JP2005320523A - Polyarylene polymer and its use - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyarylene polyelectrolyte that exhibits superior performance in many characteristics such as film-forming properties, chemical stability, film mechanical strength, water resistance and proton conductivity, in particular in proton conductivity, etc., as a proton conductive film for a solid polymer fuel cell, and exhibits high power generation characteristics. <P>SOLUTION: This polyarylene polymer is characterized by having a repeating structure represented by general formula (1), wherein X represents any one of a direct bonding, -O-, -S-, -SO-, -SO<SB>2</SB>- and -CO-, Y represents each a direct bonding, a divalent or a trivalent aromatic group, R<SP>1</SP>and R<SP>2</SP>represent each independently a hydrogen atom or a fluorine atom, R<SP>3</SP>represents each independently a sulfonic acid group, a 1-10C alkyl group or a 6-18C aryl group that may be substituted, i represents a number of 0-3, k represents a number of 1-12, and l represents one when Y is the direct bonding or the divalent aromatic group and represents two when Y is the trivalent aromatic group. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polyarylene polymer, and more particularly to a polyarylene polymer suitably used as a polymer electrolyte, particularly a fuel cell, and its use.

  Polymers having proton conductivity, that is, polymer electrolytes, are used as diaphragms for electrochemical devices such as primary batteries, secondary batteries, and solid polymer fuel cells. For example, Nafion (registered trademark of DuPont) and other polymers that contain perfluoroalkylsulfonic acid as a super strong acid in the side chain and an aliphatic polymer whose main chain is perfluoroalkane as an active ingredient Conventionally, electrolytes have been mainly used because of their excellent power generation characteristics when used as membrane materials for fuel cells and ion exchange components. However, it has been pointed out that this type of material is very expensive, has low heat resistance, has low film strength, and is not practical without some reinforcement.

Under these circumstances, development of inexpensive and excellent polymer electrolytes that can replace the above polymer electrolytes has recently been activated, and polyarylene polymer electrolytes having polyphenylene in the main chain structure have been studied.
For example, as a repeating structure, a polyarylene polymer electrolyte having a phenylene unit having a substituent, and the substituent is an aromatic group having a sulfonic acid group at the terminal, such as a sulfophenoxybenzoyl group ( Patent Document 1), as a repeating unit, a polyarylene polymer electrolyte (Patent Document 2) having a phenylene unit having a substituent similar to the above and a benzophenone unit has been proposed.

US Pat. No. 5,403,675 JP 2001-342241 A

  However, when the polyarylene polymer electrolyte as described above is used for a polymer electrolyte fuel cell, the temperature dependency of the power generation characteristics, the humidity dependency, the physical properties such as the water resistance and the solvent resistance, and the tensile strength in the membrane shape. Further improvements were expected from problems such as characteristics, flexibility, mechanical properties such as elasticity, and processability of the membrane-electrode assembly manufacturing process, which are not sufficiently satisfactory.

  As a result of intensive investigations to find a polymer exhibiting superior performance as a polymer electrolyte for fuel cells and the like, the present inventors have obtained a terminal as a substituent in a phenylene unit having a substituent as a repeating structure. A polyarylene polymer having an aliphatic group having a sulfonic acid group at its end instead of an aromatic group having a sulfonic acid group is used as a polymer electrolyte, particularly a proton conducting membrane of a solid polymer fuel cell. As film forming properties, chemical stability such as oxidation resistance, radical resistance and hydrolysis resistance, mechanical strength of the film, water resistance, and various properties such as proton conductivity and power generation characteristics, especially proton conductivity As a result, the present invention was completed.

That is, the present invention provides [1] the following general formula (1)

(In the formula, X represents a direct bond, —O—, —S—, —SO—, —SO ₂ — or —CO—, and Y represents a direct bond, a divalent or trivalent aromatic group. R ¹ and R ² each independently represent a hydrogen atom or a fluorine atom, and R ³ each independently represent a sulfonic acid group, an alkyl group having 1 to 10 carbon atoms or a carbon number of 6 to 18 Represents an optionally substituted aryl group, i represents a number from 0 to 3, k represents a number from 1 to 12, l represents 1 when Y is a direct bond or divalent, and Y represents In the case of a trivalent aromatic group, it represents 2.)
It provides a polyarylene polymer characterized by having a repeating structure represented by the following formula.
[2] The polymer according to [1], wherein 90% or more of the repeating structure represented by the general formula (1) is p-linked, that is, bonded at the para position. Is to provide.

