JP2012172033A - Proton conductive polymer and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a proton conductive polymer which is used as an electrolyte membrane for PEFC operating under the conditions of a medium temperature region and low humidification, and a method for producing the same.SOLUTION: It has been found that the two kinds of functional groups of a sulfonic acid group and a phosphonic acid group are introduced into a polymer skeleton of polyether sulfone or polyether ether ketone, thus an electrolyte membrane showing excellent proton conducting performance can be obtained even under higher temperature-lower humidification conditions than the conventional PEFC operation conditions dependent on the humidification of gas.

Description

  The present invention relates to a proton conductive polymer as an electrolyte material used in fuel cells and the like, and an industrial production method thereof.

  A normal polymer electrolyte fuel cell (PEFC) operates at a power generation cell operating temperature of about 80 ° C. As a gas supplied to the power generation cell, a reformed gas containing hydrogen to the anode (fuel electrode), cathode (air) It is common to introduce air as an oxidant into the pole). At this time, the electrolyte membrane separating the anode and the cathode is generated by oxidizing the hydrogen introduced into the anode on the electrode while having a function of separating the gas introduced into both electrodes so as not to mix (gas barrier property). Protons are transported to the cathode side and simultaneously serve for the reaction of reducing oxygen in the air on the cathode electrode (proton conductivity). In the conventional PEFC, the perfluorohydrocarbon polymer having a sulfonic acid group in the side chain, represented by DuPont's Nafion (registered trademark), is used as the material for this electrolyte membrane. It has been suitably used as a material having performance.

  However, this sulfonic acid group-containing perfluorohydrocarbon polymer has a mechanism in which sulfonic acid groups involve water molecules in protons and conduct protons as hydronium ions, so it is necessary to humidify the supplied gas to near 100% relative humidity. There is. Also, due to this requirement, it was theoretically difficult to operate at a cell temperature of 100 ° C. or higher. In addition, fluorocarbons adjacent to sulfonic acid groups, fluorohydrocarbon main chains and side chains, and branching points are used as by-products in power generation cells triggered by carbon atoms that are not fluorinated and carboxyl groups that remain in the manufacturing process. It has recently become clear that it is gradually decomposed by active species such as OH radicals. For this reason, improvement has come to be demanded from the viewpoint of long-term use of the fuel cell and robustness of operation under a wide range of cell temperatures and gas humidification conditions.

  Another improvement required for the PEFC power generation cell is to maintain a stable power generation state even when the power generation cell operating temperature rises. This is because, in particular, in-vehicle applications, it is inevitable that the cell is temporarily heated to a high temperature because the cooling during power generation cannot catch up, and the cell material itself is required to have high temperature resistance. This is because increasing the high-temperature resistance of the cell leads to great merit in downsizing and simplification. On the other hand, in the stationary fuel cell system, the influence of CO in the reformed gas supplied to the anode electrode of the power generation cell on the Pt electrode can be reduced by increasing the temperature, and the temperature of the heat recovery water is increased. The advantage of increasing the cell operating temperature is praised, such as the fact that waste heat recovery mechanisms such as hot water storage tanks can be reduced in size and weight.

  In order to overcome these problems in the current PEFC, a cell capable of reducing the humidification mechanism of the gas supplied to the cell and capable of generating power stably even when the cell operating temperature is increased is required. In order to realize this cell, it is essential to improve the solid polymer electrolyte that governs the cell operating temperature condition and the humidification condition.

  In a temperature range of 100 ° C. or more and 300 ° C. or less (hereinafter referred to as an intermediate temperature range. A polymer electrolyte fuel cell in which the highest operating cell temperature reaches this temperature range is referred to as an “intermediate temperature cell”). As a material for the electrolyte membrane to operate, it is essential that the proton is a substance that can be conducted in the proton state without passing through the hydronium ion accompanied by water molecules. The phosphoric acid which has been used for the fuel cell is mentioned. An electrolyte membrane in which a basic polymer such as polybenzimidazole (PBI) is doped with phosphoric acid is also known, and this phosphoric acid-PBI membrane is generally used for a medium temperature cell.

Japanese National Patent Publication No. 11-503262

  In systems using liquid phosphoric acid or phosphoric acid-PBI, electrolyte performance is impaired due to outflow of phosphoric acid, problems of system corrosion due to outflowed phosphoric acid, Pt when using Pt-based electrodes There were many problems peculiar to phosphoric acid system, such as low electrode performance due to the specific adsorption of phosphoric acid on the surface.

  The present invention has been made in view of these problems, and the object thereof is a medium temperature / low humidity humidification which has been a weak point of sulfone group-containing perfluorohydrocarbon polymers that have been used exclusively in conventional polymer electrolyte fuel cells. An object of the present invention is to provide a proton conducting polymer having high proton conducting performance even under conditions and a method for producing the same.

The first aspect of the present invention is a proton conducting polymer. The proton conductive polymer is represented by the following general formula (1).
− {O−R ¹ (X) _l −L ¹ −R ¹ (X) _l −O−R ² (Y) _m −L ² −R ² (Y) _m −} _n (1)
(1) In the formula, R ¹ (X) _l represents a benzene ring in which the para-position is the polymer main chain, and at least a part of the ortho-position to the O atom bond is substituted by the substituent X Indicates.
X represents —P (═O) (OH) ₂ or —CH ₂ —P (═O) (OH) ₂ .
l is the average number of substituents per benzene ring, and 0 <l ≦ 2.
L ¹ is a linking group and represents a bond selected from — (single bond), —CH ₂ —, —CF ₂ —, —C (CH ₃ ) ₂ —, and —C (CF ₃ ) ₂ —.
R ² (Y) _m represents a benzene ring whose para-position is the polymer main chain, and that at least a part of the ortho-position with respect to the O atom bond is substituted with the substituent Y.
Y denotes a -SO ₃ H.
m is the average number of substituents per benzene ring, and 0 <m ≦ 2.
L ² is a linking group and represents a bond selected from —C (═O) — and —SO ₂ —.
n represents the average number of repeating units of the polymer, and the average value is determined by the weight average molecular weight determined separately.

The second aspect of the present invention is a proton conducting polymer. The proton conductive polymer is represented by the following general formula (2).
− {O−R ¹ −C (CH ₃ ) (R ³ (X) _k ) −R ¹ −O−R ² (Y) _m −L ² −R ² (Y) _m −} _n (2)
(2) In the formula, R ¹ represents a para-substituted benzene ring.
R ³ (X) ₁ represents a benzene ring in which at least a part of the 3, 4, and 5 positions with respect to the bond with the C atom is substituted with the substituent X.
X represents —P (═O) (OH) ₂ or —CH ₂ —P (═O) (OH) ₂ .
l is the average number of substituents per benzene ring, and 0 <l ≦ 3.
R ³ (Y) _m represents a benzene ring in which the para position is the polymer main chain, and indicates that at least a part of the ortho position with respect to the O atom bond is substituted with the substituent Y.
Y denotes a -SO ₃ H.
m is the average number of substituents per benzene ring, and 0 <m ≦ 2.
L ² is a linking group and represents a bond selected from —C (═O) — and —SO ₂ —.
n represents the average number of repeating units of the polymer, and the average value is determined by the weight average molecular weight determined separately.

A third aspect of the present invention is a method for producing a proton conductive polymer. The method for producing the proton conductive polymer is represented by the general formula (1) by a reaction between the aromatic diol represented by the general formula (3) and the aromatic dihalide or dinitro compound represented by the general formula (4). To obtain a proton conducting polymer.
HO-R ¹ (X) _l -L ¹ -R ¹ (X) _l -OH (3)
Z−R ² (Y) _m −L ² −R ² (Y) _m −Z (4)
(3) In the formula, R ¹ (X) _l represents a benzene ring whose para-position is the polymer main chain, and that at least a part of the ortho-position to the OH group is substituted by the substituent X. Show.
X represents —P (═O) (OH) ₂ or —CH ₂ —P (═O) (OH) ₂ . In the polymer synthesis reaction, these are alkali salts, ammonium salts, amine salts of Na, K, NH ₄ , NR _{4 and the} like (R is H or an alkyl group), ester compounds such as Me and Et, and partial ester compounds. May be.
l is the average number of substituents per benzene ring, and 0 <l ≦ 2. A raw material having a plurality of substitution numbers may be used as the composition.
L ¹ is a linking group and represents a bond selected from — (single bond), —CH ₂ —, —CF ₂ —, —C (CH ₃ ) ₂ —, and —C (CF ₃ ) ₂ —. Also for these, a compound having a plurality of bonding groups may be used as a composition.
(4) In the formula, R ² (Y) _m represents a benzene ring in which the para position is the polymer main chain, and at least a part of the ortho position with respect to the O atom bond is substituted by the substituent Y. Indicates.
Y denotes a -SO ₃ H. In the polymer synthesis reaction, these may be alkali salts, ammonium salts, or amine salts of Na, K, NH ₄ , NR _{4 and the} like (R is H or an alkyl group).
m is the average number of substituents per benzene ring, and 0 <m ≦ 2. A raw material having a plurality of substitution numbers may be used as the composition.
L ² is a linking group and represents a bond selected from —C (═O) — and —SO ₂ —.
Z represents -F, -Cl, a terminal group selected from -NO _2.

