JP2005203316A - Proton conduction membrane and its forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a proton conduction membrane having proton conductivity substantially high even in a high temperature range of 100°C or higher and to provide its forming method. <P>SOLUTION: The proton conduction membrane contains (i) polyarylene having a sulfonic acid group including a repeating unit shown by a formula (A), and (ii) at least one low molecule acid selected from a low molecule phosphoric acid, a low molecule phosphonic acid, and a low molecule sulfonic acid. In a method for forming the proton conduction membrane, the membrane is formed by casting a solution composition including (i) the polyarylene and (ii) the low molecule acid on a substrate. In the formula, A is a divalent electron-attractive group, B is a divalent electron-donative group or a direct bond, and Ar is an aromatic group having a substituent expressed by -SO<SB>3</SB>H, where m is 0 to 10, n is 0 to 10, and k is 1 to 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a proton conductive membrane used as a solid polymer electrolyte membrane of a solid polymer fuel cell, for example, and a method for producing the same.

  A fuel cell basically comprises two catalyst electrodes and a solid electrolyte membrane sandwiched between the electrodes. Hydrogen as a fuel is ionized at one electrode, and this hydrogen ion diffuses through the solid electrolyte membrane and then combines with oxygen at the other electrode. At this time, if the two electrodes are connected by an external circuit, a current flows and power is supplied to the external circuit. Here, the solid electrolyte membrane has a function of diffusing hydrogen ions, physically separating hydrogen and oxygen of the fuel gas, and blocking the flow of electrons.

  As the solid electrolyte membrane, there are fluorine-based solid polymer electrolyte membranes typified by perfluorocarbon sulfonic acid membranes proposed by DuPont, Dow, Asahi Kasei, Asahi Glass and the like. Since this is excellent in chemical stability, it is used as a fuel cell used under severe conditions or as a solid polymer electrolyte membrane for water splitting.

  However, many solid polymer electrolyte membranes typified by fluorine-based solid polymer electrolyte membranes have a relatively low glass transition point and sulfonic acid groups are ion sites. In a temperature environment above the boiling point and below the saturated water vapor pressure, the electrolyte membrane is dried and the proton conductivity decreases. Therefore, the operating temperature of the fuel cell is limited to 100 ° C. or lower, preferably 80 ° C. or lower. For this reason, fluorine-based polymer electrolyte membranes are limited to special applications such as space or military polymer electrolyte fuel cells. To apply it, when reforming hydrogen gas using low-molecular hydrocarbons as raw fuel, it is necessary to cool the reformed gas or remove carbon monoxide in the reformed gas. It has become a factor that complicates.

  For this reason, when the fuel cell is operated at a high temperature, the electrode catalyst becomes highly active, the electrode overvoltage is reduced, and the poisoning of the electrode by carbon monoxide is reduced. ) Is desired to develop a solid polymer electrolyte membrane exhibiting sufficient proton conductivity.

  The present inventor has studied in view of such problems in the prior art, and as a result, the polyarylene having a sulfonic acid group is at least one selected from the group consisting of low molecular phosphoric acid, low molecular phosphonic acid and low molecular sulfonic acid. By doping with a low molecular weight acid, the ion exchange capacity can be easily controlled, and sufficient water can be retained for proton transport even at high temperatures (100 ° C. or higher), so that sufficient proton conductivity is exhibited. The inventors have found that a proton conductive membrane can be obtained and have completed the present invention.

In addition, as an example of a solid polymer electrolyte fuel cell in which a polymer membrane as an electrolyte contains a compound having a phosphate group, a perfluorocarbon sulfonic acid membrane is converted to a zirconium phosphate compound (Zr (O ₃ PCH ₂ SO There is one using a film immersed in an aqueous solution of ₃ H) ₂ ) (see Patent Document 1).
JP-A-6-103983

An object of the present invention is to provide a proton conductive membrane having sufficiently high proton conductivity even in a high temperature region of 100 ° C. or higher and a method for producing the same.

  According to the present invention, the following proton conducting membrane and a method for producing the same are provided to solve the above-described problems of the present invention.

(1)
(I) a polyarylene having a sulfonic acid group;
(Ii) A proton conducting membrane comprising at least one low molecular acid selected from the group consisting of low molecular phosphoric acid, low molecular phosphonic acid and low molecular sulfonic acid.

  (2) The polyarylene having the sulfonic acid group includes a repeating structural unit represented by the following general formula (A) and, if necessary, a repeating structural unit represented by the following general formula (B). The proton conducting membrane according to (1) above;

(In the formula, A represents a divalent electron-withdrawing group, B represents a divalent electron-donating group or a direct bond, Ar represents an aromatic group having a substituent represented by —SO ₃ H, m represents an integer of 0 to 10, n represents an integer of 0 to 10, and k represents an integer of 1 to 4.)

(In Formula (B), R ^{1 to} R ⁸ may be the same or different from each other, and are selected from the group consisting of a hydrogen atom, a fluorine atom, an alkyl group, a fluorine-substituted alkyl group, an allyl group, an aryl group, and a cyano group. And at least one kind of atom or group, W represents a divalent electron-withdrawing group or single bond, T represents a single bond or a divalent organic group, and p represents 0 or a positive integer.) .

  (3) The proton conductive membrane as described in (1) or (2) above, wherein the low molecular acid is at least one selected from the group consisting of low molecular phosphoric acid and low molecular sulfonic acid.

  (4) Said low molecular acid is contained in the ratio of 0.01-70 weight part with respect to 100 weight part of polyarylene which has the said sulfonic acid group, The said (1)-(3) characterized by the above-mentioned. The proton conductive membrane according to any one of the above.

(5)
(I) a polyarylene having a sulfonic acid group;
(Ii) at least one low molecular acid selected from the group consisting of low molecular phosphoric acid, low molecular phosphonic acid and low molecular sulfonic acid;
(Iii) A method for producing a proton conducting membrane, comprising producing a film by casting a solution composition containing a solvent on a substrate.

  In the proton conducting membrane according to the present invention, since the polyarylene having a sulfonic acid group contains a low molecular acid, the amount of water restrained in the membrane can be increased. In other words, in addition to the presence of fixed ionic groups in the membrane, water molecules and hydratable low-molecular acids are mixed in the membrane, so water molecules hydrate with low-molecular acids and more restraints. Water molecules are present. As a result, water molecules constrained by the fixed ionic groups in the membrane increase, and evaporation is suppressed unlike normal unconstrained free water. Therefore, it is possible to suppress a decrease in the moisture content of the membrane at a high temperature of 100 ° C. or higher, and the proton conductivity can be improved.

  According to the method for producing a proton conducting membrane according to the present invention, it is easy to control the ion exchange capacity. In particular, this method can easily achieve even a high ion exchange capacity, which is difficult with a commonly used copolymerization method.

  The proton conductive membrane of the present invention can be used for, for example, an electrolyte for a primary battery, an electrolyte for a secondary battery, a display element, various sensors, a signal transmission medium, a solid capacitor, an ion exchange membrane, and the like.