In addition, the present invention provides [3] and the following general formulas (2) and (3)

(In the formula, Ar ¹ and Ar ² each independently represent a divalent aromatic group, where the divalent aromatic group is an alkyl group having 1 to 10 carbon atoms and 6 to 18 carbon atoms. It may be substituted with an aryl group or a sulfonic acid group, Z represents any of —O—, —SO ₂ —, and —CO—, m represents a number of 1 or more, and n represents a number of 0 or more. R ⁴ represents a sulfonic acid group, an alkyl group having 1 to 10 carbon atoms, an optionally substituted aryl group having 6 to 18 carbon atoms, or an acyl group having 2 to 20 carbon atoms, independently of each other. And p represents a number of 0 to 4.) The polymer according to [1] or [2] is provided having at least one repeating structure represented by the following formula:

Further, the present invention is [4] above, wherein 90% or more of the repeating structure represented by the general formula (3) in the main chain is p-linked, that is, bonded at the para position. 3],
[5] The polymer of [1] to [4] above, wherein Y is a direct bond,
[6] The polymer according to any one of [1] to [5], wherein i is 0,
[7] The polymer according to [1] to [6], wherein the ion exchange capacity is 0.5 eq / g to 4 meq / g,
[8] The polymer of [1] to [7] above, which is a random copolymer or a block copolymer,

[9] A polymer electrolyte comprising the polymer of [1] to [8] as an active ingredient,
[10] A polymer electrolyte membrane comprising the polymer electrolyte of [9] above,
[11] A catalyst composition comprising the polymer electrolyte of [9] above,
[12] A polymer electrolyte fuel comprising at least one selected from the polymer electrolyte of [9], the polymer electrolyte membrane of [10], and the catalyst composition of [11] A battery or the like is provided.

  The polyarylene polymer of the present invention is used as a polymer electrolyte, particularly as a proton conductive membrane of a solid polymer fuel cell, as a film stability, chemical stability such as oxidation resistance, radical resistance and hydrolysis resistance, It exhibits excellent performance in various properties such as mechanical strength, water resistance, and proton conductivity of the membrane, particularly in properties such as proton conductivity. In addition, when used as a proton conductive membrane of a polymer electrolyte fuel cell, it exhibits high power generation characteristics, so that the polyarylene polymer of the present invention is industrially advantageous as a polymer electrolyte.

Hereinafter, the present invention will be described in detail.
The polyarylene polymer of the present invention is characterized in that the form of the free acid has a repeating structure represented by the general formula (1).
Here, —X— in the formula (1) represents any of a direct bond, —O—, —S—, —SO—, —SO ₂ —, and —CO—, and among them, a direct bond, —O— , —SO ₂ — and —CO— are preferable.
Y represents a direct bond or a divalent or trivalent aromatic group, and the total number of carbon atoms is usually about 6 to 18, and is derived from an aromatic ring that may have a substituent. Examples of the aromatic ring which may have such a substituent include benzene, naphthalene, and those in which these groups are substituted with a fluorine atom, methoxy, ethoxy, isopropyloxy, biphenylyl, phenoxy, naphthyloxy group or the like. Needless to say, when the number 1 of the sulfonic acid groups is 1, it is divalent, and when 1 is 2, it becomes a trivalent aromatic group. Preferable examples include the following groups when including a sulfonic acid group, and a direct bond is particularly preferable.
(In the formula, l represents the same meaning as described above.)
R ¹ and R ² each independently represents a hydrogen atom or a fluorine atom, and preferably both are hydrogen or a fluorine atom.

R ³ represents a substituent on phenylene in the polymer main chain, and may be a sulfonic acid group, an alkyl group having about 1 to 10 carbon atoms, or a substituted group having about 6 to 18 carbon atoms. Represents an aryl group.
Examples of the alkyl group having about 1 to 10 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, n-pentyl, 2,2-dimethylpropyl, cyclopentyl, n- Hexyl, cyclohexyl, 2-methylpentyl, 2-ethylhexyl, nonyl, etc. may be mentioned. Examples of the aryl group having about 6 to 18 carbon atoms which may be substituted include phenyl, naphthyl and fluorine in these groups. Examples include those substituted with an atom, methoxy, ethoxy, isopropyloxy, biphenylyl, phenoxy, naphthyloxy, sulfonic acid group and the like.

i is the number of substituted R ³ and represents a number of 0 to 3, and i is preferably 0, or R ³ is preferably methyl or ethyl. k represents a number of 1 to 12, and preferably 2 to 6. l represents 1 when Y is a direct bond or divalent, and 2 when Y is a trivalent aromatic group.
The phenylene constituting the main chain may be o-, m-, p-, or a mixture of two or more of these, but 90% or more of the repeating structure is preferably p-linked. That is, phenylene in the polymer main chain is bonded to other repeating units at the ortho position, meta position, and para position and does not have to be all at the same bonding position, but 90% or more of the repeating units are adjacent to both repeating units. Are preferably bonded at the para position.

Typical examples of the repeating structure represented by the general formula (1) include the following.

  The polyarylene polymer of the present invention has the repeating unit represented by the general formula (1) as described above. The polyarylene polymer of the present invention includes those in which some or all of the sulfonic acid groups are in the form of a salt. Examples of such salt forms include alkali metal salts or alkaline earth metal salts such as lithium salts, sodium salts, potassium salts, and calcium salts. When used as a material for a polymer electrolyte fuel cell, it is preferable that substantially all sulfonic acid groups in the polyarylene polymer are in the form of a free acid.

The polyarylene polymer of the present invention may have a different repeating structure in addition to the repeating structure represented by the general formula (1) as described above.
For example, it is preferable to further have a repeating structural unit represented by the general formula (2), the general formula (3) or the like.
Here, Ar ¹ and Ar ² in the general formula (2) each independently represent a divalent aromatic group, and the divalent aromatic group includes two divalent groups derived from an aromatic ring, The aromatic ring is preferably a divalent group connected directly or via a connecting member.
Examples of such a divalent aromatic group include the following divalent groups.

