JP4752318B2 - Polymer having oxocarbon group and use thereof - Google Patents

Description

  The present invention relates to a novel polymer having an oxocarbon group and use thereof.

Oxocarbons typified by squaric acid (square acid) are known to have high acidity because the state in which hydrogen in the oxocarbon group is dissociated has a stable structure due to resonance (Non-patent Document 1) ( Non-patent document 2).
On the other hand, a polymer having a sulfonic acid group is known to be useful as a polymer electrolyte for a polymer electrolyte fuel cell or the like. For example, fluorinated polymers such as Nafion (registered trademark of DuPont), polymers obtained by introducing sulfonic acid groups into polyether ketones (Patent Document 1), polymers obtained by introducing sulfonic acid groups into polyether sulfones (Non-patent Document 3), Polymers with sulfonic acid groups introduced into polyimides (Patent Document 2), Polymers with sulfonic acid groups introduced into polyphenylenes (Patent Document 3), and sulfonic acid groups introduced into polyphosphazenes The polymer (Non-patent Document 4) has been proposed as a polymer electrolyte for a polymer electrolyte fuel cell or the like.

Oxocarbons, p. 45 (Edited by Robert West), Academic Press (1980), (ISBN: 0-12-744580-3). Journal of the American Chemical Society, 95, 8703 (1973) J. et al. Membrane Science, 83, 211 (1993) Chemical Material, 3, 1120 (1991) US Pat. No. 5,438,082 (columns 2-6, 14-16) JP 2003-277501 A (pages 2 to 5) US Pat. No. 5,403,675 (columns 2-5, 15-16)

However, a polymer having an oxocarbon group is not known.
The inventors of the present invention have produced a polymer having an oxocarbon group and conducted various studies. As a result, the polymer having an oxocarbon group is a solid polymer that uses a gaseous fuel such as hydrogen gas or a liquid fuel such as methanol or dimethyl ether. It is useful as a polymer electrolyte that is a material for proton conductive membranes of molecular fuel cells, and has proton conductivity comparable to a polymer having a sulfonic acid group and a polymer having a sulfonic acid group. In comparison, the present inventors have found that the chemical stability and water resistance are excellent, and that high proton conductivity can be maintained for a long time.

（式中、Ｘ¹、Ｘ²はそれぞれ−Ｏ−を表し、Ｚは−ＣＯ−を表す。ｎは繰り返しの数を表わし、ｎ＝０〜４の数を表わす。ｎ個あるＺは同じであっても良いし、異なっていても良い。Ｂは水素原子を表す。） That is, the present invention provides [1] vinyl polymers, polyoxyalkylenes, polysiloxanes, polyesters, polyimides, polyamides, polybenzoxazoles, polybenzimidazoles, polyarylene ethers, polyarylenes, polyarylenes. One or more polymers selected from the group consisting of sulfides, polyether ketones, polyether sulfones, polyphosphazenes, and copolymers thereof, and an oxocarbon represented by the following general formula (1) have a group, in which the number-average molecular weight to provide a polymer, which is a 5,000 to 1,000,000.

(Wherein, X ^1, X ² are, respectively it - O - represents, Z is -CO - a representative .n represents the number of repeating, n = .n pieces is Z representing the number of 0-4 is may be the same, may be different .B represents a hydrogen atom.)

Furthermore, the present invention is
[2 ] The polymer according to [1 ] above, which has a phenyl-phenyl bond in the main chain,
[ 3 ] A polymer electrolyte containing the polymer according to [1] or [2] as an active ingredient,
[ 4 ] A polymer electrolyte membrane comprising the polymer electrolyte of [ 3 ] above,
[ 5 ] A catalyst composition comprising the polymer electrolyte of [ 3 ] above,
[ 6 ] A polymer electrolyte membrane-electrode assembly comprising any one of the polymer electrolyte of [ 3 ], the polymer electrolyte membrane of [ 4 ], and the catalyst composition of [ 5 ],
[ 7 ] It has any one of the polymer electrolyte of [ 3 ], the polymer electrolyte membrane of [ 4 ], the catalyst composition of [ 5 ], and the polymer electrolyte membrane-electrode assembly of [ 6 ]. The present invention provides a polymer electrolyte fuel cell.

  The polymer having an oxocarbon group of the present invention is useful as a polymer electrolyte that is a material for a proton conductive membrane of a polymer electrolyte fuel cell using a gaseous fuel such as hydrogen gas or a liquid fuel such as methanol or dimethyl ether. In particular, it has not only proton conductivity comparable to polymers having sulfonic acid groups, but also excellent chemical stability and water resistance compared to polymers having sulfonic acid groups, and high proton conductivity over a long period of time. Therefore, the polymer of the present invention is advantageous in practical use.

（式中、Ｘ¹、Ｘ²はそれぞれ独立に−Ｏ−、−Ｓ−又は−ＮＲ−を表し、Ｚは−ＣＯ−、−Ｃ（Ｓ）−、−Ｃ（ＮＲ）−、置換基を有していても良いアルキレン基又は置換基を有していても良いアリーレン基を表す。（ＮＲにおけるＲは，水素原子、置換基を有していてもよい炭素数１〜６のアルキル基又は置換基を有していてもよい炭素数６〜１０のアリール基を表す。）ｎは繰り返しの数を表わし、ｎ＝０〜１０の数を表わす。ｎ個あるＺは同じであっても良いし、異なっていても良い。Ｂは水素原子または１価の金属原子を表す。）
で示されるオキソカーボン基を有することを特徴とする。 Hereinafter, the present invention will be described in detail.
The polymer of the present invention has a free acid form represented by the following general formula (1)

(Wherein X ¹ and X ² each independently represent —O—, —S— or —NR—, Z represents —CO—, —C (S) —, —C (NR) —, a substituent, Represents an optionally substituted alkylene group or an optionally substituted arylene group (R in NR represents a hydrogen atom, an optionally substituted alkyl group having 1 to 6 carbon atoms, or Represents an aryl group having 6 to 10 carbon atoms which may have a substituent.) N represents the number of repetitions and represents a number of n = 0 to 10. The n Zs may be the same. And B represents a hydrogen atom or a monovalent metal atom.)
It has the oxocarbon group shown by these.