Hereinafter, the proton conducting membrane and the method for producing the same according to the present invention will be specifically described.
The proton conducting membrane according to the present invention is
(I) a polyarylene having a sulfonic acid group;
(Ii) at least one low molecular acid selected from the group consisting of low molecular phosphoric acid, low molecular phosphonic acid and low molecular sulfonic acid.

(Polyarylene having a sulfonic acid group)
First, the polyarylene having a sulfonic acid group used in the present invention will be specifically described.

  The polyarylene having a sulfonic acid group used in the present invention includes a repeating structural unit represented by the following general formula (A) and, if necessary, a repeating structural unit represented by the following general formula (B). .

In the formula (A), A represents a divalent electron-withdrawing group, specifically, —CO—, —SO ₂ —, —S.
O—, —CONH—, —COO—, — (CF ₂ ) ₁ — (wherein 1 is an integer of 1 to 10), —C (CF ₃ ) ₂ — and the like can be mentioned.
B represents a divalent electron-donating group or a direct bond, and specific examples of the electron-donating group include — (CH ₂
)-, -C (CH ₃ ) _2- , -O-, -S-, -CH = CH-, -C≡C- and

Etc.
The electron-withdrawing group is a Hammett substituent constant when the phenyl group is in the m-position.
In the case of 0.06 or more and p-position, it means a group having a value of 0.01 or more.
Ar represents an aromatic group having a substituent represented by —SO ₃ H, and specific examples of the aromatic group include a phenyl group, a naphthyl group, an anthracenyl group, and a phenanthyl group. Of these groups, a phenyl group and a naphthyl group are preferable.
m represents an integer of 0 to 10, preferably 0 to 2, n represents an integer of 0 to 10, preferably 0 to 2, and k represents an integer of 1 to 4.

In formula (B), R ^{1 to} R ⁸ may be the same as or different from each other, and are selected from the group consisting of a hydrogen atom, a fluorine atom, an alkyl group, a fluorine-substituted alkyl group, an allyl group, an aryl group, and a cyano group. At least one atom or group is shown.
Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, an amyl group, and a hexyl group, and a methyl group and an ethyl group are preferable.
Examples of the fluorine-substituted alkyl group include trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluorobutyl group, perfluoropentyl group, perfluorohexyl group, trifluoromethyl group, pentafluoroethyl group, and the like. Etc. are preferable.
Examples of allyl groups include propenyl groups,
Examples of the aryl group include a phenyl group and a pentafluorophenyl group.

W represents a single bond or a divalent electron-withdrawing group. Examples of the divalent electron withdrawing group include the same ones as described above.
T represents a single bond or a divalent organic group. Specific examples of the divalent organic group include an electron-withdrawing group and an electron-donating group, and examples of the electron-withdrawing group and the electron-donating group include those described above.

In the formula (B), p is 0 or a positive integer, and the upper limit is usually 100, preferably 10-80.
When the polyarylene having a sulfonic acid group includes a repeating structural unit represented by the general formula (A) and a repeating structural unit represented by the general formula (B), specifically, the following general formula (C ).

(In the formula (D), W, T, A, B, Ar, m, n, k, p and R ^{1 to} R ⁸ are respectively W, T, A in the general formulas (A) and (B). , B, Ar, m, n, k, p, and R ^{1 to} R ⁸ .
The polyarylene having a sulfonic acid group used in the present invention contains 0.5 to 100 mol%, preferably 10 to 99.999 mol% of the repeating structural unit represented by the formula (A). ) Is contained in a proportion of 99.5 to 0 mol%, preferably 90 to 0.001 mol%.

(Method for producing polyarylene having a sulfonic acid group)
The polyarylene having a sulfonic acid group can be a monomer having a sulfonic acid ester group that can be a structural unit represented by the general formula (A), and a structural unit represented by the general formula (B) as necessary. A polyarylene having a sulfonic acid ester group is produced by copolymerizing with an oligomer, and the polyarylene having a sulfonic acid ester group is hydrolyzed and synthesized by converting the sulfonic acid ester group into a sulfonic acid group. Can do.

  The polyarylene having a sulfonic acid group has a skeleton represented by the general formula (A) and a structural unit having no sulfonic acid group or sulfonic acid ester group, and if necessary, the general formula (B). It is also possible to synthesize a polyarylene composed of the structural unit in advance and sulfonate the polyarylene having no sulfonic acid ester group and no sulfonic acid group.

  In the case of synthesizing a polyarylene having a sulfonate group by copolymerizing a monomer that can be a structural unit of the general formula (A) and an oligomer that can be a structural unit of the general formula (B), if necessary. As the monomer that can be the structural unit of the general formula (A), for example, a sulfonate ester represented by the following general formula (D) (hereinafter also referred to as “monomer (D)”) is used.

In the formula (D), X represents a halogen atom other than fluorine (chlorine, bromine, iodine), —OSO ₂ Z (
Here, Z represents an alkyl group, a fluorine-substituted alkyl group or an aryl group. A, B, m, n and k have the same meanings as A, B, m, n and k in the general formula (A), respectively. R ^a represents a hydrocarbon group having 1 to 20 carbon atoms, preferably 4 to 20 carbon atoms, specifically, methyl group, ethyl group, n-propyl group, iso-propyl group, tert-butyl group, iso- Butyl group, n-butyl group, sec-butyl group, neopentyl group, cyclopentyl group, hexyl group, cyclohexyl group, cyclopentylmethyl group, cyclohexylmethyl group, adamantyl group, adamantanemethyl group, 2-ethylhexyl group, bicyclo [2.2 .1] heptyl group, bicyclo [2.2.1] heptylmethyl group, tetrahydrofurfuryl group, 2-methylbutyl group, 3,3-dimethyl-2,4-dioxolanemethyl group, cyclohexylmethyl group, adamantylmethyl group , Straight chain hydrocarbon groups such as bicyclo [2.2.1] heptylmethyl group, branched hydrocarbon groups, alicyclic carbon groups Examples thereof include a hydrogen group and a hydrocarbon group having a 5-membered heterocyclic ring. Among these, an n-butyl group, neopentyl group, tetrahydrofurfuryl group, cyclopentyl group, cyclohexyl group, cyclohexylmethyl group, adamantylmethyl group, and bicyclo [2.2.1] heptylmethyl group are preferable, and a neopentyl group is more preferable. .

Ar ′ represents an aromatic group having a sulfonate group represented by —SO ₃ R ^b , and specific examples of the aromatic group include a phenyl group, a naphthyl group, an anthracenyl group, and a phenanthyl group. Of these groups, a phenyl group and a naphthyl group are preferable.

The sulfonate group —SO ₃ R ^b is substituted with one or more aromatic groups, and when two or more sulfonate groups —SO ₃ R ^b are substituted, these sulfone groups The acid ester groups may be the same or different from each other.

Here, R ^b represents a hydrocarbon group having 1 to 20 carbon atoms, preferably 4 to 20 carbon atoms, and specific examples thereof include the hydrocarbon groups having 1 to 20 carbon atoms. Among these, an n-butyl group, neopentyl group, tetrahydrofurfuryl group, cyclopentyl group, cyclohexyl group, cyclohexylmethyl group, adamantylmethyl group, and bicyclo [2.2.1] heptylmethyl group are preferable, and a neopentyl group is more preferable. .