The divalent groups Ar ¹ and Ar ² containing these have an aromatic ring of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, isobutyl, n-pentyl, 2,2 -An alkyl group having about 1 to 10 carbon atoms such as dimethylpropyl, cyclopentyl, n-hexyl, cyclohexyl, 2-methylpentyl, 2-ethylhexyl, nonyl, decyl, phenyl, naphthyl, fluorine atom in these groups, Methyl, ethoxy, isopropyloxy, biphenylyl, phenoxy, naphthyloxy and the like may be substituted with an aryl group having a total carbon number of about 6-18, a sulfonic acid group, etc., but unsubstituted or sulfonic acid Substitution is preferred.

Z represents any of —O—, —SO ₂ —, and —CO—, and a plurality of Z may be different from each other. m represents a number of 1 or more, n represents a number of 0 or more, and m + n is preferably a number of 1 to 1000.
Typical examples of the repeating structure represented by the general formula (2) include the following. m and n represent the same meaning as described above.

R ⁴ in the general formula (3) represents a substituent on the benzene ring, and independently of each other, a sulfonic acid group, an alkyl group having about 1 to 10 carbon atoms, and an aryl having about 6 to 18 carbon atoms. The group also represents an acyl group having about 2 to 20 carbon atoms.
Here, examples of the alkyl group having about 1 to 10 carbon atoms and the aryl group having about 6 to 18 carbon atoms include the same alkyl groups and aryl groups as described above. Examples of the acyl group having about 2 to 20 carbon atoms include acetyl, propionyl, butyryl, isobutyryl, benzoyl, 1-naphthoyl, 2-naphthoyl, fluorine atom, methoxy, ethoxy, isopropyloxy, biphenylyl, Examples include acyl groups substituted with phenoxy, naphthyloxy, sulfonic acid groups, and the like.
Of these, R ⁴ is preferably benzoyl or phenoxybenzoyl. p is the number of R ⁴ substituted, and represents a number of 0 to 4. p is preferably 0.
Further, phenylene in the general formula (3) is bonded at the ortho position, the meta position, and the para position and does not need to be all at the same bonding position, but 90% or more of the repeating units are bonded to the adjacent repeating units at the para position. It is preferable.

Typical examples of the repeating structure represented by the general formula (3) include the following.

The polyarylene polymer of the present invention is represented by the general formula (2) and / or the general formula (3) as described above in addition to the repeating structure represented by the general formula (1) as described above. The composition ratio may be such that the introduction ratio of acid groups as the polyarylene polymer is 0.5 meq / g to 4 meq / g in terms of ion exchange capacity. A preferable composition ratio is preferable. When the ion exchange capacity is less than 0.5, proton conductivity is lowered, and the function as a polymer electrolyte for a fuel cell may be insufficient. The lower limit of the ion exchange capacity is preferably 1.0 or more, and particularly preferably 1.5 or more.
On the other hand, if the ion exchange capacity exceeds 4, the water resistance may decrease, which is not preferable. The upper limit of the ion exchange capacity is preferably 3.8 or less, and particularly preferably 3.5 or less.

Further, for example, when it has a repeating structural unit represented by the general formula (2) and / or the general formula (3) as described above, it is a random copolymer having a random coupling mode, that is, a copolymerization mode. Alternatively, it may be a block copolymer repeated in a block manner, or a combination thereof.
When it is a random copolymer, the case where (m + n) is 1 or 2 is suitable as the general formula (2). Moreover, when it is a block copolymer, although it has a block in which General formula (1) and General formula (2) and / or (3) are each independently repeated, As the frequency | count of repetition, General formula (1) In the case, 10 to 100 times are preferable, in the case of the general formula (2), (m + n) is preferably 10 to 100, and in the case of the general formula (3), 10 to 200 times are preferable.

  The molecular weight of the polyarylene polymer of the present invention is preferably from 5,000 to 1,000,000, particularly preferably from 15,000 to 1,000, expressed as a number average molecular weight in terms of polystyrene.

As typical examples in the case of having a repeating structural unit represented by the general formulas (2), (3), etc., the following can be exemplified. Here, the number of repetitions of each repeating structure is omitted, but the number of repetitions satisfying the ion exchange capacity, composition ratio, block length, molecular weight and the like as described above is preferable.

Next, the method for producing the polyarylene polymer of the present invention will be described.
The polyarylene polymer of the present invention is represented by, for example, a monomer represented by the following formula (4) in the coexistence of a zero-valent transition metal complex, and the following formulas (5) and (6) used as necessary. Monomers can be produced by polymerizing by a condensation reaction.

(In the formula, Ar ¹ , Ar ² , R ^{1 to} R ⁴ , X, Y, i, k, m, n, l, and p have the same meaning as described above. Q is a group that is eliminated during the condensation reaction. And the plurality of Qs may be of different types.)

