sulfonated polymer]
Example 1 except that 61.24 g (95.0 mmol) of the above (30-5), 37.50 g (5.0 mmol) of the above (30-8), and 49.50 g (570 mmol) of lithium bromide were used. Synthesis was performed in the same manner.

・・・（３０−９） As a result of measuring the molecular weight of the obtained polymer by GPC, Mn was 41,000 and Mw was 84,000. The ion exchange capacity was 2.30 meq / g. The obtained polymer was a polymer represented by the following general formula (30-9).

... (30-9)

[Production of proton conducting membrane]
The polymer obtained in this example was dissolved in N-methyl-2-pyrrolidone at a concentration of 14 to 16%, cast on a glass plate, and dried to obtain a film having a thickness of 40 μm.

[Production of membrane-electrode assembly]
A membrane-electrode assembly was obtained in the same manner as in Example 1 except that the proton conductive membrane obtained in this example was used.

<Example 3>
[Synthesis of hydrophobic units]
To a 1 L separable three-necked flask equipped with a stirring blade, a thermometer, a nitrogen introduction tube, a Dean-Stark tube, and a cooling tube, 42.4′-difluorobenzophenone 52.4 g (240 mmol), 4-chloro-4′-fluorobenzophenone 14.1 g (60.0 mmol), 4,4 ′-(1,3-phenylenediisopropylidene) bisphenol 70.2 g (203 mmol), bis (4-hydroxyphenyl) fluorene 23.7 g (67.5 mmol), carbonic acid 48.5 g (351 mmol) of potassium was weighed. DMAc 430mL and toluene 220mL were added, and it heated and refluxed at 150 degreeC by nitrogen atmosphere. The water produced by the reaction was removed from the Dean-Stark tube by azeotropy with toluene. When no more water was observed after 3 hours, toluene was removed from the system and stirred at 160 ° C. for 7 hours. Then, 7.0 g (20.0 mmol) of 4-chloro-4′-fluorobenzophenone was added, The mixture was further stirred for 3 hours.

・・・（３０−１０） After standing to cool, inorganic substances insoluble in the reaction solution were removed by filtration using Celite as a filter aid. The filtrate was poured into 2.0 L of methanol to solidify the reaction product. The precipitated coagulum was filtered, washed with a small amount of methanol, and vacuum dried. The dried product was redissolved in 200 mL of tetrahydrofuran. This solution was poured into 2.0 L of methanol and reprecipitated. The coagulated product was filtered and dried under vacuum to obtain 110 g (yield 80%) of the desired product. The polystyrene-converted Mn obtained by GPC was 6,000. It was confirmed that the obtained compound was an oligomer represented by the following formula (30-10).

... (30-10)

[Synthesis of sulfonated polymer]
Example 1 except that 60.46 g (93.8 mmol) of the above (30-5), 37.20 g (6.2 mmol) of the above (30-10), and 48.88 g (563 mmol) of lithium bromide were used. Synthesis was performed in the same manner.

・・・（３０−１１） As a result of measuring the molecular weight of the obtained polymer by GPC, Mn was 39,000 and Mw was 88,000. The ion exchange capacity was 2.29 meq / g. The obtained polymer was a polymer represented by the following general formula (30-11).

... (30-11)

[Production of proton conducting membrane]
The polymer obtained in this example was dissolved in N-methyl-2-pyrrolidone at a concentration of 14 to 16%, cast on a glass plate, and dried to obtain a film having a thickness of 40 μm.

[Production of membrane-electrode assembly]
A membrane-electrode assembly was obtained in the same manner as in Example 1 except that the proton conductive membrane obtained in this example was used.

<Example 4>
[Synthesis of hydrophobic units]
In a 3 L separable three-necked flask equipped with a stirring blade, a thermometer, a nitrogen introduction tube, a Dean-Stark tube, and a condenser tube, 207.81 g (952 mmol) of 4,4′-difluorobenzophenone, 4-chloro-4′-fluorobenzophenone 42 .46 g (181 mmol), resorcinol 103.8 g (943 mmol), bis (4-hydroxyphenyl) fluorene 36.7 g (105 mmol), and potassium carbonate 173.8 g (1.3 mol) were weighed. DMAc 1250mL and toluene 500mL were added, and it heated and refluxed at 150 degreeC by nitrogen atmosphere. The water produced by the reaction was removed from the Dean-Stark tube by azeotropy with toluene. When no more water was observed after 3 hours, toluene was removed from the system and stirred at 160 ° C. for 7 hours. Then, 12.3 g (52.0 mmol) of 4-chloro-4′-fluorobenzophenone was added, and Stir for 3 hours.

