JP7644477B2 - Method for producing phosphate compounds - Google Patents

Description

The present invention relates to a method for producing a phosphate compound. More specifically, the present invention relates to a method for producing a phosphate compound that can produce a high-purity phosphate compound in an extremely simple manner by reacting a phosphoric acid ester with a raw material salt.

Phosphate compounds are used in a wide range of applications, including as surfactants in cleaning compositions, pharmaceuticals, antistatic agents, flame retardants, and additives for secondary batteries (Patent Documents 1 to 4), and a variety of methods for producing phosphate compounds have been developed for each application.

For example, Patent Document 5 discloses a method for producing a phosphoric acid diester salt as a phosphate compound. According to this production method, a phosphoric acid triester is hydrolyzed in the presence of water to produce a phosphoric acid diester, and then the phosphoric acid diester is reacted with a hydroxide such as sodium hydroxide or potassium hydroxide to produce a phosphoric acid diester salt. However, this production method requires a complicated process for separating the unreacted phosphoric acid triester, the alcohol by-produced during the hydrolysis of the phosphoric acid triester, and the reaction solvent used during the reaction of the phosphoric acid triester with the hydroxide. In addition, it is disclosed that the phosphoric acid triester as the starting material can be obtained by reacting, for example, a monohalophosphoric acid diester with a hydroxy compound in the presence of an organic base such as triethylamine, but since a salt of the organic base is by-produced, a process for removing the salt of the organic base is also required. Therefore, the method for producing a phosphoric acid diester salt described in Patent Document 5 has many problems in industrial production in terms of purification and separation processes and waste disposal.

Patent Document 6 discloses a method for producing monohalogenophosphate ester salts or phosphoric acid diester salts. According to this production method, a dihalogenophosphate salt is reacted with an alcohol or the like and an alkali metal base or the like to produce a monohalogenophosphate ester salt or the like. However, the reaction is not easy to control, and a mixture with a phosphoric acid diester salt is obtained as the product. Therefore, isolation and purification of the monohalogenophosphate ester salt or the like is required, but these steps are extremely difficult. On the other hand, when a phosphoric acid diester salt is obtained, the product may contain a monohalophosphate ester salt or an alkali metal salt depending on the reaction substrate. In that case, a step for isolating the phosphoric acid diester salt is required, but the production process becomes complicated. In addition, since an excess amount of alcohol is used as the reaction substrate and solvent, when separating the phosphoric acid diester salt from the product, a large amount of alcohol must be distilled off by vacuum drying, heat drying, or the like.

JP 2007-332355 A JP 2008-231026 A WO2016/158258 publication Japanese Patent Application Publication No. 8-138733 JP 2017-36273 A JP 2019-135215 A

The present invention has been made in consideration of the above problems, and its purpose is to provide a novel method for producing phosphate compounds that is capable of producing high-purity phosphate compounds in an extremely simple manner.

In order to solve the above-mentioned problems, the method for producing a phosphate compound according to the present invention is characterized by including at least a step (I) of reacting a phosphoric acid ester represented by the following chemical formula (A) with a raw material salt represented by the following chemical formula (B) to produce a phosphate compound represented by the following chemical formula (C).

［式中、前記Ｚは、炭素原子又はケイ素原子を表す。前記Ｘ^１及びＸ^２は、それぞれ独立して、ハロゲン原子、炭素数が１～１０の炭化水素基、炭素数が１～１０のアルコキシ基、炭素数が１～１０の範囲であって、ハロゲン原子、ヘテロ原子若しくは不飽和結合の少なくとも何れか１つを有する炭化水素基、又は、炭素数が１～１０の範囲であって、ハロゲン原子、ヘテロ原子若しくは不飽和結合の少なくとも何れか１つを有するアルコキシ基を表す。前記Ｘ^３～Ｘ^５は、それぞれ独立して、水素原子、ハロゲン原子、炭素数が１～１０の炭化水素基、炭素数が１～１０のアルコキシ基、炭素数が１～１０の範囲であって、ハロゲン原子、ヘテロ原子若しくは不飽和結合の少なくとも何れか１つを有する炭化水素基、又は、炭素数が１～１０の範囲であって、ハロゲン原子、ヘテロ原子若しくは不飽和結合の少なくとも何れか１つを有するアルコキシ基を表し、かつ、前記Ｘ^３～Ｘ^５の少なくとも１つは、前記炭素数１～１０の炭化水素基又は前記炭素数１～１０のアルコキシ基の何れかである。］

[In the formula, Z represents a carbon atom or a silicon atom. Each of ^X1 and ^X2 independently represents a halogen atom, a hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a hydrocarbon group having 1 to 10 carbon atoms and having at least one of a halogen atom, a hetero atom, or an unsaturated bond, or an alkoxy group having 1 to 10 carbon atoms and having at least one of a halogen atom, a hetero atom, or an unsaturated bond. X ³ to X ⁵ each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a hydrocarbon group having 1 to 10 carbon atoms and having at least one of a halogen atom, a hetero atom, or an unsaturated bond, or an alkoxy group having 1 to 10 carbon atoms and having at least one of a halogen atom, a hetero atom, or an unsaturated bond, and at least one of X ³ to X ⁵ is either the hydrocarbon group having 1 to 10 carbon atoms or the alkoxy group having 1 to 10 carbon atoms.]

［式中、前記Ｍは、アルカリ金属、アルカリ土類金属、アルミニウム、遷移金属、又はオニウムを表す。前記Ｘ^６は、ハロゲン原子、炭素数１～１０のアルコキシ基、ハロアシルオキシ基、スルホニルオキシ基（－ＳＯ_３Ｙ基：前記Ｙは、ハロゲン原子、炭素数１～１０の炭化水素基、又は、炭素数が１～１０の範囲であって、ハロゲン原子、ヘテロ原子若しくは不飽和結合の少なくとも何れか１つを有する炭化水素基を表す。）を表す。前記ｎは、１～４の自然数を表す。］

[In the formula, M represents an alkali metal, an alkaline earth metal, aluminum, a transition metal, or an onium. ^X6 represents a halogen atom, an alkoxy group having 1 to 10 carbon atoms, a haloacyloxy group, or a sulfonyloxy group (-SO ₃ Y group: Y represents a halogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a hydrocarbon group having 1 to 10 carbon atoms and having at least one of a halogen atom, a hetero atom, or an unsaturated bond). n represents a natural number of 1 to 4.]

［式中、前記Ｍは、前記化学式（Ｂ）と同一のカチオン種を表す。前記Ｘ^１及びＸ^２は、前記化学式（Ａ）と同一の官能基を表す。前記ｎは、前記化学式（Ｂ）と同一の価数を表す。］

[In the formula, M represents the same cationic species as in the chemical formula (B). ^X1 and ^X2 represent the same functional groups as in the chemical formula (A). n represents the same valence as in the chemical formula (B).]

In the above-mentioned configuration, when Z in the above-mentioned chemical formula (A) is a silicon atom, it is preferable to include a step (II) of reacting a phosphoric acid compound represented by the following chemical formula (D) with a silicon compound represented by the following chemical formula (E) to produce a phosphoric acid silyl ester represented by the following chemical formula (F).

［式中、前記Ｍ’は、水素原子、アルカリ金属、アルカリ土類金属、炭素数が１～１０の第１級炭化水素基、炭素数が１～１０の第２級炭化水素基、炭素数が１～１０の範囲であって、ハロゲン原子、ヘテロ原子若しくは不飽和結合の少なくとも何れか１つを有する第１級炭化水素基、又は、炭素数が１～１０の範囲であって、ハロゲン原子、ヘテロ原子若しくは不飽和結合の少なくとも何れか１つを有する第２級炭化水素基を表す。前記Ｘ^１及びＸ^２は、前記化学式（Ａ）と同一の官能基を表す。前記ｎは、前記化学式（Ｂ）と同一の価数を表す。］

[In the formula, M' represents a hydrogen atom, an alkali metal, an alkaline earth metal, a primary hydrocarbon group having 1 to 10 carbon atoms, a secondary hydrocarbon group having 1 to 10 carbon atoms, a primary hydrocarbon group having 1 to 10 carbon atoms and at least one of a halogen atom, a heteroatom, or an unsaturated bond, or a secondary hydrocarbon group having 1 to 10 carbon atoms and at least one of a halogen atom, a heteroatom, or an unsaturated bond. ^X1 and ^X2 represent the same functional group as in the chemical formula (A). n represents the same valence as in the chemical formula (B).]

［式中、前記Ｘ^３～Ｘ^５は、前記化学式（Ａ）と同一の官能基を表す。前記Ｘ^７は脱離基であって、ハロゲン原子、炭素数１～１０のアルコキシ基、ハロアシルオキシ基、又はスルホニルオキシ基（－ＳＯ_３Ｙ基：前記Ｙは、ハロゲン原子、炭素数１～１０の炭化水素基、又は、炭素数が１～１０の範囲であって、ハロゲン原子、ヘテロ原子若しくは不飽和結合の少なくとも何れか１つを有する炭化水素基を表す。）を表す。］

[In the formula, X ³ to X ⁵ represent the same functional groups as in the chemical formula (A). X ⁷ is a leaving group, and represents a halogen atom, an alkoxy group having 1 to 10 carbon atoms, a haloacyloxy group, or a sulfonyloxy group (-SO ₃ Y group: Y represents a halogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a hydrocarbon group having 1 to 10 carbon atoms and having at least one of a halogen atom, a hetero atom, or an unsaturated bond).]

［式中、前記Ｘ^１～Ｘ^５は、前記化学式（Ａ）と同一の官能基を表す。］

[In the formula, X ¹ to X ⁵ represent the same functional groups as those in the chemical formula (A).]

Furthermore, in the above-mentioned configuration, it is preferable that the silicon compound represented by the chemical formula (E) is a by-product produced in the above-mentioned step (I).

In the above-mentioned structure, the phosphoric acid compound is preferably a phosphoric acid diester in which ^X1 and ^X2 in the chemical formula (D) are each independently an alkoxy group having 1 to 10 carbon atoms, and M' is a hydrogen atom.

In the above-mentioned structure, the phosphoric acid compound is preferably a fluorophosphoric acid ester in which one of ^X1 and ^X2 in the chemical formula (D) is a fluorine atom, the other is an alkoxy group having 1 to 10 carbon atoms, and M' is a hydrogen atom.

Furthermore, in the above-mentioned configuration, the phosphoric acid compound is preferably a difluorophosphoric acid in which ^X1 and ^X2 in the chemical formula (D) are fluorine atoms and M' is a hydrogen atom.

In the above-mentioned structure, the silicon compound is preferably a trialkylsilyl halide in which X ³ to X ⁵ in the above-mentioned chemical formula (E) are each independently a hydrocarbon group having 1 to 6 carbon atoms, and X ⁷ is a halogen atom.

In addition, in the above configuration, it is preferable that M in the chemical formula (B) is a lithium atom, a sodium atom, a magnesium atom, 1-methyl-1-propylpyrrolidinium, or 1-ethyl-3-methylimidazolium.

In the above configuration, at least one of steps (I) and (II) can be carried out without a solvent.

In the above configuration, at least one of steps (I) and (II) can be carried out in a non-aqueous solvent.