  Here, Q represents a group leaving during the condensation reaction. Specific examples thereof include halogeno groups such as chloro, bromo and iodo, p-toluenesulfonyloxy group, methanesulfonyloxy group, trifluoromethane, and the like. And sulfonic acid ester groups such as a sulfonyloxy group.

Polymerization by condensation reaction is carried out in the presence of a zero-valent transition metal complex. Examples of such a zero-valent transition metal complex include a zero-valent nickel complex and a zero-valent palladium complex. Of these, a zerovalent nickel complex is preferably used.
As the zero-valent transition metal complex, a commercially available product or a separately synthesized one may be used for the polymerization reaction system, or may be generated from the transition metal compound by the action of a reducing agent in the polymerization reaction system. In the latter case, for example, a method in which zinc, magnesium or the like is allowed to act on the transition metal compound as a reducing agent.
In any case, it is preferable to add a ligand described later from the viewpoint of improving the yield.

Here, examples of the zero-valent palladium complex include palladium (0) tetrakis (triphenylphosphine). Examples of the zero-valent nickel complex include nickel (0) bis (cyclooctadiene), nickel (0) (ethylene) bis (triphenylphosphine), nickel (0) tetrakis (triphenylphosphine), and the like. Of these, nickel (0) bis (cyclooctadiene) is preferably used.
In addition, when a reducing agent is allowed to act on a transition metal compound to generate a zero-valent transition metal complex, the transition metal compound used is usually a divalent transition metal compound, but a zero-valent one should also be used. You can also. Of these, divalent nickel compounds and divalent palladium compounds are preferred. Examples of divalent nickel compounds include nickel chloride, nickel bromide, nickel iodide, nickel acetate, nickel acetylacetonate, nickel chloride bis (triphenylphosphine), nickel bromide bis (triphenylphosphine), nickel iodide bis ( Triphenylphosphine) and the like, and examples of the divalent palladium compound include palladium chloride, palladium bromide, palladium iodide, palladium acetate and the like.

Examples of the reducing agent include metals such as zinc and magnesium and alloys thereof such as copper, sodium hydride, hydrazine and derivatives thereof, and lithium aluminum hydride. If necessary, ammonium iodide, trimethylammonium iodide, triethylammonium iodide, lithium iodide, sodium iodide, potassium iodide and the like can be used in combination.
When the reducing agent is not used, the amount of the zero-valent transition metal complex used is the total amount of the monomer represented by the formula (4) and the monomers represented by the formulas (5) and (6) used as necessary. Usually, it is 0.1 to 5 mole times. If the amount used is too small, the molecular weight tends to be small, so it is preferably 1.5 mole times or more, more preferably 1.8 mole times or more, and even more preferably 2.1 mole times or more. The upper limit of the amount used is preferably 5.0 moles or less because the amount of use is too large and post-treatment tends to become complicated.
Moreover, when using a reducing agent, the usage-amount of a transition metal compound is with respect to the monomer shown by Formula (4), and the total amount of the monomer shown by Formula (5) and Formula (6) used as needed. And 0.01 to 1 mole times. If the amount used is too small, the molecular weight tends to be small, so the amount is preferably 0.03 mol times or more. The upper limit of the amount used is preferably 1.0 mole or less because the amount of use is too large and post-treatment tends to be complicated.

  The amount of the reducing agent used is usually 0.5 to 10 mol based on the monomer represented by formula (4) and the total amount of monomers represented by formula (5) and formula (6) used as necessary. Is double. If the amount used is too small, the molecular weight tends to be small, so the amount is preferably 1.0 mole or more. The upper limit of the amount used is desirably 10 moles or less because if the amount used is too large, post-treatment tends to become complicated.

Examples of the ligand include 2,2′-bipyridyl, 1,10-phenanthroline, methylenebisoxazoline, N, N, N′N′-tetramethylethylenediamine, triphenylphosphine, tolylphosphine, tributylphosphine, Examples include triphenoxyphosphine, 1,2-bisdiphenylphosphinoethane, 1,3-bisdiphenylphosphinopropane, and triphenylphosphine in terms of versatility, low cost, high reactivity, and high yield. '-Bipyridyl is preferred. In particular, 2,2′-bipyridyl is preferably used because the yield of the polymer is improved when combined with bis (1,5-cyclooctadiene) nickel (0).
Moreover, when making a ligand coexist, it is about 0.2-10 mol times normally based on a metal atom basis with respect to a zerovalent transition metal complex, Preferably it is used about 1-5 mol times.

The condensation reaction is usually carried out in the presence of a solvent. Examples of such solvents include aromatic hydrocarbon solvents such as benzene, toluene, xylene, n-butylbenzene, mesitylene, and naphthalene: diisopropyl ether, tetrahydrofuran, 1,4-dioxane, diphenyl ether, dibutyl ether, tert-butyl methyl ether. , Ether solvents such as dimethoxyethane: N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), hexamethylphosphoric triamide, dimethyl sulfoxide ( Aprotic polar solvents substituted for amide solvents such as DMSO): aliphatic hydrocarbon solvents such as tetralin and decalin: ester solvents such as ethyl acetate, butyl acetate and methyl benzoate: chloroform, dichloro And halogenated alkyl solvents Tan, and the like.
In order to increase the molecular weight of the polymer to be generated, it is desirable that the polymer is sufficiently dissolved. Therefore, tetrahydrofuran, 1,4-dioxane, DMF, DMAc, DMSO, NMP, which are good solvents for the polymer, are used. , Toluene and the like are preferable. These may be used in combination of two or more. Among these, DMF, DMAc, DMSO, NMP, and a mixture of two or more of these are preferably used.