・・・（３０−１２）
After standing to cool, inorganic substances insoluble in the reaction solution were removed by filtration using Celite as a filter aid. The filtrate was poured into 5.0 L of methanol to solidify the reaction product. The precipitated coagulum was filtered, washed with a small amount of methanol, and vacuum dried. The dried product was redissolved in 810 mL of tetrahydrofuran. This solution was poured into 3.2 L of methanol and reprecipitated. The coagulated product was filtered and dried under vacuum to obtain 261 g (yield 75%) of the desired product. The Mn in terms of polystyrene determined by GPC was 4,000. It was confirmed that the obtained compound was an oligomer represented by the following formula (30-12).

... (30-12)

[Synthesis of sulfonated polymer]
Example 1 except that 58.59 g (90.9 mmol) of the above (30-5), 36.40 g (9.1 mmol) of the above (30-12), and 47.37 g (545 mmol) of lithium bromide were used. Synthesis was performed in the same manner.

・・・（３０−１３） As a result of measuring the molecular weight of the obtained polymer by GPC, Mn was 29,000 and Mw was 63,000. The ion exchange capacity was 2.27 meq / g. The obtained polymer was a polymer represented by the following general formula (30-13).

... (30-13)

[Production of proton conducting membrane]
The polymer obtained in this example was dissolved in N-methyl-2-pyrrolidone at a concentration of 14 to 16%, cast on a glass plate, and dried to obtain a film having a thickness of 40 μm.

[Production of membrane-electrode assembly]
A membrane-electrode assembly was obtained in the same manner as in Example 1 except that the proton conductive membrane obtained in this example was used.

・・・（４０−１） <Example 5>
[Synthesis of sulfonic acid unit]
A monomer was obtained in the same manner as in Example 1 except that 2-hydroxypyridine was changed to imidazole. It was confirmed that the obtained compound was a monomer represented by the following formula (40-1).

... (40-1)

[Synthesis of sulfonated polymer]
Polymer synthesis was performed using 59.53 g (96.4 mmol) of the above (40-1), 40.32 g (3.6 mmol) of the above (30-6), and 50.23 g (578 mmol) of lithium bromide. Synthesis was carried out in the same manner as in Example 1.

・・・（４０−２） As a result of measuring the molecular weight of the obtained polymer by GPC, Mn was 32,000 and Mw was 54,000. The ion exchange capacity was 2.26 meq / g. The obtained polymer was a polymer represented by the following general formula (40-2).

... (40-2)

[Production of proton conducting membrane]
The polymer obtained in this example was dissolved in N-methyl-2-pyrrolidone at a concentration of 14 to 16%, cast on a glass plate, and dried to obtain a film having a thickness of 40 μm.

[Production of membrane-electrode assembly]
A membrane-electrode assembly was obtained in the same manner as in Example 1 except that the proton conductive membrane obtained in this example was used.

<Example 6>
[Synthesis of sulfonated polymer]
Example 1 except that 58.48 g (94.7 mmol) of the above (40-1), 39.75 g (5.3 mmol) of the above (30-8), and 49.35 g (568 mmol) of lithium bromide were used. Synthesis was performed in the same manner.

・・・（４０−３） As a result of measuring the molecular weight of the obtained polymer by GPC, Mn was 40,000 and Mw was 73,000. The ion exchange capacity was 2.27 meq / g. The obtained polymer was a polymer represented by the following general formula (40-3).

... (40-3)

[Production of proton conducting membrane]
The polymer obtained in this example was dissolved in N-methyl-2-pyrrolidone at a concentration of 14 to 16%, cast on a glass plate, and dried to obtain a film having a thickness of 40 μm.

[Production of membrane-electrode assembly]
A membrane-electrode assembly was obtained in the same manner as in Example 1 except that the proton conductive membrane obtained in this example was used.