Furthermore, in the above configuration, it is preferable that the non-aqueous solvent is an aprotic organic solvent.

According to the present invention, by reacting the phosphate ester represented by the chemical formula (A) with the raw material salt represented by the chemical formula (B), the phosphate compound represented by the chemical formula (C) can be produced with high purity in a much simpler and more efficient manner than conventional production methods.

(Method for producing phosphate compounds)
The method for producing a phosphate compound according to the present embodiment will be described below.
The method for producing a phosphate compound of the present embodiment includes at least a step (I) of reacting a phosphate ester represented by chemical formula (A) with a raw material salt represented by chemical formula (B) to produce a phosphate compound represented by chemical formula (C), as shown in the chemical reaction formula below.

The reaction in step (I) is one in which the X ³ X ⁴ X ⁵ Z- group of the phosphate ester is exchanged with M of the starting salt to produce a phosphate compound, and also produces a by-product (E') in an equimolar amount to the phosphate compound.

<Phosphate ester>
The phosphate ester is represented by the following chemical formula (A).

In the above chemical formula (A), Z represents a carbon atom or a silicon atom.

In the chemical formula (A), ^X1 and ^X2 each independently represent a halogen atom, a hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a hydrocarbon group having 1 to 10 carbon atoms and having at least one of a halogen atom, a hetero atom, or an unsaturated bond (hereinafter, sometimes referred to as a "hydrocarbon group having a halogen atom, etc."), or an alkoxy group having 1 to 10 carbon atoms and having at least one of a halogen atom, a hetero atom, or an unsaturated bond (hereinafter, sometimes referred to as an "alkoxy group having a halogen atom, etc.").

In this specification, the "number of carbon atoms" in a functional group means the total number of carbon atoms in the functional group, unless otherwise specified. In this specification, for example, a "hydrocarbon group having 1 to 10 carbon atoms" is a general term for hydrocarbon groups having 1, 2, 3, ..., or 10 carbon atoms, and this has the same meaning in other functional groups that specify the number of carbon atoms, unless otherwise specified.

Examples of the hydrocarbon group having 1 to 10 carbon atoms in ^X1 and ^X2 include alkyl groups having 1 to 10 carbon atoms. Furthermore, the alkyl group having 1 to 10 carbon atoms is not particularly limited, and examples thereof include chain alkyl groups consisting of methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl and decyl groups, and cyclic alkyl groups such as cyclopentyl and cyclohexyl groups. Examples of the hydrocarbon group having 1 to 10 carbon atoms in ^X1 and ^X2 include hydrocarbon groups having 1, 2, 3, 4, 5 and 6 carbon atoms, and more preferably hydrocarbon groups having 1, 2 and 3 carbon atoms.

The alkoxy group having 1 to 10 carbon atoms in ^X1 and ^X2 is not particularly limited, and examples thereof include linear alkoxy groups such as methoxy group, ethoxy group, propoxy group, butoxy group, pentoxy group, and hexoxy group, cyclic alkoxy groups such as cyclopentoxy group and cyclohexoxy group, phenoxy group, 3-methylphenoxy group, 4-methylphenoxy group, 3,5-dimethylphenoxy group, etc. The alkoxy group having 1 to 10 carbon atoms in ^X1 and ^X2 is preferably an alkoxy group having 1, 2, 3, 4, 5, or 6 carbon atoms, and more preferably an alkoxy group having 1, 2, or 3 carbon atoms.

The hydrocarbon group having a halogen atom and a carbon number of 1 to 10 in ^X1 and ^X2 means a functional group in which part or all of the hydrogen in the hydrocarbon group is substituted with a halogen atom. The halogen atom represents a fluorine, chlorine, bromine, or iodine atom. The hydrocarbon group having a halogen atom and a carbon number of ¹ to 10 in X1 and ^X2 is preferably a hydrocarbon group having a halogen atom and a carbon number of 1, 2, 3, 4, 5, or 6, and more preferably a hydrocarbon group having a halogen atom and a carbon number of 1, 2, or 3.

The hydrocarbon group having a heteroatom with 1 to 10 carbon atoms in ^X1 and ^X2 means a functional group in which some or all of the hydrogen and carbon in the hydrocarbon group are substituted with a heteroatom. The heteroatom represents an atom such as oxygen, nitrogen, or sulfur. The hydrocarbon group having a heteroatom with 1 to 10 carbon atoms in ^X1 and ^X2 is preferably a hydrocarbon group having a heteroatom with 1, 2, 3, 4, 5, or 6 carbon atoms, and more preferably a hydrocarbon group having a heteroatom with 1, 2, or 3 carbon atoms.

Specific examples of the hydrocarbon group having a halogen atom or a hetero atom in ^X1 and ^X2 include an iodomethyl group, a bromomethyl group, a chloromethyl group, a fluoromethyl group, a diiodomethyl group, a dibromomethyl group, a dichloromethyl group, a difluoromethyl group, a triiodomethyl group, a tribromomethyl group, a trichloromethyl group, a trifluoromethyl group, a 2-iodoethyl group, a 2-bromoethyl group, a 2-chloroethyl group, a 2-fluoroethyl group, a 1,2-diiodoethyl group, a 1,2-dibuthyl group, a 1,2-diphenylmethyl ... chain-like halogenated alkyl groups such as 2-iodocyclohexyl group, 2-bromoethyl group, 1,2-dichloroethyl group, 1,2-difluoroethyl group, 2,2-diiodoethyl group, 2,2-dibromoethyl group, 2,2-dichloroethyl group, 2,2-difluoroethyl group, 2,2,2-tribromoethyl group, 2,2,2-trichloroethyl group, 2,2,2-trifluoroethyl group, and hexafluoro-2-propyl group; cyclic halogenated alkyl group such as 1-fluorocyclohexyl group, 2-iodophenyl group, 2-bromophenyl group, 2-chlorophenyl group, 2-fluorophenyl group, 3-iodophenyl group, 3-bromophenyl group, 3-chlorophenyl group, 3-fluorophenyl group, 4-iodophenyl group, 4-bromophenyl group, 4-chlorophenyl group, 4-fluorophenyl group, 2,6-diiodophenyl group, 2,6-dibromophenyl group, 2,6-dichlorophenyl group, 2,6-difluorophenyl group, and halogenated aryl groups such as fluorophenyl group, 3,5-diiodophenyl group, 3,5-dibromophenyl group, 3,5-dichlorophenyl group, 3,5-difluorophenyl group, pentaiodophenyl group, pentabromophenyl group, pentachlorophenyl group, and pentafluorophenyl group; and heteroaryl groups such as 2-nitrophenyl group, 4-nitrophenyl group, 2,4-dinitrophenyl group, 2,6-dinitrophenyl group, and 3-amino-2-naphthyl group.

The hydrocarbon group having 1 to 10 carbon atoms and an unsaturated bond for ^X1 and ^X2 means, for example, a hydrocarbon group having 1 to 10 carbon atoms and a double bond or triple bond between carbon atoms. Furthermore, as the hydrocarbon group having an unsaturated bond, a hydrocarbon group having 1, 2, 3, 4 or 5 unsaturated bonds is preferable, and a hydrocarbon group having 1, 2 or 3 unsaturated bonds is more preferable.

Specific examples of the hydrocarbon group having 1 to 10 carbon atoms and an unsaturated bond in ^X1 and ^X2 include, for example, an ethenyl group, a 1-propenyl group, a 2-propenyl group, an isopropenyl group, a 2-methyl-2-propenyl group, a 2-butenyl group, a 3-butenyl group, a 3-methyl-2-butenyl group, a 1-pentenyl group, a 2-pentenyl group, a 3-pentenyl group, a 4-methyl-2-butenyl group, a 5-methyl-2-butenyl group, a 6-methyl-2-butenyl group, a 7-methyl-2-butenyl group, a 8 ...9-methyl-2-butenyl group, a 10-methyl-2-butenyl group, a 11-methyl-2-butenyl group, a 12-methyl-2-butenyl group, a 13-methyl-2-butenyl group, a 14-methyl-2-butenyl group, a 15-methyl-2-butenyl group, a 16-methyl-2-butenyl group, a 17-methyl-2-butenyl group, a 18-methyl-2-butenyl group, a 19-methyl-2-butenyl group, a 20-methyl-2-butenyl group, a 21-methyl-2-butenyl group, a 22-methyl-2-butenyl group, a 23-methyl-2-butenyl group, a 24-methyl-2 -pentenyl group, penta-1,4-dienyl group, penta-2,4-dienyl group, 1-hexenyl group, 2-hexenyl group, 3-hexenyl group, 4-hexenyl group, 5-hexenyl group, hexa-1,3-dienyl group, hexa-1,5-dienyl group, hexa-2,4-dienyl group, hexa-2,5-dienyl group, hexa-3,5-dienyl group and 3-methyl-1,3-dienyl group. chain alkenyl groups such as ethyl-hexa-2,4-dienyl group; cyclic alkenyl groups such as 1-cyclopentenyl group, 2-cyclopentenyl group, 2,4-cyclopentadienyl group, 1-cyclohexenyl group, 2-cyclohexenyl group, and 3-cyclohexenyl group; aryl groups such as phenyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 2,6-dimethylphenyl group, 3,5-dimethylphenyl group, 2,4,6-trimethylphenyl group, 1-naphthyl group, and 2-naphthyl group; and chain alkynyl groups such as ethynyl group, 2-propynyl group, butynyl group, 2-butynyl group, 3-butynyl group, pentynyl group, 2-pentynyl group, 3-pentynyl group, and 4-pentynyl group.

The alkoxy group having a halogen atom and a carbon number of 1 to 10 in ^X1 and ^X2 means a functional group in which part or all of the hydrogen in the alkoxy group is substituted with a halogen atom. Here, the halogen atom means a fluorine, chlorine, bromine, or iodine atom, as in the above case. As the alkoxy group having a halogen atom and a carbon number of 1 to 10 in ^X1 and ^X2 , an alkoxy group having a halogen atom and a carbon number of 1, 2, 3, 4, 5, or 6 is preferable, and an alkoxy group having a halogen atom and a carbon number of 1, 2, or 3 is more preferable.

In addition, the alkoxy group having a heteroatom with 1 to 10 carbon atoms in ^X1 and ^X2 means a functional group in which some or all of the hydrogen and carbon in the alkoxy group are substituted with a heteroatom. Here, the heteroatom means an atom such as oxygen, nitrogen, or sulfur, as in the above-mentioned case. As the alkoxy group having a heteroatom with 1 to 10 carbon atoms in ^X1 and ^X2 , an alkoxy group having a heteroatom with 1, 2, 3, 4, 5, or 6 carbon atoms is preferable, and an alkoxy group having a heteroatom with 1, 2, or 3 carbon atoms is more preferable.