The solvent is usually used in an amount of 5 to 500 times by weight, preferably about 20 to 100 times the monomer.
The condensation temperature is usually in the range of 0 to 250 ° C., preferably about 10 to 100 ° C., and the condensation time is usually about 0.5 to 24 hours. Among them, in order to further increase the molecular weight of the polymer to be produced, the zero-valent transition metal complex, the monomer represented by the formula (4), and the formulas (5) and (6) used as necessary are used. The monomer is preferably allowed to act at a temperature of 45 ° C. or higher. The preferred working temperature is usually 45 ° C to 200 ° C, particularly preferably about 50 ° C to 100 ° C.
In addition, a method in which a zero-valent transition metal complex, a monomer represented by the formula (4), and a monomer represented by the formula (5) or the formula (6) used as required is a method of adding one to the other Alternatively, a method of adding both to the reaction vessel at the same time may be used. When adding, it may be added all at once, but it is preferable to add little by little in consideration of heat generation, and it is also preferable to add in the presence of a solvent.
After allowing the zero-valent transition metal complex to react with the monomer represented by the formula (4) and the monomer represented by the formula (5) or the formula (6) used as necessary, usually about 45 ° C to 200 ° C, Preferably, the temperature is kept at about 50 ° C to 100 ° C.

  A conventional method can be applied to take out the aromatic polymer produced by the condensation reaction from the reaction mixture. For example, the polymer can be precipitated by adding a poor solvent, and the target product can be taken out by filtration. Moreover, it can also refine | purify by normal purification methods, such as washing with water and reprecipitation using a good solvent and a poor solvent, as needed.

Thus, the polyarylene polymer of the present invention can be obtained and used as a polymer electrolyte. The obtained polymer can be identified and quantified by IR, NMR, liquid crossgraphy, etc., and the number of each repeating unit in the polymer chain can be determined by NMR. The molecular weight can be determined by gel permeation chromatography.
Moreover, the monomer shown by Formula (4) which is the raw material can be manufactured using a well-known method. For example, the method for introducing a sulfonic acid group via an alkyl group is not particularly limited, but a specific method is described in, for example, J.A. Amer. Chem. Soc. , 76, 5357 to 5360 (1954), a method of introducing a sulfonic acid group via an alkyl group into an aromatic ring using sultone. Further, for example, a method for introducing a sulfonic acid group via an alkoxy group is not particularly limited. As a specific method, for example, a compound having a hydroxy group is reacted with an alkali metal compound and / or an organic base compound. Then, after producing an alkali metal salt and / or an amine salt, it can be efficiently produced by reacting with a sulfonating agent such as propane sultone or sodium bromoethanesulfonate.

Next, the case where the polyarylene polymer of the present invention is used as a diaphragm of an electrochemical device such as a fuel cell will be described.
In this case, the polyarylene polymer of the present invention is usually used in the form of a film, but there is no particular limitation on the method of converting to a film, and for example, a method of forming a film from a solution state (solution casting method) is preferable. used.
Specifically, the polyarylene polymer is dissolved in an appropriate solvent, the solution is cast on a glass plate, and the solvent is removed to form a film. The solvent used for film formation is not particularly limited as long as it can dissolve the polyarylene polymer and can be removed thereafter. DMF, N, N-dimethylacetamide (DMAc), N-methyl-2 -Aprotic polar solvents such as pyrrolidone (NMP) and DMSO, or chlorinated solvents such as dichloromethane, chloroform, 1,2-dichloroethane, chlorobenzene and dichlorobenzene, alcohols such as methanol, ethanol and propanol, ethylene glycol monomethyl ether An alkylene glycol monoalkyl ether such as ethylene glycol monoethyl ether, propylene glycol monomethyl ether, or propylene glycol monoethyl ether is preferably used. These can be used singly, but two or more solvents can be mixed and used as necessary. Among these, DMSO, DMF, DMAc, NMP, and the like are preferable because of high polymer solubility.

  Although there is no restriction | limiting in particular in the thickness of a film, 10-300 micrometers is preferable and 20-100 micrometers is especially preferable. When the film is thinner than 10 μm, the practical strength may not be sufficient, and when the film is thicker than 300 μm, the film resistance tends to increase and the characteristics of the electrochemical device tend to deteriorate. The film thickness can be controlled by the concentration of the solution and the coating thickness on the substrate.

For the purpose of improving various physical properties of the film, plasticizers, stabilizers, mold release agents and the like used for ordinary polymers can be added to the block copolymer of the present invention. Also, other polymers can be combined with the copolymer of the present invention by a method such as co-casting in the same solvent.
In addition, in fuel cell applications, it is also known to add inorganic or organic fine particles as a water retention agent in order to facilitate water management. Any of these known methods can be used.
Further, for the purpose of improving the mechanical strength of the film, it can be crosslinked by irradiating with an electron beam or radiation. Furthermore, there are known methods of impregnating a porous film or sheet into a composite and reinforcing a film by mixing fibers or pulp, and any of these known methods can be used. The film thus obtained can be suitably used as a polymer electrolyte.

