JP2009292947A - Substituted polyacetylene, method for producing it, electrolyte membrane, electrolyte membrane-electrode assembly, electrochemical device, and fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrolyte membrane exhibiting electrolyte properties sufficient for application to an electrochemical device, having heat resistance, oxidation resistance and mechanical strength sufficient for the application, containing no fluorine causing a high environmental load in disposal, and having excellent processability such as membrane formability. <P>SOLUTION: A substituted polyacetylene compound having a phosphonic acid group containing a repeating unit represented by formula (1) and the electrolyte membrane formed of this compound are provided. In the formula, part or all of R<SP>1</SP>-R<SP>6</SP>are phosphonic acid groups while the rest of them are selected from H, Br, Cl, I, a silicon-containing substituent, hydroxy group, 1-6C straight chain/branched chain alkyl/alkoxy group, phenoxy group, and sulfonic group. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention has a side chain containing a phosphonic acid group in the main chain made of polyacetylene, which is suitably used in various electrochemical devices such as a fuel cell, a secondary battery, a humidity sensor, an ion sensor, a gas sensor, and a desiccant agent. Or a substituted polyacetylene having a side chain containing a phosphonic acid group and a side chain containing a sulfonic acid group, a method for producing the same, an electrolyte membrane comprising the substituted polyacetylene, and an electrolyte membrane / electrode assembly using the electrolyte membrane, The present invention relates to an electrochemical device and a fuel cell.

  Solid electrolytes and electrolyte membranes are used in electrochemical devices such as fuel cells, secondary batteries, humidity sensors, ion sensors, gas sensors, and desiccants, and are the members that have the greatest impact on the performance of these electrochemical devices. . As an electrolyte material constituting such a member, a fluorine-based polymer having an acid dissociable functional group represented by Nafion (registered trademark) exhibits excellent performance in proton conductivity, mechanical properties, and chemical stability. Therefore, it is widely used. However, since this fluoropolymer has a low glass transition temperature of around 120 ° C., there is a restriction that the operating temperature of the fuel cell system must be 80 ° C. or less. Further, in general, a fluorine-based polymer has a high production cost, and since it contains fluorine, there is a problem that incineration disposal is difficult from the aspect of environmental burden during disposal.

  As electrolyte materials, other than fluorine-based polymers, aromatic polymers are mainly being developed. In particular, aromatic polymers with excellent heat resistance, mechanical properties, and chemical stability, such as polybenzimidazole, polysulfone, polyetheretherketone, polyamide, and polyimide, are used as the main chain skeleton of electrolyte materials. Yes.

  Many of these electrolytes composed of aromatic polymers have a wholly aromatic skeleton in order to increase resistance to hydrogen peroxide and hydroxy radicals generated in the fuel cell. However, these polymer main chains are rigid and have a property of being hardly soluble in an organic solvent, so that the film forming method is limited. Further, the film-like material has a low mechanical strength, and, for example, when used in a polymer electrolyte fuel cell, there is a problem that the film-like material is easily broken due to swelling and shrinkage due to a change in humidity during operation.

  On the other hand, polyacetylene (substituted polyacetylene) is obtained by coordination polymerization of an acetylene compound using a transition metal, and has a structure in which double bonds and single bonds are alternately connected to a main chain skeleton. In particular, polydiphenylacetylene having a trimethylsilyl group is soluble in a solvent and thus has excellent film forming properties and high heat resistance (see, for example, Patent Document 1). That is, the substituted polyacetylene is excellent in film forming properties as compared with a polymer having a wholly aromatic skeleton.

  Patent Document 2 discloses a method for obtaining a solid polymer electrolyte by introducing an ion dissociation group into substituted polyacetylene. This discloses a method of forming a film after reacting a polymerized substituted polyacetylene with a sulfonating agent, and a method of forming a film after polymerizing a monomer having a sulfonic acid group. However, in any of the methods, the sulfonated substituted polyacetylene is insoluble in a solvent and its film formation is difficult.

  Further, Patent Document 3 discloses a method of sulfonating polyacetylene, particularly a method of introducing sulfonic acid groups uniformly in the film thickness direction. As described in Patent Document 3, the present inventors previously introduced a bulky silyl group into polyacetylene, for example, a trimethylsilyl group, into a side chain and molded it into a film shape. It has been found that the sulfonic acid groups are uniformly introduced in the film thickness direction under a mild condition of around room temperature by dipping in a mixed solution of organic solvent and organic solvent. It is also disclosed that the resulting sulfonated polyacetylene membrane exhibits high proton conductivity. However, further improvement has been required for oxidation resistance and radical resistance, which are important physical properties as a solid electrolyte membrane for a polymer electrolyte fuel cell.

There are two methods for improving the oxidation resistance and radical resistance of the solid electrolyte membrane used in the polymer electrolyte fuel cell. The first method is a method in which a compound having a function of decomposing or trapping hydrogen peroxide is included in the film. For example, as disclosed in Patent Document 4, a catalyst metal particle is supported in a polymer electrolyte membrane, and hydrogen peroxide is decomposed. As disclosed in Patent Document 5, A transition metal oxide such as manganese oxide capable of decomposing peroxide radicals, or a compound having a phenolic hydroxyl group, and sulfonic acid contained in a sulfonated polyphenylene sulfide membrane as disclosed in Patent Document 6 Examples thereof include a technique for substituting a part of the group H (H ions) with Mg, Ca, etc., and a technique for containing Co ions.
In the method of containing the catalyst metal particles or the transition metal compound, a step of uniformly dispersing in the film is required, but if this is not successful, the film quality uniformity and the film surface smoothness may be impaired. Furthermore, there are a method of introducing a phenolic hydroxyl group, a method of supporting Mg and Ca by ion exchange, or a method of containing Co ions, but since the action mechanism is an irreversible reaction, there is an active substance contained. While it has an effect of improving the oxidation resistance and radical resistance, the effect (for example, durability) cannot be maintained after the entire amount of the contained active substance is consumed.

The second method is a method of introducing a functional group containing P such as a phosphoric acid group and a phosphonic acid group into a polymer substrate as disclosed in Patent Documents 8 and 9. Patent Document 8 discloses a method for obtaining an electrolyte membrane by graft polymerization of a small amount of a basic vinyl monomer and a phosphonic acid, vinylphosphonic acid or the like on a perfluoro-based polymer film substrate, and Patent Document 9 discloses a polystyrene film. An electrolyte membrane in which a phosphonic acid group is introduced into a graft-ethylenetetrafluoroethylene resin is disclosed.
These polymers are reported to have improved radical resistance by introducing a functional group containing P, but the graft side chain portion is a vinyl polymer. For this reason, H that tends to undergo a pulling-out reaction exists in the main chain portion, and it cannot sufficiently meet the requirements for radical resistance and oxidation resistance at a higher level.

On the other hand, examples of introducing a phosphonic acid group into a hydrocarbon polymer side chain include poly (phosphophenylene oxide) (Patent Document 10), phosphonated-poly (4-phenoxybenzoyl-1,4-phenylene) (patent Document 11) and phosphonated polybenzimidazole (Patent Document 12) have been proposed. However, polyphenylene oxide and polyparaphenylene are generally difficult to obtain a high molecular weight body, and since they have a wholly aromatic skeleton, they are difficult to dissolve in a solvent and are expected to have low processability during film formation. Further, even when the film is formed by any method, the resulting film is hard and brittle, and there is a concern that the mechanical strength is not sufficient. In addition, polybenzimidazole has a heterocyclic compound in the main chain and is obtained through a dehydration condensation reaction. Therefore, it is known that the hydrolysis reaction proceeds reversibly in high-temperature hot water, so that it has sufficient durability. It is thought that it does not have sex.
JP 2002-322293 A JP 2004-296141 A JP 2007-270028 A Japanese Patent Laid-Open No. 06-103992 JP 2001-118591 A JP 2004-018573 A JP 2006-210166 A JP 2007-66852 A JP 2000-11755 A JP 2007-238806 A JP 2004-175997 A JP 2003-327826 A

  Unlike vinyl polymers, polydiphenylacetylene is excellent in oxidation resistance and radical resistance because there is no H in the main chain that undergoes an extraction reaction by radicals or the like. Furthermore, the glass transition temperature is not observed up to the thermal decomposition temperature (generally 400 ° C. or higher), and it is known that the polymer is excellent in heat resistance. Therefore, if a functional group containing P can be introduced into the polydiphenylacetylene skeleton, unlike polymers having a wholly aromatic skeleton, vinyl polymers, and polymers having a heterocyclic ring, oxidation resistance, radical resistance, mechanical The present inventors paid attention to the possibility of a solid electrolyte membrane having excellent strength. As a method for synthesizing a polyacetylene having a phosphoric acid group introduced, a method in which an acetylene monomer having a phosphoric acid group introduced is polymerized using a transition metal catalyst such as Ta is disclosed (for example, see Patent Document 2). P compounds are known to poison transition metal catalysts. Even in experiments conducted by the present inventors, it was not possible to polymerize an acetylene monomer having a phosphonic acid group or a phosphonic acid ester group introduced with a transition metal catalyst.

  The present invention has been made in view of the above circumstances, exhibits electrolyte characteristics sufficient for use in electrochemical devices, has sufficient heat resistance, oxidation resistance, radical resistance and mechanical strength, and is disposed at the time of disposal. Substituted polyacetylene that does not contain fluorine, which has a large environmental impact, and has excellent processability such as film-forming properties, a method for producing the same, an electrolyte membrane comprising the substituted polyacetylene, and an electrolyte membrane / electrode assembly (so-called MEA) using the electrolyte membrane : Membrane Electrode Assembly), and to provide an electrochemical device and a fuel cell using the same.

  In order to achieve the above object, the present invention provides a substituted polyacetylene having a side chain containing a phosphonic acid group in the main chain composed of polyacetylene.

  The present invention also provides a substituted polyacetylene having a side chain containing a phosphonic acid group and a side chain containing a sulfonic acid group in the main chain composed of polyacetylene.

  The present invention also provides the following formula (1):

[However, in the formula (1), a part or all of R ^{1 to} R ⁶ is a phosphonic acid group, and the rest are H, Br, Cl, I, a silicon-containing substituent, a hydroxyl group, a straight chain having 1 to 6 carbon atoms. Any one selected from the group consisting of a chain or branched alkyl group or an alkoxy group, a phenoxy group, and a sulfonic acid group. A substituted polyacetylene having a repeating unit represented by the formula:

In the substituted polyacetylene of the present invention, R ¹ , R ³ and R ⁵ in the formula (1) are H, R ² is a silicon-containing substituent or H, and either one or both of R ⁴ and R ⁶ Is a phosphonic acid group, and the remainder is any one selected from the group consisting of H, a methyl group, a sulfonic acid group, Br, Cl, and I.

In the substituted polyacetylene of the present invention, a part of R ^{1 to} R ³ in the formula (1) is a sulfonic acid group, the rest is H, and a part or all of R ^{4 to} R ⁶ is a phosphonic acid group. Also preferably, the remainder is any one selected from the group consisting of H, methyl group, Br, Cl and I.

In the present invention, at least one of R ^{1 to} R ³ in the formula (1) is a silicon-containing substituent, the rest is H, and a part or all of R ^{4 to} R ⁶ is a phosphonic acid group. Substitution with a phosphonic acid group and a sulfonic acid group by sulfonating a substituted polyacetylene that is any one selected from the group consisting of H, methyl group, Br, Cl, and I with a sulfonating agent Provided is a method for producing a substituted polyacetylene to obtain a polyacetylene.

  The present invention also provides an electrolyte membrane comprising the substituted polyacetylene according to the present invention.

  The present invention also provides an electrolyte membrane obtained by the method for producing a substituted polyacetylene according to the present invention and formed into a membrane, wherein the distribution of sulfonic acid groups in the membrane is uniform in the film thickness direction. To do.

  The electrolyte membrane of the present invention is preferably one in which the membrane is impregnated with imidazole, benzimidazole, triazole, pyrazole or derivatives thereof.

  The present invention also provides an electrolyte membrane / electrode assembly in which an electrode is provided on the electrolyte membrane according to the present invention or a composite membrane containing the electrolyte membrane.

  The present invention also provides an electrochemical device having the electrolyte membrane / electrode assembly according to the present invention.

  The present invention also provides a fuel cell having the electrolyte membrane / electrode assembly according to the present invention.