Specific examples of the alkoxy group having a halogen atom or a hetero atom in ^X1 and ^X2 include an iodomethoxy group, a bromomethoxy group, a chloromethoxy group, a fluoromethoxy group, a diiodomethoxy group, a dibromomethoxy group, a dichloromethoxy group, a difluoromethoxy group, a triiodomethoxy group, a tribromomethoxy group, a trichloromethoxy group, a trifluoromethoxy group, a 2-iodoethoxy group, a 2-bromoethoxy group, a 2-chloroethoxy group, a 2-fluoroethoxy group, a 1,2-diiodoethoxy group, a 1,2-dibutyl group, a 1,2-diphenyl ... chain-like halogenated alkoxy groups such as bromoethoxy group, 1,2-dichloroethoxy group, 1,2-difluoroethoxy group, 2,2-diiodoethoxy group, 2,2-dibromoethoxy group, 2,2-dichloroethoxy group, 2,2-difluoroethoxy group, 2,2,2-tribromoethoxy group, 2,2,2-trichloroethoxy group, 2,2,2-trifluoroethoxy group, and hexafluoro-2-propoxy group; 2-iodocyclohexyloxy group, 2-bromocyclohexyloxy group, and 2-chlorocyclohexyloxy group and cyclic halogenated alkoxy groups such as 2-fluorocyclohexyloxy group, 2-iodophenoxy group, 2-bromophenoxy group, 2-chlorophenoxy group, 2-fluorophenoxy group, 3-iodophenoxy group, 3-bromophenoxy group, 3-chlorophenoxy group, 3-fluorophenoxy group, 4-iodophenoxy group, 4-bromophenoxy group, 4-chlorophenoxy group, 4-fluorophenoxy group, 2,6-diiodophenoxy group, 2,6-dibromophenoxy group, 2,6-dichlorophenoxy group, 2, Examples of halogenated aryl groups include 6-difluorophenoxy group, 3,5-diiodophenoxy group, 3,5-dibromophenoxy group, 3,5-dichlorophenoxy group, 3,5-difluorophenoxy group, pentaiodophenoxy group, pentabromophenoxy group, pentachlorophenoxy group, and pentafluorophenoxy group; and heteroaryl groups such as 2-nitrophenoxy group, 4-nitrophenoxy group, 2,4-dinitrophenoxy group, 2,6-dinitrophenoxy group, and 3-amino-2-naphthoxy group.

The alkoxy group having 1 to 10 carbon atoms and an unsaturated bond in ^X1 and ^X2 means, for example, an alkoxy group having a double bond or a triple bond between carbon and carbon. Furthermore, the alkoxy group having an unsaturated bond is preferably an alkoxy group having 1, 2, 3, 4 or 5 unsaturated bonds, and more preferably an alkoxy group having 1, 2 or 3 unsaturated bonds.

Specific examples of the alkoxy group having an unsaturated bond and having 1 to 10 carbon atoms in ^X1 and ^X2 include, for example, an ethenyloxy group, a 1-propenyloxy group, a 2-propenyloxy group, an isopropenyloxy group, a 2-methyl-2-propenyloxy group, a 2-butenyloxy group, a 3-butenyloxy group, a 3-methyl-2-butenyloxy group, a 1-pentenyloxy group, a 2-pentenyloxy group, a 3-pentenyloxy group, a 4-pentenyloxy group, oxy group, penta-1,4-dienyloxy group, penta-2,4-dienyloxy group, 1-hexenyloxy group, 2-hexenyloxy group, 3-hexenyloxy group, 4-hexenyloxy group, 5-hexenyloxy group, hexa-1,3-dienyloxy group, hexa-1,5-dienyloxy group, hexa-2,4-dienyloxy group, hexa-2,5-dienyloxy group, hexa-3,5-dienyloxy group, and 3-methyloxy group. chain alkenyloxy groups such as 1-cyclopentenyloxy group, 2-cyclopentenyloxy group, 2,4-cyclopentadienyloxy group, 1-cyclohexenyloxy group, 2-cyclohexenyloxy group, and 3-cyclohexenyloxy group; phenoxy group, 2-methylphenoxy group, 3-methylphenoxy group, 4-methylphenoxy group, 2,6-dimethylphenoxy group, and the like; and aryloxy groups such as arylphenoxy group, 3,5-dimethylphenoxy group, 2,4,6-trimethylphenoxy group, 1-naphthoxy group and 2-naphthoxy group; and chain alkynyloxy groups such as ethynyloxy group, 2-propynyloxy group, butynyloxy group, 2-butynyloxy group, 3-butynyloxy group, pentynyloxy group, 2-pentynyloxy group, 3-pentynyloxy group and 4-pentynyloxy group.

^X1 and ^X2 may be the same or different from each other. The functional groups listed above as ^X1 and ^X2 are merely examples, and the present embodiment is not limited thereto.

X ³ to X ⁵ in the chemical formula (A) each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a hydrocarbon group having a halogen atom, etc., or an alkoxy group having a halogen atom, etc. Furthermore, at least one of X ³ to X ⁵ is either the hydrocarbon group having 1 to 10 carbon atoms or the alkoxy group having 1 to 10 carbon atoms.

The hydrocarbon group having 1 to 10 carbon atoms, the alkoxy group having 1 to 10 carbon atoms, the hydrocarbon group having a halogen atom or the like, and the alkoxy group having a halogen atom or the like are the same as those described above for ^X1 and ^X2 . Therefore, the details thereof will be omitted.

X ³ to X ⁵ may be the same or different from each other. The functional groups listed above as X ³ to X ⁵ are merely examples, and the present embodiment is not limited thereto.

Specific examples of the phosphate ester represented by the chemical formula (A) include, for example, trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate, tripentyl phosphate, trihexyl phosphate, 2-ethylhexyl diphenyl phosphate, triallyl phosphate, tripropargyl phosphate, tris(2-butoxyethyl)phosphate, tris(2-chloroethyl)phosphate, ethyl bis(2,2,2-trifluoroethyl)phosphate, diethyl 2,2,2-trifluoroethyl phosphate, tris(2,2,2-trifluoroethyl)phosphate, tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphate, dimethyl fluorophosphate, diethyl fluorophosphate, dipropyl fluorophosphate, dibutyl fluorophosphate, dipentyl fluorophosphate, dihexyl fluorophosphate, 2-ethylhexylphenyl fluorophosphate, diallyl fluorophosphate, dipropargyl fluorophosphate, bis(2-butoxyethyl)fluorophosphate, bis(2-chloroethyl)fluorophosphate, bis(2,2,2-trifluoroethyl)fluorophosphate, bis(1,1,1,3,3,3-hexafluoro-2-propyl)fluorophosphate, methyl difluorophosphate, ethyl difluorophosphate, propyl difluorophosphate, allyl difluorophosphate, propargyl difluorophosphate, 2-butoxyethyl difluorophosphate, 2-chloroethyl difluorophosphate, 2,2,2-trifluoroethyl difluorophosphate, 1,1,1,3,3,3-hexafluoro-2-propyl difluorophosphate, dimethyltrimethylsilyl phosphate, diethyltrimethylsilyl phosphate, Tylsilyl phosphate, trimethylsilyl dipropyl phosphate, dibutyl trimethylsilyl phosphate, trimethylsilyl dipentyl phosphate, dihexyl trimethylsilyl phosphate, trimethylsilyl diphenyl phosphate, diallyl trimethylsilyl phosphate, trimethylsilyl dipropargyl phosphate, bis(2-butoxyethyl)trimethylsilyl phosphate, bis(2-chloroethyl)trimethylsilyl phosphate, bis(2,2,2-trifluoroethyl)trimethylsilyl phosphate, bis(1,1,1,3,3,3-hexafluoro-2-propyl)trimethylsilyl phosphate, methyl trimethylsilyl fluorophosphate, ethyl trimethylsilyl fluorophosphate, trimethylsilyl(propyl)fluorophosphate, butyl trimethylsilyl fluorophosphate, trimethylsilyl(pentyl)fluorophosphate phosphate, hexyltrimethylsilylfluorophosphate, trimethylsilyl(phenyl)fluorophosphate, allyltrimethylsilylfluorophosphate, trimethylsilyl(propargyl)fluorophosphate, 2-butoxyethyltrimethylsilylfluorophosphate, 2-chloroethyltrimethylsilylfluorophosphate, 2,2,2-trifluoroethyltrimethylsilylfluorophosphate, 1,1,1,3,3,3-hexafluoro-2-propyltrimethylsilylfluorophosphate, trimethylsilyldifluorophosphate, dimethylvinylsilyldifluorophosphate, dimethylphenylsilyldifluorophosphate, triethylsilyldifluorophosphate, cyclohexyldimethylsilyldifluorophosphate, triisopropylsilyldifluorophosphate, methyldiphenylsilyldifluorophosphate, etc. However, the phosphate ester represented by the chemical formula (A) is not limited to these compound groups.

<Raw material salt>
The raw material salt is represented by the following chemical formula (B).

In the chemical formula (B), M represents an alkali metal, an alkaline earth metal, aluminum, a transition metal, or an onium.

The alkali metal is not particularly limited, and examples thereof include Li, Na, K, Rb, and Cs. Among these alkali metals, Li, Na, and K are preferred from the viewpoint of availability, and Li and Na are more preferred from the viewpoint of versatility of phosphate compounds.

The alkaline earth metal is not particularly limited, and examples thereof include Be, Mg, Ca, Sr, and Ba. Among these alkaline earth metals, Mg, Ca, and Ba are preferred from the viewpoints of availability and safety, and Mg is more preferred from the viewpoint of versatility of phosphate compounds.

The transition metals are not particularly limited, and examples include Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn. Among these transition metals, Ti, Mn, Fe, Co, Ni, and Cu are preferred from the viewpoint of availability.

The onium is not particularly limited, and examples thereof include primary ammonium, secondary ammonium, tertiary ammonium, quaternary ammonium, quaternary phosphonium, and sulfonium.

The primary ammonium is not particularly limited, and examples thereof include methylammonium, ethylammonium, propylammonium, isopropylammonium, etc. These may be used alone or in combination of two or more.

The secondary ammonium is not particularly limited, and examples thereof include dimethylammonium, diethylammonium, dipropylammonium, dibutylammonium, ethylmethylammonium, methylpropylammonium, butylmethylammonium, butylpropylammonium, and diisopropylammonium.

The tertiary ammonium is not particularly limited, and examples thereof include trimethylammonium, triethylammonium, tripropylammonium, tributylammonium, ethyldimethylammonium, diethylmethylammonium, triisopropylammonium, dimethylisopropylammonium, diethylisopropylammonium, dimethylpropylammonium, butyldimethylammonium, 1-methylpyrrolidinium, 1-ethylpyrrolidinium, 1-propylpyrrolidinium, 1-butylpropylpyrrolidinium, 1-methylimidazolium, 1-ethylimidazolium, 1-propylimidazolium, 1-butylimidazolium, pyrazolium, 1-methylpyrazolium, 1-ethylpyrazolium, 1-propylpyrazolium, 1-butylpyrazolium, pyridinium, and the like.

The quaternary ammonium is not particularly limited, and examples thereof include aliphatic quaternary ammoniums, imidazoliums, pyridiniums, pyrazoliums, pyridaziniums, etc.

Furthermore, the aliphatic quaternary ammoniums are not particularly limited, and examples thereof include tetraethylammonium, tetrapropylammonium, tetraisopropylammonium, ethyltrimethylammonium, diethyldimethylammonium, triethylmethylammonium, trimethylpropylammonium, trimethylisopropylammonium, tetrabutylammonium, butyltrimethylammonium, trimethylpentylammonium, hexyltrimethylammonium, 1-methyl-1-propylpyrrolidinium, 1-ethyl-1-methyl-pyrrolidinium, 1-butyl-1-methylpyrrolidinium, 1-ethyl-1-methyl-piperidinium, 1-butyl-1-methylpiperidinium, and the like.

