JP2021039950A - Binder for fuel cell - Google Patents

Abstract

To provide a high-performance catalyst and binder.SOLUTION: Provided are a catalyst containing calcined polyaniline containing phosphonic acid residues and a binder for a fuel cell. By using the catalyst containing the calcined polyaniline phosphonic acid, a positive electrode catalyst with catalytic activity is provided at a low cost and easily without use of conventional catalysts such as platinum. The polyaniline phosphonic acid can also be used as a halogen-free binder for electrode formation in a fuel cell. The present invention also provides a fuel cell using the catalyst or binder.SELECTED DRAWING: None

Description

The present invention relates to catalysts and binders, especially catalysts and binders for fuel cells. In one aspect, the present invention relates to a positive electrode catalyst for a fuel cell containing polyaniline phosphonic acid or a calcined product thereof, which has oxygen reduction properties.

The present invention also relates to a polymer electrolyte fuel cell (PEFC). In one aspect, the present invention relates to electrodes used in PEFC. In one aspect, the present invention relates to a binder used for an electrode layer used in PEFC.

In recent years, environmental pollution caused by thermal power generation, hydroelectric power generation, or nuclear power generation, which are sources of electric energy, has become a serious problem. Therefore, attention is being paid to the development of a fuel cell capable of extracting electric energy from hydrogen energy. Hydrogen is obtained by decomposing water and hydrocarbon compounds, and the chemical energy contained in the unit weight is large. Further, water is produced by the oxidation reaction of hydrogen gas, and has an advantage that it does not generate _{harmful substances or CO 2 which is a global warming gas.}

In a polymer electrolyte fuel cell (PEFC) that uses hydrogen gas as the negative electrode fuel and oxygen gas as the positive electrode fuel, Pt is used as a catalyst for the oxidation reaction of hydrogen gas and the reduction reaction of oxygen gas. On the Pt catalyst, the oxidation reaction of hydrogen gas proceeds rapidly at room temperature. However, on the Pt catalyst, the reduction reaction of oxygen gas has a larger activation energy than the oxidation reaction of hydrogen gas, which is a major factor in lowering the voltage of PEFC. Therefore, the challenge of catalyst materials used in PEFC is the development of catalyst materials with high oxygen reduction reaction activity.

For example, Patent Document 1 below discloses an electrode for a fuel cell in which fine metal particles such as platinum are dispersed and supported on the surface wall of pores of a porous carbon film. However, in the conventional techniques such as Patent Document 1 below, since expensive platinum is used as a catalyst, there is a problem that the cost is high. Therefore, Patent Document 2 below discloses an electrode for a fuel cell using nitrogen-containing graphite. Further, Non-Patent Document 1 below discloses an electrode for a fuel cell in which a three-dimensional network structure is formed by doping polyaniline with salicylic acid. The method of Non-Patent Document 1 has a drawback that it requires a lot of labor and time because it includes a step of recrystallization and washing of NaCl. Therefore, a catalyst that can be manufactured more easily is desired.

Further, not limited to the electrode material for batteries, if a reduction reaction active catalyst having a high catalytic activity can be realized, the efficiency of the reduction reaction currently used in various fields can be improved. For example, it is considered that it can be used for carbon dioxide reduction reaction.

Further, in a binder for a fuel cell, a resin containing halogen is often used, and a resin containing no halogen has been required to achieve the performance of the binder.

Further, it is considered that high proton conductivity, electrical conductivity, and oxygen permeability are important for binders for fuel cells. Currently, Nafion, which is widely used as a binder for fuel cells, is an insulator. Therefore, if a catalyst that is wrapped in naphthion and isolated from the electrode is generated, the catalyst utilization rate will be lowered. It is thought that such a problem can be solved if there is a binder that imparts electrical conductivity in addition to proton conductivity.

Japanese Unexamined Patent Publication No. 2004-335459 Japanese Unexamined Patent Publication No. 2013-202430

J. Am. Chem. Soc. 2015, 137, 5414-5420.

However, Patent Document 2 and Non-Patent Document 1 require synthesis under severe conditions or long-term synthesis using a strong acid for the synthesis of the catalyst, although the expensive platinum is not used as a catalyst. Therefore, the present invention is to provide an oxygen reduction reaction active catalyst having a high catalytic activity that can be easily synthesized without using an expensive catalytic metal such as platinum, and a fuel cell using the same.

As a result of intensive studies, the present inventors have found that the above-mentioned problems can be achieved by using a catalyst characterized by containing a polyaniline having a specific structure or a calcined product thereof, and have completed the present invention. ..

For example, the present invention provides the following catalysts and the like.

(Item 1)
A catalyst for promoting the reduction reaction
The following general formula (1):
-(A ¹ ) _k- (1)
Including polyaniline represented by or a calcined product thereof, where
A ¹ is an independently substituted or unsubstituted aniline monomer residue.
Each of A ¹ has m phosphonic acid residues R ^p and n substituents R independently.
The phosphonic acid residue R ^p is expressed by the following formula:

During the ceremony
M ¹ and M ² are independently hydrogen atoms, alkyl groups having 1 to 15 carbon atoms, aralkyl groups having 7 to 34 carbon atoms, aryl groups having 6 to 30 carbon atoms, alkali metals, and alkaline earth metals. At least one selected from the group consisting of an ammonium group and a pyridinium group.
M ¹ and M ² may be the same or different,
If one of the M ¹ or M ² is an alkaline earth metal, one of the two O in R ^p groups ^- one of M ¹ or M ² have the said alkaline earth metal atom is bonded The structure is such that the other of the above does not exist, or the structure is such that the alkaline earth metal atom bridges the O ^{− of two R p groups.}
R is an independently halogen atom, an alkyl group having 1 to 15 carbon atoms, an aralkyl group having 7 to 34 carbon atoms, an alkoxy group having 1 to 15 carbon atoms, and an alkylthio group having 1 to 15 carbon atoms. It is at least one selected from the group consisting of an alkylamino group having 1 to 15 carbon atoms, a carboxyl group, a carboxylic acid ester group having 1 to 15 carbon atoms in the ester residue, a nitro group and a cyano group.
m is an integer of 1 to 4 independently,
n is an integer of 0 to 3 independently.
The sum of m and n is 4 or less independently for each aniline monomer residue.
k is an integer from 4 to 3000,
catalyst.

(Item 2)
Item 2. The catalyst according to Item 1, further comprising a bipyridine compound.

(Item 3)
Item 2. The catalyst according to Item 1 or 2, further comprising a compound of iron, cobalt, or nickel.

(Item 4)
The catalyst according to any one of Items 1 to 3 above, which comprises a calcined product of the polyaniline.

(Item 5)
Item 4. The catalyst according to Item 4, wherein the fired body is fired at a temperature of 700 ° C. or higher.

(Item 6)
The catalyst according to any one of the above items 1 to 5, which is characterized by promoting an oxygen reduction reaction.

(Item 7)
The catalyst according to any one of Items 1 to 6, wherein the oxygen reduction reaction at the positive electrode of the fuel cell is promoted.

(Item 8)
The catalyst according to any one of Items 1 to 7, wherein the number of phosphonic acid residues introduced into the polyaniline is 10% or more with respect to the number of aniline monomer residues.

(Item 9)
A fuel cell comprising the catalyst according to any one of the above items 1 to 8 in the positive electrode.

(Item 10)
The following general formula (1):
-(A ¹ ) _k- (1)
It is a binder for polymer electrolyte fuel cells containing polyaniline represented by, and here,
A ¹ is an independently substituted or unsubstituted aniline monomer residue.
Each of A ¹ has m phosphonic acid residues R ^p and n substituents R independently.
The phosphonic acid residue R ^p is expressed by the following formula:

During the ceremony
M ¹ and M ² are independently hydrogen atoms, alkyl groups having 1 to 15 carbon atoms, aralkyl groups having 7 to 34 carbon atoms, aryl groups having 6 to 30 carbon atoms, alkali metals, and alkaline earth metals. At least one selected from the group consisting of an ammonium group and a pyridinium group.
M ¹ and M ² may be the same or different,
However, at least one M ^{1 in the} polyaniline is a hydrogen atom.
If one of the M ¹ or M ² is an alkaline earth metal, one of the two O in R ^p groups ^- one of M ¹ or M ² have the said alkaline earth metal atom is bonded The structure is such that the other of the above does not exist, or the structure is such that the alkaline earth metal atom bridges the O ^{− of two R p groups.}
R is an independently halogen atom, an alkyl group having 1 to 15 carbon atoms, an aralkyl group having 7 to 34 carbon atoms, an alkoxy group having 1 to 15 carbon atoms, and an alkylthio group having 1 to 15 carbon atoms. It is at least one selected from the group consisting of an alkylamino group having 1 to 15 carbon atoms, a carboxyl group, a carboxylic acid ester group having 1 to 15 carbon atoms in the ester residue, a nitro group and a cyano group.
m is an integer of 1 to 4 independently,
n is an integer of 0 to 3 independently.
The sum of m and n is 4 or less independently for each aniline monomer residue.
k is an integer from 4 to 3000,
Binder for polymer electrolyte fuel cells.

(Item 11)
Item 2. The binder according to Item 10, wherein the number of phosphonic acid residues introduced into the polyaniline is 10% or more with respect to the number of aniline monomer residues.

(Item 12)
A polymer electrolyte fuel cell containing the binder according to item 10 or 11 above.

(Item 13)
The method for producing the catalyst according to any one of the above items 1 to 8.
The following general formula (2):
− (A ² ) _k − (2)
A step of obtaining a phosphorus-containing polyaniline by performing a phosphorification reaction on the polyaniline compound represented by the above, and a step of forming a catalyst from the phosphorus-containing polyaniline are included.
A ² is a substituted or unsubstituted aniline monomer residue,
Each A ² independently has n substituents R.
R, n and k are the same as the definitions in item 1 above.
Method.

(Item 14)
The method for producing the binder according to the above item 10 or 11, wherein the binder is produced.
The following general formula (2):
− (A ² ) _k − (2)
A step of obtaining a phosphorus-containing polyaniline by performing a phosphorification reaction on the polyaniline compound represented by the above, and a step of forming a binder from the phosphorus-containing polyaniline are included.
A ² is a substituted or unsubstituted aniline monomer residue,
Each A ² independently has n substituents R.
R, n and k are the same as the definitions in Section 10 above.
Method.

According to the present invention, by using a catalyst containing polyaniline phosphonic acid, it is possible to provide a positive electrode catalyst having catalytic activity easily at low cost without using a conventional catalyst such as platinum.

According to the present invention, a simple manufacturing method that does not require a step such as recrystallization, for example, a manufacturing method consisting only of a firing step, or a manufacturing method consisting of a step of mixing a metal or bipyridyl solution and firing. A catalyst that can be manufactured is provided.

Further, according to the present invention, by using a binder containing polyaniline phosphonic acid, a halogen-free binder can be obtained. Further, this binder has electrical conductivity in addition to proton conductivity, and it is possible to prevent a phenomenon in which a catalyst that is wrapped in the binder and isolated from the electrode is generated and the catalyst utilization rate is lowered.

FIG. 1 shows the measurement results of the oxygen reduction activity of platinum-supported carbon using PMAP / pyridine as a binder in Example 1 and the measurement results of the oxygen reduction activity of platinum-supported carbon using Nafion as a binder in Comparative Example 1. FIG. 2 shows the measurement results of the oxygen reduction activity of the PMAP fired product (PMAP700, PMAP800, PMAP900) synthesized in Example 2. FIG. 3 shows the measurement results of the oxygen reduction activity of the PMAP / 4,4'-bipyridyl calcined product (PMAP / bpy / DMF / 900) synthesized in Example 3. FIG. 4 shows the measurement results of the oxygen reduction activity of the PANI calcined product (PANI / H _{2 O / 900) synthesized in Comparative Example 2.} Figure 5 is a PMAP / FeCl ₃ sintered body synthesized in Example _{4 (PMAP / FeCl 3/900} ) and PMAP fired body (PMAP / 900) oxygen reduction reaction activity of the measurement results of (oxygen reduction reaction activity evaluation) .. 6, Example 5 PANI-PDE / FeCl ₃ sintered body synthesized in _{(PANI-PDE / FeCl 3/} 900) and PANI-PDE fired body (PANI-PDE / 900) oxygen reduction activity of the measurement results of (oxygen Reduction reaction activity evaluation). 7, PANI-PA / FeCl ₃ sintered body synthesized in Example _{6 (PANI-PA / FeCl 3} /900) and PANI-PA fired body (PANI-PA / 900) oxygen reduction activity of the measurement results of (oxygen Reduction reaction activity evaluation). FIG. 8 shows the results of evaluating the activity of the oxygen reduction reaction of the calcined product of _{the PMAP / FeCl 3} calcined product synthesized in Example 7 that had been acid-immersed and refired.

Hereinafter, the present invention will be described in detail.

[Fuel cell using catalyst and binder containing polyaniline]
The catalyst for a fuel cell of the present invention is obtained by, for example, calcining and carbonizing polyaniline, and exhibits excellent oxygen reduction reaction activity.

As used herein, the term "fuel cell" means a polymer electrolyte fuel cell (PEFC). In order to improve the output of PEFC, in the negative electrode, the three-phase interface of the electrolyte film, the electrode catalyst, and the fuel (negative electrode active material), and in the positive electrode, the electrolyte film, the electrode catalyst, and oxygen (positive electrode active material). It is necessary to widen the area of the phase interface and carry out a chemical reaction efficiently.

In response to such a requirement, the polyaniline used in the present invention contains a phosphorus-containing functional group and has an aniline skeleton, so that the bonding distance due to the functional group is longer than that of graphite used as a conventional electrode catalyst. It is considered that the surface area is increased, the efficiency of oxygen supply is increased, and the catalytic activity can be improved accordingly.

Further, by adding a bipyridine compound to the polyaniline used in the present invention, the following general formula (1h):

It is considered that a network structure in which the compounds represented by are crosslinked with each other is formed, the surface area is further increased, and the efficiency of oxygen supply is increased, thereby exhibiting excellent catalytic activity.

Further, the binder of the present invention can be suitably used as a binder for a fuel cell because the polyaniline used exhibits high proton conductivity and also has conductivity (electrical conductivity). This is in contrast to Nafion, which is currently widely used as a binder for fuel cells, because it is not conductive and can produce electrically isolated catalyst particles, which is an advantage over Nafion. ..

The fuel cell using the catalyst and the binder, which is characterized by being composed of the polyaniline of the present invention, is preferably prepared under the following conditions.

(Polyaniline)
The polyaniline used in the present invention is a compound represented by the following general formula (1).

-(A ¹ ) _k- (1)
Contains polyaniline represented by, where
A ¹ is an independently substituted or unsubstituted aniline monomer residue.
Each A ¹ independently has m phosphonic acid residues R ^p and n substituents R.

The phosphonic acid residue R ^p is represented by the following formula.

In the general formula (1a), R, M ¹ , M ² , m, n, and k are the same as above.

^{M 1} and M ² in the phosphonic acid residue are preferably selected from hydrogen atoms, alkali metals and alkaline earth metals. However, it is preferable that at least one of ^{M 1} and M ^{2 is a hydrogen atom.}

When polyaniline is used as a catalyst, the polyaniline does not necessarily have to have high conductivity, and therefore the presence of hydrogen at the phosphonic acid residue is not always necessary. When polyaniline is used as a binder, it is necessary that the polyaniline has high conductivity, and therefore it is preferable that the polyaniline has a large amount of phosphonic acid residues and has hydrogen.

