JP2003206402A - Polymer electrolyte composition and its use - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a polymer electrolyte exhibiting proton conductivity under a high-temperature condition at ≥100°C. <P>SOLUTION: This polymer electrolyte composition comprises a phosphorus polymer compound represented by general formula (1) (Z is SO<SB>2</SB>or CO; x and y are each 0.01-0.99 and x+y is 1; Ar is a 4-18C bifunctional aromatic group which may contain a heteroelement and Ar may contain a substituent; n is the average number of substituents per unit structure of a polymer part containing the aromatic group and n is a positive number of ≤8; R and R' are each independently a hydrogen atom or an alkyl group) and a phosphoric acid represented by general formula (2): O=P (R'''O)<SB>k</SB>(OH)<SB>3-k</SB>(R''' is a 1-6C alkyl group or an aryl group; k is 0-2 and when k is 2, two Rs'''s may be the same or different). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a composition containing a phosphorus-based polymer compound and phosphoric acid, and more specifically, to a phosphorus-based polymer having a phosphonic acid group or the like directly bonded to an aromatic ring. The present invention relates to a composition comprising a molecular compound and phosphoric acid.

[0002]

2. Description of the Related Art In recent years, fuel cells have been attracting attention as a highly efficient and clean energy conversion device. Among them, a polymer electrolyte fuel cell using a polymer membrane having proton conductivity as an electrolyte is a compact structure, can provide high output, and can be operated by a simple system, and thus is used as a mobile power source for vehicles. Attention has been paid.

For example, as a solid polymer electrolyte exhibiting stable proton conductivity even under high temperature conditions of 100 ° C. or higher, a phosphorus-based polymer in which a methylenephosphonic acid group or the like is introduced into an aromatic polymer compound such as polyphenylene ether. A polymer electrolyte composition comprising a polymer compound, that is, a phosphorus-based polymer compound in which a phosphonic acid group or the like is bonded to an aromatic ring via a methylene group, and phosphoric acid has been proposed (Tokuhokuhei 11).
No. 503262). However, neither a phosphorus-based polymer compound in which a phosphonic acid group or the like is directly bonded to an aromatic ring without a methylene group, nor a composition comprising this compound and phosphoric acid is known.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies in order to provide a polymer composition comprising a phosphorus-based polymer compound having a phosphonic acid group or the like directly bonded to an aromatic ring and phosphoric acid. As a result, a phosphorus-based polymer compound in which a phosphonic acid group or the like is directly bonded to an aromatic ring can be easily produced, and a polymer composition composed of this compound and phosphoric acid has a proton conductivity even under high temperature conditions of 100 ° C or higher. In addition to finding that it can be a solid polymer electrolyte exhibiting the following, a solid polymer electrolyte containing phosphoric acid in an amount of 2 equivalents or more with respect to the phosphorus atom-equivalent mole number of a phosphorus-based polymer compound is more excellent and stable in proton conductivity. The present invention has been completed by finding that

That is, the present invention provides a polymer electrolyte composition containing a phosphorus-based polymer compound represented by the general formula (1) and a phosphoric acid represented by the general formula (2). It is provided. (Wherein, -Z- is -SO ₂ - represents or -CO-, x and y represent the 0.01 to 0.99, respectively, the sum of x and y is 1.-Ar- hetero element Represents a divalent aromatic group having 4 to 18 carbon atoms, which may include
Ar- may have a substituent. n represents the average number of substituents per unit structure of the polymer portion containing an aromatic group, and n represents a positive number of 8 or less. R and R ′ each independently represent a hydrogen atom or an alkyl group. ) O = P (R ′ ″ O) _k (OH) _3−k (2) (In the formula, R ′ ″ represents an alkyl group or an aryl group having 1 to 6 carbon atoms. _K represents 0 to 2) When k is 2,
Two R ″ ′ s may be the same or different. )

The present invention also provides the above composition, which contains phosphoric acid in an amount of 2 equivalents or more based on the number of moles of the phosphorus-containing polymer compound in terms of phosphorus atom. It is intended to be used for.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail. The phosphorus-based polymer compound used in the present invention is represented by the above general formula (1), wherein -Z- is-.
SO ₂ − or —CO—, wherein x and y are 0.
01 to 0.99, and the sum of x and y is 1. −
Ar- represents a divalent aromatic group having 4 to 18 carbon atoms which may contain a hetero element, and -Ar- may have a substituent. n represents the average number of substituents per unit structure of the polymer portion containing an aromatic group, and n represents a positive number of 8 or less. R and R'each independently represent a hydrogen atom or an alkyl group.