A fourth aspect of the present invention is a method for producing a proton conductive polymer. The proton conductive polymer is produced by reacting the aromatic diol represented by the general formula (6) with the aromatic dihalide or dinitro compound represented by the general formula (4) to obtain a polymer. The polymer obtained is characterized in that a Br group is introduced by a Br agent and then the Br group is reacted with a trivalent phosphorus compound to obtain a proton conductive polymer represented by the general formula (1).
HO-R ¹ (Me) _l -L ¹ -R ¹ (Me) _l -OH (6)
(6) In the formula, R ¹ (Me) _l represents a benzene ring in which the para-position is the polymer main chain, and all the ortho-positions to the OH group are H, or a part or all of them are Me groups. Show.
l is the average number of Me groups per benzene ring, and 0 ≦ l ≦ 2. A raw material having a plurality of substitution numbers may be used as the composition.
L ¹ is a linking group and represents a bond selected from — (single bond), —CH ₂ —, —CF ₂ —, —C (CH ₃ ) ₂ —, and —C (CF ₃ ) ₂ —. Also for these, a compound having a plurality of bonding groups may be used as a composition.

A fifth aspect of the present invention is a method for producing a proton conductive polymer. The proton conductive polymer is produced by reacting the aromatic diol represented by the general formula (7) and the aromatic dihalide or dinitro compound represented by the general formula (4) to obtain a polymer. A proton conductive polymer represented by the general formula (2) is obtained by reacting a Br group remaining in the obtained polymer with a trivalent phosphorus compound.
_{^{HO-R 1 -C (CH 3}} ) (R 3 (Br) k) -R 1 -OH (7)
(7) In the formula, R ¹ represents a para-substituted benzene ring.
R ³ (Br) ₁ represents a benzene ring in which at least a part of the 3, 4, and 5 positions with respect to the bond with the C atom is substituted with Br.
k is the average number of substituents per benzene ring and takes a value between 0.01 and 3. A raw material having a plurality of substitution numbers may be used as the composition.
L ¹ is a linking group and represents a bond selected from — (single bond), —CH ₂ —, —CF ₂ —, —C (CH ₃ ) ₂ —, and —C (CF ₃ ) ₂ —. Also for these, a compound having a plurality of bonding groups may be used as a composition.

  ADVANTAGE OF THE INVENTION According to this invention, the proton conductive polymer which has a high proton-conducting performance also on medium temperature and low humidification conditions is provided.

It is a disassembled perspective view which shows schematic structure of the basic cell used for the measurement of proton-conducting performance.

  Hereinafter, embodiments of the present invention will be described in detail.

(Chemical structure of polymer)
The proton conductive polymer according to the embodiment of the present invention is represented by the following general formula (1) or (2).
− {O−R ¹ (X) _l −L ¹ −R ¹ (X) _l −O−R ² (Y) _m −L ² −R ² (Y) _m −} _n (1)
− {O−R ¹ −C (CH ₃ ) (R ³ (X) _k ) −R ¹ −O−R ² (Y) _m −L ² −R ² (Y) _m −} _n (2)
However, R ^1, R ¹ (X) _l represents a benzene ring para position is the polymer backbone, the general formula (1) in the R ¹ (X) _l is ortho least a relative O atom bonds The part is substituted by the substituent X.
X represents —P (═O) (OH) ₂ or —CH ₂ —P (═O) (OH) ₂ .
l is the average number of substituents per benzene ring, and 0 <l ≦ 2.
L ¹ is a linking group and represents a bond selected from — (single bond), —CH ₂ —, —CF ₂ —, —C (CH ₃ ) ₂ —, and —C (CF ₃ ) ₂ —.
R ² (Y) _m represents a benzene ring whose para-position is the polymer main chain, and that at least a part of the ortho-position with respect to the O atom bond is substituted with the substituent Y.
Y denotes a -SO ₃ H.
m is the average number of substituents per benzene ring, and 0 <m ≦ 2.
L ² is a linking group and represents a bond selected from —C (═O) — and —SO ₂ —.
n represents the average number of repeating units of the polymer, and the average value is determined by the weight average molecular weight determined separately.
R ³ (X) ₁ in the general formula (2) represents a benzene ring in which at least a part of the 3, 4, and 5 positions with respect to the bond with the C atom is substituted with the substituent X.
k is the average number of substituents per benzene ring, and 0 <l ≦ 3.

(Polymer skeleton formation)
In the present embodiment, the proton conductive polymer has its basic skeleton formed by an ether bond forming reaction in the presence of a base of an aromatic diol and an aromatic dihalide. At this time, among the two types of functional groups (sulfonic acid group and phosphonic acid group) that finally remain in the polymer, the sulfonic acid group is introduced into the aromatic dihalide at the raw material monomer stage, and if necessary, Na salt, It is used for polymer formation reaction in the state of K salt. On the other hand, the phosphonic acid group is introduced to the aromatic diol side, but in the same manner as the sulfonic acid group, a monomer previously introduced in the form of phosphonic acid, phosphonate, phosphonic acid ester or the like is used. However, it may be introduced into phosphonic acid using a functional group introduction or conversion reaction after the formation of the polymer main chain.

(Basic preparation method)
Hereinafter, typical synthesis means will be described with respect to the polymer formation reaction between various forms of aromatic diols and aromatic dihalides in the present invention. Specific aromatic diol / aromatic dihalide combinations to obtain the final polymer structure are described below.

  In the present invention, about 1 mol of aromatic dihalide is used per 1 mol of aromatic diol. When a skeleton such as PES or PEEK is formed by a condensation reaction by forming an ether bond, the diol component and the dihalide component are generally carried out in the vicinity of an equimolar amount, but this molar ratio is 1: The vicinity of 1 is preferable, and the dihalide molar ratio to the diol is preferably in the range of 0.9 to 1.1. There is a concern that a polymer having a sufficient molecular weight cannot be obtained at a charge amount outside this range.

  As the dihalide, generally fluoride or chloride is used. It is also known that not only halides but also nitro compounds can react. In the present invention, fluoride and chloride are preferably used, and a high molecular weight polymer is easily obtained particularly when fluoride is used.

  In the polymerization reaction by ether bond formation, a base for dehydration condensation from these raw materials is used. As the base, alkali carbonates or alkali hydroxides such as potassium carbonate, sodium carbonate, sodium hydroxide and potassium hydroxide are preferably used. The amount of these bases used is usually in the range of 2 to 10 times, preferably 2 to 4 times the number of moles of the aromatic diol when a divalent base such as potassium carbonate is taken as an example. If a base exceeding 10 times is used, the amount of insoluble matter in the reaction system increases and the polymer yield per reactor decreases, which is industrially undesirable. If the base is less than 2 times, sufficient bond formation reaction proceeds. The polymer molecular weight tends not to increase. However, the sulfonic acid group introduced into the aromatic dihalide must be previously neutralized with an alkali salt or the like, and the range does not include the amount of base necessary for this neutralization. Similarly, when a phosphonic acid group is introduced into the diol in advance, it is necessary to neutralize the phosphonic acid with an alkali salt or the like, and this amount is not included in the range.