As used herein, the term "alkali metal" refers to any atom belonging to Group 1 of the Periodic Table. Specific examples of the alkali metal include lithium, sodium, potassium, rubidium, cesium and the like.

As used herein, the term "alkaline earth metal" refers to any atom belonging to Group 2 of the periodic table. Specific examples of alkaline earth metals include beryllium, magnesium, calcium, strontium, barium and radium.

The substituent R is at least one selected from the group consisting of a halogen atom, an alkyl group, an aralkyl group, an alkoxy group, an alkylthio group, an alkylamino group, a carboxyl group, a carboxylic acid alkyl ester group, a nitro group and a cyano group. is there. Of these, electron-donating groups such as alkyl groups, alkoxy groups, alkylthio groups, and alkylamino groups are preferable, and alkyl groups and alkoxy groups are particularly preferable.

Specific examples of the halogen atom include a chlorine atom, a fluorine atom, a bromine atom and an iodine atom, and a chlorine atom and a bromine atom are preferable.

In addition, in this specification, "alkyl" means a monovalent group generated by the loss of one hydrogen atom from a chain or cyclic aliphatic hydrocarbon (alkane). In the case of a chain, it is generally _{represented by C j} H _{2j + 1} − (where j is a positive integer). The chain alkyl can be straight or branched. The cyclic alkyl may be composed of only a cyclic structure, or may have a structure in which a chain alkyl is further bonded to the cyclic structure. The number of carbon atoms in the alkyl can be any natural number. The alkyl has 1 to 30 carbon atoms in one embodiment and 1 to 20 in another embodiment. In yet another embodiment, it is 1-10, and in yet another embodiment, it is 1-5.

In particular, regarding the alkyl group in the substituent R, the number of carbon atoms of the alkyl group is preferably 1 to 15, more preferably 1 to 8, and particularly preferably 1 to 4. Specific examples include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group and pentadecyl group. Can be mentioned.

As used herein, the term "aralkyl group" refers to a structure in which a part of hydrogen atoms of an alkyl group is substituted with an aryl group.

As used herein, the term "aryl group" refers to a group formed by the detachment of one hydrogen atom bonded to the ring of an aromatic hydrocarbon. The number of rings of the aromatic hydrocarbon constituting the aryl group may be one or two or more. It is preferably 1 to 3. When there are a plurality of rings of intramolecular aromatic hydrocarbons, the plurality of rings may or may not be condensed. Specifically, for example, phenyl, naphthyl, anthracenyl, biphenylyl and the like.

In particular, the alkyl group constituting the aralkyl group in R of the general formula (1) may be linear or branched, and preferably has 1 to 10 carbon atoms, and preferably has 1 to 10 carbon atoms. Is more preferably 1 to 5. The aryl group constituting the aralkyl group is preferably an aryl group having 1 to 4 benzene rings which may have a substituent, for example, a phenyl group or a biphenyl group which may have 1 or 2 or more substituents. , Telphenyl (terphenyl) group, naphthyl group, anthryl group, phenanthryl group, pyrenyl group, fluorenyl group and the like, and phenyl group, biphenyl group and naphthyl group are more preferable. Examples of the substituent include an alkyl group having 1 to 3 carbon atoms, a phenyl group, a phenylalkyl group having 7 to 21 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a halogen atom, a formyl group, an acyl group and a carboxyl group. Examples thereof include a cyano group, a nitro group and a sulfone group.

The total number of carbon atoms of the aralkyl group is preferably 7 to 34, and particularly preferably 7 to 15. Specific examples include a benzyl group, a phenylethyl group, a phenylpropyl group, a phenylbutyl group, a phenylpentyl group, a naphthylmethyl group, a naphthylethyl group, a naphthylpropyl group, a naphthylbutyl group, a naphthylpentyl group, an anthrylmethyl group, and an ann. Examples thereof include a thrill ethyl group, an anthrylpropyl group, an anthrylbutyl group, an anthrylpentyl group, a biphenylmethyl group, a biphenylethyl group, a biphenylpropyl group, a biphenylbutyl group and a biphenylpentyl group.

As used herein, the term "alkoxy" refers to a group in which an oxygen atom is bonded to the above alkyl group. That is, when the above alkyl group ^{is represented by RA} −, it means a group represented by ^{RA O −.} The chain alkoxy can be straight or branched. The cyclic alkoxy may be composed of only a cyclic structure, or may have a structure in which a chain alkyl is further bonded to the cyclic structure. The number of carbon atoms in the alkoxy can be any natural number. In one embodiment it is 1-30 and in another embodiment it is 1-20.

Among them, as the alkoxy group in the substituent R, the alkyl group portion may be linear or branched, and the number of carbon atoms is preferably 1 to 15, preferably 1 to 8. It is more preferably present, and particularly preferably 1 to 4. Specific examples include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, nonyloxy group, decyloxy group, undecyloxy group, dodecyloxy group and tridecyl. Examples thereof include an oxy group, a tetradecyloxy group and a pentadecyloxy group.

As used herein, the term "alkylthio" refers to a group in which a sulfur atom is bonded to the above alkyl group. That is, when the above alkyl group ^{is represented by R A} −, it means a group represented by ^{R A S −.} The chain alkylthio can be straight or branched. The cyclic alkylthio may be composed of only a cyclic structure, or may have a structure in which a chain alkyl is further bonded to the cyclic structure. The number of carbon atoms in the alkylthio can be any natural number. In one embodiment it is 1-30 and in another embodiment it is 1-20.

As the alkylthio group in the substituent R, the alkyl group portion may be linear or branched, and the number of carbon atoms is preferably 1 to 15, preferably 1 to 8. Is more preferable, and 1 to 4 is particularly preferable. Specific examples include methylthio group, ethylthio group, propylthio group, butylthio group, pentylthio group, hexylthio group, heptylthio group, octylthio group, nonylthio group, decylthio group, undecylthio group, dodecylthio group, tridecylthio group, tetradecylthio group and penta. Examples include a decylthio group.

As used herein, the term "alkylamino" refers to a group in which an amino group is bonded to the above alkyl group. That is, when the above alkyl group is represented by ^RA −, it refers to a group represented by ^{RA NH −.} The chain alkylamino can be straight or branched. The cyclic alkylamino may be composed of only a cyclic structure, or may have a structure in which a chain alkyl is further bonded to the cyclic structure. The number of carbon atoms in the alkylamino can be any natural number. In one embodiment it is 1-30 and in another embodiment it is 1-20.

As the alkylamino group in the substituent R, the alkyl group portion may be linear or branched, and the number of carbon atoms is preferably 1 to 15, preferably 1 to 8. It is more preferable, and it is particularly preferable that it is 1 to 4. Specific examples include methylamino group, ethylamino group, propylamino group, butylamino group, pentylamino group, hexylamino group, heptylamino group, octylamino group, nonylamino group, decylamino group, undecylamino group and dodecylamino group. Examples include groups, tridecylamino groups, tetradecylamino groups and pentadecylamino groups.

As used herein, the term "carboxylic acid alkyl ester" refers to a group in which a carboxylic acid group is bonded to the above alkyl group. That is, when the above alkyl group ^{is represented by RA} −, it means a group represented by ^{−COOR A.} The chain carboxylic acid alkyl ester can be straight or branched. The cyclic carboxylic acid alkyl ester may be composed of only a cyclic structure, or may have a structure in which a chain alkyl is further bonded to the cyclic structure. The carbon number of the carboxylic acid alkyl ester can be any natural number. In one embodiment it is 1-30 and in another embodiment it is 1-20.

In the carboxylic acid alkyl ester group in the substituent R, the carbon atom of the carboxylic acid is bonded to the benzene ring of the general formula (1). That is, when the benzene ring is described as Ph, it has a structure of ^{Ph-C (= O) -OR A.} As the carboxylic acid alkyl ester group, the number of carbon atoms of the alkyl group is preferably 1 to 15, more preferably 1 to 8, and particularly preferably 1 to 4. Specific examples include methyl carboxylic acid group, ethyl carboxylic acid group, propyl carboxylic acid group, butyl carboxylic acid group, pentyl carboxylic acid group, hexyl carboxylic acid group, heptyl carboxylic acid group, octyl carboxylic acid group, and nonyl carboxylic acid group. Examples thereof include a decyl carboxylate group, an undecyl carboxylate group, a dodecyl carboxylate group, a tridecyl carboxylate group, a tetradecyl carboxylate group and a pentadecyl carboxylate group.

The number m of phosphonic acid residues in the general formula (1) is an integer of 1 to 4, that is, 1, 2, 3 or 4, preferably an integer of 1 to 3, and more preferably 1 to 1. It is an integer of 2. The number n of the substituent R is an integer of 0 to 3, preferably an integer of 0 to 2, and more preferably an integer of 0 to 1. k is an integer of 4 to 3000, preferably an integer of 6 to 2000, and more preferably an integer of 8 to 1200.

In the polyaniline of the general formula (1), adjacent aniline monomer residues are bonded at a para position. That is, when the second aniline monomer residue is bound to the first aniline monomer residue and the third aniline monomer residue is bound to the second aniline monomer residue, the first aniline monomer residue is left. The group and the third aniline monomer residue are in a para-positional relationship on the benzene ring in the second aniline monomer residue.

Specifically, the general formula (1) can be described by, for example, the following general formula (1a).

However, it is known that the skeletal structure of polyaniline is not limited to the structure as described in the general formula (1a). Therefore, the skeletal structure of polyaniline in the present specification is not limited to the basic structure of the general formula (1a).

Specifically, in general, polyaniline is a repeating unit of the phenylenediamine skeleton of the reduced unit of the following general formula (1b) and

It is known to take two types of skeletons, which are repeating units of the quinonediimine skeleton of the oxidized unit of the following general formula (1c).

Therefore, the aniline residue in the polyaniline in the present specification may also have a skeletal structure as represented by the above general formula (1b) or (1c).

The polyaniline in the present specification is the following general formula (1d):

It may have a structure having a repeating unit of.

In the general formula (1d), R is the same as the above definition, M ^1a is the same as the ^{above M 1 , M 2a} is the same as the ^{above M 2 , M 1 b} is the same as the above M 1, and M ^2b is the same as ^{M 2 above.} m ¹ and m ² are the same as m above, and n ¹ and n ² are the same as n above.

In addition, the following four types of polyaniline are described in the international publication WO2014 / 167818.

The polyaniline of the present invention can also have these structures.

In addition, the polyaniline of the present invention may contain other repeating units or components as long as the effects of the present invention are not impaired. For example, the following general formula (1e):

(In the formula, R is the same as the above definition, and M ^1c and M ^2c are independently composed of an alkyl group, an aralkyl group, an aryl group, an alkali metal, an alkaline earth metal, and an ammonium group and a pyridinium group. M ³ is an integer from 0 to 4, n ³ is an integer from 0 to ^{4. However, the sum of m 3} and n ³ is 4 or less.)
It can include a repeating unit represented by.

When the structure of polyaniline is described by a general formula, both ends are generally omitted. Therefore, in the present specification as well, as a general rule, both ends are omitted when describing the structure of polyaniline. .. However, for example, if both end groups are intentionally described in the above general formula (1), the following general formula (1f) is obtained.

E ^1- (A ¹ ) _k- E ² (1f)
Here, E ¹ and E ² are terminal groups, respectively. Usually, one is the polymerization initiation terminal and the other is the polymerization termination terminal.

The terminal structure of polyaniline has not been completely elucidated. If the reaction occurs in which the amine moiety of the aniline monomer binds to the para position of another aniline monomer, as simply expected from the chemical structure of the aniline monomer, then at the aniline monomer residue at one end of the polyaniline It is considered that the hydrogen at the para position remains as it is to form a terminal, and at the aniline monomer residue at the other end, the amino group remains as it is to form a terminal. In this case, if hydrogen at both ends (hydrogen at the para position at one end and hydrogen at the amino group at the other end) is intentionally described in the above formula (1), it is represented by the following general formula (1 g).

[H- (A ¹ ) _k- H] (1 g)
On the other hand, for example, WO2014 / 167818 explains that an aniline oligomer having a phenazine ring structure is produced in the initial stage of polymerization of aniline, and the oligomer residue becomes the polymerization initiation side end of the polymer. However, even when a structure different from the structure of the monomer residue in the repeating unit exists at the terminal in this way, the type of the terminal group of the polyaniline has a small effect on the performance of the polyaniline, so the structure of the terminal group is ignored. be able to.

Monomer residues in the polyaniline ( "A ^1" in the above general formula (1), the general formula (2) in the "A ^2"), all may be the same or may be a plurality of types. That is, it may be a homopolymer or a copolymer. It is preferably a copolymer. Further, the copolymer may be a block copolymer or a random copolymer. In a random copolymer, multiple types of monomer residues are arranged in a disorderly manner. As described in the above-mentioned International Publication WO2014 / 167818, polyaniline obtained by oxidatively polymerizing an aniline monomer is known to have a structure having a certain regular repeating unit. It is considered that polyaniline having such regularity can be produced also in the production method of the present invention, and the polyaniline having such regularity is used as the polymer intended for the production method of the present invention. Can be done.

Polyaniline is a group consisting of at least a phosphonic acid group (-PO ₃ H ₂ ) or a phosphonate monohydrogen base (-PO ₃ HM ⁸ , where M ⁸ is an alkali metal, an alkaline earth metal, an ammonium group, and a pyridinium group. A phosphonate group or a phosphonate monohydrogen base can be doped against the nitrogen of the polyaniline main chain by its hydrogen atom if it contains a monomer residue having (selected from).

In addition, in this specification, a phosphonate monohydrogen base means a group having a structure of a phosphonate monohydrogen salt. That is, of the two hydrogens of the phosphonic acid group, only one hydrogen is substituted with a metal atom or the like to form a salt, and the other hydrogen remains as it is.

The polyaniline used in the present invention is preferably a conductive polyaniline having self-doping property.

In the polyaniline used in the present invention, the amount of the phosphonic acid residue introduced into the polyaniline compound can be appropriately designed. That is, a desired amount can be introduced in consideration of the physical characteristics required for the catalyst or the binder. Assuming that the number of aniline monomer residues present in polyaniline is 100%, for example, the introduction rate is 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80. It can be adjusted to be% or more, 90% or more, or 95% or more. When it is preferable to suppress the introduction rate to a low level, for example, the introduction rate can be adjusted to be 95% or less, 90% or less, 85% or less, 75% or less, or 70% or less. Is.

By increasing the amount of the phosphonic acid residue introduced into the polyaniline compound, the effect of introducing the phosphonic acid residue can be enhanced. For example, the effect of imparting conductivity can be enhanced. As a means for adjusting the amount of the phosphonic acid residue introduced into the polyaniline compound, it is preferable to adjust the composition of the reaction raw material when synthesizing the polyaniline, for example, the amount of phosphite, the amount of the phospholating agent, and the like. Further, the amount of the phosphonic acid residue introduced into the polyaniline compound may be adjusted by adjusting the reaction conditions, for example, the reaction temperature and the reaction time.

The polyaniline used in the present invention may be produced by a conventionally known method. For example, it can be produced by the method described in International Publication WO2014 / 167818.

Further, the polyaniline used in the present invention may be produced by a method different from the conventionally known method.

