JP2017136579A - Cathode catalyst for fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalyst and a binder with high performance.SOLUTION: There is provided a catalyst and a binder for fuel cell, containing a polyaniline burned body containing a phosphonic acid residue. There is provided a cathode catalyst having a catalyst activity performance at low cost easily without using conventional catalysts such as platinum by using a catalyst containing a polyaniline phosphonic acid burned body. The polyaniline phosphonic acid can also be used as a binder containing no halogen for electrode formation of the fuel cell. There is provided a fuel cell using the catalyst or the binder.SELECTED DRAWING: None

Description

  The present invention relates to catalysts and binders, and in particular to catalysts and binders for fuel cells. In one aspect, the present invention relates to a positive electrode catalyst for a fuel cell comprising polyaniline phosphonic acid or a fired body thereof having oxygen reduction properties.

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

In recent years, environmental pollution due to thermal power generation, hydroelectric power generation, or nuclear power generation, which is a supply source of electric energy, has become a serious problem. Therefore, development of a fuel cell that can extract electric energy from hydrogen energy has attracted attention. Hydrogen is obtained by decomposing water or a hydrocarbon compound, and the chemical energy contained in the unit weight is large. Further, water is generated by the oxidation reaction of hydrogen gas, and has an advantage that no harmful substances and CO ₂ which is a global warming gas are not generated.

  In a polymer electrolyte fuel cell (PEFC) using hydrogen gas as a negative electrode fuel and oxygen gas as a 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 the PEFC voltage drop. Therefore, the problem of the catalyst material used in PEFC is the development of a catalyst material having high oxygen reduction reaction activity.

  For example, Patent Document 1 below discloses a fuel cell electrode in which metal fine particles such as platinum are dispersedly supported on the pore surface walls of a porous carbon film. However, in the prior art including the following Patent Document 1, since expensive platinum is used as a catalyst, there is a problem that the cost is increased. Therefore, Patent Document 2 below discloses a fuel cell electrode using nitrogen-containing graphite. Non-Patent Document 1 below discloses a fuel cell electrode 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 of requiring a lot of labor and time because it includes a step of NaCl recrystallization and washing. Therefore, a catalyst that can be produced more simply is desired.

  Moreover, not only the battery electrode material but also a reduction reaction active catalyst having high catalytic activity can be realized, the efficiency of reduction reactions currently used in various fields can be improved. For example, it can be used for carbon dioxide reduction reaction.

  Further, in a binder for a fuel cell, a resin containing a halogen is often used, and a resin that does not contain a halogen and that can achieve the performance of the binder has been demanded.

  In addition, high proton conductivity, electrical conductivity, and oxygen permeability are considered important for binders for fuel cells. At present, Nafion, which is widely used as a binder for fuel cells, is an insulator. Therefore, if a catalyst encased in Nafion and isolated from the electrode is generated, the catalyst utilization rate is reduced. It is considered that such a problem can be solved if there is a binder imparted with electrical conductivity in addition to proton conductivity.

JP 2004-335459 A JP 2013-202430 A

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

  However, although the above Patent Document 2 and Non-Patent Document 1 do not use expensive platinum as a catalyst, synthesis under a severe condition or synthesis for a long time using a strong acid is necessary for the synthesis of the catalyst. Therefore, the present invention provides an oxygen reduction reaction active catalyst having high catalytic activity capable of being easily synthesized without using an expensive catalyst 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 completed the present invention. .

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

(Claim 1)
A catalyst for promoting a reduction reaction,
The following general formula (1):
− (A ¹ ) _k − (1)
Wherein the polyaniline or a fired body thereof is represented by:
Each A ¹ is independently a substituted or unsubstituted aniline monomer residue;
A ¹ each independently has m phosphonic acid residues R ^p and n substituents R;
Phosphonic acid residue R ^p is represented by the following formula:

Where
M ¹ and M ² are each independently a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, an aralkyl group having 7 to 34 carbon atoms, an aryl group having 6 to 30 carbon atoms, an alkali metal, an alkaline earth metal, 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,
When ^{one of} M ¹ or M ² is an alkaline earth metal, the alkaline earth metal atom is bonded to two O ⁻ in one R ^p group, and M ¹ or M ² Or a structure in which the alkaline earth metal atom cross-links O ⁻ of two R ^p groups,
R each independently represents a 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, an alkylthio group having 1 to 15 carbon atoms, 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 an ester residue, a nitro group, and a cyano group;
m is each independently an integer of 1 to 4,
n is each independently an integer of 0 to 3,
In each aniline monomer residue, the sum of m and n is independently 4 or less,
k is an integer of 4 to 3000,
catalyst.

(Section 2)
Item 4. The catalyst according to Item 1, further comprising a bipyridine compound.

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

(Section 4)
Item 4. The catalyst according to any one of Items 1 to 3, comprising a calcined body of the polyaniline.

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

(Claim 6)
Item 6. The catalyst according to any one of Items 1 to 5, which promotes an oxygen reduction reaction.

(Claim 7)
Item 7. The catalyst according to any one of Items 1 to 6, which promotes an oxygen reduction reaction in a positive electrode of a fuel cell.

(Section 8)
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 based on the number of aniline monomer residues.

(Claim 9)
9. A fuel cell comprising the catalyst according to any one of items 1 to 8 as a positive electrode.

(Section 10)
The following general formula (1):
− (A ¹ ) _k − (1)
A solid polymer fuel cell binder containing polyaniline represented by the formula:
Each A ¹ is independently a substituted or unsubstituted aniline monomer residue;
A ¹ each independently has m phosphonic acid residues R ^p and n substituents R;
Phosphonic acid residue R ^p is represented by the following formula:

Where
M ¹ and M ² are each independently a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, an aralkyl group having 7 to 34 carbon atoms, an aryl group having 6 to 30 carbon atoms, an alkali metal, an alkaline earth metal, 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,
Provided that at least one M ^{1 in the} polyaniline is a hydrogen atom;
When ^{one of} M ¹ or M ² is an alkaline earth metal, the alkaline earth metal atom is bonded to two O ⁻ in one R ^p group, and M ¹ or M ² Or a structure in which the alkaline earth metal atom cross-links O ⁻ of two R ^p groups,
R each independently represents a 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, an alkylthio group having 1 to 15 carbon atoms, 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 an ester residue, a nitro group, and a cyano group;
m is each independently an integer of 1 to 4,
n is each independently an integer of 0 to 3,
In each aniline monomer residue, the sum of m and n is independently 4 or less,
k is an integer of 4 to 3000,
A binder for polymer electrolyte fuel cells.

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

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

(Section 13)
A method for producing the catalyst according to any one of items 1 to 8,
The following general formula (2):
− (A ² ) _k − (2)
Including a step of obtaining a phosphorus-containing polyaniline by conducting a phosphonation reaction on the polyaniline compound represented by the formula, and a step of forming a catalyst from the phosphorus-containing polyaniline, wherein
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 defined in item 1 above.
Method.

(Item 14)
A method for producing the binder according to Item 10 or 11,
The following general formula (2):
− (A ² ) _k − (2)
A step of obtaining a phosphorus-containing polyaniline by conducting a phosphonation reaction on the polyaniline compound represented by the formula: and a step of forming a binder from the phosphorus-containing polyaniline, wherein
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 defined in item 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 a catalytic activity ability easily and inexpensively without using a conventional catalyst such as platinum.

  According to the present invention, there is no need for steps such as recrystallization, and a simple manufacturing method, for example, a manufacturing method consisting of only a baking step, or a manufacturing method consisting of a step of mixing and baking a metal or bipyridyl solution. Catalysts that can be produced are provided.

  Moreover, according to this invention, it can be set as the binder which does not contain a halogen by using the binder containing polyaniline phosphonic acid. In addition to proton conductivity, this binder has electrical conductivity, and can prevent a phenomenon that a catalyst isolated from the electrode by being encased in the binder is generated, resulting in a decrease in catalyst utilization.

FIG. 1 shows measurement results of oxygen reduction activity of platinum-supported carbon using PMAP / pyridine as a binder in Example 1 and measurement results of oxygen reduction activity of platinum-supported carbon using Nafion as a binder in Comparative Example 1. FIG. 2 shows measurement results of oxygen reduction activity of the PMAP fired bodies (PMAP700, PMAP800, PMAP900) synthesized in Example 2. FIG. 3 shows the measurement results of the oxygen reduction activity of the PMAP / 4,4′-bipyridyl fired body synthesized in Example 3 (PMAP / bpy / DMF / 900). FIG. 4 shows the measurement results of the oxygen reduction activity of the PANI fired body synthesized in Comparative Example 2 (PANI / H ₂ O / 900). 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 on the fired body obtained by acid immersion / re-fired treatment of the PMAP / FeCl ₃ fired body synthesized in Example 7.

  Hereinafter, the present invention will be described in detail.

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

  In the present specification, the “fuel cell” means a polymer electrolyte fuel cell (PEFC). In order to improve the output of PEFC, the three-phase interface of the electrolyte membrane, the electrode catalyst, and the fuel (negative electrode active material) in the negative electrode, and the electrolyte membrane, the electrode catalyst, and oxygen (positive electrode active material) in the positive electrode. It is necessary to increase the area of the phase interface and to perform an efficient chemical reaction.

  In response to such a requirement, since the polyaniline used in the present invention contains a phosphorus-containing functional group and has an aniline skeleton, the bond distance due to the functional group is increased compared to graphite used as a conventional electrode catalyst. It is considered that the surface area is increased, and 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 the formula (2) are cross-linked is formed, the surface area is further increased, and the efficiency of oxygen supply is increased, thereby exhibiting excellent catalytic activity.

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

  A fuel cell using a catalyst and a binder 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)
Where polyaniline represented by:
Each A ¹ is independently a substituted or unsubstituted aniline monomer residue;
A ¹ each independently has m phosphonic acid residues R ^p and n substituents R.