  According to the present invention, a substituted polyacetylene and an electrolyte membrane having excellent oxidation resistance and radical resistance, high proton conductivity, sufficient heat resistance, low swelling, and sufficient mechanical strength are provided. Obtainable. In addition, if the electrolyte membrane is impregnated with a heterocyclic compound, an electrolyte membrane showing good proton conductivity even at high temperature and low humidity can be obtained. Furthermore, since this electrolyte membrane does not contain fluorine, it can be disposed of by incineration, and has a feature that the environmental load is small at the time of disposal.

  Preferred uses of the substituted polyacetylene having a phosphonic acid group or the substituted polyacetylene having a phosphonic acid group and a sulfonic acid group obtained by the present invention include an electrolyte membrane obtained by forming these substituted polyacetylenes, and an electrode on the electrolyte membrane. An electrolyte membrane / electrode assembly to which is given. The electrolyte membrane / electrode assembly made of this substituted polyacetylene can be suitably used for various electrochemical devices. Examples of the electrochemical device include a fuel cell, a secondary battery, a humidity sensor, an ion sensor, a gas sensor, and a desiccant, and can be most suitably used particularly in a polymer electrolyte fuel cell.

  The substituted polyacetylene according to the present invention is characterized in that the main chain composed of polyacetylene has a side chain containing a phosphonic acid group, or a side chain containing a phosphonic acid group and a side chain containing a sulfonic acid group. .

  In the substituted polyacetylene according to the present invention, the main chain composed of polyacetylene has a polyene structure in which double bonds and single bonds are alternately connected to the skeleton. The main chain made of polyacetylene may be either trans or cis.

  In the substituted polyacetylene according to the present invention, examples of the side chain include a hydrocarbon group having at least one phosphonic acid group or both a phosphonic acid group and a sulfonic acid group. Examples of the base hydrocarbon group include a linear or branched hydrocarbon group such as a methyl group, an aromatic hydrocarbon group such as a cyclic hydrocarbon group, and a phenyl group. This side chain includes a phosphonic acid group and a sulfonic acid group in addition to a hydrocarbon group in which H of the hydrocarbon group serving as a base is substituted with at least one phosphonic acid group or sulfonic acid group, and the phosphonic acid group And various substituents other than sulfonic acid groups (eg, silicon-containing substituents, hydroxyl groups, linear or branched alkyl groups, alkoxy groups, phenyl groups, phenoxy groups, etc.) and halogens (eg, Br, Cl, I, etc.) It may be a substituted hydrocarbon group.

A preferred embodiment of the substituted polyacetylene according to the present invention is as shown in the formula (1). In formula (1), part or all of R ^{1 to} R ⁶ is a phosphonic acid group, and the rest are H, Br, Cl, I, a silicon-containing substituent, a hydroxyl group, a linear or branched chain having 1 to 6 carbon atoms Or an alkyl group, an alkoxy group, a phenoxy group, or a sulfonic acid group.
The silicon-containing substituent can be appropriately selected from various substituents containing Si, and examples thereof include a trimethylsilyl group, a triethylsilyl group, a triisopropylsilyl group, and a dimethylisopropylsilyl group. In the present invention, a particularly preferred silicon-containing substituent is a trimethylsilyl group.
Moreover, n in Formula (1) is a number of 2 or more, preferably a number in the range of 4 to 40,000, more preferably a number in the range of 200 to 20000. When n is less than 40, the resulting substituted polyacetylene film has insufficient mechanical strength, making it difficult to obtain a practical electrolyte membrane. Moreover, when n exceeds 20000, the solubility to an organic solvent will fall and film formation will become difficult.

  The substituted polyacetylene of the present invention has a structure having a side chain containing a phosphonic acid group and a side chain containing a phosphonic acid group and a side chain containing a sulfonic acid group in the main chain made of polyacetylene. An electrolyte membrane having excellent oxidation resistance and radical resistance, high proton conductivity, sufficient heat resistance, low swelling, and sufficient mechanical strength can be formed. In addition, if the heterocyclic compound is impregnated, an electrolyte membrane showing good proton conductivity even at high temperature and low humidity can be obtained. Furthermore, since this membrane does not contain fluorine, it can be disposed of by incineration, and has a feature that the environmental load is small when discarded.

Among the substituted polyacetylenes of the present invention represented by the formula (1), R ¹ , R ³ and R ⁵ in the formula (1) are H and R ² is a silicon-containing substituent or A substituent in which either one or both of R ⁴ and R ⁶ is a phosphonic acid group, and the remainder is selected from the group consisting of H, a methyl group, a sulfonic acid group, Br, Cl, and I Polyacetylene is mentioned.
The substituted polyacetylene represented by this structure is easy to obtain a synthetic starting material and is excellent in film formability because it is soluble in an organic solvent.

As another particularly preferable substituted polyacetylene, a part of R ^{1 to} R ³ in the formula (1) is a sulfonic acid group, the rest is H, and a part or all of R ^{4 to} R ⁶ is a phosphonic acid group. And substituted polyacetylene, the remaining being any one selected from the group consisting of H, methyl group, Br, Cl and I.

Next, an example of a method for producing a substituted polyacetylene according to the present invention will be described.
In order to obtain the substituted polyacetylene according to the present invention, as a first step, according to the following reaction formula (A), the compounds represented by the formulas (2) and (3) are used as starting materials, and represented by the formula (4). The substituted polyacetylene represented by the formula (5) that is soluble in an organic solvent is synthesized by polymerizing this through an intermediate. The organic solvent is not particularly limited but is preferably a dehydrating solvent such as toluene, tetrahydrofuran, diethyl ether or xylene.

However, X in the formula (2) is Cl, Br or I, and in the formulas (2) and (3), at least a part of R ^{7 to} R ¹² is any one of Cl, Br and I, and the rest At least one of them is trimethylsilyl group, triethylsilyl group, triisopropylsilyl group, dimethylisopropylsilyl group, phenoxy group, tert-butyldimethyloxy group, tert-butyldimethyloxyphenyl group, cyclohexyl group, N, N-diphenylamino. A group selected from the group consisting of a group, 3a, 7a-dihydro-1H-indolyl group, 3-methyl-3a, 7a-dihydro-1H-indolyl group, and the remainder being H, halogen atom, carbon It is a linear or branched alkyl group of formula 1-6.

  In addition, the introduction of the various substituents described above is performed by introducing the substituents into the halogenated arylene compound in a known manner in advance, or synthesizing the acetylene compound into which the substituents are introduced according to the following reaction formula (B). be able to.

That is, the halogenated arylene compound into which the substituents R ^{10 to} R ¹² represented by the formula (6) are introduced and 2-methyl-3-butyn-2-ol are subjected to a known coupling reaction, preferably a Sonogashira- Coupling is performed using the EBARA coupling method to obtain an acetylene compound represented by the formula (7). Thereafter, an excessive amount of a base such as sodium hydroxide or potassium hydroxide is added in toluene or benzene, and the mixture is refluxed for several hours, and separated and purified by a conventional method such as silica gel column chromatography or distillation. An acetylene compound into which the substituent represented by 3) is introduced can be synthesized. In addition, when an active group such as a hydroxyl group is introduced, it is preferably protected beforehand as tert-butyldimethylsiloxy group using tert-butyldimethylchlorosilane.

  The acetylene compound represented by the formula (3) obtained by the reaction formula (B) is a known coupling with the halogenated arylene compound represented by the formula (2) as shown in the reaction formula (A). Coupling is performed using a reaction, preferably the Sonogashira-Hagiwara coupling method, to obtain an acetylene compound represented by the formula (4).

  The substituted polyacetylene represented by the formula (5) in the reaction formula (A) is obtained by converting the acetylene compound represented by the formula (4) into a transition metal catalyst such as Nb, Ta, Mo, or W, or these catalysts. It can be obtained by heating and stirring in a dehydrating solvent using a promoter such as tetrabutyltin. Further, other known polymerization methods may be used. The molecular weight of the substituted polyacetylene represented by the formula (5) greatly affects the heat resistance and mechanical strength when used as an electrolyte membrane. If the molecular weight is too small, the heat resistance and mechanical strength are lowered, and if the molecular weight is too large, the solubility is lowered and the amount of solvent used for film formation is increased. Therefore, the molecular weight of the substituted polyacetylene is approximately 10,000. Should be in the range of -10 to 10 million, more preferably in the range of 50,000 to 5 million. The substituted polyacetylene represented by the formula (5) is not particularly limited as long as it contains the structure described above, and even a homopolymer obtained by polymerizing one kind of acetylene compound is obtained by polymerizing two or more kinds of acetylene compounds. A copolymer may be used.

  In the second step, a substituted polyacetylene having a phosphonate ester group in at least a part of the side chain is synthesized. The polymer can be obtained, for example, by the following procedure. The substituted polyacetylene having halogen in at least a part represented by the formula (5) is added to any of dehydrating solvents such as toluene, tetrahydrofuran, diethyl ether, and xylene, and heated and stirred to dissolve a part or all of them. Thereafter, an appropriate amount of nickel chloride (II) and a phosphate ester such as trimethyl phosphate, triethyl phosphate, or triphenyl phosphate are added and heated to 100 to 200 ° C, preferably 150 to 200 ° C. (Arbuzov reaction). Or a palladium catalyst (eg, tetrakistriphenylphosphine palladium), a phosphite (eg, trimethyl phosphite, triethyl phosphite, or triphenyl phosphite) and a base (eg, triethylamine or pyridine) ) And heated and stirred. The heating temperature is 50 to 200 ° C., preferably 100 to 150 ° C., and is obtained by stirring for 2 hours or more, preferably 24 to 144 hours.

  Alternatively, a substituted polyacetylene having a phosphonic acid ester group in part can be obtained by a reaction using palladium acetate as a catalyst. The substituted polyacetylene having halogen in at least a part represented by the formula (5) is added to any of dehydrating solvents such as toluene, tetrahydrofuran, diethyl ether, and xylene, and heated and stirred to dissolve a part or all of them. Thereafter, an appropriate amount of palladium acetate, triphenylphosphine and phosphite (for example, trimethyl phosphite, triethyl phosphite, triphenyl phosphite) and a base such as triethylamine or pyridine are added, and 50 to It can also be obtained by stirring at 200 ° C., preferably 100 to 150 ° C. for 2 hours or longer, preferably 24 to 144 hours. In addition, after dissolving the substituted polyacetylene having halogen in at least a part represented by the formula (5) in the above-mentioned dehydrating solvent, after cooling to −78 to 35 ° C., preferably 0 to 25 ° C., alkyl lithium, for example, n-Butyllithium, sec-Butyllithium, or tert-Butyllithium is added, and a halogenated phosphoric acid ester such as dimethyl chlorophosphate, diethyl chlorophosphate, or diphenyl chlorophosphate is added, and the temperature is 0 to 60 ° C. Preferably, it can also be obtained by stirring at 25 to 40 ° C. for several hours. In addition, other known reactions for introducing a phosphonate group can be used.

  The obtained polymer was dissolved in a phosphorus compound such as methanol, hexane, diethyl ether, and acetone, and injected into a solvent that did not dissolve polydiphenylacetylene having a phosphonate ester group introduced therein, followed by reprecipitation purification. can get. The palladium catalyst remaining in the polymer can be removed by repeated reprecipitation purification and Soxhlet extraction using the solvent used for the purification, preferably acetone.

  In the third step, a substituted polyacetylene having a phosphonate ester group introduced at least in part is molded into a film. The obtained polydiphenylacetylene into which the phosphonic acid ester group is introduced is soluble in an organic solvent such as tetrahydrofuran and toluene, and is a known film forming method such as a solvent casting method, a spin coating method, a transfer method, a printing method, etc. In addition to the film forming method according to the above, it can be formed into a film shape by combining heat treatment and mechanical treatment such as rolling / stretching as necessary.

  In the fourth step, the phosphonic acid ester group of the film is deprotected to synthesize a substituted acetylene film having a phosphonic acid group. By heating the membrane in a strong acid such as hydrobromic acid, concentrated sulfuric acid, methanesulfonic acid, concentrated hydrochloric acid or the like for 2 to 72 hours, preferably 24 to 48 hours, phosphon The acid ester group becomes a phosphonic acid group by the progress of the deprotection reaction, and a substituted polyacetylene film having a phosphonic acid group can be obtained.