The imidazoliums are not particularly limited, and examples thereof include 1,3-dimethyl-imidazolium, 1-ethyl-3-methylimidazolium, 1-n-propyl-3-methylimidazolium, 1-n-butyl-3-methylimidazolium, and 1-n-hexyl-3-methylimidazolium.

The pyridiniums are not particularly limited, and examples include 1-methylpyridinium, 1-ethylpyridinium, and 1-n-propylpyridinium.

The pyrazoliums are not particularly limited, and examples thereof include 1,2-dimethylpyrazolium, 2-ethyl-1-methylpyrazolium, 2-methyl-1-propylpyrazolium, 2-butyl-1-methylpyrazolium, 1-methylpyrazolium, 3-methylpyrazolium, 4-methylpyrazolium, 4-iodopyrazolium, 4-bromopyrazolium, 4-iodo-3-methylpyrazolium, 4-bromo-3-methylpyrazolium, and 3-trifluoromethylpyrazolium.

The pyridaziniums are not particularly limited, and examples thereof include 1-methylpyridazinium, 1-ethylpyridazinium, 1-propylpyridazinium, 1-butylpyridazinium, 3-methylpyridazinium, 4-methylpyridazinium, 3-methoxypyridazinium, 3,6-dichloropyridazinium, 3,6-dichloro-4-methylpyridazinium, 3-chloro-6-methylpyridazinium, and 3-chloro-6-methoxypyridazinium.

Among the oniums given above, tetraethylammonium, triethylmethylammonium, 1-methyl-1-propylpyrrolidinium, and 1-ethyl-3-methylimidazolium are preferred from the standpoint of availability and versatility.

Examples of the halogen atom in ^X6 include fluorine, chlorine, bromine, and iodine atoms. Among these halogen atoms, from the viewpoints of high elimination ability and reuse of by-products, chlorine, bromine, and iodine atoms are preferred.

The alkoxy group having 1 to 10 carbon atoms in ^X6 is not particularly limited, and examples thereof include linear alkoxy groups such as methoxy group, ethoxy group, propoxy group, butoxy group, pentoxy group, and hexoxy group, cyclic alkoxy groups such as cyclopentoxy group and cyclohexoxy group, phenoxy group, 3-methylphenoxy group, 4-methylphenoxy group, 3,5-dimethylphenoxy group, etc. The alkoxy group having 1 to 10 carbon atoms in ^X6 is preferably an alkoxy group having 1, 2, 3, 4, 5, or 6 carbon atoms, and more preferably an alkoxy group having 1, 2, or 3 carbon atoms.

The haloacyloxy group in ^X6 is not particularly limited, but is preferably a functional group having 1 to 7 carbon atoms and having one or more hydrogen atoms substituted with halogen atoms. Specific examples include an iodoacetyl group, a bromoacetyl group, a chloroacetyl group, a fluoroacetyl group, a diiodoacetyl group, a dibromoacetyl group, a dichloroacetyl group, a difluoroacetyl group, a triiodoacetyl group, a tribromoacetyl group, a trichloroacetyl group, a trifluoroacetyl group, a 3,3,3-triiodopropanoyl group, a 3,3,3-tribromopropanoyl group, a 3,3,3-trichloropropanoyl group, a 3,3,3-trifluoropropanoyl group, a pentaiodopropanoyl group, a pentabromopropanoyl group, a pentachloropropanoyl group, a pentafluoropropanoyl group, a 4,4,4-trifluoroacetyl group, a 5,5,6-trifluoroacetyl group, a 6,6,7-trifluoroacetyl group, a 7,7,8-trifluoroacetyl group, a 8,8,9-trifluoroacetyl group, a 9,9,10-trifluoroacetyl group, a 10,11,12-trifluoroacetyl group, a 12,13,14-trifluoroacetyl group, a 14,14,15-trifluoroacetyl group, a 15,16,17-trifluoroacetyl group, a 17,18,19-trifluoroacetyl group, a 19,19,12-trifluoroacetyl group, a 20,13,14-trifluoroacetyl group, a 21,14,15-trifluoroacetyl group, a 22,15,16-trifluoroacetyl group, a 23,16,17-trifluoroacetyl group, a 24,18,19-trifluoroacetyl group, a 25,19,18-trifluoroacetyl group, a 26,19,19-trifluoroacetyl group, a Examples of the halogen atom include iodobutanoyl group, 4,4,4-tribromobutanoyl group, 4,4,4-trichlorobutanoyl group, 4,4,4-trifluorobutanoyl group, 3,3,4,4,4-pentaiodobutanoyl group, 3,3,4,4,4-pentabromobutanoyl group, 3,3,4,4,4-pentachlorobutanoyl group, 3,3,4,4,4-pentafluorobutanoyl group, heptaiodobutanoyl group, heptabromobutanoyl group, heptachlorobutanoyl group, heptafluorobutanoyl group, pentaiodobenzoyl group, pentabromobenzoyl group, pentachlorobenzoyl group, and pentafluorobenzoyl group. The halogen atom represents fluorine, chlorine, bromine, and iodine.

The sulfonyloxy group in ^X6 is represented by a _-SO3Y group, where Y represents a halogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a hydrocarbon group having 1 to 10 carbon atoms and having at least one of a halogen atom, a heteroatom, or an unsaturated bond.

The halogen atoms in Y include fluorine, chlorine, bromine, and iodine atoms.

The hydrocarbon group having 1 to 10 carbon atoms in Y is not particularly limited, and examples thereof include linear alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, and octyl, and cyclic alkyl groups such as cyclopentyl and cyclohexyl. The hydrocarbon group having 1 to 10 carbon atoms in Y is preferably a hydrocarbon group having 1, 2, 3, 4, 5, or 6 carbon atoms, and more preferably a hydrocarbon group having 1, 2, or 3 carbon atoms.

The hydrocarbon group having a halogen atom and a carbon number of 1 to 10 in Y means a functional group in which some or all of the hydrogen atoms in the hydrocarbon group are replaced with halogen atoms. The halogen atoms represent fluorine, chlorine, bromine, and iodine atoms. As the hydrocarbon group having a halogen atom and a carbon number of 1 to 10 in Y, a hydrocarbon group having a halogen atom and a carbon number of 1, 2, 3, 4, 5, or 6 is preferable, and a hydrocarbon group having a halogen atom and a carbon number of 1, 2, or 3 is more preferable.

The hydrocarbon group having a heteroatom with 1 to 10 carbon atoms in Y means a functional group in which some or all of the hydrogen and carbon in the hydrocarbon group are replaced with a heteroatom. The heteroatom represents an atom such as oxygen, nitrogen, or sulfur. As the hydrocarbon group having a heteroatom with 1 to 10 carbon atoms in Y, a hydrocarbon group having a heteroatom with 1, 2, 3, 4, 5, or 6 carbon atoms is preferable, and a hydrocarbon group having a heteroatom with 1, 2, or 3 carbon atoms is more preferable.

Specific examples of the hydrocarbon group having a carbon number of 1 to 10 and a halogen atom or a heteroatom in Y include, for example, an iodomethyl group, a bromomethyl group, a chloromethyl group, a fluoromethyl group, a diiodomethyl group, a dibromomethyl group, a dichloromethyl group, a difluoromethyl group, a triiodomethyl group, a tribromomethyl group, a trichloromethyl group, a trifluoromethyl group, a 2-iodoethyl group, a 2-bromoethyl group, a 2-chloroethyl group, a 2-fluoroethyl group, a 1,2-di Chain halogenated alkyl groups such as an iodoethyl group, a 1,2-dibromoethyl group, a 1,2-dichloroethyl group, a 1,2-difluoroethyl group, a 2,2-diiodoethyl group, a 2,2-dibromoethyl group, a 2,2-dichloroethyl group, a 2,2-difluoroethyl group, a 2,2,2-tribromoethyl group, a 2,2,2-trichloroethyl group, a 2,2,2-trifluoroethyl group, and a hexafluoro-2-propyl group; a 2-iodocyclohexyl group, a 2-bromocyclohexyl group, a 2-chlorocyclohexyl group, a cyclic halogenated alkyl groups such as 2-cyclohexyl and 2-fluorocyclohexyl groups, 2-iodophenyl group, 2-bromophenyl group, 2-chlorophenyl group, 2-fluorophenyl group, 3-iodophenyl group, 3-bromophenyl group, 3-chlorophenyl group, 3-fluorophenyl group, 4-iodophenyl group, 4-bromophenyl group, 4-chlorophenyl group, 4-fluorophenyl group, 2,6-diiodophenyl group, 2,6-dibromophenyl group, 2,6-dichlorophenyl group, 2, Examples of halogenated aryl groups include 6-difluorophenyl, 3,5-diiodophenyl, 3,5-dibromophenyl, 3,5-dichlorophenyl, 3,5-difluorophenyl, pentaiodophenyl, pentabromophenyl, pentachlorophenyl and pentafluorophenyl groups; and heteroaryl groups such as 2-nitrophenyl, 4-nitrophenyl, 2,4-dinitrophenyl, 2,6-dinitrophenyl and 3-amino-2-naphthyl groups.

The hydrocarbon group for Y having 1 to 10 carbon atoms and an unsaturated bond means, for example, a hydrocarbon group having 1 to 10 carbon atoms and a double bond or triple bond between carbon atoms. Furthermore, the hydrocarbon group having an unsaturated bond is preferably a hydrocarbon group having 1, 2, 3, 4, or 5 unsaturated bonds, and more preferably a hydrocarbon group having 1, 2, or 3 unsaturated bonds.

Specific examples of the hydrocarbon group having an unsaturated bond and having 1 to 10 carbon atoms in Y include, for example, ethenyl, 1-propenyl, 2-propenyl, isopropenyl, 2-methyl-2-propenyl, 2-butenyl, 3-butenyl, 3-methyl-2-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl group, penta-1,4-dienyl group, penta-2,4-dienyl group, 1-hexenyl group, 2-hexenyl group, 3-hexenyl group, 4-hexenyl group, 5-hexenyl group, hexa-1,3-dienyl group, hexa-1,5-dienyl group, hexa-2,4-dienyl group, hexa-2,5-dienyl group, hexa-3,5-dienyl group and 3-methyl-1,3-dienyl group. chain alkenyl groups such as ethyl-hexa-2,4-dienyl group; cyclic alkenyl groups such as 1-cyclopentenyl group, 2-cyclopentenyl group, 2,4-cyclopentadienyl group, 1-cyclohexenyl group, 2-cyclohexenyl group, and 3-cyclohexenyl group; aryl groups such as phenyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 2,6-dimethylphenyl group, 3,5-dimethylphenyl group, 2,4,6-trimethylphenyl group, 1-naphthyl group, and 2-naphthyl group; chain alkynyl groups such as ethynyl group, 2-propynyl group, butynyl group, 2-butynyl group, 3-butynyl group, pentynyl group, 2-pentynyl group, 3-pentynyl group, and 4-pentynyl group.