Here, X ¹ and X ² each independently represent —O—, —S—, or —NR—. -O- and -S- are preferable, and -O- is particularly preferable. R in NR has 1 to 6 carbon atoms which may have a substituent represented by a hydrogen atom, methyl group, trifluoromethyl group, ethyl group, propyl group, isopropyl group, n-butyl group and the like. It represents an aryl group having 6 to 10 carbon atoms which may have a substituent represented by an alkyl group, a phenyl group, a pentafluorophenyl group, a naphthyl group or the like.
Z represents -CO-, -C (S)-, -C (NR)-, an alkylene group which may have a substituent, or an arylene group which may have a substituent. R in NR has the same meaning as above.
Typical examples of the alkylene group which may have a substituent include methylene, fluoromethylene, difluoromethylene, phenylmethylene, diphenylmethylene and the like. Representative examples of the arylene group which may have a substituent include a phenylene group, a naphthylene group, a tetrafluorophenylene group, and the like.
Z is preferably —CO—, —C (S) —, —C (NR) —, more preferably —CO—, —C (S) —, and particularly preferably —CO—.
n represents the number of repetitions of Z, 0-10. The n Zs may be the same or different. n is preferably 0 to 4, more preferably 0 to 2, and most preferably 1.
B represents a hydrogen atom or a monovalent metal atom. Examples of the monovalent metal atom include a lithium atom, a sodium atom, a potassium atom, a cesium atom, and a silver atom. B is preferably a hydrogen atom, a lithium atom, or a sodium atom, more preferably a hydrogen atom or a lithium atom, and particularly preferably a hydrogen atom.

で表わされる平衡反応をとりうる。この平衡反応の極限構造は下記式

のように表わされ、プロトンが解離した時のカチオンが分子内に広く非局在化するために安定な構造である。そのために式（１）で表される化合物は酸性度が高い基になるものと考えられる。 In the group represented by the formula (1), when B is a hydrogen atom, that is, in the form of a free acid, the following formula

The equilibrium reaction represented by can be taken. The ultimate structure of this equilibrium reaction is

This is a stable structure because the cations when protons dissociate are widely delocalized in the molecule. Therefore, it is considered that the compound represented by the formula (1) becomes a group having high acidity.

等が挙げられる。 As a typical example of such a preferable oxocarbon group, for example,

Etc.

Among these, (1a) to (1d) are preferable. More preferred are (1a) to (1c), even more preferred are (1b) to (1c), and most preferred is (1b).
The oxocarbon group may be in the form of a free acid in which B is hydrogen, or in the form of a salt in which B is a monovalent metal atom. In the polymer having an oxocarbon group of the present invention, an oxocarbon group may be bonded to all of the repeating units, and a repeating unit to which no oxocarbon group is bonded may be present in the polymer. . Two or more oxocarbon groups may be bonded to the repeating unit. The oxocarbon groups bonded to the repeating units of these polymers may be the same or different from each other, and B in the general formula (1) may be hydrogen or a monovalent metal. When used as a material for a polymer electrolyte fuel cell, it is preferable that substantially all oxocarbon groups bonded to repeating units are in the form of a free acid from the viewpoint of power generation performance.
The monovalent metal is preferably a lithium atom, a sodium atom, or a potassium atom, more preferably a lithium atom or a sodium atom, and particularly preferably a lithium atom.

  The polymer of the present invention is characterized by having an oxocarbon group represented by the general formula (1). If the polymer has the oxocarbon group, the base polymer is particularly There is no limitation, for example, vinyl polymers, polyoxyalkylenes, polysiloxanes, polyesters, polyimides, polyamides, polybenzoxazoles, polybenzimidazoles, polyarylene ethers, polyarylenes, polyarylene sulfides , Polyether ketones, polyether sulfones, polyphosphazenes, and the like, and copolymers and mixtures thereof.

（式中、Ｒ¹〜Ｒ⁶は互いに独立に水素原子、フッ素原子、塩素原子、メチル基又はトリフルオロメチル基を表す。） Examples of the vinyl polymer having an oxocarbon group represented by the general formula (1) include the following. A represents the general formula (1), m, p and q represent the number of repetitions (the same applies hereinafter), where m is usually 20 or more, p is usually 0 to 3, and q is usually 1 ~ 5.

(In the formula, R ^{1 to} R ⁶ each independently represents a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group or a trifluoromethyl group.)

また、一般式（１）で示されるオキソカーボン基を有するポリエステルとしては、例えば下記の繰り返し単位にオキソカーボン基が結合した繰り返し単位を有する高分子が挙げられ、オキソカーボン基は下記繰り返し単位の置換可能な水素のいずれかを置換している。オキソカーボン基は芳香環上の水素を置換するのが好ましい。

（式中、Ｒ⁷、Ｒ⁸は互いに独立に水素原子、フッ素原子、塩素原子、メチル基、トリフルオロメチル基又はフェニル基を表す。） Examples of the polyoxyalkylene having an oxocarbon group represented by the general formula (1) and the polysiloxane having an oxocarbon group represented by the general formula (1) include polymers having the following repeating units.

Examples of the polyester having an oxocarbon group represented by the general formula (1) include a polymer having a repeating unit in which an oxocarbon group is bonded to the following repeating unit, and the oxocarbon group is a substitution of the following repeating unit. Replaces any of the possible hydrogens. The oxocarbon group preferably replaces a hydrogen on the aromatic ring.

(In the formula, R ⁷ and R ⁸ each independently represent a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, a trifluoromethyl group or a phenyl group.)

Examples of the polyimide having an oxocarbon group represented by the general formula (1) include a polymer having a repeating unit in which an oxocarbon group is bonded to the following repeating unit, and the oxocarbon group can be substituted with the following repeating unit. Replaces any of the hydrogens.