  As a different method for the deprotection reaction, a known hydrolysis reaction such as a reaction using trimethylsilyl iodide can be used in addition to the reaction using the strong acid. In addition, since substituted polyacetylene having a phosphonic acid group is soluble in an organic solvent such as toluene and tetrahydrofuran, the substituted polyacetylene having a phosphonic acid ester group introduced therein is deprotected by the above-described method to obtain a substituted polyacetylene having a phosphonic acid group. After conversion into a known film-forming method, for example, a solvent casting method, a spin-coating method, a transfer method, a film-forming method by a printing method, etc., as needed, heat treatment, mechanical treatment such as rolling / stretching, etc. You may shape | mold into a film form combining a process. When a silicon-containing substituent such as a trimethylsilyl group is introduced into a part of the substituted polyacetylene introduced with a phosphonic acid ester group, the elimination reaction of the silicon-containing substituent may occur when heated in a strong acid. There is.

  When it is desirable to make the substituted polyacetylene having a phosphonic acid group introduced after deprotection more soluble in an organic solvent, a mixed solvent of the strong acid and an organic solvent such as ethyl acetate or diethyl ether is used. Heating may leave the silicon-containing substituents. A preferable concentration of the strong acid in the mixed solution is 50 to 95% by mass. The silicon-containing substituent can also be left by changing reaction conditions such as reaction time and reaction temperature. Furthermore, as another method, a known reagent such as trimethylsilyl iodide for allowing the ester deprotection reaction to proceed selectively may be used.

  Furthermore, when high proton conductivity is required for the electrolyte membrane from the design of fuel cells, secondary batteries, humidity sensors, ion sensors, gas sensors, desiccants, etc., substituted polyacetylene membranes having phosphonate ester groups ( Polydiphenylacetylene membrane) with concentrated sulfuric acid, mixed solution of concentrated sulfuric acid and solvent, for example, ethyl acetate, diethyl ether, etc., fuming sulfuric acid, sulfur trioxide-dioxane, sulfur trioxide-pyridine, chlorosulfonic acid or sulfurous acid such as sulfurous acid A sulfonic acid group can be introduced by contacting with an agent. At this time, it is desirable to introduce a silicon-containing substituent such as a trimethylsilyl group in advance into a substituted polyacetylene film (polydiphenylacetylene film) having a phosphonate group. The bulky silicon-containing substituent causes voids between polymer chains, and the sulfonating agent easily penetrates into the membrane, so that sulfonic acid groups can be introduced uniformly in the film thickness direction.

  In the case of sulfonation in the liquid phase, a solvent or a surfactant can be used as necessary. The solvent and the surfactant are not particularly limited as long as the properties of the membrane and the control of sulfonation are not adversely affected. Examples of the solvent include water, alcohols having 1 to 8 carbon atoms, ethyl acetate, butyl acetate, Chloroform, dichloromethane, 1,2-dichloroethane, formic acid, acetic acid, butyric acid, acetic anhydride, chloroacetic acid, trifluoroacetic acid, trifluoroacetic anhydride, nitrobenzene and the like can be used alone or in admixture of two or more. Surfactants include salts of quaternary ammonium ions such as tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium and the like with chloride ions, bromide ions, iodide ions, hydrogen sulfate ions, etc., or nonanylbenzene Single or two or more ionic surfactants such as sodium salts and ammonium salts such as sulfonic acid, lauryl sulfate, and benzoic acid, and nonionic surfactants such as propylene glycol and polyoxyethylene glycol monolauryl ether It can be used by mixing.

  When sulfonating in the gas phase, for example, the membrane may be directly exposed to sulfurous acid gas. In this case, as a control or mobile phase of the sulfonated atmosphere, nitrogen gas, air, the above-mentioned solvent vapor, or the like can be used alone or in combination. The amount of sulfonation reagent, the amount of solvent and surfactant, the amount of gas, the time required for the sulfonation treatment, temperature, etc. depend on the influence on the properties of the membrane and the electrochemical characteristics required for the target electrochemical device. The amount of sulfonation may be determined based on the amount of sulfonation, and the processing time may be from several minutes to several hours in consideration of production efficiency.

  Among the sulfonating agents, concentrated sulfuric acid or a mixed solution of concentrated sulfuric acid and a solvent that is industrially inexpensive, relatively easy to handle, and reusable is preferable. The solvent mixed with concentrated sulfuric acid is not particularly limited as long as it does not react with concentrated sulfuric acid. For example, any of the solvents described above can be used. The density | concentration of concentrated sulfuric acid is 20-100 mass% of concentrated sulfuric acids, Preferably it is 50-100 mass%, More preferably, it is 80-100 mass%.

  When the substituted polyacetylene membrane having a phosphonate ester group introduced therein is immersed in these sulfonating agents, the membrane may be previously immersed in a solvent and swollen. The solvent for swelling is not particularly limited as long as the film does not dissolve, and examples thereof include ethyl acetate and diethyl ether. Furthermore, the temperature at which the substituted polyacetylene film into which the phosphonic acid ester group is introduced is immersed is not particularly limited as long as it is not higher than the boiling point of the solvent used, but is preferably −30 to 200 ° C., more preferably 0 to 100 ° C. It is. In the present invention, the introduced sulfonic acid group is introduced to the inside and is uniform in that the sulfonic acid group distribution (sulfur atom) in the film thickness direction is determined by SEM-EDS (Scanning Electron Microscope-Energy Dispersive X-ray Spectrometer). (Based on S), the intensity of the characteristic X-ray (SKa) of the sulfur in the center of the film is 50% or more, more preferably 70% or more, more preferably 80% of the maximum value of SKa in the measurement range. It means that it is more than%.

  After introducing a sulfonic acid group, the phosphonic acid ester group is converted to a phosphonic acid group by the above deprotection reaction, thereby exhibiting excellent oxidation resistance and radical resistance, and high proton conductivity and high heat resistance. A substituted polyacetylene film having a phosphonic acid group and a sulfonic acid group having a low degree of swelling and sufficient mechanical strength can be obtained.

The electrolyte membrane comprising the substituted polyacetylene membrane of the present invention has excellent oxidation resistance and radical resistance, high proton conductivity, sufficient heat resistance and low swelling, and sufficient mechanical strength. is doing.
In addition, the electrolyte membrane comprising the substituted polyacetylene membrane of the present invention is impregnated with a heterocyclic compound showing basicity such as imidazole, benzimidazole, triazole, pyrazole, and their derivatives, thereby allowing high proton conductivity at high temperature and low humidity. It will have a degree.
Furthermore, since this electrolyte membrane does not contain fluorine, it can be disposed of by incineration, and has a feature that the environmental load is small at the time of disposal.

  In the current polymer electrolyte fuel cell, since Nafion (registered trademark) does not exhibit high proton conductivity unless it is under high humidification conditions, hydrogen and air (oxygen) are supplied to the power generation cell after being humidified by a humidifier. The Humidity control at high temperature requires a measuring instrument such as a dew point meter, leading to an increase in cost. Therefore, a more simplified humidifier and a solid electrolyte membrane that can be used under low humidity conditions are desired. Substituted polyacetylene membranes having phosphonic acid groups or phosphonic acid groups and sulfonic acid groups exhibit sufficient proton conductivity, but in order to impart high proton conductivity that functions under lower humidity conditions, pyrrole, Thiazole, isothiazole, oxazole, isoxazole, pyridine, imidazole, imidazoline, pyrazole, 1,3,5-triazine, pyrimidine, pyritadine, pyrazine, indole, quinoline, isoquinoline, brine, benzimidazole, benzoxazole, benzthiazole, tetrazole , Tetrazine, triazole, carbazole, acridine, quinoxaline, quinazoline, a nitrogen-containing heterocyclic compound composed of quinazoline, or a compound selected from the group consisting of these derivatives may be impregnated. Among these, basic molecules such as imidazole, benzimidazole, triazole, pyrazole and derivatives thereof are preferable.

  As a method for impregnating the electrolyte membrane, an appropriate amount of nitrogen-containing solvent is used such as pure water, methanol, ethanol, tetrahydrofuran, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, acetone and the like. Examples include a method of introducing a nitrogen-containing heterocyclic compound into the electrolyte membrane by dissolving the heterocyclic compound, immersing the electrolyte membrane made of the substituted polyacetylene in the solution, and stirring the electrolyte membrane. Since the nitrogen-containing heterocyclic compound in the electrolyte membrane forms a hydrogen bond with the phosphonic acid group or sulfonic acid group, it does not elute out of the electrolyte membrane. By introducing the nitrogen-containing heterocyclic compound into the electrolyte membrane, high proton conductivity that functions even under low humidity can be imparted. The introduction amount of the nitrogen-containing heterocyclic compound is preferably an amount corresponding to 0 to 3 times mol, and an amount corresponding to 1 to 2 times mol of the total mol of the phosphonic acid group or the phosphonic acid group and the sulfonic acid group. More preferred. If the introduction amount of the nitrogen-containing heterocyclic compound is not sufficient, the effect of improving proton conductivity is small and high proton conductivity cannot be imparted under low humidity conditions. On the other hand, if the introduction amount is excessive, the nitrogen-containing heterocyclic compound may be eluted out of the electrolyte membrane during power generation.

  The electrolyte membrane according to the present invention can produce an electrolyte membrane / electrode assembly using a known method. For example, an electrolyte membrane / electrode assembly can be produced by arranging catalyst particles, a gas diffusion electrode, and a supporting current collector on both sides of the electrolyte membrane to form a composite. As the catalyst particles, for example, platinum-supported carbon particles can be used. As the gas diffusion electrode, for example, a gas produced by firing a mixture of a water-repellent material and a binder and molding it into a sheet shape. A diffusion electrode can be used. Further, as the supporting current collector, for example, carbon paper or carbon woven fabric can be used. These are coated or impregnated with Nafion (registered trademark) or the like to form a composite, and the electrolyte membrane is sandwiched between the composites from both sides and hot-pressed to be processed into an electrolyte membrane / electrode assembly.

  The obtained electrolyte membrane / electrode assembly can be applied to various electrochemical devices such as fuel cells, secondary batteries, humidity sensors, ion sensors, gas sensors, desiccant agents, and the like. For example, a single cell of a fuel cell is manufactured by sandwiching the electrolyte membrane / electrode assembly from both sides with a bipolar plate in which a flow path of hydrogen or air is formed, and a fuel cell stack is formed by stacking the cells. Can be processed.

EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to this. In Comparative Examples and Examples, the method for producing the electrolyte membrane (hereinafter abbreviated as membrane) was described in the order of monomer synthesis, polymer synthesis, and film formation method. The ¹ H-NMR spectrum, FT-IR spectrum, molecular weight, film thickness, phosphorus and halogen content, ion exchange capacity, water content, swelling degree, proton conductivity and softening point were determined as follows. The Fenton test was performed according to the following procedure.

1. ¹ H-NMR spectrum Measurement was performed using a nuclear magnetic resonance apparatus (manufactured by Burker Biospin, trade name: AVNCE DRX 400).

2. FT-IR spectrum The FT-IR spectrum was measured by the KBr disc method using a FT-IR measuring apparatus (trade name PARAGON FT-IR, manufactured by PERKINELMER).

3. Molecular weight The molecular weight of the compound was measured by a gas chromatography mass spectrometer (HP-5890 / HP-5971, manufactured by Hewlett-Packard).

4). Measurement of Polymer Molecular Weight The obtained polymer was dissolved in tetrahydrofuran (THF), and the number average molecular weight and the mass average molecular weight were measured by gel permeation chromatography (GPC) (trade name HLC-8220-GPC, manufactured by Tosoh Corporation). The eluent was THF, and polystyrene was used as a standard sample.

5. Film thickness After vacuum drying a given film at 110 ° C. for 16 hours, the film thickness meter (manufactured by Mitutoyo, trade name: Quick Micro) was used to measure the circumference and 5 points of the center and calculate the average value. did.