Phosphonic acid residue R ^p is expressed by the following equation.

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

M ¹ and M ² in the phosphonic acid residue are preferably selected from a hydrogen atom, an alkali metal and an alkaline earth metal. 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, it is not always necessary for polyaniline to have high conductivity, and therefore it is not always necessary that hydrogen be present in the phosphonic acid residue. When polyaniline is used for the binder, it is necessary that the polyaniline has high conductivity, and therefore it is preferable that the phosphonic acid residue has a large amount of hydrogen.

  As used herein, “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 and cesium.

  As used herein, “alkaline earth metal” refers to any atom belonging to Group 2 of the Periodic Table. Specific examples of the alkaline earth metal include beryllium, magnesium, calcium, strontium, barium and radium.

  The substituent R is at least one selected from the group consisting of halogen atoms, alkyl groups, aralkyl groups, alkoxy groups, alkylthio groups, alkylamino groups, carboxyl groups, carboxylic acid alkyl ester groups, nitro groups, and cyano groups. is there. Among these, an electron donating group such as an alkyl group, an alkoxy group, an alkylthio group, and an alkylamino group is preferable, and an alkyl group and an alkoxy group 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 the present specification, “alkyl” refers to a monovalent group generated by losing 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). A chain alkyl may be a straight chain or branched chain. The cyclic alkyl may be composed only of a cyclic structure, or may be a structure in which a chain alkyl is further bonded to the cyclic structure. The carbon number of the alkyl can be any natural number. The carbon number of alkyl is 1-30 in one embodiment and 1-20 in another embodiment. In yet another embodiment, it is 1-10, and in yet another embodiment, 1-5.

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

  In the present specification, the “aralkyl group” refers to a structure in which a part of hydrogen atoms of an alkyl group is substituted with an aryl group.

  In the present specification, the “aryl group” refers to a group formed by leaving one hydrogen atom bonded to an aromatic hydrocarbon ring. The number of aromatic hydrocarbon rings constituting the aryl group may be one, or two or more. Preferably, it is 1-3. When there are a plurality of rings of aromatic hydrocarbons in the molecule, 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 in the general formula (1) may be linear or branched, and preferably has 1 to 10 carbon atoms. Is more preferably 1-5. 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. Terphenyl (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, a carboxyl group, A cyano group, a nitro group, a sulfone group, etc. are mentioned.

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

In this specification, “alkoxy” refers to a group in which an oxygen atom is bonded to the alkyl group. That is, when the alkyl group is represented as R ^A —, it refers to a group represented by R ^A O—. A chain alkoxy can be straight or branched. The cyclic alkoxy may be composed of only a cyclic structure, or may be a structure in which a chain alkyl is further bonded to the cyclic structure. The number of carbon atoms of 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 preferably has 1 to 15 carbon atoms, and preferably has 1 to 8 carbon atoms. More preferably, it is particularly preferably 1-4. Specific examples include methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, tridecyl Examples thereof include an oxy group, a tetradecyloxy group, and a pentadecyloxy group.

As used herein, “alkylthio” refers to a group in which a sulfur atom is bonded to the alkyl group. That is, when the alkyl group is represented as R ^A —, it refers to a group represented by R ^A S—. A chain alkylthio may be linear or branched. The cyclic alkylthio may be composed only of a cyclic structure, or may be a structure in which a chain alkyl is further bonded to the cyclic structure. The carbon number of 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 preferably has 1 to 15 carbon atoms, and preferably 1 to 8 carbon atoms. Is more preferable, and 1 to 4 is particularly preferable. Specific examples include methylthio, ethylthio, propylthio, butylthio, pentylthio, hexylthio, heptylthio, octylthio, nonylthio, decylthio, undecylthio, dodecylthio, tridecylthio, tetradecylthio, and penta Examples include decylthio group.

As used herein, “alkylamino” refers to a group in which an amino group is bonded to the alkyl group. That is, when the alkyl group is represented as R ^A —, it refers to a group represented by R ^A NH—. A chain alkylamino may be linear or branched. The cyclic alkylamino may be composed of only a cyclic structure, or may be a structure in which a chain alkyl is further bonded to the cyclic structure. The carbon number of 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 preferably has 1 to 15 carbon atoms, and preferably 1 to 8 carbon atoms. It is further more preferable and it is especially preferable that it is 1-4. 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, dodecylamino group. Group, tridecylamino group, tetradecylamino group, pentadecylamino group and the like.

In the present specification, the “carboxylic acid alkyl ester” refers to a group in which a carboxylic acid group is bonded to the alkyl group. That is, when the alkyl group is represented as R ^A —, it refers to a group represented by —COOR ^A. The chain carboxylic acid alkyl ester may be linear or branched. The cyclic carboxylic acid alkyl ester may be composed only of 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 a benzene ring is described as Ph, a structure of Ph—C (═O) —OR ^A is obtained. As this carboxylic acid alkyl ester group, the alkyl group preferably has 1 to 15 carbon atoms, more preferably 1 to 8, and particularly preferably 1 to 4. Specific examples include methyl carboxylate, ethyl carboxylate, propyl carboxylate, butyl carboxylate, pentyl carboxylate, hexyl carboxylate, heptyl carboxylate, octyl carboxylate, nonyl carboxylate, Examples thereof include a carboxylic acid decyl group, a carboxylic acid undecyl group, a carboxylic acid dodecyl group, a carboxylic acid tridecyl group, a carboxylic acid tetradecyl group, and a carboxylic acid pentadecyl group.

  The number m of the phosphonic acid residues of 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, more preferably 1 to 4. It is an integer of 2. The number n of substituents R is an integer of 0-3, preferably an integer of 0-2, more preferably an integer of 0-1. 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 the para position. That is, when the second aniline monomer residue is bonded to the first aniline monomer residue and the third aniline monomer residue is bonded to the second aniline monomer residue, the first aniline monomer residue is The group and the third aniline monomer residue are para to each other in the benzene ring in the second aniline monomer residue.

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

  However, it is known that the skeleton structure of polyaniline is not limited to the structure represented by the general formula (1a). Therefore, the skeleton 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 a phenylenediamine skeleton of a reduced unit of the following general formula (1b) and

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

  Therefore, the aniline residue in the polyaniline in this specification may have a skeleton structure as shown in the general formula (1b) or (1c).

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

It may have a structure having a repeating unit of

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

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

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

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

Wherein R is as defined above, and M ^1c and M ^2c are each independently a group consisting of an alkyl group, an aralkyl group, an aryl group, an alkali metal, an alkaline earth metal, an ammonium group, and a pyridinium group. M ³ is an integer of 0 to 4, and n ³ is an integer of 0 to 4. However, the sum of m ³ and n ³ is 4 or less.)
The repeating unit represented by these can be included.

  In addition, when describing the structure of polyaniline in a general formula, it is common to omit both ends, so in this specification as a general rule, both ends are omitted when describing the structure of polyaniline. . However, for example, if both terminal groups are described in the 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 each a terminal group. Usually, one is a polymerization initiation terminal and the other is a polymerization termination terminal.

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

[H- (A ¹ ) _k -H] (1 g)
On the other hand, for example, International Publication WO2014 / 167818 describes that an aniline oligomer having a phenazine ring structure is formed in the initial stage of aniline polymerization, and the oligomer residue serves as a polymerization initiation side terminal of the polymer. However, even when a structure different from the structure of the monomer residue in the repeating unit is present at the terminal, the type of the terminal group of the polyaniline has little influence 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. A copolymer is preferred. The copolymer may be a block copolymer or a random copolymer. In a random copolymer, a plurality of types of monomer residues are arranged randomly. As described in the above-mentioned International Publication WO2014 / 167818 and the like, it is known that polyaniline obtained by oxidative polymerization of an aniline monomer has a structure having a certain regular repeating unit. Also in the production method of the present invention, it is considered that polyaniline having such regularity can be produced, and polyaniline having such regularity is used as a target polymer of the production method of the present invention. Can do.

The polyaniline is a group consisting of at least a phosphonic acid group (—PO ₃ H ₂ ) or a phosphonic acid monohydrogen base (—PO ₃ HM ⁸ , where M ⁸ is an alkali metal, an alkaline earth metal, an ammonium group, and a pyridinium group. Phosphonic acid groups or phosphonic acid monohydrogen bases can be doped with nitrogen on the polyaniline main chain by means of their hydrogen atoms.

  In the present specification, the phosphonic acid monohydrogen base means a group having a structure of phosphonic acid monohydrogen salt. That is, it refers to a group in which only one of two hydrogens of a phosphonic acid group 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 properties.

  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 physical properties required for the catalyst or the binder. When 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 % Or more, 90% or more, or 95% or more. In addition, when it is preferable to suppress the introduction rate to be low, for example, the introduction rate can be adjusted to 95% or less, 90% or less, 85% or less, 75% or less, or 70% or less. It is.

  If the amount of the phosphonic acid residue introduced into the polyaniline compound is increased, the effect of introducing the phosphonic acid residue can be enhanced. For example, the conductivity imparting effect can be increased. 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 phosphonating agent, and the like. Moreover, you may adjust the quantity which introduce | transduces a phosphonic acid residue into a polyaniline compound by adjusting reaction conditions, for example, reaction temperature and 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.

  Moreover, you may manufacture the polyaniline used for this invention by the method different from a conventionally well-known method.

[New production method of phosphorus-containing polyaniline]
In the production method of the present invention, phosphorus-containing polyaniline is produced by phosphonation of a polyaniline compound or a polyaniline mixture containing a polyaniline compound.

(Polyaniline compound)
In the present specification, “polyaniline compound” in relation to a novel method for producing phosphorus-containing polyaniline means polyaniline capable of performing a phosphonation reaction to obtain phosphorus-containing polyaniline. Specifically, it is unsubstituted polyaniline or substituted polyaniline. Substituted polyaniline refers to those having a substituent on at least one of the nitrogen of the benzene ring and amino group residue. In the benzene ring, the amino group residue nitrogen is the 1-position, and there are substituents at one to four of the 2-position, 3-position, 5-position and 6-position (ie, ortho-position or meta-position). be able to.