Typical examples of --Ar-- include the following divalent groups. o-phenylene group, m-phenylene group, p-phenylene group, naphthalene-1,4-diyl group, naphthalene-1,5-diyl group,
Naphthalene-2,6-diyl group, naphthalene-2,3-
Diyl group, biphenyl-4,4'-diyl group, biphenyl-3,3'-diyl group, p-terphenyl-4,4 ''
-Diyl group, 2,2-diphenylpropane-4 ', 4''
A hydrocarbon-based divalent group such as -diyl group, fluorene-2,7-diyl group and fluorene-3,6-diyl group;

Carbazole-2,7-diyl group, carbazole-3,6-diyl group, thiophene-2,5-diyl group, dibenzothiophene-2,7-diyl group, furan-2,5-diyl group, dibenzofuran -2,7-diyl group, dibenzofuran-3,6-diyl group, diphenylamine-4,4'-diyl group, diphenylether-4,
A divalent group containing a hetero atom such as a 4'-diyl group.

Further, these groups may have a substituent, and examples of such a substituent include the following. Methyl group, ethyl group, 2-propyl group, t
-A linear or branched alkyl group which may be substituted with a hydroxyl group or a halogen atom, such as a butyl group, a hydroxymethyl group and a trifluoromethyl group; a methoxy group,
A linear or branched alkoxy group which may be substituted with a halogen atom, such as an ethoxy group or a trifluoromethoxy group; a phenyl group, a methylphenyl group, a methoxyphenyl group, a biphenyl group, a phenoxyphenyl group, a chlorophenyl group, Alkyl groups such as sulfophenyl groups,
Alkoxy group, phenyl group, phenoxy group, phenyl group which may be substituted with halogen atom or sulfonic acid group; alkyl group such as phenoxy group, methylphenoxy group, methoxyphenoxy group and sulfophenoxy group

Phenoxy group which may be substituted with alkoxy group or sulfonic acid group; alkyloxycarbonyl group such as ethoxycarbonyl group; alkylcarbonyloxy group such as ethylcarbonyloxy group; aminocarboxy group or N-alkylaminocarboxy group An amino group such as an amino group or a dimethylamino group in which a nitrogen atom may be substituted with an alkyl group; a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom or an iodine atom; a ureido group; an acylamino group; a carboxyl group; Examples thereof include a hydroxy group; a cyano group; a sulfonic acid group; and an aminosulfonyl group.

Preferred examples of --Ar-- in the present invention include, for example, o-phenylene (1,2-phenylene) group, m-phenylene (1,3-phenylene) group, p
-Phenylene (1,4-phenylene) group, 3-methyl-
1,2-phenylene group, 3-ethyl-1,2-phenylene group, 3-methoxy-1,2-phenylene group, 3-ethoxy-1,2-phenylene group, 3-bromo-1,2-phenylene group , 3-chloro-1,2-phenylene group, 3,
6-dimethyl-1,2-phenylene group, 4,5-dibromo-1,2-phenylene group, 2-methyl-1,3-phenylene group, 2-ethyl-1,3-phenylene group, 2-methoxy- 1,3-phenylene group, 2-ethoxy-1,3-
Phenylene group, 2-bromo-1,3-phenylene group, 2
-Chloro-1,3-phenylene group, 5-methyl-1,3
-Phenylene group, 5-bromo-1,3-phenylene group, 2
-Methyl-1,4-phenylene group, 2-ethyl-1,4
-Phenylene group, 2-methoxy-1,4-phenylene group, 2-ethoxy-1,4-phenylene group, 2-bromo-1,4-phenylene group, 2-chloro-1,4-phenylene group, 2, 6-dimethyl-1,4-phenylene group,
2,6-dibromo-1,4-phenylene group, 2-phenyl-1,4-phenylene group, 2,3-diphenyl-1,
An optionally substituted phenylene group such as 4-phenylene group,

Biphenyl-4,4'-diyl group, biphenyl-3,3'-diyl group, 3,3'-diphenylbiphenyl-4,4'-diyl group, 3,3'-bisphenoxybiphenyl-4, 4'-diyl group, 3,3'-dichlorobiphenyl-4,4'-diyl group, 3,3'-dibromobiphenyl-4,4'-diyl group, 2,2'-dichlorobiphenyl-3,3 ' -Diyl group, 2,2'-dibromobiphenyl-3,3'-diyl group, 4,4'-dichlorobiphenyl-
3,3'-diyl group, 4,4'-dibromobiphenyl-
Optionally substituted biphenyldiyl group such as 3,3′-diyl group, carbazole-2,2′-diyl group, carbazole-3,3′-diyl group, N-ethylcarbazole-2,2′-diyl group Group, N-ethylcarbazole-
Examples thereof include an optionally substituted carbazolediyl group such as a 3,3′-diyl group.

Among them, -Ar- is preferably a phenylene group which may be substituted or a biphenyldiyl group which may be substituted, m-phenylene group and p-
A phenylene group, a biphenyl-4,4'-diyl group, a biphenyl-3,3'-diyl group and the like are particularly preferable.

