JP7457323B2 - Phosphonium-containing polymer - Google Patents

Description

The present invention relates to a phosphonium-containing polymer. More specifically, the present invention relates to a phosphonium-containing polymer, a phosphonium-containing compound, a method for producing the same, an anion exchange membrane, and an electrolyte material that are suitable for use as an electrolyte material in fuel cells and water electrolysis devices.

In recent years, it is expected that hydrogen will be utilized as an energy source, such as in fuel cells and water electrolyzers, and various research and development efforts have been made.
Proton exchange membranes (PEMs) are used as solid polymer electrolyte membranes, which are the core components of fuel cells, water electrolysis devices, etc., but sulfonic acid-based materials such as Nafion (registered trademark) are Because it is strongly acidic and highly corrosive, expensive metals are required for surrounding parts (for example, in a water electrolysis device that includes a proton conductive membrane, Ti, Pt, etc. are used for the power supply, and Pt, Pt, etc. are used for the catalyst). (Ir, etc. are required for the bipolar plate, and Ti, etc. are required for the bipolar plate, respectively), causing an increase in cost. On the other hand, if an anion exchange membrane (AEM) that conducts hydroxide ions is used instead of the proton conductive membrane, it is possible to use inexpensive metal members for the peripheral members.

In addition to anion conductivity, basic properties such as chemical stability are important for the polymer constituting the anion exchange membrane.
Quaternary ammonium groups have conventionally been used as anion exchange groups responsible for anion conductivity (see, for example, Patent Documents 1 to 5). Furthermore, there are examples of research on anion-conducting materials containing quaternary phosphonium groups (see, for example, Non-Patent Document 1).

Japanese Patent Application Publication No. 2018-70782 Japanese Patent Application Publication No. 2013-107916 JP2015-125888A JP2010-92660A International Publication No. 2008/022775

Angew. Chem. Int. Ed. 2009, 48, 6499-6502

However, the quaternary ammonium group has poor chemical stability because it decomposes due to Hofmann elimination, nucleophilic substitution reaction, etc. especially under high temperature and strongly basic conditions. Furthermore, there is room for improvement in the durability of anion conductive materials containing quaternary phosphonium groups. There was a desire for a new material that has excellent chemical stability (durability) even under high temperature and basic conditions.

The present invention has been made in view of the above-mentioned current situation, and an object of the present invention is to provide a material that has sufficient anion conductivity and is excellent in durability.

The inventors have conducted various investigations into materials that have sufficient anion conductivity and excellent durability, and have discovered that a phosphonium-containing polymer having a specific phosphonium cation structure and its counter anion has sufficient anion conductivity and excellent durability even at high temperatures and under basic conditions, and have come to the conclusion that the above-mentioned problem can be successfully solved. Furthermore, the inventors have discovered that phosphonium-containing compounds having specific phosphonium cations also have excellent durability even at high temperatures and under basic conditions, and may be used for various purposes, and have arrived at the present invention.

（式中、Ｒ^１～Ｒ^４は、同一又は異なって、水素原子、置換基、又は、ポリマーが有する他の構造との直接結合を表し、Ｒ^１～Ｒ^４の少なくとも１つは、ポリマーが有する他の構造との直接結合であるか、又は、当該直接結合を有する置換基である。Ｒ^１～Ｒ^４の少なくとも１つは、オルト位の置換基であって、炭化水素基、酸素原子を介した炭化水素基、若しくは、ハロゲン原子であるか、又は、Ｒ^１～Ｒ^４の少なくとも２つは、オルト位の置換基である。Ｒ^１～Ｒ^４は、それぞれ、環構造に複数個結合していてもよく、複数個の置換基が結合して更に環構造を形成していてもよい。Ｘ^－は、カウンターアニオンを表す。）で表される構造を有することを特徴とするホスホニウム含有ポリマーである。 That is, the present invention provides a phosphonium-containing polymer, wherein the polymer has the following general formula (1);

(In the formula, R ¹ to R ⁴ are the same or different and represent a hydrogen atom, a substituent, or a direct bond with another structure possessed by the polymer, and at least one of R ¹ to R ⁴ is or a substituent having the direct bond.At least one of R ¹ to R ⁴ is a substituent at the ortho position, and is a hydrocarbon group, an oxygen atom, or a substituent having the direct bond. is a hydrocarbon group or a halogen atom, or at least two of R ¹ to R ⁴ are substituents at the ortho position. R ¹ to R ⁴ each have a plurality of substituents in the ring structure. A phosphonium characterized by having a structure represented by the following formula (which may be bonded, or a plurality of substituents may be bonded to form a ring structure. X ^- represents a counter anion) Containing polymer.

（式中、Ｒ^１～Ｒ^４は、同一又は異なって、水素原子、又は、置換基を表す。Ｒ^１～Ｒ^４の少なくとも１つは、オルト位の置換基であって、炭化水素基、酸素原子を介した炭化水素基、若しくは、ハロゲン原子であるか、又は、Ｒ^１～Ｒ^４の少なくとも２つは、オルト位の置換基である。Ｒ^１～Ｒ^４は、それぞれ、環構造に複数個結合していてもよく、複数個の置換基が結合して更に環構造を形成していてもよい。Ｘ^－は、カウンターアニオンを表す。）で表されることを特徴とするホスホニウム含有化合物でもある。 The present invention also provides the following general formula (1);

(In the formula, R ¹ to R ⁴ are the same or different and represent a hydrogen atom or a substituent. At least one of ^{R 1} to R ⁴ is a substituent at the ortho position, and a hydrocarbon group, A hydrocarbon group via an oxygen atom, a halogen atom, or at least two of R ¹ to R ⁴ are substituents at the ortho position. ^{R 1} to R ⁴ each have a ring structure A phosphonium-containing compound characterized in that a plurality of substituents may be bonded, or a plurality of substituents may be bonded to form a ring structure.X ^- represents a counter anion. It is also a compound.

The present invention further provides a method for producing the phosphonium-containing polymer of the present invention or the phosphonium-containing compound of the present invention, wherein the production method includes a step of reacting a phosphine compound with an aryne. Alternatively, it is also a method for producing a phosphonium-containing compound.

The phosphonium-containing polymer of the present invention has the above-described structure and has sufficient anion conductivity and excellent durability. The phosphonium-containing compound of the present invention has the above-described structure and has excellent durability.

1 is an NMR spectrum showing the results of ³¹ P-NMR measurement of a phosphonium-containing polymer of an example. This is a TGA curve obtained by measuring the thermal stability of an anion exchange membrane by thermogravimetry (TGA).

The present invention will be explained in detail below.
Note that a combination of two or more of the individual preferred embodiments of the present invention described below is also a preferred embodiment of the present invention.

<Phosphonium-containing polymer of the present invention>
The phosphonium-containing polymer of the present invention has the above cationic structure (the cationic structural portion in the structure represented by the above general formula (1)). The position of the cationic structure may be in the main chain or in the side chain in the polymer.
When the cationic structure is located in the main chain of the polymer, the phosphonium-containing polymer of the present invention may be a homopolymer having the above cationic structure in the main chain, or a copolymer having the above cationic structure and another structure (structural unit) in the main chain.
When the cationic structure is located in a side chain in a polymer, the phosphonium-containing polymer of the present invention may have the cationic structure in a part of the side chain, or may have the cationic structure in the entirety of the side chain.