  In the present specification, the “polyaniline mixture” refers to a mixture in which two or more kinds of polyaniline compounds are mixed.

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

In this specification, “aniline monomer” or “aniline monomer compound” means a monomer capable of performing a polymerization reaction to obtain polyaniline from aniline. Specifically, it is unsubstituted aniline (C ₆ H ₅ NH ₂ ), substituted aniline or a salt thereof. Substituted aniline refers to one having a substituent on at least one of its benzene ring and amino group. In the benzene ring, a substituent can be present in one to four of the 2-position, 3-position, 5-position and 6-position (that is, ortho-position or meta-position) with the amino group as the 1-position. However, since a 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. The salt of unsubstituted or substituted aniline is a salt in which the amino group is converted into a salt, and the salt does not interfere with the polymerization reaction. Examples of unsubstituted or substituted aniline salts include ammonium salts.

  In the present specification, the “aniline monomer mixture” refers to a mixture in which two or more aniline monomer compounds are mixed.

  The polyaniline compound used as a raw material in the production method of the present invention comprises the amino group residue nitrogen at the 1st position, the 1st position (nitrogen) of one aniline monomer residue, and the 4th position of another aniline monomer residue. Has a bonded 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 is bonded to the 4-position of another aniline monomer residue. The resulting phosphorus-containing polyaniline (conductive polyaniline and phosphorus-containing polyaniline ester) is in the 2-position, 3-position, 5-position, and 6-position (ie, ortho-position or meta-position) with the nitrogen of the amino group residue as the first position. It becomes a structure in which a substituent can exist in one to four of them.

  In this specification, “phosphorus-containing polyaniline” refers to polyaniline having a phosphonic acid residue.

  In this specification, “phosphorus-containing polyaniline ester” refers to phosphorus-containing polyaniline having a phosphonic acid residue which is an alkyl ester or an aralkyl ester.

  As used herein, “residue” refers to a group that remains after a reaction material reacts. The amino group residue means a portion remaining in a polymer produced by elimination of hydrogen from the amino group of aniline when aniline is polymerized. In addition, for example, an unsubstituted aniline monomer residue means a portion remaining in a polymer formed by one unsubstituted aniline monomer molecule when aniline is polymerized, that is, one benzene ring and one nitrogen atom and hydrogen. The part which becomes. The substituted aniline monomer residue refers to a hydrogen or substituent further comprising, as a skeleton, a portion remaining in a polymer formed by one substituted aniline monomer molecule when aniline is polymerized, that is, one benzene ring and one nitrogen atom. The part containing In the present 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 polymer that is a raw material when phosphonation is performed.

− (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 halogen atoms, alkyl groups, aralkyl groups, alkoxy groups, alkylthio groups, alkylamino groups, carboxyl groups, carboxylic acid alkyl ester groups, nitro groups, and cyano groups. Of these, electron donating groups such as a halogen atom, an alkyl group, an alkoxy group, an alkylthio group, and an alkylamino group are preferable, and an alkyl group and an alkoxy group 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 the present specification, “alkyl” refers to a monovalent group generated by losing 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). A chain alkyl may be a straight chain or branched chain. The cyclic alkyl may be composed only of a cyclic structure, or may be a structure in which a chain alkyl is further bonded to the cyclic structure. The carbon number of the alkyl can be any natural number. The carbon number of alkyl is 1-30 in one embodiment and 1-20 in another embodiment. In yet another embodiment, it is 1-10, and in yet another embodiment, 1-5.

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

  In the present specification, the “aralkyl group” refers to a structure in which a part of hydrogen atoms of an alkyl group is substituted with an aryl group.

  In the present specification, the “aryl group” refers to a group formed by leaving one hydrogen atom bonded to an aromatic hydrocarbon ring. The number of aromatic hydrocarbon rings constituting the aryl group may be one, or two or more. Preferably, it is 1-3. When there are a plurality of rings of aromatic hydrocarbons in the molecule, 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 still 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, More preferably, it has 1 to 5 carbon atoms. 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. Terphenyl (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, a carboxyl group, A cyano group, a nitro group, a sulfone group, etc. are mentioned.

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

In this specification, “alkoxy” refers to a group in which an oxygen atom is bonded to the alkyl group. That is, when the alkyl group is represented as R ^A —, it refers to a group represented by R ^A O—. A chain alkoxy can be straight or branched. The cyclic alkoxy may be composed of only a cyclic structure, or may be a structure in which a chain alkyl is further bonded to the cyclic structure. The number of carbon atoms of 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 general formula (2), the alkyl group portion may be linear or branched, and has 1 to 15 carbon atoms. Preferably, it is 1-8, and it is especially preferable that it is 1-4. Specific examples include methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, tridecyl Examples thereof include an oxy group, a tetradecyloxy group, and a pentadecyloxy group.

As used herein, “alkylthio” refers to a group in which a sulfur atom is bonded to the alkyl group. That is, when the alkyl group is represented as R ^A —, it refers to a group represented by R ^A S—. A chain alkylthio may be linear or branched. The cyclic alkylthio may be composed only of a cyclic structure, or may be a structure in which a chain alkyl is further bonded to the cyclic structure. The carbon number of 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 preferably has 1 to 15 carbon atoms, It is more preferable that it is 1-8, and it is especially preferable that it is 1-4. Specific examples include methylthio, ethylthio, propylthio, butylthio, pentylthio, hexylthio, heptylthio, octylthio, nonylthio, decylthio, undecylthio, dodecylthio, tridecylthio, tetradecylthio, and penta Examples include decylthio group.

As used herein, “alkylamino” refers to a group in which an amino group is bonded to the alkyl group. That is, when the alkyl group is represented as R ^A —, it refers to a group represented by R ^A NH—. A chain alkylamino may be linear or branched. The cyclic alkylamino may be composed of only a cyclic structure, or may be a structure in which a chain alkyl is further bonded to the cyclic structure. The carbon number of 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 preferably has 1 to 15 carbon atoms. 1 to 8 is more preferable, and 1 to 4 is particularly preferable. 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, dodecylamino group. Group, tridecylamino group, tetradecylamino group, pentadecylamino group and the like.

In the present specification, the “carboxylic acid alkyl ester” refers to a group in which a carboxylic acid group is bonded to the alkyl group. That is, when the alkyl group is represented as R ^A —, it refers to a group represented by —COOR ^A. The chain carboxylic acid alkyl ester may be linear or branched. The cyclic carboxylic acid alkyl ester may be composed only of 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 a benzene ring is described as Ph, a structure of Ph—C (═O) —OR ^A is obtained. As this carboxylic acid alkyl ester group, the alkyl group preferably has 1 to 15 carbon atoms, more preferably 1 to 8, and particularly preferably 1 to 4. Specific examples include methyl carboxylate, ethyl carboxylate, propyl carboxylate, butyl carboxylate, pentyl carboxylate, hexyl carboxylate, heptyl carboxylate, octyl carboxylate, nonyl carboxylate, Examples thereof include a carboxylic acid decyl group, a carboxylic acid undecyl group, a carboxylic acid dodecyl group, a carboxylic acid tridecyl group, a carboxylic acid tetradecyl group, and a carboxylic acid pentadecyl group.

  In the 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, 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, “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 and cesium.

  As used herein, “alkaline earth metal” refers to any atom belonging to Group 2 of the Periodic Table. Specific examples of the alkaline earth metal 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 exists in the substituent of polyaniline, the Hirao reaction described later can be performed. When polyaniline having halogen as the substituent R is used, the number of aniline monomer residues in which halogen is present as the 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%, where the number of aniline monomer residues present in polyaniline is 100%. % Or more, 60% or more, 70% or more, 80% or more, 90% or more, or 95% or more. Alternatively, it may be 100%. In addition, when 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 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, the above-described substituted or unsubstituted polyaniline compound is preferably used as a polymer for phosphonation. However, if necessary, a polymer capable of being phosphonated (hereinafter referred to as “other polymer”) other than the substituted or unsubstituted polyaniline compound is added to the polymer mixture as a raw material in the production of phosphorus-containing polyaniline. It may be contained in a small amount that does not interfere with the effect. That is, a substituted or unsubstituted polyaniline compound having no phosphonic acid may be copolymerized as 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 other than phosphonic acid (for example, sulfonic acid). Alternatively, 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 advantage of the present invention is impaired. Therefore, it is preferable that the amount of the other type polymer used is not too large. The amount of the other polymer used is preferably 40 mol% or less, more preferably 30 mol% or less, and more preferably 20 mol% or less of the total amount of the substituted or unsubstituted polyaniline compounds used in the polymerization. More preferably, 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]
A phosphorus-containing polyaniline is obtained by reacting a polyaniline compound or a polyaniline mixture with phosphite to perform phosphonation. As the phosphonation method, any phosphonation method capable of introducing a phosphonic acid residue into the polyaniline compound can be employed. As the phosphite, any phosphite capable of reacting with a polyaniline compound or a polyaniline mixture can be used.

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

  General formula (3):

(Here, M ^{3 to} M ⁵ may be the same or different, and are each independently an alkyl group having 1 to 15 carbon atoms, an aralkyl group having 7 to 34 carbon atoms, or 6 to 6 carbon atoms. 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 Is a structure in which the alkaline earth metal atom is bonded to two O ⁻ and one of the remaining two of M ^{3 to} M ⁵ does not exist.)
General formula (4):

(Here, M ⁶ and M ⁷ may be the same, each independently an alkyl group having 1 to 15 carbon atoms, an aralkyl group having 7 to 34 carbon atoms, an aryl group having 6 to 30 carbon atoms, Selected from the group consisting of a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, and a pyridinium group, provided that when one of M ⁶ and M ⁷ is an alkaline earth metal, two O ^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 tautomeric relationship with the general formula (4) and is the same compound. In the present specification, the compound will be described as a compound of the general formula (4).