[New production method of phosphorus-containing polyaniline]
In the production method of the present invention, a polyaniline compound or a polyaniline mixture containing a polyaniline compound is phosphonized to produce a phosphorus-containing polyaniline.

(Polyaniline compound)
As used herein, the term "polyaniline compound" as used in a novel method for producing a phosphorus-containing polyaniline means a polyaniline capable of undergoing a phosphorification reaction to obtain a phosphorus-containing polyaniline. Specifically, it is an unsubstituted polyaniline or a substituted polyaniline. Substituent polyaniline refers to a polyaniline having a substituent at least one of its benzene ring and nitrogen of an amino group residue. In the benzene ring, the nitrogen of the amino group residue is at the 1-position, and substituents are present at 1 to 4 of the 2-position, 3-position, 5-position and 6-position (that is, the ortho-position or the meta-position). be able to.

As used herein, the term "polyaniline mixture" refers to a mixture of two or more types of polyaniline compounds.

Polyaniline is obtained by polymerizing an aniline monomer compound or a mixture of aniline monomers. As the polymerization method, any conventionally known method as a polymerization method for obtaining polyaniline from an aniline monomer can be adopted.

As used herein, the term "aniline monomer" or "aniline monomer compound" means a monomer capable of carrying out a polymerization reaction for obtaining polyaniline from aniline. Specifically, it is an unsubstituted aniline (C ₆ H ₅ NH ₂ ) or a substituted aniline or a salt thereof. Substituent aniline refers to one having a substituent at at least one of its benzene ring and amino group. In the benzene ring, the amino group is at the 1-position, and substituents can be present at 1 to 4 of the 2-position, 3-position, 5-position and 6-position (that is, the ortho-position or the meta-position). However, since substituted aniline having a substituent at the 4-position (para-position) cannot be polymerized, the 4-position (para-position) substituted aniline is not included in the aniline monomer. A salt of an unsubstituted or substituted aniline is a salt in which the amino group portion is a salt, and the salt portion does not interfere with the polymerization reaction. Examples of salts of unsubstituted or substituted aniline include ammonium salts.

As used herein, the term "aniline monomer mixture" refers to a mixture of two or more types of aniline monomer compounds.

The polyaniline compound used as a raw material in the production method of the present invention has one aniline monomer residue at the 1st position (nitrogen) and another aniline monomer residue at the 4th position, with the nitrogen of the amino group residue as the 1st position. Has a combined structure. Therefore, the obtained phosphorus-containing polyaniline (conductive polyaniline and phosphorus-containing polyaniline ester) also has a structure in which the 1-position (nitrogen) of one aniline monomer residue and the 4-position of another aniline monomer residue are bonded. The resulting phosphorus-containing polyaniline (conductive polyaniline and phosphorus-containing polyaniline ester) is at the 2-position, 3-position, 5-position and 6-position (that is, the ortho-position or meta-position) with the nitrogen of the amino group residue as the 1-position. The structure is such that substituents can be present in one to four of them.

As used herein, the term "phosphopolyaniline-containing" refers to polyaniline having a phosphonic acid residue.

As used herein, the term "phosphopolyaniline-containing ester" refers to a phosphopolyaniline-containing ester having a phosphonic acid residue that is an alkyl ester or an aralkyl ester.

As used herein, the term "residue" refers to a group that remains after the reaction material has reacted. The amino group residue refers to a portion remaining in the polymer produced by desorbing hydrogen from the amino group of aniline when aniline is polymerized. Further, for example, the unsubstituted aniline monomer residue is a portion remaining in the polymer produced by one unsubstituted aniline monomer molecule when aniline is polymerized, that is, from one benzene ring, one nitrogen atom and hydrogen. Refers to the part that becomes. The substituted aniline monomer residue is a portion remaining in the polymer produced by one substituted aniline monomer molecule when aniline is polymerized, that is, one benzene ring and one nitrogen atom as a skeleton, and further hydrogen or a substituent. Refers to the part containing. In addition, in this specification, an aniline monomer residue is also referred to as an aniline unit.

In the method for producing phosphorus-containing polyaniline of the present invention, a polyaniline compound represented by the following general formula (2) is used as a raw material polymer for phosphorification.

− (A ² ) _k − (2)
Here, A ² is a substituted or unsubstituted aniline residue, and each A ² has n substituents R.

R is at least one selected from the group consisting of a halogen atom, an alkyl group, an aralkyl group, an alkoxy group, an alkylthio group, an alkylamino group, a carboxyl group, a carboxylic acid alkyl ester group, a nitro group and a cyano group. Of these, electron-donating groups such as halogen atoms, alkyl groups, alkoxy groups, alkylthio groups, and alkylamino groups are preferable, and alkyl groups and alkoxy groups are particularly preferable.

Specific examples of the halogen atom include a chlorine atom, a fluorine atom, a bromine atom and an iodine atom, and a chlorine atom and a bromine atom are preferable.

In addition, in this specification, "alkyl" means a monovalent group generated by the loss of one hydrogen atom from a chain or cyclic aliphatic hydrocarbon (alkane). In the case of a chain, it is generally _{represented by C j} H _{2j + 1} − (where j is a positive integer). The chain alkyl can be straight or branched. The cyclic alkyl may be composed of only a cyclic structure, or may have a structure in which a chain alkyl is further bonded to the cyclic structure. The number of carbon atoms in the alkyl can be any natural number. The alkyl has 1 to 30 carbon atoms in one embodiment and 1 to 20 in another embodiment. In yet another embodiment, it is 1-10, and in yet another embodiment, it is 1-5.

In particular, regarding the alkyl group in R, the number of carbon atoms of the alkyl group is preferably 1 to 15, more preferably 1 to 8, and particularly preferably 1 to 4. Specific examples include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group and pentadecyl group. Can be mentioned.

As used herein, the term "aralkyl group" refers to a structure in which a part of hydrogen atoms of an alkyl group is substituted with an aryl group.

As used herein, the term "aryl group" refers to a group formed by the detachment of one hydrogen atom bonded to the ring of an aromatic hydrocarbon. The number of rings of the aromatic hydrocarbon constituting the aryl group may be one or two or more. It is preferably 1 to 3. When there are a plurality of rings of intramolecular aromatic hydrocarbons, the plurality of rings may or may not be condensed. Specifically, for example, phenyl, naphthyl, anthracenyl, biphenylyl and the like. The aryl group preferably has 6 to 30 carbon atoms, more preferably 6 to 14 carbon atoms, and even more preferably 6 to 10 carbon atoms.

In particular, the alkyl group constituting the aralkyl group in the substituent R of the general formula (2) may be linear or branched, and preferably has 1 to 10 carbon atoms. It is more preferable that the number of carbon atoms is 1 to 5. The aryl group constituting the aralkyl group is preferably an aryl group having 1 to 4 benzene rings which may have a substituent, for example, a phenyl group or a biphenyl group which may have 1 or 2 or more substituents. , Telphenyl (terphenyl) group, naphthyl group, anthryl group, phenanthryl group, pyrenyl group, fluorenyl group and the like, and phenyl group, biphenyl group and naphthyl group are more preferable. Examples of the substituent include an alkyl group having 1 to 3 carbon atoms, a phenyl group, a phenylalkyl group having 7 to 21 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a halogen atom, a formyl group, an acyl group and a carboxyl group. Examples thereof include a cyano group, a nitro group and a sulfone group.

The total number of carbon atoms of the aralkyl group is preferably 7 to 34, and particularly preferably 7 to 15. Specific examples include a benzyl group, a phenylethyl group, a phenylpropyl group, a phenylbutyl group, a phenylpentyl group, a naphthylmethyl group, a naphthylethyl group, a naphthylpropyl group, a naphthylbutyl group, a naphthylpentyl group, an anthrylmethyl group, and an ann. Examples thereof include a thrill ethyl group, an anthrylpropyl group, an anthrylbutyl group, an anthrylpentyl group, a biphenylmethyl group, a biphenylethyl group, a biphenylpropyl group, a biphenylbutyl group and a biphenylpentyl group.

As used herein, the term "alkoxy" refers to a group in which an oxygen atom is bonded to the above alkyl group. That is, when the above alkyl group ^{is represented by RA} −, it means a group represented by ^{RA O −.} The chain alkoxy can be straight or branched. The cyclic alkoxy may be composed of only a cyclic structure, or may have a structure in which a chain alkyl is further bonded to the cyclic structure. The number of carbon atoms in the alkoxy can be any natural number. In one embodiment it is 1-30 and in another embodiment it is 1-20.

Among them, as the alkoxy group in the substituent R of the above general formula (2), the alkyl group portion may be linear or branched, and the number of carbon atoms is 1 to 15. It is preferably 1 to 8, more preferably 1 to 4, and particularly preferably 1 to 4. Specific examples include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, nonyloxy group, decyloxy group, undecyloxy group, dodecyloxy group and tridecyl. Examples thereof include an oxy group, a tetradecyloxy group and a pentadecyloxy group.

As used herein, the term "alkylthio" refers to a group in which a sulfur atom is bonded to the above alkyl group. That is, when the above alkyl group ^{is represented by R A} −, it means a group represented by ^{R A S −.} The chain alkylthio can be straight or branched. The cyclic alkylthio may be composed of only a cyclic structure, or may have a structure in which a chain alkyl is further bonded to the cyclic structure. The number of carbon atoms in the alkylthio can be any natural number. In one embodiment it is 1-30 and in another embodiment it is 1-20.

As the alkylthio group in the substituent R of the general formula (2), the alkyl group portion may be linear or branched, and the number of carbon atoms is preferably 1 to 15. It is more preferably 1 to 8, and particularly preferably 1 to 4. Specific examples include methylthio group, ethylthio group, propylthio group, butylthio group, pentylthio group, hexylthio group, heptylthio group, octylthio group, nonylthio group, decylthio group, undecylthio group, dodecylthio group, tridecylthio group, tetradecylthio group and penta. Examples include a decylthio group.

As used herein, the term "alkylamino" refers to a group in which an amino group is bonded to the above alkyl group. That is, when the above alkyl group is represented by ^RA −, it refers to a group represented by ^{RA NH −.} The chain alkylamino can be straight or branched. The cyclic alkylamino may be composed of only a cyclic structure, or may have a structure in which a chain alkyl is further bonded to the cyclic structure. The number of carbon atoms in the alkylamino can be any natural number. In one embodiment it is 1-30 and in another embodiment it is 1-20.

As the alkylamino group in the substituent R of the general formula (2), the alkyl group portion may be linear or branched, and the number of carbon atoms is preferably 1 to 15. , 1 to 8, and particularly preferably 1 to 4. Specific examples include methylamino group, ethylamino group, propylamino group, butylamino group, pentylamino group, hexylamino group, heptylamino group, octylamino group, nonylamino group, decylamino group, undecylamino group and dodecylamino group. Examples include groups, tridecylamino groups, tetradecylamino groups and pentadecylamino groups.

As used herein, the term "carboxylic acid alkyl ester" refers to a group in which a carboxylic acid group is bonded to the above alkyl group. That is, when the above alkyl group ^{is represented by RA} −, it means a group represented by ^{−COOR A.} The chain carboxylic acid alkyl ester can be straight or branched. The cyclic carboxylic acid alkyl ester may be composed of only a cyclic structure, or may have a structure in which a chain alkyl is further bonded to the cyclic structure. The carbon number of the carboxylic acid alkyl ester can be any natural number. In one embodiment it is 1-30 and in another embodiment it is 1-20.

In the carboxylic acid alkyl ester group in the substituent R of the general formula (2), the carbon atom of the carboxylic acid is bonded to the benzene ring of the general formula (2). That is, when the benzene ring is described as Ph, it has a structure of ^{Ph-C (= O) -OR A.} As the carboxylic acid alkyl ester group, the number of carbon atoms of the alkyl group is preferably 1 to 15, more preferably 1 to 8, and particularly preferably 1 to 4. Specific examples include methyl carboxylic acid group, ethyl carboxylic acid group, propyl carboxylic acid group, butyl carboxylic acid group, pentyl carboxylic acid group, hexyl carboxylic acid group, heptyl carboxylic acid group, octyl carboxylic acid group, and nonyl carboxylic acid group. Examples thereof include a decyl carboxylate group, an undecyl carboxylate group, a dodecyl carboxylate group, a tridecyl carboxylate group, a tetradecyl carboxylate group and a pentadecyl carboxylate group.

In the above general formula (2), n is an integer of 0 to 4 (that is, 0, 1, 2, 3 or 4), preferably an integer of 0 to 2, and more preferably an integer of 0 to 1. is there. k is an integer of 4 to 3000, preferably an integer of 6 to 2000, and more preferably an integer of 8 to 1200.

As used herein, the term "alkali metal" refers to any atom belonging to Group 1 of the Periodic Table. Specific examples of the alkali metal include lithium, sodium, potassium, rubidium, cesium and the like.

As used herein, the term "alkaline earth metal" refers to any atom belonging to Group 2 of the periodic table. Specific examples of alkaline earth metals include beryllium, magnesium, calcium, strontium, barium and radium.

In one embodiment, the substituent R in the polyaniline compound in the general formula (2) is a halogen. If halogen is present in the substituent of polyaniline, the Hirao reaction described later can be carried out. When polyaniline having a halogen as a substituent R is used, the number of aniline monomer residues in which halogen is present as a substituent can be arbitrarily selected. The ratio of aniline monomer residues in which halogen is present as a substituent is, for example, 10% or more, 20% or more, 30% or more, 40% or more, 50, assuming that the number of aniline monomer residues present in polyaniline is 100%. It is possible to select from% or more, 60% or more, 70% or more, 80% or more, 90% or more, or 95% or more. Alternatively, it may be 100%. Further, if it is desired to control the halogen content for some reason, it can be designed so that the number of aniline monomer residues in which the halogen is present is suppressed. In such a case, for example, the ratio can be designed to be 95% or less, 90% or less, 85% or less, or 80% or less.

(Other polymers)
In the method for producing a phosphorus-containing polyaniline of the present invention, it is preferable to use the above-mentioned substituted or unsubstituted polyaniline compound as a polymer at the time of phosphorification. However, if necessary, in the polymer mixture used as a raw material in the production of phosphorus-containing polyaniline, a phosphorizable polymer other than the above-mentioned substituted or unsubstituted polyaniline compound (hereinafter, "other type polymer") is used in the present invention. It may be contained in a small amount so as not to interfere with the effect of. That is, a substituted or unsubstituted polyaniline compound having no phosphonic acid may be copolymerized, if necessary. For example, a small amount of a substituted or unsubstituted polyaniline compound having no acidic substituent may be used, or a small amount of a substituted or unsubstituted polyaniline compound having an acidic substituent (for example, sulfonic acid) other than phosphonic acid may be used. It may be used, or a small amount of a substituted or unsubstituted polyaniline compound in which the phosphonic acid group is indirectly bonded without being directly bonded to the benzene ring may be used.

However, if the amount of the other type polymer used is too large, the advantages of the present invention will be impaired. Therefore, it is preferable that the amount of the other type polymer used is not too large. The amount of the other type polymer used is preferably 40 mol% or less, more preferably 30 mol% or less, and 20 mol% or less of the total amount of the substituted or unsubstituted polyaniline compound used for the polymerization. It is more preferably 10 mol% or less, particularly preferably 5 mol% or less, particularly preferably 3 mol% or less, and most preferably 1 mol% or less.