In the above cation structure, R ¹ to R ⁴ are the same or different and represent a hydrogen atom, a substituent, or a direct bond with another structure possessed by the polymer.
The substituent is usually monovalent or divalent, although its valence (valency indicating atomic valence) is not particularly limited.
The monovalent substituent is not particularly limited, but preferable examples thereof include a monovalent organic group, an amino group, a halogen atom, and the like. The monovalent organic group includes a monovalent hydrocarbon group (more preferably an aliphatic saturated hydrocarbon group [alkyl group] having 1 to 18 carbon atoms), an aliphatic unsaturated hydrocarbon group having 2 to 18 carbon atoms [ [alkenyl group], aromatic hydrocarbon group [aryl group] having 6 to 18 carbon atoms, or aralkyl group [e.g. benzyl group] having 7 to 18 carbon atoms, via an oxygen atom having 1 to 18 carbon atoms. A hydrocarbon group (for example, an alkoxy group having 1 to 18 carbon atoms), an alkylthio group having 1 to 18 carbon atoms, a group represented by the general formula: -AC ₆ H _(5-n) R ⁵ _n (R ⁵ are the same or different and represent a hydrogen atom, a substituent, or a direct bond with another structure possessed by the polymer, and the same ones as R ¹ to R ⁴ can be used.A is S, NR ⁶ , or , O, and R ⁶ represents a hydrogen atom or a monovalent organic group. n is an integer of 1 to 5. As the monovalent organic group, preferred monovalent organic groups described below are listed. Monovalent organic groups such as ) are preferable, and more preferable are hydrocarbon groups, hydrocarbon groups via oxygen atoms, or halogen atoms, and hydrocarbon groups, hydrocarbon groups via oxygen atoms, etc. The hydrocarbon group in the hydrogen group is particularly preferably an aliphatic saturated hydrocarbon group (alkyl group) having 1 to 18 carbon atoms or an aromatic hydrocarbon group (aryl group) having 6 to 18 carbon atoms, respectively. .
Note that the aralkyl group refers to a group having an aromatic ring together with an aliphatic hydrocarbon group, such as a benzyl group.
Examples of the divalent substituent include those having a structure in which one hydrogen atom is further removed from the monovalent substituent described above, an oxygen atom, a sulfur atom, and the like. The divalent substituent may be bonded to the benzene ring represented by general formula (1), and may also be bonded to other structures possessed by the polymer, or the divalent substituents may be bonded to each other. .
Among these, the substituent is preferably a monovalent substituent.

At least one of the above R ¹ to R ⁴ is a direct bond to another structure of the polymer, or a substituent having the direct bond.
In this specification, the other structure that the polymer has may be another structure represented by general formula (1) or another structure (such as a structural unit).
For example, when the position of the cation structure is the main chain in the polymer, two of the above R ¹ to R ⁴ each have a direct bond with another structure of the polymer, or have the direct bond. Preferably, it is a substituent. For example, it is preferable that R ² and R ⁴ are each a direct bond to another structure of the polymer or a substituent having the direct bond.
In addition, when the position of the cation structure is a side chain in the polymer, one of the above R ¹ to R ⁴ is a direct bond with another structure that the polymer has, or has the direct bond. It is preferably a substituent (for example, a direct or indirect bond to the main chain structure).

In the structure represented by the above general formula (1), R ¹ to R ⁴ may each be bonded to a ring structure in plural numbers, or may be bonded to a plurality of substituents to further form a ring structure. It's okay.
For example, two adjacent divalent substituents may be bonded together to form a condensed ring structure such as a naphthalene ring or benzimidazole ring together with the benzene ring to which the substituents are bonded.

At least one of the above R ^{1 to} R ⁴ is a substituent at the ortho position, and is a ^hydrocarbon group, a hydrocarbon group via an oxygen atom, or a halogen atom, or At least two are ortho substituents.
The above-mentioned hydrocarbon group via oxygen may be one consisting of a hydrocarbon group and an oxygen atom (ether bond). Preferred examples include those that are bonded.
The halogen atom is preferably a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, and more preferably a fluorine atom or a chlorine atom.
Among these, at least one of R ¹ to R ⁴ is preferably an ortho-position hydrocarbon group or a hydrocarbon group via an oxygen atom.
The hydrocarbon group in the hydrocarbon group and the hydrocarbon group via oxygen are not particularly limited, but are aliphatic saturated hydrocarbon groups (alkyl groups) having 1 to 18 carbon atoms, and aliphatic unsaturated groups having 2 to 18 carbon atoms. Preferred examples include saturated hydrocarbon groups (such as alkenyl groups), aromatic hydrocarbon groups (aryl groups) having 6 to 18 carbon atoms, and aralkyl groups having 7 to 18 carbon atoms.
The hydrocarbon group in the hydrocarbon group and the hydrocarbon group via oxygen is more preferably an aliphatic saturated hydrocarbon group (alkyl group) having 1 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms. group (aryl group) or an aralkyl group having 7 to 18 carbon atoms.
Among these, it is particularly preferable that at least one of the above R ¹ to R ⁴ is a hydrocarbon group.
In addition, when at least two of the above R ¹ to R ⁴ are substituents at the ortho position, the substituent is not limited to a hydrocarbon group, a hydrocarbon group via an oxygen atom, or a halogen atom, and the valence thereof The monovalent substituents and divalent substituents mentioned above can be suitably used, although the type thereof is not limited.

In the structure represented by the above general formula (1), up to eight substituents can be bonded to the ortho position.
Among the above R ¹ to R ⁴ , it is preferable that at least two of the ortho-position substituents are a hydrocarbon group, a hydrocarbon group via an oxygen atom, or a halogen atom; More preferably 3, still more preferably at least 4, even more preferably at least 5, even more preferably at least 6, even more preferably at least 7. , eight are particularly preferred.

Further, among the above R ¹ to R ⁴ , the number of substituents at the ortho position that is a hydrocarbon group is preferably at least one, more preferably at least two, and at least three. More preferably, there are at least four, particularly preferably at least four.
Preferably, there are at least four substituents at the ortho position, at least three of which are hydrocarbon groups.
Among them, for example, among the above R ¹ to R ⁴ , at least four substituents at the ortho position are a hydrocarbon group, a hydrocarbon group via an oxygen atom, or a halogen atom, It is particularly preferred that at least three of these groups are hydrocarbon groups.

Regarding R ¹ to R ⁴ above, it is preferable that at least two of the four aromatic rings bonded to P have a substituent at the ortho position, and at least three aromatic rings have a substituent at the ortho position. It is more preferable that there is a group, and even more preferable that there is a substituent at the ortho position of each aromatic ring.
Among these, it is preferable that there are at least four substituents at the ortho position, and at least two of the four aromatic rings bonded to P have substituents at the ortho position, and at least three aromatic rings are present. It is more preferred that the substituent be present at the ortho position of the ring, and even more preferred that the substituent be present at the ortho position of each aromatic ring.
Note that the term "substituents are present at the ortho position of an aromatic ring" means that there are substituents at one or two ortho positions of the aromatic ring.

For example, at least one of R ¹ is a monovalent ortho-position substituent, and at least one of each of R ² to R ⁴ is a monovalent ortho-position substituent, and A hydrocarbon group or a halogen atom is preferable. Among these, it is preferable that at least one of R ¹ is a monovalent ortho-position substituent, and at least one of each of R ² to R ⁴ is a monovalent hydrocarbon group.
Preferred monovalent hydrocarbon groups are as described above.

Further, for R ¹ to R ⁴ above, it is preferable that at least one substituent is present at the meta or para position of the aromatic ring bonded to P (any of the aromatic rings bonded to P). Among these, it is more preferable that at least one hydrocarbon group is present at the meta or para position of the aromatic ring bonded to P.

Among these, it is preferable that there be at least four substituents at the ortho position, and at least one substituent at the meta or para position of the aromatic ring bonded to P (any of the aromatic rings bonded to P). . Furthermore, it is more preferable that there are at least four substituents at the ortho position and at least one hydrocarbon group at the meta or para position of the aromatic ring bonded to P.
Furthermore, as described above, in the phosphonium-containing polymer of the present invention, at least one of the above R ¹ to R ⁴ is a substituent at the ortho position, and is a hydrocarbon group, a hydrocarbon group via an oxygen atom, or , at least two of R ¹ to R ⁴ may be substituents (arbitrary substituents) at the ortho position instead of being halogen atoms.
As mentioned above, the above-mentioned substituent (arbitrary substituent) is not particularly limited, but it is preferably the above-mentioned monovalent substituent.

In the structure represented by the above general formula (1), it is preferable that at least three of the above R ¹ to R ⁴ are substituents (arbitrary substituents) at the ortho position, and at least four More preferably, at least 5, still more preferably at least 6, even more preferably at least 7, particularly preferably 8.

In addition, as described above, among the four aromatic rings bonded to P among R ¹ to R ⁴ , at least two of the aromatic rings have a substituent (arbitrary substituent) at the ortho position. It is preferable that there are substituents at the ortho positions of at least three aromatic rings, and it is preferable that there are substituents at the ortho positions of each aromatic ring.