  Specific examples of the sulfonic acid ester represented by the above formula (D) include the following compounds.

Further, as the sulfonate ester represented by the general formula (D), a compound in which a chlorine atom is replaced with a bromine atom in the above compound, a compound in which —CO— is replaced with —SO ₂ — in the above compound, and chlorine in the above compound atom is replaced by a bromine atom, and -CO- is -SO ₂ - can also be mentioned such compounds replaced.

The R ^b group in the general formula (D) is derived from a primary alcohol, and the β carbon is a tertiary or quaternary carbon, which is excellent in stability during the polymerization process and produces sulfonic acid by deesterification. It is preferable in that it does not cause polymerization inhibition or cross-linking due to the above, and it is preferable that these ester groups are derived from primary alcohols and the β-position is quaternary carbon.

  Specific examples of the compound having the same skeleton as the sulfonic acid ester represented by the general formula (D) and having no sulfonic acid group or sulfonic acid ester group include the following compounds.

A compound in which a chlorine atom is replaced with a bromine atom in the above compound, a compound in which —CO— is replaced with —SO ₂ — in the above compound, a chlorine atom is replaced with a bromine atom in the above compound, and —CO— is replaced with —SO ₂ —. Examples include substituted compounds.

  As the oligomer that can be the structural unit of the general formula (B), for example, a compound represented by the following general formula (E) (hereinafter, also referred to as “oligomer (E)”) is used.

In the formula (E), R ^{1 to} R ⁸ , W, T and p are respectively R ^{1 to} R ⁸ in the general formula (B),
Synonymous with W, T and p.
R ′ and R ″ may be the same or different from each other, and are represented by a halogen atom excluding a fluorine atom or —OSO ₂ Z (wherein Z represents an alkyl group, a fluorine-substituted alkyl group or an aryl group). Represents a group. Examples of the alkyl group represented by Z include a methyl group and an ethyl group, examples of the fluorine-substituted alkyl group include a trifluoromethyl group, and examples of the aryl group include a phenyl group and a p-tolyl group.

Specifically, as the compound represented by the general formula (E), when p = 0, for example, 4,4′-dichlorobenzophenone, 4,4′-dichlorobenzanilide, bis (chlorophenyl) difluoromethane, 2, 2-bis (4-chlorophenyl) hexafluoropropane, 4-chlorobenzoic acid-4-chlorophenyl, bis (4-chlorophenyl) sulfoxide, bis (4-chlorophenyl) sulfone, 2,6-dichlorobenzonitrile, 9,9- Bis (4-hydroxyphenyl) fluorene is mentioned. In these compounds, compounds in which a chlorine atom is replaced with a bromine atom or an iodine atom, and compounds in which at least one of halogen atoms substituted in the 4-position in these compounds are substituted in the 3-position are exemplified.

When p = 1, the specific compound represented by the general formula (E) is, for example, 4,
4′-bis (4-chlorobenzoyl) diphenyl ether, 4,4′-bis (4-chlorobenzoylamino) diphenyl ether, 4,4′-bis (4-chlorophenylsulfonyl) diphenyl ether, 4,4′-bis (4- Chlorophenyl) diphenyl ether dicarboxylate, 4,4′-bis [(4-chlorophenyl) -1,1,1,3,3,3-hexafluoropropyl] diphenyl ether, 4,4′-bis [(4-chlorophenyl) Tetrafluoroethyl] diphenyl ether, compounds in which the chlorine atom is replaced with a bromine atom or iodine atom in these compounds, compounds in which the halogen atom substituted in the 4-position in these compounds is substituted in the 3-position, and further in these compounds, diphenyl ether At least one of the groups substituted in the 4-position is in the 3-position And the like.

Further, the compound represented by the general formula (E) is 2,2-bis [4- {4- (4-
Chlorobenzoyl) phenoxy} phenyl] -1,1,1,3,3,3-hexafluoropropane, bis [4- {4- (4-chlorobenzoyl) phenoxy} phenyl] sulfone, and the following formula Compounds.

The compound represented by the general formula (E) can be synthesized, for example, by the method shown below.
First, in order to convert the bisphenol linked with an electron-withdrawing group into the corresponding alkali metal salt of bisphenol, dielectrics such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, sulfolane, diphenylsulfone, dimethylsulfoxide, etc. Add an alkali metal such as lithium, sodium or potassium, an alkali metal hydride, an alkali metal hydroxide, an alkali metal carbonate or the like in a polar solvent having a high rate.

Usually, the alkali metal is reacted in excess with respect to the hydroxyl group of phenol, and usually 1.1 to 2 times equivalent is used. Preferably, 1.2 to 1.5 times equivalent is used. In this case, fluorine, chlorine, etc. activated with an electron-withdrawing group in the presence of azeotropic solvent such as benzene, toluene, xylene, hexane, cyclohexane, octane, chlorobenzene, dioxane, tetrahydrofuran, anisole, phenetole, etc. Aromatic halogen-substituted aromatic dihalide compounds such as 4,4′-difluorobenzophenone, 4,4′-dichlorobenzophenone, 4,4′-chlorofluorobenzophenone, bis (4-chlorophenyl) sulfone, bis (4 -Fluorophenyl) sulfone, 4-fluorophenyl-4'-chlorophenylsulfone, bis (3-nitro-4-chlorophenyl) sulfone, 2,6-dichlorobenzonitrile, 2,6-difluorobenzonitrile, hexafluorobenzene, deca Fluorobiphenyl, , 5-difluorobenzophenone, 1,3-bis (4-chlorobenzoyl) reacting benzene. In terms of reactivity, a fluorine compound is preferable, but in consideration of the following aromatic coupling reaction, it is necessary to assemble an aromatic nucleophilic substitution reaction so that the terminal is a chlorine atom. The active aromatic dihalide is used in an amount of 2 to 4 times mol, preferably 2.2 to 2.8 times mol, of bisphenol. Prior to the aromatic nucleophilic substitution reaction, an alkali metal salt of bisphenol may be used. The reaction temperature is 60 ° C to 300 ° C, preferably 80 ° C to 250 ° C. The reaction time ranges from 15 minutes to 100 hours, preferably from 1 hour to 24 hours. The most preferable method is to use a chlorofluoro compound having one halogen atom having a different reactivity as the active aromatic dihalide represented by the following formula, and a nucleophilic substitution reaction with phenoxide occurs preferentially by the fluorine atom. It is convenient to obtain the desired activated terminal chloro form.

(Wherein, W is as defined for general formula (E).)
In addition, as a method for synthesizing the compound represented by the general formula (E), a nucleophilic substitution reaction and an electrophilic substitution reaction are combined as described in JP-A-2-159, and the target electron-withdrawing group is synthesized. There is a method for synthesizing a flexible compound comprising an electron donating group.