<Example 7>
[Synthesis of sulfonated polymer]
Example 1 except that 57.68 g (93.4 mmol) of the above (40-3), 39.62 g (6.6 mmol) of the above (30-10), and 48.67 g (560 mmol) of lithium bromide were used. Synthesis was performed in the same manner.

・・・（４０−４） As a result of measuring the molecular weight of the obtained polymer by GPC, Mn was 45,000 and Mw was 93,000. The ion exchange capacity was 2.27 meq / g. The obtained polymer was a polymer represented by the following general formula (40-4).

... (40-4)

[Production of proton conducting membrane]
The polymer obtained in this example was dissolved in N-methyl-2-pyrrolidone at a concentration of 14 to 16%, cast on a glass plate, and dried to obtain a film having a thickness of 40 μm.

[Production of membrane-electrode assembly]
A membrane-electrode assembly was obtained in the same manner as in Example 1 except that the proton conductive membrane obtained in this example was used.

<Example 8>
[Synthesis of sulfonated polymer]
Example 1 except that 55.83 g (90.4 mmol) of the above (40-1), 38.40 g (9.6 mmol) of the above (30-12), and 47.11 g (542 mmol) of lithium bromide were used. Synthesis was performed in the same manner.

・・・（４０−５） As a result of measuring the molecular weight of the obtained polymer by GPC, Mn was 32,000 and Mw was 60,000. The ion exchange capacity was 2.27 meq / g. The obtained polymer was a polymer represented by the following general formula (40-5).

... (40-5)

[Production of proton conducting membrane]
The polymer obtained in this example was dissolved in N-methyl-2-pyrrolidone at a concentration of 14 to 16%, cast on a glass plate, and dried to obtain a film having a thickness of 40 μm.

[Production of membrane-electrode assembly]
A membrane-electrode assembly was obtained in the same manner as in Example 1 except that the proton conductive membrane obtained in this example was used.

・・・（５０−１）

・・・（５０−２） <Example 9>
[Synthesis of sulfonic acid unit]
A compound represented by the following general formula (50-1) was obtained by reacting dichlorobenzene and nicotinic acid chloride in nitrobenzene in the presence of aluminum chloride. Sulfonation with fuming sulfuric acid, chlorosulfonation with phosphoryl chloride, and esterification with neopentyl alcohol were carried out in the same manner as in Example 1 to obtain a compound represented by the following general formula (50-2).

... (50-1)

... (50-2)

[Synthesis of sulfonated polymer]
Polymer synthesis was performed except that 39.69 g (98.7 mmol) of the above (50-2), 15.12 g (1.4 mmol) of the above (30-6), and 25.70 g (296 mmol) of lithium bromide were used. Synthesis was carried out in the same manner as in Example 1.

・・・（５０−３） As a result of measuring the molecular weight of the obtained polymer by GPC, Mn was 34,000 and Mw was 67,000. The ion exchange capacity was 2.26 meq / g. The obtained polymer was a polymer represented by the following general formula (50-3).

... (50-3)

[Production of proton conducting membrane]
The polymer obtained in this example was dissolved in N-methyl-2-pyrrolidone at a concentration of 14 to 16%, cast on a glass plate, and dried to obtain a film having a thickness of 40 μm.

[Production of membrane-electrode assembly]
A membrane-electrode assembly was obtained in the same manner as in Example 1 except that the proton conductive membrane obtained in this example was used.

<Example 10>
[Synthesis of sulfonated polymer]
Polymer synthesis was performed except that 39.42 g (98.0 mmol) of the above (50-2), 15.0 g (2.0 mmol) of the above (30-8), and 25.53 g (294 mmol) of lithium bromide were used. Synthesis was carried out in the same manner as in Example 1.

・・・（５０−４） As a result of measuring the molecular weight of the obtained polymer by GPC, Mn was 33,000 and Mw was 70,000. The ion exchange capacity was 2.25 meq / g. The obtained polymer was a polymer represented by the following general formula (50-4).

... (50-4)

[Production of proton conducting membrane]
The polymer obtained in this example was dissolved in N-methyl-2-pyrrolidone at a concentration of 14 to 16%, cast on a glass plate, and dried to obtain a film having a thickness of 40 μm.