X and y mean the molar ratio of the comonomer used in the synthesis of the copolymer in the copolymer, and each represents 0.01 to 0.99, and the sum of x and y is 1. is there. Preferably y is 0.1 to 0.9.

R and R'independently represent a hydrogen atom or an alkyl group. Representative examples of alkyl groups include, for example, methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, t-butyl, t-pentyl, i-
Octyl, t-octyl, 2-ethylhexyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, 1-methylcyclopentyl, 1-methylcyclohexyl, 1-methyl-4-i-propylcyclohexyl, nonyl,
Decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, icosyl and the like having 1 to 22 carbon atoms
But not limited thereto.

In the phosphorus polymer compound represented by the general formula (1), one of R and R'is preferably a hydrogen atom, and more preferably both are hydrogen atoms. When R and / or R ′ is a hydrogen atom, it may be a salt or partially converted into a salt. In this case, examples of the cation include alkali metal ions and alkaline earth metal ions, particularly lithium, sodium,
Potassium is preferred.

The phosphorus polymer compound (1) may be a random copolymer, an alternating copolymer or a block copolymer. These can be produced by combining known methods. These polymerization degree is not particularly limited, usually 10 to 10 ⁴ nm, typically 1 to the molecular weight
Something from 0 ³ to 10 ⁶ is used. If the degree of polymerization is less than 10, the mechanical strength tends to be low, which may cause a problem in film formability, and if it exceeds 10 ⁴ , the solubility in a solvent tends to decrease, and cast film formation, etc. Since there is a possibility that problems may occur in the workability and moldability of (1), both cases are not preferable.

The method for producing the phosphorus-based polymer compound represented by the general formula (1) as described above is not particularly limited, but it can be produced, for example, by the following method.

First, the general formula (3) (In the formula, -Z-, x, y, and -Ar- have the same meanings as described above.) The aromatic polymer compound represented by the formula is brominated with a brominating agent. The obtained brominated compound is treated with a trialkyl phosphite (P (OR) (OR ') (OR ^″ )) in the presence of a nickel halide catalyst in an organic solvent to give phosphorus in the form of phosphonic acid diester. The polymer compound (1) can be produced. In addition, the diester can be hydrolyzed, if necessary, to produce the phosphorous polymer compound (1) in the form of phosphonic acid. Incidentally, the compound of the general formula (3) is, for example, Amoco
Commercially available products such as Polymer's Radel (registered trademark) can be used.

First, the step of brominating the aromatic polymer compound (3) with a brominating agent will be described. The bromination step is usually carried out by reacting the aromatic polymer compound (3) with a brominating agent such as bromine or N-bromosuccinimide in an organic solvent. Examples of the organic solvent used here include methylene chloride, chloroform, carbon tetrachloride, acetic acid and a mixed solvent thereof. In selecting the organic solvent, it is preferable that the solubility of the aromatic polymer compound (3) used is as high as possible. The reaction may be carried out at room temperature to the reflux temperature of the solvent, but if necessary, it may be cooled to room temperature or lower.
Further, a catalyst such as iron powder may be used.

As the brominating agent, it is preferable to use N-bromosuccinimide, and in this case, it is preferable to make a strong acid coexist. Here, examples of the strong acid include mineral acids such as sulfuric acid and hydrochloric acid, and organic acids such as trifluoroacetic acid, and sulfuric acid is preferably used. The ratio of the strong acid to the organic solvent is usually 0.3 to 20 times by weight, preferably 5 to 10 times by weight the organic solvent with respect to the strong acid. The organic solvent is usually used in an amount of 5 to 50 times, preferably 10 to 30 times the weight of the aromatic polymer compound. In addition, N-bromosuccinimide is usually 0.1 to 30 times by weight that of the aromatic polymer compound,
It is preferably used in an amount of 1 to 10 times by weight. Mixing can be done in any order. A method of adding an aromatic polymer compound and N-bromosuccinimide, which is a brominating reagent, to a mixture of a strong acid and an organic solvent in advance may be used. A method of gradually adding a strong acid such as sulfuric acid to a solvent solution or a slurry is preferable. When N-bromosuccinimide is used, the bromination is usually performed in the range of 0 ° C to 30 ° C. If the reaction temperature is too high, the sulfonation reaction may proceed when sulfuric acid is used as the strong acid.

As a method for extracting and purifying the brominated aromatic polymer compound, a usual method can be used. For example, a brominated aromatic polymer compound is precipitated by adding a poor solvent, the target product is taken out by filtration, etc., and then washed with water, reprecipitation purification using a good solvent and a poor solvent, etc. It can be carried out. The bromination degree of an aromatic polymer compound is
It can be determined by usual means such as NMR measurement and organic element analysis.