6). Phosphorus and Halogen Content A predetermined mass of polymer or membrane was combusted in a closed Erlenmeyer flask, and the combustion gas was absorbed in a predetermined amount of 3% aqueous hydrogen peroxide. The absorbing solution was measured using an ion chromatograph ICS-3000 (manufactured by DIONEX), and the contents of phosphorus and halogen were calculated by the following formula (a).
Phosphorus or halogen content (mass%) = [phosphorus or halogen concentration in sample (ppm)] × [absorbed liquid amount (L)] / [sample mass (mg)] × 100 (a)

7). Ion exchange capacity A predetermined amount of the membrane was vacuum dried at 110 ° C. for 16 hours, and mass measurement was performed. Thereafter, the membrane was immersed in 50 mL of a 0.1 mol / L sodium chloride aqueous solution and gently stirred for 16 hours. Next, the membrane was taken out and titrated with a 1 / 50N sodium hydroxide aqueous solution (N represents the normality of the standard solution). For the titration, an automatic titration apparatus (manufactured by Toa Denpa Kogyo Co., Ltd., trade name: AUT-501) was used, and the inflection point of the titration curve was used as the neutralization point (end point), and the ion exchange capacity was calculated according to the following formula (b). . In addition, the same operation was performed 3 times and the total value was made into the ion exchange capacity.
Ion exchange capacity (meq / g) = [0.02 × factor × 1 / 50N sodium hydroxide aqueous solution consumption (mL)] / [membrane mass (g)] (b)

8). Moisture content A predetermined amount of the membrane was boiled in 1.0 mol / L sulfuric acid aqueous solution for 1 hour, and further boiled in pure water for 1 hour, and then the mass of the membrane was measured. Next, the membrane was vacuum-dried at 110 ° C. for 16 hours and then mass measurement was performed, and the water content was calculated according to the following formula (c).
Moisture content (%) = [mass of hydrous film (g) −mass at drying (g)] / [mass at drying (g)] × 100 (c)

9. Swelling degree A predetermined amount of the film was boiled with 1.0 mol / L sulfuric acid aqueous solution for 1 hour, and further boiled with pure water for 1 hour, and then the size (length × width × thickness) of the film was measured. Next, the membrane was vacuum-dried at 110 ° C. for 16 hours, then the size of the membrane was measured, and the degree of swelling was calculated according to the following formula (d).
Swelling degree (%) = [volume at the time of swelling (mm ³ )] / [volume at the time of drying (mm ³ )] × 100 (d)

10. Proton conductivity The membrane was cut into a size of 2 cm × 5 cm and boiled in a 1 mol / L sulfuric acid aqueous solution for 1 hour. Subsequently, after boiling with distilled water for 1 hour, it is closely attached to a 4 cm long gold electrode spaced 0.5 cm apart and controlled to 90 ° C. and relative humidity (RH) 90% in a constant temperature and humidity chamber. However, the impedance was measured in the frequency range of 0.5 Hz to 10 MHz using an impedance analyzer (trade name Solatoron 1260, manufactured by Toyo Corporation). Impedance was obtained from the obtained Nyquist Plot, and proton conductivity was calculated according to the following formula (e).
Proton conductivity (S / cm) = [0.5 (cm)] / [impedance (Ω) × (4 (cm)) × film thickness (cm)] (e)

11. Measurement of softening point The film was cut into 1 cm × 1 cm, and a needle was contacted with a load of 50 g using a thermomechanical measuring device (manufactured by Shimadzu Corporation, TMA-60), and the temperature was raised to 400 ° C. at a temperature rising rate of 10 ° C./min. . The penetration temperature of the needle was taken as the softening point.

12 Fenton test 50 mL of a Fenton solution (4 ppm, Fe ²⁺ , 3% hydrogen peroxide solution) was prepared, the film was cut into a predetermined size, the mass was measured, and then immersed at 68 ° C. for 24 hours. Thereafter, the membrane was boiled with 1 mol / L sulfuric acid aqueous solution for 1 hour, and further boiled with pure water for 1 hour. After vacuum drying at 110 ° C. for 12 hours or more, mass measurement was performed to determine a mass change before and after the reaction.

{Comparative Example 1}
[Synthesis of Monomer M-1]
Monomer (M-1) was synthesized according to the following reaction formula (C).

  Under an argon atmosphere, 4.3 g (14 mmol) of 1-bromo-4-phosphate diethylbenzene, 55 mg (0.21 mmol) of triphenylphosphine, 30 mg (0.043 mmol) of dichlorobis (triphenylphosphine) palladium, 8.2 mg of copper iodide (0.043 mmol) and 7.2 mL (2.0 mol / L) of triethylamine dehydrated with calcium hydride were added and stirred, and then 1.8 mL (16 mmol) of phenylacetylene was added and stirred at 90 ° C. for 1 hour. . Triethylamine was distilled off, diethyl ether was added in excess, and the mixture was stirred. Insoluble materials were filtered off, and the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography (developing solvent hexane: ethyl acetate = 30: 70, v / v) to obtain 4.1 g of monomer M-1 (yield: 92%).

¹ H-NMR, δ (ppm, CDCl ₃ , 400 MHz): 1.32 (6H, t, CH ₃ ), 4.12 (4H, m, CH ₂ ), 7.35 (3H, m, Ph), 7.53 (2H, m, Ph), 7.61 (2H, m, Ph), 7.78 (2H, m, Ph).

^{IR, ν (cm -1, KBr} disk): 3476 (m), 3062 (w, arC-H), 2984 (m, alC-H), 2932 (w, alC-H), 2906 (m, alC- H), 2219 (w, C≡C), 1602 (s, arC-C), 1505 (w, arC-C), 1443 (m, alC-H), 1393 (m, alC-H), 1251 ( s, P = O), 1164 (m), 1149 (m), 1121 (s), 1100 (m), 1052 (s), 1023 (s, P-O-C), 968 (s, P-O) -C), 835 (m), 796 (m), 759 (s, arC-H), 692 (m, arC-C), 621 (s), 554 (m), 541 (m), 526 (m ).

[Polymerization of Monomer M-1]
Monomer M-1 0.20 g (0.64 mmol) obtained by synthesis as described above was weighed into an eggplant flask, 9.3 mg (0.026 mmol) of tantalum pentachloride (V) in a glove box, n- Tetrabutyltin (IV) 17 μL (0.052 mmol) was added. Thereafter, 1.3 mL (0.5 mol / L) of dehydrated toluene was added and stirred at 80 ° C. for 24 hours. When the obtained solution was poured into methanol, no precipitate was observed. Therefore, the solvent was distilled off, and the residue was purified by silica gel column chromatography (developing solvent hexane: ethyl acetate = 30: 70, v / v). As a result, 0.19 g of monomer M-1 (recovery: 95%) Was recovered. Therefore, it is clear that the polymerization reaction of the monomer M-1 did not proceed.

{Comparative Example 2}
[Synthesis of Monomer M-2]
A monomer represented by the following formula (M-2) was synthesized.

  Monomer M-2 was synthesized in the same procedure as Comparative Example 1 except that 1-bromo-4-phosphate diphenylbenzene was used instead of 1-bromo-4-phosphate diethylbenzene. The yield was 24%.

¹ H-NMR, δ (ppm, CDCl ₃ , 400 MHz): 7.22 (6H, m, Ph), 7.39 (4H, m, Ph), 7.46 (3H, m, Ph), 7. 60 (2H, m, Ph), 7.76 (2H, m, Ph), 7.97 (2H, m, Ph).

IR, ν (cm ⁻¹ , KBr disk): 3064 (m, arC—H), 2219 (m, C≡C), 1599 (s, arC—C), 1489 (s, arC—C), 1456 ( m), 1443 (m), 1397 (m), 1280 (s, P = O), 1268 (s, P = O), 1213 (s), 1188 (s, P-O-C), 1163 (s) ), 1120 (s), 1071 (m), 1026 (m), 1007 (m), 933 (s, P—O—C), 833 (m), 756 (s, arC—H), 689 (s) , ArC-C), 627 (s), 569 (m), 549 (m), 525 (s).

[Polymerization of monomer M-2]
In the same procedure as in [Polymerization of monomer M-1] in Example 1, after reacting monomer M-2 synthesized as described above, the solvent was distilled off and the residue was subjected to silica gel column chromatography (developing solvent hexane). : Ethyl acetate = 80: 20, v / v), 0.21 g of monomer M-2 (recovery rate: 81%) was recovered. Therefore, it is clear that the polymerization reaction of the monomer M-2 did not proceed.

{Comparative Example 3}
[Synthesis of Monomer M-3]
Monomer M-3 in the following reaction formula (D) was synthesized.

Under an argon atmosphere, 17 mg (0.024 mmol) of bis (triphenylphosphine) palladium (II) dichloride, 23 mg (0.12 mmol) of copper iodide, and 32 mg (0.12 mmol) of triphenylphosphine were weighed into a 200 mL three-necked flask. Thereafter, 70 mL (0.50 mmol) of triethylamine previously dehydrated with calcium hydride was added. Furthermore, 1.6 mL (8.0 mmol) of 1-bromo-4- (trimethylsilyl) benzene and 0.90 mL (8.0 mmol) of phenylacetylene were added and stirred at 90 ° C. for 16 hours. Then, triethylamine was distilled off, diethyl ether was added and filtered. Next, the filtrate was concentrated and purified using silica gel column chromatography (solvent: hexane). Then, when refine | purifying using an alumina column chromatography (solvent: hexane), 1.2 g (yield: 61%) of the transparent viscous liquid was obtained. ¹ H-NMR and IR measurements confirmed that the liquid was M-3.

¹ H-NMR, δ (ppm, CDCl ₃ , 400 MHz): 0.28 (9H, s, CH ₃ × 3), 7.33 (2H, m, Ph), 7.35 (1H, m, Ph) , 7.50 (4H, s, Ph), 7.53 (2H, m, Ph).

IR, ν (KBr disk, cm ⁻¹ ): 3065 (w), 2956 (m, C—H), 2219 (vw, C≡C), 1601 (m, ar C—C), 1249 (s), 1101 (W), 855 (s, Si-C), 839 (s), 820 (s), 755 (m), 690 (s), 627 (w), 633 (m).

[Synthesis of Polymer P-3]
According to the reaction formula (D), the monomer M-3 was polymerized to synthesize a polymer P-3.
In a glove box, 55 mg (0.15 mmol) of tantalum pentachloride (V) and 0.10 mL (0.31 mmol) of tetrabutyltin (IV) were added to a 50 mL eggplant flask. Further, 4.0 mL of dehydrated toluene was added and stirred at 80 ° C. for 20 minutes to age the catalyst solution. Further, 1.0 g (4.0 mmol) of the monomer M-3 was weighed into a 50 mL eggplant flask under an argon atmosphere, and 4.0 mL of dehydrated toluene was added to prepare a monomer solution. Next, the monomer solution was added to the catalyst solution with a cannula and stirred at 80 ° C. for 2 hours. The obtained solution was diluted, and this was poured into methanol for precipitation, to obtain 0.70 g (yield: 73%) of a yellow fibrous product. The obtained substance was confirmed to be polymer P-3 by IR measurement. Further, the average molecular weight was measured by GPC (gel permeation chromatography).

IR, ν (cm ⁻¹ , KBr disk): 3055 (w, arC—H), 3017 (w), 2957 (s, C—H), 1646 (vw,> C = C <), 1597 (w, arC-C), 1494 (w), 1248 (s), 1118 (m), 855 (s, Si-C), 835 (s), 814 (s), 755 (s), 689 (s), 630 (W), 554 (s).

GPC measurement results: Mn = 6.0 × 10 ⁵ , Mw = 6.1 × 10 ⁵ , Mw / Mn≈1.

[Polymer P-3 Film Formation]
In a 300 mL eggplant flask, 0.2 g of the polymer P-3 prepared as described above was weighed, 50 mL of toluene was added, and the mixture was dissolved at 100 ° C. for 16 hours. Thereafter, a frame made of polytetrafluoroethylene having a width of 1 cm was attached to the periphery of a 10 cm × 10 cm glass plate installed horizontally in a thermostat, and a toluene solution of polymer P-3 was cast. The film was allowed to stand at 60 ° C. for 3 days to obtain a strong film P-3 having a film thickness of 29 μm.

[Sulfonation of membrane P-3]
In a 100 mL eggplant flask, 50 mL of concentrated sulfuric acid (97% by mass) was weighed, 69 mg of membrane P-3 formed as described above was immersed, and gently stirred at room temperature for 3 hours. After removing the membrane, the membrane was washed with water and further boiled with pure water for 1 hour. Then, it vacuum-dried at 110 degreeC for 16 hours, and obtained green film | membrane PS-3 by which the film | membrane P-3 was sulfonated. It was confirmed by IR (infrared spectroscopy) measurement that the desilylation reaction and the sulfonation reaction proceeded in the membrane PS-3.

IR, ν (cm ⁻¹ , KBr disk): 3056 (w, arC-H), 1642 (m, arC-C), 1492 (s, arC-C), 1442 (w), 1218 (s), 1154 (S), 1128 (w, SO ₃ H), 1033 (w, SO ₃ H), 1005 (w), 907 (w), 825 (w), 755 (s), 691 (s), 572 (m ).