[Production of membrane-electrode assembly]
A membrane-electrode assembly was obtained in the same manner as in Example 1 except that the proton conductive membrane obtained in this example was used.

<Example 11>
[Synthesis of sulfonated polymer]
Polymer synthesis was performed except that 39.22 g (97.5 mmol) of the above (50-2), 15.00 g (2.5 mmol) of the above (30-10), and 25.40 g (293 mmol) of lithium bromide were used. Synthesis was carried out in the same manner as in Example 1.

・・・（５０−５） As a result of measuring the molecular weight of the obtained polymer by GPC, Mn was 42,000 and Mw was 81,000. The ion exchange capacity was 2.29 meq / g. The obtained polymer was a polymer represented by the following general formula (50-5).

... (50-5)

[Production of proton conducting membrane]
The polymer obtained in this example was dissolved in N-methyl-2-pyrrolidone at a concentration of 14 to 16%, cast on a glass plate, and dried to obtain a film having a thickness of 40 μm.

[Production of membrane-electrode assembly]
A membrane-electrode assembly was obtained in the same manner as in Example 1 except that the proton conductive membrane obtained in this example was used.

<Example 12>
[Synthesis of sulfonated polymer]
Polymer synthesis was performed except that 38.74 g (96.3 mmol) of the above (50-2), 14.80 g (3.7 mmol) of the above (30-12), and 25.09 g (289 mmol) of lithium bromide were used. Synthesis was carried out in the same manner as in Example 1.

・・・（５０−６） As a result of measuring the molecular weight of the obtained polymer by GPC, Mn was 32,000 and Mw was 66,000. The ion exchange capacity was 2.26 meq / g. The obtained polymer was a polymer represented by the following general formula (50-6).

... (50-6)

[Production of proton conducting membrane]
The polymer obtained in this example was dissolved in N-methyl-2-pyrrolidone at a concentration of 14 to 16%, cast on a glass plate, and dried to obtain a film having a thickness of 40 μm.

[Production of membrane-electrode assembly]
A membrane-electrode assembly was obtained in the same manner as in Example 1 except that the proton conductive membrane obtained in this example was used.

・・・（６０−１） <Comparative Example 1>
304 mL of dried DMAc was compounded by 62.1 g (96.5 mmol) of the compound represented by the following general formula (60-1) and 39.20 g (3.5 mmol) of the above (30-6), bis (triphenylphosphine) nickel dichloride. Example 1 except that the reaction was carried out under the conditions of 3.27 g (5.0 mmol), triphenylphosphine 10.49 g (40 mmol), sodium iodide 0.45 g (3.0 mmol), and zinc 15.69 g (240 mmol). The synthesis was performed in the same manner as described above.

... (60-1)

・・・（６０−２） As a result of measuring the molecular weight of the obtained polymer by GPC, Mn was 57,000 and Mw was 165,000. The ion exchange capacity was 2.26 meq / g. The obtained polymer was a polymer represented by the following general formula (60-2).

... (60-2)

[Production of proton conducting membrane]
The polymer obtained in this comparative example was dissolved in N-methyl-2-pyrrolidone at a concentration of 14 to 16%, cast on a glass plate, and then dried to obtain a film having a thickness of 40 μm.

[Production of membrane-electrode assembly]
A membrane-electrode assembly was obtained in the same manner as in Example 1 except that the proton conductive membrane obtained in this comparative example was used.

[Evaluation]
Table 1 shows the characteristics of the sulfonated polymers obtained in Examples 1 to 12 and Comparative Example 1, respectively, and the evaluation results of the membrane-electrode structures produced using them.

  As shown in Table 1, according to this example, by using a sulfonated polyarylene obtained from a monomer having a nitrogen-containing heterocycle containing a sulfonic acid group in the side chain as a proton conducting membrane, It was confirmed that a membrane-electrode structure excellent in power generation durability at high temperatures was obtained.

