JP5625317B2 - Novel aromatic compounds and polyarylene copolymers having aromatic rings containing sulfonic acid groups in the side chains - Google Patents

Description

  The present invention relates to a novel aromatic compound and polyarylene-based copolymer and a proton conductive membrane using the same, and more specifically, an electrolyte for a primary battery, an electrolyte for a secondary battery, a solid polymer electrolyte for a fuel cell, A polyarylene copolymer containing a structure having an aromatic ring sulfonated in a side chain, which is useful for a proton conductive membrane usable for a display element, various sensors, a signal transmission medium, a solid capacitor, an ion exchange membrane, and the like, and The present invention relates to a novel aromatic compound used for the copolymer.

  A fuel cell is a power generation system with high power generation efficiency, low emissions, and low environmental burden. In recent years, with the growing interest in protecting the global environment and escaping from fossil fuel dependence, it is in the spotlight. Fuel cells are expected to be installed in small distributed power generation facilities, power generation devices as driving sources for moving bodies such as automobiles and ships, and mobile phones and mobile personal computers that replace secondary batteries such as lithium ion batteries. ing.

  A polymer electrolyte fuel cell is provided with a pair of electrodes on both sides of a proton-conducting solid polymer electrolyte membrane, and supplies pure hydrogen or reformed hydrogen gas as fuel to one electrode (fuel electrode). Air is supplied as an oxidizing agent to different electrodes (air electrodes) to obtain an electromotive force. In water electrolysis, water is electrolyzed using a solid polymer electrolyte membrane to produce a reverse reaction of the fuel cell reaction to produce hydrogen and oxygen.

However, in actual fuel cells and water electrolysis, side reactions occur in addition to these main reactions. A typical example is the generation of hydrogen peroxide (H ₂ O ₂ ), and the radical species resulting from the hydrogen peroxide cause the solid polymer electrolyte membrane to deteriorate.

  Conventionally, solid polymer electrolyte membranes are commercially available under the trade names Nafion (registered trademark, manufactured by DuPont), Aciplex (registered trademark, manufactured by Asahi Kasei Kogyo Co., Ltd.), and Flemion (registered trademark, manufactured by Asahi Glass Co., Ltd.). Perfluorosulfonic acid membranes that have been used have been used because of their excellent chemical stability.

  However, since perfluorosulfonic acid membranes such as Nafion are difficult to manufacture, there is a problem that they are very expensive, and are widely used in consumer applications such as fuel cell vehicles and household fuel cell power generation systems. It is an obstacle. In addition, since it has a large amount of fluorine atoms in the molecule, the disposal treatment after use also has a problem of a heavy load on the environment.

  In addition, the higher the temperature of the fuel cell and the thinner the proton conductive membrane between the electrodes, the smaller the membrane resistance and the higher the power generation output. However, since these perfluoro acid-based membranes have a thermal deformation temperature of about 80 to 100 ° C., the creep resistance at a high temperature is very poor. Therefore, the power generation temperature when using these membranes in a fuel cell is low. There is a problem that power generation output is limited because it must be kept at 80 ° C. or lower. In addition, the film thickness is poor when used for a long period of time, and in order to prevent a short circuit between the electrodes, a certain degree of film thickness (50 μm or more) is required, and a thin perfluoro acid-based film is used. It is considered difficult.

  In order to solve such problems of perfluorosulfonic acid membranes, solid polymer electrolyte membranes that do not contain fluorine atoms, are cheaper, and have a heat-resistant main chain skeleton that is also used for engineer plastics are currently available. Many studies have been conducted. Polymers in which a main chain aromatic ring of polyarylene, polyether ether ketone, polyether sulfone, polyphenylene sulfide, polyimide, or polybenzazole is sulfonated have been proposed (Non-Patent Documents 1 to 3).

Polymer Preprints, Japan, Vol. 42, no. 7, p. 2490-2492 (1993) Polymer Preprints, Japan, Vol. 43, no. 3, p. 735-736 (1994) Polymer Preprints, Japan, Vol. 42, no. 3, p. 730 (1993)

  The object of the present invention is to solve the problems of the fluorine-based electrolyte membrane and the aromatic-based electrolyte membrane that have been studied conventionally, to improve the cross-linking resistance in a dry environment and the swelling under hydrothermal conditions, and An object of the present invention is to provide a polyarylene copolymer and a polymer electrolyte excellent in conductivity.

As a result of intensive studies to achieve the above object, the present inventors have found that a polymer electrolyte having a heterocyclic ring containing nitrogen in the main chain is a novel material that satisfies the object of the present invention, The present invention has been completed.
That is, the gist of the present invention is as follows.

  [1] Containing a structural unit having a proton conductive group represented by the following general formula (I) and having a heterocyclic structure containing nitrogen represented by the following general formula (II) in the main chain A polyarylene copolymer characterized by comprising:

[In the formula (I), Y represents —CO—, —SO ₂ —, —SO—, a direct bond, — (CF ₂ ) _u — (u is an integer of 1 to 10), —C (CF ₃ ). ₂ represents at least one structure selected from the group consisting of —, Z is a direct bond, or — (CH ₂ ) ₁ — (l is an integer of 1 to 10), —C (CH ₃ ) ₂ —. , -O -, - represents at least one structure selected from the group consisting of S-, Ar is -SO ₃ H or _{-O (CH 2) p SO 3} H or -O (CF _{2) p} SO ₃ An aromatic group having a substituent represented by H is shown. p shows the integer of 1-12, m shows the integer of 0-3, n shows the integer of 0-3, k shows the integer of 1-4. Among the single lines at the end of the structural unit, those not having a substituent displayed on one side mean connection with the adjacent structural unit. ]

[In the formula (II), Ar ³¹ represents a heterocyclic ring containing nitrogen. Among the single lines at the end of the structural unit, those not having a substituent displayed on one side mean connection with the adjacent structural unit. ]
[2] The polyarylene copolymer according to [1], wherein the polyarylene copolymer includes a structural unit having an aromatic structure represented by the following general formula (III).

[In the formula (III), A and D are independently a direct bond, or —CO—, —SO ₂ —, —SO—, — (CF ₂ ) ₁ — (l is an integer of 1 to 10), (CH ₂ ) _l — (l is an integer of 1 to 10), —CR ′ ₂ — (R ′ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group and a halogenated hydrocarbon group), cyclohexylene 1 represents at least one structure selected from the group consisting of a den group, a fluorenylidene group, —O—, and —S—, B is an oxygen atom or a sulfur atom independently, and R ^{1 to} R ¹⁶ are the same as each other May be different, at least selected from the group consisting of a hydrogen atom, a fluorine atom, a nitro group, a nitrile group, or an alkyl group, an allyl group, or an aryl group in which some or all of the hydrogen atoms may be fluorine-substituted. One atom or group is shown. s and t represent an integer of 0 to 4, and r represents 0 or an integer of 1 or more. ]

[3] In the formula (II), Ar ³¹ is pyrrole, 2H-pyrrole, imidazole, pyrazole, isothiazole, isoxazole, pyridine, pyrazine, pyrimidine, pyridazine, indolizine, isoindole, 3H-indole, indole, 1H -Indazole, purine, 4H-quinolidine, quinoline, isoquinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, pteridine, carbazole, carboline, phenanthridine, acridine, perimidine, phenanthroline, phenazine, phenothiazine, furazane, phenoxazine, pyrrolidine, Pyrroline, imidazoline, imidazolidine, pyrazolidine, pyrazoline, piperidine, piperazine, indoline, isoindoline, quinuclidine, oxazol , Benzoxazole, 1,3,5-triazine, Brin, tetrazole, tetrazine, triazole, phenarsazine, benzimidazole, benzotriazole, thiazole, benzothiazole, or structure derived from at least one selected from the group consisting of benzothiadiazole,
Or the polyarylene-type copolymer as described in [1] characterized by including the at least 1 sort (s) of structure chosen from the group which consists of a structure represented by a following formula.

[In the above formula, among the single wires at the ends of the structural units, those on which one or more substituents are not displayed mean connection with adjacent structural units. ]
[4] A polymer electrolyte comprising the polyarylene copolymer according to any one of [1] to [3].
[5] The polymer electrolyte comprising the polyarylene copolymer according to any one of [1] to [3], wherein the ion exchange capacity is 0.5 to 3.5 meq / g.