[Phosphonation reaction]
Phosphonation of a polyaniline compound or a mixture of polyaniline with phosphite gives a phosphorus-containing polyaniline. As the phosphonization method, any phosphonization method capable of introducing a phosphonic acid residue into the polyaniline compound can be adopted. As the phosphite, any phosphite capable of reacting with a polyaniline compound or a polyaniline mixture can be used.

Preferably, the polyaniline compound or the polyaniline mixture is oxidized with an oxidizing agent and reacted with a phosphite compound represented by the following general formula (3) or general formula (4) (preferably trialkylphosphite or dialkylphosphite). A method of synthesizing phosphorus-containing polyaniline can be adopted.

General formula (3):

(Here, M ^{3 to} M ⁵ may be the same or different, and independently have an alkyl group having 1 to 15 carbon atoms, an aralkyl group having 7 to 34 carbon atoms, and 6 to 6 carbon atoms. It is selected from the group consisting of 30 aryl groups, hydrogen atoms, alkali metals, alkaline earth metals, ammonium groups, and pyridinium groups, provided that one of M ^{3 to} M ⁵ is an alkaline earth metal. the two O ^- a do not one of the remaining two of said alkaline earth metal atom is bonded M ³ ~M ⁵ present structure).
General formula (4):

(Here, M ⁶ and M ⁷ may be the same, and independently, an alkyl group having 1 to 15 carbon atoms, an aralkyl group having 7 to 34 carbon atoms, and an aryl group having 6 to 30 carbon atoms, respectively. It is selected from the group consisting of a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, and a pyridinium group. However, when one of M ⁶ and M ⁷ is an alkaline earth metal, two O's are used. ^The structure is such that the alkaline earth metal atom is bonded to ^{− and the other of M 6} and M ⁷ does not exist.)
In the general formula (3), ^{a compound in which only one of M 3 to} M ⁵ is a hydrogen atom has a tautomer relationship with the general formula (4) and becomes the same compound. In the present specification, the compound will be described as a compound of the general formula (4).

As used herein, the term "phosphonization" means a reaction in which a polyaniline compound or a mixture of polyanilines is reacted with phosphite to synthesize phosphorus-containing polyaniline. As used herein, the term "phosphonating agent" means an oxidizing agent or a catalyst used for a Hirao reaction or the like. As used herein, "oxidation" means the extraction of hydrogen atoms from a polyaniline compound or polyaniline mixture using an oxidizing agent. As used herein, the term "oxidizing agent" refers to a reagent that causes such an oxidizing reaction.

Therefore, when an oxidizing agent is used, hydrogen atoms are lost from the polyaniline compound. Then, the dehydrogenated polyaniline compound reacts with the phosphite compound of the general formula (3) (for example, trialkylphosphite).

(Other phospholation reactions)
In the phosphorification reaction of the present invention, the above-mentioned "nucleophilic" that synthesizes phosphopolyaniline-containing polyaniline by reaction with phosphite represented by the general formula (3) by oxidation with a polyaniline compound or a polyaniline mixture using an oxidizing agent. It is preferable to use a "phosphorization reaction by addition". However, if necessary, a method called phosphonation by the Hirao reaction may be adopted.

In the present specification, "phosphorization by Hirao reaction" means a reaction for synthesizing phosphopolyaniline-containing polyaniline by coupling a polyaniline compound or a polyaniline mixture with a dialkylphosphite represented by the general formula (4). In the present specification, the "Hirao reaction" refers to a reaction in which phosphite is bound to a benzene ring in the presence of a catalyst such as a palladium compound.

As the catalyst for the Hirao reaction, any known catalyst can be used, preferably a palladium compound, and more preferably Pd (PPh ₃ ) ₄ or Pd (OAc) ₂ . Further, if necessary, in order to prevent catalyst deactivation in phosphonization by the Hirao reaction, it is preferable to vacuum-heat the reaction vessel (hereinafter referred to as frame dry) before charging the reaction. The Hirao reaction is specifically described in the international publication WO2014 / 167818 and the like.

(Amount of phosphite)
The amount of phosphite used in the method of the present invention is not particularly limited. It can be appropriately designed in consideration of the type of the polyaniline compound, the type of phosphite to be introduced into the polyaniline compound, and the like. For example, if the polyaniline compound is an unsubstituted aniline, phosphonic acid residues can be introduced at four positions on the benzene ring, so that the number of phosphonic acid residues that can be introduced is four times the number of aniline monomer residues. The amount of phosphite can be appropriately determined according to the number of phosphonic acid residues to be introduced. If a large number of phosphonic acid residues are to be introduced, a large amount of phosphite may be used, and if a small number of phosphonic acid residues are to be introduced, a small amount of phosphite may be used.

For example, in one embodiment, phosphite is used in an amount of 0.05 equivalents or more and 10 equivalents or less with respect to the polyaniline compound represented by the general formula (2). If necessary, for example, the amount of phosphite may be 0.1 equivalent or more, 0.3 equivalent or more, 0.5 equivalent or more, 1 equivalent or more, or 2 equivalent or more. Further, for example, the amount of phosphite may be 9 equivalents or less, 8 equivalents or less, 7 equivalents or less, 6 equivalents or less, or 5 equivalents or less.

Here, the equivalent of phosphite to the polyaniline compound is a calculated value of the total number of places where phosphonic acid residues existing in the polyaniline compound can be introduced (for example, in the case of unsubstituted polyaniline, the number of aniline monomer residues). It is calculated as the number of moles of phosphite relative to (4 times).

(Amount of phosphonating agent)
The amount of the phosphonating agent used in the method of the present invention is not particularly limited. It can be appropriately designed in consideration of the type of the polyaniline compound, the type and amount of the phosphonic acid residue to be introduced into the polyaniline compound, and the like. For example, if the polyaniline compound is an unsubstituted aniline, phosphonic acid residues can be introduced at four positions on the benzene ring, so that the number of phosphonic acid residues that can be introduced is four times the number of aniline monomer residues. The amount of the phosphonating agent can be appropriately determined according to the number of phosphonic acid residues to be introduced. When introducing a large number of phosphonic acid residues, a large amount of phosphonating agent may be used, and when introducing a small number of phosphonic acid residues, a small amount of phosphonating agent may be used. ..

For example, in one embodiment, the phosphonating agent is used in an amount of 0.05 equivalents or more and 10 equivalents or less with respect to the polyaniline compound represented by the general formula (2). If necessary, for example, the amount of the phospholating agent may be 0.1 equivalent or more, 0.3 equivalent or more, 0.5 equivalent or more, 1 equivalent or more, or 2 equivalent or more. Further, for example, the amount of the phospholating agent may be 9 equivalents or less, 8 equivalents or less, 7 equivalents or less, 6 equivalents or less, or 5 equivalents or less.

Here, the equivalent of the phosphonating agent to the polyaniline compound is a calculated value of the total number of places where phosphonic acid residues existing in the polyaniline compound can be introduced (for example, in the case of unsubstituted polyaniline, the number of aniline monomer residues). Is calculated as the number of moles of the phospholating agent relative to (4 times).

(Phosphonation rate)
In the method of the present invention, the amount of the phosphonic acid residue introduced into the polyaniline compound can be appropriately designed. That is, a desired amount can be introduced in consideration of the physical characteristics required for the target phosphorus-containing polyaniline. Assuming that the number of aniline monomer residues present in phosphorus-containing polyaniline is 100%, for example, the introduction rate is 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more. , 80% or more, 90% or more, or 95% or more can be adjusted. Alternatively, it may be 100%. If high conductivity is desired, it can be designed to introduce more phosphonic acid residues. It can also be designed to suppress the number of phosphonic acid residues introduced if, for some reason, it is desired to control the phosphonization rate. In such a case, for example, the introduction rate can be adjusted to be 95% or less, 90% or less, 85% or less, or 80% or less.

By increasing the amount of the phosphonic acid residue introduced into the polyaniline compound, the effect of introducing the phosphonic acid residue can be enhanced. For example, the effect of imparting conductivity can be enhanced. As a means for adjusting the amount of the phosphonic acid residue introduced into the polyaniline compound, it is preferable to adjust the amount of the above-mentioned phosphite or the amount of the phosphonating agent. Further, the amount of the phosphonic acid residue introduced into the polyaniline compound may be adjusted by adjusting the reaction conditions, for example, the reaction temperature and the reaction time.

(Oxidant)
When an oxidizing agent is used in the phosphorification reaction in the present invention, hydrogen atoms are removed from the polyaniline compound. That is, the polyaniline compound whose oxidation state is an emeraldine base is converted into a pernigraniline salt or a base. Therefore, the phospholation reaction is carried out in the presence of an oxidizing agent to cause this dehydrogenation. As the oxidizing agent, an oxidizing agent generally used in phosphonization can be used. Specific examples include ammonium peroxodisulfate, sodium peroxodisulfate, hydrogen peroxide, ferric chloride, and the like, and ammonium peroxodisulfate is preferably used.

The amount of the oxidizing agent used is not limited as long as the amount of oxidation can proceed. It is preferably 0.5 equivalents or more, more preferably 0.7 equivalents or more, further preferably 1.0 equivalents or more, and 1.5 equivalents, based on the total amount of the polyaniline compound to be phospholated. The above is the most preferable. Then, if necessary, it may be 2.1 equivalents or more, 2.2 equivalents or more, 2.4 equivalents or more, 2.6 equivalents or more, 2.8 equivalents or more, or 3.0 equivalents or more. Further, the amount of the polyaniline compound to be phospholated is preferably 10 equivalents or less, more preferably 8 equivalents or less, further preferably 6 equivalents or less, and particularly preferably 5 equivalents or less. Most preferably, it is 4 equivalents or less. Then, if necessary, 3.9 equivalents or less, 3.7 equivalents or less, 3.6 equivalents or less, 3.5 equivalents or less, 3.4 equivalents or less, 3.3 equivalents or less, 3.2 equivalents or less, or It is also possible to make it 3.1 equivalents or less.

Here, the equivalent of the oxidizing agent to the polyaniline compound is a calculated value of the total number of places where phosphonic acid residues existing in the polyaniline compound can be introduced (for example, in the case of unsubstituted polyaniline, the number of aniline monomer residues). It is calculated as the number of moles of oxidant relative to (4 times). For example, if 1 mol of a compound such as persulfate is an oxidizing agent capable of extracting 2 mol of hydrogen, 0.5 mol of the oxidizing agent is 1 equivalent.

(base)
Phosphonation by the Hirao reaction of the present invention may be carried out using a base.

Examples of the base include triethylamine, sodium carbonate, potassium carbonate, cesium carbonate, potassium phosphate, propylene oxide and the like, and triethylamine and cesium carbonate are particularly preferable.

(solvent)
The phospholation reaction of the present invention may be carried out using a solvent, if necessary. Preferred solvents include water, aqueous ammonia, hydrochloric acid, methanol, ethanol, isopropanol, acetonitrile, dimethylformamide, acetone, 2-butanone, dimethylacetamide, dimethyl sulfoxide, tetrahydrofuran, dioxane, toluene, N-methyl-2-pyrrolidone (hereinafter, NMP) and the like. Water and NMP are particularly preferred.

(Reaction temperature)
In the method of the present invention, the reaction temperature for phosphonation is not particularly limited. It is preferably 20 ° C. or higher, more preferably 30 ° C. or higher, and even more preferably 40 ° C. or higher. Further, it is preferably 200 ° C. or lower, more preferably 160 ° C. or lower, still more preferably 130 ° C. or lower, and even more preferably 120 ° C. or lower. If the reaction temperature is within a preferable range, a phosphorus-containing polyaniline ester can be obtained in a high yield.

(Reaction time)
In the method of the present invention, the reaction time for phosphonation is not particularly limited. In each condition, a sufficient time for reaction may be appropriately selected. If the reaction is sufficiently advanced, the difference in reaction time does not significantly affect the effect of the present application.

The reaction time is preferably 1 hour or longer, more preferably 3 hours or longer, still more preferably 6 hours or longer, even more preferably 9 hours or longer, and particularly preferably 12 hours or longer. Yes, it can be 15 hours or more, 18 hours or more, 21 hours or more, or 24 hours or more, if necessary. Further, it is preferably 7 days or less, more preferably 5 days or less, further preferably 3 days or less, still more preferably 2 days or less, and particularly preferably 36 hours or less. If necessary, it can be 30 hours or less, 28 hours or less, or 26 hours or less.

[Hydrolysis]
When the phosphorus-containing polyaniline obtained by phosphorification in the method of the present invention is an ester, that is, when the phosphonic acid residue introduced into the polyaniline compound is an ester, the ester is hydrolyzed as necessary. Can be carried out. By performing hydrolysis, for example, polyaniline having proton conductivity and conductivity can be obtained.

As the method of hydrolysis, any method known as a method of hydrolyzing a phosphonate ester can be adopted. For example, hydrolysis can be carried out by a method such as treatment with a strong acid or treatment with a strong alkali. Examples of the strong acid include protonic acids such as hydrochloric acid and sulfuric acid, and Lewis acids such as trimethylsilyl bromide. Examples of the strong alkali include sodium hydroxide and the like. Here, when Lewis acid is used, for example, a method of reacting with Lewis acid and then reacting with water can be preferably used.

The reaction conditions such as the reaction temperature and reaction time of hydrolysis may be adjusted so that the hydrolysis proceeds to a desired degree, and are not particularly limited. For example, higher reaction temperatures, longer reaction times, etc. can be employed if it is desired to hydrolyze all esters to achieve high proton conductivity and conductivity.

For example, the reaction temperature during hydrolysis is 20 ° C. or higher, more preferably 30 ° C. or higher, and even more preferably 40 ° C. or higher. Further, it is preferably 200 ° C. or lower, more preferably 160 ° C. or lower, still more preferably 130 ° C. or lower, and even more preferably 120 ° C. or lower. If the reaction temperature is within a preferable range, a phosphorus-containing polyaniline ester can be obtained in a high yield.

Further, for example, the reaction time of hydrolysis is preferably 1 hour or more, more preferably 2 hours or more, and further preferably 3 hours or more. Further, it is preferably 2 days or less, more preferably 1 day or less, further preferably 12 hours or less, and even more preferably 6 hours or less.

[Phosphorus-containing polyaniline]
The phosphorus-containing polyaniline of the present invention is produced by the above method.

As used herein, "phosphory-containing polyaniline" refers to one obtained by phosphonating a polyaniline compound. The phosphorus-containing polyaniline of the present invention may be a phosphorus-containing polyaniline having no ester bond at the phosphonic acid residue portion, or may be a phosphorus-containing polyaniline ester having an ester bond at the phosphonic acid residue portion. A polyaniline compound in which a phosphonate ester is bonded as a substituent is referred to as a polyaniline ester in the present specification. Phosphorus-containing polyaniline esters are particularly useful as intermediates for the production of conductive polyanilines.

The degree of polymerization of polyaniline can be arbitrarily set, for example, 4 or more, 6 or more, or 8 or more, and 3,000 or less, 2,000 or less, or 1,200 or less. It is possible to Alternatively, the degree of polymerization described for k in the following general formula (1) can be used.

Similarly, the molecular weight of polyaniline can be set arbitrarily. For example, the molecular weight can be set to correspond to the degree of polymerization described for k in the following general formula (1).

The number average molecular weight of polyaniline can be, for example, 400 or more, 600 or more, or 800 or more, and can be 600,000 or less, 400,000 or less, or 240,000 or less. is there.