Next, a method for producing a phosphonic acid diester by causing a trialkyl phosphite to act on a brominated aromatic polymer compound will be described. This step is usually carried out in the presence of a nickel halide catalyst in an organic solvent, and the organic solvent used here is preferably an amide compound, and examples thereof include N, N-dimethylformamide and N, N-dimethyl. Examples include acetamide and N-methylpyrrolidone. Among them, N, N-dimethylformamide is particularly preferable. In selecting an organic solvent, it is preferable that the solubility of the brominated aromatic polymer compound used as a substrate is as high as possible. The organic solvent is usually used in an amount of about 3 to 100 times by weight that of the brominated aromatic polymer compound. It is preferably about 4 to 20 times by weight.

As the nickel halide catalyst, nickel (II) compounds are preferable, and nickel (II) chloride is particularly preferably used. The nickel halide catalyst is usually used in about 1 to 3 mole times in terms of bromo with respect to the brominated aromatic polymer compound. Preferably
It is about 1.5 to 2 mole times. When it is less than 1 mol times, the amount of bromine groups remaining is increased. Trialkyl phosphite (P (O
R) (OR ′) (OR ^″ )) is an alkyl moiety R,
The carbon number of R'and R ^'' is 1-22. Of these, the alkyl moiety is preferably a linear or branched alkyl group having 4 or less carbon atoms, and the alkyl groups may be different or the same. More preferred are trimethyl phosphite, triethyl phosphite and the like. Trialkyl phosphite is usually about 1.2 to 2 mole times with respect to the nickel halide catalyst, and 1.2 to bromo-converted with respect to the brominated aromatic polymer compound.
It is used about 5 times.

In the reaction of this step, usually, a brominated aromatic polymer compound and nickel halide are added to an organic solvent, the mixture is heated and stirred until the reaction mixture turns blue, and then trialkyl phosphite is added. It is carried out by.
Here, the reaction temperature with the trialkyl phosphite is 90 ° C.
The above is preferable, and when N, N-dimethylformamide is used as the organic solvent, it is more preferable to carry out under reflux. By adopting such conditions,
The conversion rate from bromo group to phosphonic acid diester can be improved. The reaction time depends on the kind of the brominated aromatic polymer compound, the solvent, the temperature, etc., but when the reaction is carried out at reflux using N, N-dimethylformamide as a solvent, it is usually 1 to It is about 24 hours. When the phosphorus-based polymer compound (1) in the form of phosphonic acid diester is taken out from the reaction mixture and purified, a usual method can be used. For example, a method of precipitating a phosphonic acid diester by adding a poor solvent, taking out an intended product by filtration, a method of purifying by washing with water, reprecipitation using a good solvent and a poor solvent, and the like are possible. Can be mentioned.

Next, a method for producing the phosphorous polymer compound (1) in the form of phosphonic acid by hydrolyzing the phosphorous polymer compound (1) in the form of phosphonic acid diester will be described. Hydrolysis of phosphonate diesters
The process may be carried out after the phosphonic acid diester is once taken out from the reaction mixture, or may be carried out by subsequently adding a hydrolysis reagent to the reaction mixture. The hydrolysis method may be based on various known methods. For example, a method of mixing and heating an aqueous solution of sodium hydroxide, potassium hydroxide or the like with a phosphonic acid diester dissolved or partially dissolved in an amide-based or ether-based solvent, or a trialkylsilyl ester such as trimethylsilyl iodide in the phosphonic acid diester. After reacting with a halide, a method of adding water for hydrolysis (Tetrahedron Lett. No. 2, 1977 , 155-158,
JCS Chem. Comm., 1978 , 870-871.), A method of hydrolysis using an aqueous solution of an acid, and the like. In the method (1), a monohydrolyzate of a diester (phosphonic acid monoester, one of R and R'is an alkyl group and the other is a hydrogen atom) is mainly used.
Both R'are hydrogen atoms).

As an example of the hydrolysis method (1), an aqueous solution containing an alkali in a molar excess of 1 mol or more in terms of phosphonate ester group, usually in large excess, and a phosphonate diester are dissolved or partially dissolved in an amide-based or ether-based solvent. An example is a method in which the mixed solution is mixed so that the phosphonic acid diester is at least partially dissolved, and the mixture is carried out at the reflux temperature of the mixture. As an example of the hydrolysis method of, a mixed solution of phosphonic acid diester dissolved or partially dissolved in an amide-based or ether-based solvent is cooled at about -50 ° C to room temperature, and a trialkyl halide is converted to phosphonic acid. In 2
An example is a method in which about 10 to 10 mol times are added, and then the temperature is kept at about 0 to 100 ° C., and then water is added to keep the temperature at 0 to 100 ° C.
Of course, after reacting the trialkylsilyl halide,
Alternatively, a method of once taking out and hydrolyzing in water or a mixed solution of water and an organic solvent may be used. Further, as an example of the hydrolysis method, a method of stirring a mixed solution of phosphonic acid diester dissolved or slurried in a solvent containing an aqueous hydrochloric acid solution at room temperature to reflux temperature, preferably at 80 ° C to reflux temperature can be exemplified. As a solvent containing aqueous hydrochloric acid, 10 to 35%
Examples of the aqueous solution of hydrochloric acid and a mixed solvent of the aqueous solution and another solvent include alcohols, ketones, aprotic solvents such as dimethyl sulfoxide and N, N-dimethylformamide, and the like.