  According to the present invention, it is inexpensive, has a low environmental impact, has excellent proton conductivity, dimensional stability, mechanical properties, and processability (bondability of proton conductive membrane / gas diffusion layer and electrode layer), chemical Durability against deterioration has also been improved, and since a heterocyclic ring containing nitrogen is introduced in the main chain, if it is included with a structural unit having a sulfonic acid group, it can be swollen in hot water without reducing proton conductivity. Thus, it is possible to provide a polyarylene copolymer and a polymer electrolyte that can be suppressed, improve heat resistance, have high crosslinking resistance, and have excellent power generation performance and power generation durability.

  Hereinafter, the present invention will be described in detail.

< Polyarylene copolymer>
The polyarylene copolymer of the present invention has a structural unit having a sulfonic acid group and a structural unit having a nitrogen-containing heterocyclic structure.
Furthermore, the polyarylene copolymer of the present invention preferably has a structural unit having an aromatic structure.
The polyarylene copolymer having such a structure contains a nitrogen-containing heterocycle in the main chain. The nitrogen-containing heterocyclic group is a basic group having an appropriate strength capable of exhibiting these effects without impairing proton conductivity. Since the nitrogen atom of such a heterocyclic ring has basicity, it forms an ionic interaction with the sulfonic acid group. This enhances the stability of the sulfonic acid group and suppresses the elimination of the sulfonic acid group under high temperature conditions. Similarly, the cross-linking reaction between polymer molecules derived from sulfonic acid groups can be suppressed under high temperature conditions. In addition, since a heterocyclic ring containing nitrogen is introduced in the main chain, when it is included with a structural unit having an ion conductive group, swelling in hot water is suppressed without lowering proton conductivity, and heat resistance is improved. It can be improved and has excellent cross-linking resistance.
For this reason, the electrode electrolyte containing such a polyarylene-based copolymer can generate power even in a wide range of temperatures and humidity, particularly at high temperatures, and can improve power generation output. In addition, even when used at high temperatures, since the ion conductive group such as a sulfonic acid group has high stability, a fuel cell with greatly improved battery life can be obtained.
Here, the term “cross-linking resistance” refers to a property that can withstand the deterioration of the sulfo group at the end of the side chain and the cross-linking of the side chain.

[Structural unit having proton conductive group]
The structural unit having a proton conductive group is represented by the following formula (1). The structural unit having a proton conductive group is preferably a structural unit having a sulfonic acid group.

In the above formula, Ar ¹¹ , Ar ¹² , and Ar ¹³ are each independently at least one structure selected from the group consisting of a benzene ring, a condensed aromatic ring, and a nitrogen-containing heterocyclic ring, which may be substituted with a fluorine atom. A divalent or trivalent group having
Y represents —CO—, —SO ₂ —, —SO—, —CONH—, —COO—, — (CF ₂ ) _u — (u is an integer of 1 to 10), —C (CF ₃ ) _2. -Or indicates direct binding.
Z is —O—, —S—, a direct bond, —CO—, —SO ₂ —, —SO—, — (CH ₂ ) ₁ — (l is an integer of 1 to 10), or —C ( CH ₃ ) ₂ —.
R ¹¹ represents a direct bond, —O (CH ₂ ) _p —, —O (CF ₂ ) _p —, — (CH ₂ ) _p — or — (CF ₂ ) _p — (p is 1 to 12) Indicates an integer).
R ¹² and R ¹³ each independently represent a hydrogen atom, an alkali metal atom, an aliphatic hydrocarbon group, an alicyclic group, or a heterocyclic group containing oxygen. However, at least one of all R ¹² and R ¹³ included in the above formula is a hydrogen atom.
x ¹ is 0-4 integer. x ² is an integer of 1 to 5. a is an integer of 0 to 1. b shows the integer of 0-3.
As the structural unit having a proton conductive group represented by the formula (1), a structural unit represented by the following formula (1 ′ ″) is preferable.

(In the formula (1 ′ ″), Y is —CO—, —SO ₂ —, —SO—, —CONH—, —COO—, — (CF ₂ ) ₁ — (l is an integer of 1 to 10). ), At least one structure selected from the group consisting of —C (CF ₃ ) ₂ —, wherein Z is a direct bond, or — (CH ₂ ) ₁ — (l is an integer of 1 to 10), It represents at least one structure selected from the group consisting of —C (CH ₃ ) ₂ —, —O—, —S—, —CO—, —SO ₂ —, and Ar represents —SO ₃ H or —O ( CH ₂ ) represents an aromatic group having a substituent represented by _p SO ₃ H or —O (CF ₂ ) _p SO ₃ H. _p represents an integer of 1 to 12, and m represents an integer of 0 to 10. N represents an integer of 0 to 10, and k represents an integer of 1 to 4.) Among the single lines at the ends of the structural unit, those in which no substituent is displayed on one side are adjacent structural units It means of connection. ]
Here, m is preferably 0 or 1, n is preferably 0 or 1, and k is preferably 1.
Specific examples of the structural unit having a sulfonic acid group include the following.

  The polyarylene copolymer of the present invention has such an effect that a good proton conductivity is obtained by having such a structural unit having a sulfonic acid group together with a structural unit having a heterocyclic structure containing nitrogen. be able to.

[Structural units having a heterocyclic structure containing nitrogen]
The structural unit having a heterocyclic structure containing nitrogen is represented by the following general formula (2).

[In the formula (2), among the single wires at the end of the structural unit, one on which no substituent is displayed means connection with an adjacent structural unit. ]

Ar ³¹ represents a nitrogen-containing heterocyclic ring, specifically, pyrrole, 2H-pyrrole, imidazole, pyrazole, isothiazole, isoxazole, pyridine, pyrazine, pyrimidine, pyridazine, indolizine, isoindole, 3H-indole. , Indole, 1H-indazole, purine, 4H-quinolidine, quinoline, isoquinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, pteridine, carbazole, carboline, phenanthridine, acridine, perimidine, phenanthroline, phenazine, phenothiazine, furazane, phenoxy Sazine, pyrrolidine, pyrroline, imidazoline, imidazolidine, pyrazolidine, pyrazoline, piperidine, piperazine, indoline, isoindoline, quinuclidine, Is it a structure derived from at least one selected from the group consisting of xazole, benzoxazole, 1,3,5-triazine, bryne, tetrazole, tetrazine, triazole, phenalsazine, benzimidazole, benzotriazole, thiazole, benzothiazole, benzothiadiazole? ,
It contains at least one structure selected from the group consisting of structures represented by the following formulae.

[In the above formula, among the single wires at the ends of the structural units, those on which one or more substituents are not displayed mean connection with adjacent structural units. ]

  Among these, pyrrole, pyridine, pyrimidine, quinoline, isoquinoline, quinoxaline, phthalazine, naphthyridine, phenanthroline, phenazine, benzimidazole, benzotriazole, thiazole, benzothiadiazole, and structures represented by the following formulas are particularly preferable.

[In the above formula, among the single wires at the ends of the structural units, those on which one or more substituents are not displayed mean connection with adjacent structural units. ]

  When the polyarylene copolymer used in the present invention has a structural unit having a heterocyclic structure having nitrogen as described above together with a structural unit having an ion conductive group (sulfonic acid group) in the main chain, proton conduction It is preferable because the effect of suppressing the swelling in hot water and improving the heat resistance can be achieved without reducing the degree.

[Structural unit having aromatic structure]
Furthermore, the polyarylene-based copolymer used in the present invention may have a structural unit having an aromatic structure.
When such a polymer contains a structural unit having such an aromatic structure, the hydrophobicity of the polyarylene copolymer used in the present invention is remarkably improved. For this reason, since it can suppress the swelling in hot water and provide heat resistance, providing the proton conductivity similar to the past, it is preferable.
The structural unit having an aromatic structure is represented by the following formula (3).