  These raw material compounds are put into a reactor such as a flask, and a solvent is added to partially or completely dissolve the organic monomer. Since the base component is often insoluble, it is suspended. As the solvent, polar solvents such as N-methylpyrrolidone (NMP), N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO) are preferably used. Further, water may be added to these solvents. These solvents are used in such an amount that the weight of a reactant (aromatic diol, aromatic dihalide, base) other than the solvent with respect to the total weight after addition of the solvent is 3 to 80%, preferably 5 to 60%. When the amount of the solvent is less than 3%, the proportion of the reactants in the reactor is relatively lowered, and the yield to the reactor is lowered, which is not industrial. When the amount of the solvent exceeds 80%, the stirring becomes difficult due to the undissolved solid content, and the resulting polymer is precipitated, which increases the non-uniformity of the reaction system.

  Polymer synthesis is performed by raising the reaction temperature while stirring the reactor into which these reactants and solvent are introduced with a mechanical stirrer or the like. The reaction temperature depends on the reactivity of the aromatic diol / aromatic dihalide raw material to be used and the conditions such as the base, solvent and concentration used, but cannot be generally stated, but is usually in the range of 100 to 300 ° C, preferably 120 to 250 ° C. Done in If the temperature is lower than 100 ° C, it is difficult to distill off the water produced as a by-product, and the progress of the reaction may be significantly slowed. If it exceeds 300 ° C, side reactions such as elimination of sulfonic acid functional groups may occur. There is a risk of progress, and neither condition is preferred.

  In addition, in order to more efficiently distill off the water generated in the early stage of the reaction more efficiently using a Dean-Stark trap, it may be preferable to add a solvent azeotropically with water such as toluene in addition to the above solvent. In this case, a method in which the reaction is first carried out in the vicinity of the azeotropic temperature of toluene and water, and after the water has been distilled off, is preferably used to raise the reaction temperature.

  Although the reaction time varies depending on the reactivity of the monomer used and the final polymer molecular weight, it cannot be generally stated, but is usually in the range of 30 minutes to 120 hours, preferably 2 hours to 72 hours. If it is shorter than 30 minutes, the condensation reaction may not proceed sufficiently, and only a low molecular weight polymer may be obtained, and conditions exceeding 120 hours result in low productivity and low industrial utility value. This is also not preferable. The progress of the reaction can be traced as the inherent viscosity (ηinh) or converted weight average molecular weight (Mw) of the polymer by means such as viscosity measurement of the reaction solution or gel permeation chromatography (GPC).

  The step of taking out the polymer from the reaction solution thus obtained will be described. In the reaction solution after completion of the reaction, the polymer component is often dissolved in a solvent and the excess base component is suspended, and it is necessary to extract only the polymer therefrom. First, when there is an insoluble matter in the reaction solution, it is separated by a filter paper, a filter cloth, a centrifugal sedimentation method or the like, and isolated as a solution containing a polymer. After concentration of this to obtain a crude polymer, if a base component or the like remains, hot water or the like is added and stirred for removal. Alternatively, a method in which a polymer solution is dropped into a poor solvent such as water, methanol, ethanol or a mixture thereof to reprecipitate the polymer is also used. The obtained polymer precipitate can be heated or dried under reduced pressure heating conditions to obtain a semi-solid polymer in the form of powder, flakes or partially agglomerated.

(Detailed synthesis method 1: Reaction using phosphonic acid-introduced aromatic diol)
By reacting an aromatic diol represented by the following general formula (3) with an aromatic dihalide or dinitro compound represented by the general formula (4), a proton conductive polymer of the general formula (1) can be obtained. .
HO-R ¹ (X) _l -L ¹ -R ¹ (X) _l -OH (3)
Z−R ² (Y) _m −L ² −R ² (Y) _m −Z (4)
However, R ¹ (X) ₁ represents a benzene ring in which the para position is the polymer main chain, and indicates that at least a part of the ortho position with respect to the OH group is substituted with the substituent X. X represents —P (═O) (OH) ₂ or —CH ₂ —P (═O) (OH) ₂ . In the polymer synthesis reaction, these are alkali salts, ammonium salts, amine salts of Na, K, NH ₄ , NR _{4 and the} like (R is H or an alkyl group), ester compounds such as Me and Et, and partial ester compounds. May be.
l is the average number of substituents per benzene ring, and 0 <l ≦ 2. A raw material having a plurality of substitution numbers may be used as the composition.
L ¹ is a linking group and represents a bond selected from — (single bond), —CH ₂ —, —CF ₂ —, —C (CH ₃ ) ₂ —, and —C (CF ₃ ) ₂ —. Also for these, a compound having a plurality of bonding groups may be used as a composition.
R ² (Y) _m represents a benzene ring whose para-position is the polymer main chain, and that at least a part of the ortho-position with respect to the O atom bond is substituted with the substituent Y.
Y denotes a -SO ₃ H. In the polymer synthesis reaction, these may be alkali salts, ammonium salts, or amine salts of Na, K, NH ₄ , NR _{4 and the} like (R is H or an alkyl group).
m is the average number of substituents per benzene ring, and 0 <m ≦ 2. A raw material having a plurality of substitution numbers may be used as the composition.
L ² is a linking group and represents a bond selected from —C (═O) — and —SO ₂ —.
Z represents -F, -Cl, a terminal group selected from -NO _2.

  Among the monomers that satisfy these requirements, the aromatic diol of the general formula (3) is a disubstituted bisphenol A compound in which phosphonic acid is introduced at the 2 and 2 'positions, and at the 2, 6, 2', and 6 'positions. Preferred examples include a 4-substituted bisphenol A compound into which a phosphonic acid group is introduced. As the aromatic dihalide of the general formula (4), 4,4 ′ difluorodiphenylsulfone introduced with a sulfonic acid sodium salt at the 3,3 ′ position, and 4,4 ′ difluorodiphenylsulfone introduced with a sulfonic acid sodium salt at the 3,3 ′ position, Preferred examples include 4 ′ difluorobenzophenone.

  Polymer synthesis is performed using the above aromatic diol and aromatic dihalide according to the basic preparation method described above. It is desirable that the sulfonic acid-introduced aromatic dihalide is converted into Na salt or K salt in advance and sufficiently dried before being subjected to the reaction. Similarly, the phosphonic acid-introduced aromatic diol may be used as a Na salt or a K salt. In this regard, the reaction is carried out in the state of a free phosphonic acid compound, and an excess of base is added to the alkali in the system. It may be used as a salt.

  In the sulfonic acid / phosphonic acid-introduced polymer thus obtained, the functional groups of the sulfonic acid and phosphonic acid are alkali salts immediately after the synthesis of the polymer. After neutralization, it is necessary to regenerate the organic acid by washing the alkali component by a method such as washing with water.

(Detailed synthesis method 2: Reaction 1 using bromo group-introduced aromatic diol)
Br group remaining in the polymer obtained by reacting the aromatic diol represented by the general formula (5) with the aromatic dihalide or dinitro compound represented by the general formula (4) to obtain a polymer. Is reacted with a trivalent phosphorus compound to obtain a proton conductive polymer represented by the general formula (1).
HO-R ¹ (W) _l -L ¹ -R ¹ (X) _l -OH (5)
However, R ¹ (W) ₁ represents a benzene ring in which the para position is a polymer main chain, and indicates that at least a part of the ortho position with respect to the OH group is substituted by the substituent W.
W represents —Br or —CH ₂ —Br.
l is the average number of substituents per benzene ring, and 0 <l ≦ 2. A raw material having a plurality of substitution numbers may be used as the composition.
L ¹ is a linking group and represents a bond selected from — (single bond), —CH ₂ —, —CF ₂ —, —C (CH ₃ ) ₂ —, and —C (CF ₃ ) ₂ —. Also for these, a compound having a plurality of bonding groups may be used as a composition.

  Examples of the monomer represented by the general formula (5) satisfying these requirements include 2,2′dibromobisphenol A compound, 2,2 ′, 6,6′tetrabromobisphenol A compound, 2,2′bis (α-bromomethyl). Preferred examples include bisphenol A compounds, 2,2 ′, 6,6′tetrakis (α-bromomethyl) bisphenol A compounds and the like.

  Using the above aromatic diol and the above aromatic dihalide, the polymer is synthesized according to the above basic preparation method. It is desirable that the sulfonic acid-introduced aromatic dihalide is converted into Na salt or K salt in advance and sufficiently dried before being subjected to the reaction.