Phosphoric acid high molecular compound in the form of phosphonic acid monoester and / or phosphonic acid formed (1)
Can be removed from the reaction mixture by conventional methods. For example, a target solvent can be taken out by precipitating phosphonic acids by adding a poor solvent and filtering. If necessary, it can be further purified by a usual purification method such as washing with water or reprecipitation using a good solvent and a poor solvent. The phosphorus-based polymer compound (1) in these forms may be a salt or a partial salt. In this case, examples of the cation include an alkali metal ion and an alkaline earth metal ion, particularly lithium, sodium,
Potassium is preferred.

The polymer electrolyte composition of the present invention is characterized by containing the phosphorus-based polymer compound (1) as described above and the phosphoric acid represented by the general formula (2). is there. Here, in the formula (2), R ′ ″ represents an alkyl group or an aryl group having 1 to 6 carbon atoms, and k represents 0 to 2. When k is 2, two R ′ ″ s may be the same or different. k is preferably 0 or 1,
It is more preferably 0. If k is 1 or 2, then
R ′ ″ is preferably an alkyl group. Examples of the alkyl group include methyl, ethyl, propyl, i-
Examples thereof include linear, branched or cyclic alkyl groups such as propyl, n-butyl, I-butyl, sec-butyl, pentyl, cyclopentyl, hexyl and cyclohexyl. The alkyl group may have groups such as a halogen atom, an amino group and a hydroxy group.

Examples of the aryl group include alkyl-substituted phenyl groups such as phenyl group, tolyl group, ethylphenyl group and isopropylphenyl group, halogen-substituted phenyl groups such as bromophenyl group, naphthyl group, anthryl group, phenanthryl group, nitrophenyl group, A chlorophenyl group etc. are mentioned.

Examples of phosphoric acids in which R ″ ′ is an alkyl group and k is 1 include phosphoric acid monomethyl ester, phosphoric acid monoethyl ester, phosphoric acid mono n-propyl ester, phosphoric acid monoisopropyl ester, phosphoric acid monoisopropyl ester. n-Butyl ester, phosphoric acid monoisobutyl ester, phosphoric acid mono sec-butyl ester, phosphoric acid mono tert-butyl ester, phosphoric acid mono n-pentyl ester, phosphoric acid mono (1-methylbutyl) ester, phosphoric acid mono (2 -Methylbutyl) ester, phosphoric acid mono (3-methylbutyl) ester, phosphoric acid mono (1,1-dimethylpropyl) ester, phosphoric acid mono (2,2-dimethylpropyl) ester, phosphoric acid mono (1,2-dimethyl) Propyl) ester, phosphoric acid mono-n-hexyl ester, phosphoric acid mono (2-methylpentyl) ) Ester, phosphoric acid mono (3-methylpentyl) ester and the like.

Examples of phosphoric acids in which R '''is an alkyl group and k is 2 include phosphoric acid dimethyl ester, phosphoric acid diethyl ester, phosphoric acid di-n-propyl ester, phosphoric acid diisopropyl ester, and phosphoric acid di-n-. Butyl ester,
Phosphoric acid diisobutyl ester, phosphoric acid disec-butyl ester, phosphoric acid ditert-butyl ester, phosphoric acid di-n-pentyl ester, phosphoric acid di (1-methylbutyl) ester, phosphoric acid di (2-methylbutyl) ester, phosphorus Acid di (3-methylbutyl) ester, phosphoric acid di (1,1-dimethylpropyl) ester, phosphoric acid di (2,2-dimethylpropyl) ester, phosphoric acid di (1,2-dimethylpropyl) ester, phosphoric acid The n
-Hexyl ester, di (2-methylpentyl) phosphate
Examples include esters and phosphoric acid di (3-methylpentyl) esters.