In the above formula, Ar ²¹ , Ar ²² , Ar ²³ , and Ar ²⁴ each independently represent a divalent group having a benzene ring, condensed aromatic ring, or nitrogen-containing heterocyclic ring structure.
However, Ar ²¹ , Ar ²² , Ar ²³ , and Ar ²⁴ are such that some or all of the hydrogen atoms are fluorine-substituted, nitro, nitrile, or some or all of the hydrogen atoms are halogenated. It may be substituted with at least one atom or group selected from the group consisting of an alkyl group, an allyl group or an aryl group.
A and D are each independently a direct bond or —CO—, —SO ₂ —, —SO—, —CONH—, —COO—, — (CF ₂ ) ₁ — (l is an integer of 1 to 10; A), — (CH ₂ ) ₁ — (wherein 1 is an integer of 1 to 10), —CR ′ ₂ — (R ′ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group and a halogenated hydrocarbon group. ), Cyclohexylidene group, fluorenylidene group, -O- or S-
B is an oxygen atom or a sulfur atom. S and t each independently represent an integer of 0 to 4, and r represents 0 or an integer of 1 or more.
Among the single lines at the end of the structural unit, those not having a substituent displayed on one side mean connection with the adjacent structural unit.
Here, it is preferable that s and t are each independently an integer of 0 to 2.

  Specific examples of the structural unit having an aromatic structure include the following.

[Polyarylene copolymer]
The polyarylene copolymer of the present invention is represented by the following general formula (4).
The main chain in the present invention is a long chain portion in which repeating units are connected by polymerization, and the side chain is a portion that is branched from the main chain.

In the general formula (4), A, B, D, Y, Z, Ar ¹¹ , Ar ¹² , Ar ¹³ , Ar ^{21 to} Ar ²⁴ , Ar ³¹ , a, b, s, t, r, x ¹ , x ² And R ^{11 to} R ¹³ are A, B, D, Y, Z, Ar ¹¹ , Ar ¹² , Ar ¹³ , Ar ^{21 to} Ar ²⁴ , Ar ³¹ , a in the general formulas (1) to (3), respectively. , B, s, t, r, x ¹ , x ² and R ^{11 to} R ¹³ . x, y, and z indicate molar ratios when x + y + z = 100 mol%.

  The number of moles of the structural unit represented by the formula (1) possessed by 1 mole of the polyarylene copolymer used in the present invention is (x), and the number of moles of the structural unit represented by the formula (2) is (y). When the number of moles of the structural unit represented by formula (3) is (z), the value of (x) / {(x) + (y) + (z)} × 100 is preferably 0.05. It is -99.95, More preferably, it is 0.5-99.9, Most preferably, it is 1-90.

  The value of (y) / {(x) + (y) + (z)} × 100 is preferably 0.05 to 99.95, more preferably 0.1 to 99, and particularly preferably. Is 0.5-90.

  When the polyarylene copolymer of the present invention contains (y) in such an amount as the number of moles of the structural unit represented by the formula (2), the polymer electrolyte obtained from the polyarylene copolymer Is preferable because it is excellent in suppressing swelling and area change under hot water conditions and excellent in cross-linking resistance under high temperature conditions.

  Moreover, the ratio (y) / (x) of the structural unit represented by the formula (2) and the structural unit represented by the formula (1) is 0.01 to 20, preferably 0.1 to 15, more preferably. Is preferably 0.5 to 10. When the ratio of the structural unit represented by the formula (2) and the structural unit represented by the formula (1) is in the above range, the copolymer swells in hot water without decreasing the proton conductivity. Can be suppressed, and heat resistance can be improved.

  Further, the value of (z) / {(x) + (y) + (z)} × 100 is preferably 0 to 99.5, more preferably 0.01 to 99, and particularly preferably 0. .1 to 98.

The molecular weight of the polyarylene-based copolymer is 10,000 to 1,000,000, preferably 20,000 to 800,000, and more preferably 50,000 to 300,000 in terms of polystyrene-equivalent weight average molecular weight by gel permeation chromatography (GPC). .
The ion exchange capacity of the polyarylene copolymer is 0.5 to 3.5 meq / g, preferably 0.5 to 3.0 meq / g, more preferably 0.8 to 2.8 meq / g. . An ion exchange capacity of 0.5 meq / g or more is preferable because a polymer electrolyte having high proton conductivity and high power generation performance can be obtained. On the other hand, if it is 3.5 meq / g or less, it is preferable because sufficiently high water resistance can be provided.

  The above ion exchange capacity can be adjusted by changing the type, usage ratio, and combination of each structural unit. Therefore, it can be adjusted by changing the charge amount ratio and type of the precursor (monomer / oligomer) that induces the structural unit during polymerization.

  When the number of structural units containing sulfonic acid groups increases in the copolymer, the ion exchange capacity increases and proton conductivity increases, but the water resistance tends to decrease, whereas when these structural units decrease. The ion exchange capacity becomes small and the water resistance increases, but the proton conductivity tends to decrease.

[Polymer synthesis method]
The polyarylene copolymer of the present invention can be produced using, for example, the following three methods: A1, Method B1, and C1.

  (Method A1) For example, in the same manner as described in JP-A-2004-137444, a sulfonate ester serving as a structural unit having a sulfonic acid group and a monomer serving as a structural unit having a heterocyclic structure containing nitrogen If necessary, a monomer or oligomer that becomes a structural unit having an aromatic structure is copolymerized to produce a polyarylene-based copolymer having a sulfonate group, and this sulfonate group is deesterified, It can be synthesized by converting to a sulfonic acid group.

(1) Sulfonic acid ester to be a structural unit having a sulfonic acid group A structural unit having a sulfonic acid group is produced by polymerizing and using a sulfonic acid ester represented by the following formula (1 ′) as a raw material. be able to.

In the above formula (1 ′), Ar ¹¹ , Ar ¹² , and Ar ¹³ are each independently at least selected from the group consisting of a benzene ring, a condensed aromatic ring, and a nitrogen-containing heterocyclic ring that may be substituted with a fluorine atom. One type of structure is shown.
X represents at least one structure selected from the group consisting of chlorine, bromine, iodine, methanesulfonyl group, trifluoromethanesulfonyl group, benzenesulfonyl group, and toluenesulfonyl group.

Y represents —CO—, —SO ₂ —, —SO—, —CONH—, —COO—, — (CF ₂ ) _u — (u is an integer of 1 to 10), —C (CF ₃ ) _2. -Represents at least one structure selected from the group consisting of direct bonds.

Z is —O—, —S—, direct bond, —CO—, —SO ₂ —, —SO—, — (CH ₂ ) ₁ — (l is an integer of 1 to 10), —C (CH ₃ ) At least one structure selected from the group consisting of _2- .

R ¹¹ is at least one selected from the group consisting of a direct bond, —O (CH ₂ ) _p —, —O (CF ₂ ) _p —, — (CH ₂ ) _p —, and — (CF ₂ ) _p —. The structure is shown (p represents an integer of 1 to 12).

R ¹² and R ¹³ each independently represents at least one structure selected from the group consisting of a hydrogen atom, an alkali metal atom, an aliphatic hydrocarbon group, an alicyclic group, and a heterocyclic group containing oxygen. However, at least one of all R ¹² and R ¹³ included in the above formula is a hydrogen atom.
x ¹ is 0-4 integer. x ² is an integer of 1 to 5. y is an integer of 0-1. z shows the integer of 0-3.
The monomer represented by the above formula (1 ′) preferably has a structure represented by the following formula (1 ″).

[In the above formula (1 ″), X represents at least one structure selected from the group consisting of chlorine, bromine, iodine, methanesulfonyl group, trifluoromethanesulfonyl group, and benzenesulfonyl group.
Y represents —CO—, —SO ₂ —, —SO—, —CONH—, —COO—, — (CF ₂ ) ₁ — (l is an integer of 1 to 10), —C (CF ₃ ) ₂ —. At least one structure selected from the group consisting of: Z is a direct bond, or — (CH ₂ ) ₁ — (wherein 1 is an integer of 1 to 10), —C (CH ₃ ) ₂ —, — 1 represents at least one structure selected from the group consisting of O— and —S—, and Ar represents —SO ₃ H or —O (CH ₂ ) _p SO ₃ H or —O (CF ₂ ) _p SO ₃ H. The aromatic group which has a substituent represented is shown. p shows the integer of 1-12, m shows the integer of 0-10, n shows the integer of 0-10, k shows the integer of 1-4. ]
The sulfonic acid in the above formula may be a sulfonic acid ester. Examples of the ester include alkyl esters, aryl esters, cycloalkyl (which may be fluorine-substituted), and the like.