Claims (6)

In a membrane-electrode structure for a polymer electrolyte fuel cell in which an anode electrode is provided on one side of a proton conducting membrane and a cathode electrode is provided on the other side,
The proton conductive membrane has a repeating unit represented by the following general formula (2): A membrane-electrode structure for a polymer electrolyte fuel cell, wherein

... (2)
Wherein (2), Y _{is, -CO -, - SO 2 -} , - SO -, - CONH -, - COO -, - (CF 2) l - (l is an integer of 1 to 10) And at least one structure selected from the group consisting of —C (CF ₃ ) ₂ —. W is a direct bond, —CO—, —SO ₂ —, —SO—, —CONH—, —COO—, — (CF ₂ ) ₁ — (l is an integer of 1 to 10), —C ( CF ₃ ) ₂ —, —O—, and —S— represent at least one structure selected from the group consisting of —S—. Z is a direct bond, or — (CH ₂ ) ₁ — (l is an integer of 1 to 10), —C (CH ₃ ) ₂ —, —O—, —S—, —CO—, and 1 shows at least one structure selected from the group consisting of —SO ₂ —. R ²⁰ represents at least one substituent represented by —SO ₃ H, —O (CH ₂ ) _h SO ₃ H, or —O (CF ₂ ) _h SO ₃ H (h is an integer of 1 to 12). The nitrogen-containing heterocycle which has one piece is shown. p shows the integer of 0-10, q shows the integer of 0-10, r shows the integer of 1-5, k shows the integer of 0-4. ]   The nitrogen-containing heterocyclic ring is pyrrole, thiazole, isothiazole, oxazole, isoxazole, imidazole, imidazoline, imidazolidine, pyrazole, 1,3,5-triazine, pyridine, pyrimidine, pyridazine, pyrazine, indole, quinoline, isoquinoline, Brine, tetrazole, tetrazine, triazole, carbazole, acridine, quinoxaline, quinazoline, indolizine, isoindole, 3H-indole, 2H-pyrrole, 1H-indazole, purine, phthalazine, naphthyridine, cinnoline, pteridine, carboline, phenanthridine, Perimidine, phenanthroline, phenazine, phenalsazine, phenothiazine, furazane, phenoxazine, pyrrolidine, pyrroline, pyrazoline, pyrazolid 2. A group derived from at least one compound selected from the group consisting of nitrogen-containing heterocycles consisting of, piperidine, piperazine, indoline, isoindoline, quinuclidine, and derivatives thereof. A membrane-electrode structure for a polymer electrolyte fuel cell. The membrane-electrode structure for a polymer electrolyte fuel cell according to claim 1 or 2, further comprising a repeating unit represented by the following general formula (3).

... (3)
Wherein (3), A and C are each independently a direct _{bond, -CO -, - SO 2 -} , - SO -, - CONH -, - COO -, - (CF 2) l - (l is , an integer of 1 to _{10), - C (CF 3)} 2 -, - (CH 2) l - (l is an integer of 1 to _{10), - C (CR '2} ) 2 - (R 'Represents a hydrocarbon group or a cyclic hydrocarbon group), at least one structure selected from the group consisting of —O— and —S—. B independently represents an oxygen atom or a sulfur atom. R ^{1 to} R ¹⁶ may be the same or different from each other, and are a hydrogen atom, a fluorine atom, an alkyl group, a halogenated alkyl group partially or wholly halogenated, an allyl group, an aryl group, a nitro group, and a nitrile. At least one atom or group selected from the group consisting of groups is shown. s and t each independently represent an integer of 0 to 4, and u represents an integer of 0 or more. ] Y represents —CO— or —SO ₂ —, and W and Z are each independently selected from the group consisting of a direct bond, —CO—, —SO ₂ —, —O—, and —S—. The solid polymer according to any one of claims 1 to 3, wherein the solid polymer represents at least one selected structure, wherein p and q are integers of 0 to 2, and r is an integer of 1 to 2. Type fuel cell membrane-electrode structure. R ²⁰ represents at least a substituent represented by —SO ₃ H, —O (CH ₂ ) _h SO ₃ H, or —O (CF ₂ ) _h SO ₃ H (h is an integer of 1 to 12). 5. The polymer electrolyte fuel according to claim 1, wherein the solid polymer fuel is a group derived from at least one compound selected from the group consisting of one pyridine, imidazole, triazole, and derivatives thereof. Battery membrane-electrode structure.   6. The membrane-electrode structure for a polymer electrolyte fuel cell according to claim 1, wherein the proton exchange membrane has an ion exchange capacity of 0.5 meq / g to 3 meq / g.