Further, a polyamide having an oxocarbon group represented by the general formula (1), a polybenzoxazole having an oxocarbon group represented by the general formula (1), a polybenzimidazole having an oxocarbon group represented by the general formula (1), Examples of the polyarylene ether having an oxocarbon group represented by the general formula (1) include a polymer having a repeating unit in which the oxocarbon group is bonded to the following repeating unit. Replaces any of the possible hydrogens.

Examples of the polyarylene having an oxocarbon group represented by the general formula (1) include a polymer having a repeating unit in which the oxocarbon group is bonded to the following repeating unit. The oxocarbon group can be substituted with the following repeating unit. One of the hydrogens is replaced.

The polyether ketone having an oxocarbon group represented by the general formula (1) includes, for example, a polymer having a repeating unit in which the oxocarbon group is bonded to the following repeating unit. Any of the replaceable hydrogens are replaced.

Examples of the polyethersulfone having an oxocarbon group represented by the general formula (1) include a polymer having a repeating unit in which an oxocarbon group is bonded to the following repeating unit, and the oxocarbon group is a substitution of the following repeating unit. Replaces any of the possible hydrogens.

（式中、Ｒ⁹、Ｒ¹⁰は互いに独立に水素原子、フッ素原子、塩素原子、メチル基、トリフルオロメチル基又はフェニル基を表す。）
上記例示繰り返し単位に結合するオキソカーボン基の数は一つでも２以上であってよい。繰り返し単位に結合しているオキソカーボン基は同じでも互いに異なっていてもよい。また高分子中の全ての繰り返し単位にオキソカーボン基が結合していなくてもよい。 Further, polyarylene sulfide having an oxocarbon group represented by the general formula (1), polyphthalazinone having an oxocarbon group represented by the general formula (1), and polyphosphazene having an oxocarbon group represented by the general formula (1) Examples thereof include a polymer having a repeating unit in which an oxocarbon group is bonded to the following repeating unit, and the oxocarbon group substitutes any substitutable hydrogen of the following repeating unit. A has the same meaning as described above.

(In the formula, R ⁹ and R ¹⁰ each independently represent a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, a trifluoromethyl group or a phenyl group.)
The number of oxocarbon groups bonded to the above exemplified repeating unit may be one or two or more. The oxocarbon groups bonded to the repeating unit may be the same or different from each other. Further, the oxocarbon group may not be bonded to all the repeating units in the polymer.

Among these polymers, vinyl polymers, polybenzoxazoles, polybenzimidazoles, polyarylene ethers, polyarylenes, polyether ketones, polyether sulfones, polyphosphazenes, etc. Polymers and mixtures thereof are preferred. More preferred are polyimides, polyarylenes, polyether ketones, polyether sulfones, and copolymers and mixtures thereof.
Even more preferred are polyarylenes, polyether ketones, polyether sulfones, and their copolymers, mixtures, etc., and most preferred are polyether sulfones.
Further, from the viewpoint of water resistance as a polymer electrolyte, a polymer having a phenyl-phenyl bond in the main chain as a base is preferable. Examples of such include polyarylenes, polyether sulfones having a phenyl-phenyl bond, polyether ketones having a phenyl-phenyl bond, and polyimides having a phenyl-phenyl bond, and most preferably Polyarylenes and polyether sulfones having a phenyl-phenyl bond.

The polymer of the present invention has the structure as described above, and the molecular weight thereof is not particularly limited, but is preferably about 5000 to 1000000, more preferably about 10000 to 500000, and particularly preferably about 20000 to 300000. . If it is less than 5000, it tends to be difficult to keep the film shape when used in the form of a film, and if it exceeds 1000000, it tends to be difficult to form the film shape.
The ion exchange capacity of the polymer of the present invention is preferably 0.5 meq / g to 8 meq / g. If it is less than 0.5 meq / g, the ionic conductivity tends to decrease, which is not preferable in terms of power generation characteristics, and if it exceeds 8 meq / g, it tends to be not preferable in terms of water resistance. The ion exchange capacity is preferably 0.6 to 7 meq / g, more preferably 0.7 to 6 meq / g, and most preferably 0.8 to 5 meq / g.

Next, the method for producing the polymer of the present invention will be described.
The polymer of the present invention is (A) a method for introducing an oxocarbon group of the general formula (1) into a polymer,
(B) The method etc. which superpose | polymerize and obtain the monomer containing the oxocarbon group of General formula (1) are mentioned.

In both methods (A) and (B),
(I) a method of synthesizing an aliphatic compound or an aromatic compound having a group of the general formula (1) using a lithium reagent (Journal of Organic Chemistry, 53 , 2482, 2477 (1988)),
(II) a method of synthesizing an aliphatic compound or an aromatic compound having a group of the general formula (1) using a Grignard reagent (Heterocycles, 27 (5), 1191 (1988)),
(III) A method of synthesizing an aliphatic compound or an aromatic compound having a group of the general formula (1) using a tin reagent (Journal of Organic Chemistry, 55 , 5359 (1990), Tetrahydron Letters, 31 (30), 4293 (1990)),
(IV) A method of synthesizing an aromatic compound having a group of the general formula (1) by using Friedel Crafts reaction (Synthesis, page 46 (1974))
Or the like. For example, the methods (I) to (IV) are applied, and the method of (A) is a method of bonding a group of the general formula (1) to a polymer having no group of the general formula (1). Examples of the method B) include a method of synthesizing an aliphatic compound or an aromatic compound having a group of the general formula (1) and polymerizing the obtained compound to obtain a target polymer.

For example, a method of introducing the oxocarbon group of the general formula (1) into the polymer of (A), specifically, a polymer having diphenylsulfone as a repeating unit, X ₁ = X ₂ = A method for introducing a structure of —O—, Z = —CO—, and n = 1 will be described.
A polymer having diphenylsulfone as a repeating unit in an inert gas is reacted with alkyllithium in a solution to generate an anion in the polymer, and 3,4-dialkoxy-3-cyclobutene-1,2- There is a method in which dione is reacted and further treated under acidic conditions.