As a preferable combination of Y, Z, m, n, and k,
(1) A structure in which m = 1, n = 0, Y = —CO—, and Z = —O—.
(2) A structure in which m = 1, n = 1, k = 1, Y = —CO—, and Z = —O—.
(3) A structure in which m = 0, n = 1, k = 1, Y = —CO—, and Z = —O—.
(4) A structure in which m = 0, n = 1, k = 1, Y = —CO—, and Z is a direct bond,
(5) A structure in which m = 0, n = 0, and Y = —CO—.
(6) A structure in which m = 0, n = 0, and Y is a direct bond,
And so on.

  Specific examples of the compound represented by the general formula (1 ″) include compounds represented by the following general formula, Japanese Patent Application Laid-Open Nos. 2004-137444, 2004-345997, and 2004-346163. Mention may be made of the sulfonic acid esters described in the publication.

In these, the compound whose protecting group is neopentyl alcohol, isopropyl alcohol, and furfuryl alcohol is preferable.

The compound chlorine atom is replaced with a bromine atom in the compound, -CO- is -SO ₂ - can also be mentioned such compounds replaced. In addition, isomers having different bonding positions of chlorine atoms and bromine atoms can also be mentioned.

(2) Nitrogen-containing heterocyclic compound to be a structural unit having a nitrogen-containing heterocyclic structure In order to produce a polyarylene-based copolymer having a structural unit having a nitrogen-containing heterocyclic structure, for example, the following general formula (2 ′ ) Can be prepared and used.

Medium Ar ³¹ formula (2 ') has the same meaning as Ar ³¹ in the formula (2).

X represents an atom or group selected from halogen atoms excluding fluorine (chlorine, bromine, iodine) and —OSO ₂ Rb (where Rb represents an alkyl group, a fluorine-substituted alkyl group or an aryl group). Of these, chlorine and bromine are preferred.

Specific examples of the monomer represented by the above formula (2 ′) include the following.

  Moreover, the compound in which the chlorine atom replaced the bromine atom in the said compound, the compound in which the bromine atom was replaced by the chlorine atom, etc. are mentioned. In addition, isomers having different bonding positions of chlorine atoms and bromine atoms can also be mentioned.

(3) Compound having an aromatic structure to be a structural unit having an aromatic structure The structural unit having an aromatic structure is prepared, for example, by preparing an oligomer represented by the following general formula (3 ′) and polymerizing the oligomer. Can be obtained.

(In the formula (3 ′), Ar ²¹ , Ar ²² , Ar ²³ , and Ar ²⁴ represent at least one structure selected from the group consisting of a benzene ring, a condensed aromatic ring, and a nitrogen-containing heterocyclic ring, provided that Ar ²¹ , Ar ²² , Ar ²³ , and Ar ²⁴ , each hydrogen atom is substituted with a fluorine atom, an alkyl group, a halogenated alkyl group, an allyl group, an aryl group, a nitro group, or a nitrile group that is partially or completely substituted with fluorine May be.

  X represents at least one structure selected from the group consisting of chlorine, bromine, iodine, methanesulfonyl group, trifluoromethanesulfonyl group, benzenesulfonyl group, and toluenesulfonyl group.

A and D are independently a direct bond, or —CO—, —SO ₂ —, —SO—, —CONH—, —COO—, — (CF ₂ ) ₁ — (l is an integer of 1 to 10), — (CH ₂ ) ₁ — (wherein 1 is an integer of 1 to 10), —CR ′ ₂ — (R ′ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group and a halogenated hydrocarbon group), cyclohexane At least one structure selected from the group consisting of a silidene group, a fluorenylidene group, -O-, and -S-;
B is an oxygen atom or a sulfur atom independently, s, t show the integer of 0-4, r shows 0 or an integer greater than or equal to 1. )

  Moreover, the structural unit which has an aromatic structure is obtained by using the oligomer represented, for example by the following general formula (3 '') as a polymerization raw material of a polyarylene-type copolymer.

[In the above formula (3 ″), X represents at least one structure selected from the group consisting of chlorine, bromine, iodine, methanesulfonyl group, trifluoromethanesulfonyl group, benzenesulfonyl group, and toluenesulfonyl group.
A and D are independently a direct bond, or —CO—, —SO ₂ —, —SO—, —CONH—, —COO—, — (CF ₂ ) ₁ — (l is an integer of 1 to 10), — (CH ₂ ) ₁ — (wherein 1 is an integer of 1 to 10), —CR ′ ₂ — (R ′ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group and a halogenated hydrocarbon group), cyclohexane At least one structure selected from the group consisting of a silidene group, a fluorenylidene group, -O-, and -S-;
B is independently an oxygen atom or a sulfur atom,
R ^{1 to} R ¹⁶ may be the same as or different from each other, and are a hydrogen atom, a fluorine atom, an alkyl group, a halogenated alkyl group in which a part or all of them are halogenated, an allyl group, an aryl group, a nitro group, a nitrile group. At least one atom or group selected from the group consisting of
s and t represent an integer of 0 to 4, and r represents 0 or an integer of 1 or more. ]
Specific examples of the oligomer represented by the above formula (3 ″) include the following.

  Moreover, the compound etc. which the chlorine atom replaced the bromine atom in the said compound are mentioned. In addition, isomers having different bonding positions of chlorine atoms and bromine atoms can also be mentioned.

  The oligomer represented by the above formula (3 ″) can be produced, for example, by copolymerizing the following monomers. When r = 0 in the formula (3 ″), for example, 4,4′-dichlorobenzophenone. 4,4′-dichlorobenzanilide, 2,2-bis (4-chlorophenyl) difluoromethane, 2,2-bis (4-chlorophenyl) -1,1,1,3,3,3-hexafluoropropane, Examples include 4-chlorobenzoic acid-4-chlorophenyl ester, bis (4-chlorophenyl) sulfoxide, bis (4-chlorophenyl) sulfone, and 2,6-dichlorobenzonitrile.

  In these compounds, a compound in which a chlorine atom is replaced with a bromine atom or an iodine atom is exemplified. In the case of r = 1, for example, compounds described in JP-A No. 2003-113136 can be exemplified.

  In the case of r ≧ 2, for example, Japanese Patent Application Laid-Open No. 2004-137444, Japanese Patent Application Laid-Open No. 2004-244517, Japanese Patent Application No. 2003-143914 (Japanese Patent Application Laid-Open No. 2004-346164), Japanese Patent Application No. 2003-348523 (Japanese Patent Application Laid-Open No. 2005-348523). No. 112985), Japanese Patent Application No. 2003-348524, Japanese Patent Application No. 2004-211739 (Japanese Patent Application Laid-Open No. 2006-28414), Japanese Patent Application No. 2004- 211740 (Japanese Patent Application Laid-Open No. 2006-28415), and the like. Can do.

(4) Polymerization of polyarylene-based copolymer In order to obtain the desired polyarylene-based copolymer, first, a general formula (1) or a general formula (1 ′ ″) that can be a structural unit represented by the general formula (1 ′ ″) 1 ′) or (1 ″), a monomer represented by general formula (2 ′) that can be a structural unit represented by general formula (2), and, if necessary, general formula (3) ) Is copolymerized with a monomer or oligomer that can be a structural unit represented by formula (3 ′) or (3 ″) to obtain a precursor polyarylene. This copolymerization is carried out in the presence of a catalyst, and the catalyst used in this case is a catalyst system containing a transition metal compound. This catalyst system is (1) a transition metal salt and a ligand. A compound (hereinafter referred to as “ligand component”) or a transition metal complex coordinated with a ligand (including a copper salt) and (2) a reducing agent as essential components, and further increase the polymerization rate. Therefore, salts other than transition metal salts may be added.