When the phosphonium-containing polymer of the present invention is a copolymer having the structure represented by the above general formula (1) and another structural unit in the main chain, the other structural unit is not particularly limited, but is preferably a structural unit containing an aromatic ring.As the aromatic ring, benzene ring, naphthalene ring, anthracene ring, tetracene ring, pentacene ring, triphenylene ring, pyrene ring, fluorene ring, indene ring, thiophene ring, furan ring, pyrrole ring, benzothiophene ring, benzofuran ring, indole ring, dibenzothiophene ring, dibenzofuran ring, carbazole ring, thiazole ring, benzothiazole ring, oxazole ring, benzoxazole ring, imidazole ring, benzimidazole ring, pyridine ring, pyrimidine ring, pyrazine ring, pyridazine ring, quinoline ring, isoquinoline ring, quinoxaline ring, benzothiadiazole ring, etc. can be mentioned, and as the other structural unit, one or more of these can be used.
It is also preferable that the other structural unit has a polyether structure further containing an oxygen atom, a polyarylene sulfide structure further containing a sulfur atom, or a polysulfone structure.

When the phosphonium-containing polymer of the present invention has the above cation structure in the side chain, the structure of the main chain of the phosphonium-containing polymer of the present invention is not particularly limited, but may include the above-mentioned aromatic ring, polyether structure, polyarylene sulfide structure, polysulfone structure, a structure derived from a polymerizable vinyl group-containing monomer, and a combination thereof. For example, as the main chain, vinyl polymers such as polyolefins and polycycloolefins; polyarylenes such as polyphenylene; polyarylene ethers such as polyphenylene ether; polyarylene sulfides such as polyphenylene sulfide; polysulfone; polyether sulfone; polyimide; polyether Imide: Examples include polyamideimide.

Examples of the phosphonium-containing polymer of the present invention whose main chain is a polyolefin include those having a structure represented by the following (1a).
Examples of the phosphonium-containing polymer of the present invention whose main chain is polyphenylene include those having a structure represented by the following (1b).

In the above formulas (1a) and (1b), R ¹ to R ⁴ are the same as R ¹ to R ⁴ in general formula (1). R ⁵ and A are the same as R ⁵ and A described above. R represents a hydrogen atom, a substituent, or a direct bond to another structure possessed by the polymer, and the same ones as R ¹ to R ⁴ can be used. Note that a plurality of R ⁵ and R may each be bonded to a ring structure, or a plurality of substituents may be bonded to each other to further form a ring structure. m and n are the numbers of repeating units, and m is 1 or more, for example from 1 to 100, preferably from 1 to 50. n is 0 or more, for example from 0 to 100, preferably from 0 to 50.

As the counter anion X ^- possessed by the phosphonium-containing polymer of the present invention, general inorganic salts can be used as counter anions, such as halide ions such as F ^- , Cl ^- , Br ^- , I ^- , hydroxide ions, etc. ion, trifluoromethanesulfonate, etc., and one or more of these can be used.

The phosphonium-containing polymer of the present invention has sufficient anion conductivity and excellent durability, and is useful in solid polymer electrolyte membranes for water electrolysis and alkaline fuel cells, phase transfer catalysts, and photonics. There is a possibility that it can be suitably used in many applications such as an acid generator.

<Phosphonium-containing compound of the present invention>
The phosphonium-containing compound of the present invention is represented by the above general formula (1).

In the above general formula (1), R ¹ to R ⁴ are the same or different and represent a hydrogen atom or a substituent.
At least one of the above R ^{1 to} R ⁴ is a substituent at the ortho position, and is a ^hydrocarbon group, a hydrocarbon group via an oxygen atom, or a halogen atom, or At least two are ortho substituents. Thereby, the phosphonium-containing compound of the present invention has excellent chemical stability.
In the above general formula (1), when the substituents in R ¹ to R ⁴ are divalent substituents, the divalent substituents are bonded to each other. The other substituents represented by R ¹ to R ⁴ in the phosphonium-containing compound of the present invention and their preferred forms are the same as the substituents represented by R ¹ to R ⁴ and their preferred forms in the phosphonium-containing polymer of the present invention described above. be.

As the counter anion X ^- possessed by the phosphonium-containing compound of the present invention, general inorganic salts can be used as counter anions, such as halide ions such as F ^- , Cl ^- , Br ^- , I ^- , and hydroxide ions. ion, trifluoromethanesulfonate, etc., and one or more of these can be used.

The phosphonium-containing compound of the present invention has excellent durability and may be suitably used in many applications such as electrolyte materials, phase transfer catalysts, and photoacid generators.

<Method for producing the phosphonium-containing polymer or phosphonium-containing compound of the present invention>
The method for producing a phosphonium-containing polymer or phosphonium-containing compound of the present invention includes a step of reacting a phosphine compound and an aryne.
By the method for producing a phosphonium-containing polymer or phosphonium-containing compound of the present invention, a quaternary phosphonium structure can be easily formed.

（式中、Ａは、Ｓ、ＮＲ^６、Ｏ、又は、非共有電子対を表し、Ｒ^６は、水素原子又は１価の有機基を表す。Ｒ^２～Ｒ^４は、上述した一般式（１）におけるＲ^２～Ｒ^４と同様である。）で表される化合物であることが好ましい。 The above phosphine compound has the following general formula (2):

(In the formula, A represents S, NR ⁶ , O, or a lone pair of electrons, and R ⁶ represents a hydrogen atom or a monovalent organic group. R ² to R ⁴ are represented by the general formula ( The same as R ² to R ⁴ in 1) is preferable.

（式中、Ｒ^１、Ｒ^５は、一般式（１）におけるＲ^１、Ｒ^５と同様である。） The above aryne is a compound represented by the following general formula (3-1), or a compound represented by the following general formula (3-1) and a compound represented by the following general formula (3-2). It is preferable that

(In the formula, R ¹ and R ⁵ are the same as R ¹ and R ⁵ in general formula (1).)

（式中、ＴＭＳは、トリメチルシリル基を表す。Ｔｆは、トリフルオロメタンスルホニル基を表す。）で表される化合物を、例えばフッ化セシウム等のフッ化物と反応させて得ることができる。 The compounds represented by the above general formula (3-1) or (3-2) are, for example, the following general formula (4-1) or (4-2):

(In the formula, TMS represents a trimethylsilyl group. Tf represents a trifluoromethanesulfonyl group.) It can be obtained by reacting a compound represented by, for example, a fluoride such as cesium fluoride.

The step of reacting the phosphine compound and aryne can be performed in an organic solvent such as acetonitrile. The reaction temperature is preferably 15 to 60°C, for example. The reaction time is preferably, for example, 1 to 48 hours. The pressure conditions are not particularly limited, and may be normal pressure, increased pressure, or reduced pressure.
In addition, the compound represented by the above general formula (4-1) or (4-2) is reacted with a fluoride to obtain the compound represented by the above general formula (3-1) or (3-2). The step can be performed simultaneously with the reaction step described above. The method for producing the phosphonium-containing polymer or phosphonium-containing compound of the present invention can be carried out in a one-step reaction from a stable raw material compound (for example, a compound represented by the above general formula (4-1) or (4-2)). is possible, and the phosphonium-containing polymer or phosphonium-containing compound of the present invention can be obtained very easily.