の繰り返し単位を有する高分子を挙げることができる。ただし、ｍ、ｐは繰り返しの数を表わす。
アルキルリチウムとしてはメチルリチウム、エチルリチウム、ｎ−ブチルリチウム、ｓｅｃ−ブチルリチウム、ｔｅｒｔ−ブチルリチウム、フェニルリチウム、などを挙げることができる。 Here, as a polymer having diphenylsulfone as a repeating unit, for example,

And a polymer having a repeating unit of However, m and p represent the number of repetitions.
Examples of the alkyl lithium include methyl lithium, ethyl lithium, n-butyl lithium, sec-butyl lithium, tert-butyl lithium, and phenyl lithium.

As a solvent for the reaction, any solvent that does not react with alkyllithium and dissolves a polymer can be used without limitation. Examples of such solvents include ether solvents such as tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, 1,3-dioxane, tetrahydropyran, dibutyl ether, tert-butyl methyl ether, diphenyl ether, and crown ethers. Can be mentioned. Preferred are cyclic ethers such as tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, 1,3-dioxane and tetrahydropyran, particularly preferred are tetrahydrofuran and 1,3-dioxolane, and most preferred is tetrahydrofuran. . In addition, ether solvents, aliphatic hydrocarbon solvents and / or aromatic hydrocarbon solvents can also be used. Examples of the aliphatic solvent include cyclohexane, hexane, and heptane, and examples of the aromatic hydrocarbon solvent include benzene, toluene, and xylene.
The temperature at the time of reacting the alkyl lithium with the polymer is usually -150 ° C to 20 ° C, preferably -120 ° C to 0 ° C, more preferably -100 ° C to -20 ° C. The concentration of the solution when the alkyllithium and the polymer are reacted is usually 0.01 to 50 wt%, preferably 0.02 to 30 wt%, more preferably 0.1 to 20 wt%, particularly preferably 0.2 to 10 wt%. %, Most preferably 0.5-5 wt%. The reaction time for reacting the alkyl lithium with the polymer is usually 1 minute to 10 hours, preferably 2 minutes to 5 hours, more preferably 5 minutes to 4 hours, and particularly preferably 10 minutes to 3 hours.

  After generating an anion in the polymer as described above, 3,4-dialkoxy-3-cyclobutene-1,2-dione is reacted, but 3,4-dialkoxy-3-cyclobutene-1, used here, Examples of 2-dione include 3,4-dimethoxy-3-cyclobutene-1,2-dione, 3,4-diethoxy-3-cyclobutene-1,2-dione, and 3,4-di (n-propoxy)- 3-cyclobutene-1,2-dione, 3,4-diisopropoxy-3-cyclobutene-1,2-dione, 3,4-di (n-butoxy) -3-cyclobutene-1,2-dione, 3, , 4-Di (sec-butoxy) -3-cyclobutene-1,2-dione, 3,4-di (tert-butoxy) -3-cyclobutene-1,2-dione, 3,4-diphenoxy-3-cyclobutene − , Mention may be made of 2-dione, 3,4 Jinafutokishi 3-cyclobutene-1,2-dione. Of these, 3,4-dimethoxy-3-cyclobutene-1,2-dione, 3,4-diethoxy-3-cyclobutene-1,2-dione, 3,4-diisopropoxy-3-cyclobutene- 1,2-dione, 3,4-di (n-butoxy) -3-cyclobutene-1,2-dione.

  The reaction temperature when reacting such 3,4-dialkoxy-3-cyclobutene-1,2-dione is usually −150 ° C. to 20 ° C., preferably −120 ° C. to 0 ° C., more preferably − 100 ° C to -20 ° C. The reaction temperature is usually 1 minute to 10 hours, preferably 2 minutes to 5 hours, more preferably 5 minutes to 4 hours, and particularly preferably 10 minutes to 3 hours. The amount of 3,4-dialkoxy-3-cyclobutene-1,2-dione used in the reaction is preferably used in an equimolar amount or more with respect to the alkyllithium used.

Examples of the reagent used for treatment under acidic conditions include hydrochloric acid, sulfuric acid, nitric acid, acetic acid, trifluoroacetic acid, formic acid, oxalic acid, and mixtures thereof. As processing temperature, it is -150 degreeC-200 degreeC normally, Preferably it is -100 degreeC-150 degreeC, More preferably, it is -80 degreeC-120 degreeC. The treatment time is usually 10 minutes to 20 hours, preferably 30 minutes to 15 hours, and particularly preferably 1 hour to 10 hours. When treating under acidic conditions, it may be a homogeneous system or a heterogeneous system. If the polymer after processing is a heterogeneous system, it can be recovered by filtration, and if it is a homogeneous system, it can be recovered by precipitation in a poor solvent or a non-solvent and filtration.
The introduction rate of the oxocarbon group represented by the general formula (1) is easily controlled by the amount of alkyllithium used or the amount of 3,4-dialkoxy-3-cyclobutene-1,2-dione used. obtain.

Next, the case where the 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 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 preferably used. .
Specifically, the 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 polymer and can be removed thereafter, and N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), Aprotic polar solvents such as N-methyl-2-pyrrolidone (NMP) and dimethyl sulfoxide (DMSO), or chlorinated solvents such as dichloromethane, chloroform, 1,2-dichloroethane, chlorobenzene, dichlorobenzene, methanol, ethanol, propanol Alcohols such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether and other alkylene glycol monoalkyl ethers, tetrahydrofuran, 1,3-di Kisoran, 1,4-dioxane, 1,3-dioxane, tetrahydropyran, dibutyl ether, tert- butyl methyl ether, diphenyl ether, ether solvents such as crown ethers are preferably used. These can be used singly, but two or more solvents can be mixed and used as necessary.
Among them, dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, tetrahydrofuran, 1,3-dioxolane 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 polymer of the present invention. Also, other polymers can be combined with the polymer of the present invention by a method such as co-casting in the same solvent.
In fuel cell applications, it is also known to add inorganic or organic fine particles as a water retention agent in order to control the amount of water. Any of these known methods can be used as long as they are not contrary to the object of the present invention.
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 such as impregnating and compounding porous films and sheets, and reinforcing the film by mixing fibers and pulp, and these known methods are not contrary to the object of the present invention. Can be used.