The weight average molecular weight of polyaniline can be, for example, 800 or more, 1,200 or more, or 1,600 or more, and 1,200,000 or less, 800,000 or less, or 480,000 or less. It is possible to

According to the method for producing a phosphorus-containing polyaniline of the present invention, it is possible to easily obtain a phosphorus-containing polyaniline having a high degree of polymerization. In addition, a phosphorus-containing polyaniline ester having a high degree of polymerization can be easily obtained. More specifically, for example, by using a polyaniline compound having a high degree of polymerization as a raw material for carrying out a phospholation reaction, a phosphorus-containing polyaniline having a high degree of polymerization can be easily obtained.

The phosphorus-containing polyaniline obtained by the above novel production method is represented by, for example, the general formula (1):
-(A ¹ ) _k- (1)
Here, A ¹ is an aniline monomer residue independently. k is the degree of polymerization and is any positive integer. Specifically, for example, it can be 4 or more, 10 or more, 100 or more, 500 or more, 1000 or more or 2000 or more, and for example, 10,000 or less, 5,000 or less, 4,000 or less or. It can be 3,000 or less. The molecular weight of the polyaniline of the general formula (1) is an amount corresponding to the degree of polymerization. Regarding the number average molecular weight and the weight average molecular weight, the above-mentioned description regarding the polyaniline in the present specification also applies to the polyaniline of the general formula (1).

Adjacent aniline monomer residues are attached at the para position. That is, when the second aniline monomer residue is bound to the first aniline monomer residue and the third aniline monomer residue is bound to the second aniline monomer residue, the first aniline monomer residue is left. The group and the third aniline monomer residue are in a para-positional relationship on the benzene ring in the second aniline monomer residue.

Further, as for the further details of the general formula (1) of the phosphorus-containing polyaniline obtained by the new production method, the description of the general formula (1) regarding the catalyst of the present invention is directly applicable.

In one embodiment of the invention, the phosphorus-containing polyaniline is a self-doping conductive polyaniline.

For self-doping conductive polyaniline, the presence of hydrogen at the phosphonic acid residue is required. The number of phosphon residues in which hydrogen is present in the phosphorus-containing polyaniline can be arbitrarily selected. The ratio of phosphone residues in which hydrogen is present is, for example, 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, assuming that the number of aniline monomer residues present in phosphorus-containing polyaniline is 100%. , 60% or more, 70% or more, 80% or more, 90% or more, or 95% or more can be selected. Alternatively, it may be 100%. It can also be designed to suppress the number of phosphonic acid residues in which hydrogen is present, if for some reason it is desired to control the hydrogen content. In such a case, assuming that the number of aniline monomer residues present in the phosphorus-containing polyaniline is 100%, for example, the ratio is 95% or less, 90% or less, 85% or less, 80% or less, 75% or less, Alternatively, it can be designed to be 70% or less.

In addition, the ratio of phosphonic acid residues in which hydrogen is present to the total number of phosphonic acid residues can be arbitrarily designed. Assuming that the number of phosphonic acid residues present in phosphorus-containing polyaniline is 100%, the ratio of phosphonic acid residues in which hydrogen is present is, for example, 10% or more, 20% or more, 30% or more, 40% or more, 50%. It is possible to select from the above, 60% or more, 70% or more, 80% or more, 90% or more, or 95% or more. Alternatively, it may be 100%. It can also be designed to suppress the number of phosphonic acid residues in which hydrogen is present, if for some reason it is desired to control the hydrogen content. In such a case, assuming that the number of phosphonic acid residues present in the phosphorus-containing polyaniline is 100%, for example, the ratios are 95% or less, 90% or less, 85% or less, 80% or less, 75% or less, Alternatively, it can be designed to be 70% or less.

(Ion exchange)
For the conductive polyaniline, the reaction material may be adjusted so that the desired amount of phosphonic acid residue in which hydrogen is present is introduced during the phosphorification. For example, the type and amount of phosphite compound can be selected so that the desired amount of phosphonic acid residue with the desired amount of hydrogen is introduced.

Further, the polyaniline obtained by the method of the present invention may be subjected to ion exchange to adjust the amount of doping, if necessary. Ion exchange can be performed with an acidic aqueous solution, an ion exchange resin, or the like.

That is, when the amount of hydrogen in the obtained phosphonic acid or phosphonic acid monohydrogen salt of the obtained polyaniline is less than the desired amount as a whole polymer, the metal ion, pyridinium ion or ammonium ion bonded to the phosphonic acid is converted into a hydrogen ion. By exchanging ions, the effect of doping can be enhanced.

Conversely, if the amount of hydrogen in the phosphonic acid or phosphonic acid monohydrogen salt of the polyaniline obtained by polymerization is more than the desired amount for the polymer as a whole, hydrogen ions of the phosphonic acid or phosphonic acid monohydrogen salt may be used. The effect of doping can be reduced by ion exchange with ions (for example, alkali metal ion, ammonium ion, pyridinium ion, etc.).

Ion exchange can be performed after synthesizing polyaniline. It can be performed at the same time as the above purification operation, and may be performed before the purification operation or after the purification operation. For example, when purification is performed by filtration, if the column to be filtered is filled with an ion exchange resin, ion exchange can be performed at the same time as purification by filtration.

As a method of ion exchange, a conventionally known method of ion exchange can be used.

[Phosphorus-containing polyaniline ester]
In one embodiment of the invention, the phosphorus-containing polyaniline is a phosphorus-containing polyaniline ester having an ester bond. Phosphorus-containing polyaniline esters are particularly useful as intermediates for the production of conductive polyanilines.

Phosphor-containing polyaniline esters have one or two ester bonds at least one phosphonic acid residue in the molecule. That is, one or both of M ¹ and M ^{2 in} the phosphonic acid residue R ^{p present in each A 1} of the above general formula (1) is an alkyl group having 1 to 15 carbon atoms and 7 carbon atoms. It is selected from an aralkyl group of ~ 34 or an aryl group having 6 to 30 carbon atoms to form an ester bond. A ^{structure in which only one of M 1} and M ² is an ester is referred to herein as a monoester. Structures in which both M ¹ and M ² are esters are referred to herein as diesters.

Since the phosphorus-containing polyaniline ester is basically the same as the above-mentioned phosphorus-containing polyaniline except that it has an ester, the above description of the phosphorus-containing polyaniline basically also applies to the above-mentioned phosphorus-containing polyaniline ester.

Both monoesters and diesters can be used as intermediates for producing conductive polyaniline, but diesters are preferable in terms of ease of synthesis and the like. ^{As the types of M 1} and M ² forming the ester, alkyl or aralkyl is preferable, and alkyl is more preferable. Specific examples include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group and pentadecyl group. Can be mentioned. ^{The types of M 1} and M ² forming the ester are more preferably alkyl having 1 to 6 carbon atoms, and particularly preferably alkyl having 1 to 4 carbon atoms.

In one embodiment where all phosphonic acid residues in the phosphopolyaniline ester are absent, i.e. all esters are monoesters, at least one phosphonic acid residue is other than an ethyl ester. It is an ester.

Phosphorus-containing polyaniline esters are, in one preferred embodiment, obtained by phosphonating polyaniline compounds. For example, it is obtained by reacting a polyaniline compound with phosphite. Specific examples of the phosphite to be reacted include the phosphite of the general formula (3) and the phosphite of the general formula (4). In the phosphite of the general formula (3), ^{at least one of M 3 to} M ⁵ is an alkyl group having 1 to 15 carbon atoms, an aralkyl group having 7 to 34 carbon atoms, or an aryl having 6 to 30 carbon atoms. By using the group, or in the phosphite of the general formula (4) ^{, at least one of M 6 to} M ⁷ is an alkyl group having 1 to 15 carbon atoms and an aralkyl group having 7 to 34 carbon atoms. Alternatively, an ester can be introduced into the obtained phosphorus-containing polyaniline by using an aryl group having 6 to 30 carbon atoms.

The phosphorus-containing polyaniline ester can also be represented by the above-mentioned general formula (1):
-(A ¹ ) _k- (1)
Each A ¹ independently has m phosphonic acid residues R ^p and n substituents R.
The phosphonic acid residue R ^p is expressed by the following formula:

However, the phosphonic acid residue having an ester bond to at least one of the k aniline monomer residues A ¹ in the phosphorus-containing polyaniline ester is present. The number of phosphon residues in which the ester is present can be arbitrarily selected. The ratio of phosphone residues in which the ester is present is, for example, 10% or more, 20% or more, 30% or more, 40% or more, 50%, assuming that the number of aniline monomer residues present in the phosphorus-containing polyaniline ester is 100%. It is possible to select from the above, 60% or more, 70% or more, 80% or more, 90% or more, or 95% or more. Alternatively, it may be 100%. It can also be designed to suppress the number of phosphonic acid residues in which the ester is present, if for some reason it is desired to control the ester content. In such a case, for example, the ratio can be designed to be 95% or less, 90% or less, 85% or less, or 80% or less.

Further, the phosphodiester residue having an ester bond may be a monoester or a diester as described above. For example, all of the phosphonic acid residues having an ester bond in the phosphorus-containing polyaniline ester may be monoesters, or all may be diesters. Further, both the phosphonic acid residue of the monoester and the phosphonic acid residue of the diester may be present. A phosphopolyaniline ester containing both a phosphonic acid residue of a monoester and a phosphonic acid residue of a diester can be produced, for example, by using two or more kinds of phosphite compounds. The number of phosphonic acid residues of the monoester and the number of phosphonic acid residues of the diester in the phosphopolyaniline-containing ester can be arbitrarily selected. For example, assuming that the total number of monoester phosphodies and the number of diester phosphodies is 100%, the number of diesters is 10% or more, 20% or more, 30% or more, 40% or more, 50% or more. , 60% or more, 70% or more, 80% or more, or 90% or more can be selected. It is also possible to select the number of monoesters from 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more. is there.

(Polyaniline obtained by hydrolysis)
When the above-mentioned phosphorus-containing polyaniline ester is hydrolyzed, the ester portion is decomposed to obtain an ester-free phosphorus-containing polyaniline. The ester-free phosphorus-containing polyaniline thus obtained is useful as a proton-conducting and conductive polymer.

(fuel)
When the reaction gas is supplied to the fuel cell of the present invention, the following electrochemical reactions mainly occur to generate DC electric power.
Negative electrode: 2H ₂ → 4H ⁺ + 4e ^{−
_{Cathode: O 2 + 4H + + 4e}} - → 2H 2 O
In platinum, almost 100% 4-electron reduction occurs, but in other catalysts, for example, heteroatom-doped carbon catalysts, _{2-electron reduction of O 2} + 2H ⁺ + 2e ⁻ → H ₂ O ₂ can occur at the same time. Are known.

An oxidation reaction in which protons are generated occurs on the negative electrode side, and a reduction reaction of oxygen molecules occurs on the positive electrode side using the catalyst of the present invention. Examples of the fuel that can be adopted in the present invention as a proton source required for the reduction reaction on the positive electrode side include hydrogen gas, methanol, ethanol, 1-propanol, dimethyl ether, ammonia and the like, but hydrogen is preferable.

(binder)
In the present specification, the binder means a binder for binding a catalyst to form a catalyst layer in a polymer electrolyte fuel cell. In polymer electrolyte fuel cells, protons pass through the binder and come into contact with the catalyst. Conventional binders are mainly manufactured using solid electrolytes.

In the fuel cell using the catalyst of the present invention, a conventional binder having proton conductivity can be used. Examples of such a binder include PTFE (Polytellafluoroetylene), PVDF (Polyvinylidene fluoride), Nafion-based polymer, PA (Polyamide) -based polymer, PI (Polyamide) -based polymer, PVA (Polyvinylidene) polymer, and PVA (Polyvinylidene fluoride) polymer. Examples include based polymers and polyazole-based polymers, which can be used alone or in combination of two or more.

The present invention also provides, in one embodiment, a novel binder using polyaniline. The binder using polyaniline used in the present invention has an advantage that it is environmentally friendly because it does not contain halogen. Further, the polyaniline binder of the present invention has electrical conductivity in addition to proton conductivity, and prevents a phenomenon in which a catalyst wrapped in the binder and isolated from the electrode is generated, which causes a decrease in catalyst utilization rate. Can be done. The binder of the present invention may be used for the anode electrode layer or the cathode electrode layer.

In the fuel cell of the present invention, the catalyst layer may be formed by using the catalyst of the present invention and the conventional binder, or the catalyst layer may be formed by using the conventional catalyst and the binder of the present invention. A catalyst layer may be formed using a catalyst and the binder of the present invention.

(catalyst)
The catalyst of the present invention can obtain the desired performance by calcining polyaniline having a specific structure. The catalyst of the present invention has a function of catalyzing a reduction reaction. The catalyst of the present invention is useful, for example, using the oxygen reduction reaction of a polymer electrolyte fuel cell as a catalyst.

In the catalyst of the present invention, in one embodiment, the catalytic activity is improved by adding a bipyridine compound or a metal compound to polyaniline.

(Catalyst manufacturing method)
The phosphorus-containing polyaniline can be preferably calcined to obtain a catalyst as a phosphorus-containing polyaniline calcined product. Further, it is preferable to produce a catalyst by performing a step of adding a pipyridine compound, a step of adding a metal compound, a pulverization step, an acid immersion step, or the like, if necessary.

(Bipyridine compound)
In the present specification, the bipyridine compound refers to bipyridine and substituted bipyridine.

Bipyridine compounds that can be preferably used in the catalyst of the present invention include 1- (4-pyridyl) piperazine, 2- (4-piperidinyl) pyridine, 2,2-bipyridyl, 2,3-bipyridyl, 2,4-bipyridyl, 4 , 4-bipyridyl, 1- (4-pyridyl) pyridinium chloride, 1- (4-pyridyl) pyridinium hydrochloride, 1- (4-pyridyl) pyridinium-n-hydrate, 6-bromo-2,2-bipyridine, 5 -Bromo-2,3-bipyridine, 5-bromo-2,4-bipyridine, 4,4-dibromo-2,2-bipyridine, 6,6-dibromo-2,2-bipyridine, 2,2-dipyridyl-N , N-dioxide, 6,6-diamino-2,2-bipyridine, 4,4-dimethyl-2,2-bipyridyl, 5,5-dimethyl-2,2-bipyridyl, 4,4-bis (chloromethyl) -2,2-bipyridine, 2,2-bipyridine-3,3-dicarboxylic acid, 2,2-bipyridine-4,4-dicarboxylic acid, 2,2-bipyridine-5,5-dicarboxylic acid, 4,4- Diethyl-2,2-bipyridyl, 4,4-dinonyl-2,2-dipyridyl, 2,6-bis (2-pyridyl) -4 (1H) -pyridone, 2,2: 6,2-terpyridine, 4- Chloro-2,2: 6,2-terpyridine, 4-bromo-2,2: 6,2-terpyridine, 4-hydroxy-2,2: 6,2-terpyridine, trimethyl-2,2: 6,2- Tarpyridine-4,4,4-tricarboxylate, 4,4,54-triethyl-2,2: 6,2-terpyridine, 4- (4-bromophenyl) -2,2: 6,2-terpyridine, 5 -Phenyl-2,2-bipyridine, 5-phenyl-2,3-bipyridine, 5-phenyl-2,4-bipyridine, 5- (4-chlorophenyl) -2,2-bipyridine, 5- (4-chlorophenyl) -2,3-bipyridine, 5- (4-chlorophenyl) -2,4-bipyridine, 5- (4-bromophenyl) -2,3-bipyridine, 5- (4-bromophenyl) -2,4-bipyridine And so on.