Specifically, an aromatic bishalide activated with an electron-withdrawing group, for example, bis (4-chlorophenyl) sulfone is subjected to a nucleophilic substitution reaction with phenol to obtain a bisphenoxy substitution product. Subsequently, the compound of interest is obtained by Friedel-Craft reaction of this bisphenoxy-substituted product with, for example, 4-chlorobenzoic acid chloride. As the aromatic bishalide activated with the electron-withdrawing group used here, the compounds exemplified above can be applied. Although phenol may be substituted, an unsubstituted compound is preferable from the viewpoint of heat resistance and flexibility. In addition, it is preferable to use an alkali metal salt for the substitution reaction of phenol, and as the alkali metal compound, the compounds exemplified above can be used. The amount used is 1.2 to 2 moles per mole of phenol. In the reaction, the polar solvent described above or an azeotropic solvent with water can be used. In the Friedel-Crafts reaction, a bisphenoxy compound is reacted with chlorobenzoic acid chloride as an acylating agent in the presence of an activator of a Lewis acid Friedel-Crafts reaction such as aluminum chloride, boron trifluoride or zinc chloride. Chlorobenzoic acid chloride is used in an amount of 2 to 4 times mol, preferably 2.2 to 3 times mol, of the bisphenoxy compound. The Friedel-Craft activator is used in an amount of 1.1 to 2 times equivalent to 1 mol of an active halide compound such as chlorobenzoic acid as an acylating agent. The reaction time ranges from 15 minutes to 10 hours, and the reaction temperature ranges from -20 ° C to 80 ° C. As the solvent used, chlorobenzene, nitrobenzene and the like which are inert to Friedel-Crafts reaction can be used.

Further, in the general formula (E), the compound in which p is 2 or more is, for example, a bisphenol that is a source of etheric oxygen that is the electron donating group T in the general formula (E) and an electron withdrawing group W. A compound in combination with at least one group selected from> C═O, —SO ₂ — and> C (CF ₃ ) ₂ , specifically 2,2-bis (4-hydroxyphenyl) -1 1,1,3,3,3-hexafluoropropane, alkali metal salts of bisphenols such as 2,2-bis (4-hydroxyphenyl) ketone, 2,2-bis (4-hydroxyphenyl) sulfone, and excess Substitution reaction with an active aromatic halogen compound such as 4,4-dichlorobenzophenone and bis (4-chlorophenyl) sulfone is carried out with N-methyl-2-pyrrolidone, N, N-
It is obtained by sequentially polymerizing the monomers in the presence of a polar solvent such as dimethylacetamide or sulfolane.

  Examples of such compounds include compounds represented by the following formulas.

  In the above, p is 0 or a positive integer, and the upper limit is usually 100, preferably 10-80.

  The polyarylene having a sulfonate group represented by the general formula (C) is synthesized by reacting the monomer (D) and the oligomer (E) in the presence of a catalyst. Is a catalyst system containing a transition metal compound. This catalyst system includes (1) a compound that becomes a transition metal salt and a ligand (hereinafter referred to as “ligand component”) or a ligand. In addition, a transition metal complex (including a copper salt) and (2) a reducing agent are essential components, and a “salt” may be added to increase the polymerization rate.

  Here, as the transition metal salt, nickel compounds such as nickel chloride, nickel bromide, nickel iodide and nickel acetylacetonate; palladium compounds such as palladium chloride, palladium bromide and palladium iodide; iron chloride and iron bromide And iron compounds such as iron iodide; cobalt compounds such as cobalt chloride, cobalt bromide, and cobalt iodide. Of these, nickel chloride, nickel bromide and the like are particularly preferable.

As the ligand component, triphenylphosphine, 2,2′-bipyridine, 1,5-
Examples include cyclooctadiene and 1,3-bis (diphenylphosphino) propane. Of these, triphenylphosphine and 2,2′-bipyridine are preferred. The compound which is the said ligand component can be used individually by 1 type or in combination of 2 or more types.

Furthermore, as the transition metal complex in which the ligand is coordinated, for example, nickel chloride bis (triphenylphosphine), nickel bromide bis (triphenylphosphine), nickel iodide bis (triphenylphosphine), nickel nitrate bis (Triphenylphosphine), nickel chloride (2,2'-bipyridine), nickel bromide (2,2'-bipyridine), nickel iodide (2,2'-bipyridine), nickel nitrate (2,2'-bipyridine) ), Bis (1,5-cyclooctadiene) nickel, tetrakis (triphenylphosphine) nickel, tetrakis (triphenylphosphite) nickel, tetrakis (triphenylphosphine) palladium and the like. Of these, nickel chloride bis (triphenylphosphine) and nickel chloride (2,2′-bipyridine) are preferred.

  Examples of the reducing agent that can be used in the catalyst system include iron, zinc, manganese, aluminum, magnesium, sodium, calcium, and the like. Of these, zinc, magnesium and manganese are preferred. These reducing agents can be used after being more activated by bringing them into contact with an acid such as an organic acid.

  Examples of the “salt” that can be used in the above catalyst system include sodium compounds such as sodium fluoride, sodium chloride, sodium bromide, sodium iodide, sodium sulfate, potassium fluoride, potassium chloride, potassium bromide, Examples include potassium compounds such as potassium iodide and potassium sulfate; ammonium compounds such as tetraethylammonium fluoride, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide, and tetraethylammonium sulfate. Of these, sodium bromide, sodium iodide, potassium bromide, tetraethylammonium bromide, and tetraethylammonium iodide are preferred.

  The proportion of each component used is usually from 0.0001 to 10 mol, based on 1 mol of the total amount of the above-mentioned monomers (the total amount of monomers (D) + oligomer (E), hereinafter the same)) of the transition metal salt or transition metal complex. Preferably it is 0.01-0.5 mol. When the amount is less than 0.0001 mol, the polymerization reaction may not proceed sufficiently. On the other hand, when the amount exceeds 10 mol, the molecular weight may decrease.

  When a transition metal salt and a ligand component are used in the catalyst system, the ratio of the ligand component used is usually 0.1 to 100 mol, preferably 1 to 10 mol, per 1 mol of the transition metal salt. is there. When the amount is less than 0.1 mol, the catalytic activity may be insufficient. On the other hand, when the amount exceeds 100 mol, the molecular weight may decrease.

  Moreover, the usage-amount of a reducing agent is 0.1-100 mol normally with respect to the total of 1 mol of the said monomer, Preferably it is 1-10 mol. If the amount is less than 0.1 mol, polymerization may not proceed sufficiently. If the amount exceeds 100 mol, purification of the resulting polymer may be difficult.

  Furthermore, when using "salt", the usage-ratio is 0.001-100 mol normally with respect to the total of 1 mol of the said monomer, Preferably it is 0.01-1 mol. If it is less than 0.001 mol, the effect of increasing the polymerization rate may be insufficient, and if it exceeds 100 mol, purification of the resulting polymer may be difficult.

Examples of the polymerization solvent that can be used when the monomer (D) and the oligomer (E) are reacted include tetrahydrofuran, cyclohexanone, dimethyl sulfoxide, N,
N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, γ-butyrolactone, N, N′-dimethylimidazolidinone and the like can be mentioned. Of these, tetrahydrofuran, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, and N, N′-dimethylimidazolidinone are preferable. These polymerization solvents are preferably used after sufficiently dried.