When these k are 1 or 2, among them, in terms of proton conductivity, phosphoric acid monomethyl ester, phosphoric acid monoethyl ester, phosphoric acid mono n-propyl ester, phosphoric acid monoisopropyl ester, phosphoric acid, etc. Dimethyl ester, phosphoric acid diethyl ester, phosphoric acid di-n-propyl ester, phosphoric acid diisopropyl ester or a mixture thereof is preferred, and phosphoric acid monoethyl ester, phosphoric acid mono-n-propyl ester, phosphoric acid monoisopropyl ester, phosphoric acid diethyl ester , Phosphoric acid di-n-propyl ester, phosphoric acid diisopropyl ester or a mixture thereof are more preferable, and phosphoric acid monoisopropyl ester, phosphoric acid diisopropyl ester or a mixture thereof are particularly preferable.

Examples of phosphoric acids in which R ″ ′ is an aryl group and k is 1 include phosphoric acid monophenyl ester, phosphoric acid monotolyl ester, phosphoric acid monoethylphenyl ester, phosphoric acid monoisopropylphenyl ester and phosphoric acid. Examples thereof include mononaphthyl ester, phosphoric acid monoanthryl ester, phosphoric acid monophenanthryl ester, phosphoric acid mononitrophenyl ester, phosphoric acid monochlorophenyl ester and phosphoric acid monobromophenyl ester.

Examples of phosphoric acids in which R ″ ′ is an aryl group and k is 2 include phosphoric acid diphenyl ester, phosphoric acid ditolyl ester, phosphoric acid di (ethylphenyl) ester, phosphoric acid di (isopropylphenyl) ester and phosphoric acid. Acid dinaphthyl ester, phosphoric acid dianthryl ester, phosphoric acid diphenanthryl ester, phosphoric acid di (nitrophenyl)
Examples include esters, phosphoric acid di (chlorophenyl) esters, phosphoric acid di (bromophenyl) esters, and the like. k
When is 0, (2) represents orthophosphoric acid.

The above-mentioned phosphoric acid (2) is usually used in an amount of 0.1 to 10 equivalents based on the phosphorus atom-equivalent mole number of the phosphorus polymer compound (1). Above all, it is preferable to use 2 equivalents or more, and in this case, high and stable proton conductivity is exhibited. More preferably, it is 2 to 5 equivalents.

When the polymer electrolyte composition of the present invention is used in a fuel cell, it is usually used in the form of a membrane. The method for obtaining a membrane by containing phosphoric acid in a phosphorus-based polymer compound is
A method of forming a film by adding phosphoric acid to a solution of a phosphorus-based polymer compound and then casting the solution to volatilize the solvent, for example, subjecting a polymer electrolyte film produced by the method described below to immersion in a solution of phosphoric acid The method is preferable, and the method is preferable because the treatment is simple. In the method of, after adding phosphoric acid to the solution of the phosphorus-based polymer compound, after casting film formation on a glass plate or the like, by removing the solvent,
A film in which phosphoric acid is contained in a phosphorus-based polymer compound can be prepared. The thickness of the film is not particularly limited, but is preferably 10 to 200 μm. It is preferably thicker than 10 μm in order to obtain practical strength of the film, and thinner than 200 μm in order to reduce membrane resistance, that is, improve power generation performance. The film thickness can be controlled by the solution concentration or the coating thickness on the substrate.

The solvent for the solution of the phosphorus-based polymer compound is not particularly limited as long as it can be dissolved and can be removed thereafter. For example, N, N-dimethylformamide, N, N- Aprotic polar solvents such as dimethylacetamide, N-methyl-2-pyrrolidone, dimethylsulfoxide, dichloromethane, chloroform,
Chlorinated solvents such as 1,2-dichloroethane, chlorobenzene and dichlorobenzene, alcohols such as methanol, ethanol and propanol, alkylenes such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether and propylene glycol monoethyl ether Examples thereof include glycol monoalkyl ether and water. These may be used alone, or may be used as a mixture of two or more kinds of solvents, if necessary. The concentration of the phosphorus-based polymer compound solution before the addition of phosphoric acids varies depending on the phosphorus-based polymer compound, solvent, and phosphoric acid used,
It is usually 2 to 50 parts by weight, preferably 5 to 30 parts by weight, relative to 100 parts by weight of the solvent. If the concentration is too low, the viscosity of the solution will be too low, making it difficult to control the film thickness, and if the concentration is too high, the viscosity will be too high and it will be difficult to form a uniform film.

In the method, the solvent for the phosphoric acid solution is not particularly limited as long as it does not dissolve the phosphorus-based polymer compound but can dissolve the phosphoric acid and can be removed thereafter. , Methanol, ethanol,
Volatile solvents such as n-hexane and tetrahydrofuran, water and the like are preferable because removal of the solvent is easy. In the method of, by changing the concentration of the phosphoric acid solution, the temperature of the solution, the immersion time in the phosphoric acid solution, or the solvent used,
The amount introduced into the membrane can be controlled. The concentration of the phosphoric acid solution is usually in the range of 5% by weight to 100% by weight, and 20% by weight to 100% by weight is preferable from the viewpoint of ensuring introduction that contributes to improvement of proton conductivity. The temperature during the dipping treatment is usually preferably 0 ° C to 100 ° C, and more preferably 20 ° C to 40 ° C from the viewpoint of preventing the solvent from volatilizing during the dipping treatment.