Next, the fuel cell of the present invention will be described.
The fuel cell of the present invention can be produced by joining a catalyst and a conductive material as a current collector to both surfaces of a polyarylene polymer film.
The catalyst is not particularly limited as long as it can activate the oxidation-reduction reaction with hydrogen or oxygen, and a known catalyst can be used, but platinum fine particles are preferably used. The fine particles of platinum are often used by being supported on particulate or fibrous carbon such as activated carbon or graphite.
A known material can be used for the conductive material as the current collector, but porous carbon woven fabric, carbon non-woven fabric, or carbon paper is preferable in order to efficiently transport the raw material gas to the catalyst.

For a method of bonding platinum fine particles or carbon carrying platinum fine particles to a porous carbon nonwoven fabric or carbon paper, and a method of bonding it to a polymer electrolyte film, see, for example, J. Org. Electrochem. Soc. : Known methods such as those described in Electrochemical Science and Technology, 1988, 135 (9), 2209 can be used.
The polyarylene polymer of the present invention can also be used as a proton conducting material that is a component of a catalyst composition constituting a catalyst layer of a solid polymer fuel cell.
The fuel cell of the present invention thus produced can be used in various forms using hydrogen gas, reformed hydrogen gas, methanol, or the like as fuel.
While the embodiments of the present invention have been described above, the embodiments of the present invention disclosed above are merely examples, and the scope of the present invention is not limited to these embodiments. The scope of the present invention is defined by the terms of the claims, and further includes meanings equivalent to the description of the claims and all modifications within the scope.

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.
The molecular weights described in the examples are number average molecular weight (Mn) and weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC) under the following conditions.
GPC measuring device HLC-8220 manufactured by TOSOH
Column Example 1-4: Connected with KD-80M + KD-803 manufactured by Shodex
Example 5: Two AT-80Ms manufactured by Shodex, connected column temperature 40 ° C
Mobile phase solvent DMAc (LiBr added to 10 mmol / dm ³ )
Solvent flow rate 0.5mL / min
The proton conductivity was measured by an alternating current method under the conditions of a temperature of 80 ° C. and a relative humidity of 90% using a membrane obtained by a solution cast method using the solvents described in each example. The ion exchange capacity (IEC) was determined by a titration method.

Preparation of Membrane / Electrode Assembly To 6 mL of Nafion solution (5 wt%, manufactured by Aldrich), 603 mg of platinum-supporting carbon (E-tec) supporting 30 wt% of platinum and 13.2 mL of ethanol were added, and the catalyst layer was stirred well. A solution was prepared. This catalyst layer solution was applied to a gas diffusion layer (carbon cloth) by screen printing so that the platinum carrying density was 0.6 mg / cm ² , and the solvent was removed to obtain a membrane electrode assembly.

Preparation of fuel cell A commercially available ElectroChem cell was used. A fuel cell having an effective membrane area of 5 cm ² was assembled by disposing a carbon separator in which gas passage grooves were cut on both outer sides of the membrane electrode assembly and an end plate and fastening them with bolts.

Evaluation of power generation performance of fuel cell The fuel cell was kept at 80 ° C., humidified hydrogen was supplied to the anode, and humidified air was supplied to the cathode so that the back pressure at the gas outlet of the cell was 0.1 MPaG. Humidification was performed by passing a gas through a bubbler. The water temperature of the hydrogen bubbler was 90 ° C., and the water temperature of the air bubbler was 80 ° C. The hydrogen gas flow rate was 300 mL / min, and the air gas flow rate was 1000 mL / min.

Synthesis example 1
(Synthesis of 3- (2,5-dichlorophenoxy) propanesulfonic acid sodium salt)
Under an argon atmosphere, DMAc 150 ml, toluene 75 ml, 2,5-dichlorophenol 24.15 g (148.2 mmol), sodium carbonate 47.10 g (444.4 mmol) were placed in a flask, and heated and stirred to azeotrope conditions of toluene and water. After dehydration below, toluene was distilled off. After allowing to cool to room temperature, 50.00 g (222.2 mmol) of sodium 3-bromopropanesulfonate was added, the temperature was raised to 100 ° C., and the mixture was stirred at the same temperature for 10 hours. After allowing to cool, the solid was removed by suction filtration, a large amount of chloroform was added to the obtained filtrate, and the precipitated white solid was separated by filtration. Further, 35.2 g (77% yield) of sodium 3- (2,5-dichlorophenoxy) propanesulfonate was obtained by a recrystallization method.