The total concentration of the monomers in the polymerization solvent is usually 1 to 90% by weight, preferably 5 to 40% by weight.
Moreover, the superposition | polymerization temperature at the time of superposing | polymerizing is 0-200 degreeC normally, Preferably it is 50-120 degreeC. The polymerization time is usually 0.5 to 100 hours, preferably 1 to 40 hours.
The polyarylene having a sulfonic acid ester group obtained using the monomer (D) can be converted into a polyarylene having a sulfonic acid group by hydrolyzing the sulfonic acid ester group and converting it to a sulfonic acid group. .

Hydrolysis is
(1) A method in which polyarylene having the sulfonic acid ester group is added to an excess amount of water or alcohol containing a small amount of hydrochloric acid and stirred for 5 minutes or longer. (2) The sulfonic acid ester group is contained in trifluoroacetic acid. Method of reacting polyarylene for about 5 to 10 hours at a temperature of about 80 to 120 ° C. (3) 1 to 3 mol per mol of sulfonic acid ester group (—SO ₃ R) in polyarylene having a sulfonic acid ester group Examples include a method of reacting the polyarylene in a solution containing double moles of lithium bromide, such as N-methylpyrrolidone, at a temperature of about 80 to 150 ° C. for about 3 to 10 hours, and then adding hydrochloric acid. Can do.

  The polyarylene having a sulfonic acid group includes a monomer having a skeleton similar to that of the sulfonic acid ester represented by the general formula (D) and an oligomer represented by the general formula (E). When a polyarylene system having no sulfonic acid group is synthesized in advance by copolymerization and synthesized by sulfonating the polyarylene having no sulfonic acid group, the sulfonic acid group is obtained by a method according to the above synthesis method. After producing a polyarylene having no sulfonic acid, a polyarylene having a sulfonic acid group can be obtained by introducing a sulfonic acid group into the polyarylene having no sulfonic acid group using a sulfonating agent.

  The sulfonation of polyarylene having no sulfonic acid group is carried out by introducing a sulfonic acid group into the polyarylene having no sulfonic acid group by a conventional method using a sulfonating agent in the absence of a solvent or in the presence of a solvent. Can be obtained.

  As a method for introducing a sulfonic acid group, for example, the polyarylene having no sulfonic acid group is known by using a known sulfonating agent such as sulfuric anhydride, fuming sulfuric acid, chlorosulfonic acid, sulfuric acid, sodium hydrogen sulfite and the like. [Polymer Preprints, Japan, Vol. 42, No. 3, p. 730 (1993); Polymer Preprints, Japan, Vol. 43, No. 3, p. 736 (1994); Polymer Preprints, Japan, Vol. 42, No. 7, p. 2490-2492 (1993)].

That is, as the reaction conditions for the sulfonation, the polyarylene having no sulfonic acid group is reacted with the sulfonating agent in the absence of a solvent or in the presence of a solvent. Examples of the solvent include hydrocarbon solvents such as n-hexane, ether solvents such as tetrahydrofuran and dioxane, aprotic polar solvents such as dimethylacetamide, dimethylformamide, and dimethylsulfoxide, tetrachloroethane, dichloroethane, chloroform, and chloride. And halogenated hydrocarbons such as methylene. The reaction temperature is not particularly limited, but is usually −50 to 200 ° C., preferably −10 to 100 ° C. Moreover, reaction time is 0.5 to 1,000 hours normally, Preferably it is 1 to 200 hours.

  In the polyarylene having a sulfonic acid group produced by the method as described above, the amount of the sulfonic acid group is usually 0.3 to 5 meq / g, preferably 0.5 to 3 meq / g, more preferably 0.8 to 2.8 meq / g. If it is less than 0.3 meq / g, the proton conductivity is low and not practical. On the other hand, if it exceeds 5 meq / g, the water resistance may be significantly lowered, which is not preferable.

  The amount of the sulfonic acid group can be adjusted, for example, by changing the type, usage ratio, and combination of the monomer (D) and the oligomer (E).

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

  The polyarylene having a sulfonic acid group may contain an anti-aging agent, preferably a hindered phenol compound having a molecular weight of 500 or more. By containing the anti-aging agent, the durability as an electrolyte is further increased. Can be improved.

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

  In the present invention, the hindered phenol compound is preferably used in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the polyarylene having a sulfonic acid group.

(Low molecular acid)
Examples of the low molecular acid used in the present invention include low molecular phosphoric acid, low molecular phosphonic acid, and low molecular sulfonic acid. These low molecular acids can be used singly or in combination of two or more.

(Low phosphoric acid)
The low molecular phosphoric acid is not particularly limited as long as it is a low molecular compound having a phosphate group. For example, H ₃ PO ₂ represented by H ₃ PO ₄ , H ₃ PO ₃ , H ₄ P ₂ O ₅ , HPO ₂ , H ₄ P ₂ O ₆ ,
Phosphoric acids such as H ₄ P ₂ O ₇ , HPO ₃ , H ₄ P ₃ O ₁₀ , H ₃ PO ₅ , H ₄ P ₂ O ₈ ;
Zr (O ₃ PCH) ₂ , Zr (O ₃ PCH) ₂ .H ₂ O, Zr (O ₃ PCH ₂ COOH) ₂ , Zr (O ₃ PC ₂ H ₄ COOH) ₂ , Zr (O ₃ PCH ₂ SO ₃ H) Zirconium phosphate compounds such as ₂ ;
Alkylphosphoric acid such as methylphosphoric acid, ethylphosphoric acid, 2-ethylhexyl) phosphoric acid, n-butylphosphoric acid, phenylphosphoric acid, o-toluylphosphoric acid, p-toluylphosphoric acid, o-ethylphenylphosphoric acid, p-ethylphenylphosphoric acid Alkyl substituted phenyl phosphates such as p-isopropylphenyl phosphate;
halogen-substituted phenyl phosphates such as o-fluorophenyl phosphate, o-chlorophenyl phosphate, p-chlorophenyl phosphate, p-bromophenyl phosphate;
nitrophenyl phosphate such as m-nitrophenyl phosphate;
Dialkylphosphoric acids such as dimethylphosphoric acid, diethylphosphoric acid, di (2-ethylhexyl) phosphoric acid, di (n-butyl) phosphoric acid;
Diphenylphosphoric acid, di (o-toluyl) phosphoric acid, di (p-toluyl) phosphoric acid, di (o-ethylphenyl) phosphoric acid, di (p-ethylphenyl) phosphoric acid, di (p-isopropylphenyl) phosphorus Di (alkyl-substituted phenyl) phosphoric acids such as acids;
Di (halogen-substituted phenyl) phosphoric acid such as di (o-chlorophenyl) phosphoric acid, di (p-chlorophenyl) phosphoric acid, di (p-bromophenyl) phosphoric acid;
Di (nitrophenyl) phosphoric acid such as di (m-nitrophenyl) phosphoric acid;
And derivatives thereof.