[Physical properties of membrane PS-3]
As described above, the membrane PS-3 obtained by sulfonation of the membrane P-3 has a film thickness of 29 μm, an ion exchange capacity of 2.3 meq / g, a water content of 80%, a swelling degree of 282%, and a proton conductivity of 3.7. × 10 ⁻¹ S / cm (90 ° C., relative humidity 90%).

{Example 1}
[Synthesis of Monomer M-4]
Monomer M-4 was synthesized according to the following reaction formula (E).

  In a 100 mL three-necked flask under an argon atmosphere, 0.02 g (0.03 mmol) of dichlorobis (triphenylphosphine) palladium (II) dichloride, 0.04 g (0.15 mmol) of triphenylphosphine and 0.02 g of copper (I) iodide ( 0.10 mmol) was weighed out and 8.6 g (30 mmol) of the compound 1-bromo-4-iodobenzene was added. Thereafter, 60 mL of triethylamine (TEA) dehydrated with calcium hydride was added, and 5.2 g (30 mmol) of 1-ethynyl-4-trimethylsilylbenzene was further added, followed by stirring at 90 ° C. for 24 hours. After evaporation of triethylamine, diethyl ether was added in excess to extract the product and filtered. The obtained extract was washed successively with saturated saline and pure water, and then dehydrated with sodium sulfate. The filtrate was distilled off under reduced pressure using an evaporator and then purified by silica gel column chromatography (solvent: n-hexane) to obtain 8.9 g of monomer M-4. The yield was 91%.

¹ H-NMR, δ (ppm, CDCl ₃ , 400 MHz): 0.2 (9H, CH ₃ × 3), 7.3 (2H, Ph), 7.4 (2H, Ph), 7.5 (4H , Ph).

IR, ν (cm ⁻¹ , KBr disk): 3067 (w, C—H st), 3021 (w), 2958 (m, C—H st), 2896 (w), 2220 (s, —C≡C -), 1392 (w, arC-C), 1305 (w, arC-C), 1247 (s, Si-H), 1099 (w), 908 (w), 838 (s, Si-C), 823 (S, Si-C), 756 (s), 715 (m), 517 (m).

GC-MS (M / Z) ^<+> : 330, 315.

[Synthesis of Polymer P-4]
To a two-necked flask purged with argon in a glove box were added 0.23 g (0.64 mmol) of tantalum pentachloride (V) and 0.42 mL (1.3 mmol) of n-tetrabutyltin (IV). Further, 22 mL of dehydrated toluene was added and stirred at 80 ° C. for 15 minutes to age the catalyst. In addition, 2.1 g (6.4 mmol) of monomer M-4 was weighed into an eggplant flask and purged with argon, and then 10 mL of toluene was added to prepare a monomer solution. Thereafter, the monomer solution was added to the catalyst solution with a cannula and stirred at 90 ° C. for 24 hours, and then this solution was added to methanol. The obtained precipitate was recovered and dissolved again in toluene, and this solution was poured into methanol to obtain a precipitate. The precipitate was filtered off to obtain 1.7 g of polymer P-4. The yield was 82%.

IR, ν (cm ⁻¹ , KBr disk): 3067 (w), 3013 (w), 2955 (m, C—H st), 2897 (w), 1585 (w, arC-C), 1484 (s) , 1389 (m), 1248 (s, SiC-H), 1114 (s), 1075 (m), 1010 (m), 856 (s, Si-C), 835 (s, Si-C), 816 ( s), 756 (s), 715 (s), 693 (s), 553 (w).

GPC: Mn = 1.1 × 10 ⁶ , Mw = 2.0 × 10 ⁶ , Mw / Mn≈1.8.

[Introduction of phosphonate ester group (1)]
Under an argon atmosphere, 0.5 g (1.5 mmol) of the polymer P-4 prepared as described above was weighed, 60 mL of toluene was added, and the mixture was stirred and dissolved at 100 ° C. for 15 hours. To this solution were added diethyl phosphite 3.9 mL (30 mmol), tetrakistriphenylphosphine palladium 2.6 g (2.3 mmol) and dehydrated triethylamine 10 mL, and the mixture was stirred at 100 ° C. for 4 days. Thereafter, this solution was poured into n-hexane, and the resulting precipitate was purified by reprecipitation twice. The resulting precipitate was filtered off and dried in vacuo at 60 ° C. for 6 hours. Then, it boiled for 24 hours in 10 mass% hydrochloric acid aqueous solution, and was then vacuum-dried at 110 degreeC, and 0.36 g of phosphonic acid ester group introduction | transduction polymer PE-4-1 was obtained. The yield was 62%.
In the IR ^{measurement, 1056cm -1,} by the absorption peak was observed in the vicinity of 1026cm ^-1, it was confirmed that the PE-4-1 phosphonic acid ester group is introduced.
The introduction rate of the phosphonic acid ester group was calculated to be 29% by ion chromatography.

IR, ν (cm ⁻¹ , KBr disk): 3431 (w), 3065 (w), 2955 (m, C—H st), 2901 (w), 1585 (w, arC-C), 1391 (m) , 1248 (s, SiC-H), 1164 (w), 1134 (m), 1115 (m), 1056 (m, P-O-C), 1026 (s, P-O-C), 964 (m ), 837 (s, Si-C), 759 (m), 721 (m), 692 (m), 560 (m).

[Introduction of phosphonate ester group (2)]
Under an argon atmosphere, 0.5 g (1.5 mmol) of the polymer P-4 was weighed into an eggplant flask, added with 50 mL of toluene, and stirred at 100 ° C. for 15 hours to prepare a solution. To this solution were added diethyl phosphite 3.9 mL (30 mmol), tetrakistriphenylphosphine palladium 2.6 g (2.3 mmol) and dehydrated triethylamine 9 mL, and the mixture was stirred at 100 ° C. for 6 days. Thereafter, this solution was poured into n-hexane, and the resulting precipitate was purified by reprecipitation twice. The resulting precipitate was filtered off and vacuum dried at 60 ° C. for 6 hours or more. Further, this precipitate was purified by Soxhlet extraction with acetone for 4 days to obtain 0.42 g of phosphonate ester group-introduced polymer PE-4-2. The yield was 72%.
In the IR ^measurement, 1051 -1, by the absorption peak was observed in the vicinity of 1022cm ^-1, it was confirmed that the PE-4-2 phosphonic acid ester group is introduced. The introduction rate of the phosphonic acid ester group was calculated to be 48% by ion chromatography.

IR, ν (cm ⁻¹ , KBr disk): 3448 (w), 3423 (w), 2956 (w), 2901 (m), 1598 (w), 1391 (m), 1247 (s, SiC-H) , 1164 (w), 1133 (m), 1115 (s), 1051 (s, P—O—C), 1022 (s, P—O—C), 963 (s), 838 (m, Si—C) ), 760 (m), 721 (m), 654 (m), 562 (m).

[Introduction of phosphonate ester group (3)]
Under an argon atmosphere, 0.54 g (1.6 mmol) of the polymer P-4 was weighed into a container, 50 mL of toluene was added, and the mixture was stirred at 100 ° C. for 15 hours to prepare a solution. To this solution, 8.0 mL of ethanol and 3.0 mL of dehydrated triethylamine were added, 44 mg (0.2 mmol) of palladium acetate was added, 1.5 mL (11 mmol) of diethyl phosphite was further added, and the mixture was stirred at 100 ° C. for 7 days. . This solution was poured into methanol, and the resulting precipitate was purified by reprecipitation twice. The precipitate was filtered off and vacuum dried at 60 ° C. for 6 hours or more. Further, this precipitate was subjected to Soxhlet extraction with acetone to obtain 0.30 g of a phosphonic acid ester group-introduced polymer PE-4-3.
In the IR ^{measurement, 1056cm -1,} by the absorption peak was observed in the vicinity of 1027cm ^-1, it was confirmed that the PE-4-3 phosphonic acid ester group is introduced. The introduction rate of the phosphonic acid ester group was calculated to be 11% by ion chromatography.

IR, ν (cm ⁻¹ , KBr disk): 3066 (w), 2956 (m), 2899 (m), 1589 (w), 1484 (m), 1390 (m), 1249 (s, SiC-H) 1114 (s), 1056 (s, P-O-C), 1027 (s, P-O-C), 962 (m), 837 (m, Si-C), 816 (s), 756 (w ), 718 (m), 554 (w).

[Introduction of phosphonate ester group (4)]
Under an argon atmosphere, 0.33 g (1.0 mmol) of the polymer P-4 was weighed into a container, 40 mL of toluene was added, and the mixture was stirred at 100 ° C. for 15 hours to prepare a solution. To this solution, 6.0 mL of ethanol and 1.5 mL of dehydrated triethylamine were added, and then 0.34 g (1.5 mmol) of palladium acetate was added, and 0.77 mL (6.0 mmol) of diethyl phosphite was further added. Then, it stirred at 100 degreeC for 5 days. This solution was poured into methanol, and the resulting precipitate was purified by reprecipitation twice. The resulting precipitate was filtered off and vacuum dried at 60 ° C. for 6 hours or more. Further, the precipitate was Soxhlet extracted with acetone to obtain 0.44 g of a phosphonic acid ester group-introduced polymer PE-4-4. The yield was 49%.
In the IR ^{measurement, 1056cm -1,} by the absorption peak was observed in the vicinity of 1024cm ^-1, it was confirmed that the PE-4-4 phosphonic acid ester group is introduced. The introduction rate of the phosphonic acid ester group was calculated to be 27% by ion chromatography.

IR, ν (cm ⁻¹ , KBr disk): 3066 (w), 2958 (m), 1598 (w), 1485 (m), 1391 (m), 1250 (s, Si—C), 1115 (s) , 1056 (s, P-O-C), 1024 (s, P-O-C), 963 (m), 855 (s), 837 (s, Si-C), 815 (s), 757 (w ), 719 (m), 556 (w).

[Introduction of phosphonate ester group (5)]
Under an argon atmosphere, 0.33 g (1.0 mmol) of the polymer P-4 was weighed into an eggplant flask, and 40 mL of dehydrated tetrahydrofuran was added and heated to dissolve to prepare a polymer solution. After adding 1.3 mL (1.6 mol / L, 2.0 mmol) of n-butyllithium hexane solution to another eggplant flask connected to the eggplant flask with a connecting tube, the polymer solution was added thereto, and the mixture was stirred for 15 minutes. Then, 0.43 g (2.5 mmol) of diethyl chlorophosphate was added, and the mixture was stirred at room temperature for 5 days. Thereafter, this solution was poured into toluene, and the generated precipitate was purified by reprecipitation. The resulting precipitate was filtered off and vacuum dried at 60 ° C. for 6 hours or more. Furthermore, Soxhlet extraction was performed with acetone to obtain 0.29 g of a phosphonic acid ester group-introduced polymer PE-4-5. The yield at this time was 75%.
In IR measurement, it was confirmed that a phosphonate group was introduced into PE-4-5 by observing an absorption peak in the vicinity of 1034 cm ⁻¹ . The introduction rate of the phosphonate ester group was calculated to be 10% by ion chromatography.

IR, ν (cm ⁻¹ , KBr disk): 3453 (w), 3058 (w), 2956 (w), 1597 (w), 1487 (m), 1249 (s, Si—C), 1116 (w) , 1034 (m, P—O—C), 835 (m, Si—C), 755 (m), 719 (m), 691 (m), 552 (m).

[Deprotection of phosphonate ester group (1)]
Under an argon atmosphere, 0.14 mL (1.8 mmol) of dimethyl sulfide was added to a 50 mL eggplant-shaped flask and cooled in an ice bath. To this, 0.31 mL (4.8 mmol) of methanesulfonic acid was gradually added dropwise, and a toluene solution of 0.15 g of the phosphonic acid ester group-introduced polymer PE-4-1 was further added dropwise. The solution was returned to room temperature and stirred for 4 days. The obtained solution was poured into pure water, and the generated precipitate was filtered off and then vacuum dried at 110 ° C. to obtain 0.14 g of a phosphonic acid group-introduced polymer PP-4-1.
In the IR measurement, ^1056Cm -1 derived from phosphonic acid ester group, disappeared absorption peak near 1026cm ^-1, newly ^1005Cm -1, by the absorption peak was observed near 930 cm ^-1, PE-4-1 It was confirmed that the deprotection reaction of was progressed. Moreover, since the absorption peak derived from the trimethylsilyl group in the vicinity of 1248 cm ⁻¹ and 837 cm ⁻¹ also disappeared, it was confirmed that the detrimethylsilyl reaction of PE-4-1 proceeded simultaneously.