Specific examples of the raw material salt represented by the chemical formula (B) include, for example, lithium fluoride, lithium chloride, lithium bromide, lithium iodide, sodium fluoride, sodium chloride, sodium bromide, sodium iodide, potassium fluoride, potassium chloride, potassium bromide, potassium iodide, cesium fluoride, cesium chloride, cesium bromide, cesium iodide, magnesium fluoride, magnesium chloride, magnesium bromide, magnesium iodide, calcium fluoride, calcium chloride, calcium bromide, calcium iodide, aluminum fluoride, aluminum chloride, aluminum bromide, aluminum iodide, manganese chloride (II), manganese bromide (II), manganese iodide (II), nickel chloride (II), nickel bromide (II), nickel iodide (II), cobalt chloride (II), cobalt bromide (II), cobalt iodide (II), salt Examples of the copper(II) chloride, copper(II) bromide, copper(II) iodide, tetraethylammonium fluoride, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide, triethylmethylammonium fluoride, triethylmethylammonium chloride, triethylmethylammonium bromide, triethylmethylammonium iodide, 1-propyl-1-methylpyrrolidinium fluoride, 1-propyl-1-methylpyrrolidinium chloride, 1-propyl-1-methylpyrrolidinium bromide, 1-propyl-1-methylpyrrolidinium iodide, 1-ethyl-3-methylimidazolium fluoride, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium bromide, 1-ethyl-3-methylimidazolium iodide, etc. However, the raw material salt represented by the above chemical formula (B) is not limited to these compound groups.

The n is the valence and represents a natural number from 1 to 4.

<Phosphate Compounds>
The phosphate compound is represented by the following chemical formula (C).

In the chemical formula (C), M represents the same cationic species as in the chemical formula (A). Also, ^X1 and ^X2 represent the same functional groups as in the chemical formula (A). Therefore, detailed explanations of these will be omitted.

Specific examples of the phosphate compound represented by the chemical formula (C) include, for example, lithium diethyl phosphate, sodium diethyl phosphate, potassium diethyl phosphate, magnesium diethyl phosphate, calcium diethyl phosphate, aluminum diethyl phosphate, manganese (II) diethyl phosphate, nickel (II) diethyl phosphate, cobalt (II) diethyl phosphate, copper (II) diethyl phosphate, tetraethylammonium diethyl phosphate, triethylmethylammonium diethyl phosphate, 1-propyl-1-methylpyrrolidinium diethyl phosphate, 1-ethyl-3-methylimidazolium diethyl phosphate, lithium dipropyl phosphate, sodium dipropyl phosphate, dipropyl phosphate, potassium dipropyl phosphate, magnesium dipropyl phosphate, calcium dipropyl phosphate, aluminum dipropyl phosphate, manganese(II) dipropyl phosphate, nickel(II) dipropyl phosphate, cobalt(II) dipropyl phosphate, copper(II) dipropyl phosphate, tetraethylammonium dipropyl phosphate, triethylmethylammonium dipropyl phosphate, 1-propyl-1-methylpyrrolidinium dipropyl phosphate, 1-ethyl-3-methylimidazolium dipropyl phosphate, lithium dibutyl phosphate, sodium dibutyl phosphate, potassium dibutyl phosphate, magnesium dibutyl phosphate, calcium dibutyl phosphate, aluminum dibutyl phosphate, manganese dibutyl phosphate ammonium dibutyl phosphate, tetraethylammonium dibutyl phosphate, triethylmethylammonium dibutyl phosphate, 1-propyl-1-methylpyrrolidinium dibutyl phosphate, 1-ethyl-3-methylimidazolium dibutyl phosphate, lithium bis(2,2,2-trifluoroethyl)phosphate, sodium bis(2,2,2-trifluoroethyl)phosphate, potassium bis(2,2,2-trifluoroethyl)phosphate, magnesium bis(2,2,2-trifluoroethyl)phosphate, calcium bis(2,2,2-trifluoroethyl)phosphate, bis(2,2,2-trifluoroethyl)phosphate, bis(2,2,2-trifluoroethyl)aluminum phosphate, bis(2,2,2-trifluoroethyl)manganese(II) phosphate, bis(2,2,2-trifluoroethyl)nickel(II) phosphate, bis(2,2,2-trifluoroethyl)cobalt(II) phosphate, bis(2,2,2-trifluoroethyl)copper(II) phosphate, tetraethylammonium bis(2,2,2-trifluoroethyl)phosphate, triethylmethylammonium bis(2,2,2-trifluoroethyl)phosphate, 1-propyl-1-methylpyrrolidinium bis(2,2,2-trifluoroethyl)phosphate, 1-ethyl-3-methylimidazolium bis(2,2,2-trifluoroethyl)phosphate, ethyl(2,2,2-trifluoroethyl)phosphate, ethyl(2,2,2-trifluoroethyl)phosphate lithium, ethyl(2,2,2-trifluoroethyl)phosphate sodium, ethyl(2,2,2-trifluoroethyl)phosphate potassium, ethyl(2,2,2-trifluoroethyl)phosphate magnesium, ethyl(2,2,2-trifluoroethyl)phosphate calcium, ethyl(2,2,2-trifluoroethyl)phosphate aluminum, ethyl(2,2,2-trifluoroethyl)phosphate manganese(II), ethyl(2,2,2-trifluoroethyl)phosphate nickel(II), ethyl(2,2,2-trifluoroethyl)phosphate cobalt(II), ethyl(2,2,2-trifluoroethyl)phosphate copper(II), tetraethylammonium ethyl(2,2,2-trifluoroethyl)phosphate ethyl)phosphate, triethylmethylammonium ethyl (2,2,2-trifluoroethyl)phosphate, 1-propyl-1-methylpyrrolidinium ethyl (2,2,2-trifluoroethyl)phosphate, 1-ethyl-3-methylimidazolium ethyl (2,2,2-trifluoroethyl)phosphate, lithium 2,2,2-trifluoroethyl fluorophosphate, sodium 2,2,2-trifluoroethyl fluorophosphate, potassium 2,2,2-trifluoroethyl fluorophosphate, magnesium 2,2,2-trifluoroethyl fluorophosphate, calcium 2,2,2-trifluoroethyl fluorophosphate, aluminum 2,2,2-trifluoroethyl fluoroethyl fluorophosphate, manganese(II) 2,2,2-trifluoroethyl fluorophosphate, nickel(II) 2,2,2-trifluoroethyl fluorophosphate, cobalt(II) 2,2,2-trifluoroethyl fluorophosphate, copper(II) 2,2,2-trifluoroethyl fluorophosphate, tetraethylammonium 2,2,2-trifluoroethyl fluorophosphate, triethylmethylammonium 2,2,2-trifluoroethyl fluorophosphate, 1-propyl-1-methylpyrrolidinium 2,2,2-trifluoroethyl fluorophosphate, 1-ethyl-3-methylimidazolium 2,2,2-trifluoroethyl fluorophosphate , lithium difluorophosphate, sodium difluorophosphate, potassium difluorophosphate, cesium difluorophosphate, magnesium difluorophosphate, calcium difluorophosphate, aluminum difluorophosphate, manganese (II) difluorophosphate, nickel (II) difluorophosphate, cobalt (II) difluorophosphate, copper (II) difluorophosphate, tetraethylammonium difluorophosphate, triethylmethylammonium difluorophosphate, 1-propyl-1-methylpyrrolidinium difluorophosphate, 1-ethyl-3-methylimidazolium difluorophosphate, etc. However, the phosphate compound represented by the chemical formula (C) is not limited to these compound groups.

<Reaction conditions for step (I)>
The reaction molar ratio in the step (I) is not particularly limited and may be appropriately set depending on the reactant species. In the reaction molar ratio of the phosphoric acid ester to the raw material salt, the lower limit of the phosphoric acid ester is usually 1 mole or more per mole of the raw material salt. The upper limit of the phosphoric acid ester is usually 2.5 moles or less, and preferably 1.5 moles or less from the viewpoint of industrial production.

The reaction initiation temperature in step (I) is not particularly limited as long as the reaction proceeds, and may be set appropriately depending on the type of reaction. The lower limit of the reaction initiation temperature is usually 0°C or higher, and from the viewpoint of reactivity, it is preferably 20°C or higher, and more preferably 60°C or higher. The upper limit of the reaction initiation temperature is usually 150°C or lower, and from the viewpoint of reactivity, it is preferably 120°C or lower, and more preferably 100°C or lower. By setting the lower limit of the reaction initiation temperature to 0°C or higher, it is possible to prevent the reaction rate from significantly decreasing. On the other hand, by setting the upper limit of the reaction initiation temperature to 150°C or lower, it is possible to suppress the excess energy used in the reaction.

There are no particular limitations on the means for adjusting the reaction initiation temperature. For example, when controlling the reaction initiation temperature by cooling so that it is within the above-mentioned temperature range, this can be done by ice-cooling the reaction vessel into which the phosphate ester and raw material salt are added. Also, when controlling the reaction initiation temperature by heating so that it is within the above-mentioned temperature range, this can be done by using an oil bath set to any desired temperature.

The reaction time in step (I) is not particularly limited and may be set appropriately depending on the reactant species. The lower limit of the reaction time is usually 1 hour or more. The upper limit of the reaction time is usually 10 hours or less, and from the viewpoint of industrial production, 6 hours or less is preferable, and 4 hours or less is more preferable.

The reaction in step (I) can be carried out without a solvent or in a non-aqueous solvent. When the reaction in step (I) is carried out without a solvent, the phosphate ester also functions as a reaction solvent.

The non-aqueous solvent is not particularly limited as long as it does not cause any problems such as reaction with other reactants or products, but it is preferable to use an aprotic organic solvent.

The aprotic organic solvent is not particularly limited, and examples thereof include alcohols, nitriles, esters, ketones, ethers, halogenated hydrocarbons, etc. These may be used alone or in combination of two or more.

The alcohols are not particularly limited, and examples thereof include methanol, ethanol, propanol, 2-propanol, butanol, pentanol, hexanol, heptanol, octanol, 2-iodoethanol, 2-bromoethanol, 2-chloroethanol, 2-fluoroethanol, 1,2-diiodoethanol, 1,2-dibromoethanol, 1,2-dichloroethanol, 1,2-difluoroethanol, 2,2-diiodoethanol, 2,2-dibromoethanol, 2,2-dichloroethanol, 2,2-difluoroethanol, 2,2,2-tribromoethanol, 2,2,2-trichloroethanol, 2,2,2-trifluoroethanol, and hexafluoro-2-propanol. These may be used alone or in combination.

The nitriles are not particularly limited, and examples thereof include acetonitrile, propanenitrile, and the like. These may be used alone or in combination of two or more.

The esters are not particularly limited, and examples thereof include dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, ethylene carbonate, propylene carbonate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, etc. These may be used alone or in combination of two or more.

The ketones are not particularly limited, and examples thereof include acetone, ethyl methyl ketone, isobutyl methyl ketone, cyclohexanone, etc. These can be used alone or in combination of two or more.

The ethers are not particularly limited, and examples thereof include diethyl ether, tetrahydrofuran, dioxane, dimethoxyethane, etc. These may be used alone or in combination of two or more.

The halogenated hydrocarbon is not particularly limited, and examples thereof include dichloromethane, chloroform, 1,1,2,2-tetrachloroethane, chlorobenzene, etc. These may be used alone or in combination of two or more.