で表される反応を経て得ることができる。
なお、上記式（２）で表される化合物と、上記式（３－１）で表される化合物と、上記式（３－２）で表される化合物から、式（１’）で表される化合物が生成する反応について、想定される反応機構を示しているが、この反応は、１工程で式（１’）で表される化合物を生成させることができるものである。例えば、上記式（３－１）で表される化合物と、上記式（３－２）で表される化合物が同一である場合、通常、上記式（３－１）で表される化合物２当量が、上記式（２）で表される化合物１当量に対して連続して反応し、式（１’）で表される化合物が１工程で一気に生成する。なお、上記式（３－１）で表される化合物と、上記式（３－２）で表される化合物が異なっている場合、この反応は、開始時から３種類すべての原料を用いて１工程で式（１’）で表される化合物を生成させるものであってもよいし、上記式（２）で表される化合物と、上記式（３－１）で表される化合物とを先ず反応させた後、上記式（３－２）で表される化合物を後添加して、上記反応機構で示される順序に沿って２工程で反応させるものであってもよい。
また上記反応式において、Ａは、Ｓ、ＮＲ^６、又は、Ｏを表す。 The method for producing the phosphonium-containing compound of the present invention can be carried out, for example, by the following reaction scheme:

It can be obtained via the reaction represented by the following formula:
In addition, the assumed reaction mechanism for the reaction in which the compound represented by formula (1') is produced from the compound represented by formula (2), the compound represented by formula (3-1), and the compound represented by formula (3-2) is shown, and this reaction can produce the compound represented by formula (1') in one step. For example, when the compound represented by formula (3-1) and the compound represented by formula (3-2) are the same, usually, 2 equivalents of the compound represented by formula (3-1) react with 1 equivalent of the compound represented by formula (2) in succession, and the compound represented by formula (1') is produced all at once in one step. In addition, when the compound represented by the above formula (3-1) and the compound represented by the above formula (3-2) are different, this reaction may be a one-step reaction in which all three kinds of raw materials are used from the start to produce the compound represented by formula (1'), or a two-step reaction in which the compound represented by the above formula (2) and the compound represented by the above formula (3-1) are first reacted, and then the compound represented by the above formula (3-2) is added later, in accordance with the sequence shown in the above reaction mechanism.
In the above reaction formula, A represents S, NR ⁶ , or O.

で表される反応を経て得ることもできる。 The method for producing the phosphonium-containing compound of the present invention includes, for example, the following reaction formula:

It can also be obtained through the reaction represented by

The method for producing the phosphonium-containing polymer of the present invention is not particularly limited, but it can be obtained, for example, by the following reaction.
First, among the phosphine compounds (2), a compound having at least two halogen atoms and a dihydroxy compound (6) are reacted to form a polymer. This reaction can be carried out in an organic solvent such as N-methyl-2-pyrrolidone (NMP) in the presence of a base such as potassium carbonate. The reaction temperature is preferably 100 to 200°C, for example. Preferably, the reaction time is, for example, 6 to 48 hours. The pressure conditions are not particularly limited, and may be normal pressure, increased pressure, or reduced pressure.

The phosphonium-containing polymer of the present invention can be obtained by reacting the polymer obtained by the above reaction with aligne. This reaction can be carried out in an organic solvent such as tetrahydrofuran (THF) or acetonitrile. The reaction temperature is preferably -10 to 40°C, for example. The reaction time is preferably, for example, 10 to 48 hours. The pressure conditions are not particularly limited, and may be normal pressure, increased pressure, or reduced pressure.

で表される反応を経て得ることができる。
なお、上記式（７）で表される化合物と、上記式（３－１）で表される化合物と、上記式（３－２）で表される化合物から、式（８）で表される化合物が生成する反応について、想定される反応機構を示しているが、この反応は、１工程で式（８）で表される化合物を生成させることができるものである。例えば、上記式（３－１）で表される化合物と、上記式（３－２）で表される化合物が同一である場合、通常、上記式（３－１）で表される化合物２当量が、上記式（７）で表される化合物１当量に対して連続して反応し、式（８）で表される化合物が１工程で一気に生成する。なお、上記式（３－１）で表される化合物と、上記式（３－２）で表される化合物が異なっている場合、この反応は、開始時から３種類すべての原料を用いて１工程で式（８）で表される化合物を生成させるものであってもよいし、上記式（７）で表される化合物と、上記式（３－１）で表される化合物とを先ず反応させた後、上記式（３－２）で表される化合物を後添加して、上記反応機構で示される順序に沿って２工程で反応させるものであってもよい。
また上記反応式において、Ｙ^１、Ｙ^２は、ハロゲン原子を表す。Ｚは、有機基を表し、好ましくは炭化水素基であり、より好ましくは、炭素数１～１８の脂肪族飽和炭化水素基（アルキル基）、脂肪族不飽和炭化水素基（アルケニル基等）、炭素数６～１８の芳香族炭化水素基（アリール基）、炭素数７～１８のアラルキル基である。Ａは、Ｓ、ＮＲ^６、又は、Ｏを表す。 The method for producing the phosphonium-containing polymer of the present invention includes, for example, the following reaction formula:

It can be obtained through the reaction shown below.
Furthermore, from the compound represented by the above formula (7), the compound represented by the above formula (3-1), and the compound represented by the above formula (3-2), the compound represented by the formula (8) The assumed reaction mechanism for the reaction that produces the compound is shown, and this reaction can produce the compound represented by formula (8) in one step. For example, when the compound represented by the above formula (3-1) and the compound represented by the above formula (3-2) are the same, usually 2 equivalents of the compound represented by the above formula (3-1) reacts continuously with one equivalent of the compound represented by the above formula (7), and the compound represented by the formula (8) is produced all at once in one step. In addition, when the compound represented by the above formula (3-1) and the compound represented by the above formula (3-2) are different, this reaction is carried out using all three types of raw materials from the beginning. The compound represented by the formula (8) may be produced in the step, or the compound represented by the above formula (7) and the compound represented by the above formula (3-1) may be first reacted. After this, the compound represented by the above formula (3-2) may be added later, and the reaction may be carried out in two steps according to the order shown in the above reaction mechanism.
Moreover, in the above reaction formula, Y ¹ and Y ² represent halogen atoms. Z represents an organic group, preferably a hydrocarbon group, more preferably an aliphatic saturated hydrocarbon group (alkyl group) having 1 to 18 carbon atoms, an aliphatic unsaturated hydrocarbon group (alkenyl group, etc.), These are an aromatic hydrocarbon group (aryl group) having 6 to 18 carbon atoms, and an aralkyl group having 7 to 18 carbon atoms. A represents S, NR ⁶ or O.

で表される反応を経て得ることもできる。
なお、上記反応式において、Ｙ^１、Ｙ^２、Ｚは、上述した通りである。 The method for producing the phosphonium-containing polymer of the present invention includes, for example, the following reaction formula:

It can also be obtained through the reaction represented by
In addition, in the above reaction formula, Y ¹ , Y ² , and Z are as described above.

<Electrolyte material of the present invention>
The present invention is also an electrolyte material characterized by containing the phosphonium-containing polymer of the present invention.
The electrolyte material of the present invention may contain, in addition to the phosphonium-containing polymer of the present invention, other components such as monomers that are raw materials thereof, a solvent, and the like.
Examples of the solvent include alcohols such as methanol, ethanol, propanol, and butanol; alkylene glycol monoalkyl ethers; halogenated solvents such as dichloromethane, chloroform, 1,2-dichloroethane, chlorobenzene, and dichlorobenzene; dimethylformamide, dimethylacetamide, N -Methyl-2-pyrrolidone (NMP), dimethyl sulfoxide, γ-butyrolactone, etc., and one or more of these can be used.
The electrolyte material of the present invention is useful as a solid polymer electrolyte membrane for water electrolysis and alkaline fuel cells.

<Anion exchange membrane of the present invention>
The present invention is also an anion exchange membrane characterized by containing the phosphonium-containing polymer of the present invention.
The anion exchange membrane of the present invention is useful as a solid polymer electrolyte membrane for water electrolysis and alkaline fuel cells.

The anion exchange membrane of the present invention preferably has an average thickness of 10 to 1000 μm. The average film thickness is more preferably 20 to 500 μm.
The thickness of the anion exchange membrane of the present invention can be measured with a micrometer.

The method for producing the anion exchange membrane of the present invention is not particularly limited as long as the membrane is formed, and includes a method of dissolving the phosphonium-containing polymer of the present invention in a solvent and pouring it onto a flat surface to evaporate the organic solvent; A method of rolling the electrolyte material of the invention into a film shape, a method of rolling it with a flat plate press or the like and forming it into a film shape, a method of molding it into a film shape such as an injection molding method, an extrusion molding method, a casting method, etc. can be used. These molding methods may be used alone or in combination of two or more.
As described above, the manufacturing method may include, in addition to the step of forming the electrolyte material into a membrane, the step of drying the membrane. The drying temperature may be set appropriately, but it can be carried out at 60°C to 160°C.