The polymer electrolyte composition membrane of the present invention may be combined with a porous support membrane, if necessary, from the viewpoint of the mechanical strength of the membrane. The porous support membrane to be used is not particularly limited, but examples of the material include polyethylene, polypropylene, polytetrafluoroethylene, and the like, and those having a porosity of 30% or more and a film thickness of 100 μm or less are preferably used. In addition, various known additives such as antioxidants can be added within a range that does not impair the object of the present invention.

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 substance as a current collector to both surfaces of the polymer electrolyte membrane. The catalyst is not particularly limited as long as it can activate the redox reaction with hydrogen or oxygen, and known catalysts can be used, but platinum fine particles are preferably used. The platinum fine particles are preferably used by being supported on a particulate or fibrous carbon such as activated carbon or graphite. Known materials can be used for the conductive substance as the current collector, but a porous carbon nonwoven fabric or carbon paper is preferable for efficiently transporting the raw material gas to the catalyst. For the method of joining platinum fine particles or carbon carrying platinum fine particles to a porous carbon nonwoven fabric or carbon paper, and the method of joining it to a polymer electrolyte film, see, for example, J. Electrochem. S
oc. : Electrochemical Scie
nce and Technology, 1988,
Known methods such as the methods described in 135 (9), 2209 can be used.

[0043]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

Production Example 1 [Aromatic polymer phosphonic acid (P1) represented by the general formula (1)] In a 500 ml flask equipped with a mechanical stirrer,
Alternate copolymer of the above structural formula (Made by Aldrich, molecular weight (polystyrene conversion): Mn = 3.0 × 10 ⁴ , Mw = 6.8 × 1
0 ⁴ ) 15.0 g (unit 47.5 derived from 4,4'-biphenol)
mmol), 35.0 g (197 mmol) of N-bromosuccinimide and 202 g of methylene chloride, and the mixture was stirred under a nitrogen atmosphere. When 99.6 g of concentrated sulfuric acid was added dropwise to this suspension under ice cooling over 75 minutes, a seaweed-like product was precipitated from the middle. After completion of the dropwise addition, the mixture was stirred for 1 hour and a half under ice cooling, then the reaction mixture was poured into ice, a small amount of sodium sulfite was added, and the mixture was stirred. After concentration under reduced pressure with an evaporator, the obtained aqueous slurry was filtered, washed repeatedly with water while introducing a neutralizing operation, and then dried under reduced pressure.

7 g of the brominated polymer obtained above (containing bromo group: 26.0 mol) was added to N, N-dimethylformamide.
Dissolved in 183g, 5.11g (39.4mmol) of nickel (II) chloride
And stirred under a nitrogen atmosphere. The mixture was heated to 7.71 g (46.4 g) of triethyl phosphite at an oil bath temperature of 130 ° C.
mmol) was added dropwise over 10 minutes. The temperature was raised to the reflux temperature over 20 minutes, and after 1 and a half hours, 2.66 g (16.0 mmol) of triethyl phosphite was added dropwise under reflux. After stirring for 2 hours under reflux, the reaction mixture was poured into ice water, filtered, washed with dilute hydrochloric acid, repeatedly washed with water, neutralized with a dilute aqueous sodium hydrogen carbonate solution, and finally washed with water. After drying under reduced pressure, 5.63 g of polymer diethyl phosphonate was obtained.

10.2 g of the polymer diethyl diethylphosphonate produced by the above method was added to 200 ml of a 21% hydrochloric acid aqueous solution, and the mixture was stirred for 8 hours under heating under reflux in a nitrogen atmosphere. The suspension was allowed to cool, filtered, washed with water, and then vacuum dried, and the obtained crude product was dissolved in N, N-dimethylformamide to give a solution.
Reprecipitation by adding a large excess of 5% hydrochloric acid, filtration,
After repeated washing with water, vacuum drying was performed to obtain 9.1 g of a polymer. As a result of the analysis, this polymer had a unit structure represented by the following structural formula (substitution of about 0.1 Br and about 1.3 phosphonic acid groups for each unit derived from 4,4′-biphenol). Turned out to have. Hereinafter, the polymer is abbreviated as (P1).