Example 1
Under an argon atmosphere, the flask was charged with 70 ml of DMSO, 2.50 g (8.14 mmol) of sodium 3- (2,5-dichlorophenoxy) propanesulfonate obtained in Synthesis Example 1, 5.11 g of 2,5-dichlorobenzophenone (20 .35 mmol) and 2,2′-bipyridyl (13.63 g, 87.30 mmol) were added and stirred, and the temperature was raised to 60 ° C. Next, 21.83 g (79.36 mmol) of nickel (0) bis (cyclooctadiene) was added thereto, the temperature was raised to 80 ° C., and the mixture was stirred at the same temperature for 9 hours. After allowing to cool, the reaction solution is poured into a large amount of 4N hydrochloric acid to precipitate a polymer, filtered, washed with water until the filtrate is neutral, and then dried under reduced pressure to obtain the desired polyphenylene sulfonic acids 5 .38 g was obtained.
Mn = 20000, Mw = 300000
IEC = 1.45 meq / g (calculated as a / (a + b) = 0.28)
Proton conductivity 1.75 × 10 ⁻² S / cm (DMSO was used for casting)

Example 2
Under an argon atmosphere, 85 ml of DMSO, 5.00 g (16.28 mmol) of sodium 3- (2,5-dichlorophenoxy) propanesulfonate obtained in Synthesis Example 1 and the following polyethersulfone which is a terminal chloro type were placed in a flask.
(Sumitomo Chemical Industries Sumika Excel PES5200P, Mn = 5.44 × 10 ⁴ , Mw = 1.23 × 10 ⁵ ) 2.03 g, 2,2′-bipyridyl 9.83 g (62.96 mmol) was added and stirred. The temperature was raised to 60 ° C. Next, 15.74 g (57.23 mmol) of nickel (0) bis (cyclooctadiene) was added thereto, the temperature was raised to 80 ° C., and the mixture was stirred at the same temperature for 20 hours. After allowing to cool, the polymer is precipitated by pouring the reaction solution into a large amount of 4N hydrochloric acid, filtered, washed with water until the filtrate becomes neutral, and then dried under reduced pressure to obtain the desired polyphenylene sulfonic acids. 32 g were obtained.
Mn = 18000, Mw = 400000
IEC = 2.32 meq / g (calculated as a / (a + ((n + 1) × b)) = 0.51)
Proton conductivity 2.04 × 10 ⁻¹ S / cm (DMSO was used for casting)
Fuel cell power generation performance evaluation results
Cell voltage 0.70 V when current density is 0.50 A / cm ²
Cell voltage 0.54 V when current density is 1.00 A / cm ²

Example 3
Under an argon atmosphere, the flask was charged with 70 ml of DMSO, 5.50 g (17.92 mmol) of sodium 3- (2,5-dichlorophenoxy) propanesulfonate obtained in Synthesis Example 1, and 0.50 g of 4,4′-dichlorobenzophenone ( 1.99 mmol) and 2,2′-bipyridyl (0.009 g, 64.61 mmol) were added and stirred, and the temperature was raised to 60 ° C. Next, 16.16 g (58.74 mmol) of nickel (0) bis (cyclooctadiene) was added thereto, the temperature was raised to 80 ° C., and the mixture was stirred at the same temperature for 6 hours. After cooling, the polymer is precipitated by pouring the reaction solution into a large amount of 4N hydrochloric acid, filtered, washed with water until the filtrate is neutral, washed with acetone, and then dried under reduced pressure. 4.22 g of polyphenylene sulfonic acids were obtained.
Mn = 30000, Mw = 5800000,
IEC = 3.95 meq / g (calculated as a / (a + b) = 0.82)
Proton conductivity 4.64 × 10 ⁻¹ S / cm (DMSO was used for casting)

Synthesis example 2
(Synthesis of 3- (2,5-dichlorophenoxy) ethanesulfonic acid sodium salt)
Under an argon atmosphere, DMAc 150 ml, toluene 75 ml, 2,5-dichlorophenol 11.84 g (72.6 mmol), sodium carbonate 23.10 g (217.9 mmol) were placed in a flask, heated and stirred, and azeotrope conditions of toluene and water After dehydration below, toluene was distilled off. After allowing to cool to room temperature, 23.00 g (109.0 mmol) of sodium 3-bromoethanesulfonate was added, the temperature was raised to 100 ° C., and the mixture was stirred at the same temperature for 10 hours. After allowing to cool, the solid was removed by suction filtration, a large amount of chloroform was added to the obtained filtrate, and the precipitated white solid was separated by filtration. Further, 14.3 g (67% yield) of sodium 3- (2,5-dichlorophenoxy) ethanesulfonate was obtained by a recrystallization method.

Example 4
Under argon atmosphere, in a flask, 86 ml of DMSO, 5.00 g (17.06 mmol) of sodium 3- (2,5-dichlorophenoxy) ethanesulfonate obtained in Synthesis Example 2, and the following polyethersulfone which is terminal chloro type
(Sumitomo Chemical Co., Ltd. Sumika Excel PES5200P, Mn = 5.44 × 10 ⁴ , Mw = 1.23 × 10 ⁵ ) 2.27 g, 10.31 g (65.999 mmol) of 2,2′-bipyridyl were added and stirred. The temperature was raised to 60 ° C. Next, 16.50 g (59.99 mmol) of nickel (0) bis (cyclooctadiene) was added thereto, the temperature was raised to 80 ° C., and the mixture was stirred at the same temperature for 17 hours. After allowing to cool, the polymer is precipitated by pouring the reaction solution into a large amount of 4N hydrochloric acid, filtered, washed with water until the filtrate is neutral, and then dried under reduced pressure to obtain the desired polyphenylene sulfonic acids. 73 g was obtained.
Mn = 93000, Mw = 186000
IEC = 2.35 meq / g (calculated as a / (a + ((n + 1) × b)) = 0.47)
Proton conductivity 1.44 × 10 ⁻¹ S / cm (DMSO was used for casting film formation)