IR, ν (cm ⁻¹ , KBr disk): 3425 (m), 1641 (w, arC-C), 1600 (w), 1489 (m), 1208 (s), 1145 (w), 1005 (m, P-OH), 930 (w, P-OH), 821 (m), 779 (w), 691 (s), 556 (s).

[Deprotection reaction of phosphonate ester group (2)]
In an eggplant flask, 0.15 g of a phosphonic acid ester group-introduced polymer PE-4-1 was weighed, 100 mL of hydrobromic acid (47% by mass) was added, and the mixture was refluxed for 24 hours. Next, the polymer was filtered off, thoroughly washed with pure water, and boiled in pure water for 24 hours. Then, it was made to vacuum-dry at 110 degreeC for 6 hours or more, and 0.10 g of phosphonic acid group introduction | transduction polymer PP-4-2 was obtained. The yield at this time was 99%.
In the IR measurement, ^1056Cm -1 derived from phosphonic acid ester group, disappeared absorption peak near 1026cm ^-1, newly ^993Cm -1, by the absorption peak was observed in the vicinity of 926cm ^-1, PE-4-1 It was confirmed that the deprotection reaction of was progressed. In addition, since the absorption peak derived from the trimethylsilyl group near 1248 cm ⁻¹ and 837 cm ⁻¹ disappeared, it was confirmed that the detrimethylsilyl reaction of PE-4-1 also proceeded simultaneously.

IR, ν (cm ⁻¹ , KBr disk): 3405 (m), 3054 (w), 2387 (w), 1628 (w, arC-C), 1600 (w), 1489 (m), 1140 (s) , 1074 (w), 993 (s, P—OH), 926 (s, P—OH), 821 (m), 756 (w), 691 (s), 557 (s).

[Deprotection reaction of phosphonate ester group (3)]
Under an argon atmosphere, 0.52 g (1.3 mmol) of a phosphonic acid ester group-introduced polymer PE-4-2 was weighed into an eggplant flask, added with 10 mL of anhydrous chloroform, and stirred at room temperature to prepare a solution. Thereafter, this solution was ice-cooled, and 0.8 mL (5.6 mmol) of iodotrimethylsilane was added. The solution was returned to room temperature and stirred for 24 hours. Thereafter, a saturated aqueous solution of sodium sulfite was added and stirred, and the resulting precipitate was filtered off to obtain 0.12 g of a phosphonic acid group-introduced polymer PP-4-3. The yield at this time was 36%.
By IR measurement, ¹⁰⁵¹ -1 derived from phosphonic acid ester group, disappeared absorption peak near 1022cm ^-1, by absorption peak at around newly 994cm ^-1 was observed, deprotection of PE-4-2 It was confirmed that the reaction proceeded. In addition, since the absorption peak derived from the trimethylsilyl group in the vicinity of 1247 cm ⁻¹ and 838 cm ⁻¹ also disappeared, it was confirmed that the detrimethylsilyl reaction of PE-4-2 proceeded simultaneously.

IR, ν (cm ⁻¹ , KBr disk): 3362 (w), 1600 (w, arC-C), 1491 (m), 1138 (s), 994 (s, P—O—C), 823 (m ), 692 (s), 557 (s).

[Polymer PE-4-3 Film Formation]
0.15 g of phosphonic acid ester group-introduced polymer PE-4-3 was weighed into an eggplant flask, and 60 mL of toluene was added and dissolved by heating to prepare a polymer solution. Then, the polymer solution is cast on a glass substrate to which a polytetrafluoroethylene frame (8 cm × 8 cm × 1 cm) installed horizontally in a thermostatic bath is attached, and left to stand at room temperature for 3 days to volatilize the solvent. It was. Next, the glass substrate was immersed in methanol, and the film formed on the glass substrate was peeled off to obtain a strong self-supporting film PE-4-3 having a film thickness of 27 μm.

[Deprotection reaction of membrane PE-4-3]
Membrane PE-4-3 0.54 g was immersed in 100 mL of hydrobromic acid (47% by mass), refluxed for 24 hours, washed thoroughly with pure water, and boiled in pure water for 24 hours. did. Furthermore, it was vacuum-dried at 110 ° C. for 6 hours or more to obtain a phosphonic acid group-introduced film and a film PP-4-4.
In the IR measurement, ^1056Cm -1 derived from phosphonic acid ester group, disappeared absorption peak near 1027cm ^-1, by absorption peak at around newly 1009Cm ^-1 were observed, deprotection of film PE-4-3 It was confirmed that the reaction proceeded. In addition, since the absorption peak derived from the trimethylsilyl group in the vicinity of 1249 cm ⁻¹ and 837 cm ⁻¹ also disappeared, it was confirmed that the detrimethylsilyl reaction of the film PE-4-3 also proceeded simultaneously.

IR, ν (cm ⁻¹ , KBr disk): 3055 (m), 2924 (w), 2854 (m), 1585 (w), 1486 (m), 1441 (w), 1390 (w), 1140 (m) ), 1074 (s), 1009 (m, P—OH), 924 (m), 818 (s), 757 (m), 692 (s), 549 (s).

[Physical properties of membrane PP-4-4]
As described above, the membrane PP-4-4 obtained by performing the deprotection reaction of the membrane PE-4-3 has a film thickness of 18 μm, a moisture content of 1.7%, a swelling degree of 103%, and an ion exchange capacity of 0.48 meq. / G. The proton conductivity of this membrane at 90 ° C. and 90 RH% was 4.4 × 10 ⁻⁶ S / cm.

{Example 2}
[Synthesis of Monomer M-5]
Monomer M-5 represented by the following formula (M-5) was synthesized.

  Monomer M-5 was synthesized in the same procedure as in [Synthesis of Monomer M-4] except that 1,3-dibromobenzene was used instead of 1-bromo-4-iodobenzene. The yield at this time was 64%.

¹ H-NMR, δ (ppm, CDCl ₃ , 400 MHz): 0.3 (9H, CH ₃ × 3), 7.3 (4H, Ph), 7.5 (3H, Ph), 7.7 (1H , Ph).

IR, ν (cm ⁻¹ , KBr disk): 3022 (w, C—H st), 2953 (m, C—H st), 2894 (w), 2219 (s, —C≡C—), 1593 ( w), 1555 (w), 1468 (w), 1405 (w, arC-C), 1248 (w, arC-C), 1248 (s, Si-H), 1102 (m), 1069 (m), 842 (s, Si-C), 822 (s, Si-C), 714 (w), 680 (m), 631 (m).

GC-MS (M / Z) ^<+> : 329.

[Synthesis of Polymer P-5]
Except for using monomer M-5 instead of monomer M-4, monomer M-5 was polymerized in the same procedure as in [Synthesis of polymer P-4] to obtain polymer P-5. The yield at this time was 80%.

IR, ν (cm ⁻¹ , KBr disk): 3066 (w), 3014 (w), 2956 (m, C—H st), 2898 (w), 1591 (w, arC-C), 1560 (w) , 1470 (m), 1408 (m), 1249 (s, SiC-H), 1115 (m), 1072 (w), 838 (s, Si-C), 814 (s), 757 (m), 722 (W), 691 (w), 552 (w).

GPC: Mn = 1.0 × 10 ⁶ , Mw = 1.7 × 10 ⁶ , Mw / Mn≈1.6.

[Introduction of phosphonate ester group]
A phosphonic acid ester group-introduced polymer PE-5 was obtained in the same manner as in [Introduction of phosphonic acid ester group (4)] except that polymer P-5 was used instead of polymer P-4.
In the IR ^{measurement, 1055cm -1,} by the absorption peak was observed near 1025 cm ^-1, it was confirmed that the PE-5 phosphonic acid ester group is introduced. The introduction rate of the phosphonic acid ester group was calculated to be 13% by ion chromatography. The obtained polymer PE-5 was soluble in toluene and tetrahydrofuran.

IR, ν (cm ⁻¹ , KBr disk): 3461 (w), 2954 (m), 1470 (m), 1388 (m), 1247 (s, Si—C), 1114 (w), 1055 (w, P-O-C), 1025 (m, P-O-C), 957 (m), 837 (s, Si-C), 813 (s), 754 (w), 691 (m).

[Film formation of polymer PE-5]
0.2 g of phosphonic acid ester group-introduced polymer PE-5 was weighed into an eggplant flask, and 50 mL of toluene was added and dissolved by heating to prepare a polymer solution. Then, the polymer solution is cast on a glass substrate to which a polytetrafluoroethylene frame (8 cm × 8 cm × 1 cm) installed horizontally in a thermostatic bath is attached, and left to stand at room temperature for 3 days to volatilize the solvent. It was. Next, the whole glass substrate was immersed in methanol, and the film formed on the glass substrate was peeled off to obtain a strong self-supporting film having a film thickness of 33 μm, film PE-5.

[Deprotection reaction of membrane PE-5]
The membrane PE-5 (55 mg) was immersed in 100 mL of hydrobromic acid (47% by mass), refluxed for 24 hours, thoroughly washed with pure water, and boiled in pure water for 24 hours. Next, it was vacuum-dried at 110 ° C. for 6 hours or more to obtain a phosphonic acid group-introduced membrane, membrane PP-5.
In the IR measurement, ^1055Cm -1 derived from phosphonic acid ester group, disappeared absorption peak near 1025 cm ^-1, by the absorption peak newly around 996cm ^-1 was observed, the deprotection reaction of the film PE-5 Confirmed that it had progressed. In addition, since the absorption peaks derived from the trimethylsilyl group in the vicinity of 1247 cm ⁻¹ and 837 cm ⁻¹ disappeared, it was confirmed that the detrimethylsilyl reaction of the film PE-5 also proceeded simultaneously.

IR, ν (cm ⁻¹ , KBr disk): 3054 (m), 3019 (m), 2958 (w), 1588 (w), 1560 (m), 1491 (m), 1471 (m), 1441 (m) ), 1405 (w), 1221 (m), 1132 (m), 1072 (m), 996 (m, P-OH), 899 (m), 778 (m), 756 (m).

[Physical properties of membrane PP-5]
As described above, the membrane PP-5 obtained by performing the deprotection reaction of the membrane PE-5 had a film thickness of 25 μm, a moisture content of 8.1%, a swelling degree of 110%, and an ion exchange capacity of 0.24 meq / g. It was. The proton conductivity of this membrane at 90 ° C. and 90 RH% was 1.8 × 10 ⁻⁵ S / cm. Furthermore, no softening point was observed below 400 ° C.

{Example 3}
[Synthesis of Monomer M-6]
Monomer M-6 represented by the following formula (M-6) was synthesized.

  Monomer M-6 was synthesized in the same procedure as in [Synthesis of Monomer M-4] except that 1,4-diiodobenzene was used instead of 1-bromo-4-iodobenzene. The yield at this time was 46%.

¹ H-NMR, δ (ppm, CDCl ₃ , 400 MHz): 0.4 (9H, CH ₃ × 3), 7.4 (2H, d, Ph), 7.6 (2H, d, Ph), 7 .7 (2H, m, Ph), 7.9 (2H, d, Ph).

IR, ν (cm ⁻¹ , KBr disk): 3019 (w), 3062 (w, C—H st), 2954 (m, C—H st), 2894 (w), 2217 (s, —C≡C -), 1594 (w), 1577 (w), 1499 (m), 1477 (m), 1388 (m, arC-C), 1249 (s, SiC-H), 1141 (m), 1100 (s) , 1055 (m), 1001 (s), 855 (s, Si-C), 836 (s, Si-C), 757 (s), 714 (m), 638 (m), 514 (m).

GC-MS (M / Z) ^<+> : 375, 361, 234.

[Synthesis of Polymer M-6]
Except for using monomer M-6 instead of monomer M-4, monomer M-6 was polymerized in the same procedure as in [Synthesis of polymer P-4] to obtain polymer P-6. The yield at this time was 96%.

IR, ν (cm ⁻¹ , KBr disk): 3066 (w), 3013 (w), 2955 (m, C—H st), 2897 (w), 1580 (w, arC-C), 1480 (m) , 1386 (m), 1248 (s, SiC-H), 1114 (s), 1005 (m), 835 (s, Si-C), 815 (s, Si-C), 755 (m), 715 ( m), 551 (w).

GPC: Mn = 2.1 × 10 ⁶ , Mw = 2.4 × 10 ⁶ , Mw / Mn≈1.1.