The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these Examples. In addition, "%" shall mean "mol%."

(Synthesis of compounds)
<Synthesis of benzyne precursor>
Synthesis Example 1: Synthesis of Benzyne Precursor 1 2-bromophenol (10.4g, 60mmol) and 1,1,1,3,3,3-hexamethyldisilazane (25.3mL, 120mmol, 2.0eq.) was dissolved in THF (20 ml) and stirred under heating and reflux for 3 hours. After the solvent was distilled off under reduced pressure, the formation of a silyl protected product was confirmed by ¹ H-NMR. The product was dissolved in THF (78 mL) and cooled to -78°C, then n-butyllithium (41.3 mL, 66 mmol, ca. 1.6 M, 1.1 eq.) was slowly added and the mixture was heated at -78°C for 30 minutes. After stirring, trifluoromethanesulfonic anhydride (20.3 g, 72 mmol, 1.2 eq.) was slowly added and stirred at -78°C for 30 minutes. After quenching the reaction by adding saturated sodium hydrogen carbonate, the organic layer was extracted with ethyl acetate. The organic layer was dried over sodium sulfate, filtered, and the solvent was distilled off under reduced pressure. The residue was purified by silica gel chromatography (hexane: ethyl acetate = 40:1) to obtain benzyne precursor 1 (14.9 g, 50 mmol, 83%) as a colorless transparent oil. It was confirmed by NMR that it had the structure shown in the following formula. In addition, TMS means a trimethylsilyl group, and Tf means a trifluoromethanesulfonyl group. The same applies to the following synthesis examples and examples.

The spectral data is shown below.
¹ H-NMR (300 MHz, CDCl ₃ ): δ7.54 (dd, J=7.6, 1.6 Hz, 1H), 7.44 (ddd, J=8.0, 7.6, 2.0 Hz, 1H), 7.38-7.29 (m, 2H), 0.304 (s, 9H) ppm

Synthesis Example 2: Synthesis of Benzyne Precursor 2 2,6-dimethylphenol (6.11 g, 50 mmol) was dissolved in carbon disulfide (180 ml), and after cooling to 0°C, N-bromosuccinimide (9.97 g, 56 mmol) was dissolved. , 1.1 eq.) was slowly added, and the mixture was stirred at room temperature for 3 hours. After distilling off the solvent under reduced pressure, it was purified by silica gel chromatography (hexane: ethyl acetate = 40:1) to obtain 2-bromo-3,6-dimethylphenol (6.09 g, 30 mmol, 61%) as a colorless oil. obtained as. 2-bromo-3,6-dimethylphenol (1.30 g, 6.5 mmol) and 1,1,1,3,3,3-hexamethyldisilazane (1.15 mL) were prepared in the same manner as in the synthesis of benzyne precursor 1. , 7.1 mmol, 1.1 eq.) was dissolved in THF (16 ml) and stirred under heating under reflux for 3 hours. After the solvent was distilled off under reduced pressure, the formation of a silyl protected product was confirmed by ¹ H-NMR. The product was dissolved in THF (20 mL) and cooled to -78°C, and then n-butyllithium (4.40 mL, 7.1 mmol, ca. 1.6 M, 1.1 eq.) and trifluoromethanesulfonic anhydride ( 2.20 g, 7.8 mmol, 1.2 eq.) was reacted and purified by silica gel chromatography (hexane: ethyl acetate = 40:1) to obtain benzyne precursor 2 (1.04 g, 3.2 mmol, 49%). was obtained as a colorless transparent oil. It was confirmed by NMR that it had the structure shown in the following formula. The spectral data is shown below.
¹ H-NMR (300 MHz, CDCl ₃ ): δ = 7.03 (d, J = 7.5 Hz, 1 H), 6.91 (d, J = 7.5 Hz, 1 H), 2.33 (s, 3 H ), 1.97 (s, 3H), 0.24 (s, 9H) ppm

<Synthesis of phosphonium salts>
Example 1: Synthesis of phosphonium-containing compound 1 Chlorodiphenylphosphine (1.10 g, 5.0 mmol) was dissolved in THF (20 ml), cooled to -78°C, and then 2-methylphenylmagnesium bromide (4.40 mL, 5 .5 mmol, ca. 1.25 M, 1.1 eq.) was slowly added and stirred at room temperature for 24 hours. The reaction was stopped by adding an appropriate amount of ammonium chloride water, and the mixture was extracted with ethyl acetate. The organic layer was dried over magnesium sulfate, filtered, and the solvent was distilled off under reduced pressure. After recrystallizing from ethanol, the product was purified by silica gel chromatography (hexane) to obtain diphenyl-o-tolylphosphine (0.845 g, 3.1 mmol, 61%) as a white powder. Cesium fluoride (0.277 g, 1.8 mmol, 6.0 eq.) was placed in a flask, and the flask was evacuated and heated with a heat gun for about 5 minutes to remove the water content. After purging with argon gas, diphenyl-o-tolylphosphine (0.0828 g, 0.30 mmol) synthesized above was added and dissolved in acetonitrile (3 ml). After cooling to 0° C., benzyne precursor 1 (0.224 g, 0.75 mmol, 2.5 eq.) was slowly added, and the mixture was stirred at room temperature for 24 hours. An appropriate amount of sodium chloride water was added, and the mixture was extracted with ethyl acetate. The organic layer was dried over magnesium sulfate, filtered, and the solvent was distilled off under reduced pressure. The residue was purified by silica gel chromatography ((i) dichloromethane, (ii) dichloromethane:methanol = 20:1) to obtain phosphonium-containing compound 1 (0.0766 g, 0.15 mmol, 51%) as a pale orange powder. It was confirmed by NMR that it had the structure shown in the following formula. The spectral data is shown below.
^1H -NMR (300MHz, CDCl ₃ ) δ = 7.86-7.91 (m, 3H), 7.75-7.81 (m, 7H), 7.62-7.68 (m, 7H) 7.47-7.49 (m, 1H), 7.15-7.19 (m, 1H) ppm; ³¹ P-NMR (121 MHz, CDCl ₃ ) δ = 22.5 ppm

Example 2: Synthesis of phosphonium-containing compound 2 Dichlorophenylphosphine (0.896 g, 5.0 mmol), o-tolylmagnesium bromide (8.40 mL, 11 mmol, ca. 1.25 M, 2. 1 eq.) in THF (20 ml), recrystallized with ethanol, and purified with silica gel chromatography (hexane) to synthesize phenyl di-o-tolylphosphine (0.679 g, 2.3 mmol, 47%). . Furthermore, phenyldi-o-tolylphosphine (0.0871 g, 0.30 mmol), cesium fluoride (0.274 g, 1.8 mmol, 6.0 eq.), and benzyne precursor 1 (0 .224g, 0.75mmol, 2.5eq.) and acetonitrile (3ml) were reacted and purified by silica gel chromatography to obtain phosphonium-containing compound 2 (0.109g, 0.21mmol, 70%) as a pale orange powder. Ta. It was confirmed by NMR that it had the structure shown in the following formula. The spectral data is shown below.

¹ H-NMR (300 MHz, CDCl ₃ ) δ = 7.75-7.89 (m, 8H), 7.51-7.68 (m, 8H), 7.41 (dd, J = 6.9, 14.4 Hz, 2H) 2.00 (s, 6H) ppm; ³¹ P-NMR (121 MHz, CDCl ₃ ) δ = 22.5 ppm

Example 3: Synthesis of phosphonium-containing compound 3 Tris(o-tolyl)phosphine (0.0915 g, 0.30 mmol) and cesium fluoride (0.273 g, 1.8 mmol, 6.0 eq) were prepared in the same manner as in Example 1. ), benzyne precursor 1 (0.224 g, 0.75 mmol, 2.5 eq.), and acetonitrile (3 ml) were reacted and purified by silica gel chromatography to obtain phosphonium-containing compound 3 (0.111 g, 0.21 mmol, 70%) was obtained as a pale orange powder. It was confirmed by NMR that it had the structure shown in the following formula. The spectral data is shown below.