Synthesis example 3
(Synthesis of sodium 3- (2,5-dichlorophenoxy) butanesulfonate)
Under an argon atmosphere, DMAc 150 ml, toluene 75 ml, 2,5-dichlorophenol 20.00 g (122.7 mmol), sodium carbonate 39.01 g (368.1 mmol) were placed in a flask, and the mixture was heated and stirred to azeotrope conditions of toluene and water. After dehydration below, toluene was distilled off. After allowing to cool to room temperature, 25.06 g (184.1 mmol) of butane sultone was added, the temperature was raised to 80 ° C., and the mixture was stirred at the same temperature for 10 hours. After allowing to cool, the solid was removed by suction filtration, a large amount of chloroform was added to the obtained filtrate, and the precipitated white solid was separated by filtration. Further, 38.7 g (98% yield) of sodium 3- (2,5-dichlorophenoxy) butanesulfonate was obtained by a recrystallization method.

Example 5
Under an argon atmosphere, the flask was charged with 85 ml of DMSO, 5.00 g (15.57 mmol) of sodium 3- (2,5-dichlorophenoxy) butanesulfonate obtained in Synthesis Example 3, and the following polyether sulfone having a terminal chloro type.
(Sumitomo Chemical Co., Ltd. SUMIKAEXCEL PES5200P, Mn = 5.44 × 10 ⁴ , Mw = 1.23 × 10 ⁵ ) 1.73 g, 2,2′-bipyridyl 8.06 g (51.62 mmol) was added and stirred. The temperature was raised to 60 ° C. Next, 12.91 g (46.92 mmol) of nickel (0) bis (cyclooctadiene) was added thereto, the temperature was raised to 80 ° C., and the mixture was stirred at the same temperature for 4 hours. After allowing to cool, the reaction solution is poured into a large amount of 4N hydrochloric acid to precipitate a polymer, filtered, washed with water until the filtrate is neutral, and then dried under reduced pressure to obtain the desired polyphenylene sulfonic acids. 21 g was obtained.
Mn = 130,000, Mw = 250,000
IEC = 2.67 meq / g (calculated as a / (a + ((n + 1) × b)) = 0.61)
Proton conductivity 2.98 × 10 ⁻¹ S / cm (DMSO was used for casting film formation)

Claims (12)

The following general formula (1)

(In the formula, X represents a direct bond, —O—, —S—, —SO—, —SO ₂ — or —CO—, and Y represents a direct bond, a divalent or trivalent aromatic group. R ¹ and R ² each independently represent a hydrogen atom or a fluorine atom, and R ³ each independently represent a sulfonic acid group, an alkyl group having 1 to 10 carbon atoms or a carbon number of 6 to 18 Represents an optionally substituted aryl group, i represents a number from 0 to 3, k represents a number from 1 to 12, l represents 1 when Y is a direct bond or divalent, and Y represents In the case of a trivalent aromatic group, it represents 2.)
A polyarylene polymer having a repeating structure represented by:   The polymer according to claim 1, wherein 90% or more of the repeating structure represented by the general formula (1) is bonded at the para position. Furthermore, the following general formulas (2) and (3)
(In the formula, Ar ¹ and Ar ² each independently represent a divalent aromatic group, where the divalent aromatic group is an alkyl group having 1 to 10 carbon atoms and 6 to 18 carbon atoms. It may be substituted with an aryl group or a sulfonic acid group, Z represents any of —O—, —SO ₂ —, and —CO—, m represents a number of 1 or more, and n represents a number of 0 or more. R ⁴ represents a sulfonic acid group, an alkyl group having 1 to 10 carbon atoms, an optionally substituted aryl group having 6 to 18 carbon atoms, or an acyl group having 2 to 20 carbon atoms, independently of each other. And p represents a number from 0 to 4.)
The polymer according to claim 1, wherein the polymer has at least one repeating structure represented by:   The polymer according to claim 3, wherein 90% or more of the repeating structure represented by the general formula (3) in the main chain is bonded at the para position.   The polymer according to any one of claims 1 to 4, wherein Y is a direct bond.   i is 0, The polymer in any one of Claims 1-5.   The polymer according to any one of claims 1 to 6, wherein the ion exchange capacity is 0.5 meq / g to 4 meq / g.   The polymer according to any one of claims 1 to 7, which is a random copolymer or a block copolymer.   A polymer electrolyte comprising the polymer according to claim 1 as an active ingredient.   A polymer electrolyte membrane comprising the polymer electrolyte according to claim 9.   A catalyst composition comprising the polymer electrolyte according to claim 9. A polymer electrolyte fuel cell comprising at least one selected from the polymer electrolyte according to claim 9, the polymer electrolyte membrane according to claim 10, and the catalyst composition according to claim 11.