  In the present specification, “phosphonation” means a reaction in which a polyaniline compound or a polyaniline mixture is reacted with a phosphite to synthesize a phosphorus-containing polyaniline. In the present specification, the “phosphonating agent” means an oxidant or a catalyst used for the Hirao reaction. In the present specification, “oxidation” means that a hydrogen atom is extracted from a polyaniline compound or a polyaniline mixture using an oxidizing agent. As used herein, “oxidizing agent” refers to a reagent that causes such an oxidation reaction.

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

(Other phosphonation reactions)
In the phosphonation reaction of the present invention, the above-mentioned “nucleophilic synthesis” is carried out by synthesizing a phosphorus-containing polyaniline by reaction with a 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 the “phosphonation reaction by addition”. However, if necessary, a method called phosphonation by the Hirao reaction may be adopted.

  In the present specification, “phosphonation by Hirao reaction” means a reaction for synthesizing a phosphorus-containing polyaniline by coupling a polyaniline compound or a polyaniline mixture with a dialkyl phosphite represented by the general formula (4). In the present specification, the “Hirao reaction” refers to a reaction in which a phosphite is bonded 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, more preferably Pd (PPh ₃ ) ₄ or Pd (OAc) ₂ . Further, if necessary, phosphonation by the Hirao reaction is preferably heated in a vacuum (hereinafter referred to as flame dry) before the reaction is charged in order to prevent catalyst deactivation. The Hirao reaction is specifically described in International Publication WO2014 / 167818.

(Amount of phosphite)
The amount of phosphite used in the method of the present invention is not particularly limited. The design can be appropriately performed in consideration of the type of polyaniline compound and the type of phosphite to be introduced into the polyaniline compound. For example, if the polyaniline compound is an unsubstituted aniline, phosphonic acid residues can be introduced at four positions on the benzene ring, so 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. When a large number of phosphonic acid residues are to be introduced, a large amount of phosphite may be used, and when 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. 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 the phosphite to the polyaniline compound is a calculated value of the total number of places where phosphonic acid residues present in the polyaniline compound can be introduced (for example, the number of aniline monomer residues in the case of unsubstituted polyaniline). 4 times) in moles of phosphite.

(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 designed appropriately in consideration of the type of polyaniline compound and the type and amount of phosphonic acid residue to be introduced into the polyaniline compound. For example, if the polyaniline compound is an unsubstituted aniline, phosphonic acid residues can be introduced at four positions on the benzene ring, so 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 a large number of phosphonic acid residues are to be introduced, a large amount of phosphonating agent may be used. When a small number of phosphonic acid residues are to be introduced, 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 phosphonating 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. For example, the amount of the phosphonating 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 the calculated value of the total number of places where phosphonic acid residues present in the polyaniline compound can be introduced (for example, the number of aniline monomer residues in the case of unsubstituted polyaniline). 4 times the number of moles of phosphonating agent.

(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 physical properties required for the target phosphorus-containing polyaniline. Assuming that the number of aniline monomer residues present in the 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. Alternatively, it may be 100%. If high conductivity is desired, it can be designed to introduce more phosphonic acid residues. Moreover, when it is desired to control the phosphonation rate for some reason, it can be designed so that the number of phosphonic acid residues introduced is suppressed. In such a case, for example, the introduction rate can be adjusted to 95% or less, 90% or less, 85% or less, or 80% or less.

  If the amount of the phosphonic acid residue introduced into the polyaniline compound is increased, the effect of introducing the phosphonic acid residue can be enhanced. For example, the conductivity imparting effect can be increased. 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 phosphite or the amount of the phosphonating agent. Moreover, you may adjust the quantity which introduce | transduces a phosphonic acid residue into a polyaniline compound by adjusting reaction conditions, for example, reaction temperature and reaction time.

(Oxidant)
In the present invention, when an oxidizing agent is used for the phosphonation reaction, hydrogen atoms are removed from the polyaniline compound. That is, the polyaniline compound having an oxidation state of emeraldine base is converted into a pernigraniline salt or a base. Therefore, the phosphonation reaction is performed in the presence of an oxidizing agent for causing this dehydrogenation. As the oxidizing agent, an oxidizing agent generally used in phosphonation can be used. Specific examples include ammonium peroxodisulfate, sodium peroxosulfate, 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 oxidation can proceed. It is preferably 0.5 equivalents or more, more preferably 0.7 equivalents or more, still more preferably 1.0 equivalents or more, and 1.5 equivalents relative to the total amount of polyaniline compound to be phosphonated. The above is most preferable. And it is also possible to set it as 2.1 equivalent or more, 2.2 equivalent or more, 2.4 equivalent or more, 2.6 equivalent or more, 2.8 equivalent or more, or 3.0 equivalent or more as needed. Further, it is preferably 10 equivalents or less, more preferably 8 equivalents or less, still more preferably 6 equivalents or less, particularly preferably 5 equivalents or less, relative to the polyaniline compound to be phosphonated, Most preferably, it is 4 equivalents or less. And 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 set it to 3.1 equivalents or less.

  Here, the equivalent of the oxidizing agent to the polyaniline compound is the calculated value of the total number of places where phosphonic acid residues present in the polyaniline compound can be introduced (for example, the number of aniline monomer residues in the case of unsubstituted polyaniline). Calculated as moles of oxidant to (4 times). For example, if 1 mol of a compound such as persulfate is an oxidizing agent that can extract 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 performed 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)
You may perform reaction of the phosphonation of this invention using a solvent as needed. 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. Preferably, it is 20 ° C. or higher, more preferably 30 ° C. or higher, and further 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 further preferably 120 ° C. or lower. If the reaction temperature is within the preferred range, the phosphorus-containing polyaniline ester can be obtained in high yield.

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

  The reaction time is preferably 1 hour or more, more preferably 3 hours or more, further preferably 6 hours or more, still more preferably 9 hours or more, and particularly preferably 12 hours or more. Yes, it may be 15 hours or longer, 18 hours or longer, 21 hours or longer, or 24 hours or longer as required. Further, it is preferably 7 days or less, more preferably 5 days or less, still more preferably 3 days or less, still more preferably 2 days or less, 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 phosphonation 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 performed. By performing hydrolysis, for example, polyaniline having proton conductivity and conductivity can be obtained.

  As a method for hydrolysis, any known method can be employed as a method for hydrolyzing a phosphonate. For example, the hydrolysis can be performed by a method of treating with a strong acid or a method of treating with a strong alkali. Examples of strong acids 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. Here, when a Lewis acid is used, for example, a method of reacting with Lewis acid and then reacting with water can be preferably used.

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

  For example, the reaction temperature during hydrolysis is 20 ° C. or higher, more preferably 30 ° C. or higher, and further 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 further preferably 120 ° C. or lower. If the reaction temperature is within the preferred range, the phosphorus-containing polyaniline ester can be obtained in high yield.

  For example, the reaction time of hydrolysis is preferably 1 hour or longer, more preferably 2 hours or longer, and further preferably 3 hours or longer. Moreover, it is preferably 2 days or less, more preferably 1 day or less, still more 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.

  In the present specification, “phosphorus-containing polyaniline” refers to one obtained by phosphonation of 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 part, or may be a phosphorus-containing polyaniline ester having an ester bond at the phosphonic acid residue part. A compound in which a phosphonate is bonded to a polyaniline compound as a substituent is referred to as a polyaniline ester in the present specification. The phosphorus-containing polyaniline ester is particularly useful as an intermediate for producing conductive polyaniline.

  The degree of polymerization of polyaniline can be arbitrarily set, for example, can be 4 or more, 6 or more, or 8 or more, and is 3,000 or less, 2,000 or less, or 1,200 or less. Is possible. Or it is possible to set it as the polymerization degree described about k of following General formula (1).

  Similarly, the molecular weight of polyaniline can be set arbitrarily. For example, it is possible to set it as the molecular weight corresponding to the polymerization degree described about k of the following general formula (1).

  The number average molecular weight of the 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. Is possible.

  According to the method for producing phosphorus-containing polyaniline of the present invention, phosphorus-containing polyaniline having a high degree of polymerization can be easily obtained. 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 performing the phosphonation 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, for example, by the general formula (1):
− (A ¹ ) _k − (1)
Here, A ¹ is each independently an aniline monomer residue. k is the degree of polymerization and is an arbitrary 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. In addition, about the number average molecular weight and a weight average molecular weight, the description mentioned above regarding the polyaniline in this specification is applicable also to the polyaniline of General formula (1).

  Adjacent aniline monomer residues are linked at the para position. That is, when the second aniline monomer residue is bonded to the first aniline monomer residue and the third aniline monomer residue is bonded to the second aniline monomer residue, the first aniline monomer residue is The group and the third aniline monomer residue are para to each other in the benzene ring in the second aniline monomer residue.

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

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

  In the conductive polyaniline having self-doping property, it is necessary that hydrogen exists in the phosphonic acid residue. The number of phosphone residues in which hydrogen exists 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 the phosphorus-containing polyaniline is 100%. , 60% or more, 70% or more, 80% or more, 90% or more, or 95% or more. Alternatively, it may be 100%. In addition, when it is desired to control the hydrogen content for any reason, it can be designed so that the number of phosphonic acid residues in which hydrogen is present is suppressed. 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, Or it is possible to design to 70% or less.

  Moreover, the ratio of the phosphonic acid residue in which hydrogen exists with respect to the total number of phosphonic acid residues can also be designed arbitrarily. The number of phosphonic acid residues present in the phosphorus-containing polyaniline is 100%, and 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 60% or more, 70% or more, 80% or more, 90% or more, or 95% or more. Alternatively, it may be 100%. In addition, when it is desired to control the hydrogen content for any reason, it can be designed so that the number of phosphonic acid residues in which hydrogen is present is suppressed. In such a case, the number of phosphonic acid 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, Or it is possible to design to 70% or less.