  Here, transition metal salts include nickel compounds such as nickel chloride, nickel bromide, nickel iodide, nickel acetylacetonate, palladium compounds such as palladium chloride, palladium bromide, palladium iodide, iron chloride, iron bromide And iron compounds such as iron iodide and cobalt compounds such as cobalt chloride, cobalt bromide and cobalt iodide. Of these, nickel chloride, nickel bromide and the like are particularly preferable. The ligand component includes triphenylphosphine, tri (2-methyl) phenylphosphine, tri (3-methyl) phenylphosphine, tri (4-methyl) phenylphosphine, 2,2′-bipyridine, 1,5-cycloocta Examples include diene and 1,3-bis (diphenylphosphino) propane, but triphenylphosphine, tri (2-methyl) phenylphosphine, and 2,2′-bipyridine are preferable. The said ligand component can be used individually by 1 type or in combination of 2 or more types.

  Furthermore, as the transition metal (salt) in which the ligand is coordinated in advance, for example, nickel chloride bis (triphenylphosphine), nickel chloride bis (tri (2-methyl) phenylphosphine), nickel bromide bis (triphenyl) Phosphine), nickel iodide bis (triphenylphosphine), nickel nitrate bis (triphenylphosphine), nickel chloride (2,2′bipyridine), nickel bromide (2,2′bipyridine), nickel iodide (2,2) 'Bipyridine), nickel nitrate (2,2'bipyridine), bis (1,5-cyclooctadiene) nickel, tetrakis (triphenylphosphine) nickel, tetrakis (triphenylphosphite) nickel, tetrakis (triphenylphosphine) palladium Nickel chloride bis ( Triphenylphosphine), nickel chloride bis (tri (2-methyl) phenylphosphine), and nickel chloride (2,2′bipyridine) are preferred.

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

  Examples of salts other than transition metal salts that can be used in the catalyst system of the present invention include sodium compounds such as sodium fluoride, sodium chloride, sodium bromide, sodium iodide, sodium sulfate, potassium fluoride, and potassium chloride. Potassium compounds such as potassium bromide, potassium iodide, and potassium sulfate, and ammonium compounds such as tetraethylammonium fluoride, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide, and tetraethylammonium sulfate. Sodium, sodium iodide, potassium bromide, tetraethylammonium bromide and tetraethylammonium iodide are preferred.

  The proportion of each component used in the catalyst system is such that the transition metal salt or transition metal (salt) coordinated with a ligand is represented by the above general formula (1 ′) or (1 ″) and the general formula Usually, 0.0001 to 10 moles, preferably 0.01 to 0 moles per 1 mole in total of the compound represented by (2 ′) and the compound represented by the general formula (3 ′) or (3 ″). .5 moles. When the amount is less than 0.0001 mol, the polymerization reaction does not proceed sufficiently. On the other hand, when the amount exceeds 10 mol, there is a possibility that the molecular weight decreases. When a transition metal salt and a ligand component are used in the catalyst system, the ratio of the ligand component used is usually 0.1 to 100 mol, preferably 1 to 10 mol, per 1 mol of the transition metal salt. is there. If the amount is less than 0.1 mol, the catalytic activity becomes insufficient. On the other hand, if the amount exceeds 100 mol, the molecular weight may decrease.

  The ratio of the reducing agent used in the catalyst system is the compound represented by the general formula (1 ′) or (1 ″), the compound represented by the general formula (2 ′), and the general formula (3 ′). Or it is 0.1-100 mol normally with respect to 1 mol of total of the compound represented by (3 "), Preferably it is 1-10 mol. If the amount is less than 0.1 mol, the polymerization does not proceed sufficiently. On the other hand, if the amount exceeds 100 mol, purification of the resulting polymer may be difficult.

  Further, when a salt other than the transition metal salt is used in the catalyst system, the proportion of use is the general formula (1 ′) or (1) which can be a structural unit represented by the above general formula (1) or (1 ′ ″). 1 ″), a monomer represented by the general formula (2 ′) that can be a structural unit represented by the general formula (2), and a structural unit represented by the general formula (3). The amount of the monomer or oligomer is generally 0.001 to 100 mol, preferably 0.01 to 1 mol, based on 1 mol in total of the general formula (3 ′) or (3 ″). If it is less than 0.001 mol, the effect of increasing the polymerization rate may be insufficient. On the other hand, if it exceeds 100 mol, purification of the resulting polymer may be difficult.

  Examples of the polymerization solvent that can be used in the present invention include tetrahydrofuran, cyclohexanone, dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, 1-methyl-2-pyrrolidone, γ-butyrolactone, γ- Examples include butyrolactam, and tetrahydrofuran, N, N-dimethylformamide, N, N-dimethylacetamide, and 1-methyl-2-pyrrolidone are preferable. These polymerization solvents are preferably used after sufficiently dried. A monomer represented by the general formula (1 ′) or (1 ″) which can be a structural unit represented by the general formula (1) or (1 ′ ″) in the polymerization solvent, and the general formula (2) A monomer represented by the general formula (2 ′) that can be represented by the structural unit, and a monomer or oligomer that can be the structural unit represented by the general formula (3), that is, the general formula (3 ′) or (3 ″). ) Is generally 1 to 90% by weight, preferably 5 to 40% by weight.

  Moreover, the polymerization temperature at the time of superposing | polymerizing the polymer of this invention is 0-200 degreeC normally, Preferably it is 50-80 degreeC. The polymerization time is usually 0.5 to 100 hours, preferably 1 to 40 hours.

The above (Method A1) is a method of converting a sulfonic acid ester group to a sulfonic acid group (—SO ₃ H) by hydrolysis.
In particular,
(1) A method in which the polyarylene is added to an excess amount of water or alcohol containing a small amount of hydrochloric acid and stirred for 5 minutes or longer. (2) The polyarylene is heated at a temperature of about 80 to 120 ° C. in trifluoroacetic acid. Method of reacting for about 10 hours

(3) A sulfonate group (—SO ₃ R) in the polyarylene, and the polyarylene in the solution containing 1 to 9 times moles of lithium bromide with respect to 1 mole, for example, N-methylpyrrolidone. Examples include a method of adding hydrochloric acid after reacting at a temperature of about 150 ° C. for about 3 to 10 hours.

  (Method B1) For example, in the method described in JP-A-2001-342241, it has a skeleton represented by the above general formula (1 ′) or (1 ″) and does not have a sulfonic acid group or a sulfonic acid ester group. A monomer, a monomer represented by the general formula (2 ′) which can be a structural unit represented by the general formula (2), and a general formula (which can be a structural unit represented by the general formula (3) if necessary It can also be synthesized by copolymerizing the monomer or oligomer represented by 3 ′) or (3 ″) and sulfonating the polymer with a sulfonating agent (Method A2).

(Method C1) In the general formula (1 ′), when Ar is an aromatic group having a substituent represented by —O (CH ₂ ) _p SO ₃ H or —O (CF ₂ ) _p SO ₃ H Is, for example, a precursor monomer that can be a structural unit represented by the general formula (1) by the method described in Japanese Patent Application No. 2003-295974 (Japanese Patent Laid-Open No. 2005-60625), and the general formula (2 The monomer represented by the general formula (2 ′) that can be a structural unit represented by the formula (2) and the monomer or oligomer that can be a structural unit represented by the general formula (3) if necessary, It can also be synthesized by a method of introducing alkylsulfonic acid or fluorine-substituted alkylsulfonic acid into

In the case of direct sulfonation (Method B1),
Sulfonation can be carried out under known conditions using known sulfonating agents such as fuming sulfuric acid, chlorosulfonic acid, sulfuric acid, sodium hydrogen sulfite [Polymer Preprints, Japan, Vol. 42, no. 3, p. 730 (1993); Polymer Preprints, Japan, Vol. 42, no. 3, p. 736 (1994); Polymer Preprints, Japan, Vol. 42, no. 7, p. 2490-2492 (1993)]. That is, as the reaction conditions for the sulfonation, a precursor polyarylene having no sulfonic acid group or sulfonic acid ester group is reacted with the sulfonating agent in the absence of a solvent or in the presence of a solvent. Examples of the solvent include hydrocarbon solvents such as n-hexane, ether solvents such as tetrahydrofuran and dioxane, aprotic polar solvents such as dimethylacetamide, dimethylformamide, and dimethylsulfoxide, tetrachloroethane, dichloroethane, chloroform, and chloride. And halogenated hydrocarbons such as methylene. The reaction temperature is not particularly limited, but is usually −50 to 200 ° C., preferably −10 to 100 ° C. Moreover, reaction time is 0.5 to 1,000 hours normally, Preferably it is 1 to 200 hours.