(Low molecular phosphonic acid)
The low-molecular phosphonic acid is not particularly limited as long as it is a compound having a phosphonic acid group.
Alkyl-substituted phenylphosphonic acids such as phenylphosphonic acid, o-toluylphosphonic acid, p-toluylphosphonic acid, o-ethylphenylphosphonic acid, p-ethylphenylphosphonic acid, p-isopropylphenylphosphonic acid;
halogen-substituted phenylphosphonic acids such as o-chlorophenylphosphonic acid, p-chlorophenylphosphonic acid, p-bromophenylphosphonic acid;
Dialkylphosphonic acids such as dimethylphosphonic acid, diethylphosphonic acid, di (2-ethylhexyl) phosphonic acid, di (n-butyl) phosphonic acid;
di (nitrophenyl) phosphonic acid such as m-nitrophenylphosphonic acid;
Di (o-toluyl) phosphonic acid, di (p-toluyl) phosphonic acid, di (o-ethylphenyl) phosphonic acid, di (p-ethylphenyl) phosphonic acid, di (p-isopropylphenyl) phosphonic acid and the like (Alkyl-substituted phenyl) phosphonic acid;
Di (halogen-substituted phenyl) phosphonic acids such as di (o-chlorophenyl) phosphonic acid, di (p-chlorophenyl) phosphonic acid, di (p-bromophenyl) phosphonic acid;
Di (nitrophenyl) phosphonic acid such as di (m-nitrophenyl) phosphonic acid;
And derivatives thereof.

(Low molecular sulfonic acid)
The low-molecular sulfonic acid is not particularly limited as long as it is a compound having a sulfonic acid group. For example, sulfuric acid, 2- [4- (2-hydroxyethyl) -1-perazinyl] ethanesulfonic acid, 2-hydroxy-3 -[4- (2-hydroxyethyl) -1-piperazinyl] propanesulfonic acid, 3- [4- (2-hydroxyethyl) -1-piperazinyl] propanesulfonic acid, vinylsulfonic acid, 2-acrylamido-2-methyl Propanesulfonic acid, methylsulfonic acid, ethylsulfonic acid, 2-ethylhexylsulfonic acid, n-butylsulfonic acid, trifluoromethanesulfonic acid, aminomethanesulfonic acid, hydroxymethanesulfonic acid, 1-hydroxyethane-1-sulfonic acid, 1 1,1-ethanedisulfonic acid, 1,1-dimethyl-1-ethanesulfone , Iodo methanesulfonic _{acid, CFCl 2 SO 3 H, CF} 2
ClSO ₃ H, phenylsulfonic acid, o-toluylsulfonic acid, p-toluylsulfonic acid, o-ethylphenylsulfonic acid, p-ethylphenylsulfonic acid, p-isopropylphenylsulfonic acid, o-chlorophenylsulfonic acid, p-chlorophenyl Sulfonic acid, p-bromophenylsulfonic acid, p-toluenesulfonic acid, 2-aminophenol-4-sulfonic acid, p-phenolsulfonic acid, 3,4-diaminophenylsulfonic acid, 2-aminophenylsulfonic acid, hydroquinonesulfone Acid, mesitylene-2-sulfonic acid, 4-amino-phenol-3-sulfonic acid, 2,5-dichloro-phenylsulfonic acid, 1,3-phenylenediamino-4-sulfonic acid, o-cresol-5-sulfonic acid O-Dichlorophenylsulfonic acid, o-pheno Rusuruhon _{acid, p-HC 6 F 4 SO} 3 H, pentafluorophenyl acid and derivatives thereof.

  The low molecular acid includes low molecular phosphoric acid in which the hydrogen atom of phosphoric acid is substituted with a functional group having a phenyl group, low molecular phosphonic acid in which the hydrogen atom of phosphonic acid is substituted with a functional group having a phenyl group, and hydrogen in sulfuric acid. A low molecular sulfonic acid in which an atom is substituted with a functional group having a phenyl group is preferable.

When a rigid part such as a phenyl group is present in the molecule, the hydrophobicity increases, the outflow into water or methanol is suppressed, and the low molecular acid once adsorbed inside the polymer electrolyte membrane flows in the microenvironment. Even when a force for reverse diffusion from the inside of the membrane to the outside of the membrane due to the generation of a phase or the like, the low molecular acid is preferred because it tends to be difficult to be removed outside the membrane while changing its shape flexibly due to the influence of the rigid portion.
The low molecular acid is more preferably low molecular phosphoric acid or low molecular sulfonic acid.

(Proton conductive membrane production method)
The method for producing the proton conductive membrane according to the present invention as described above is not particularly limited, and examples thereof include a solution blend method, a dipping method, and an interfacial solidification method, and a solution blend method is preferable. The solution blend method is preferably used because the ion exchange capacity of the proton conducting membrane can be easily controlled by the addition ratio of the low molecular acid.

  In the solution blending method, a low molecular acid and a polyarylene having a sulfonic acid group as described above are blended in a solvent in which the polyarylene has a solubility, and a uniform solution (hereinafter also referred to as “solution composition”) is prepared. In this method, the film is formed.

Examples of the solvent used in the solution blend method include methanol, ethanol, 1-propanol, 2-propanol, n-butyl alcohol, 2-methyl-1-propanol, 1-pentanol, 2-pentanol, and 3-pen. Butanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 2-methyl-2-butanol, 3-methyl-2-butanol, 2,2-dimethyl 1-propanol, cyclohexanol, dicyclohexanol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 4-methyl-2-pentanol, 2-ethyl-1-butanol, 1-methylcyclohexanol, 2-methylcyclohexanol , 3-methylcyclohexanol, 4-methylcyclohexanol, 1-octano , 2-octanol, 2-ethyl-1-hexanol, ethylene glycol, propylene glycol, 1,3-butanediol, glycerol, m-cresol, diethylene glycol, dipropylene glycol, ethyl lactate, n-butyl lactate, diacetone Alcohol, dioxane, butyl ether, phenyl ether, isopentyl ether, dimethoxyethane, diethoxyethane, bis (2-methoxyethyl) ether, bis (2-ethoxyethyl) ether, cineol, benzylethylether, furan, tetrahydrofuran, anisole, Phenetol, acetal, acetone, methyl ethyl ketone, 2-pentanone, 3-pentanone, cyclopentanone, cyclohexanone, 2-hexanone, 4-methyl-2-pe Ntanone, 2-heptanone, 2,4-dimethyl-3-pentanone, 2-octanone, acetophenone, mesityl oxide, benzaldehyde, ethyl acetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate, isoamyl acetate, pentyl acetate , Isopentyl acetate, 3-methoxybutyl acetate, methyl butyrate, ethyl butyrate, methyl lactate, ethyl lactate, butyl lactate, γ-butyrolactone, 2-methoxyethanol, 2-ethoxyethanol, 2- (methoxymethoxy) ethanol, 2- Isopropoxyethanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, dimethyldiethylene glycol, dimethyl sulfoxide, dimethyl sulfone, diethyl sulfide, acetonitrile, butyronitrile, nitromethane, Toroetan, 2-nitropropane, nitrobenzene, benzene, toluene, xylene, hexane, cyclohexane, -thieno acetate, dimethylformamide, N- methyl-2-pyrrolidone, dimethyl sulfoxide, tetramethylurea, 1,3-dimethyl-2
-Imidazolidinone and the like.