(Ion exchange)
In conducting polyaniline, the reaction material may be adjusted so that a desired amount of phosphonic acid residues in which hydrogen is present is introduced during phosphonation. For example, the type and amount of phosphite compound can be selected such that the desired amount of phosphonic acid residues present in the desired amount of hydrogen are introduced.

  In addition, the polyaniline obtained by the method of the present invention may be ion-exchanged to adjust the dope amount as necessary. Ion exchange can be performed with an acidic aqueous solution or an ion exchange resin.

  That is, when the amount of hydrogen of the obtained polyaniline phosphonic acid or phosphonic acid monohydrogen salt is less than the desired amount as a whole polymer, metal ions, pyridinium ions, and ammonium ions bonded to phosphonic acid are converted into hydrogen ions. By performing ion exchange, the effect of dope can be increased.

  On the other hand, if the amount of hydrogen of the phosphonic acid or phosphonic acid monohydrogen salt of the polyaniline obtained by polymerization is more than the desired amount as the whole polymer, the hydrogen ion of the phosphonic acid or phosphonic acid monohydrogen salt is replaced with another hydrogen ion. By performing ion exchange with ions (for example, alkali metal ions, ammonium ions, pyridinium ions, etc.), the effect of doping can be reduced.

  Ion exchange can be performed after synthesizing polyaniline. It can also be performed simultaneously with 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, ion exchange can be performed simultaneously with purification by filtration if the column to be filtered is filled with an ion exchange resin.

  As the ion exchange method, conventionally known ion exchange methods can be used.

[Phosphorus-containing polyaniline ester]
In one embodiment of the present invention, the phosphorus-containing polyaniline is a phosphorus-containing polyaniline ester having an ester bond. The phosphorus-containing polyaniline ester is particularly useful as an intermediate for producing conductive polyaniline.

The phosphorus-containing polyaniline ester has one or two ester bonds in 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 general formula (1) is an alkyl group having 1 to 15 carbon atoms, 7 carbon atoms It is selected from ˜34 aralkyl groups or C 6-30 aryl groups 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. A structure in which both M ¹ and M ² are esters is referred to herein as a diester.

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

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

  In one embodiment where there are no diesters in all phosphonic acid residues in the phosphorus-containing polyaniline ester, i.e. all esters are monoesters, at least one phosphonic acid residue is other than ethyl ester. Ester.

In one preferred embodiment, the phosphorus-containing polyaniline ester is obtained by phosphonation of a polyaniline compound. For example, it can be obtained by reacting a polyaniline compound with phosphite. Specific examples of the phosphite to be reacted include the phosphite of the above general formula (3) or 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. 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, an aralkyl group having 7 to 34 carbon atoms, Alternatively, by using an aryl group having 6 to 30 carbon atoms, an ester can be introduced into the resulting phosphorus-containing polyaniline.

The phosphorus-containing polyaniline ester can also be represented by the general formula (1) described above:
− (A ¹ ) _k − (1)
Each A ¹ independently has m phosphonic acid residues R ^p and n substituents R;
Phosphonic acid residue R ^p is represented 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 phosphone 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%, where the number of aniline monomer residues present in the phosphorus-containing polyaniline ester is 100%. It is possible to select from 60% or more, 70% or more, 80% or more, 90% or more, or 95% or more. Alternatively, it may be 100%. In addition, when it is desired to control the ester content for some reason, it can be designed so that the number of phosphonic acid residues in which the ester 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.

  The phosphonic acid 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. Moreover, both the phosphonic acid residue of a monoester and the phosphonic acid residue of a diester may exist. The phosphorus-containing polyaniline ester in which both the phosphonic acid residue of the monoester and the phosphonic acid residue of the diester are present can be produced, for example, by using two or more types of phosphite compounds. The number of phosphonic acid residues of the monoester and the number of phosphonic acid residues of the diester in the phosphorus-containing polyaniline ester can be arbitrarily selected. For example, assuming that the total number of phosphonic acid residues of the monoester and the number of phosphonic acid residues of the diester 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. In addition, the number of monoesters can be selected 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)
If the above-mentioned phosphorus-containing polyaniline ester is hydrolyzed, the ester moiety is decomposed to obtain phosphorus-containing polyaniline containing no ester. The thus obtained phosphorus-containing polyaniline containing no ester is useful as a proton conductive and conductive polymer.

(fuel)
When the reaction gas is supplied to the fuel cell of the present invention, the following electrochemical reaction mainly occurs and DC power is generated.
Negative electrode: 2H ₂ → 4H ⁺ + 4e ⁻
Positive electrode: O ₂ + 4H ⁺ + 4e ⁻ → 2H ₂ O
In platinum, 4-electron reduction occurs almost 100%, but in other catalysts such as heteroatom-doped carbon catalysts, 2-electron reduction such as O ₂ + 2H ⁺ + 2e ⁻ → H ₂ O ₂ can occur simultaneously. Are known.

  An oxidation reaction that generates protons 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 employed in the present invention as a proton source necessary for the reduction reaction on the positive electrode side include hydrogen gas, methanol, ethanol, 1-propanol, dimethyl ether, ammonia, and the like, with hydrogen being preferred.

(binder)
In the present specification, the binder means a binder for forming a catalyst layer by binding a catalyst in a polymer electrolyte fuel cell. In the polymer electrolyte fuel cell, protons contact the catalyst through the binder. Conventional binders are mainly produced using a solid electrolyte.

  In the fuel cell using the catalyst of the present invention, a conventional binder having proton conductivity can be used. Examples of such binders include PTFE (Polytetrafluorethylene), PVDF (Polyvinylidenefluoride), Nafion-based polymers, PA (Polyamide) -based polymers, PI (Polyimide) -based polymers, PVA (Polyvinylcoleol) -based polymers, PA -Based polymers and polyazole-based polymers can be used, and these can be used alone or in combination of two or more.

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

  In the fuel cell of the present invention, a catalyst layer may be formed using the catalyst of the present invention and a conventional binder, or a catalyst layer may be formed using the conventional catalyst and the binder of the present invention. You may form a catalyst layer using a catalyst and the binder of this 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, as an oxygen reduction reaction of a polymer electrolyte fuel cell.

  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 production method)
The phosphorus-containing polyaniline is preferably calcined to obtain a catalyst as a phosphorus-containing polyaniline fired body. Moreover, it is preferable to manufacture a catalyst by performing the addition process of a piperidine compound, the addition process of a metal compound, the grinding | pulverization process, or an acid immersion process as needed.

(Bipyridine compound)
In this 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-bipi Gills, 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-terpyridine-4,4,4-tricarboxylate, 4,4,4-triethyl-2,2: 6,2-terpyridine, 4- (4-bromophenyl)- 2,2: 6,2-terpyridine, 5-thio Nyl-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, etc. Is mentioned.

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

  As the metal in the metal compound to be added, a known transition metal element 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 rhenium, iron, cobalt, Select at least one from 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 do.

  In the present invention, since it provides a reduction catalyst having catalytic activity ability at low cost and easily, among the above, titanium, zirconium, vanadium, hafnium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, rhenium, iron, Non-noble metal elements such as cobalt, nickel, and zinc are preferably used, 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 catalytic metal and the mixture is baked, the metal element coordinates with nitrogen, oxygen and phosphorus to form a complex. It is possible to create a reduction catalyst that is superior in characteristics. The metal compound to be used is not particularly limited, but a solid or liquid metal, metal halide, metal hypohalite, metal halide, metal perhalogenate, metal oxide, metal peroxide, metal nitrite Salts, metal nitrates, metal carbonates, metal peroxocarbonates, metal carboxylates, metal sulfites, metal sulfides, metal sulfates, metal persulfates, metal thiosulfates, metal hypophosphites, At least one of phosphoric acid metal salt, phosphoric acid metal salt, metal hydroxide, inorganic metal complex, organometallic complex, and metal organic compound can be selected. In the present specification, the solid or liquid metal, that is, a metal simple substance is also referred to as a metal compound.

  Of these, metal halides, hypohalous acid metal salts, halogen acid metal salts, perhalogenate metal salts, subhalogen acid metal salts, sublimation acid salts from the viewpoints of easy handling and dispersibility and solubility in water or organic solvents. Metal nitrate, metal nitrate, carbonate, carboxylate, metal sulfide, metal sulfite, metal sulfate, metal persulfate, metal thiosulfate, metal hypophosphite, metal phosphite Salts, metal phosphates, metal hydroxides, and organometallic complexes are preferred.