(Catalyst metal)
Further, in one embodiment, a metal compound containing a catalytic metal can be added to the phosphorus-containing polyaniline of the present invention. It is more preferable to add a metal compound because it enhances the effect of catalytic activity.

As the metal in the metal compound to be added, known transition metal elements can be used. For example, Group 4 elements such as titanium, zirconium and hafnium, Group 5 elements such as vanadium, niobium and tantalum, Group 6 elements such as chromium, molybdenum and tungsten, Group 7 elements such as manganese, technetium and ruthenium, iron and cobalt, Select at least one of the iron group elements such as nickel, platinum group elements such as platinum, iridium, osmium, palladium, rhodium and ruthenium, copper group elements such as copper, silver and gold, and group 12 elements such as zinc, cadmium and mercury. Can be done.

In the present invention, since a reduction catalyst having catalytic activity is inexpensively and easily provided, among the above, titanium, zirconium, vanadium, hafnium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, renium, iron, etc. It is preferable to use non-noble metal elements such as cobalt, nickel and zinc, and iron group elements such as iron, cobalt and nickel are more preferable.

When the phosphorus-containing polyaniline of the present invention is mixed with the metal compound containing the catalyst metal and the mixture is calcined, the metal element coordinates with nitrogen, oxygen and phosphorus to form a complex, and thus oxygen reduction. A reduction catalyst having better characteristics can be produced. The metal compound used is not particularly limited, but is a solid or liquid metal, a metal halide, a hypohalogenate metal salt, a halogenate metal salt, a perhalogenate metal salt, a metal oxide, a metal peroxide, or a metal nitrite. Salt, metal nitrate, metal carbonate, peroxometal carbonate, metal carboxylate, metal sulfite, metal sulfide, metal sulfate, metal persulfate, metal thiosulfate, metal hypophosphite, sub At least one can be selected from a metal phosphate metal salt, a metal phosphate metal salt, a metal hydroxide, an inorganic metal complex, an organic metal complex, and a metal organic compound. In the present specification, the solid or liquid metal, that is, a metal alone is also referred to as a metal compound.

Of these, metal halides, hypohalogenate metal salts, halogenate metal salts, perhalogenate metal salts, sub-metal halides, hypohalogenate metal salts, metal halides, from the viewpoint of ease of handling, dispersibility in water or organic solvents, and solubility. Metal nitrate, metal nitrate, metal carbonate, metal carboxylate, metal sulfide, metal sulfite, metal sulfate, metal persulfate, metal thiosulfate, metal hypophosphite, metal phosphite Salts, metal phosphate salts, metal hydroxides and organic metal complexes are preferred.

Specific examples of preferred metal compounds include:
Iron (II) chloride, iron (III) chloride, iron (II) bromide, iron (III) bromide, iron (II) sulfide, iron (III) sulfide, iron (II) sulfate, iron (III) sulfate, Iron (II) Nitrate, Iron (III) Nitrate, Potassium Hexacyano (II), Potassium Hexacyano (III), Iron (II) Oxide, Iron (III) Sulfate, Iron (II) Phosphate, Phosphorus Iron (III) acid, ferrocene, iron oxide (II), iron (III) oxide, triiron tetroxide, iron (II) hydroxide, iron (III) hydroxide, iron (II) acetate, iron (III) acetate , Iron compounds such as iron (II) lactate, iron (III) lactate, iron (II) acetylacetonate, iron (III) acetylacetonate;
Nickel chloride (II), nickel bromide (II), nickel sulfide (II), nickel sulfate (II), nickel nitrate (II), nickel oxalate (II), nickel phosphate (II), nickelocene, nickel oxide ( Nickel compounds such as II), nickel hydroxide (II), nickel acetate (II), nickel lactate (II), nickel (II) acetylacetonate;
Chromium Chloride (II), Chromium Chloride (III), Chromium Bromide (II), Chromium Bromide (I)
II), chromium sulfide (III), chromium sulfate (III), chromium nitrate (III), chromium oxalate (III), chromium phosphate (III), chromium oxide (II), chromium oxide (III), chromium oxide ( Chromium compounds such as IV), chromium oxide (VI), chromium hydroxide (III), chromium acetate (II), chromium acetate (III), chromium lactate (III);
Cobalt chloride (II), cobalt chloride (III), cobalt bromide (II), cobalt bromide (III), cobalt sulfide (II), cobalt sulfate (II), cobalt sulfate (III), cobalt nitrate (II), Cobalt nitrate (III), cobalt oxalate (II), cobalt phosphate (II), cobaltene, cobalt oxide (II), cobalt oxide (III), tricobalt tetraoxide, cobalt hydroxide (II), cobalt acetate ( Cobalt compounds such as II), cobalt lactate (II), cobalt (II) acetylacetonate, cobalt (III) acetylacetonate;
Vanadium chloride (II), vanadium chloride (III), vanadium chloride (IV), vanadium bromide (II), vanadium bromide (III), vanadium bromide (IV), vanadium sulfide (III), vanadium sulfate (IV) , Vanadium oxalate (IV), vanadium metallocene, vanadium oxide (V), vanadium acetate, vanadium citrate, vanadium (IV) acetylacetonate and other vanadium compounds;
Manganese chloride (II), manganese bromide (II), manganese sulfide (II), manganese sulfate (II), manganese nitrate (II), manganese oxalate (II), manganese hydroxide (II), manganese acetate (II) , Manganese compounds such as manganese lactate (II), manganese (II) acetylacetonate, and manganese (III) acetylacetonate.

Among these compounds, iron (II) chloride, iron (III) chloride, iron (II) sulfate, iron (III) sulfate, iron (II) nitrate, iron (III) nitrate, iron (II) hydroxide, water Iron (III) Oxide, Iron (II) Acetate, Iron (III) Acetate, Nickel Chloride (II), Nickel Sulfate (II), Nickel Nitrate (II), Nickel Hydroxide (II), Nickel Acetate (II), Chloride Cobalt (II), cobalt chloride (III), cobalt sulfate (II), cobalt sulfate (III), cobalt nitrate (II), cobalt nitrate (III), cobalt hydroxide (II), cobalt acetate (II) are more preferable. , Iron (II) chloride, Iron (III) chloride, Iron (II) acetate, Iron (III) acetate, Nickel chloride (II), Nickel acetate (II), Cobalt chloride (II), Cobalt chloride (III), Acetate Cobalt (II) is more preferred.

The above metal compounds may be used alone or in combination of two or more.

(Acid immersion)
In one embodiment, the phosphorus-containing polyaniline of the present invention may be treated with an acid solution. It is more preferable to treat the phosphorus-containing polyaniline of the present invention with an acid solution because it can be expected to obtain a reduction catalyst having a further enhanced effect of catalytic activity.
Hereinafter, acid immersion refers to a step of performing treatment with an acid solution.

The above treatment method is not particularly limited, but specifically, acid immersion can be performed by immersing phosphorus-containing polyaniline in an acid solution for a certain period of time. It is not necessary to stir well during acid immersion, and when stirring, it may be shaken lightly by hand, strongly shaken, a rotor may be used, or a stirring rod may be used. Often, as an operation instead of stirring, an operation of heating the acid solution to perform reflux, an operation of irradiating the acid solution with ultrasonic waves, and an operation of irradiating the acid solution with microwaves may be performed.

The temperature at which the acid immersion is performed is not particularly limited, and the acid immersion can be arbitrarily performed within a temperature range equal to or higher than the melting point of the solution and lower than the boiling point. Acid immersion may be performed at a high temperature in order to increase the catalytic activity, and acid immersion at a low temperature can also enhance the catalytic activity. Acid immersion may be performed at a constant temperature as long as it is within the above temperature range, and heating and cooling may be performed during acid immersion.

The concentration of the acid is not particularly limited, but it is preferable to use a diluted acid in order to be easy to handle and to suppress the decomposition of phosphorus-containing polyaniline. Specifically, those having a concentration of 20 mol / L or less, 10 mol / L or less, 5 mol / L or less, or 1 mol / L or less can be used, and 0.0001 mol / L or more and 0.0005 mol / L or more. , 0.001 mol / L or more, 0.005 mol / L or more, 0.01 mol / L or more, or 0.05 mol / L or more can be used, and 10 mol / L or less, 5 mol / L or less, Alternatively, 1 mol / L or less, 0.001 mol / L or more, 0.005 mol / L or more, 0.01 mol / L or more, or 0.05 mol / L or more is preferable, and 5 mol / L or less, or 1 mol / L or less, or More preferably, it is 0.01 mol / L or more, or 0.05 mol / L or more.

The type of acid used as the acid solution is not particularly limited, and known inorganic acids, carboxylic acids, and ion exchange resins can be used. Specifically, inorganic acids such as hydrochloric acid, nitrite, nitrate, sulfite, sulfuric acid, thiosulfate, hypophosphoric acid, phosphite, phosphoric acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid. , Capricic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, benzoic acid, benzenesulfonic acid, salicylic acid, phthalic acid, isophthalic acid, terephthalic acid and other carboxylic acids, strongly acidic cation exchange resin, weakly acidic An ion exchange resin such as a cation exchange resin can be used. These may be used alone or in combination of two or more.

The type of solvent used as the acid solution is not particularly limited, but water, a protic and aprotic organic solvent, and an aprotic organic solvent can be used. Methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, tert-butyl alcohol and the like can be selected as the protic organic solvent, and acetone, ethyl methyl ketone and acetyl acetone can be selected as the aprotic organic solvent. , 2,5-Hexanedione, diacetyl, tetrahydrofuran, 1,4-hexanediol, acetonitrile, dimethylformamide, dimethylsulfoxide and the like can be selected. These may be used alone or in combination of two or more.

The time for acid immersion is not particularly limited, and may be 10 minutes or more, 30 minutes or more, 1 hour or more, 2 hours or more, 4 hours or more, or 6 hours or more. Further, if necessary, it may be 10 hours or less, 8 hours or less, 6 hours or less, 4 hours or less, 2 hours or less, or 1 hour or less.

Before and after the acid immersion, washing with water may be performed. The method for washing the phosphorus-containing polyaniline with water can be carried out by the above-mentioned treatment method, temperature and time. A reduction catalyst having high catalytic activity can be obtained without washing with water, but washing with water is preferable because excess acid and ionic components remaining on the surface of phosphorus-containing polyaniline can be removed. The water used for cleaning is not particularly limited, but it is preferable to use deionized water for the above-mentioned reasons because the cleaning effect is high. Cleaning with water is preferably performed after acid immersion.

Both the acid solution and the water liquid can be removed by a known method after the acid immersion and washing are completed. As a specific method, a method of removing by suction filtration using a Büchner funnel lined with filter paper, a method of removing by vacuum drying, a method of allowing the liquid to stand still, and a method of removing the supernatant can be used. The number of times of acid immersion and washing with water is not particularly limited, and if necessary, the operation of removing the liquid after the acid immersion and cleaning may be omitted.
After removing the liquid by the above method, the phosphorus-containing polyaniline can be dried, if necessary. A known method can be used for drying, and specifically, there are a method of exposing the liquid to a temperature environment around the boiling point of the liquid, a method of putting the liquid in a closed container and drying it in a vacuum state, and a method of combining these. Drying can also be performed by firing after removing the liquid.

(Baking)
When producing the catalyst of the present invention, any conventionally known method can be adopted as a method for calcining polyaniline. When the catalyst of the present invention contains a bipyridine compound or a metal compound, it is preferable to add the compound before firing.

The atmosphere for firing the polyaniline of the present invention is preferably a non-oxidizing atmosphere, and particularly preferably an argon atmosphere. The firing temperature is preferably 600 to 1200 ° C, more preferably 700 to 1100 ° C. The phosphorus-containing polyaniline to be acid-immersed may be before firing, or may be a phosphorus-containing polyaniline fired body that has been fired one or more times.

The firing time is not particularly limited, and is 30 seconds or more, 1 minute or more, 3 minutes or more, 5 minutes or more, 10 minutes or more, 30 minutes or more, 1 hour or more, 2 hours or more, 4 hours or more, or It can be 6 hours or more. Further, if necessary, it may be 10 hours or less, 8 hours or less, 6 hours or less, 4 hours or less, 2 hours or less, 1 hour or less, or 30 minutes or less. If the firing time is too long, the amount of the fired body recovered may be small, and it may be difficult to recover the fired body.

According to one preferred embodiment, it is preferable to perform firing until the phosphorus-containing polyaniline reaches a certain carbonization degree, and it is preferable to set the time until such a state is reached as the firing time. For example, in a preferred embodiment, firing can be carried out until the weight of the polyaniline is reduced to some extent by thermal decomposition. The weight loss rate of polyaniline can be appropriately selected. For example, it is possible to select from 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more. Further, the weight loss rate can be designed to be 95% or less, 90% or less, 85% or less, 80% or less, 75% or less, or 70% or less. For example, in one preferred embodiment, firing can be carried out until thermal decomposition is similar to that of firing at 900 ° C. for 5 minutes.

Here, the weight loss rate is calculated based on the formula (weight loss rate) = (numerator) ÷ (denominator) × 100. The numerator and denominator are as follows.
(Numerator): Weight loss (denominator): Total weight of polyaniline and additives (metal salts and bipyridine compounds) before firing (however, solvent is excluded).
(Weight reduction rate (%)) =
(1- (Weight of fired body after firing) / (Total weight of polyaniline and additives (metal salt and bipyridine compound) before firing (excluding solvent))) x 100
The apparatus for firing is not particularly limited. A device that can be sealed to some extent during heating is preferable. If it can be sealed to some extent, it is preferable because it is easy to maintain the inside in a preferable atmosphere (for example, a non-oxidizing atmosphere). A conventionally known oven or the like can be used. For example, an electric furnace can be used. However, since the pressure in the apparatus may increase rapidly due to the thermal decomposition reaction occurring in the electric furnace, an apparatus capable of releasing the pressure in such a case is preferable. For example, an intake port and an exhaust port are attached to a closed reactor, and a gas (for example, argon gas) for maintaining a non-oxidizing atmosphere is flowed from the intake port and the exhaust port to maintain the internal non-oxidizing atmosphere. However, a device capable of releasing the pressure from the intake port or the exhaust port when the pressure increases is preferable.

(Crushing)
The phosphorus-containing polyaniline and the phosphorus-containing polyaniline fired product may or may not be pretreated and post-treated when the acid immersion is performed. The method of pretreatment and posttreatment is not particularly limited, and examples thereof include pulverizing a phosphorus-containing polyaniline-containing and a phosphorus-containing polyaniline-containing calcined product. Specifically, the crushing method is a method of crushing by putting a phosphorus-containing polyaniline and a phosphorus-containing polyaniline fired body in a mortar and crushing with a pestle, and crushing by putting in a screw cap test tube and crushing with a round bottom glass rod. A method of crushing by putting it in a crusher such as a ball mill, a jet mill, or an air flow crusher can be used.

The reduction catalyst of the present invention exhibits high oxygen reduction activity without pretreatment and posttreatment by pulverization, but by performing pretreatment and posttreatment by pulverization, the particle size of the phosphorus-containing polyaniline and the phosphorus-containing polyaniline fired product is obtained. Is smaller and the surface area is improved, which is more preferable because the effect of catalytic activity by acid immersion can be further enhanced.