Solvents used in the solution blending method include —O—, —OH, —CO—, —SO ₂ —, —
An organic solvent having at least one group selected from the group consisting of SO ₃ —, —CN and —CO ₂ — is preferable, and a water-soluble aprotic organic solvent is more preferable. These solvents may be used in combination of two or more, and one or more of them are —O—, —OH, —CO—, —SO ₂ —, —SO ₃ —, —CN and —CO. An organic solvent having at least one group selected from the group consisting of _2- is preferred, and at least one kind is preferably a water-soluble aprotic organic solvent.

  Moreover, it is preferable that the addition ratio of the said low molecular acid is 0.01-70 weight part with respect to 100 weight part of polyarylenes which have the said sulfonic acid group, More preferably, it is 1-50 weight part. If it is less than this range, the effect of improving proton conductivity is low. On the other hand, if it exceeds this range, it may be removed during fuel cell operation.

  The solution composition is prepared, for example, by mixing the above-mentioned components at a predetermined ratio and mixing them using a conventionally known method, for example, a high-share mixer such as a homogenizer, a disperser, a paint conditioner, or a ball mill. can do.

  In order to produce a film using the above-mentioned solution composition, a method of producing a film by, for example, a casting method in which the film is cast on a substrate by casting and then formed on the film can be mentioned. , Polyethylene terephthalate (PET) film and the like, but not limited to this, any material may be used as long as it is a substrate used in a normal solution casting method, for example, plastic or metal. It is not done.

  The polymer concentration of the solution composition at this time is usually 5 to 40% by weight, preferably 7 to 25% by weight, although it depends on the molecular weight of the polyarylene having sulfonic acid. If it is less than 5% by weight, it is difficult to form a thick film, and pinholes are easily generated. On the other hand, if it exceeds 40% by weight, the solution viscosity is so high that it is difficult to form a film, and surface smoothness may be lacking.

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

After film formation by the above casting method, 3 at 30 to 160 ° C., preferably 50 to 150 ° C.
A film can be obtained by drying for -180 minutes, preferably 5-120 minutes. The dry film thickness is usually 10 to 100 μm, preferably 20 to 80 μm.

  The proton conducting membrane according to the present invention can also be produced by a method (immersion method) in which a film made of polyarylene having a sulfonic acid group is immersed in a low molecular acid solution. In the dipping method, for example, a film is produced in the same manner as described above except that a low molecular acid is not used, and then the obtained film is immersed in a solution in which a low molecular acid is dissolved at room temperature for 5 to 72 hours. Dry at 30 to 160 ° C, preferably 50 to 150 ° C. The content ratio of the low molecular acid can be calculated from the weight increase amount of the film before and after the immersion. The solvent that dissolves the low molecular acid is preferably a solvent that does not dissolve the polyarylene film having a sulfonic acid group, and the concentration of the low molecular acid solution is preferably 10 to 95% by weight. When the concentration of the low molecular acid solution is less than the above range, the content ratio of the low molecular acid is low, and the proton conductivity of the resulting proton conductive membrane may be low. On the other hand, when the above range is exceeded, the polyarylene film having a sulfonic acid group may be dissolved in the low molecular acid solution.

[Example]
EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples.
In the examples, the sulfonic acid equivalent, molecular weight, and proton conductivity were determined as follows.

1. Sulfonic acid equivalent Wash the resulting polyarylene having sulfonic acid groups with water until it becomes neutral, thoroughly wash with water except for free remaining acid, dry, weigh a predetermined amount, and THF / Phenolphthalein dissolved in a mixed solvent of water was used as an indicator, titration was performed using a standard solution of NaOH, and the sulfonic acid equivalent was determined from the neutralization point.

2. Measurement of Molecular Weight The weight average molecular weight of polyarylene having no sulfonic acid group was determined by GPC using tetrahydrofuran (THF) as a solvent and the molecular weight in terms of polystyrene. The molecular weight of the polyarylene having a sulfonic acid group was determined by GPC using N-methyl-2-pyrrolidone (NMP) to which lithium bromide and phosphoric acid were added as a solvent as an eluent.

3. Measurement of proton conductivity AC resistance was measured by pressing a platinum wire (f = 0.5 mm) against the surface of a 5 mm wide strip-shaped proton conducting membrane sample, holding the sample in a constant temperature and humidity device, and between the platinum wires It was obtained from AC impedance measurement. That is, the impedance at an alternating current of 10 kHz was measured in an environment of 100 ° C., 120 ° C., 150 ° C. and saturated water vapor pressure. A chemical impedance measurement system manufactured by NF Circuit Design Block Co., Ltd. was used as the resistance measurement device, and JW241 manufactured by Yamato Scientific Co., Ltd. was used as the constant temperature and humidity device. Five platinum wires were pressed at intervals of 5 mm, the distance between the wires was changed to 5 to 20 mm, and the AC resistance was measured. The specific resistance of the membrane was calculated from the distance between the lines and the resistance gradient, the alternating current impedance was calculated from the reciprocal of the specific resistance, and the proton conductivity was calculated from this impedance.

Specific resistance R (Ω · cm) = 0.5 (cm) × film thickness (cm) × resistance-to-resistance gradient (Ω / cm)
[Synthesis Example 1]
(Preparation of oligomer)
2,2-bis (4-hydroxyphenyl) -1,1,1,3 was added to a 1 L three-necked flask equipped with a stirrer, thermometer, cooling tube, Dean-Stark tube, and three-way cock for introducing nitrogen. , 3,3-hexafluoropropane (bisphenol AF) 67.3 g (0.20 mol), 4,4′-dichlorobenzophenone (4,4′-DCBP) 60.3 g (0.24 mol), potassium carbonate 71 .9 g (0.52 mol), N, N-dimethylacetamide (DMAc) 300 mL, and toluene 150 mL were taken and heated in an oil bath under a nitrogen atmosphere and reacted at 130 ° C. with stirring. When water produced by the reaction was azeotroped with toluene and reacted while being removed from the system with a Dean-Stark tube, almost no water was produced in about 3 hours. The reaction temperature was gradually increased from 130 ° C to 150 ° C. Most of the toluene was removed while gradually raising the reaction temperature to 150 ° C., and the reaction was continued at 150 for 10 hours. Then, 10.0 g (0.040 mol) of 4,4′-DCBP was added, and the reaction was further continued for 5 hours. . The resulting reaction solution was allowed to cool, and then the by-product inorganic compound precipitate was removed by filtration, and the filtrate was put into 4 L of methanol. The precipitated product was separated by filtration, collected, dried, and dissolved in 300 mL of tetrahydrofuran. This was reprecipitated in 4 L of methanol to obtain 95 g (yield 85%) of the target compound.