  The sulfonic acid / bromo group-introduced polymer thus obtained is converted into a phosphonic acid derivative by functional group conversion after polymer synthesis. Conversion from a bromo compound to a phosphonic acid derivative is carried out by reacting a sulfonic acid / bromo group-introduced polymer with a trivalent organic phosphorus compound such as diethyl phosphite, trimethyl phosphite, or triethyl phosphite. The organophosphorus compound is usually used in an amount of 1.0 to 20 times, preferably 1.2 to 10 times the number of moles of Br groups contained in the polymer. When the ratio is less than 1.0 times, the Br group contained in the polymer is not sufficiently converted to a phosphonic acid derivative and remains as a Br group, which is not preferable. When the ratio is more than 20 times, unreacted organic A large amount of phosphorus compound remains, which is not industrially preferable.

  As the solvent for the functional group conversion reaction, nitrile solvents such as acetonitrile and benzonitrile, nitrobenzene, diphenyl ether, benzophenone and the like are preferably used. The reaction temperature is not generally determined depending on the reactivity of the bromo compound to be used and the amount of functional group to be introduced, but is usually room temperature to 200 ° C, preferably 40 to 180 ° C. If the temperature is lower than room temperature, the progress of the reaction may be extremely slow, and a decomposition by-product may be generated at a temperature of 200 ° C. or higher, which is not preferable in either case.

When the polymer using the raw material monomer represented by the general formula (5) is converted into the functional group, the reaction proceeds even without catalyst when the substituent W in the monomer (5) is —CH ₂ —Br. When the substituent W is -Br directly bonded to the aromatic ring, palladium such as iron (II) chloride, cobalt (II) chloride, nickel (II) chloride, tetrakis (triphenylphosphine) palladium (0), etc. In many cases, the reaction proceeds slowly unless a catalyst such as a catalyst is used. In this case, these catalysts are added in an amount ranging from 0.01 to 10 times, preferably from 0.05 to 5 times, most preferably from 0.1 to 1 times the number of moles of Br groups in the polymer. If it is less than 0.01 times, the catalytic action may be insufficient and the reaction may not be completed even if the reaction time is extended. If the amount exceeds 10 times, the load for separating and removing the catalyst afterwards is large. Also, it is not preferable.

  In the polymer thus functionally converted, since the Br group portion is in a phosphonate state, it is then hydrolyzed to regenerate the phosphonate group. For hydrolysis, an inorganic acid such as hydrochloric acid, sulfuric acid or hydrobromic acid is usually used, and a large excess of acid is usually used relative to the equivalent of the phosphonate ester group. Further, after using trimethylsilyl bromide, the treatment may be performed with an inorganic acid. The acid concentration is usually 0.01 to 10 normal. If it is less than 0.01 N, the acidity is weak and the hydrolysis may proceed slowly, and if it exceeds 10 N, the reactor may be corroded, which is not preferable in any case. The hydrolysis is usually carried out in the temperature range of room temperature to 120 ° C., and the reaction time is usually in the range of 5 minutes to 24 hours. These reaction temperature and reaction time are conditions to be optimized depending on the polymer skeleton used, the amount of introduced functional groups, and the type of acid used.

  The sulfonic acid / phosphonic acid-introduced polymer obtained as described above is purified by washing with water and reprecipitation after concentration, and isolated as a solid polymer, in the case of the reaction using the phosphonic acid-introduced aromatic diol. It is. When a metal-containing catalyst is used in the above functional group conversion, it is often preferable to remove the catalyst component by repeating water washing after hydrolysis multiple times.

(Detailed synthesis method 3: Reaction 2 using bromo group-introduced aromatic diol)
After reacting the aromatic diol represented by the general formula (7) with the aromatic dihalide or dinitro compound represented by the general formula (4) to obtain a polymer, Br groups remaining in the obtained polymer A proton conductive polymer represented by the general formula (2) is obtained by reacting with a trivalent phosphorus compound.
_{^{HO-R 1 -C (CH 3}} ) (R 3 (Br) k) -R 1 -OH (7)
R ¹ represents a para-substituted benzene ring.
R ³ (Br) ₁ represents a benzene ring in which at least a part of the 3, 4, and 5 positions with respect to the bond with the C atom is substituted with Br.
k is the average number of substituents per benzene ring, and 1 <k ≦ 3. A raw material having a plurality of substitution numbers may be used as the composition.
L ¹ is a linking group and represents a bond selected from — (single bond), —CH ₂ —, —CF ₂ —, —C (CH ₃ ) ₂ —, and —C (CF ₃ ) ₂ —. Also for these, a compound having a plurality of bonding groups may be used as a composition.

Preferred examples of the monomer represented by the general formula (7) that satisfies these requirements include compounds represented by the following structural formula.

  This method can be carried out in the same manner as in Detailed Synthesis Method 2: Reaction 1 using a bromo group-introduced aromatic diol.

(Detailed synthesis method 4: Reaction using aromatic diol having no functional group introduced)
After reacting the aromatic diol represented by the general formula (6) with the aromatic dihalide or dinitro compound represented by the general formula (4) to obtain a polymer, the resulting polymer is treated with a Br agent to produce Br. A proton conductive polymer represented by the general formula (1) is obtained by introducing a group and then reacting the Br group with a trivalent phosphorus compound.
HO-R ¹ (Me) _l -L ¹ -R ¹ (Me) _l -OH (6)
However, R ¹ (Me) ₁ represents a benzene ring in which the para position is the polymer main chain, and all the ortho positions relative to the OH group are H, or a part or all of them are Me groups.
l is the average number of Me groups per benzene ring, and 0 ≦ l ≦ 2. A raw material having a plurality of substitution numbers may be used as the composition.
L ¹ is a linking group and represents a bond selected from — (single bond), —CH ₂ —, —CF ₂ —, —C (CH ₃ ) ₂ —, and —C (CF ₃ ) ₂ —. Also for these, a compound having a plurality of bonding groups may be used as a composition.

  Using the above aromatic diol and the above aromatic dihalide, the polymer is synthesized according to the above basic preparation method. The obtained polymer is converted to a phosphonic acid group by the same method as in the detailed synthesis method 2: reaction 1 using a bromo group-introduced aromatic diol after the specific site of the polymer is converted to Br by the following method.

  In the polymer produced from the monomer of the general formula (6), a brominating agent such as N-bromosuccinimide (NBS) is used when the Me group directly bonded to the aromatic ring present in (6) is converted to an α-bromomethyl group. Is preferably used. In this case, NBS is usually used in an amount of 1.0 to 5 times, preferably 1.0 to 3 times the number of moles of reactive Me groups in the polymer. If it is less than 1.0 times, sufficient Br group introduction may not be possible. If it exceeds 5 times, the α bromomethyl group once produced is further converted to Br and converted into α, α 'dibromomethyl groups. Therefore, it is not preferable. Further, azobisisobutyronitrile (AIBN) may be used as a reaction initiator. As the reaction solvent, usually, halogen solvents such as dichloromethane, chloroform and carbon tetrachloride, and nitrile solvents such as acetonitrile and benzonitrile can be preferably used. The reaction temperature is usually from room temperature to 150 ° C. The reaction time is usually in the range of 5 minutes to 24 hours. The reaction temperature and reaction time are factors that should be optimized because they vary significantly depending on the polymer raw material and reaction solvent used.

  In the polymer produced from the monomer of general formula (6), when there is no Me group directly connected to the aromatic ring present in (6) (when l = 0), and the hydrogen atom of the aromatic ring is directly converted to a bromo group In this case, bromine is used as a brominating agent. In this case, the hydrogen atom at the ortho position of the ether bond generated when the aromatic diol component forms a polymer is preferentially Br, but bromine as a reactant is in the number of moles of the hydrogen atom. The amount is usually 1.0 to 20 times, preferably 1.2 to 10 times. If it is less than 1.0 times, sufficient Br conversion may not proceed, and if it exceeds 20 times, the load for removing the remaining unreacted bromine is large, which is not preferable in either case. This reaction may be carried out using bromine itself as a solvent without adding another solvent, but a halogen-based solvent such as dichloromethane, chloroform, carbon tetrachloride or the like may be used.

  The polymer having the Br group thus obtained is converted into a phosphonic acid group in the same manner as in the detailed synthesis method 2: Reaction 1 using a bromo group-introduced aromatic diol, and the target product is represented by the general formula (1 ) Polymer can be obtained.

(Molecular weight of polymer, functional group weight)
The sulfonic acid / phosphonic acid-introduced polymer obtained by each method as described above has a molecular weight measured by solution viscosity measurement or GPC in the same manner as ordinary PES and PEEK polymers. In the present invention, the inherent viscosity by solution viscosity measurement or the weight average molecular weight Mw measured by GPC is used.