Other examples of non-aqueous solvents include toluene, N,N-dimethylformamide, dimethyl sulfoxide, nitromethane, and nitroethane.

Among the non-aqueous solvents exemplified above, in the present invention, nitriles, esters, ketones, ethers, and halogenated hydrocarbons are preferred from the viewpoints of solubility of the reaction substrate and ease of availability.

The lower limit of the amount of the nonaqueous solvent used is preferably 1 mol or more, more preferably 10 mol or more, per mol of the phosphate ester. The upper limit of the amount of the nonaqueous solvent used is preferably 10,000 mol or less, more preferably 1,000 mol or less, and even more preferably 100 mol or less, per mol of the phosphate ester. By setting the lower limit of the amount of the nonaqueous solvent to 1 mol or more, it is possible to prevent a decrease in the reactivity between the phosphate ester and the raw salt, and to suppress a decrease in the yield and purity of the phosphate compound. On the other hand, by setting the upper limit of the amount of the nonaqueous solvent used to 10,000 mol or less, it is possible to suppress the energy required for distilling it off, and to prevent it from becoming a disadvantage in industrial production.

The phosphate compound obtained in step (I) may be isolated and purified depending on its purity. The method is not particularly limited, and any known method can be used. Specific examples include atmospheric distillation, reduced pressure distillation, filtration, filtration, recrystallization, sublimation purification, silica gel column chromatography, preparative thin layer chromatography (PTLC), high performance liquid chromatography (HPLC), and ion chromatography (IC).

(Method for producing phosphoric acid ester)
When Z is a silicon atom, the phosphoric acid ester can be obtained by a known production method using an acid anhydride or the like as a raw material. However, in this embodiment, as shown in the chemical reaction formula below, it is preferable to include a step (II) of reacting a phosphoric acid compound represented by chemical formula (D) with a silicon compound represented by chemical formula (E) to produce a phosphoric acid silyl ester represented by chemical formula (F). This makes it possible to efficiently obtain the phosphoric acid ester.

The reaction in step (II) makes it possible to reuse the silicon compound by-produced in step (I) as the silicon compound represented by the chemical formula (E). This makes it possible to produce phosphate compounds with extremely high production efficiency and reduced production costs.

<Phosphate Compounds>
The phosphate compound is represented by the following chemical formula (D).

In the formula (D), ^X1 and ^X2 represent the same functional groups as those in the formula (A), and therefore, detailed explanations thereof will be omitted.

In the above chemical formula (D), M' represents a hydrogen atom, an alkali metal, an alkaline earth metal, a primary hydrocarbon group having 1 to 10 carbon atoms, a secondary hydrocarbon group having 1 to 10 carbon atoms, a primary hydrocarbon group having 1 to 10 carbon atoms and at least one of a halogen atom, a heteroatom, or an unsaturated bond (hereinafter referred to as a "primary hydrocarbon group having a halogen atom, etc."), or a secondary hydrocarbon group having 1 to 10 carbon atoms and at least one of a halogen atom, a heteroatom, or an unsaturated bond (hereinafter referred to as a "secondary hydrocarbon group having a halogen atom, etc.").

The alkali metals in M' include Li, Na, K, Rb, and Cs. Of these alkali metals, Li, Na, and K are preferred from the viewpoint of availability.

The alkaline earth metal in M' is not particularly limited, and examples include Be, Mg, Ca, Sr, and Ba. Among these alkaline earth metals, Mg, Ca, and Ba are preferred from the viewpoints of availability and safety.

The primary hydrocarbon group having 1 to 10 carbon atoms in M' is not particularly limited, and examples thereof include primary alkyl groups. The secondary hydrocarbon group having 1 to 10 carbon atoms is not particularly limited, and examples thereof include secondary alkyl groups. The primary alkyl group having 1 to 10 carbon atoms and the secondary alkyl group having 1 to 10 carbon atoms are not particularly limited, and examples thereof include methyl, ethyl, propyl, butyl, isopropyl, n-butyl, pentyl, hexyl, heptyl, and octyl chain alkyl groups, and cyclopentyl and cyclohexyl chain alkyl groups. The primary hydrocarbon group having 1 to 10 carbon atoms in M' is preferably a primary hydrocarbon group having 1, 2, 3, 4, 5, or 6 carbon atoms, and more preferably a primary hydrocarbon group having 1, 2, or 3 carbon atoms. In addition, the secondary hydrocarbon group having 1 to 10 carbon atoms in M' is preferably a secondary hydrocarbon group having 1, 2, 3, 4, 5, or 6 carbon atoms, and more preferably a secondary hydrocarbon group having 1, 2, or 3 carbon atoms.

In the above M', the primary hydrocarbon group having a carbon number of 1 to 10 and having a halogen atom or the like, and the secondary hydrocarbon group having a carbon number of 1 to 10 and having a halogen atom or the like are not particularly limited, and examples thereof include 2-iodoethyl group, 2-bromoethyl group, 2-chloroethyl group, 2-fluoroethyl group, 1,2-diiodoethyl group, 1,2-dibromoethyl group, 1,2-dichloroethyl group, 1,2-difluoroethyl group, 2,2-diiodoethyl group, 2,2-dibromoethyl group, 2,2-dichloroethyl group, 2,2-difluoroethyl group, 2,2,2-tribromoethyl group, 2,2,2-trichloroethyl group, and the like. chain-like halogenated alkyl groups such as a 2,2,2-trifluoroethyl group and a hexafluoro-2-propyl group; cyclic halogenated alkyl groups such as a 2-iodocyclohexyl group, a 2-bromocyclohexyl group, a 2-chlorocyclohexyl group and a 2-fluorocyclohexyl group; chain-like alkenyl groups such as a 2-propenyl group, a 2-butenyl group and a 3-butenyl group; cyclic alkenyl groups such as a 2-cyclopentenyl group, a 2-cyclohexenyl group and a 3-cyclohexenyl group; chain-like alkynyl groups such as a 2-propynyl group, a 2-butynyl group, a 3-butynyl group, a 2-pentynyl group, a 3-pentynyl group and a 4-pentynyl group. In the above M', the primary hydrocarbon group having a halogen atom or the like and having a carbon number in the range of 1 to 10 is preferably a primary hydrocarbon group having a halogen atom or the like and having a carbon number of 1, 2, 3, 4, 5, or 6, and more preferably a primary hydrocarbon group having a halogen atom or the like and having a carbon number of 1, 2, or 3. In addition, in the above M', the secondary hydrocarbon group having a halogen atom or the like and having a carbon number in the range of 1 to 10 is preferably a secondary hydrocarbon group having a halogen atom or the like and having a carbon number of 1, 2, 3, 4, 5, or 6, and more preferably a secondary hydrocarbon group having a halogen atom or the like and having a carbon number of 1, 2, or 3.

The unsaturated bond in M' means, for example, a carbon-carbon double bond or a triple bond.

More specifically, the phosphoric acid compound represented by the chemical formula (D) is preferably a phosphoric acid diester in which ^X1 and ^X2 are each independently an alkoxy group having 1 to 10 carbon atoms and M ^' is a hydrogen atom, a fluorophosphoric acid ester in which one of ^X1 and ^X2 is a fluorine atom and the other is an alkoxy group having 1 to 10 carbon atoms and M' is a hydrogen atom, or a difluorophosphoric acid in which ^X1 and ^X2 are fluorine atoms and M' is a hydrogen atom.

Specific examples of the phosphoric acid compound represented by the chemical formula (D) include, for example, dimethyl phosphate, diethyl phosphate, dipropyl phosphate, dibutyl phosphate, dipentyl phosphate, dihexyl phosphate, diphenyl phosphate, diallyl phosphate, dipropargyl phosphate, bis(2-butoxyethyl)phosphate, bis(2-chloroethyl)phosphate, bis(2,2,2-trifluoroethyl)phosphate, bis(1,1,1,3,3,3-hexafluoro-2-propyl)phosphate, methyl fluoro phosphate, ethyl fluorophosphate, propyl fluorophosphate, butyl fluorophosphate, pentyl fluorophosphate, hexyl fluorophosphate, phenyl fluorophosphate, allyl fluorophosphate, propargyl fluorophosphate, 2-butoxyethyl fluorophosphate, 2-chloroethyl fluorophosphate, 2,2,2-trifluoroethyl fluorophosphate, 1,1,1,3,3,3-hexafluoro-2-propyl fluorophosphate, difluorophosphoric acid, etc. However, the phosphoric acid compound represented by the chemical formula (D) is not limited to these compound groups.

<Silicon Compounds>
The silicon compound is represented by the following chemical formula (E).

In the chemical formula (E), X ³ to X ⁵ represent the same functional groups as those in the chemical formula (A), and therefore, detailed explanations thereof will be omitted.

The above-mentioned ^X7 is a leaving group, and represents a halogen atom, an alkoxy group having 1 to 10 carbon atoms, a haloacyloxy group, or a sulfonyloxy group.

Examples of the halogen atom in ^X7 include fluorine, chlorine, bromine, and iodine atoms. Among these halogen atoms, a chlorine atom, a bromine atom, and an iodine atom are preferred from the viewpoints of high elimination ability and reuse of by-products.

The alkoxy group having 1 to 10 carbon atoms in ^X7 is not particularly limited, and examples thereof include linear alkoxy groups such as methoxy group, ethoxy group, propoxy group, butoxy group, pentoxy group, and hexoxy group, cyclic alkoxy groups such as cyclopentoxy group, cyclohexoxy group, phenoxy group, 3-methylphenoxy group, 4-methylphenoxy group, 3,5-dimethylphenoxy group, etc. The alkoxy group having 1 to 10 carbon atoms in ^X7 is preferably an alkoxy group having 1, 2, 3, 4, 5, or 6 carbon atoms, and more preferably an alkoxy group having 1, 2, or 3 carbon atoms.

The haloacyloxy group in ^X7 is not particularly limited, but is preferably a functional group having 1 to 7 carbon atoms and having one or more hydrogen atoms substituted with a halogen atom. Specific examples include an iodoacetyl group, a bromoacetyl group, a chloroacetyl group, a fluoroacetyl group, a diiodoacetyl group, a dibromoacetyl group, a dichloroacetyl group, a difluoroacetyl group, a triiodoacetyl group, a tribromoacetyl group, a trichloroacetyl group, a trifluoroacetyl group, a 3,3,3-triiodopropanoyl group, a 3,3,3-tribromopropanoyl group, a 3,3,3-trichloropropanoyl group, a 3,3,3-trifluoropropanoyl group, a pentaiodopropanoyl group, a pentabromopropanoyl group, a pentachloropropanoyl group, a pentafluoropropanoyl group, a 4,4,4- Examples of the halogen atom include a triiodobutanoyl group, a 4,4,4-tribromobutanoyl group, a 4,4,4-trichlorobutanoyl group, a 4,4,4-trifluorobutanoyl group, a 3,3,4,4,4-pentaiodobutanoyl group, a 3,3,4,4,4-pentabromobutanoyl group, a 3,3,4,4,4-pentachlorobutanoyl group, a 3,3,4,4,4-pentafluorobutanoyl group, a heptaiodobutanoyl group, a heptabromobutanoyl group, a heptachlorobutanoyl group, a heptafluorobutanoyl group, a pentaiodobenzoyl group, a pentabromobenzoyl group, a pentachlorobenzoyl group, a pentafluorobenzoyl group, etc. The halogen atom represents fluorine, chlorine, bromine, and iodine.