¹ H-NMR (300 MHz, CDCl ₃ ) δ = 7.79-7.81 (m, 6H), 7.46-7.55 (m, 11H), 1.88 (s, 9H) ppm; ³¹ P -NMR (121 MHz, CDCl ₃ ) δ = 22.4 ppm

Example 4: Synthesis of phosphonium-containing compound 4 Tris(o-tolyl)phosphine (0.0904 g, 0.3 mmol) and cesium fluoride (0.278 g, 1.8 mmol, 6.0 eq) were prepared in the same manner as in Example 1. ), benzyne precursor 2 (0.242 g, 0.75 mmol, 2.5 eq.), and acetonitrile (3 ml) were reacted and purified by silica gel chromatography to obtain phosphonium-containing compound 4 (0.152 g, 0.27 mmol, 91%) was obtained as a pale orange powder. It was confirmed by NMR that it had the structure shown in the following formula. The spectral data is shown below.

^1H -NMR (300MHz, _CDCl3 ): δ = 7.70-7.78 (m, 3H), 7.56-7.63 (m, 9H), 7.32-7.46 (m, 3H), 2.37 (s, 3H, _CH3 ), 1.95 (s, 3H, _CH3 ), 1.92 (s, 3H, _CH3 ), 1.90 (s, 3H, _CH3 ), 1.85 (s, 3H, _CH3 ) ppm; ^31P -NMR (121MHz, _CDCl3 ): δ = 22.5 ppm.

Example 5: Synthesis of phosphonium-containing compound 5 Diphenyl-o-tolylphosphine (0.552 g, 2.0 mmol), sulfur powder (64.2 mg, 2.0 mmol, 1.0 eq), and toluene (20 mL) were placed in a flask. After reacting for 24 hours under heating and reflux, the solvent was distilled off under reduced pressure. Purification by silica gel chromatography (hexane:dichloromethane=1:1) gave diphenyl-o-tolylphosphine sulfide (0.559 g, 1.8 mmol, 91%) as a white powder. Cesium fluoride (0.278 g, 1.8 mmol, 6.0 eq.) was placed in a flask, and the flask was evacuated and heated with a heat gun for about 5 minutes to remove the water content. After purging with argon gas, diphenyl-o-tolylphosphine sulfide (0.0930 g, 0.30 mmol) was added and dissolved in acetonitrile (5 ml). The mixture was cooled to 0° C., and benzyne precursor 1 (0.269 g, 0.90 mmol, 3.0 eq.) dissolved in acetonitrile (10 mL) was slowly added, and the mixture was heated to room temperature and stirred for 24 hours. After confirming the completion of the reaction by ³¹ P-NMR, inorganic salts were removed by celite filtration, and the solvent was distilled off under reduced pressure. The residue was purified by silica gel chromatography ((i) dichloromethane, (ii) dichloromethane:methanol = 20:1) to obtain phosphonium-containing compound 5 (0.180 g, 0.29 mmol, 98%) as a pale orange powder. It was confirmed by NMR that it had the structure shown in the following formula. The spectral data is shown below.

^1H -NMR (300MHz, CDCl ₃ ): δ = 7.51-7.78 (m, 19H), 7.22-7.29 (m, 2H), 6.85-6.87 (m, 2H ), 2.04 (s, 3H) ppm; ³¹ P-NMR (121 MHz, CDCl ₃ ): δ=22.8 ppm.

Example 6: Synthesis of phosphonium-containing compound 6 Phenyl di-o-tolylphosphine (0.435 g, 1.5 mmol), sulfur powder (48.0 mg, 1.5 mmol, 1.0 eq), Toluene (15 mL) was reacted and purified by silica gel chromatography (hexane: dichloromethane = 1:1) to obtain phenyl di-o-tolylphosphine sulfide (0.477 g, 1.5 mmol, 98%) as a white powder. Furthermore, phenyldi-o-tolylphosphine sulfide (0.0961 g, 0.30 mmol), cesium fluoride (0.273 g, 1.8 mmol, 6.0 eq.), and benzyne precursor 1 ( 0.266 g, 0.90 mmol, 3.0 eq.) and acetonitrile (15 mL), and purified by silica gel chromatography ((i) dichloromethane, (ii) dichloromethane:methanol = 20:1) to obtain phosphonium-containing compound 6. (0.186 g, 0.30 mmol, 99%) was obtained as a pale orange powder. It was confirmed by NMR that it had the structure shown in the following formula. The spectral data is shown below.

^1H -NMR (300MHz, CDCl ₃ ): δ = 7.67-7.75 (m, 13H), 7.26-7.52 (m, 6H), 7.24-7.26 (m, 1H) ), 6.89 (d, J = 6.6 Hz, 2H), 1.99 (s, 6H) ppm; ³¹ P-NMR (121 MHz, CDCl ₃ ): δ = 22.9 ppm.

Example 7: Synthesis of phosphonium-containing compound 7 Tris(o-tolyl)phosphine (0.761 g, 2.5 mmol) and sulfur powder (85.0 mg, 2.6 mmol, 1.1 eq) were prepared in the same manner as in Example 5. , toluene (25 mL) was reacted and purified by silica gel chromatography (hexane: dichloromethane = 2:1) to obtain tris(o-tolyl)phosphine sulfide (0.696 g, 2.1 mmol, 83%) as a white powder. Ta. Furthermore, tris(o-tolyl)phosphine sulfide (0.100 g, 0.30 mmol), cesium fluoride (0.276 g, 1.8 mmol, 6.0 eq.), and benzyne precursor 1 were added in the same manner as in Example 5. (0.266 g, 0.90 mmol, 3.0 eq.) and acetonitrile (15 mL) were reacted and purified by silica gel chromatography ((i) dichloromethane, (ii) dichloromethane:methanol = 20:1) to obtain a phosphonium-containing compound. 7 (0.153 g, 0.24 mmol, 80%) was obtained as a pale orange powder. It was confirmed by NMR that it had the structure shown in the following formula. The spectral data is shown below.

^1H -NMR (300MHz, _CDCl3 ): δ = 7.46-7.79 (m, 17H), 7.27-7.44 (m, 2H), 6.93-6.95 (d, J = 3.6Hz, 2H), 2.01 (s, 3H), 1.96 (s, 3H), 1.92 (s, 3H) ppm; ^31P -NMR (121MHz, _CDCl3 ): δ = 23.4 ppm.

Example 8: Synthesis of phosphonium-containing compound 8 Tris(o-tolyl)phosphine sulfide (0.101 g, 0.30 mmol), cesium fluoride (0.273 g, 1.8 mmol, 6.0 g) were prepared in the same manner as in Example 5. 0 eq.), benzyne precursor 2 (0.589 g, 1.8 mmol, 6.0 eq.), and acetonitrile (15 mL) were reacted, and silica gel chromatography ((i) dichloromethane, (ii) dichloromethane:methanol = 20:1 ) to obtain phosphonium-containing compound 8 (0.169 g, 0.24 mmol, 81%) as a pale orange powder. It was confirmed by NMR that it had the structure shown in the following formula. The spectral data is shown below.

¹ H-NMR (300 MHz, CDCl ₃ ) δ = 7.49-7.84 (m, 12H), 6.98-7.01 (m, 3H), 6.68 (s, 2H), 2.35 (s, 3H), 2.33 (s, 3H), 2.24 (s, 3H), 1.97 (s, 3H), 1.87 (s, 3H), 1.75 (s, 3H) , 1.70 (s, 3H) ppm; ³¹ P-NMR (121 MHz, CDCl ₃ ) δ = 19.3 ppm.

Comparative Example 1: Synthesis of Phosphonium-Containing Compound 9 Chemical stability was evaluated using commercially available tetraphenylphosphonium bromide (phosphonium-containing compound 9). The purchased reagents were used as they were without any particular purification.