Specific examples of preferred metal compounds include the following:
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 hexacyanoferrate (II), potassium hexacyanoferrate (III), iron (II) oxalate, iron (III) oxalate, iron (II) phosphate, phosphorus Iron (III) acid, ferrocene, iron (II) oxide, 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 (II) chloride, nickel (II) bromide, nickel sulfide (II), nickel sulfate (II), nickel nitrate (II), nickel oxalate (II), nickel phosphate (II), nickelocene, nickel oxide ( II), nickel compounds such as nickel hydroxide (II), nickel acetate (II), nickel lactate (II), nickel (II) acetylacetonate;
Chromium (II) chloride, chromium (III) chloride, chromium (II) bromide, chromium (III) bromide, chromium (III) sulfide, chromium (III) sulfate, chromium (III) nitrate, chromium (III) oxalate , Chromium phosphate (III), chromium oxide (II), chromium oxide (III), chromium oxide (IV), chromium oxide (VI), chromium hydroxide (III), chromium acetate (II), chromium acetate (III) , Chromium compounds such as chromium (III) lactate;
Cobalt (II) chloride, cobalt (III) chloride, cobalt (II) bromide, cobalt (III) bromide, cobalt (II) sulfide, cobalt (II) sulfate, cobalt (III) sulfate, cobalt (II) nitrate, Cobalt nitrate (III), cobalt oxalate (II), cobalt phosphate (II), cobalt cene, cobalt oxide (II), cobalt oxide (III), tricobalt tetroxide, cobalt hydroxide (II), cobalt acetate ( II), cobalt compounds such as 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 compounds such as vanadium oxalate (IV), vanadium metallocene, vanadium oxide (V), vanadium acetate, vanadium citrate, vanadium (IV) acetylacetonate;
Manganese (II) chloride, 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 chloride (II), iron chloride (III), iron sulfate (II), iron sulfate (III), iron nitrate (II), iron nitrate (III), iron hydroxide (II), water Iron oxide (III), iron acetate (II), iron acetate (III), nickel chloride (II), nickel sulfate (II), nickel nitrate (II), nickel hydroxide (II), nickel acetate (II), chloride More preferred are cobalt (II), cobalt chloride (III), cobalt sulfate (II), cobalt sulfate (III), cobalt nitrate (II), cobalt nitrate (III), cobalt hydroxide (II), and cobalt acetate (II). , Iron (II) chloride, iron (III) chloride, iron (II) acetate, iron (III) acetate, nickel (II) chloride, nickel (II) acetate, cobalt (II) chloride, cobalt (III) chloride, Cobalt (II) is more preferable.

  The said metal compound may be used individually by 1 type, and may use 2 or more types together.

(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 with further enhanced catalytic activity.
Hereinafter, acid immersion refers to a process of performing treatment with an acid solution.

  Although it does not specifically limit about said processing method, Specifically, acid immersion can be performed by immersing phosphorus-containing polyaniline in an acid solution for a fixed time. It is not necessary to stir at the time of acid soaking. When stirring, it may be shaken lightly by hand, shaken strongly, a rotor may be used, or a stirring rod may be used. In addition, as an operation instead of stirring, an operation of heating and refluxing the acid solution, 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 from the melting point to the boiling point of the solution. In order to increase the catalytic activity, acid immersion may be performed at a high temperature, and even if acid immersion is performed at a low temperature, the catalytic activity can be increased. As long as it is within the above temperature range, acid immersion may be performed at a constant temperature, 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 for easy handling and to suppress decomposition of the 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, 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, Or 1 mol / L or less, or 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, preferably 5 mol / L or less, or 1 mol / L or less, or 0.01 mol / L or more, or 0.05 mol / L or more is more preferable.

  It does not specifically limit about the kind of acid used as an acid solution, A well-known inorganic acid, carboxylic acid, and an ion exchange resin can be used. Specifically, hydrochloric acid, nitrous acid, nitric acid, sulfurous acid, sulfuric acid, thiosulfuric acid, hypophosphorous acid, phosphorous acid, phosphoric acid and other inorganic acids, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid , Caprylic 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 resins, 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 the solvent used as the acid solution is not particularly limited, but water, a protic 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, etc. can be selected as the protic organic solvent, and acetone, ethyl methyl ketone, acetylacetone 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 performing acid immersion is not particularly limited, and can be 10 minutes or longer, 30 minutes or longer, 1 hour or longer, 2 hours or longer, 4 hours or longer, or 6 hours or longer. Moreover, 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 as needed.

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

Both the acid solution and the water can be removed by a known method after completion of acid immersion and washing. As a specific method, a method of removing by suction filtration using a Buchner funnel with filter paper, a method of removing by vacuum drying, a method of removing a supernatant by leaving a liquid standing, and the like can be used. The number of times of performing acid dipping and washing with water is not particularly limited, and the operation of removing the liquid after completion of acid dipping and washing may be omitted as necessary.
After removing the liquid by the above method, the phosphorus-containing polyaniline can be dried as necessary. A known method can be used for drying. Specifically, there are a method of exposing to a temperature environment around the boiling point of the liquid, a method of putting in a sealed container and drying in a vacuum state, and a method of combining these. Drying can also be performed by baking after removing the liquid.

(Baking)
When the catalyst of the present invention is produced, any conventionally known method can be adopted as a method for calcining polyaniline. Moreover, 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, and more preferably 700 to 1100 ° C. The phosphorus-containing polyaniline subjected to acid immersion may be before baking or may be a phosphorus-containing polyaniline fired body that has been fired at least once.

  The time for performing the baking 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. Moreover, 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 as needed. If the firing time is too long, the recovered amount of the fired body is reduced, and it may be difficult to recover the fired body.

  According to one preferred embodiment, firing is preferably performed until the phosphorus-containing polyaniline has a certain degree of carbonization, and the time until such a state is reached is preferably set as the firing time. For example, in a preferred embodiment, calcination can be performed until the weight of polyaniline is reduced to some extent by thermal decomposition. The weight reduction 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 reduction 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, the firing can be performed until pyrolysis to the same extent as when fired at 900 ° C. for 5 minutes.

Here, the weight reduction rate is calculated based on the formula of (weight reduction rate) = (numerator) ÷ (denominator) × 100. The numerator and denominator are as follows.
(Molecular): Weight loss (denominator): Total weight of polyaniline and additives (metal salt and bipyridine compound) before firing (excluding solvent).
(Weight reduction rate (%)) =
(1- (weight of fired body after firing) / (total weight of polyaniline and additive (metal salt or bipyridine compound) before firing (excluding solvent))) × 100
The apparatus which performs baking is not specifically limited. An apparatus that can be sealed to some extent during heating is preferred. If it can be sealed to some extent, it is preferable because the inside is easily maintained 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 occurrence of a thermal decomposition reaction in the electric furnace, an apparatus that can release the pressure in such a case is preferable. For example, an air inlet and an exhaust port are attached to a sealed reactor, and a gas (for example, argon gas) for maintaining a non-oxidizing atmosphere is flowed from the air inlet and the exhaust port to maintain an internal non-oxidizing atmosphere. However, it is preferable to use a device that can release pressure from the intake port or the exhaust port when the pressure increases.

(Pulverization)
The phosphorous-containing polyaniline and the phosphorous-containing polyaniline fired body may or may not be subjected to pretreatment and posttreatment when performing acid immersion. Although it does not specifically limit as the method of a pre-processing and a post-processing, Grinding | phosphorating a phosphorus containing polyaniline and a phosphorus-containing polyaniline sintered body is mentioned. Specifically, the pulverization method is a method in which phosphorus-containing polyaniline and a phosphorus-containing polyaniline fired body are placed in a mortar and crushed with a pestle. The method of performing, the method of grind | pulverizing in a grinder, such as a ball mill, a jet mill, an airflow grinder, etc. can be used.

  Although the reduction catalyst of the present invention exhibits high oxygen reduction activity without performing pretreatment and post-treatment by pulverization, the particle diameters of the phosphorus-containing polyaniline and the phosphorus-containing polyaniline calcined product are obtained by performing the pre-treatment and post-treatment by pulverization. Is smaller, and the surface area is improved. Therefore, the effect of catalytic activity by acid immersion can be further enhanced, which is more preferable.

  Embodiments of each step of adding a bipyridine compound, adding a catalyst metal, acid dipping, firing, and pulverization were given as steps for obtaining a reduction catalyst having high oxygen reduction activity from the phosphorus-containing polyaniline of the present invention. At least one or more of these steps may be performed as necessary, and at least two or more of the steps of adding a bipyridine compound, adding a catalytic metal, acid immersion, and washing with water may be performed simultaneously. . Although the order of these steps is not particularly limited, it is more preferable to select a calcination step and a pulverization step as the final stage of the step because a reduction catalyst with higher oxygen reduction activity can be obtained. Further, the firing step may be performed twice or more. In this case, it is preferable that the step of adding the metal compound or the bipyridine compound is performed at a step before the first firing step. Moreover, also when performing a baking process 2 times or more, it is preferable to perform a baking process in the last step of a process, and it is more preferable to perform a grinding | pulverization process as needed after that. A more preferable step is to perform a pulverization step after the final firing step.

As a specific process order,
1. 1. Crushing step → bipyridine compound addition step → firing step 2. Acid dipping step → Metal compound and bipyridine compound addition step → Firing step 3. Addition process of metal compound → firing process Addition process of metal compound → Firing process → Acid dipping process → Firing process → Grinding process,
5. Examples include acid immersion and metal compound addition step → firing step → pulverization 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 catalytic metal such as platinum. The binder according to the present invention can be used as a fuel cell material because polyaniline exhibits excellent proton conductivity. Furthermore, since the binder of the present invention also has conductivity (electric conductivity), it can be suitably used as a binder for fuel cells.

(Battery manufacturing method)
The method for producing a battery using the catalyst of the present invention is not particularly limited. Various conventionally known methods can be used as a PEFC production method. 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 to form a battery in combination with other members of the battery.

  In forming the electrode layer, for example, a binder liquid is prepared using a binder such as Nafion and a solvent as necessary, and the catalyst prepared by the above-described method is added to the binder liquid to form a catalyst ink. The catalyst ink can be applied onto a substrate and dried.

  When forming a catalyst layer using the binder of this invention, a conventionally well-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 comprising particles composed of a catalyst metal and a catalyst carrier. As the catalyst metal, for example, platinum, gold, copper, palladium, rhodium, ruthenium, iridium, osmium, rhenium, and two or more kinds of these alloys can be used. For example, carbon (for example, carbon black) can be used as the catalyst carrier.

  When using the binder of this invention for a negative electrode catalyst layer, a catalyst is a catalyst which accelerates | stimulates ionization of hydrogen which consists of a particle | grain comprised from a catalyst metal and a catalyst support | carrier, for example. As the catalyst metal, for example, platinum, gold, copper, palladium, rhodium, ruthenium, iridium, osmium, rhenium, and two or more kinds of these alloys can be used. For example, carbon (for example, carbon black) can be used as the catalyst carrier.