  (Method C1) is a monomer having a skeleton represented by the general formula (1 ′) or (1 ″) and having no sulfonic acid group or sulfonic acid ester group and having an OH group or SH at the terminal (The following formulas (3′a), (3′b), (3′-1)) and a monomer represented by the general formula (2 ′) that can be a structural unit represented by the above general formula (2) If necessary, after copolymerization with a monomer or oligomer represented by the general formula (3 ′) or (3 ″) that can be a structural unit represented by the general formula (3), an —OH group or —SH Substituting a group with -OM group or -SM group (M represents a hydrogen atom or an alkali metal atom), and reacting a compound represented by the following general formula (5) or (6) under alkaline conditions Can be sulfonated.

Formula (3'a), (3'b) in, X, Y, Z, Ar 11, Ar 12, Ar 13 is, X in each of the above general formula (1 '), Y, Z , Ar 11, Ar 12 And Ar ¹³ , a is an integer of 0 to 1, and b is an integer of 0 to 3. In the formula (3′-1), X, Y, Z, m, n, and k are respectively synonymous with X, Y, Z, m, n, and k in the general formula (1 ″), and X ′ is OH or SH group is represented, and Ar ″ represents an aromatic group having an OH or SH group.

In the formulas (5) and (6), R ⁴⁰ represents at least one atom or group selected from the group consisting of a hydrogen atom, a fluorine atom, an alkyl group, and a fluorine-substituted alkyl group, and g is an integer of 1 to 20 Indicates.

  In formula (6), L represents any of a chlorine atom, a bromine atom, and an iodine atom, and M represents a hydrogen atom or an alkali metal atom.

[Method of manufacturing electrolyte membrane]
The sulfonic acid-containing polyarylene copolymer of the present invention comprises the above-mentioned copolymer, and is an electrolyte for a primary battery, an electrolyte for a secondary battery, a polymer solid electrolyte for a fuel cell, a display element, various sensors, a signal transmission medium, When used for solid capacitors, ion exchange membranes, etc., it may be used in a membrane state, a solution state, or a powder state. Among these, a membrane state and a solution state are preferable (hereinafter, the membrane state is referred to as a polymer electrolyte). Called membrane).

  The polymer electrolyte membrane of the present invention can be produced by a casting method or the like in which the sulfonic acid-containing polyarylene copolymer is mixed in an organic solvent and cast on a substrate to form a film. . Here, the substrate is not particularly limited as long as it is a substrate used in a normal solution casting method. For example, a substrate made of plastic, metal, or the like is used, and preferably a heat treatment such as a polyethylene terephthalate (PET) film. A substrate made of a plastic resin is used.

  The solvent for mixing the sulfonic acid-containing polyarylene copolymer may be any solvent that dissolves the copolymer or a solvent that swells, such as N-methyl-2-pyrrolidone, N, N-dimethylformamide, Aprotic polar solvents such as γ-butyrolactone, N, N-dimethylacetamide, dimethylsulfoxide, dimethylurea, dimethylimidazolidinone and acetonitrile, and chlorine-based solvents such as dichloromethane, chloroform, 1,2-dichloroethane, chlorobenzene and dichlorobenzene Solvents, methanol, ethanol, propanol, iso-propyl alcohol, sec-butyl alcohol, tert-butyl alcohol and other alcohols, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene Alkylene glycol monoalkyl ethers such as glycol monoethyl ether, acetone, methyl ethyl ketone, cyclohexanone, ketones such as γ- butyrolactone, tetrahydrofuran, solvents such as ethers 1,3-dioxane and the like. These solvents can be used alone or in combination of two or more. In particular, N-methyl-2-pyrrolidone (hereinafter also referred to as “NMP”) is preferable in terms of solubility and solution viscosity.

  When a mixture of an aprotic polar solvent and another solvent is used as the solvent, the composition of the mixture is 95 to 25% by weight of the aprotic polar solvent, preferably 90 to 25% by weight, The solvent is 5 to 75% by weight, preferably 10 to 75% by weight (however, the total is 100% by weight). When the amount of the other solvent is within the above range, the effect of lowering the solution viscosity is excellent. In this case, the combination of the aprotic polar solvent and the other solvent is preferably NMP as the aprotic polar solvent and methanol having an effect of lowering the solution viscosity in a wide composition range as the other solvent.

  The polymer concentration of the solution in which the copolymer and the additive are dissolved depends on the molecular weight of the sulfonic acid-containing polyarylene copolymer, but is usually 5 to 40% by weight, preferably 7 to 25% by weight. is there. If it is less than 5% by weight, it is difficult to form a thick film, and pinholes are easily generated. On the other hand, if it exceeds 40% by weight, the solution viscosity is so high that it is difficult to form a film, and surface smoothness may be lacking.

  The solution viscosity is usually 2,000 to 100,000 mPa · s, preferably 3,000, although it depends on the molecular weight, polymer concentration, and additive concentration of the sulfonic acid-containing polyarylene copolymer. ˜50,000 mPa · s. If it is less than 2,000 mPa · s, the retention of the solution during film formation is poor and it may flow from the substrate. On the other hand, if it exceeds 100,000 mPa · s, the viscosity is too high to be extruded from the die, and it may be difficult to form a film by the casting method.

  After film formation as described above, when the obtained undried film is immersed in water, the organic solvent in the undried film can be replaced with water, and the amount of residual solvent in the resulting polymer electrolyte membrane is reduced. can do.

  In addition, after film formation, before immersing an undried film in water, you may predry an undried film. The preliminary drying is performed by holding the undried film at a temperature of usually 50 to 150 ° C. for 0.1 to 10 hours.

  When the undried film is immersed in water and dried as described above, a film with a reduced amount of residual solvent is obtained. The residual solvent amount of the film thus obtained is usually 5% by weight or less. Further, depending on the dipping conditions, the amount of residual solvent in the obtained film can be set to 1% by weight or less. As such conditions, for example, the amount of water used relative to 1 part by weight of the undried film is 50 parts by weight or more, the temperature of the water when immersed is 10 to 60 ° C., and the immersion time is 10 minutes to 10 hours. is there.

After immersing the undried film in water as described above, the film is dried at 30-100 ° C, preferably 50-80 ° C, for 10-180 minutes, preferably 15-60 minutes, and then at 50-150 ° C. The film can be obtained by vacuum drying under reduced pressure of 500 mmHg to 0.1 mmHg for 0.5 to 24 hours.
The polymer electrolyte membrane obtained by the method of the present invention has a dry film thickness of usually 10 to 100 μm, preferably 20 to 80 μm.

  In addition, by forming the polyarylene copolymer having the sulfonic acid ester group or the alkali metal salt of sulfonic acid into a film by the above-described method, and then performing an appropriate post-treatment such as hydrolysis or acid treatment. The polymer electrolyte membrane according to the present invention can also be produced. Specifically, a polyarylene copolymer having an alkali metal salt of a sulfonic acid is formed into a film by the method described above, and then the membrane is hydrolyzed or acid-treated to thereby obtain a sulfonic acid group-containing polymer. A polymer electrolyte membrane made of an arylene copolymer can be produced.

In addition, when producing a polymer electrolyte membrane, in addition to the sulfonic acid group-containing polyarylene copolymer, inorganic acids such as sulfuric acid and phosphoric acid, phosphoric acid glass, tungstic acid, phosphate hydrate, β-alumina Inorganic proton conductor particles such as proton-substituted products and proton-introduced oxides, organic acids containing carboxylic acids, organic acids containing sulfonic acids, organic acids containing phosphonic acids, and appropriate amounts of water may be used in combination.
[Example]

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples. In Examples, “%” means “% by weight” unless otherwise specified.

[Preparation of electrolyte membrane for evaluation]
After the copolymer obtained in each Example / Comparative Example was dissolved in an N-methylpyrrolidone / methanol solution, it was cast on a PET substrate using an applicator, and 60 ° C. × 30 minutes, 80 ° C. using an oven. × 40 minutes, 120 ° C. × 60 minutes. The dried membrane was immersed in deionized water. After immersion, a film for evaluation was obtained by drying at 50 ° C. for 45 minutes.