Comparative Example 2: Synthesis of phosphonium-containing compound 10 Triphenylphosphine (2.62 g, 10 mmol), sulfur powder (0.323 g, 10 mmol, 1.0 eq), and toluene (100 mL) were placed in a flask and heated under reflux for 24 hours. After that, the solvent was distilled off under reduced pressure. The residue was purified by silica gel chromatography (hexane:dichloromethane=1:1) to obtain triphenylphosphine sulfide (2.72 g, 9.2 mmol, 92%) as a white powder. Cesium fluoride (0.269 g, 1.8 mmol, 6.0 eq.) was placed in a flask, and the flask was evacuated and heated with a heat gun for about 5 minutes to remove the water content. After purging with argon gas, triphenylphosphine sulfide (0.0881 g, 0.30 mmol) was added and dissolved in acetonitrile (5 ml). The mixture was cooled to 0° C., and benzyne precursor 1 (0.269 g, 0.90 mmol, 3.0 eq.) dissolved in acetonitrile (10 mL) was slowly added, and the mixture was heated to room temperature and stirred for 24 hours. After confirming the completion of the reaction by ³¹ P-NMR, inorganic salts were removed by celite filtration, and the solvent was distilled off under reduced pressure. The residue was purified by silica gel chromatography ((i) dichloromethane, (ii) dichloromethane:methanol = 20:1) to obtain phosphonium-containing compound 10 (0.114 g, 0.19 mmol, 64%) as a white powder. It was confirmed by NMR that it had the structure shown in the following formula. The spectral data is shown below.

^1H -NMR (300MHz, CDCl ₃ ): δ = 7.81-7.84 (m, 3H), 7.65-7.78 (m, 14H), 7.23-7.27 (m, 5H ), 6.90 (d, J = 7.6 Hz, 2H) ppm; ³¹ P-NMR (121 MHz, CDCl ₃ ): δ = 22.6 ppm

Example 9: Synthesis of phosphonium-containing compound 11 2-bromotoluene (6.85 g, 40 mmol) was dissolved in THF (60 ml), cooled to -78°C, and then n-BuLi (27.5 mL, 44 mmol, 1.1 eq ) was slowly added dropwise and stirred at -78°C for 30 minutes. This reaction solution was slowly added dropwise to a solution of zinc chloride (6.55 g, 48 mmol, 1.2 eq.) and THF (60 mL) at -78°C using a cannula, and the mixture was stirred at -78°C for 2 hours. This reaction solution was slowly added dropwise to a solution of phosphorus trichloride (4.19 mL, 48 mmol, 1.2 eq.) and THF (80 mL) at -78°C using a cannula, and the mixture was heated to room temperature and stirred for 18 hours. It was confirmed by ³¹ P-NMR that a monosubstituted product was selectively produced, and the solvent was distilled off under reduced pressure. After adding distilled hexane (50 mL) to extract the target product, the solvent was distilled off under reduced pressure, THF (120 mL) was added, and the mixture was cooled to -78°C. 4-Fluoro-2-methylphenylmagnesium bromide (70.4 mL, 88 mmol, ca. 1.25 M, 2.2 eq.) was slowly added, the temperature was raised to room temperature, and the mixture was stirred for 24 hours. It was confirmed by ³¹ P-NMR that the target product had been produced, and an appropriate amount of ammonium chloride water was added to stop the reaction, followed by extraction with ethyl acetate. The organic layer was dried over magnesium sulfate, filtered, and the solvent was distilled off under reduced pressure. Purification was performed by silica gel chromatography (hexane) to obtain Intermediate 1 (4.77 g, 14 mmol, 35%) as a white powder.

Intermediate 1 (0.306 g, 0.90 mmol), sulfur powder (32.9 mg, 0.99 mmol, 1.1 eq), and toluene (9 mL) were reacted in the same manner as in Example 5, and purified by silica gel chromatography (hexane:dichloromethane=2:1) to obtain intermediate 2 (0.259 g, 0.70 mmol, 77%) as a white powder.

Intermediate 2 (0.372 g, 1.0 mmol), p-cresol (0.270 g, 2.5 mmol, 2.5 eq.), and potassium carbonate (0.415 g, 3.0 mmol, 3.0 eq.) were dissolved in NMP (10 ml), stirred at 130° C. for 1 hour, and then heated to 160° C. and reacted for 14 hours. After the reaction was completed, the solution was cooled to room temperature, water was added, and extracted with hexane/ethyl acetate = 4:1. Then, it was washed three times with water, and the organic layer was dried over magnesium sulfate, filtered, and the solvent was distilled off under reduced pressure. It was purified by silica gel chromatography (hexane/dichloromethane = 4:1) to obtain intermediate 3 (0.281 g, 0.51 mmol, 51%) as a white powder.
In the same manner as in Example 5, intermediate 3 (0.165 g, 0.30 mmol), cesium fluoride (0.272 g, 1.8 mmol, 6.0 eq.), benzyne precursor 1 (0.267 g, 0.6 mmol, 3.0 eq.), and acetonitrile (15 mL) were reacted, and the mixture was purified by silica gel chromatography ((i) dichloromethane, (ii) dichloromethane:methanol=20:1) to obtain phosphonium-containing compound 11 (0.235 g, 0.28 mmol, 92%) as a pale orange powder. The structure shown in the following formula was confirmed by NMR. The spectrum data is shown below.

¹ H-NMR (300 MHz, CDCl ₃ ): δ=7.34-7.82 (m, 8H), 7.18-7.28 (m, 7H), 6.87-7.02 (m, 12H), 2.37 (s, 6H), 1.81-2.02 (m, 9H) ppm; ³¹ P-NMR (121 MHz, CDCl ₃ ): δ=21.8-22.0 ppm.

<Synthesis of phosphonium-containing polymer>
Example 10: Synthesis of phosphonium-containing polymer 1 Intermediate 2 (0.373 g, 1.0 mmol), bisphenol A (0.373 g, 1.0 mmol, 1.0 eq.), potassium carbonate were prepared in the same manner as in Example 9. (0.194 g, 1.4 mmol, 1.4 eq.) and NMP (1.1 ml) were reacted to obtain Intermediate 4 (0.523 g, 0.93 mmol, 93%) as a white solid.

Cesium fluoride (2.92 g, 19 mmol, 24 eq.) was placed in a flask, and the flask was evacuated and heated with a heat gun for about 5 minutes to remove the water content. After purging with argon gas, Intermediate 4 (0.449 g, 0.80 mmol) was added and dissolved in THF (72 mL) and acetonitrile (8 ml). The mixture was cooled to 0° C., and benzyne precursor 1 (2.88 g, 9.6 mmol, 12 eq.) was slowly added thereto, heated to room temperature, and stirred for 24 hours. After confirming the completion of the reaction by ³¹ P-NMR, inorganic salts were removed by celite filtration, and the solvent was distilled off under reduced pressure. The residue was dissolved in a small amount of dichloromethane and slowly added dropwise to ethyl acetate. After washing with ethyl acetate and deionized water to collect the solid, it was dried under reduced pressure at 60° C. for 2 hours to obtain phosphonium-containing polymer 1 (0.425 g, 0.49 mmol, 62%) as a pale orange solid. When analyzed by gel permeation chromatography, the number average molecular weight of the obtained polymer was about 12,000, and the weight average molecular weight was about 28,000. It was confirmed by NMR that it had the structure shown in the following formula. The spectral data is shown below.

^1H -NMR (300MHz, CDCl ₃ ) δ = 7.32-7.84 (m, 16H), 6.76-7.09 (m, 11H), 1.75-2.00 (m, 9H) , 1.58-1.72 (s, 6H) ppm; ³¹ P-NMR (121 MHz, CDCl ₃ ) δ = 21.6-21.8 ppm

Example 11: Synthesis of Phosphonium-Containing Polymer 2 Intermediate 2 (0.111 g, 0.30 mmol), 9,9-bis(4-hydroxyphenyl)fluorene (0.105 g, 0.1 g, 30 mmol, 1.0 eq.), potassium carbonate (0.0572 g, 0.42 mmol, 1.4 eq.), and NMP (0.43 ml) were reacted to produce intermediate 5 (0.171 g, 0.25 mmol, 83%). was obtained as a white solid.

Intermediate 5 (0.547 g, 0.80 mmol), benzyne precursor 1 (2.87 g, 9.6 mmol, 12 eq.), and cesium fluoride (2.91 g, 19 mmol, 24 eq.) were prepared in the same manner as in Example 10. ), THF (72 mL), and acetonitrile (8 ml) were reacted to obtain phosphonium-containing polymer 2 (0.439 g, 0.44 mmol, 56%) as a pale orange solid. When analyzed by gel permeation chromatography, the number average molecular weight of the obtained polymer was about 7,000, and the weight average molecular weight was about 15,000. It was confirmed by NMR that it had the structure shown in the following formula. The spectral data is shown below.