As the steps to be performed to obtain a reduction catalyst having high oxygen reduction activity from the phosphorus-containing polyaniline of the present invention, embodiments of each step of addition of a bipyridine compound, addition of a catalytic metal, acid immersion, firing, and pulverization have been mentioned. At least one or more of these steps may be performed as required, and at least two or more of these steps may be selected from the steps of adding the bipyridine compound, adding the catalyst metal, soaking in acid, and washing with water and performing at the same time. .. The order of these steps is not particularly limited, but it is more preferable to select the firing step and the pulverization step at the final stage of the steps because a reduction catalyst having higher oxygen reduction activity can be obtained. Further, the firing step may be performed twice or more, and in this case, the step of adding the metal compound or the bipyridine compound is preferably performed before the first firing step. Further, even when the firing step is performed twice or more, it is preferable to perform the firing step at the final stage of the step, and it is more preferable to perform the crushing step after that as necessary. A more preferable step is to carry out a pulverization step after the final firing step.

As a specific process order,
1. 1. Crushing process → Addition of bipyridine compound → Baking process 2. Acid immersion step → Addition step of metal compound and bipyridine compound → Firing step 3. Metal compound addition process → firing process 4. Metal compound addition process → firing process → acid immersion process → firing process → crushing process,
5. Examples thereof include a step of acid immersion and addition of a metal compound → a firing step → a crushing step.

The catalyst according to the present invention produced as described above has oxygen reduction characteristics and can be used as a positive electrode catalyst for a fuel cell without using a catalyst metal such as platinum. Further, the binder according to the present invention can be used as a material for a fuel cell because polyaniline exhibits excellent proton conductivity. Further, since the binder of the present invention also has conductivity (electrical conductivity), it can be suitably used as a binder for a fuel cell.

(Battery manufacturing method)
The method for manufacturing a battery using the catalyst of the present invention is not particularly limited. Various conventionally known methods can be used as a method for producing PEFC. For example, a catalyst can be mixed with a binder to form an electrode layer, which can be used as a positive electrode or a negative electrode and combined with other members of the battery to form a battery.

When forming the electrode layer, for example, a binder solution is prepared using a binder such as Nafion and, if necessary, a solvent, and the catalyst prepared by the above method is added to the binder solution to prepare a catalyst ink. Is available, and the catalyst ink is applied onto a base material and dried.

When the catalyst layer is formed using the binder of the present invention, a conventionally known catalyst can be used as the catalyst.

When the binder of the present invention is used for the positive electrode catalyst layer, the catalyst is, for example, an oxygen reduction catalyst composed of particles composed of a catalyst metal and a catalyst carrier. As the catalyst metal, for example, platinum, gold, copper, palladium, rhodium, ruthenium, iridium, osmium, renium, and two or more alloys thereof can be used. As the catalyst carrier, for example, carbon (for example, carbon black) or the like can be used.

When the binder of the present invention is used for the negative electrode catalyst layer, the catalyst is, for example, a catalyst composed of particles composed of a catalyst metal and a catalyst carrier, which promotes hydrogen ionization. As the catalyst metal, for example, platinum, gold, copper, palladium, rhodium, ruthenium, iridium, osmium, renium, and two or more alloys thereof can be used. As the catalyst carrier, for example, carbon (for example, carbon black) or the like can be used.

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

[Electrochemical measurement]
(apparatus)
The electric furnace used for firing the sample in the following examples is FT-01X manufactured by FULL-TECH. The data on the activity evaluation of the oxygen reduction reaction can be found on the BAS electrochemical analyzer ALS608E, which can record the current change by changing the potential of the working electrode using a voltage controller, and the electrode activity of the oxygen reduction reaction. The measurement was performed using the rotating ring disk electrode device RRDE-3A to be analyzed.

(electrode)
An oxygen-saturated 0.1 M phosphoric acid aqueous solution is used as the electrolytic solution, a silver / silver chloride (3M NaCl) electrode is used as the reference electrode, a platinum electrode is used as the counter electrode, and a glassy carbon disk electrode (outer diameter 12 mm) is used as the working electrode. Of these, the diameter of the electrode portion (3 mm or 4 mm) was used.

(Preparation of Nafion binder solution)
The Nafion binder solution used for preparing the catalyst ink was prepared by the following procedure. First, 25 mL of a Nafion binder solution was prepared by adding 595 μL (Nafion equivalent amount: 27.5 mg) of a 5 wt% Nafion dispersion (manufactured by Sigma-Aldrich, 527084-25ML) to a deionized water / isopropanol mixed solution having a volume ratio of 15/16. ..

(Preparation of catalyst ink)
Catalyst inks were prepared as described in each example. As the disc electrode used for preparing the catalyst ink, a disc electrode that had been sufficiently polished with polishing alumina (diameter 0.05 μm) and rinsed well with deionized water was used.

(Measuring method)
While rotating the disk electrode at 1600 rpm with a rotating ring disk electrode device, the potential was swept in the negative direction at a speed of 5 mV / s using an electrochemical analyzer, and the value of the current flowing through the working electrode was recorded. The reduction current is in the negative direction. Further, as comparative data, the data measured without applying the catalyst ink to the disc electrode is shown in each figure as a blank.

(Synthesis Example 1)
(Synthesis of poly (2-methoxyaniline-5-phosphonic acid) (hereinafter referred to as PMAP))
PMAP was synthesized according to the following scheme with reference to the international publication WO2014 / 167818.

(1A) Synthesis of compound (6) After drying the inside of the flask, 4-bromo-2-nitroanisole 804 mg (3.47 mmol), Na ₂ CO ₃ 405 mg (3.82 mmol), Pd (OAc) _{2 under a nitrogen atmosphere.} 78 mg (0.35 mmol), 0.9 mL (6.99 mmol) of diethyl phosphite, and 3 mL of xylene were added. The mixture was stirred at 120 ° C. for 24 hours, cooled to room temperature, the solids were filtered off with Celite, and the slag was washed with _{CH 2} Cl _2. The obtained filtrate and the washing liquid of the filter slag were mixed, the solvent was distilled off, and then the mixture was purified by column chromatography to obtain 807 mg of a yellow liquid. Then, Kugelrohr distillation (100 ° C./133Pa × 30 minutes) was carried out to distill off the remaining diethyl phosphite, and 689 mg of diethyl 4-methoxy-3-nitrophenylphosphonate (2. 38 mmol, yield 69%) was obtained.

(1B) Synthesis of compound (7) After drying the inside of the flask, 1.14 g (3.9 mmol) of diethyl 4-methoxy-3-nitrophenylphosphonate and 5 mL of methanol were added under a nitrogen atmosphere, and 5% Pd-C 88 mg (8 mg) ( After adding (containing 5 wt% of Pd in C), the mixture was stirred at room temperature to bring the inside of the system into a hydrogen atmosphere. After 4.5 hours, 5% Pd-C was further added and the mixture was stirred for 2 hours at room temperature to terminate the reaction. The obtained reaction mixture was filtered off with Celite, and the filtrate was evaporated to give 830 mg of a brown liquid, diethyl 3-amino-4-methoxyphenylphosphonate. Next, 5 mL (60 mmol) of 35% hydrochloric acid was added, and the mixture was kept at 90 ° C. for 15 hours to terminate the reaction. The solvent of the obtained reaction mixture was distilled off, and the solid was dried under reduced pressure of 133 Pa at room temperature to 672 mg (2.80 mmol, 2-step yield 72%) of 3-amino-4-methoxy of the target compound. A solid of phenylphosphonate was obtained. It was used as it was in the next reaction without further purification.

(1C) Synthesis of compound (8) 150 mg (0.63 mmol) of 3-amino-4-methoxyphenylphosphonate salt salt and 1.48 mL of water were placed in a flask, and 2.96 mL (2.96 mmol) of _{a 1M-NH 3 aqueous solution was placed.} After cooling to 3 ° C., 0.74 _{mL (0.93 mmol) of a 1.25 M- (NH 4} ) ₂ S ₂ O ₈ aqueous solution was added dropwise over 30 minutes. The resulting mixture was further stirred at 3 ° C. for 24 hours to terminate the reaction. The obtained reaction product was added to 50 mL of acetone to precipitate a solid, and the mixture was further stirred at room temperature for 30 minutes. The solid was filtered off with Kiriyama wax and washed with a few mL of methanol. The obtained solid was dried at 40 ° C. under a reduced pressure of 133 Pa to obtain 184 mg of a green solid of the target compound.

(Example of using PMAP as a binder)
(Example 1)
In order to investigate whether PMAP can be used as a binder instead of Nafion, the activity of the oxygen reduction reaction was evaluated using a commercially available platinum-supported carbon as a catalyst. First, 1.1 mg of PMAP synthesized in Synthesis Example 1 was suspended in 48 μL of a 5.6 M pyridine aqueous solution, and deionized water was added to prepare 1 mL of PMAP / pyridine binder solution. Here, pyridine was added in an amount of 0.5 equivalent to the monomer unit of PMAP in order to disperse PMAP well. 40 μL is taken from the prepared binder solution, and this is mixed with 2.4 mg of Pt / C (containing 10 wt% of Pt in C, hereinafter referred to as Pt / C (10 wt%)) powder and 50 μL of isopropanol, and then mixed. Deionized water was added to make 1 mL. A catalyst ink was prepared by irradiating the obtained mixture with ultrasonic waves for 3.5 hours. Next, 3 μL was taken from the catalyst ink, which was applied to a disk electrode and air-dried to prepare a measurement sample, and then the activity of the oxygen reduction reaction was evaluated. Incidentally, Pt / C (10wt%) and the supported amount of PMAP was respectively 51μg / cm ² and 2 [mu] g / cm ^2.

(Comparative Example 1)
40 μL of Nafion binder solution was taken, mixed with 2.4 mg of Pt / C (10 wt%) powder and 50 μL of isopropanol, and then deionized water was added to make 1 mL. A catalyst ink was prepared by irradiating the obtained mixture with ultrasonic waves for 3.5 hours. Next, 1.5 μL was taken from the catalyst ink, which was applied to a disk electrode and air-dried to prepare a measurement sample, and then the activity of the oxygen reduction reaction was evaluated. Incidentally, Pt / C (10wt%) and the supported amount of Nafion was respectively 51μg / cm ² and 1 [mu] g / cm ^2.

[Evaluation of oxygen reduction reaction activity of each binder]
The oxygen reduction reaction activity was evaluated by the measurement method described in "Electrochemical measurement". The result is shown in FIG. As a result of the measurement, it was found that PMAP showed the same binder performance as Nafion.

(Example using PMAP fired body as a catalyst)
(Example 2)
[Synthesis of PMAP fired body]
20.0 mg of PMAP synthesized in Synthesis Example 1 was placed in a mullite crucible (5 mL), covered, placed in an electric furnace, and fired under an argon air stream. The temperature was raised at a rate of 100 ° C./min from 5 minutes after the start of the argon gas flow, and held for 5 minutes after reaching 700 ° C., 800 ° C. or 900 ° C. Then, the heating was stopped and the electric furnace was cooled to obtain 11.8 mg, 10.2 mg, and 5.7 mg of glossy gray solids, respectively. Hereinafter, these samples will be abbreviated as PMAP700, PMAP800 and PMAP900, respectively.

[Evaluation of oxygen reduction reaction activity of PMAP calcined product]
The activity of the oxygen reduction reaction was evaluated for the PMAP calcined products (PMAP700, PMAP800, PMAP900) synthesized by the above method. The oxygen reduction reaction activity was measured by the measuring method described in "Electrochemical measurement". The result is shown in FIG.

As a result of the measurement, oxygen reduction activity was observed in all the samples, though not as much as Pt / C. It was found that as the calcination temperature of the sample increased, the oxygen reduction initiation potential shifted in the positive direction, and the oxygen reduction activity improved. As comparative data, the Pt / C data obtained in Comparative Example 1 is also shown.

(Example using PMAP / 4,4'-bipyridyl calcined product as a catalyst)
(Example 3)
[Synthesis of PMAP / 4,4'-bipyridyl calcined product]
N, N-dimethylformamide (DMF) was added to a mullite crucible (5 mL) containing 20.0 mg of PMAP and 1.9 mg of 4,4'-bipyridyl (0.5 equivalent to the monomer unit of PMAP) synthesized in Synthesis Example 1. 100 μL was added. The solid material was stirred while being crushed well with a glass rod, covered, placed in an electric furnace, and fired under an argon stream. The temperature was raised to 135 ° C. in 2 minutes from 5 minutes after the start of the gas flow, and the temperature was maintained for 5 minutes. Then, the temperature was raised to 210 ° C. in 2 minutes and held for 3 minutes. Then, the temperature was raised to 900 ° C. at a rate of 100 ° C./min and held for 5 minutes. Finally, the heating was stopped and the electric furnace was cooled to obtain 4.0 mg of a black solid. Hereinafter, the sample obtained here is abbreviated as PMAP / bpy / DMF / 900.

[Evaluation of oxygen reduction reaction activity of PMAP / 4,4'-bipyridyl calcined product]
The activity of the oxygen reduction reaction was evaluated for the PMAP / 4,4'-bipyridyl calcined product (PMAP / bpy / DMF / 900) synthesized by the above method. The oxygen reduction reaction activity was evaluated by the measurement method described in "Electrochemical measurement". The result is shown in FIG.

As a result of the measurement, oxygen reduction activity was observed, though not as much as Pt / C. Comparing with the data of PMAP900 obtained in Example 2, it was found that the oxygen reduction initiation potential was shifted in the positive direction, and the addition of 4,4'-bipyridyl improved the oxygen reduction activity. As comparative data, the Pt / C data obtained in Comparative Example 1 is also shown.

(Example of using a fired polyaniline (hereinafter referred to as PANI) as a catalyst)
(Comparative Example 2)
[Synthesis of PANI fired body]
PANI (manufactured by Sigma-Aldrich, 53689-10G, Mw: ~ 65,000) was used, and Catal. Lett. 2012, 142, 1244-1250. The synthesis was carried out with reference to the firing method of. 1.2 mL of deionized water was added to a mullite crucible (5 mL) to which 200.0 mg of PANI was added, and the mixture was well stirred, covered, placed in an electric furnace, and fired under an argon stream. The temperature was raised to 95 ° C. in 1 minute from 5 minutes after the start of the gas flow, and the temperature was maintained for 5 minutes. Then, the temperature was raised to 130 ° C. in 1 minute and held for 5 minutes. Then, the temperature was raised to 900 ° C. at a rate of 100 ° C./min and held for 5 minutes. Finally, the heating was stopped and the electric furnace was cooled to obtain 99.1 mg of a black solid. Hereinafter, the sample obtained here _{is abbreviated as PANI / H 2} O / 900.

[Evaluation of oxygen reduction reaction activity of PANI calcined product]
As a comparative example, the activity of the oxygen reduction reaction was evaluated for the PANI calcined product (PANI / H _{2 O / 900) synthesized by the above method.} The oxygen reduction reaction activity was evaluated by the measurement method described in "Electrochemical measurement". The result is shown in FIG.

As a result of the measurement, oxygen reduction activity was observed, though not as much as Pt / C. Comparing with the data of PMAP900 obtained in Example 2, it was found that the oxygen reduction starting potential was slightly shifted in the negative direction, and PMAP900 had a slightly higher oxygen reduction activity. As comparative data, the Pt / C data obtained in Comparative Example 1 is also shown.