  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 samples in the following examples is FT-01X manufactured by FULL-TECH. Data on the activity evaluation of the oxygen reduction reaction is based on the electrochemical analyzer ALS608E manufactured by BAS, 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. It measured using the rotating ring disk electrode apparatus RRDE-3A to analyze.

(electrode)
The electrolyte is an oxygen-saturated 0.1M phosphoric acid aqueous solution, the reference electrode is a silver / silver chloride (3M NaCl) electrode, the counter electrode is a platinum electrode, and the working electrode is a glassy carbon disk electrode (outer diameter 12 mm). Among them, the diameter of the electrode part was 3 mm or 4 mm).

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

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

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

(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 International Publication WO2014 / 167818.

(1A) Synthesis of Compound (6) After the inside of the flask was dried, 804 mg (3.47 mmol) of 4-bromo-2-nitroanisole, 405 mg (3.82 mmol) of Na ₂ CO ₃ , Pd (OAc) ₂ under a nitrogen atmosphere 78 mg (0.35 mmol), diethyl phosphite 0.9 mL (6.99 mmol), and xylene 3 mL were added. The mixture was stirred at 120 ° C. for 24 hours, cooled to room temperature, the solid was filtered off through celite, and the filter cake was washed with CH ₂ Cl ₂ . The obtained filtrate and the washing liquid of the filter cake were mixed and the solvent was distilled off, followed by purification by column chromatography to obtain 807 mg of a yellow liquid. Thereafter, Kugelrohr distillation (100 ° C./133 Pa × 30 minutes) was performed to distill off the remaining diethyl phosphite, and 689 mg (2. 38 mmol, 69% yield).

(1B) Synthesis of Compound (7) After drying 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 ( After adding 5 wt% of Pd in C), the mixture was stirred at room temperature, and the system was placed in a hydrogen atmosphere. After 4.5 hours, 5% Pd-C was further added and stirred at room temperature for 2 hours to complete the reaction. The resulting reaction mixture was filtered off using celite, and the filtrate was evaporated to obtain 830 mg of brown liquid diethyl 3-amino-4-methoxyphenylphosphonate. Next, 5 mL (60 mmol) of 35% hydrochloric acid was added, and 90 ° C. was maintained for 15 hours to complete the reaction. The solvent of the obtained reaction mixture was distilled off, and the solid was dried at 133 Pa under reduced pressure at room temperature to give 672 mg (2.80 mmol, 2-step yield 72%) of the desired compound 3-amino-4-methoxy. A solid of phenylphosphonic acid hydrochloride was obtained. The product was used in the next reaction without further purification.

(1C) Synthesis of Compound (8) 150 mg (0.63 mmol) of 3-amino-4-methoxyphenylphosphonic acid hydrochloride and 1.48 mL of water were placed in a flask and 2.96 mL (2.96 mmol) of 1M-NH ₃ aqueous solution. After cooling to 3 ° C., 0.74 mL (0.93 mmol) of a 1.25M- (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 complete the reaction. The obtained reaction product was added to 50 mL of acetone to precipitate a solid, and further stirred at room temperature for 30 minutes. The solid was filtered off with a Kiriyama funnel and washed with several mL of methanol. The obtained solid was dried at 40 ° C. under a reduced pressure of 133 Pa to obtain 184 mg of the objective compound as a green solid.

(Example 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 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 a PMAP / pyridine binder solution. Here, in order to disperse PMAP well, 0.5 equivalent of pyridine was added to the monomer unit of PMAP. Take 40 μL from the prepared binder liquid and mix it with 2.4 mg of Pt / C (containing 10 wt% Pt in C, hereinafter referred to as Pt / C (10 wt%)) powder and 50 μL of isopropanol, Deionized water was added to make 1 mL. A catalyst ink was prepared by subjecting the obtained mixture to ultrasonic irradiation for 3.5 hours. Next, 3 μL was taken from the catalyst ink, and this was applied to a disk electrode and naturally dried to prepare a measurement sample. Thereafter, 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)
Nafion binder liquid 40 μL was taken and 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 subjecting the obtained mixture to ultrasonic irradiation for 3.5 hours. Next, 1.5 μL was taken from the catalyst ink, applied to a disk electrode, and naturally dried to prepare a measurement sample. Thereafter, 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 results are shown in FIG. As a result of the measurement, it was found that PMAP showed binder performance equivalent to that of Nafion.

(Example using PMAP fired body as catalyst)
(Example 2)
[Synthesis of PMAP fired body]
In a mullite crucible (5 mL), 20.0 mg of PMAP synthesized in Synthesis Example 1 was put, covered, placed in an electric furnace, and baked in an argon stream. After 5 minutes from the start of the argon gas flow, the temperature was raised at a rate of 100 ° C./min, 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 are abbreviated as PMAP700, PMAP800, and PMAP900, respectively.

[Evaluation of oxygen reduction reaction activity of PMAP fired body]
The activity of oxygen reduction reaction was evaluated for the PMAP fired bodies (PMAP700, PMAP800, PMAP900) synthesized by the above method. The oxygen reduction reaction activity was measured by the measurement method described in “Electrochemical measurement”. The result is shown in FIG.

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

(Example using PMAP / 4,4′-bipyridyl fired body as a catalyst)
(Example 3)
[Synthesis of PMAP / 4,4′-bipyridyl fired body]
N, N-dimethylformamide (DMF) was added to a mullite crucible (5 mL) to which 20.0 mg of PMAP synthesized in Synthesis Example 1 and 1.9 mg of 4,4′-bipyridyl (0.5 equivalent to the monomer unit of PMAP) were added. 100 μL was added. The solid matter was stirred while being crushed well with a glass rod, covered, placed in an electric furnace, and fired under an argon stream. After 5 minutes from the start of gas flow, the temperature was raised to 135 ° C. over 2 minutes and held for 5 minutes. Then, it heated up to 210 degreeC in 2 minutes, and hold | maintained for 3 minutes. Thereafter, 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 fired product]
The PMAP / 4,4′-bipyridyl fired body synthesized by the above method (PMAP / bpy / DMF / 900) was evaluated for oxygen reduction reaction activity. The oxygen reduction reaction activity was evaluated by the measurement method described in “Electrochemical measurement”. The results are shown in FIG.

  As a result of the measurement, oxygen reduction activity was recognized although not as high as Pt / C. When compared 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 polyaniline (hereinafter referred to as PANI) calcined product as a catalyst)
(Comparative Example 2)
[Synthesis of PANI sintered body]
PANI (manufactured by Sigma-Aldrich, 530689-10G, Mw: ˜65,000) was used. Lett. 2012, 142, 1244-1250. Synthesis was carried out with reference to the firing method. To a mullite crucible (5 mL) to which 200.0 mg of PANI was added, 1.2 mL of deionized water was added and stirred well, covered, placed in an electric furnace, and baked under an argon stream. After 5 minutes from the start of gas flow, the temperature was raised to 95 ° C. over 1 minute and held for 5 minutes. Then, it heated up to 130 degreeC in 1 minute, and hold | maintained for 5 minutes. Thereafter, 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 sintered body]
As a comparative example, the activity of the oxygen reduction reaction was evaluated for the PANI sintered body (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 results are shown in FIG.

  As a result of the measurement, oxygen reduction activity was recognized although not as high as Pt / C. When compared 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 that PMAP900 has 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 (diethylaminophenylphosphonate)
A rotor is placed in a container (φ34) for ChemiStation Personal Synthesizer PPV (manufactured by EYELA), and polyaniline 1.81 g (5.0 mmol (aniline tetramer basis)), SIGMA-ALDRICH: polyaniline (emeraldine base) weight average molecular weight about 10,000). Subsequently, 100 mL of NMP was added to the container and stirred. Thereafter, ultrasonic waves were irradiated for 5 minutes. Thereto, 1.71 g (7.5 mmol) of ammonium persulfate was added and 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 phosphite. The mixture was heated to 60 ° C. using a ChemiStation Personal Synthesizer PPV (manufactured by EYELA), and stirring was continued. A reflux tube was attached to the apparatus, and when the mixture was heated and stirred, it 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. Thereafter, a blackish green solid was obtained by suction filtration. Subsequently, in order to perform dedoping, the obtained solid was put into a conical beaker containing 400 mL of 0.15 mol / L aqueous ammonia, stirred, and subjected to ultrasonic irradiation for 10 minutes. Thereafter, a black-blue solid was obtained by suction filtration. Next, the solid after de-doping was put into a conical beaker containing 400 mL of deionized water, stirred, and subjected to ultrasonic irradiation for 10 minutes. Thereafter, a black-blue solid was obtained by suction filtration. Moreover, the obtained solid was transferred to a conical beaker, 200 mL of diethyl ether was poured therein, 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 solid was 2.49g.

(Synthesis of diethyl polyaniline phosphonate (hereinafter referred to as PANI-PDE))
(Synthesis Example 3)
A rotor is placed in a container (φ34) for ChemiStation Personal Synthesizer PPS-CTRL1 (manufactured by EYELA), and 214.5 mg of phosphonated polyaniline (0.34 mmol (based on aniline tetramer), synthesized in Synthesis Example 2) is added. It was. Subsequently, 20 mL of NMP was added to the container and stirred. Thereafter, ultrasonic waves were irradiated for 5 minutes. Thereto, 119.8 mg (0.53 mmol) of ammonium persulfate was added, 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 phosphite. 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 apparatus, and when the mixture was heated and stirred, it 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 washing with deionized water. Thereafter, a distillation apparatus was assembled and heated under reduced pressure to distill off the solvent. When distilling off the solvent, an alkali trap was used. After most of the solvent was distilled off, about 40 mL of toluene was added, and ultrasonic waves were applied for 5 minutes. Then, it heated again under reduced pressure and the solvent was distilled off. 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 put into a conical beaker containing 200 mL of 0.15 mol / L ammonia water, stirred, and subjected to ultrasonic irradiation for 10 minutes. Thereafter, a black solid was obtained by suction filtration. Next, the solid after de-doping was put into a conical beaker containing 200 mL of deionized water, stirred, and subjected to ultrasonic irradiation for 10 minutes. Thereafter, a black solid was obtained by suction filtration. Further, 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 phosphonated polyaniline (0.33 mmol (aniline tetramer standard), synthesized in Synthesis Example 2) was added. Thereto were added 20 mL of acetonitrile (ultra dehydration) and 2.2 mL (16.8 mmol) of trimethylsilyl bromide. The mixture was heated to 90 ° C. using a ChemiStation Personal Synthesizer PPS-CTRL1 (manufactured by EYELA), and the mixture was stirred and reacted. 300 mL of deionized water was poured into a conical beaker, and after 3.5 hours from the start of the reaction, the reaction solution was added thereto while washing with deionized water. Thereafter, a black solid was obtained by suction filtration using an alkali trap. The obtained solid was vacuum-dried under heating (40 ° C.) overnight. The yield of solid was 117.2 mg.