[Molecular weight]
The copolymer obtained in each Example / Comparative Example was dissolved in an N-methylpyrrolidone buffer solution (hereinafter referred to as NMP buffer solution), and subjected to gel permeation chromatography (GPC) to obtain a polystyrene-equivalent number average molecular weight ( Mn) and weight average molecular weight (Mw) were determined. The NMP buffer solution was adjusted at a ratio of NMP (3 L) / phosphoric acid (3.3 mL) / lithium bromide (7.83 g).

[Equivalent of sulfonic acid group]
The resulting sulfonated polymer was washed with distilled water until the washing water became neutral to remove free remaining acid, and then dried. Thereafter, a predetermined amount is weighed, dissolved in a mixed solvent of THF / water, titrated with a standard solution of NaOH using phenolphthalein as an indicator, and the equivalent of sulfonic acid groups (ion exchange capacity) from the neutral point. (Meq / g) was determined.

[Hot water test]
The film was cut into 2.0 cm × 3.0 cm and weighed to obtain a test piece for testing. After conditioning under conditions of 24 ° C. and 50% relative humidity (RH), this film is put into a polycarbonate 250 ml bottle, about 100 ml of distilled water is added thereto, and a pressure cooker tester (manufactured by HIRAYAMA MFS CORP) is used. And PC-242HS) for 24 hours at 120 ° C. After completion of the test, each film was taken out from the hot water, the surface water was gently wiped off with a Kimwipe, and the water content was weighed to determine the water content. Moreover, the dimension of the film was measured and the swelling rate was calculated | required. Furthermore, this membrane was conditioned at 24 ° C. and RH 50%, water was distilled off, the weight after the hot water test was weighed, and the weight residual ratio was determined.

[Measurement of proton conductivity]
The AC resistance was obtained by pressing a platinum wire (f = 0.5 mm) on the surface of a strip-shaped sample film having a width of 5 mm, holding the sample in a constant temperature and humidity device, and measuring AC impedance between the platinum wires. . That is, the impedance at AC 10 kHz was measured in an environment of 85 ° C. and relative humidity 90%. A chemical impedance measurement system manufactured by NF Circuit Design Block Co., Ltd. was used as the resistance measuring device, and JW241 manufactured by Yamato Scientific Co., Ltd. was used as the constant temperature and humidity device. Five platinum wires were pressed at intervals of 5 mm, the distance between the wires was changed to 5 to 20 mm, and the AC resistance was measured. The specific resistance of the membrane was calculated from the line-to-line distance and the resistance gradient, and the proton conductivity was calculated from the reciprocal of the specific resistance.
Specific resistance R (Ω · cm) = 0.5 (cm) × film thickness (cm) × resistance-to-resistance gradient (Ω / cm)

[Heat resistance test]
A film cut to 2 cm × 3 cm was sandwiched between bencots, placed in a crow sample tube, and heated in a compact precision thermostat (AWC-2) at 160 ° C. for 24 hours under air conditions. The heated film was dissolved in NMP buffer solvent at a concentration of 0.2 wt%, and the molecular weight and area area (A24) were determined by GPC (NMP buffer solvent) (manufactured by Tosoh Corporation HCL-8220). The film before heating was also measured under the same conditions to obtain the molecular weight and area area (A0), and the change in molecular weight and the insoluble fraction were obtained from the following formula. When the insolubility rate increases, the cross-linking resistance of the film is inferior.
Insoluble rate (%) = (A24−A0) / (A0)
The NMP buffer solution was adjusted at a ratio of NMP (3 L) / phosphoric acid (3.3 mL) / lithium bromide (7.83 g).

<Nitrogen-containing heterocycle>
As nitrogen-containing heterocycles, 2,5-dichloropyridine (manufactured by Tokyo Chemical Industry), 2,5-dibromopyrimidine (non-patent document 1), 5,5′-dibromo-2,2′-bipyridine (non-patent document 2) 5,8-dibromoquinoline (Non-patent document 3), 2,6-dichloroquinoline (Non-patent document 4), 2,6-dichloro-1,5-naphthyridine, 2,2′-dichloro-6,6′- Biquinoline (Non-patent document 5), 5,8-quinoxaline, and 2,6-quinoxaline (Non-patent document 6) were used as examples.

Non-Patent Document 1 Chem. Lett. , 583-586 (1992).
Non-Patent Document 2 Chem. Lett. , 223 (1990).
Non-Patent Document 3 Macromolecules, 24, 5883-5858 (1991).
Non-Patent Document 4 Macromolecules, 27, 756-761 (1994).
Non-Patent Document 5 Macromolecules, 28, 4260-4267 (1995).
Non-Patent Document 6 Am. Chem. Soc. , 118, 3930-3937 (1996).

<Synthesis of a structural unit having a sulfonic acid group>
Chlorosulfonic acid (233.0 g, 2 mol) was added to a 3 L three-necked flask equipped with a stirrer and a condenser, followed by 2,5-dichlorobenzophenone (100.4 g, 400 mmol), and an oil bath at 100 ° C. The reaction was allowed for 8 hours. After a predetermined time, the reaction solution was slowly poured onto crushed ice (1000 g) and extracted with ethyl acetate. The organic layer was washed with brine and dried over magnesium sulfate, and then ethyl acetate was distilled off to obtain pale yellow crude crystals (3- (2,5-dichlorobenzoyl) benzenesulfonic acid chloride). The crude crystals were used in the next step without purification.

  2,2-Dimethyl-1-propanol (neopentyl alcohol) (38.8 g, 440 mmol) was added to 300 ml of pyridine and cooled to about 10 ° C. The crude crystals obtained above were gradually added thereto over about 30 minutes. After the total amount was added, the reaction was further stirred for 30 minutes. After the reaction, the reaction solution was poured into 1000 ml of aqueous hydrochloric acid, and the precipitated solid was collected. The obtained solid was dissolved in ethyl acetate, washed with aqueous sodium hydrogen carbonate solution and brine, dried over magnesium sulfate, and then ethyl acetate was distilled off to obtain crude crystals. This was recrystallized with methanol to obtain white crystals of neopentyl 3- (2,5-dichlorobenzoyl) benzenesulfonate (30-1), which was the target product.

<Synthesis of a structural unit having an aromatic structure>
To a 1 L three-necked flask equipped with a stirrer, thermometer, Dean-stark tube, nitrogen inlet tube, and condenser tube, 154.8 g (0.9 mol) of 2,6-dichlorobenzonitrile and 2,2-bis (4-hydroxy) were added. (Phenyl) -1,1,1,3,3,3-hexafluoropropane (269.0 g, 0.8 mol) and potassium carbonate (143.7 g, 1.04 mol) were weighed. After substitution with nitrogen, 1020 mL of sulfolane and 510 mL of toluene were added and stirred. The reaction solution was heated to reflux at 150 ° C. in an oil bath. Water produced by the reaction was trapped in a Dean-stark tube. After 3 hours, when almost no water was observed, toluene was removed from the Dean-stark tube out of the system. The reaction temperature was gradually raised to 200 ° C. and stirring was continued for 3 hours. Then, 51.6 g (0.3 mol) of 2,6-dichlorobenzonitrile was added, and the reaction was further continued for 5 hours.

  The reaction solution was allowed to cool and then diluted by adding 250 mL of toluene. Inorganic salts insoluble in the reaction solution were filtered, and the filtrate was poured into 8 L of methanol to precipitate the product. The precipitated product was filtered and dried, then dissolved in 500 mL of tetrahydrofuran, and poured into 5 L of methanol for reprecipitation. The precipitated white powder was filtered and dried to obtain 258 g of the desired product. Mn measured by GPC was 8,200. It was confirmed that the obtained compound was an oligomer represented by the formula (30-2).

[Example 1]
19.06 g (47.5 mmol) of the compound represented by the above (30-1), 0.25 g (1.7 mmol) of 2,5-dichloropyridine, and the compound represented by the above (30-2). 40 g (0.8 mmol), bis (triphenylphosphine) nickel dichloride 1.31 g (2.0 mmol), triphenylphosphine 3.93 g (15 mmol), sodium iodide 0.22 g (1.5 mmol), zinc 7.84 g 85 mL of dry dimethylacetamide (DMAc) in a mixture of (120 mmol) was added under nitrogen.