The weight average molecular weight in terms of polystyrene determined by GPC (THF solvent) of the obtained polymer was 11,200. Further, the obtained polymer was soluble in THF, NMP, DMAc, sulfolane and the like, Tg was 110 ° C., and thermal decomposition temperature was 498 ° C.

  The obtained compound was an oligomer represented by the formula (I) (hereinafter referred to as “BCPAF oligomer”).

[Synthesis Example 2]
Preparation of polyarylene copolymer (PolyAB-SO ₃ neo-Pe) with neopentyl group as protecting group 1L three-neck equipped with a stirrer, thermometer, cooling pipe, Dean-Stark pipe, and three-way cock for introducing nitrogen In a flask, 39.58 g (98.64 mmol) of 4- [4- (2,5-dichlorobenzoyl) phenoxy] benzenesulfonate neo-pentyl (A-SO ₃ neo-Pe) and a BCPAF oligomer (Mn = 11) were added. , 200) 15.23 g (1.36 mmol), Ni (
PPh ₃ ) ₂ Cl ₂ 1.67 g (2.55 mmol), PPh ₃ 10.49 g (40 mmol), NaI 0.45 g (3 mmol), zinc dust 15.69 g (240 mmol), dry NMP 390 mL nitrogen Added below. The reaction system was heated with stirring (finally heated to 75 ° C.) and allowed to react for 3 hours. The polymerization reaction solution was diluted with 250 mL of THF, stirred for 30 minutes, filtered using Celite as a filter aid, and the filtrate was poured into 1500 mL of a large excess of methanol for solidification. The coagulum was collected by filtration, air-dried, redissolved in THF / NMP (200/300 mL each), and coagulated with 1500 mL of a large excess of methanol. After air drying, 47.0 g (yield 99%) of a copolymer (PolyAB-SO ₃ neo-Pe) composed of a sulfonic acid derivative protected with a target yellow fibrous neopentyl group was obtained by heat drying. The molecular weight by GPC was Mn = 47,600 and Mw = 159,000.

Thus obtained 5.1 g of PolyAB-SO ₃ neo-Pe was dissolved in 60 mL of NMP and heated to 90 ° C. To the reaction system, a mixture of 50 mL of methanol and 8 mL of concentrated hydrochloric acid was added at a time. While in suspension, the reaction was allowed to proceed for 10 hours under mild reflux conditions. A distillation apparatus was installed, and excess methanol was distilled off to obtain a light green transparent solution. This solution was poured into a large amount of water / methanol (1: 1 weight ratio) to solidify the polymer, and then the polymer was washed with ion exchange water until the pH of the washing water was 6 or more. From the IR spectrum of the polymer thus obtained and the quantitative analysis of the ion exchange capacity, it was found that the sulfonic acid ester group (—SO ₃ R ^a ) was quantitatively converted to the sulfonic acid group (—SO ₃ H). .
The molecular weight by GPC of the obtained polyarylene having a sulfonic acid group was Mn = 53,2
00, Mw = 185,000, and the sulfonic acid equivalent was 1.9 meq / g.

60 g of polyarylene having sulfonic acid obtained in Synthesis Example 2 was placed in a 1000 cc plastic bottle, and 442 g of γ-butyrolactone was added and dissolved. To this, 6 g of o-ethylphenylphosphoric acid (complexing amount: 10 parts by weight) was added, mixed for 20 minutes with a disperser, and uniformly dispersed.
The above solution was cast on a PET film by a bar coder method and dried at 80 ° C. for 30 minutes and 120 ° C. for 60 minutes to obtain a uniform solid electrolyte film A having a thickness of 40 μm. The results are shown in Table 1.

60 g of polyarylene having sulfonic acid obtained in Synthesis Example 2 was placed in a 1000 cc plastic bottle, and 442 g of γ-butyrolactone was added and dissolved. To this, 6 g of o-toluenesulfonic acid (composite amount: 10 parts by weight) was added, mixed for 20 minutes with a disperser, and uniformly dispersed.
The above solution was cast on a PET film by a bar coder method, and dried at 80 ° C. for 30 minutes and 120 ° C. for 60 minutes to obtain a uniform solid electrolyte film B having a thickness of 42 μm. The results are shown in Table 1.

[Comparative Example 1]
60 g of polyarylene having sulfonic acid obtained in Synthesis Example 2 was placed in a 1000 cc plastic bottle, and 340 g of γ-butyrolactone was added and dissolved.
The above solution was cast on a PET film by a bar coder method and dried at 80 ° C. for 30 minutes and at 120 ° C. for 60 minutes to obtain a uniform solid electrolyte film C having a thickness of 40 μm. The results are shown in Table 1.

[Comparative Example 2]
291.3 g of 20.6% water-alcohol solution (water: alcohol = 20: 60) of Nafion solution (trade name, manufactured by Dupont) was placed in a 1000 cc plastic bottle, and 108.7 g of N-propyl alcohol was added and dissolved. . To this, 6 g of o-ethylphenylphosphoric acid (complexing amount: 10 parts by weight) was added, mixed for 20 minutes with a disperser, and uniformly dispersed.
The above solution was cast on a PET film by a bar coder method and dried at 80 ° C. for 60 minutes to obtain a uniform solid electrolyte film D having a thickness of 44 μm. The results are shown in Table 1.

Claims (5)

(I) a polyarylene having a sulfonic acid group;
(Ii) A proton conducting membrane comprising at least one low molecular acid selected from the group consisting of low molecular phosphoric acid, low molecular phosphonic acid and low molecular sulfonic acid. The polyarylene having the sulfonic acid group includes a repeating structural unit represented by the following general formula (A) and, if necessary, a repeating structural unit represented by the following general formula (B). Item 1. A proton conducting membrane according to Item 1;
(In the formula, A represents a divalent electron-withdrawing group, B represents a divalent electron-donating group or a direct bond, Ar represents an aromatic group having a substituent represented by —SO ₃ H, m represents an integer of 0 to 10, n represents an integer of 0 to 10, and k represents an integer of 1 to 4.)
(In Formula (B), R ^{1 to} R ⁸ may be the same or different from each other, and are selected from the group consisting of a hydrogen atom, a fluorine atom, an alkyl group, a fluorine-substituted alkyl group, an allyl group, an aryl group, and a cyano group. And at least one kind of atom or group, W represents a divalent electron-withdrawing group or single bond, T represents a single bond or a divalent organic group, and p represents 0 or a positive integer.) .   3. The proton conducting membrane according to claim 1, wherein the low molecular acid is at least one selected from the group consisting of low molecular phosphoric acid and low molecular sulfonic acid.   The low molecular acid is contained in a proportion of 0.01 to 70 parts by weight with respect to 100 parts by weight of the polyarylene having the sulfonic acid group. The proton conducting membrane as described. (I) a polyarylene having a sulfonic acid group;
(Ii) at least one low molecular acid selected from the group consisting of low molecular phosphoric acid, low molecular phosphonic acid and low molecular sulfonic acid;
(Iii) A method for producing a proton conducting membrane, comprising producing a film by casting a solution composition containing a solvent on a substrate.