[Introduction of phosphonate ester group]
A phosphonic acid ester group-introduced polymer PE-6 was synthesized in the same manner as in [Introduction of Phosphonic Acid Ester Group (4)], except that polymer P-6 was used instead of polymer P-4. The yield at this time was 43%.
In the IR ^{measurement, 1053cm -1,} by the absorption peak was observed in the vicinity of 1022cm ^-1, it was confirmed that the PE-6 phosphonic acid ester group is introduced. The introduction rate of the phosphonic acid ester group was calculated to be 43% by ion chromatography.

IR, ν (cm ⁻¹ , KBr disk): 3433 (W), 3059 (w), 2955 (m), 2901 (w), 1597 (w), 1438 (m), 1390 (m), 1248 (s , SiC-H), 1190 (w), 1117 (s), 1053 (m, P—O—C), 1022 (s, P—O—C), 963 (m), 838 (m, Si—C) ), 755 (m), 721 (m), 695 (m), 560 (m).

[Deprotection of phosphonate ester group (1)]
A phosphonic acid group-introduced polymer PP-6 was synthesized in the same procedure as in [Deprotection reaction of phosphonic acid ester group (3)] except that polymer PE-6 was used instead of polymer PE-4-2. . The yield at this time was 100%.
In the IR measurement, ¹⁰⁵¹ -1 derived from phosphonic acid ester group, disappeared absorption peak near 1023cm ^-1, new ^{995 cm} -1, by the absorption peak was observed in the vicinity of 921cm ^-1, prolapse PE-6 It was confirmed that the protection reaction proceeded. In addition, since the absorption peak derived from the trimethylsilyl group in the vicinity of 1248 cm ⁻¹ and 838 cm ⁻¹ also disappeared, it was confirmed that the detrimethylsilyl reaction of PE-6 proceeded simultaneously.

IR, ν (cm ⁻¹ , KBr disk): 3376 (m), 3054 (m), 2387 (w), 1634 (w, arC-C), 1597 (w), 1490 (m), 1439 (m) , 1121 (s), 995 (m, P—OH), 921 (s, P—OH), 821 (m), 724 (m), 692 (s), 556 (s).

{Example 4}
[Synthesis of Monomer M-7]
Monomer M-7 represented by the following formula (M-7) was synthesized.

  Monomer M-7 was synthesized in the same procedure as in [Synthesis of Monomer M-4] except that 1,3,5-tribromobenzene was used instead of 1-bromo-4-iodobenzene. The yield at this time was 63%.

¹ H-NMR, δ (ppm, CDCl ₃ , 400 MHz): 0.2 (9H, CH ₃ × 3), 7.4 (4H, Ph), 7.5 (1H, Ph), 7.6 (2H , Ph).

IR, ν (cm ⁻¹ , KBr disk): 3101 (w), 3071 (w, C—H st), 3020 (w), 2954 (m, C—H st), 2895 (w), 2221 (s , -C≡C-), 1593 (m), 1577 (s), 1540 (s), 1426 (m), 1400 (s, arC-C), 1247 (s, SiC-H), 1103 (s) 892 (w), 845 (s, Si-C), 820 (s, Si-C), 750 (s), 713 (m), 636 (m), 533 (m).

GC-MS (M / Z) ⁺ : 408, 392, 233.

[Synthesis of Polymer P-7]
Except for using monomer M-7 instead of monomer M-4, monomer M-7 was polymerized in the same procedure as in [Synthesis of polymer P-4] to obtain polymer P-7. The yield at this time was 95%.

^{IR, ν (cm -1, KBr} , disk): 3064 (w), 3014 (w), 2956 (m, C-H st), 2898 (w), 1576 (w, arC-C), 1546 (m ), 1401 (m), 1249 (s, SiC-H), 1109 (s), 841 (s, Si-C), 817 (s, Si-C), 748 (m), 685 (m), 552 (W).

GPC: Mn = 1.5 × 10 ⁶ , Mw = 2.0 × 10 ⁶ , Mw / Mn≈1.3.

[Introduction of phosphonate ester group]
Under an argon atmosphere, 0.51 g (1.3 mmol) of the polymer P-7 was weighed into a container, 50 mL of toluene was added, and the mixture was stirred and dissolved at 100 ° C. for 15 hours to prepare a polymer solution. To this solution, 3.3 mL (26 mmol) of diethyl phosphite, 2.3 g (2.0 mmol) of tetrakistriphenylphosphine palladium and 4.0 mL of dehydrated triethylamine were added and stirred at 100 ° C. for 7 days. Thereafter, this solution was poured into methanol, and the generated precipitate was purified by reprecipitation. The resulting precipitate was filtered off and vacuum dried at 60 ° C. for 6 hours or more. Furthermore, Soxhlet extraction was performed with acetone for 4 days to obtain 0.50 g of phosphonic acid ester group-introduced polymer PE-7. The yield at this time was 74%.
In the IR ^{measurement, 1056cm -1,} by the absorption peak was observed in the vicinity of 1027cm ^-1, the resulting polymer PE-7 phosphonic acid ester group was confirmed to have been introduced. The introduction rate of the phosphonic acid ester group was calculated to be 27% by ion chromatography.

IR, ν (cm ⁻¹ , KBr disk): 3063 (w), 2957 (w), 2902 (m), 1577 (w), 1548 (m), 1397 (m), 1252 (s, Si—C) , 1163 (w), 1133 (m), 1056 (s, P—O—C), 1027 (s, P—O—C), 962 (m), 844 (m, Si—C), 815 (m) , Si-C), 754 (w), 691 (w).

[Film formation of polymer PE-7]
0.2 g of the phosphonate ester group-introduced polymer PE-7 synthesized as described above was weighed into an eggplant flask, and 60 mL of toluene was added and dissolved by heating to prepare a polymer solution. Then, the polymer solution is cast on a glass substrate to which a polytetrafluoroethylene frame (8 cm × 8 cm × 1 cm) installed horizontally in a thermostatic bath is attached, and left to stand at room temperature for 3 days to volatilize the solvent. It was. Next, the whole glass substrate was immersed in methanol, and the film formed on the glass substrate was peeled off to obtain a strong self-supporting film having a film thickness of 48 μm, film PE-7.

[Deprotection reaction of phosphonate group-introduced membrane (membrane PE-7)]
Membrane PE-7 (0.13 g) was refluxed for 24 hours in a state of being immersed in 100 mL of hydrobromic acid (47% by mass), sufficiently washed with pure water, and further boiled in pure water for 24 hours. Vacuum-dried at 110 ° C. for 6 hours or more to obtain 0.11 g of a phosphonic acid group-introduced membrane, membrane PP-7. In the IR measurement, ^1056Cm -1 derived from phosphonic acid ester group, disappeared absorption peak near 1027cm ^-1, by absorption peak newly around 1002cm ^-1 was observed, the deprotection reaction of the membrane PE-7 Confirmed that it had progressed. In addition, since the absorption peak derived from the trimethylsilyl group in the vicinity of 1252 cm ⁻¹ and 844 cm ⁻¹ also disappeared, it was confirmed that the detrimethylsilyl reaction of the film PE-7 also proceeded simultaneously.

IR, ν (cm ⁻¹ , KBr disk): 3401 (m), 3056 (w), 2964 (w), 2925 (w), 1627 (w, arC-C), 1575 (w), 1545 (m) , 1400 (m), 1136 (m), 1105 (m), 1002 (m, P-OH), 937 (m), 758 (w), 689 (s), 529 (m).

[Physical properties of phosphonic acid group-introduced membrane PP-7]
As described above, the membrane PP-7 obtained by deprotecting the membrane PE-7 had a film thickness of 49 μm, a moisture content of 7.1%, a swelling degree of 110%, and an ion exchange capacity of 0.98 meq / g. It was. The proton conductivity of this membrane at 90 ° C. and 90 RH% was 8.1 × 10 ⁻⁴ S / cm. Furthermore, no softening point was observed below 400 ° C.

{Example 5}
[Synthesis of Monomer M-8]
Monomer M-8 represented by the following formula (M-8) was synthesized.

  Monomer M-8 was synthesized in the same procedure as in [Synthesis of Monomer M-4] except that 3,5-dibromo-1-trimethylsilylbenzene was used instead of 1-bromo-4-iodobenzene. The yield at this time was 49%.

¹ H-NMR, δ (ppm, CDCl ₃ , 400 MHz): 0.3 (9H, CH ₃ × 3), 7.3 (3H, Ph), 7.5 (3H, Ph), 7.6 ( 2H, Ph).

IR, ν (cm ⁻¹ , KBr disk): 3057 (w, C—H st), 2956 (m, C—H st), 2897 (w), 2227 (s, —C≡C—), 1599 ( w), 1576 (w), 1544 (m), 1490 (w), 1388 (w, arC-C), 1304 (w, arC-C), 1251 (s, Si-H), 1156 (m), 1129 (m), 1104 (m), 907 (m), 839 (s, Si-C), 755 (s), 687 (m).

GC-MS (M / Z) ^<+> : 329.

[Synthesis of Polymer P-8]
Except for using monomer M-8 instead of monomer M-4, monomer M-8 was polymerized in the same procedure as in [Synthesis of polymer P-4] to obtain polymer P-8. The yield at this time was 15%.

IR, ν (cm ⁻¹ , KBr disk): 3055 (w), 2957 (m, C—H st), 2899 (w), 1545 (w, arC—C), 1250 (s, SiC—H), 1132 (w), 1107 (w), 838 (s, Si-C), 755 (s), 690 (s), 623 (w).

GPC: Mn = 5.4 × 10 ⁴ , Mw = 1.2 × 10 ⁵ , Mw / Mn≈2.2.

[Introduction of phosphonate ester group]
A phosphonic acid ester group-introduced polymer PE-8 was obtained in the same procedure as in [Introduction of phosphonic acid ester group (4)] except that polymer P-8 was used instead of polymer P-4. The yield was 83%.
In the IR ^{measurement, 1056cm -1,} by the absorption peak was observed in the vicinity of 1024cm ^-1, it was confirmed that the phosphonic acid ester groups in the polymer PE-8 has been introduced. The introduction rate of the phosphonate ester group was calculated to be 13% by ion chromatography.

IR, ν (cm ⁻¹ , KBr disk): 3053 (w), 2957 (m), 2900 (w), 1630 (w), 1546 (w), 1443 (m), 1383 (m), 1249 (s , Si-C), 1135 (s), 1056 (m, P-O-C), 1024 (m, P-O-C), 955 (w), 838 (s, Si-C), 755 (w ), 691 (s).

{Example 6}
[Synthesis of Monomer M-9]
Monomer M-9 represented by the following formula (M-9) was synthesized.

  Monomer M-9 was synthesized in the same procedure as in [Synthesis of Monomer M-4] except that 3,5-dibromotoluene was used instead of 1-bromo-4-iodobenzene. The yield at this time was 61%.

¹ H-NMR, δ (ppm, Acetone-d ₆ , 400 MHz): 0.40 (9H, s, CH ₃ × 3), 2.47 (3H, s, CH ₃ ), 7.47 (1H, s , Ph), 7.53 (1H, s, Ph), 7.64 (3H, t, J = 8.0 Hz, Ph), 7.71 (2H, d, J = 8.0 Hz, Ph).

IR, ν (cm ⁻¹ , KBr disk): 3022 (w), 2955 (m), 2893 (w), 1596 (m), 1558 (m), 1444 (w), 1409 (w), 1376 (w ), 1242 (m), 1101 (m), 835 (s), 821 (s), 752 (m), 676 (m).

[Synthesis of Polymer P-9]
Except for using monomer M-9 instead of monomer M-4, monomer M-9 was polymerized in the same procedure as in [Synthesis of polymer P-4] to obtain polymer P-9. The yield at this time was 78%.

IR, ν (cm ⁻¹ , KBr disk): 3063 (w), 3012 (w), 2955 (m), 2897 (w), 1596 (m), 1565 (m), 1452 (w), 1418 (w ), 1386 (w), 1246 (s), 1112 (m), 1084 (w), 835 (s), 821 (s), 757 (m), 719 (m), 689 (m).

[Introduction of phosphonate ester group]
A phosphonic acid ester group-introduced polymer PE-9 was obtained in the same manner as in [Introduction of phosphonic acid ester group (4)], except that polymer P-9 was used instead of polymer P-4. The yield at this time was 90%.
In the IR ^{measurement, 1056cm -1,} by the absorption peak was observed in the vicinity of 1027cm ^-1, it was confirmed that the polymer PE-9 phosphonic acid ester group is introduced. The introduction rate of the phosphonic acid ester group was calculated to be 15% by ion chromatography.