  When inherent viscosity is used, the polymer of the present invention has an inherent viscosity in the range of usually 0.3 to 3.0, preferably 0.35 to 2.5 in any system. If it is less than 0.3, the polymer may not have sufficient strength and film formation may not be possible, and if it exceeds 3.0, the viscosity when dissolved in a solvent is high, and a polymer solution having a concentration necessary for film formation is present. There is a possibility that it cannot be prepared, which is not preferable in any case. When Mw is used, the Mw of the polymer of the present invention is usually in the range of 5,000 to 10,000,000, preferably 10,000 to 5,000,000 in any system. If it is less than 5,000, the polymer may not have sufficient strength and film formation may not be possible, and if it exceeds 10,000,000, the viscosity when dissolved in a solvent is high, and the polymer solution at the concentration required for film formation is high. There is a possibility that it cannot be prepared, which is not preferable in any case.

  In addition, two kinds of acidic functional groups, sulfonic acid and phosphonic acid, are introduced into the polymer of the present invention, and the ion exchange capacity (IEC) can be defined for each. Here, phosphonic acid is originally a divalent acid group, but since the dissociation constant at the second stage is very small, it is treated here as a monovalent acid group for convenience.

  Assuming that the amount of sulfonic acid-derived acid groups is IEC (S), IEC (S) is preferably in the range of 0.5 to 4.0 meq / g, more preferably 1.0 to 3.0 meq / g. If IEC (S) is less than 0.5, proton conductivity is low and may not be used as an electrolyte. If it exceeds 4.0, solubility in water will increase, and when used as an electrolyte membrane. There is a possibility of dissolving in condensed water, which is not preferable in either case. On the other hand, IEC (P) is preferably 0.1 to 7.0 meq / g, and more preferably 0.5 to 5 meq / g, assuming that the amount of acid group derived from phosphonic acid is IEC (P). If IEC (P) is less than 0.1, it may not contribute to proton conductivity under the low humidification condition, which is the effect of the introduced phosphonic acid. If it exceeds 7.0, it will be the same as in the case of sulfonic acid. Since solubility in water increases, it is not preferable.

(Evaluation of proton conductivity after thinning)
In order to evaluate the proton conductivity of the proton conducting polymer according to an embodiment of the present invention, a means for measuring the proton conductivity by forming a thin film will be described below.

(Coating solvent)
The polymer of an embodiment of the present invention can be processed into a thin film by, for example, a casting method. Solvents for preparing thin films by the casting method include amide solvents such as N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), or dimethyl sulfone. Xoxide (DMSO) or the like is preferably used. The amount of solvent used for the polymer varies depending on the concentration and viscosity of the target solution, but usually the total solid content of the polymer is 3 to 30% by weight, preferably 5 to 25% based on the total solution amount. It is preferable to use a solvent so that the amount becomes wt%.

(Additive)
In forming a film by casting, the solution is required to have uniform dispersion, uniformity during coating, peelability from the cast film, and the like. For this purpose, a surfactant may be used in the present invention. As the surfactant, a nonionic surfactant is particularly preferably used. When 0.005 to 5% by weight, preferably 0.01 to 1% by weight, based on the weight of the solution is added, the uniformity of the resulting film is improved.

(Coating method / substrate)
When the casting method is used, spin coater, bar coating or the like is preferably used. At this time, glass or the like may be used as the substrate, but a polymer film having good heat resistance and peelability may be used. For example, polyphenylene sulfide (PPS), polyimide film, polyethylene terephthalate (PET) film, polyethylene naphthalate ( PEN) film, polytetrafluoroethane (PTFE) film and the like are preferably used. Moreover, the film which formed thin films, such as polyvinyl alcohol and a polyimide, on the film surface, and can improve the peelability can also be used.

(Drying and heat treatment)
The solvent component is removed from the solution thus cast by a drying process. Drying is usually performed with a hot plate, hot air dryer, or vacuum dryer. The drying temperature varies depending on the solvent used and the properties of the film to be produced, but cannot be generally stated, but is usually room temperature to 200 ° C, preferably 40 ° C. Performed in the range of ~ 150 ° C. The drying time is usually in the range of 10 seconds to 10 hours, preferably 30 seconds to 5 hours. Further, a method of increasing the temperature and performing additional heat treatment after removing the solvent to some extent at a low temperature is also preferably used.

(Basic cell configuration for proton conductivity measurement)
A method for measuring the proton conduction performance of the polymer membrane is described below. The method is similar to the basic cell structure of a polymer electrolyte fuel cell. As shown in FIG. 1, the basic cell for measuring proton conduction performance includes a membrane 10, a pair of gas sealing materials 20a and 20b, a pair of It includes electrodes 12a, 12b and a pair of separators 30a, 30b. The gas sealing materials 20a and 20b are disposed with the film 10 interposed therebetween. The gas seal material 20a is provided with an electrode 12a penetrating from the membrane 10 side to the separator 30a side. Similarly, the gas seal material 20b is provided with an electrode 12b penetrating from the membrane 10 side to the separator 30b side. As the electrodes 12a and 12b, carbon paper made of fibrous carbon is preferably used. Separator 30a, 30b is provided in the outer side of gas seal material 20a, 20b, respectively, and the part pinched | interposed into separator 30a, 30b becomes a sealed area | region. The separators 30a and 30b function as gas flow paths and current collector plates, respectively. Gas sealability is enhanced by further disposing gas seal materials 20a and 20b inside the separators 30a and 30b.

  This cell is nonpolar because there is no difference between the two poles across the membrane 10, but the anode / cathode is defined for convenience. The temperature of the cell is controlled by a heater installed in the separator or on the outer periphery of the cell. Further, humidified nitrogen gas is supplied to both anode / cathode electrodes, thereby controlling the humidified state of the internal proton conductive polymer membrane. The humidification of the gas supplied to the anode / cathode is controlled as a dew point when the gas is humidified through, for example, a bubbler, and the dew points of the anode / cathode gas are substantially the same when evaluating the membrane of the present invention. . Further, the humidification temperature (dew point) of the gas with respect to the cell control temperature is indicated as the relative humidity (RH) in the cell. Proton conductivity is often measured at multiple points by changing the cell temperature and relative humidity.

(Proton conductivity measurement method)
The cell is subjected to impedance measurement using an AC impedance method, and a resistance component caused by proton conduction is separated from the obtained result. Specifically, for example, an AC sine wave of 100 kHz to 0.1 Hz is applied to the cell, and the real and imaginary components of the obtained impedance are plotted on the XY axis (Nyquist plot). In this method, the axial component is Rm. From this Rm, the length L1 in contact with the electrodes, the distance L2 between the electrodes, the thickness d of the membrane and the proton transfer resistance Rm generated between the electrodes of the cell, the proton conductivity can be calculated from the following equation.
Proton conductivity σ (S / cm) = L2 (cm) / (Rm (Ω) x d (cm) x L1 (cm))

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

[Reference Example 1] Synthesis of phosphonic acid-introduced polyether sulfone (Polymerization) 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane 2.70 g, bis (4-fluorophenyl) sulfone 2.41 g, carbonic acid After adding 2.62 g of potassium to a 50 mL one-necked eggplant flask, 20 mL of DMAc and 10 mL of toluene that had been dehydrated by distillation in advance were added. The inside of the reaction vessel was deaerated with a vacuum pump, and then purged with nitrogen. This operation was repeated three times. This solution was heated using an oil bath at 170 ° C. and dehydrated with a Dean-Stark trap for 6 hours, and then the bath temperature was raised to 190 ° C. and further heated and stirred for 24 hours to conduct a polymerization reaction. After cooling the reaction solution to room temperature, this solution was added dropwise to a mixed solution of methanol and water (7: 1) for reprecipitation. The precipitate was collected by filtration and then dried at 120 ° C. under reduced pressure for 10 hours. The yield was 95% (5.00 g). Identification was performed by 1H-NMR.

  In the above 1H-NMR, the peak derived from the aromatic proton (12H) is on the high frequency side (6.5 to 8.0 ppm), and the peak derived from the protons (12H) of the four methyl groups substituted on the aromatic ring is approximately Propane proton (6H) was observed at about 1.7 ppm at 2.0 ppm, confirming that the desired polymer was synthesized.