Next, the fuel cell of the present invention will be described.
The fuel cell of the present invention can be produced by bonding a catalyst and a conductive material as a current collector to both surfaces of a 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 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 polymer electrolyte fuel cell.
The fuel cell of the present invention thus produced can be used in various forms using hydrogen gas, reformed hydrogen gas, methanol, dimethyl ether, etc. 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 weight was measured by gel permeation chromatography (GPC) by measuring the number average molecular weight (Mn) and / or the weight average molecular weight (Mw) in terms of polystyrene under the following conditions.
GPC measuring device HLC-8220 manufactured by TOSOH
Two columns KD-80M manufactured by Shodex are connected in series Column temperature 40 ° C
Mobile phase solvent DMAc (LiBr added to 10 mmol / dm ³ )
Solvent flow rate 0.5mL / min
Proton conductivity (σ) was measured as follows.
A platinum plate (width: 5.0 mm) was pressed against the surface of a strip-shaped film sample having a width of 1.0 cm so that the interval was 1.0 cm, and the sample was placed in a constant temperature and humidity chamber at 80 ° C. and relative humidity of 100%. It was hold | maintained, the alternating current impedance in 10 < ⁶ > -10 < ^-1 > Hz between platinum plates was measured, and it calculated | required from the following formula.
σ (S / cm) = 1 / (R × d)
(However, on the Cole-Cole plot, when the imaginary component of the complex impedance is 0, the real component of the complex impedance is R (Ω). D represents the film thickness (cm).)
The water absorption was determined by determining the increase in film weight after immersing the dried film in deionized water at 100 ° C. for 2 hours, based on the weight during drying.

(Reference Example 1) Production of 3-phenyl-4-hydroxycyclobutene-1,2-dione Under an argon atmosphere, 2 g (10.1 mmol) of diisopropyl squaric acid and 20 ml of dehydrated THF were placed in a flask to obtain a homogeneous solution. While maintaining at −78 ° C., 4.56 ml (10.3 mmol) of a phenyllithium dibutyl ether solution (19 wt%) was added dropwise over 15 minutes and allowed to react for 3 hours (TLC analysis (silica gel); hexane: ether = 5: 5 (vol / vol) and Rf = 0.37). After completion of the reaction, the reaction was stopped with 10 ml of water, and 10 ml of ether was added. The oil layer was separated and the aqueous layer was further extracted twice with methylene chloride. The oil layers were combined, dehydrated over anhydrous sodium sulfate, filtered and concentrated to obtain a yellow solid. This solid was dissolved in 0.2 ml of THF to obtain a uniform solution. When 1 ml of 36 wt% hydrochloric acid was added at room temperature, a yellow precipitate immediately formed. After reacting for 4 hours at room temperature, 50 ml of water was added. This was washed with methylene chloride three times, and water was distilled off to obtain a yellow solid. Purification by silica gel column (TLC analysis (silica gel); hexane: ether = 5: 5 (vol / vol), Rf = 0.00, THF Rf = 0.09), the desired 3-phenyl-4-hydroxycyclobutene -1,2-dione was obtained. The structure was confirmed by ¹ H NMR and ¹³ C NMR.

Reference Example 2 Cyclic Voltammetric Measurement of 3-Phenyl-4-hydroxycyclobutene-1,2-dione 83 mg of 3-phenyl-4-hydroxycyclobutene-1,2-dione synthesized in Reference Example 1 was deionized An aqueous solution of about 10 mM was prepared by dissolving in 50 ml of water. This aqueous solution was used as working electrode: glassy carbon. Reference electrode: Ag / AgCl / saturated KCl.
Counter electrode: platinum sweep range: -0.128 to 1.202 V (vs. Ag / AgCl / saturated KCl)
Cyclic voltammetry measurement was performed under the following conditions. As a result, in 3-phenyl-4-hydroxycyclobutene-1,2-dione, an oxidation wave was observed from about 1.3 V (vs. NHE) when converted to a standard hydrogen electrode. This means that this compound can exist stably in a fuel cell fueled with hydrogen or methanol.

(Reference Example 3) Evaluation of radical resistance of 3-phenyl-4-hydroxycyclobutene-1,2-dione by Fenton test 71.2 mg of FeCl ₂ .4H ₂ O was dissolved in 500 ml of deionized water. 4 ml of this solution and 36 ml of 3 wt% hydrogen peroxide water were mixed (Fenton reagent). Immediately after mixing, 10 mg of 3-phenyl-4-hydroxycyclobutene-1,2-dione synthesized in Reference Example 1 was added and dissolved uniformly, followed by stirring at 60 ° C. for 2 hours. Platinum was added to the test solution after the reaction to remove excess hydrogen peroxide. As a result of LC analysis (water / acetonitrile), 3-phenyl-4-hydroxycyclobutene-1,2-dione was hardly decomposed.

(Reference Example 4) Evaluation of radical resistance of benzenesulfonic acid by Fenton test The same test was conducted except that benzenesulfonic acid was used instead of 3-phenyl-4-hydroxycyclobutene-1,2-dione in Reference Example 3. went. As a result of LC analysis, benzenesulfonic acid was almost disappeared.