(Synthesis Example 2)
Poly (diethyl aminophenylphosphonate)
Put the rotor in a container (φ34) for ChemiStation Personal Synthesizer PPV (manufactured by EYELA), polyaniline 1.81 g (5.0 mmol (aniline tetramer standard), SIGMA-ALDRICH: polyaniline (emeraldine base) weight average molecular weight about 10000) was added. Subsequently, 100 mL of NMP was added to the container and stirred. Then, ultrasonic waves were irradiated for 5 minutes. To this, 1.71 g (7.5 mmol) of ammonium persulfate was added, and the mixture was stirred at room temperature for 30 minutes. After 30 minutes, 900 μL (50 mmol) of deionized water was added, followed by 26.0 mL (155 mmol) of triethyl phosphate. This mixture is mixed with ChemiStation Personal.
The temperature was raised to 60 ° C. using a Synthesizer PPV (manufactured by EYELA), and stirring was continued. A reflux tube was attached to the device, and when the temperature was raised and the mixture was stirred, the device was air-cooled using the attached reflux tube. One hour after the temperature was raised, the reaction solution was poured into a conical beaker containing 1000 mL of deionized water. Then, a black-green solid was obtained by suction filtration. Subsequently, in order to perform dedoping, the obtained solid was placed in a conical beaker containing 400 mL of 0.15 mol / L ammonia water, stirred, and ultrasonically irradiated for 10 minutes. Then, a black-blue solid was obtained by suction filtration. Next, the dedoped solid was placed in a conical beaker containing 400 mL of deionized water, stirred, and ultrasonically irradiated for 10 minutes. Then, a black-blue solid was obtained by suction filtration. Further, the obtained solid was transferred to a conical beaker, 200 mL of diethyl ether was poured therein, the mixture was stirred, and suction filtration was performed to obtain a black-blue solid. The obtained solid was vacuum dried under heating (40 ° C.) overnight. The yield of the solid was 2.49 g.

(Synthesis of diethyl polyaniline phosphonate (hereinafter referred to as PANI-PDE))
(Synthesis Example 3)
Put the rotor in a container (φ34) for ChemiStation Personal Synthesizer PPS-CTRL1 (manufactured by EYELA), and add 214.5 mg of phospholated polyaniline (0.34 mmol (based on aniline tetramer), synthesized in Synthesis Example 2). It was. Subsequently, 20 mL of NMP was added to the container and stirred. Then, ultrasonic waves were irradiated for 5 minutes. 119.8 mg (0.53 mmol) of ammonium persulfate was added thereto, and the mixture was stirred at room temperature for 30 minutes. After 30 minutes, 63 μL (3.5 mmol) of deionized water was added, followed by 1.82 mL (10.9 mmol) of triethyl phosphate. The mixture was heated to 60 ° C. using ChemiStation Personal Synthesizer PPS-CTRL1 (manufactured by EYELA) and stirring was continued. A reflux tube was attached to the device, and when the temperature was raised and the mixture was stirred, the device was air-cooled using the attached reflux tube. One hour after the temperature was raised, the reaction solution was transferred to a 200 mL eggplant flask while being washed with deionized water. Then, the distillation apparatus was assembled and heated under reduced pressure to distill off the solvent. An alkaline trap was used to distill off the solvent. After distilling off most of the solvent, about 40 mL of toluene was added and ultrasonic waves were applied for 5 minutes. Then, the mixture was heated again under reduced pressure to distill off the solvent. Subsequently, deionized water was added to the solid in the eggplant flask, and suction filtration was performed to obtain a black-green solid. Subsequently, in order to perform dedoping, the obtained solid was placed in a conical beaker containing 200 mL of 0.15 mol / L ammonia water, stirred, and ultrasonically irradiated for 10 minutes. Then, a black solid was obtained by suction filtration. Next, the dedoped solid was placed in a conical beaker containing 200 mL of deionized water, stirred, and ultrasonically irradiated for 10 minutes. Then, a black solid was obtained by suction filtration. In addition, the obtained solid was washed with about 200 mL of diethyl ether. The obtained solid was vacuum dried under heating (40 ° C.) overnight. The yield of the obtained solid was 104.6 mg.

(Synthesis of polyaniline phosphonic acid (hereinafter referred to as PANI-PA))
(Synthesis Example 4)
A rotor was placed in a container (φ24) for ChemiStation Personal Synthesizer PPS-CTRL1 (manufactured by EYELA), and frame drying was performed. The inside of the reaction vessel was replaced with nitrogen, and 200 mg of phospholated polyaniline (0.33 mmol (based on aniline tetramer), which was synthesized in Synthesis Example 2) was added. To this, 20 mL (super dehydration) of acetonitrile and 2.2 mL (16.8 mmol) of trimethylsilyl bromide were added. The mixture was heated to 90 ° C. using ChemiStation Personal Synthesizer PPS-CTRL1 (manufactured by EYELA), stirred and reacted. 300 mL of deionized water was poured into a conical beaker, and three and a half hours after the start of the reaction, the reaction solution was added thereto while washing with deionized water. Then, using an alkaline trap, a black solid was obtained by suction filtration. The obtained solid was vacuum dried under heating (40 ° C.) overnight. The yield of the solid was 117.2 mg.

(Example of using PMAP / FeCl ₃ fired body and PMAP fired body as catalysts)
(Example 4)
[Synthesis of PMAP / FeCl ₃ calcined product and PMAP calcined product]
Add 20.0 mg of PMAP obtained in Synthesis Example 1 and FeCl ₃ / DMF solution (0.489M, 102 μL) to a mullite crucible (5 mL), stir well, cover, put in an electric furnace, and bake under an argon stream. Was done. The temperature was raised to 130 ° C. in 2 minutes from 5 minutes after the start of the argon gas flow, and the temperature was maintained for 5 minutes. Then, the temperature was raised to 180 ° C. in 2 minutes and held for 5 minutes. Then, the temperature was raised at a rate of 100 ° C./min, and the temperature was maintained for 5 minutes after reaching 900 ° C. Then, the heating was stopped and the electric furnace was cooled to obtain 11.0 mg of a gray solid. Hereinafter, the sample obtained here abbreviated as PMAP / FeCl _3/900. Further, the same operation was carried out using DMF (102 μL) instead of _{FeCl 3 / DMF solution to obtain 7.3 mg of a black solid.} Hereinafter, the sample obtained here is abbreviated as PMAP / 900.

(Example of using PANI-PDE / FeCl ₃ fired body and PANI-PDE fired body as catalysts)
(Example 5)
[Synthesis of PANI-PDE / FeCl ₃ calcined product and PANI-PDE calcined product]
Baking was carried out in the same procedure as in Example 4 except that 20.0 mg of PANI-PDE obtained in Synthesis Example 3 and a FeCl _{3 / DMF solution (0.489M, 129 μL) were used in a mullite crucible (5 mL).} 11.6 mg of gray solid was obtained. Hereinafter, the sample obtained here abbreviated as _{PANI-PDE / FeCl 3/900} . Further, the same operation was carried out using DMF (129 μL) instead of _{FeCl 3 / DMF solution to obtain 4.1 mg of a black solid.} Hereinafter, the sample obtained here is abbreviated as PANI-PDE / 900.

(Example of using PANI-PA / FeCl ₃ fired body and PANI-PA fired body as catalysts)
(Example 6)
[Synthesis of PANI-PA / FeCl ₃ calcined product and PANI-PA calcined product]
Baking was carried out in the same procedure as in Example 4 except that 20.0 mg of PANI-PA obtained in Synthesis Example 4 and a FeCl _{3 / DMF solution (0.489M, 157 μL) were used in a mullite crucible (5 mL).} 14.3 mg of gray solid was obtained. Hereinafter, the sample obtained here abbreviated as _{PANI-PA / FeCl 3/900} . Further, the same operation was carried out using DMF (157 μL) instead of _{FeCl 3 / DMF solution to obtain 8.5 mg of a black solid.} Hereinafter, the sample obtained here is abbreviated as PANI-PA / 900.

[Evaluation of oxygen reduction reaction activity of each fired product of Examples 4 to 6]
The activity of the oxygen reduction reaction was evaluated for each of the fired bodies of Examples 4 to 6 synthesized by the above method. The oxygen reduction reaction activity was evaluated by the measurement method described in "Electrochemical measurement". The results are shown in FIGS. 5 to 7, respectively.

As a result of the measurement, oxygen reduction activity was observed in all the samples, though not as much as Pt / C. When FeCl ₃ was added, the oxygen reduction starting potential was shifted in the positive direction, and the oxygen reduction activity was improved. As comparative data, the blank and Pt / C data obtained in Example 1 are also shown.

(Example 7)
[PMAP / FeCl ₃ calcined product that has been acid-immersed and refired]
PMAP _/ FeCl 3 /900(20.0mg, screw-top test tube were added one) was calcined in Example 4 (Maruemu, N-16) 0.5M dilute sulfuric acid (2.0 mL) was added, at 80 ° C. Refluxed for 2 hours. After allowing to cool to room temperature, the supernatant was removed using a Pasteur pipette. Deionized water (about 2 mL) was added thereto, and the mixture was irradiated with ultrasonic waves for 1 minute and allowed to stand. Then, the supernatant was removed again and washing was performed. This washing operation was repeated a total of 4 times, and then dried at 100 ° C. until the moisture disappeared to obtain 11.7 mg of a gray solid. Hereinafter, where the resulting sample is abbreviated as PMAP _/ FeCl _{3/900 /} acid immersion. PMAP _/ FeCl _{3/900 /} acid dipped (5.2 mg) placed in a mullite crucible (5 mL), it was placed in an electric furnace with a lid. The temperature was raised at a rate of 100 ° C./min from 5 minutes after the start of the argon gas flow, and held for 5 minutes after reaching 900 ° C. Then, the heating was stopped and the electric furnace was cooled to obtain 2.2 mg of a gray solid. Hereinafter referred obtained sample and the PMAP _/ FeCl 3/900 / acid immersion / refired here. The obtained solid was transferred to a screw cap test tube (Maruem, N-16) and carefully ground with a round bottom glass rod.

[Evaluation of oxygen reduction reaction activity of the calcined product that has been acid-immersed and refired in PMAP / FeCl _{3 calcined product]}
The activity of the oxygen reduction reaction was evaluated for the calcined product of _{the PMAP / FeCl 3} calcined product synthesized by the above method, which had been acid-immersed and refired. The oxygen reduction reaction activity was evaluated by the measurement method described in "Electrochemical measurement". The result is shown in FIG.

As a result of the measurement, an oxygen reducing activity equivalent to that of Pt / C was observed. It was found that when re-baking after soaking in acid, the oxygen reduction start potential shifts in the positive direction and the oxygen reduction activity is improved. As comparative data, the blank and Pt / C data obtained in Example 1 are also shown.

The catalyst of the present invention can be used as a reduction catalyst, particularly as an oxygen reduction catalyst for PEFCs.

The binder of the present invention can be used as a novel material that does not contain halogen and has proton conductivity and electrical conductivity for the electrode layer binder of PEFC.

As described above, the present invention has been illustrated using the preferred embodiment of the present invention, but the present invention should not be construed as being limited to this embodiment. It is understood that the invention should be construed only by the claims. It will be understood by those skilled in the art that from the description of specific preferred embodiments of the present invention, an equivalent range can be implemented based on the description of the present invention and common general technical knowledge. The patents, patent applications and documents cited herein are to be incorporated by reference in their content as they are specifically described herein. Understood.

Claims (4)

The following general formula (1):
-(A ¹ ) _k- (1)
A binder for polymer electrolyte fuel cells containing phospholated polyaniline represented by, wherein the binder is used.
A ¹ is an independently substituted aniline monomer residue or an unsubstituted aniline monomer residue, respectively.
Each of the substituted aniline monomer residues independently has m phosphonic acid residues R ^p and n substituents R on a 6-membered ring .
The phosphonic acid residue R ^p is expressed by the following formula:
During the ceremony
M ¹ and M ² are independently hydrogen atoms, alkyl groups having 1 to 15 carbon atoms, aralkyl groups having 7 to 34 carbon atoms, aryl groups having 6 to 30 carbon atoms, alkali metals, and alkaline earth metals. At least one selected from the group consisting of an ammonium group and a pyridinium group.
M ¹ and M ² may be the same or different,
However, at least one M ^{1 in the} polyaniline is a hydrogen atom.
If one of the M ¹ or M ² is an alkaline earth metal, one of the two O in R ^p groups ^- one of M ¹ or M ² have the said alkaline earth metal atom is bonded The structure is such that the other of the above does not exist, or the structure is such that the alkaline earth metal atom bridges the O ^{− of two R p groups.}
R is an independently halogen atom, an alkyl group having 1 to 15 carbon atoms, an aralkyl group having 7 to 34 carbon atoms, an alkoxy group having 1 to 15 carbon atoms, and an alkylthio group having 1 to 15 carbon atoms. It is at least one selected from the group consisting of an alkylamino group having 1 to 15 carbon atoms, a carboxyl group, a carboxylic acid ester group having 1 to 15 carbon atoms in the ester residue, a nitro group and a cyano group.
m is an integer of 1 to 4 independently,
n is an integer of 0 to 3 independently.
The sum of m and n is 4 or less independently for each aniline monomer residue.
k is an integer Ri der of 4-3000,
However, in the general formula (1), all of A ¹ to the k exists never aniline monomer residue unsubstituted,
Binder for polymer electrolyte fuel cells. The binder according to claim 1 , wherein the number of phosphonic acid residues introduced into the polyaniline is 10% or more with respect to the number of aniline monomer residues. A polymer electrolyte fuel cell comprising the binder according to claim 1 or 2. The method for producing the binder according to any one of claims 1 to 3.
The following general formula (2):
− (A ² ) _k − (2)
The 6-membered ring in the polyaniline compound represented by (1) is subjected to a phosphonation reaction with a phosphite compound to obtain a phosphonated polyaniline, which includes a step of forming a binder from the phosphonated polyaniline.
A ² is a substituted aniline monomer residue or an unsubstituted aniline monomer residue.
Each of the substituted aniline monomer residues independently has 1 to 3 substituents R.
R and k are the same as the definitions in claim 1 and
The phosphite compound has the following general formula (3):

(Here, M ^{3 to} M ⁵ may be the same or different, and independently have an alkyl group having 1 to 15 carbon atoms, an aralkyl group having 7 to 34 carbon atoms, and 6 to 6 carbon atoms. It is selected from the group consisting of 30 aryl groups, hydrogen atoms, alkali metals, alkaline earth metals, ammonium groups, and pyridinium groups, provided that one of M ^{3 to} M ⁵ is an alkaline earth metal. the two O ^- a do not one of the remaining two of said alkaline earth metal atom is bonded M ³ ~M ⁵ present structure).
Or general formula (4):

(Here, M ⁶ and M ⁷ may be the same, and independently, an alkyl group having 1 to 15 carbon atoms, an aralkyl group having 7 to 34 carbon atoms, and an aryl group having 6 to 30 carbon atoms, respectively. It is selected from the group consisting of a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, and a pyridinium group. However, when one of M ⁶ and M ⁷ is an alkaline earth metal, two O's are used. ^The structure is such that the alkaline earth metal atom is bonded to ^{− and the other of M 6} and M ⁷ does not exist.)
The method represented by.