The reaction system was heated with stirring (finally heated to 79 ° C.) and reacted for 3 hours. An increase in viscosity in the system was observed during the reaction. The polymerization reaction solution was diluted with 193 mL of DMAc, stirred for 30 minutes, and filtered using Celite as a filter aid.
Lithium bromide (13.27 g, 153 mmol) was added to the filtrate and reacted at an internal temperature of 120 ° C. for 7 hours under a nitrogen atmosphere. After the reaction, the mixture was cooled to room temperature, poured into 1.5 L of water and solidified. The coagulum was immersed in acetone, filtered and washed. The washed product was washed while being stirred with 370 g of 1N sulfuric acid. After filtration, the product was washed with ion exchanged water until the pH of the washing solution became 5 or higher. As a result of measuring the molecular weight of the obtained polymer by GPC, the ion exchange capacity is shown in Table 1. The obtained polymer was the following general formula (30-3).

[Examples 2 to 9]
A polymer was obtained in the same manner as in Example 1 except that a nitrogen-containing heterocycle as shown in Table 1 was used and the charge ratio was used at a ratio as shown in Table 1. As a result of measuring the molecular weight of the obtained polymer by GPC, the ion exchange capacity is shown in Table 1.

[Comparative Example 1]
<Polymer synthesis>
19.66 g (49.0 mmol) of the compound represented by the above (30-1), 8.20 g (1.0 mmol) of the compound represented by the above (30-2), bis (triphenylphosphine) nickel dichloride 1 In a mixture of .31 g (2.0 mmol), triphenylphosphine 3.93 g (15 mmol), sodium iodide 0.22 g (1.5 mmol), zinc 7.84 g (120 mmol), 92 mL of dried DMAc was added under nitrogen. .

The reaction system was heated with stirring (finally heated to 79 ° C.) and reacted for 3 hours. An increase in viscosity in the system was observed during the reaction. The polymerization reaction solution was diluted with 193 mL of DMAc, stirred for 30 minutes, and filtered using Celite as a filter aid.
To the filtrate, 12.77 g (147 mmol) of lithium bromide was added and reacted at an internal temperature of 120 ° C. for 7 hours under a nitrogen atmosphere. After the reaction, the mixture was cooled to room temperature, poured into 1.5 L of water and solidified. The coagulum was immersed in acetone, filtered and washed. The washed product was washed while being stirred with 370 g of 1N sulfuric acid. After filtration, the product was washed with ion exchanged water until the pH of the washing solution became 5 or higher. As a result of measuring the molecular weight of the obtained polymer by GPC, the ion exchange capacity is shown in Table 1. The obtained polymer was the following general formula (30-4).

[Comparative Example 2]
19.26 g (48.0 mmol) of the compound represented by (30-1) above, 0.35 g (1.1 mol) of the compound represented by (30-5), represented by (30-2) above Compound 7.38 g (0.9 mmol), bis (triphenylphosphine) nickel dichloride 1.31 g (2.0 mmol), triphenylphosphine 3.93 g (15 mmol), sodium iodide 0.22 g (1.5 mmol), zinc 89 mL of dry DMAc in 7.84 g (120 mmol) of the mixture was added under nitrogen.

The reaction system was heated with stirring (finally heated to 79 ° C.) and reacted for 3 hours. An increase in viscosity in the system was observed during the reaction. The polymerization reaction solution was diluted with 193 mL of DMAc, stirred for 30 minutes, and filtered using Celite as a filter aid.
Lithium bromide (13.08 g, 150.6 mmol) was added to the filtrate and reacted at an internal temperature of 120 ° C. for 7 hours under a nitrogen atmosphere. After the reaction, the mixture was cooled to room temperature, poured into 1.5 L of water and solidified. The coagulum was immersed in acetone, filtered and washed. The washed product was washed while being stirred with 370 g of 1N sulfuric acid. After filtration, the product was washed with ion exchanged water until the pH of the washing solution became 5 or higher. As a result of measuring the molecular weight of the obtained polymer by GPC, the ion exchange capacity is shown in Table 1. The obtained polymer was the following general formula (30-6).

  By introducing a heterocyclic ring containing nitrogen into the main chain of the polyarylene copolymer, the proton conductivity is equivalent, and it is possible to suppress the moisture content and area change in the hydrothermal test relative to Comparative Example 1. . In addition, crosslinking resistance in the heat test is higher when a nitrogen-containing heterocycle is introduced.

  When comparing Examples 1 to 9 and Comparative Example 2, it is more heat-resistant to introduce a nitrogen-containing heterocycle into the main chain than to introduce a nitrogen-containing heterocycle into the side chain of the polyarylene copolymer. It becomes possible to suppress the moisture content and area change in the water test.

Claims (4)

The main chain contains a structural unit having a proton conductive group represented by the following general formula (1) and having a heterocyclic structure containing nitrogen represented by the following general formula (2). A polyarylene copolymer characterized by the above.
[In formula (1), Y represents _{-CO -, - SO 2 -,} - SO-, a direct _{bond, - (CF 2) u -} (u is an integer of 1 to 10), - C (CF _{3) 2} represents at least one structure selected from the group consisting of —, Z is a direct bond, or — (CH ₂ ) ₁ — (l is an integer of 1 to 10), —C (CH ₃ ) ₂ —. , -O -, - represents at least one structure selected from the group consisting of S-, Ar is -SO ₃ H or _{-O (CH 2) p SO 3} H or -O (CF _{2) p} SO ₃ An aromatic group having a substituent represented by H is shown. p shows the integer of 1-12, m shows the integer of 0-3, n shows the integer of 0-3, k shows the integer of 1-4. Among the single lines at the end of the structural unit, those not having a substituent displayed on one side mean connection with the adjacent structural unit. ]
[In the formula (2), the single line at the end of the structural unit means that it is directly connected to the aromatic ring .
Ar ³¹ is pyrrole, 2H-pyrrole, imidazole, pyrazole, isothiazole, isoxazole, pyridine, pyrazine, pyrimidine, pyridazine, indolizine, isoindole, 3H-indole, indole, 1H-indazole, purine, 4H-quinolidine, Quinoline, isoquinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, pteridine, carbazole, carboline, phenanthridine, acridine, perimidine, phenanthroline, phenazine, phenothiazine, furan, phenoxazine, pyrrolidine, pyrroline, imidazoline, imidazolidine, pyrazolidine Pyrazoline, piperidine, piperazine, indoline, isoindoline, quinuclidine, oxazole, 1,3,5-triazine Brin, tetrazole, tetrazine, triazole, phenarsazine, benzotriazole, thiazole, or structure derived from at least one selected from the group consisting of benzothiadiazole,
Or the structure containing at least 1 sort (s) of structure chosen from the group which consists of a structure represented by a following formula is shown.
In the above formula, among the single wires at the ends of the structural units, those on which no substituent is displayed indicate connection with the adjacent structural units. ] The polyarylene copolymer according to claim 1, wherein the polyarylene copolymer includes a structural unit having an aromatic structure represented by the following general formula (3).
[In the formula (3), A and D are independently a direct bond, or —CO—, —SO ₂ —, —SO—, — (CF ₂ ) ₁ — (l is an integer of 1 to 10), (CH ₂ ) _l — (l is an integer of 1 to 10), —CR ′ ₂ — (R ′ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group and a halogenated hydrocarbon group), cyclohexylene 1 represents at least one structure selected from the group consisting of a den group, a fluorenylidene group, —O—, and —S—, B is an oxygen atom or a sulfur atom independently, and R ^{1 to} R ¹⁶ are the same as each other May be different, at least selected from the group consisting of a hydrogen atom, a fluorine atom, a nitro group, a nitrile group, or an alkyl group, an allyl group, or an aryl group in which some or all of the hydrogen atoms may be fluorine-substituted. One atom or group is shown. s and t represent an integer of 0 to 4, and r represents 0 or an integer of 1 or more. ]   A polymer electrolyte comprising the polyarylene-based copolymer according to claim 1.   The polymer electrolyte comprising the polyarylene copolymer according to any one of claims 1 to 2, having an ion exchange capacity of 0.5 to 3.5 meq / g.