(Example using PMAP / FeCl ₃ fired body and PMAP fired body as catalyst)
Example 4
[Synthesis of PMAP / FeCl ₃ fired body and PMAP fired body]
Add 20.0 mg of PMAP obtained in Synthesis Example 1 and FeCl ₃ / DMF solution (0.489 M, 102 μL) to a mullite crucible (5 mL), stir well, place in an electric furnace, and fire under argon flow Went. After 5 minutes from the start of the argon gas flow, the temperature was raised to 130 ° C. in 2 minutes and held for 5 minutes. Thereafter, the temperature was raised to 180 ° C. in 2 minutes and held for 5 minutes. Thereafter, the temperature was raised at a rate of 100 ° C./min, and the temperature was held for 5 minutes after reaching 900 ° C. Then, 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. The same operation was performed using DMF (102 μL) instead of the FeCl ₃ / DMF solution to obtain 7.3 mg of a black solid. Hereinafter, the sample obtained here is abbreviated as PMAP / 900.

(Examples using a PANI-PDE / FeCl ₃ fired body and a PANI-PDE fired body as a catalyst)
(Example 5)
[Synthesis of PANI-PDE / FeCl ₃ fired body and PANI-PDE fired body]
Firing was performed 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 a gray solid was obtained. Hereinafter, the sample obtained here abbreviated as _{PANI-PDE / FeCl 3/900} . The same operation was performed using DMF (129 μL) instead of the FeCl ₃ / DMF solution to obtain 4.1 mg of a black solid. Hereinafter, the sample obtained here is abbreviated as PANI-PDE / 900.

(Examples using PANI-PA / FeCl ₃ calcined body and PANI-PA calcined body as catalyst)
(Example 6)
[Synthesis of PANI-PA / FeCl ₃ fired body and PANI-PA fired body]
Firing was performed 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 a gray solid was obtained. Hereinafter, the sample obtained here abbreviated as _{PANI-PA / FeCl 3/900} . The same operation was performed using DMF (157 μL) instead of the FeCl ₃ / DMF solution to obtain 8.5 mg of a black solid. Hereinafter, the sample obtained here is abbreviated as PANI-PA / 900.

[Oxygen reduction reaction activity evaluation of fired bodies of Examples 4 to 6]
About each baked body of Examples 4-6 synthesize | combined by said method, activity evaluation of oxygen reduction reaction was performed. The oxygen reduction reaction activity was evaluated by the measurement method described in “Electrochemical measurement”. The results are shown in FIGS.

As a result of the measurement, although not as much as Pt / C, oxygen reduction activity was observed in any sample. When FeCl ₃ was added, the oxygen reduction start potential shifted in the positive direction, and the oxygen reduction activity was improved. In addition, as comparison data, the blank and Pt / C data obtained in Example 1 are also shown.

(Example 7)
[A fired PAP / FeCl ₃ fired body after acid dipping and re-fired]
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 cooling to room temperature, the supernatant was removed using a Pasteur pipette. Deionized water (about 2 mL) was added thereto, and the mixture was allowed to stand by being irradiated with ultrasonic waves for 1 minute. Thereafter, 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 water 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), was placed in an electric furnace with a lid. The temperature was raised at a rate of 100 ° C./min after 5 minutes from the start of the argon gas flow, and the temperature was maintained for 5 minutes after reaching 900 ° C. Then, 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 test tube (Marume, N-16) and carefully ground with a round bottom glass rod.

[Evaluation of oxygen reduction reaction activity of the PMAP / FeCl ₃ fired body after acid dipping and re-baking treatment]
The PMAP / FeCl ₃ fired body synthesized by the above method was subjected to an acid immersion / refired fired body, and the activity of the oxygen reduction reaction was evaluated. The oxygen reduction reaction activity was evaluated by the measurement method described in “Electrochemical measurement”. The results are shown in FIG.

  As a result of the measurement, oxygen reduction activity equivalent to Pt / C was recognized. It was found that the oxygen reduction starting potential was shifted in the positive direction when re-baking after acid dipping, and the oxygen reduction activity was improved. In addition, as comparison 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 PEFC.

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

  As mentioned above, although this invention has been illustrated using preferable embodiment of this invention, this invention should not be limited and limited to this embodiment. It is understood that the scope of the present invention should be construed only by the claims. It is understood that those skilled in the art can implement an equivalent range based on the description of the present invention and the common general technical knowledge from the description of specific preferred embodiments of the present invention. Patents, patent applications, and documents cited herein should be incorporated by reference in their entirety, as if the contents themselves were specifically described herein. Understood.

Claims (14)

A catalyst for promoting a reduction reaction,
The following general formula (1):
− (A ¹ ) _k − (1)
Wherein the polyaniline or a fired body thereof is represented by:
Each A ¹ is independently a substituted or unsubstituted aniline monomer residue;
A ¹ each independently has m phosphonic acid residues R ^p and n substituents R;
Phosphonic acid residue R ^p is represented by the following formula:

Where
M ¹ and M ² are each independently a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, an aralkyl group having 7 to 34 carbon atoms, an aryl group having 6 to 30 carbon atoms, an alkali metal, an alkaline earth metal, 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,
When ^{one of} M ¹ or M ² is an alkaline earth metal, the alkaline earth metal atom is bonded to two O ⁻ in one R ^p group, and M ¹ or M ² Or a structure in which the alkaline earth metal atom cross-links O ⁻ of two R ^p groups,
R each independently represents a 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, an alkylthio group having 1 to 15 carbon atoms, 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 an ester residue, a nitro group, and a cyano group;
m is each independently an integer of 1 to 4,
n is each independently an integer of 0 to 3,
In each aniline monomer residue, the sum of m and n is independently 4 or less,
k is an integer of 4 to 3000,
catalyst.   The catalyst according to claim 1, further comprising a bipyridine compound.   The catalyst according to claim 1 or 2, further comprising a compound of iron, cobalt, or nickel.   The catalyst according to any one of claims 1 to 3, comprising a calcined product of the polyaniline.   The catalyst according to claim 4, wherein the calcined body is calcined at a temperature of 700 ° C or higher.   The catalyst according to any one of claims 1 to 5, wherein the catalyst promotes an oxygen reduction reaction.   The catalyst according to any one of claims 1 to 6, which promotes an oxygen reduction reaction at a positive electrode of a fuel cell.   The catalyst according to any one of claims 1 to 7, wherein the number of phosphonic acid residues introduced into the polyaniline is 10% or more based on the number of aniline monomer residues.   A fuel cell comprising the catalyst according to any one of claims 1 to 8 in a positive electrode. The following general formula (1):
− (A ¹ ) _k − (1)
A solid polymer fuel cell binder containing polyaniline represented by the formula:
Each A ¹ is independently a substituted or unsubstituted aniline monomer residue;
A ¹ each independently has m phosphonic acid residues R ^p and n substituents R;
Phosphonic acid residue R ^p is represented by the following formula:

Where
M ¹ and M ² are each independently a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, an aralkyl group having 7 to 34 carbon atoms, an aryl group having 6 to 30 carbon atoms, an alkali metal, an alkaline earth metal, 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,
Provided that at least one M ^{1 in the} polyaniline is a hydrogen atom;
When ^{one of} M ¹ or M ² is an alkaline earth metal, the alkaline earth metal atom is bonded to two O ⁻ in one R ^p group, and M ¹ or M ² Or a structure in which the alkaline earth metal atom cross-links O ⁻ of two R ^p groups,
R each independently represents a 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, an alkylthio group having 1 to 15 carbon atoms, 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 an ester residue, a nitro group, and a cyano group;
m is each independently an integer of 1 to 4,
n is each independently an integer of 0 to 3,
In each aniline monomer residue, the sum of m and n is independently 4 or less,
k is an integer of 4 to 3000,
A binder for polymer electrolyte fuel cells.   The binder according to claim 10, wherein the number of phosphonic acid residues introduced into the polyaniline is 10% or more based on the number of aniline monomer residues.   A polymer electrolyte fuel cell comprising the binder according to claim 10 or 11. A method for producing the catalyst according to any one of claims 1 to 8, comprising:
The following general formula (2):
− (A ² ) _k − (2)
Including a step of obtaining a phosphorus-containing polyaniline by conducting a phosphonation reaction on the polyaniline compound represented by the formula, and a step of forming a catalyst from the phosphorus-containing polyaniline, wherein
A ² is a substituted or unsubstituted aniline monomer residue,
Each A ² independently has n substituents R;
R, n and k are as defined in claim 1;
Method. A method for producing the binder according to claim 10 or 11,
The following general formula (2):
− (A ² ) _k − (2)
A step of obtaining a phosphorus-containing polyaniline by conducting a phosphonation reaction on the polyaniline compound represented by the formula: and a step of forming a binder from the phosphorus-containing polyaniline, wherein
A ² is a substituted or unsubstituted aniline monomer residue,
Each A ² independently has n substituents R;
R, n and k are as defined in claim 10;
Method.