The sulfonyloxy group in ^X7 is represented by a _-SO3Y group, where Y represents a halogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a hydrocarbon group having 1 to 10 carbon atoms and having at least one of a halogen atom, a heteroatom, or an unsaturated bond.

The halogen atoms in Y include fluorine, chlorine, bromine, and iodine atoms.

The hydrocarbon group having 1 to 10 carbon atoms in Y is not particularly limited, and examples thereof include linear alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, and octyl, and cyclic alkyl groups such as cyclopentyl and cyclohexyl. The hydrocarbon group having 1 to 10 carbon atoms in Y is preferably a hydrocarbon group having 1, 2, 3, 4, 5, or 6 carbon atoms, and more preferably a hydrocarbon group having 1, 2, or 3 carbon atoms.

The hydrocarbon group having a halogen atom and a carbon number of 1 to 10 in Y means a functional group in which some or all of the hydrogen atoms in the hydrocarbon group are replaced with halogen atoms. The halogen atoms represent fluorine, chlorine, bromine, and iodine atoms. The hydrocarbon group having a halogen atom and a carbon number of 1 to 10 in Y is preferably a hydrocarbon group having a halogen atom with a carbon number of 1, 2, 3, 4, 5, or 6, and more preferably a hydrocarbon group having a halogen atom with a carbon number of 1, 2, or 3.

The hydrocarbon group having a heteroatom with 1 to 10 carbon atoms in Y means a functional group in which some or all of the hydrogen and carbon in the hydrocarbon group are replaced with a heteroatom. The heteroatom represents an atom such as oxygen, nitrogen, or sulfur. The hydrocarbon group having a heteroatom with 1 to 10 carbon atoms in Y is preferably a hydrocarbon group having a heteroatom with 1, 2, 3, 4, 5, or 6 carbon atoms, and more preferably a hydrocarbon group having a heteroatom with 1, 2, or 3 carbon atoms.

The hydrocarbon group for Y having 1 to 10 carbon atoms and an unsaturated bond means, for example, a hydrocarbon group having 1 to 10 carbon atoms and a double bond or triple bond between carbon atoms. Furthermore, the hydrocarbon group having an unsaturated bond is preferably a hydrocarbon group having 1, 2, 3, 4, or 5 unsaturated bonds, and more preferably a hydrocarbon group having 1, 2, or 3 unsaturated bonds.

Specific examples of the hydrocarbon group having a carbon number of 1 to 10 and having a halogen atom, a heteroatom, or an unsaturated bond in Y include, for example, an iodomethyl group, a bromomethyl group, a chloromethyl group, a fluoromethyl group, a diiodomethyl group, a dibromomethyl group, a dichloromethyl group, a difluoromethyl group, a triiodomethyl group, a tribromomethyl group, a trichloromethyl group, a trifluoromethyl group, a 2-iodoethyl group, a 2-bromoethyl group, a 2-chloroethyl group, a 2-fluoroethyl group, a 1,2-diiodoethyl group, a 1,2-dibromoethyl group, a 1,2-dichloroethyl group, a 1,2-difluoroethyl group, a 2,2-diiodoethyl group, a 2,2 -chain halogenated alkyl groups such as dibromoethyl group, 2,2-dichloroethyl group, 2,2-difluoroethyl group, 2,2,2-tribromoethyl group, 2,2,2-trichloroethyl group, 2,2,2-trifluoroethyl group, and hexafluoro-2-propyl group; cyclic halogenated alkyl groups such as 2-iodocyclohexyl group, 2-bromocyclohexyl group, 2-chlorocyclohexyl group, and 2-fluorocyclohexyl group; chain alkenyl groups such as ethenyl group, 2-propenyl group, isopropenyl group, 2-butenyl group, and 3-butenyl group; cyclic alkenyl groups such as 2-cyclopentenyl group, 2-cyclohexenyl group, and 3-cyclohexenyl group. chain-like alkynyl groups such as ethynyl, 2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, 1-pentynyl, 2-pentynyl, 3-pentynyl, and 4-pentynyl groups; aryl groups such as phenyl, 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 2,6-dimethylphenyl, 3,5-dimethylphenyl, 2,4,6-trimethylphenyl, 2-nitrophenyl, 4-nitrophenyl, 2,4-dinitrophenyl, and 2,6-dinitrophenyl groups; 2-iodophenyl, 2-bromophenyl, 2-chlorophenyl, 2-fluorophenyl, and 3-iodophenyl groups; Examples of halogenated aryl groups include 3-bromophenyl, 3-chlorophenyl, 3-fluorophenyl, 4-iodophenyl, 4-bromophenyl, 4-chlorophenyl, 4-fluorophenyl, 2,6-diiodophenyl, 2,6-dibromophenyl, 2,6-dichlorophenyl, 2,6-difluorophenyl, 3,5-diiodophenyl, 3,5-dibromophenyl, 3,5-dichlorophenyl, 3,5-difluorophenyl, pentaiodophenyl, pentabromophenyl, pentachlorophenyl and pentafluorophenyl groups; and naphthyl groups such as 1-naphthyl and 2-naphthyl groups.

More specifically, the silicon compound represented by the chemical formula (E) is preferably a trialkylsilyl halide in which ^X3 to ^X5 are each independently a hydrocarbon group having 1 to 6 carbon atoms and ^X7 is a halogen atom.

Specific examples of silicon compounds represented by the chemical formula (E) include, for example, chlorodimethylsilane, chlorotrimethylsilane, chloro(ethyl)dimethylsilane, chlorotriethylsilane, diisopropylchlorosilane, chlorotriisopropylsilane, tributylchlorosilane, tert-butyldimethylchlorosilane, chlorodimethylisopropylsilane, chlorodimethylvinylsilane, chlorodiethylisopropylsilane, chlorodimethylpropylsilane, allylchlorodimethylsilane, butylchlorodimethylsilane, chloro(hexyl)dimethylsilane, chlorotrihexylsilane, chloro(cyclohexyl)dimethylsilane, chlorodimethylphenylsilane, benzylchlorodimethylsilane, diphenylmethylchlorosilane, chlorotriphenylsilane, chloro(methyl)(phenyl)(vinyl)silane, and chloro(methyl)diphenylsilane. However, the silicon compounds represented by the chemical formula (E) are not limited to these compound groups.

<Reaction conditions for step (II)>
The reaction molar ratio of the step (II) is not particularly limited, and can be appropriately set according to the reaction species.In the reaction molar ratio of phosphoric acid compound and silicon compound, the lower limit of silicon compound is usually 1 mole or more per 1 mole of phosphoric acid compound.In addition, the upper limit of phosphoric acid compound is 5 moles or less, and from the viewpoint of industrial production, it is preferably 2.5 moles or less, more preferably 1.5 moles or less.

The reaction initiation temperature in step (II) is not particularly limited as long as the reaction proceeds, and may be set appropriately depending on the type of reaction. The lower limit of the reaction initiation temperature is usually 0°C or higher, and from the viewpoint of reactivity, it is preferably 20°C or higher, and more preferably 40°C or higher. The upper limit of the reaction initiation temperature is usually 150°C or lower, and from the viewpoint of reactivity, it is preferably 120°C or lower, and more preferably 100°C or lower. By setting the lower limit of the reaction initiation temperature to 0°C or higher, it is possible to prevent the reaction rate from significantly decreasing. On the other hand, by setting the upper limit of the reaction initiation temperature to 150°C or lower, it is possible to suppress the excess energy used in the reaction.

The means for adjusting the reaction initiation temperature is not particularly limited. For example, when controlling the reaction initiation temperature by cooling so that it is within the above-mentioned temperature range, this can be done by ice-cooling the reaction vessel into which the phosphoric acid compound and silicon compound are added. Also, when controlling the reaction initiation temperature by heating so that it is within the above-mentioned temperature range, this can be done by using an oil bath set to any desired temperature.

The reaction time in step (II) is not particularly limited and may be set appropriately depending on the reactant species. The lower limit of the reaction time is usually 1 hour or more. The upper limit of the reaction time is usually 12 hours or less, and from the viewpoint of industrial production, 6 hours or less is preferable, and 3 hours or less is more preferable.

The reaction in step (II) can be carried out without a solvent or in a non-aqueous solvent. When the reaction in step (II) is carried out without a solvent, the silicon compound also functions as a reaction solvent.

The nonaqueous solvent may be the same as the nonaqueous solvent described in step (I). Therefore, details are omitted.

The lower limit of the amount of the non-aqueous solvent used is preferably 1 mole or more, more preferably 10 moles or more, per mole of the phosphoric acid compound. The upper limit of the amount of the non-aqueous solvent used is preferably 10,000 moles or less, more preferably 1,000 moles or less, and even more preferably 100 moles or less, per mole of the phosphoric acid compound. By setting the lower limit of the amount of the non-aqueous solvent to 1 mole or more, it is possible to prevent a decrease in the reactivity between the phosphoric acid compound and the silicon compound, and to suppress a decrease in the yield and purity of the phosphoric acid silyl ester. On the other hand, by setting the upper limit of the amount of the non-aqueous solvent used to 10,000 moles or less, it is possible to suppress the energy required for distilling off the non-aqueous solvent, and to prevent it from becoming disadvantageous in industrial production.

The phosphate ester obtained in step (II) may be isolated and purified depending on its purity. The method is not particularly limited, and any known method can be used. Specific examples include atmospheric distillation, reduced pressure distillation, filtration, filtration, recrystallization, sublimation purification, silica gel column chromatography, preparative thin layer chromatography (PTLC), high performance liquid chromatography (HPLC), and ion chromatography (IC).

The following is a detailed description of preferred embodiments of the present invention. However, unless otherwise specified, the materials and amounts of ingredients described in the embodiments are not intended to limit the scope of the present invention.

In the following examples, the purity was determined and the physicochemical properties were measured using the following equipment:

(purity)
The purity of the phosphate compound was calculated from anion analysis by ion chromatography. The analytical device and measurement conditions are as follows:
Apparatus: 850 Professional IC Anion (manufactured by Metrohm)
Column: Dionex IonPac AS23 2x250mm
(Manufactured by Thermo Fisher Scientific)
Sample: 100 ppm sample aqueous solution Flow rate: 1 mL/min
Eluent: 4.5 mM Na ₂ CO ₃ in H ₂ O-acetonitrile (7:3) mixture

(NMR Measurement)
Tabletop nuclear magnetic resonance spectrometer: Spinsolve 60 ULTRA Phosphorus
(Made by Magritek)

Example 1
<Sodium ethyl (2,2,2-trifluoroethyl)phosphate (without solvent)>
Sodium iodide (630 mg, 4.20 mmol, Fujifilm Wako Pure Chemical Industries, Ltd.) was placed as a raw salt in a 50 mL eggplant-shaped flask containing a stirrer, and then diethyl 2,2,2-trifluoroethyl phosphate (1.18 g, 5.00 mmol) as a phosphate ester was added at room temperature. This mixed solution was heated at 120° C. for 4 hours under a nitrogen stream. After the reaction mixture was allowed to cool to room temperature, the reaction mixture was filtered and the residue was dried overnight at 120° C. under a nitrogen stream to obtain white solid sodium ethyl (2,2,2-trifluoroethyl) phosphate (930 mg, 96.1%) as a phosphate compound. The purity of sodium ethyl (2,2,2-trifluoroethyl) phosphate was 99.6%.