^1H -NMR (300MHz, CDCl ₃ ) δ = 7.08-7.82 (m, 24H), 6.63-7.02 (m, 11H), 1.65-2.05 (m, 9H) ppm; ³¹ P-NMR (121 MHz, CDCl ₃ ) δ = 21.6-21.8 ppm

(Evaluation of chemical stability)
<Chemical stability evaluation of phosphonium-containing compounds (stability of ion exchange groups)>
The chemical stability of the ion exchange group in the phosphonium-containing compound against bases was evaluated by the following method based on ³¹ P-NMR spectrometry. Potassium hydroxide was dissolved in a mixed solvent of heavy methanol/heavy water = 5/1. Potassium hydroxide solutions were prepared in three concentrations: 0.1M, 1M, and 6M. Each phosphonium-containing compound was dissolved in the above potassium hydroxide solution to prepare a sample solution. In addition, a phosphoric acid solution as a reference substance was placed in a capillary tube and sealed, and this was used as an external standard. An external standard tube was inserted into the NMR tube containing each phosphonium-containing compound solution, and ³¹ P-NMR measurement was performed at room temperature. Next, each phosphonium-containing compound solution was heated at 80° C. in an oil bath, and after a predetermined period of time, ³¹ P-NMR measurement was performed. The residual rate of each sample was calculated using the following formula, and the decomposition behavior was tracked.
Residual rate = {(Peak area of phosphonium-containing compound after heating) / (peak area of phosphoric acid)} / {(peak area of phosphonium-containing compound before heating) / (peak area of phosphoric acid)} x 100 (% )

Different potassium hydroxide concentrations were used depending on the durability of each phosphonium-containing compound, and the ranking of the durability of each compound was compared. The results of evaluation in 0.1 M potassium hydroxide are shown in Table 1, the results of evaluation in 1 M potassium hydroxide in Table 2, and the results of evaluation in 6 M potassium hydroxide in Table 3.

As shown in Tables 1 to 3, it can be seen that the durability under basic conditions is greatly improved by introducing a substituent at the ortho position in the tetraphenylphosphonium-containing compound. Furthermore, it can be seen that the order of durability is not greatly influenced by the presence or absence of phenyl sulfide groups.

<Chemical stability evaluation of phosphonium-containing polymers (stability of ether bonds)>
The influence of ether bonds in the phosphonium-containing polymer on chemical stability was evaluated by the following method using phosphonium-containing compound 11 as a model compound. Phosphonium-containing compound 11 was left in 1M KOH at 80° C. for 30 days, and ³¹ P-NMR measurements were performed before, after 15 days, and after 30 days. The NMR spectrum is shown in FIG. It can be seen that the integrated area of the peak assigned to phosphonium-containing compound 11 does not change at all, indicating that no decomposition has occurred. From the above, it can be said that the ether bonds contained in the phosphonium-containing polymer hardly deteriorate under basic conditions, suggesting that the polyether-based electrolyte membrane designed this time has extremely high chemical stability.

(Creation and physical property evaluation of anion exchange membrane)
<Formation of anion exchange membrane>
The membrane was created by drop casting. A 20% by weight DMF solution of the phosphonium-containing polymer was dropped onto a 2.5 cm x 2.5 cm glass substrate, heated in an oven at 60° C. under normal pressure for 24 hours, and then vacuum dried for 24 hours. Thereafter, the film was peeled off from the glass substrate, immersed in a 1M NaOH solution at room temperature for 24 hours, washed with deionized water, and then various measurements were performed.

<Thermal stability evaluation>
The thermal stability of the anion exchange membrane was measured by thermogravimetry (TGA). Measurements were performed in the temperature range of 40 to 800°C to determine the thermal decomposition temperature (Td: 5% by weight thermal decomposition temperature). The TGA curve is shown in FIG. 2, and the Td is shown in Table 4.

<Water content (Water Uptake: WU)>
The sample was immersed in deionized water for 24 hours, the surface was dried with a paper towel, and the wet weight (Mw) was measured. Thereafter, vacuum drying was performed at 60° C. for 24 hours, and the dry weight (Md) was measured. The water content (WU) was calculated by substituting the measured Mw and Md into the following formula. The results are shown in Table 4.

WU (%) = (Mw - Md) / Md x 100%
Md: Dry weight Mw: Wet weight

<Ion Exchange Capacity (IEC) measurement>
Ion exchange capacity refers to the amount of counter anions that can be taken up by an anion exchange membrane, and is usually measured in terms of the hydroxy ions that are taken in. The higher the IEC, the lower the membrane resistance relatively, and high power generation efficiency is expected in devices such as fuel cells and water electrolyzers.
IEC was measured as follows. The anion exchange membrane was immersed in a 1M aqueous sodium hydroxide solution at room temperature for 48 hours, gently removed with a paper towel, and then immersed in a 0.025M HCl solution for 24 hours. Several drops of BTB solution was added as an indicator, and titration was performed with a 0.025M aqueous sodium hydroxide solution. IEC was calculated using the following formula.
IEC [mmol/g] = (V _HCl ×C _HCl -V _NaOH ×C _NaOH )/M
V _HCl : Volume of hydrochloric acid C _HCl : Concentration of hydrochloric acid V _NaOH : Volume of sodium hydroxide C _NaOH : Concentration of sodium hydroxide M: Weight of sample

Table 4 shows the calculated ion exchange capacity values.

From the above results, the membranes of the examples of the present invention can achieve sufficient anion conductivity while having excellent stability.

Claims (5)

A phosphonium-containing polymer,
The polymer has the following general formula (1);

(In the formula, R ¹ to R ⁴ are the same or different and represent a hydrogen atom, a substituent, or a direct bond with another structure possessed by the polymer, and the substituent is a monovalent substituent or a divalent substituent. The monovalent substituent is a monovalent organic group, an amino group, or a halogen atom, and the divalent substituent is a monovalent organic group or an amino group further containing a hydrogen atom. is a group with a structure in which one is eliminated, an oxygen atom, or a sulfur atom. At least one of R ¹ to R ⁴ is a direct bond with another structure possessed by the polymer, or the direct bond is At least one of R ¹ to R ⁴ is a substituent at the ortho position, and is a hydrocarbon group , a hydrocarbon group via an oxygen atom, or a halogen atom. Each of R ¹ to R ⁴ may be bonded to a ring structure in plural numbers, or may be bonded to ^a plurality of divalent substituents to further form a ring structure . represents an anion.) has a structure represented by
A homopolymer having a cation structure in the main chain, a copolymer having the cation structure and another structure (structural unit) in the main chain, or a cation in the structure represented by general formula (1) It is a polymer that has a structure in its side chain,
A phosphonium-containing polymer characterized in that another structure in the copolymer polymer, a main chain structure in a polymer having a cation structure in a side chain, consists of a structural unit containing an aromatic ring . The following general formula (1):

(wherein R ¹ to R ⁴ are the same or different and represent a hydrogen atom or a substituent. The substituent is a monovalent substituent or a divalent substituent, the monovalent substituent is a monovalent organic group, an amino group, or a halogen atom, and the divalent substituent is a group having a structure in which one hydrogen atom has been further removed from a monovalent organic group or an amino group, an oxygen atom, or a sulfur atom. At least four of R ¹ to R ⁴ are substituents at the ortho position and are a hydrocarbon group, a hydrocarbon group via an oxygen atom, a hydrocarbon group via a sulfur atom, or a halogen atom. A plurality of R ¹ to R ⁴ may each be bonded to a ring structure, or a plurality of divalent substituents may be bonded to further form a ring structure. X ^- represents a counter anion. ) A method for producing the phosphonium-containing polymer according to claim 1 or the phosphonium-containing compound according to claim 2, comprising:
A method for producing a phosphonium-containing polymer or a phosphonium-containing compound, characterized in that the production method includes a step of reacting a phosphine compound with aryne. An anion exchange membrane comprising the phosphonium-containing polymer according to claim 1. An electrolyte material comprising the phosphonium-containing polymer according to claim 1.

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