IR, ν (cm ⁻¹ , KBr disk): 3063 (w), 2955 (s), 2901 (m), 1596 (w), 1565 (w), 1445 (m), 1387 (m), 1246 (s , Si—C), 1135 (w), 1115 (m), 1056 (m, P—O—C), 1027 (m, P—O—C), 959 (w), 834 (s, Si—C) ), 813 (m), 756 (w), 693 (s).

[Film formation of polymer PE-9]
0.2 g of the phosphonic acid ester group-introduced polymer PE-9 synthesized as described above was weighed into an eggplant flask, and 60 mL of toluene was added and dissolved by heating to prepare a polymer solution. Then, the polymer solution is cast on a glass substrate to which a polytetrafluoroethylene frame (8 cm × 8 cm × 1 cm) installed horizontally in a thermostatic bath is attached, and left to stand at room temperature for 3 days to volatilize the solvent. It was. Next, the film formed by immersing the glass substrate in methanol was peeled off to obtain a strong self-supporting film having a film thickness of 26 μm, film PE-9.

[Deprotection of phosphonate ester group-introduced membrane (membrane PE-9)]
After 0.067 g of membrane PE-9 was immersed in 100 mL of hydrobromic acid (47% by mass) for 24 hours, it was thoroughly washed with pure water and then boiled in pure water for 24 hours. Next, it was vacuum-dried at 110 ° C. for 6 hours or more to obtain a phosphonic acid group-introduced membrane, membrane PP-9.
In the IR measurement, ^1056Cm -1 derived from phosphonic acid ester group, disappeared absorption peak near 1027cm ^-1, by absorption peak at around newly 991cm ^-1 was observed, the deprotection reaction of the film PE-9 Confirmed that it had progressed. In addition, since the absorption peak derived from the trimethylsilyl group in the vicinity of 1252 cm ⁻¹ and 844 cm ⁻¹ also disappeared, it was confirmed that the detrimethylsilyl reaction of the film PE-9 also proceeded simultaneously.

IR, ν (cm ⁻¹ , KBr disk): 3052 (w), 2962 (w), 2922 (w), 2853 (w), 1596 (m, arC-C), 1563 (m), 1490 (m) , 1441 (m), 1262 (s), 1137 (m), 1104 (m), 1072 (m), 1012 (s), 991 (m, P-OH), 945 (m), 845 (m), 822 (m), 756 (m).

[Physical properties of phosphonic acid group-introduced membrane PP-9]
As described above, the membrane PP-9 obtained by performing the deprotection reaction of the membrane PE-9 had a film thickness of 32 μm, a moisture content of 7.1%, a swelling degree of 103%, and an ion exchange capacity of 0.50 meq / g. It was. The proton conductivity of this membrane at 90 ° C. and 90 RH% was 2.6 × 10 ⁻⁵ S / cm. Furthermore, no softening point was observed below 400 ° C.

{Example 7}
[Synthesis of phosphonic acid group and sulfonic acid group-introduced membrane PPS-1]
In a 500 mL beaker, 80 mL of concentrated sulfuric acid (97% by mass) and 20 mL of ethyl acetate were weighed and mixed, and 49 mg of the phosphonate ester group-introduced membrane PE-7 was immersed therein and gently stirred at 60 ° C. for 3 hours. did. The membrane was taken out, washed with water, and boiled with pure water for 2 hours. Then, it vacuum-dried at 110 degreeC for 16 hours. Thereafter, the membrane was refluxed for 72 hours in a state immersed in 100 mL of hydrobromic acid (47% by mass), then sufficiently washed with pure water, and further boiled in pure water for 24 hours. Next, it was vacuum-dried at 110 ° C. for 6 hours or more to obtain a phosphonic acid group and sulfonic acid group-introduced membrane PPS-1.
In the IR measurement, ^1056Cm -1 derived from phosphonic acid ester group, disappeared absorption peak near 1027cm ^-1, by absorption peak newly around 966cm ^-1 was observed, the deprotection reaction of the membrane PE-7 Confirmed that it had progressed. In addition, since the absorption peak derived from the trimethylsilyl group in the vicinity of 1249 cm ⁻¹ and 1056 cm ⁻¹ disappeared, it was confirmed that the detrimethylsilyl reaction of the film PE-7 also proceeded simultaneously. Furthermore, since an absorption peak derived from a sulfonic acid group was observed in the vicinity of 1024 cm ⁻¹ , it was also confirmed that a sulfonic acid group was introduced into the membrane PPS-1.

IR, ν (cm ⁻¹ , KBr disk): 3420 (w), 3056 (w), 2982 (m), 2926 (m), 1576 (w), 1546 (s), 1489 (w), 1443 (m) ), 1397 (m), 1226 (s), 1163 (m), 1134 (m), 1048 (s), 1024 (s, SO ₃ H), 966 (s, P—OH), 758 (m), 690 (s), 566 (m).

[Physical properties of membrane PPS-1]
The phosphonic acid group and sulfonic acid group-introduced membrane PPS-1 produced as described above has a film thickness of 44 μm, an ion exchange capacity of 1.4 meq / g, a moisture content of 19%, a swelling degree of 118%, and a proton conductivity of 9.7 ×. 10 ⁻³ S / cm (90 ° C., RH 90%). Furthermore, no softening point was observed below 400 ° C.

{Example 8}
[Synthesis of phosphonic acid group and sulfonic acid group-introduced membrane PPS-2]
[Phosphonic acid group and sulfonic acid group-introduced membrane PPS] except that the phosphonic acid ester group-introduced membrane PE-9 produced in Example 6 was used and that the reflux time with hydrobromic acid was 96 hours. The phosphonic acid group and sulfonic acid group-introduced membrane PPS-2 was obtained in the same procedure as in the synthesis of -1.
In the IR measurement, ^1056Cm -1 derived from phosphonic acid ester group, disappeared absorption peak near 1027cm ^-1, by absorption peak at around newly 963cm ^-1 was observed, phosphonic acid ester group introduced film PE-9 It was confirmed that the deprotection reaction of was progressed. In addition, since the absorption peak derived from the trimethylsilyl group in the vicinity of 1249 cm ⁻¹ and 1056 cm ⁻¹ disappeared, it was confirmed that the detrimethylsilyl reaction of the phosphonate ester group-introduced film PE-9 also proceeded simultaneously. Furthermore, since an absorption peak derived from a sulfonic acid group was observed in the vicinity of 1024 cm ⁻¹ , it was also confirmed that a sulfonic acid group was introduced into the membrane PPS-2.

IR, ν (cm ⁻¹ , KBr disk): 3062 (w), 2955 (s), 2899 (m), 1576 (w), 1546 (s), 1421 (w), 1400 (m), 1247 (s ), 1161 (w), 1111 (m), 1048 (s), 1024 (s, SO ₃ H), 963 (s, P—OH), 835 (s), 814 (s), 745 (s).

[Physical properties of membrane SPP-2]
The phosphonic acid group and sulfonic acid group-introduced membrane SPP-2 produced as described above has a film thickness of 20 μm, an ion exchange capacity of 1.5 meq / g, a water content of 20%, a swelling degree of 118%, and a proton conductivity of 1.2 ×. 10 ⁻² S / cm (90 ° C., RH 90%). Furthermore, no softening point was observed below 400 ° C.

{Example 9}
[Synthesis of Imidazole, Phosphonic Acid Group, and Sulfonic Acid Group Introduced Membrane IPPS-1]
83 mg (1.2 mmol) of imidazole was dissolved in 100 mL of pure water, and 51 mg of the membrane PPS-1 prepared in Example 7 was immersed in the solution and stirred for 24 hours. Thereafter, the membrane was washed with pure water and vacuum dried at 110 ° C. for 16 hours to obtain an imidazole, phosphonic acid group, and sulfonic acid group-introduced membrane IPPS-1.
In IR measurement, since a peak derived from imidazole was observed in the vicinity of 1627 cm ⁻¹ , it was confirmed that imidazole was introduced into the membrane IPPS-1. The FT-IR spectrum is shown below.

IR, ν (cm ⁻¹ , KBr disk): 3353 (w), 3054 (w), 2853 (w), 1627 (m, C = N), 1575 (w), 1545 (s), 1488 (m) , 1441 (s), 1400 (s), 1132 (m), 1059 (m), 1036 (m, SO ₃ H), 1007 (s, P—OH), 990 (s), 909 (s), 870 (M), 758 (m), 741 (s).

[Physical properties of membrane IPPS-1]
The imidazole, phosphonic acid group, and sulfonic acid group-introduced membrane IPPS-1 produced as described above has a film thickness of 30 μm, an ion exchange capacity of 1.3 meq / g, a moisture content of 21%, a swelling degree of 118%, and a proton conductivity of 2. It was 2 × 10 ⁻⁵ S / cm (90 ° C., RH 50%). Furthermore, no softening point was observed below 400 ° C.

[Fenton test results]
As samples, Nafion (registered trademark) 115 which is a commercially available electrolyte membrane, the membrane PS-3 produced in Comparative Example 3, the membrane PP-7 produced in Example 4, and the membrane PPS-1 produced in Example 7 were used. The Fenton test was performed on each membrane, and the mass change rate before and after the Fenton test and the proton conductivity (measured at 90 ° C. and 90 RH%) were measured and compared. The results are shown in Table 1.

  As shown in Table 1, the membranes of Examples 4 and 7 which are substituted polyacetylene membranes having phosphonic acid groups or phosphonic acid groups and sulfonic acid groups are more resistant to oxidation than the commercially available products and Comparative Example 3 membranes. Excellent proton resistance and radical resistance and high proton conductivity. Therefore, according to the present invention, a solid electrolyte having excellent oxidation resistance and radical resistance, high proton conductivity, sufficient heat resistance, low swelling, and sufficient mechanical strength. And its membrane can be obtained. In addition, if the heterocyclic compound is impregnated, an electrolyte membrane showing good proton conductivity even at high temperature and low humidity can be obtained. Furthermore, an electrolyte membrane that does not contain fluorine and can be incinerated can be provided.

Claims (12)

  A substituted polyacetylene having a side chain containing a phosphonic acid group in the main chain composed of polyacetylene.   A substituted polyacetylene having a side chain containing a phosphonic acid group and a side chain containing a sulfonic acid group in the main chain made of polyacetylene. Following formula (1)

[However, in the formula (1), a part or all of R ^{1 to} R ⁶ is a phosphonic acid group, and the rest are H, Br, Cl, I, a silicon-containing substituent, a hydroxyl group, a straight chain having 1 to 6 carbon atoms. Any one selected from the group consisting of a chain or branched alkyl group or an alkoxy group, a phenoxy group, and a sulfonic acid group. ] The substituted polyacetylene which has a repeating unit represented by these. In the formula (1), R ¹ , R ³ and R ⁵ are H, R ² is a silicon-containing substituent or H, and one or both of R ⁴ and R ⁶ are phosphonic acid groups, The substituted polyacetylene according to claim 3, wherein the remainder is any one selected from the group consisting of H, a methyl group, a sulfonic acid group, Br, Cl, and I. A part of R ^{1 to} R ³ in the formula (1) is a sulfonic acid group, the rest is H, a part or all of R ^{4 to} R ⁶ is a phosphonic acid group, and the rest is H, a methyl group 4. The substituted polyacetylene according to claim 3, which is any one selected from the group consisting of B, Br, Cl and I. 5. At least one of R ^{1 to} R ³ in the formula (1) is a silicon-containing substituent, the rest is H, a part or all of R ^{4 to} R ⁶ is a phosphonic acid group, and the rest is H. A substituted polyacetylene having a phosphonic acid group and a sulfonic acid group in the side chain is obtained by sulfonating a substituted polyacetylene selected from the group consisting of a methyl group, Br, Cl, and I with a sulfonating agent. A process for producing a substituted polyacetylene.   The electrolyte membrane which consists of substituted polyacetylene of any one of Claims 1-5.   An electrolyte membrane obtained by the method for producing a substituted polyacetylene according to claim 6 and formed into a membrane shape, wherein the distribution of sulfonic acid groups in the membrane is uniform in the film thickness direction.   The electrolyte membrane according to claim 7 or 8, wherein the membrane is impregnated with imidazole, benzimidazole, triazole, pyrazole or a derivative thereof.   An electrolyte membrane / electrode assembly obtained by providing an electrode on the electrolyte membrane according to any one of claims 7 to 9, or a composite membrane containing the electrolyte membrane.   An electrochemical device comprising the electrolyte membrane / electrode assembly according to claim 10.   A fuel cell comprising the electrolyte membrane / electrode assembly according to claim 10.