１．００ｇ（ユニット換算で２．２６ｍｍｏｌ）と脱水および脱酸素済みのテトラヒドロフラン（以下、ＴＨＦと略称する）８０ｍｌを入れ混合した。この溶液を−７８℃に保ち、ここにｎ−ＢｕＬｉ（１．６ＭのＨｅｘａｎｅ溶液）３．００ｍｌ（４．８０ｍｍｏｌ）を加え、１時間反応させた（これを溶液Ａと略称する）。
別の不活性ガス置換したフラスコに３，４−ジイソプロポキシ−３−シクロブテン−１，２−ジオン２．００ｇ（１０．１ｍｍｏｌ）と脱水および脱酸素済みのＴＨＦ２０ｍｌを入れて溶液とした。この溶液を−７８℃に保った（これを溶液Ｂと略称する）。
溶液Ａと溶液Ｂを−６０℃以下に保ったまま混合し、−７８℃で２時間反応させた。反応後、１２規定の塩酸１．０ｍｌを加えて反応を停止し、徐々に室温に昇温した後、ＴＨＦを留去した。デカンテーションで塩酸を除去し、水洗、乾燥して黄色のポリマーを得た。このポリマーをＴＨＦ５０ｍｌに溶解させ、ジエチルエーテル３００ｍｌに注いで析出させることにより精製した。精製したポリマーをフラスコ中で１２規定の塩酸５０ｍｌに分散させて１００℃で５時間反応させた。反応後、ポリマーをろ別、水洗、乾燥することにより目的のポリマー（Ｃ）を得た。得られたポリマーの分子量はＭｎ＝１０５０００であった。得られたポリマーを用いて、ＴＨＦ溶液からキャスト製膜し、厚さ５０μｍの強靭な膜（Ｄ）を得た。（Ｄ）のプロトン伝導度、イオン交換容量、吸水率を表１に示す。
得られたポリマー（Ｃ）は¹Ｈ ＮＭＲ、¹³Ｃ ＮＭＲ測定、イオン交換容量測定の結果、以下の構造を有していることが確認された。 Example 1
In the flask substituted with inert gas, the following polysulfone (manufactured by Aldrich)

1.00 g (2.26 mmol in terms of unit) and 80 ml of dehydrated and deoxygenated tetrahydrofuran (hereinafter abbreviated as THF) were added and mixed. This solution was kept at −78 ° C., and 3.00 ml (4.80 mmol) of n-BuLi (1.6M Hexane solution) was added thereto and reacted for 1 hour (this is abbreviated as Solution A).
In another inert gas-substituted flask, 2.00 g (10.1 mmol) of 3,4-diisopropoxy-3-cyclobutene-1,2-dione and 20 ml of dehydrated and deoxygenated THF were added to form a solution. This solution was kept at −78 ° C. (this is abbreviated as Solution B).
Solution A and Solution B were mixed while being kept at −60 ° C. or lower, and reacted at −78 ° C. for 2 hours. After the reaction, 1.0 ml of 12N hydrochloric acid was added to stop the reaction, the temperature was gradually raised to room temperature, and then THF was distilled off. Hydrochloric acid was removed by decantation, washed with water and dried to obtain a yellow polymer. This polymer was dissolved in 50 ml of THF and purified by pouring into 300 ml of diethyl ether for precipitation. The purified polymer was dispersed in 50 ml of 12N hydrochloric acid in a flask and reacted at 100 ° C. for 5 hours. After the reaction, the target polymer (C) was obtained by filtering the polymer, washing with water and drying. The molecular weight of the obtained polymer was Mn = 105000. The obtained polymer was cast into a film from a THF solution to obtain a tough film (D) having a thickness of 50 μm. Table 1 shows the proton conductivity, ion exchange capacity, and water absorption rate of (D).
As a result of ¹ H NMR, ¹³ C NMR measurement, and ion exchange capacity measurement, it was confirmed that the obtained polymer (C) had the following structure.

３．００ｇ（ユニット換算で７．５ｍｍｏｌ）と脱水および脱酸素済みの１，３−ジオキソラン３００ｍｌを入れ混合した。この溶液を−７８℃に保ち、ここにｎ−ＢｕＬｉ（１．６Ｍのヘキサン溶液）１１．３ｍｌ（１８ｍｍｏｌ）を加え、２時間反応させた（これを溶液Ｅと略称する）。
別の不活性ガス置換したフラスコに３，４−ジイソプロポキシ−３−シクロブテン−１，２−ジオン２．００ｇ（１０．１ｍｍｏｌ）と脱水および脱酸素済みの１，３−ジオキソラン１００ｍｌを入れて溶液とした。この溶液を−７８℃に保った（これを溶液Ｆと略称する）。
溶液Ｅと溶液Ｆを−６０℃以下に保ったまま混合し、−７８℃で２時間反応させた。反応後、１２規定の塩酸５．０ｍｌを加えて反応を停止し、徐々に室温に昇温した後、１，３−ジオキソランおよびヘキサンを留去した。デカンテーションで塩酸を除去し、水洗、乾燥して黄色のポリマーを得た。このポリマーをＮ，Ｎ−ジメチルアセトアミド１５０ｍｌに溶解させメタノール１０００ｍｌに注いで析出させることにより精製した。精製したポリマーをフラスコ中で１２規定の塩酸１５０ｍｌに分散させて１００℃で５時間反応させた。反応後、ポリマーをろ別、水洗、乾燥することにより目的のポリマー（Ｇ）を得た。このものの分子量はＭｎ＝９８０００であった。得られたポリマーを用いて、ＤＭＡｃ溶液からキャスト製膜し、厚さ２３μｍの強靭な膜（Ｈ）を得た。（Ｈ）のプロトン伝導度、イオン交換容量、吸水率を表１に示す。
得られたポリマー（Ｇ）は¹Ｈ ＮＭＲ、¹³Ｃ ＮＭＲ測定、イオン交換容量測定の結果、以下の構造を有していることが確認された。 Example 2
Polyphenylsulfone represented by the following structural formula (manufactured by Aldrich) in a flask purged with inert gas