[0047] Elemental analysis results P: Analytical value 7.6% (calculated value 7.9%) Br: Analytical value 1.3% (calculated value 1.6%) (P atom is calculated to be 2.55 mmol per 1 g of polymer) Ion exchange capacity Elemental analysis result From this, it is calculated as 5.1 meq / g. Results of NMR analysis ¹ H-NMR (300MHz, DMSO-d6) 7.0-8.2 ppm (aromatic)

Measurement of Proton Conductivity Proton conductivity is measured in a constant humidity chamber at 120 ° C. under non-humidified conditions, SI1260 type high-performance impedance gain /
Face Analyzer (IMPEDANCE / GAIN-PHASE ANALYZE
R, solartoron) and 1287 type potentiostat (ELECTROCHEMICAL INTERFACE, solartoron) were used to measure by the AC impedance method. The unit is S /
cm.

Examples 1 to 4 [Production of Polymer Electrolyte Composition Membrane Composed of Polymer Electrolyte (P1) and Phosphoric Acid] As phosphoric acids, commercially available concentrated phosphoric acid (>
85 wt%, manufactured by Wako Pure Chemical Industries, Ltd.) was used. P1 and concentrated phosphoric acid,
DMAc (N, N-dimethylacetamide) was mixed well in the compounding amounts shown in Table 1 and spread on a glass plate. The solvent was dried under normal pressure to obtain the intended polymer electrolyte composition membrane. The appearance of each polymer film was uniform. Table 2 shows the evaluation results of changes in proton conductivity over time.

[0050]

[Table 1]

[0051]

[Table 2]

[0052]

EFFECT OF THE INVENTION The polymer electrolyte composition of the present invention contains a phosphorus-based polymer compound in which a phosphonic acid group or the like is directly bonded to an aromatic ring and phosphoric acid, so that a proton is produced even under a high temperature condition of 100 ° C. or higher. Shows conductivity. Further, a polymer electrolyte composition containing phosphoric acid in an amount of 2 equivalents or more based on the number of moles of phosphorus-based polymer compound converted to phosphorus atom shows more excellent and stable proton conductivity.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08L 71/10 C08L 71/10 5H026 H01B 1/06 H01B 1/06 A H01M 8/02 H01M 8/02 P 8/10 8/10 (72) Inventor Yasumasa Hidaka 6 Kitahara, Tsukuba-shi, Ibaraki Prefecture Sumitomo Chemical Co., Ltd. (72) Inventor Shigeru Sasaki 6 Kitahara, Tsukuba-shi, Ibaraki Sumitomo Chemical Co., Ltd. (72) Inventor Arihiro Yatsushiro 6 Kitahara, Tsukuba-shi, Ibaraki Sumitomo Chemical Co., Ltd. (72) Inventor Takumi Taniguchi 1st Toyota-cho, Toyota-shi, Aichi Toyota Automobile Co., Ltd. F-term (reference) 4F071 AA51 AA64 AA78 AC15 AE22 AH12 BA02 BB02 BC01 4J002 CH091 CN031 EW046 GQ00 4J005 AA24 BD07 4J030 BA10 BD10 BF13 BG06 5G301 CA30 CD01 5H026 AA06 CX05 EE18 HH05

Claims (10)

[Claims] 1. A polymer electrolyte composition comprising a phosphorus-based polymer compound represented by the general formula (1) and a phosphoric acid represented by the general formula (2). (Wherein, -Z- is -SO ₂ - represents or -CO-, x and y represent the 0.01 to 0.99, respectively, the sum of x and y is 1.-Ar- hetero element Represents a divalent aromatic group having 4 to 18 carbon atoms, which may include
Ar- may have a substituent. n represents the average number of substituents per unit structure of the polymer portion containing an aromatic group, and n represents a positive number of 8 or less. R and R ′ each independently represent a hydrogen atom or an alkyl group. ) O = P (R ′ ″ O) _k (OH) _3−k (2) (In the formula, R ′ ″ represents an alkyl group or an aryl group having 1 to 6 carbon atoms. _K represents 0 to 2) When k is 2,
Two R ″ ′ s may be the same or different. ) 2. The composition according to claim 1, wherein the phosphoric acid is contained in an amount of 2 equivalents or more based on the number of moles of the phosphorus-based polymer compound in terms of phosphorus atom. 3. The composition according to claim 1 or 2, wherein at least one of R and R'is a hydrogen atom. 4. The composition according to claim 1, wherein -Ar- is an optionally substituted phenylene group or an optionally substituted biphenyldiyl group. 5. The method according to claim 1, wherein k is 0.
4. The composition according to any one of 4 above. 6. A polymer electrolyte composition membrane comprising the composition according to any one of claims 1 to 5. 7. The polymer electrolyte composition membrane according to claim 6, which is a membrane obtained by casting a solution of the polymer electrolyte composition and volatilizing the solvent. 8. A polymer composite membrane comprising the polymer electrolyte composition according to claim 1 and a support in a composite form. 9. The polymer composite membrane according to claim 8, wherein the support is a porous support membrane made of an aliphatic polymer or a fluorine-containing polymer. 10. A fuel cell comprising the polymer electrolyte composition membrane or polymer composite membrane according to claim 6.