  (Bromination reaction) After adding 4.60 g of the obtained polymer, 0.152 g of azobisisobutyronitrile, and 9.86 g of NBS to a 50 mL two-necked flask filled with nitrogen gas, 40 mL of chloroform previously dehydrated by distillation was added. Stirring was carried out at 24 ° C. for 24 hours. After the reaction, chloroform was removed, and THF was added to dissolve the polymer. Reprecipitation was performed by dropping this solution into 2-propanol. The precipitate was collected by filtration and then dried at 100 ° C. under reduced pressure for 10 hours. The product was identified by 1H-NMR.

In the 1H-NMR, the peak derived from the aromatic proton (12H) is on the high frequency side (6.5 to 8.0 ppm), and the peak derived from the proton at the benzyl position (—CH ₂ —Br) (5.6H) is about 4.3 The peak derived from protons of four methyl groups substituted on the aromatic ring (3.6H) is observed at about 2.0 ppm and the propane proton (6H) at about 1.7 ppm at ppm, and the target polymer is synthesized. Confirmed that. As a result of calculating the bromination rate from the number of protons at the benzyl position when the number of aromatic protons was 12H, the bromination rate was 70%.

  (Introduction of phosphonate ester) 1.34 g of the obtained polymer, 3.3 mL of triethyl phosphite, and 20 mL of acetonitrile were added to a 100 mL eggplant flask filled with nitrogen gas. This solution was slowly heated to 130 ° C. and then heated and stirred for 12 hours. After the reaction solution was cooled to room temperature, reprecipitation was performed by adding dropwise to 2-propanol. The precipitate was collected by filtration and then dried at 120 ° C. under reduced pressure for 10 hours. The yield was 90% (1.3 g). The product was identified by 1H-NMR.

In the 1H-NMR, the peak derived from the aromatic proton (12H) is on the high frequency side (6.5 to 8.0 ppm), and the peak derived from the methylene proton of the ethyl phosphonate group (11.2H) is about 4.0 ppm. , The peak derived from the proton at the benzyl position (—CH ₂ —PO (OEt) ₂ ) (5.6H) is about 4.3 ppm, and the peak derived from the protons of the four methyl groups substituted on the aromatic ring (3.6H ) Is observed at about 2.0 ppm, the propane proton (6H) is observed at about 1.7 ppm, and the peak derived from the methyl proton of the ethyl phosphonate group (16.8H) is observed at about 1.2 ppm. Confirmed that.

  After the introduction of the phosphonate group, the peak derived from the proton at the benzyl position shifted to around 3 ppm, and peaks derived from methylene and methyl of the ethyl phosphonate group were observed at 4.0 ppm and 1.2 ppm, respectively. As with the calculation of bromination rate, the amount of introduction was calculated from the number of protons in the ethyl phosphonate group based on aromatic protons. As a result, the amount of introduction was 70%, that is, all bromine was replaced with phosphonates. It was confirmed.

  (Hydrolysis) 1.2 g of the polymer obtained, 20 mL of hydrobromic acid and 100 mL of DMAc were added to a 200 mL eggplant flask filled with nitrogen gas, and refluxed at 100 ° C. for 12 hours. After the reaction solution was cooled to room temperature, water was added, filtration was performed, and the residue was washed with a large amount of water. The obtained polymer was dried at 120 ° C. under reduced pressure for 10 hours. The yield was 90% (1.00 g). The inherent viscosity was 1.18. The final product having the following structure was identified by 1H-NMR.

In the above 1H-NMR, the peak derived from the aromatic proton (12H) is derived from the benzylic proton (—CH ₂ —PO (OEt) ₂ ) (5.6H) on the high frequency side (6.5 to 8.5 ppm). The peak was observed at about 3.8 ppm, the peak derived from the protons of the four methyl groups substituted on the aromatic ring (3.6 H) at about 2.0 ppm, and the propane proton (6 H) at about 1.7 ppm. It was confirmed that the polymer was synthesized.

  After the hydrolysis, the peak derived from the phosphonate group disappeared, and it was confirmed that the hydrolysis reaction proceeded completely. The peak derived from the benzylic proton was shifted to around 3.8 ppm.

[Reference Example 2] Synthesis of sulfonic acid-introduced polyethersulfone
2,1-bis (4-hydroxyphenyl) propane 1.16 g, sodium 3,3-disulfonate-4,4'-dichlorodiphenyl sulfone 1.30 g, bis (4-fluorophenyl) sulfone 0.622 g, potassium carbonate 1.41 g After adding to a 50 mL three-necked flask filled with nitrogen gas, 9 mL of DMAc and 7 mL of toluene that had been dehydrated by distillation in advance were added. This solution was heated using an oil bath at 170 ° C. and dehydrated with a Dean-Stark trap for 6 hours, and then the bath temperature was raised to 180 ° C. and further heated and stirred for 48 hours to carry out a polymerization reaction. The reaction solution was cooled to room temperature, and then reprecipitated by adding dropwise to a mixed solvent of methanol and water (7: 1 v / v). The precipitate was collected by filtration and then dried at 140 ° C. under reduced pressure for 6 hours. The yield of the sulfonic acid-introduced polyethersulfone represented by the following structural formula was 80% (2.70 g). The inherent viscosity was 0.98. Identification was performed by 1H-NMR.

In the 1H-NMR, a peak derived from an aromatic proton (about 15H) is observed on the high frequency side (6.5 to 8.5 ppm), and a propane proton (6H) is observed at about 1.7 ppm, and the target polymer is synthesized. I confirmed.

  A peak derived from an aromatic proton was observed on the high frequency side (6.5 to 8.0 ppm), and a proton of propane was observed at about 1.7 ppm, confirming that the target polymer was synthesized. Moreover, as a result of calculating the introduction amount of the sulfonic acid group from the number of aromatic protons based on the number of protons of propane, it was confirmed that the amount of the sulfonic acid group represented by the above structural formula was introduced.

[Example 1] Synthesis of sulfonic acid / phosphonic acid-introduced polyethersulfone (1) using phosphonic acid group-introduced aromatic diol

  (Polymerization) 1,1-bis (4-hydroxyphenyl) -1- (phenyl 4-phosphonate) ethane 0.448 g, 2,2-bis (4-hydroxyphenyl) propane 0.644 g, 3,3-disulfonic acid After adding 0.572 g of sodium-4,4′-dichlorodiphenylsulfone, 0.574 g of bis (4-fluorophenyl) sulfone, and 1.11 g of potassium carbonate to a 50 mL three-necked flask filled with nitrogen gas, Toluene 8 mL was added. This solution was heated using an oil bath at 170 ° C. and dehydrated with a Dean-Stark trap for 6 hours, and then the bath temperature was raised to 190 ° C. and further heated and stirred for 48 hours to conduct a polymerization reaction. The reaction solution was cooled to room temperature, and then reprecipitated by adding dropwise to a mixed solvent of methanol and water (7: 1 v / v). The precipitate was collected by filtration and then dried at 140 ° C. under reduced pressure for 6 hours.

  (Acid treatment) 6N hydrochloric acid was added to the obtained polymer, and the mixture was stirred at room temperature for 30 minutes. The polymer was collected by filtration and washed with a large amount of water. The inherent viscosity was 0.35. Identification was performed by 1H-NMR as in the reference example.

In the above 1H-NMR, the peak derived from the aromatic proton (about 8.2H) is on the high frequency side (6.5 to 8.5ppm), and the peak derived from the proton of the phosphonic acid group (-OH) is about 4.8ppm In addition, the ethane proton (0.45H) was observed at about 2.2 ppm and the propane proton (2.1H) was observed at about 1.7 ppm, confirming that the desired polymer was synthesized.

[Example 2] Synthesis of sulfonic acid / phosphonic acid-introduced polyether sulfone (1) using bromo group-introduced aromatic diol

  (Polymerization) 1- (4-Bromophenyl) -1,1-bis (4-hydroxyphenyl) ethane 2.12 g, 2,2-bis (4-hydroxyphenyl) propane 1.31 g, 3,3-sodium sodium disulfonate DMAc 30mL and toluene 10mL, which were dehydrated by distillation after adding 4,3'-dichlorodiphenyl sulfone 2.63g, bis (4-fluorophenyl) sulfone 1.46g, potassium carbonate 3.18g to a 50mL three-necked flask filled with nitrogen gas Was added. This solution was heated using an oil bath at 170 ° C. and dehydrated with a Dean-Stark trap for 6 hours, and then the bath temperature was raised to 190 ° C. and further heated and stirred for 24 hours to conduct a polymerization reaction. The reaction solution was cooled to room temperature, diluted with DMAc and filtered to remove residual insoluble potassium carbonate. After the filtered solution was concentrated by a rotary evaporator, this solution was added dropwise to 2-propanol for reprecipitation. The precipitate was collected by filtration and then dried at 120 ° C. under reduced pressure for 10 hours. The yield was 95% (6.70 g).