3.00 g (7.5 mmol in terms of unit) and 300 ml of dehydrated and deoxygenated 1,3-dioxolane were added and mixed. This solution was kept at −78 ° C., and 11.3 ml (18 mmol) of n-BuLi (1.6 M hexane solution) was added thereto and reacted for 2 hours (this is abbreviated as Solution E).
Into another inert gas-substituted flask, 2.00 g (10.1 mmol) of 3,4-diisopropoxy-3-cyclobutene-1,2-dione and 100 ml of dehydrated and deoxygenated 1,3-dioxolane were placed. It was set as the solution. This solution was kept at −78 ° C. (this is abbreviated as Solution F).
Solution E and Solution F were mixed while being kept at −60 ° C. or lower, and reacted at −78 ° C. for 2 hours. After the reaction, 5.0 ml of 12N hydrochloric acid was added to stop the reaction, and the temperature was gradually raised to room temperature, and then 1,3-dioxolane and hexane were distilled off. Hydrochloric acid was removed by decantation, washed with water and dried to obtain a yellow polymer. This polymer was purified by dissolving in 150 ml of N, N-dimethylacetamide and pouring it into 1000 ml of methanol for precipitation. The purified polymer was dispersed in 150 ml of 12N hydrochloric acid in a flask and reacted at 100 ° C. for 5 hours. After the reaction, the target polymer (G) was obtained by filtering the polymer, washing with water and drying. The molecular weight of this product was Mn = 98000. The obtained polymer was cast from a DMAc solution to obtain a tough film (H) having a thickness of 23 μm. Table 1 shows the proton conductivity, ion exchange capacity, and water absorption rate of (H).
As a result of ¹ H NMR, ¹³ C NMR measurement, and ion exchange capacity measurement, the obtained polymer (G) was confirmed to have the following structure.

Example 3
In a flask purged with an inert gas, 0.506 g (2.76 mmol in terms of unit) of poly (4-bromostyrene) (manufactured by Aldrich) and 30 ml of dehydrated and deoxygenated THF were mixed to obtain a solution. This solution was kept at −78 ° C., and 5.33 ml (8.53 mmol) of nBuLi (1.6M hexane solution) was added thereto and reacted for 30 minutes (this is abbreviated as Solution I).
Into another flask purged with inert gas, 1.69 g (8.53 mmol) of 3,4-diisopropoxy-3-cyclobutene-1,2-dione and 20 ml of dehydrated and deoxygenated THF were added to form a solution. This solution was kept at −78 ° C. (this is abbreviated as Solution J).
Solution I and Solution J were mixed while being kept at -60 ° C or lower, and reacted at -78 ° C for 2 hours. After the reaction, 5.0 ml of 12N hydrochloric acid was added to stop the reaction, and the temperature was gradually raised to room temperature, and then tetrahydrofuran and hexane were distilled off. Hydrochloric acid was removed by decantation, washed with water and dried to obtain a yellow polymer. The polymer was thoroughly washed with methanol. The washed polymer was dispersed in 50 ml of 12N hydrochloric acid in a flask and reacted at 100 ° C. for 5 hours. After the reaction, the target polymer (K) was obtained by filtering the polymer, washing with water and drying. The molecular weight of this product was Mn = 141000. The obtained polymer was cast from a DMAc solution to obtain a tough film (L) having a thickness of 23 μm. Table 1 shows the proton conductivity, ion exchange capacity, and water absorption rate of (L).
As a result of ion exchange capacity measurement and elemental analysis, the obtained polymer (K) was confirmed to have the following structure.

Example 4
Into a flask purged with inert gas, 26.7 g (105 mmol) of 4,4′-dichlorodiphenylsulfone, 20.0 g (87.7 mmol) of 4,4′-dihydroxydiphenylsulfone, 13.3 g (96.4 mmol) of potassium carbonate, 206 g of N-methylpyrrolidone and 32 g of toluene were added, and the temperature was gradually raised to 150 ° C. to distill off the toluene. After the toluene was distilled off, the temperature was raised to 190 ° C., and the reaction was carried out at this temperature for 6 hours. Thereafter, the reaction solution was added to 1000 ml of methanol to precipitate a polymer, sufficiently washed with water and methanol, and dried to obtain a polymer (M). The molecular weight of the obtained polymer was Mn = 11000 and Mw = 23000.
Into a flask purged with inert gas, 5.00 g of sufficiently dried (M) and 100 ml of dehydrated and deoxygenated THF were added to make a homogeneous solution, and kept at −78 ° C., while maintaining n-butyllithium (1.6 M of 1.6 M). 17.0 ml of hexane solution was added dropwise. After dropping, the mixture was reacted at −78 ° C. for 60 minutes (this is abbreviated as Solution N).
In another inert gas-substituted flask, 6.89 g (34.8 mmol) of 3,4-diisopropoxy-3-cyclobutene-1,2-dione and 100 ml of dehydrated and deoxygenated THF were added to obtain a homogeneous solution. This solution was kept at −78 ° C., and 2.5 ml (5.65 mmol) of phenyl lithium (2.26 M dibutyl ether solution) was added dropwise for the purpose of removing the proton source in the system. The system was yellowish orange (this is abbreviated as Solution P).
Solution N and Solution P were mixed while being kept at −60 ° C. or lower, and reacted at −78 ° C. for 2 hours. After the reaction, 5.0 ml of 12N hydrochloric acid was added to stop the reaction, and the temperature was gradually raised to room temperature, and then tetrahydrofuran and hexane were distilled off. Hydrochloric acid was removed by decantation, washed with water and dried to obtain a yellow polymer. The polymer was thoroughly washed with methanol. The washed polymer was dispersed in 50 ml of 12N hydrochloric acid in a flask and reacted at 100 ° C. for 5 hours. After the reaction, the polymer (Q) was obtained by filtering the polymer, washing with water and drying. As a result of ¹ H NMR and ion exchange capacity measurement, the polymer (Q) was confirmed to have the following structure. The molecular weight of the obtained polymer was Mn = 17500 and Mw = 40000.