  (Phosphonate introduction) 2.04 g of the obtained polymer, 8.55 mL of diethyl phosphite, 1.03 g of tetrakis (triphenylphosphine) palladium, 9.26 mL of triethylamine, and 20 mL of DMF were added to a two-necked flask filled with nitrogen gas. . This solution was heated and stirred in an oil bath at 120 ° C. for 72 hours. After the reaction solution was cooled to room temperature, reprecipitation was performed by adding dropwise to 2-propanol. The precipitate was collected by filtration and then dried at 120 ° C. under reduced pressure for 10 hours. The yield was 90% (2.2 g).

(Hydrolysis) 1.9 g of the obtained polymer and 25 mL of hydrobromic acid were added to a 50 mL flask and refluxed at 100 ° C. for 12 hours. The reaction solution was cooled to room temperature, filtered, and the filtrate was washed with a large amount of water. The obtained polymer was dried at 120 ° C. under reduced pressure for 10 hours. The yield was 90% (1.4 g). The inherent viscosity was 2.0. As a result of GPC measurement, the weight average molecular weight was 339,000. When the amount of acid groups introduced was confirmed from 1H-NMR as in the Reference Example, it was confirmed that the structure was as follows.

[Example 3] Synthesis of sulfonic acid / phosphonic acid-introduced polyether sulfone (1) using an aromatic diol containing a methyl group

  (Polymerization) 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane 1.40 g, 3,3-disulfonic acid-4,4'-dichlorodiphenyl sulfone 1.13 g, bis (4-fluorophenyl) sulfone After adding 0.624 g and 2.38 g of potassium carbonate to a 50 mL three-necked flask filled with nitrogen gas, 12 mL of DMAc and 8 mL of toluene that had been dehydrated by distillation in advance were added. This solution was heated using an oil bath at 170 ° C. and dehydrated with a Dean-Stark trap for 12 hours, and then the bath temperature was raised to 190 ° C. and further heated and stirred for 48 hours to carry out a polymerization reaction. The reaction solution was cooled to room temperature, diluted with DMAc and filtered to remove residual insoluble potassium carbonate. After the filtered solution was concentrated by a rotary evaporator, this solution was added dropwise to 2-propanol for reprecipitation. The precipitate was collected by filtration and then dried at 120 ° C. under reduced pressure for 10 hours. The yield was 95% (3.00 g).

  (Bromination reaction) After adding 0.52 g of the obtained polymer, 0.043 g of azobisisobutyronitrile, 0.93 g of NBS to a 50 mL two-necked flask filled with nitrogen gas, 3 mL of chloroform previously dehydrated by distillation was added. Stirring was carried out at 15 ° C. for 15 hours. After the reaction, chloroform was removed, and DMAc was added to dissolve the polymer. Reprecipitation was performed by dropping this solution into 2-propanol. The precipitate was collected by filtration and then dried at 100 ° C. under reduced pressure for 10 hours. The bromination rate was 50%.

  (Introduction of phosphonate ester) 0.88 g of the obtained polymer, 2.98 mL of diethyl phosphite, 0.36 g of tetrakis (triphenylphosphine) palladium, 3.18 mL of triethylamine, and 10 mL of DMAc were added to a two-necked flask filled with nitrogen gas. . This solution was heated and stirred in an oil bath at 100 ° C. for 24 hours. After the reaction solution was cooled to room temperature, reprecipitation was performed by adding dropwise to 2-propanol. The precipitate was collected by filtration and then dried at 120 ° C. under reduced pressure for 10 hours. The yield was 90% (0.8 g).

(Hydrolysis) 0.8 g of the obtained polymer and 10 mL of hydrobromic acid were added to a 50 mL flask and refluxed at 100 ° C. for 24 hours. The reaction solution was cooled to room temperature, filtered, and the filtrate was washed with a large amount of water. The obtained polymer was dried at 120 ° C. under reduced pressure for 10 hours. The yield was 90% (0.75 g). The inherent viscosity was 0.95. When the amount of acid groups introduced was confirmed from 1H-NMR as in the Reference Example, it was confirmed that the structure was as follows.

[Example 4] Synthesis of sulfonic acid / phosphonic acid-introduced polyether sulfone (2) using bromo group-introduced aromatic diol

  (Polymerization) 1- (3,5-dibromophenyl) -1,1-bis (4-hydroxyphenyl) ethane 2.27 g, sodium 3,3-disulfonate-4,4′-dichlorodiphenylsulfone 1.16 g, bis ( After adding 0.444 g of 4-fluorophenyl) sulfone and 1.40 g of potassium carbonate to a 25 mL eggplant flask filled with nitrogen gas, 12 mL of DMAc and 8 mL of toluene that had been dehydrated by distillation in advance were added. The inside of the reaction vessel was deaerated with a vacuum pump, and then purged with nitrogen. This operation was repeated three times. This solution was heated using an oil bath at 170 ° C. and dehydrated with a Dean-Stark trap for 6 hours, and then the bath temperature was raised to 180 ° C. and further heated and stirred for 12 hours to carry out a polymerization reaction. The reaction solution was cooled to room temperature, diluted with DMAc and filtered to remove residual insoluble potassium carbonate. After the filtered solution was concentrated by a rotary evaporator, this solution was added dropwise to 2-propanol for reprecipitation. The precipitate was collected by filtration and then dried at 120 ° C. under reduced pressure for 10 hours. The yield was 95% (4.0 g).

  (Introduction of phosphonate ester) 1.52 g of the obtained polymer, 5.12 mL of diethyl phosphite, 1.24 g of tetrakis (triphenylphosphine) palladium, 5.55 mL of triethylamine, and 15 mL of DMF were added to a two-necked flask filled with nitrogen gas. . This solution was heated and stirred in a 100 ° C. oil bath for 72 hours. After the reaction solution was cooled to room temperature, reprecipitation was performed by adding dropwise to 2-propanol. The precipitate was collected by filtration and then dried at 120 ° C. under reduced pressure for 10 hours. The yield was 94% (1.78 g).

(Hydrolysis) 1.5 g of the obtained polymer, 10 mL of 1,4-dioxane, and 14 mL of hydrobromic acid were added to a 50 mL flask and refluxed at 100 ° C. for 20 hours. The reaction solution was cooled to room temperature, filtered, and the filtrate was washed with a large amount of water. The obtained polymer was dried at 120 ° C. under reduced pressure for 10 hours. The yield was 95% (1.1 g). The inherent viscosity was 2.0. When the amount of acid groups introduced was confirmed from 1H-NMR as in the Reference Example, it was confirmed that the structure was as follows.

(Evaluation of proton conductivity)
<Formation of sulfonic acid / phosphonic acid-introduced polyethersulfone (1) thin film using cast method>
1 g of the polymer synthesized in Example 4 was dissolved in 5.7 mL of DMSO to prepare a polymer solution of about 15% by weight. The prepared solution was filtered through a 10 μm filter, cast on a glass substrate, and bar-coated. After drying at 60 ° C. for 2 hours under reduced pressure, the temperature was raised to 100 ° C. and drying was further performed for 3 hours. After drying, it was immersed in water, and the film was peeled off to obtain a self-supporting film.

  The proton conductivity of the obtained sulfonic acid / phosphonic acid-introduced polyethersulfone (1) thin film was measured by the proton conductivity measuring method described above.

  For the polyether sulfone of Comparative Example 1 and the sulfonic acid-introduced polyether sulfone of Comparative Example 2, a thin film was formed in the same manner as described above, and the proton conductivity was measured by the proton conductivity measuring method described above.

The results obtained for Example 4, Comparative Example 1 and Comparative Example 2 are shown in Table 1.

  From this result, it was confirmed that the sulfonic acid / phosphonic acid-introduced polyethersulfone (1) thin film of Example 4 exhibited high proton conduction performance under medium temperature and low humidification conditions.

10 membrane, 12a, 12b electrode, 20a, 20b gas seal material, 30a, 30b separator

Claims (12)

A proton conductive polymer represented by the following general formula (1).
− {O−R ¹ (X) _l −L ¹ −R ¹ (X) _l −O−R ² (Y) _m −L ² −R ² (Y) _m −} _n (1)
(1) In the formula, R ¹ (X) _l represents a benzene ring in which the para-position is the polymer main chain, and at least a part of the ortho-position to the O atom bond is substituted by the substituent X Indicates.
X represents —P (═O) (OH) ₂ or —CH ₂ —P (═O) (OH) ₂ .
l is the average number of substituents per benzene ring, and 0 <l ≦ 2.
L ¹ is a linking group and represents a bond selected from — (single bond), —CH ₂ —, —CF ₂ —, —C (CH ₃ ) ₂ —, and —C (CF ₃ ) ₂ —.
R ² (Y) _m represents a benzene ring whose para-position is the polymer main chain, and that at least a part of the ortho-position with respect to the O atom bond is substituted with the substituent Y.
Y denotes a -SO ₃ H.
m is the average number of substituents per benzene ring, and 0 <m ≦ 2.
L ² is a linking group and represents a bond selected from —C (═O) — and —SO ₂ —.
n represents the average number of repeating units of the polymer, and the average value is determined by the weight average molecular weight determined separately.   The proton conducting polymer according to claim 1, wherein the weight average molecular weight is in the range of 5,000 to 10,000,000.   3. The proton conductive polymer according to claim 1, wherein the inherent viscosity is in the range of 0.3 to 3.0.   The acid value per polymer weight when the substituent X or Y is regarded as a monovalent acid group is in the range of 0.1 to 5 meq / g and 0.5 to 4 meq / g, respectively. The proton conducting polymer described. A proton conductive polymer represented by the following general formula (2).
− {O−R ¹ −C (CH ₃ ) (R ³ (X) _k ) −R ¹ −O−R ² (Y) _m −L ² −R ² (Y) _m −} _n (2)
(2) In the formula, R ¹ represents a para-substituted benzene ring.
R ³ (X) ₁ represents a benzene ring in which at least a part of the 3, 4, and 5 positions with respect to the bond with the C atom is substituted with the substituent X.
X represents —P (═O) (OH) ₂ or —CH ₂ —P (═O) (OH) ₂ .
l is the average number of substituents per benzene ring, and 0 <l ≦ 3.
R ³ (Y) _m represents a benzene ring in which the para position is the polymer main chain, and indicates that at least a part of the ortho position with respect to the O atom bond is substituted with the substituent Y.
Y denotes a -SO ₃ H.
m is the average number of substituents per benzene ring, and 0 <m ≦ 2.
L ² is a linking group and represents a bond selected from —C (═O) — and —SO ₂ —.
n represents the average number of repeating units of the polymer, and the average value is determined by the weight average molecular weight determined separately.   6. The proton conducting polymer according to claim 5, wherein the weight average molecular weight is in the range of 5,000 to 10,000,000.   The proton conductive polymer according to claim 5 or 6, wherein the inherent viscosity is in the range of 0.3 to 3.0.   The acid value per polymer weight when the substituent X or Y is regarded as a monovalent acid group is in the range of 0.1 to 5 meq / g and 0.5 to 4 meq / g, respectively. The proton conducting polymer described. Proton capable of obtaining a proton conductive polymer represented by the general formula (1) by reacting the aromatic diol represented by the general formula (3) with the aromatic dihalide or dinitro compound represented by the general formula (4). A method for producing a conductive polymer.
HO-R ¹ (X) _l -L ¹ -R ¹ (X) _l -OH (3)
Z−R ² (Y) _m −L ² −R ² (Y) _m −Z (4)
(3) In the formula, R ¹ (X) _l represents a benzene ring whose para-position is the polymer main chain, and that at least a part of the ortho-position to the OH group is substituted by the substituent X. Show.
X represents —P (═O) (OH) ₂ or —CH ₂ —P (═O) (OH) ₂ . In the polymer synthesis reaction, these are alkali salts, ammonium salts, amine salts of Na, K, NH ₄ , NR _{4 and the} like (R is H or an alkyl group), ester compounds such as Me and Et, and partial ester compounds. May be.
l is the average number of substituents per benzene ring, and 0 <l ≦ 2. A raw material having a plurality of substitution numbers may be used as the composition.
L ¹ is a linking group and represents a bond selected from — (single bond), —CH ₂ —, —CF ₂ —, —C (CH ₃ ) ₂ —, and —C (CF ₃ ) ₂ —. Also for these, a compound having a plurality of bonding groups may be used as a composition.
(4) In the formula, R ² (Y) _m represents a benzene ring in which the para position is the polymer main chain, and at least a part of the ortho position with respect to the O atom bond is substituted by the substituent Y. Indicates.
Y denotes a -SO ₃ H. In the polymer synthesis reaction, these may be alkali salts, ammonium salts, or amine salts of Na, K, NH ₄ , NR _{4 and the} like (R is H or an alkyl group).
m is the average number of substituents per benzene ring, and 0 <m ≦ 2. A raw material having a plurality of substitution numbers may be used as the composition.
L ² is a linking group and represents a bond selected from —C (═O) — and —SO ₂ —.
Z represents -F, -Cl, a terminal group selected from -NO _2. After reacting the aromatic diol represented by the general formula (5) with the aromatic dihalide or dinitro compound represented by the general formula (4) to obtain a polymer, Br groups remaining in the obtained polymer A method for producing a proton conductive polymer, wherein the proton conductive polymer represented by the general formula (1) is obtained by reacting with a trivalent phosphorus compound.
HO-R ¹ (W) _l -L ¹ -R ¹ (X) _l -OH (5)
(5) In the formula, R ¹ (W) _l represents a benzene ring in which the para-position is the polymer main chain, and at least a part of the ortho-position to the OH group is substituted by the substituent W. Show.
W represents —Br or —CH ₂ —Br.
l is the average number of substituents per benzene ring, and 0 <l ≦ 2. A raw material having a plurality of substitution numbers may be used as the composition.
L ¹ is a linking group and represents a bond selected from — (single bond), —CH ₂ —, —CF ₂ —, —C (CH ₃ ) ₂ —, and —C (CF ₃ ) ₂ —. Also for these, a compound having a plurality of bonding groups may be used as a composition. After reacting the aromatic diol represented by the general formula (6) with the aromatic dihalide or dinitro compound represented by the general formula (4) to obtain a polymer, the resulting polymer is treated with a Br agent to produce Br. A method for producing a proton conductive polymer, wherein a proton conductive polymer represented by the general formula (1) is obtained by introducing a group and then reacting a Br group with a trivalent phosphorus compound.
HO-R ¹ (Me) _l -L ¹ -R ¹ (Me) _l -OH (6)
(6) In the formula, R ¹ (Me) _l represents a benzene ring in which the para-position is the polymer main chain, and all the ortho-positions to the OH group are H, or a part or all of them are Me groups. Show.
l is the average number of Me groups per benzene ring, and 0 ≦ l ≦ 2. A raw material having a plurality of substitution numbers may be used as the composition.
L ¹ is a linking group and represents a bond selected from — (single bond), —CH ₂ —, —CF ₂ —, —C (CH ₃ ) ₂ —, and —C (CF ₃ ) ₂ —. Also for these, a compound having a plurality of bonding groups may be used as a composition. After reacting the aromatic diol represented by the general formula (7) with the aromatic dihalide or dinitro compound represented by the general formula (4) to obtain a polymer, Br groups remaining in the obtained polymer A method for producing a proton conductive polymer, wherein a proton conductive polymer represented by the general formula (2) is obtained by reacting with a trivalent phosphorus compound.
_{^{HO-R 1 -C (CH 3}} ) (R 3 (Br) k) -R 1 -OH (7)
(7) In the formula, R ¹ represents a para-substituted benzene ring.
R ³ (Br) ₁ represents a benzene ring in which at least a part of the 3, 4, and 5 positions with respect to the bond with the C atom is substituted with Br.
k is the average number of substituents per benzene ring and takes a value between 0.01 and 3. A raw material having a plurality of substitution numbers may be used as the composition.
L ¹ is a linking group and represents a bond selected from — (single bond), —CH ₂ —, —CF ₂ —, —C (CH ₃ ) ₂ —, and —C (CF ₃ ) ₂ —. Also for these, a compound having a plurality of bonding groups may be used as a composition.

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