上記で得られたポリマー（Ｑ）１．５０ｇを２Ｎの水酸化カリウム水溶液１００ｍｌ中に１２時間分散させ、ろ過後、水洗を十分に行い、乾燥することでポリマー（Ｒ）を得た。得られたポリマーの分子量はＭｎ＝１９０００、Ｍｗ＝４００００であった。また、イオン交換容量測定の結果、実質的にすべてのオキソカーボン基がカリウム塩型になっていることが確認された。
不活性ガス置換したフラスコにポリマー（Ｒ）０．５０ｇ、ポリマー（Ｍ）０．５０ｇ、ジメチルスルホキシド１４ｍｌ、トルエン１０ｍｌ、２，２’−ビピリジル１２５ｍｇ（０．８００ｍｍｏｌ）を入れて、徐々に１５０℃に昇温してトルエンを留去した。その後、６０℃に温度を下げて、ビス（１，５−シクロオクタジエン）ニッケル（０）０．２００ｇ（０．７２７ｍｍｏｌ）を加えて、６０℃で６時間反応を行った。反応後、溶液を６規定の塩酸１００ｍｌに注いでポリマーを析出させた。このポリマーをＴＨＦに再溶解させて６規定の塩酸に注ぐ、という再沈殿の操作を５回繰り返すことで精製し、乾燥して、実質的にオキソカーボン基を有さないブロックとオキソカーボン基を有するブロックからなるブロック共重合体（Ｓ）を得た。このものの分子量はＭｎ＝４１０００、Ｍｗ＝２８４０００であった。得られたポリマーを用いて、ＴＨＦ溶液からキャスト製膜し、厚さ４３μｍの強靭な膜（Ｔ）を得た。（Ｔ）のプロトン伝導度、イオン交換容量、吸水率を表１に示す。得られたブロック共重合体（Ｓ）は以下の構造を有していることが確認された。

1.50 g of the polymer (Q) obtained above was dispersed in 100 ml of 2N aqueous potassium hydroxide solution for 12 hours, filtered, washed thoroughly with water, and dried to obtain polymer (R). The molecular weight of the obtained polymer was Mn = 19000 and Mw = 40000. As a result of measuring the ion exchange capacity, it was confirmed that substantially all oxocarbon groups were in the potassium salt form.
Polymer (R) 0.50 g, polymer (M) 0.50 g, dimethyl sulfoxide 14 ml, toluene 10 ml, 2,2′-bipyridyl 125 mg (0.800 mmol) were placed in a flask purged with inert gas, and gradually cooled to 150 ° C. The toluene was distilled off. Thereafter, the temperature was lowered to 60 ° C., 0.200 g (0.727 mmol) of bis (1,5-cyclooctadiene) nickel (0) was added, and the reaction was performed at 60 ° C. for 6 hours. After the reaction, the solution was poured into 100 ml of 6N hydrochloric acid to precipitate a polymer. The polymer is purified by repeating the reprecipitation operation of re-dissolving the polymer in THF and pouring into 6N hydrochloric acid 5 times, and drying to remove the block having substantially no oxocarbon group and the oxocarbon group. A block copolymer (S) consisting of the blocks having was obtained. The molecular weight of this product was Mn = 41000 and Mw = 284000. The obtained polymer was cast into a film from a THF solution to obtain a tough film (T) having a thickness of 43 μm. Table 1 shows the proton conductivity, ion exchange capacity, and water absorption of (T). It was confirmed that the obtained block copolymer (S) had the following structure.

Comparative Example 1
In the flask, 1.00 g (2.26 mmol in terms of unit) of the same polysulfone used in Example 1 and 10 ml of concentrated sulfuric acid (97 wt%) were added and stirred at room temperature. Three hours after the start of stirring, the reaction mass was poured into a large amount of ice water to precipitate a polymer. The precipitated polymer was washed with water and dried until the washing solution became neutral. This polymer was dissolved in DMAc and cast into a film. Proton conductivity could not be measured because the obtained membrane (b) did not have sufficient membrane strength. Further, (b) was easily dissolved in water at 100 ° C. Table 1 shows the ion exchange capacity of (b).
As a result of ¹ H NMR, ¹³ C NMR measurement and ion exchange capacity measurement, the obtained polymer was confirmed to have the following structure.

  The polymer having an oxocarbon group of the present invention is useful as a polymer electrolyte that is a material for a proton conductive membrane of a polymer electrolyte fuel cell using a gaseous fuel such as hydrogen gas or a liquid fuel such as methanol or dimethyl ether. The polymer of the present invention not only has proton conductivity comparable to a polymer having a sulfonic acid group, but also has excellent chemical stability, water resistance, etc. compared to a polymer having a sulfonic acid group, High proton conductivity can be maintained.

Claims (7)

Vinyl polymers, polyoxyalkylenes, polysiloxanes, polyesters, polyimides, polyamides, polybenzoxazoles, polybenzimidazoles, polyarylene ethers, polyarylenes, polyarylene sulfides, polyether ketones , polyethersulfones, polyphosphazenes, and then one or more polymers selected from the group consisting of a copolymer as a matrix, have a oxocarbon group represented by the following general formula (1), number average A polymer having a molecular weight of 5,000 to 1,000,000 .

(Wherein, X ^1, X ² are, respectively it - O - represents, Z is -CO - a representative .n represents the number of repeating, n = .n pieces is Z representing the number of 0-4 is may be the same, may be different .B represents a hydrogen atom.) Phenyl in the main chain - claim 1 Symbol placement of the polymer and having a phenyl bond. Claim 1 or 2 polyelectrolyte as an active ingredient a polymer according. A polymer electrolyte membrane comprising the polymer electrolyte according to claim 3 . A catalyst composition comprising the polymer electrolyte according to claim 3 . Polyelectrolyte according to claim 3, wherein the polymer electrolyte membrane according to claim 4, wherein the polymer electrolyte membrane and having any of the claims 5 A catalyst composition according - electrode assembly. Polyelectrolyte according to claim 3, wherein the polymer electrolyte membrane according to claim 4, wherein the catalyst composition according to claim 5, wherein the polymer electrolyte membrane of claim 6, wherein - the feature that it has one of the electrode assembly A polymer electrolyte fuel cell.