Example 2
<Bis(2,2,2-trifluoroethyl)copper(II)phosphate (without solvent)>
Copper chloride (II) (980 mg, 7.29 mmol, manufactured by Wako Pure Chemical Industries, Ltd.) was placed as a raw material salt in a 100 mL eggplant-shaped flask containing a stirrer, and then tris(2,2,2-trifluoroethyl)phosphate (50.0 g, 145 mmol) as a phosphate ester was added at room temperature. This mixed solution was heated and refluxed for 6 hours at a water bath temperature of 155°C under a nitrogen stream. After the reaction mixture was allowed to cool to room temperature, it was filtered and the residue was dried overnight at 120°C under a nitrogen stream to obtain a pale blue solid bis(2,2,2-trifluoroethyl)copper(II)phosphate (4.06 g, 96.1%) as a phosphate compound. The purity of bis(2,2,2-trifluoroethyl)copper(II)phosphate was 98.4%.

Example 3
<1-Ethyl-3-methylimidazolium bis(2,2,2-trifluoroethyl)phosphate>
In a 50 mL eggplant-shaped flask containing a stirrer, 1-ethyl-3-methylimidazolium bromide (760 mg, 3.11 mmol, manufactured by TCI) was placed as a raw material salt, and then ethyl bis(2,2,2-trifluoroethyl)phosphate (905 mg, 3.12 mmol) as a phosphoric acid ester was added at room temperature. This mixed solution was heated at 120°C for 4 hours under a nitrogen stream. After the reaction mixture was allowed to cool to room temperature, it was concentrated using an evaporator, and the liquid was subsequently dried at 60°C for 1 hour to obtain colorless liquid 1-ethyl-3-methylimidazolium bis(2,2,2-trifluoroethyl)phosphate (1.49 g, quantitative) as a phosphate compound. The purity of 1-ethyl-3-methylimidazolium bis(2,2,2-trifluoroethyl)phosphate was 99.1%.

Example 4
<Synthesis of lithium bis(2,2,2-trifluoroethyl)phosphate (using non-aqueous solvent)>
Lithium chloride (0.634 g, 15.0 mmol) as a raw material salt and acetonitrile (40.0 g, 974 mmol, manufactured by Kishida Chemical Co., Ltd.) as an aprotic organic solvent were placed in a 50 mL eggplant-shaped flask containing a stirrer, and then bis(2,2,2-trifluoroethyl)trimethylsilylphosphate (5.00 g, 15.0 mmol) as a phosphate ester was added at room temperature. This mixed solution was heated and refluxed at 82°C for 2 hours under a nitrogen stream. The reaction mixture was allowed to cool to room temperature, and then further cooled to 0°C. The precipitate was filtered, and the residue was washed with a small amount of acetonitrile. The residue was dried at 45°C for 20 minutes using an evaporator to obtain white solid bis(2,2,2-trifluoroethyl)lithium phosphate (2.28 g, 56.9%) as a phosphate compound. The purity of bis(2,2,2-trifluoroethyl)lithium phosphate was 99.9%.

Example 5
<Synthesis of lithium difluorophosphate 1 (without solvent)>
Trimethylsilyl difluorophosphate (3.50 g, 20.1 mmol) as a phosphoric acid ester was added to a 50 mL eggplant-shaped flask containing a stirrer under nitrogen protection, and then lithium chloride (568 mg, 13.4 mmol) as a raw salt was added at room temperature. This mixture was heated at 80° C. for 1 hour under a nitrogen stream. After cooling to room temperature, the reaction mixture was filtered and the residue was washed with a small amount of DMC (dimethyl carbonate). The residue was dried at 120° C. for 15 minutes using a dryer to obtain white solid lithium difluorophosphate (920 mg, 63.6%) as a phosphate compound. The purity of lithium difluorophosphate was 99.5%.

Example 6
<Synthesis of lithium difluorophosphate 2 (using non-aqueous solvent)>
Trimethylsilyl difluorophosphate (50.0 g, 287 mmol) as a phosphoric acid ester was added to a 500 mL eggplant-shaped flask containing a stirrer under nitrogen protection, and then diluted with acetonitrile (150 g, 3.65 mol, manufactured by Kishida Chemical Co., Ltd.) as an aprotic organic solvent. Furthermore, lithium chloride (11.8 g, 278 mmol) as a raw material salt was added at room temperature. This mixture was heated and refluxed at 82° C. for 5 hours under a nitrogen stream. After cooling to room temperature, the reaction mixture was concentrated using an evaporator, and the resulting residue was filtered and washed with a small amount of DMC (dimethyl carbonate). The residue was dried at 120° C. for 1 hour using a dryer to obtain white solid lithium difluorophosphate (27.4 g, 91.4%) as a phosphate compound. The purity of the lithium difluorophosphate was 99.4%.

(Example 7)
<Synthesis of bis(2,2,2-trifluoroethyl)trimethylsilyl phosphate (without solvent)>
In a 50 mL eggplant-shaped flask containing a stirrer, chlorotrimethylsilane (16.6 g, 153 mmol, manufactured by TCI) was placed as a silicon compound, and then bis(2,2,2-trifluoroethyl)phosphate (20.0 g, 76.3 mmol) as a phosphoric acid compound was added at room temperature. This mixed solution was heated and refluxed at 80° C. for 6 hours under a nitrogen stream. Excess chlorotrimethylsilane was removed from the reaction mixture using an evaporator to obtain colorless liquid bis(2,2,2-trifluoroethyl)trimethylsilylphosphate (21.2 g, 83.1%) as a phosphoric acid ester. The purity of bis(2,2,2-trifluoroethyl)trimethylsilylphosphate was 99.7%.

The physicochemical properties of the obtained bis(2,2,2-trifluoroethyl)trimethylsilyl phosphate are as follows:
¹ H-NMR (CDCl ₃ , δ ppm): -0.06 (s, 9H), 4.02 (dq, 4H, J _H-F = J _H-P = 8.3 Hz);
¹⁹ F-NMR (CDCl ₃ , δ ppm): -74.8 (t, 6F, J _HF =8.3 Hz).
³¹ P-NMR (CDCl ₃ , δ ppm): -10.1 (tt, 1P, J _H-P = 8.3 Hz).

(Example 8)
<Synthesis of trimethylsilyl difluorophosphate 1 (without solvent)>
In a 200 mL eggplant flask containing a stirrer, chlorotrimethylsilane (48.7 g, 448 mmol, manufactured by TCI) as a silicon compound was placed, and difluorophosphoric acid (45.7 g, 448 mmol) as a phosphoric acid compound was added dropwise at room temperature. The mixed solution was stirred at 50° C. for 6 hours under a nitrogen stream. The reaction mixture was distilled at atmospheric pressure to obtain colorless liquid trimethylsilyl difluorophosphate (49.0 g, 62.7%) as a phosphoric acid ester. The purity of trimethylsilyl difluorophosphate was 95.6%.

Example 9
<Synthesis of trimethylsilyl difluorophosphate 2 (recycling of by-product chlorotrimethylsilane, without solvent)>
In a 50 mL eggplant-shaped flask containing a stirrer, chlorotrimethylsilane {7.16 g, 65.9 mmol} as a silicon compound was added, and then difluorophosphoric acid (6.71 g, 65.8 mmol) as a phosphoric acid compound was added dropwise at room temperature. The mixed solution was stirred at 50° C. for 3 hours under a nitrogen stream. The reaction mixture was distilled at normal pressure to obtain colorless liquid trimethylsilyl difluorophosphate (7.12 g, 62.2%) as a phosphoric acid ester. The purity of trimethylsilyl difluorophosphate was 96.1%. In addition, as chlorotrimethylsilane, a by-product (by-product (E') of step (I)) produced during the synthesis of lithium difluorophosphate in Example 5 was used.

The physicochemical properties of the obtained trimethylsilyl difluorophosphate are as follows:
¹ H-NMR (CDCl ₃ , δ ppm): 0.33 (s, 9H);
^19F -NMR (CDCl ₃ , δ ppm): -80.4 (d, 2F, J = 985.9Hz);
³¹ P-NMR (CDCl ₃ , δ ppm): -29.1 (dd, 1P, J=985.9Hz).

Example 10
<Synthesis of dimethylvinylsilyl difluorophosphate (without solvent)>
In a 100 mL eggplant flask containing a stirrer, chlorodimethylvinylsilane (10.1 g, 83.7 mmol, manufactured by TCI) was placed as a silicon compound, and then difluorophosphoric acid (8.14 g, 79.8 mmol) as a phosphoric acid compound was added dropwise at room temperature. The mixed solution was stirred at 60° C. for 3 hours under a nitrogen stream. Dimethylvinylsilyl difluorophosphate (2.33 g, 15.7%) was obtained as a colorless liquid phosphoric acid ester by vacuum distillation of the reaction mixture. The purity of the dimethylvinylsilyl difluorophosphate was 97.9%.

The physicochemical properties of the obtained dimethylvinylsilyl difluorophosphate are as follows:
¹ H-NMR (CDCl ₃ , δ ppm): 0.44 (s, 7H), 6.02-6.13 (m, 2H);
¹⁹ F-NMR (CDCl ₃ , δ ppm): -80.0 (d, 2F, J = 990.3 Hz);
³¹ P-NMR (CDCl ₃ , δ ppm): -28.4 (dd, 1P, J=990.3Hz).

(Example 11)
<Synthesis of dimethylphenylsilyl difluorophosphate (without solvent)>
In a 100 mL eggplant flask containing a stirrer, chlorodimethylphenylsilane (16.8 g, 98.4 mmol, manufactured by TCI) as a silicon compound was placed, and then difluorophosphoric acid (10.1 g, 99.0 mmol) as a phosphoric acid compound was added dropwise at room temperature. The mixed solution was stirred at 60° C. for 3 hours under a nitrogen stream. Dimethylphenylsilyl difluorophosphate (10.6 g, 45.6%) was obtained as a colorless liquid phosphoric acid ester by vacuum distillation of the reaction mixture. The purity of the dimethylphenylsilyl difluorophosphate was 97.5%.

The physicochemical properties of the obtained dimethylphenylsilyl difluorophosphate are as follows:
¹ H-NMR (CDCl ₃ , δ ppm): 0.37 (s, 6H), 7.07-7.47 (m, 5H);
^19F -NMR (CDCl ₃ , δ ppm): -79.7 (d, 2F, J = 991.4Hz);
³¹ P-NMR (CDCl ₃ , δ ppm): -30.0 (dd, 1P, J=991.4Hz).

Example 12
<Synthesis of triethylsilyl difluorophosphate (without solvent)>
In a 50 mL eggplant-shaped flask containing a stirrer, chlorotriethylsilane (10.0 g, 66.3 mmol, manufactured by TCI) as a silicon compound was placed, and difluorophosphoric acid (6.69 g, 65.6 mmol) as a phosphoric acid compound was added dropwise at room temperature. The mixed solution was stirred at 60° C. for 4 hours under a nitrogen stream. The reaction mixture was distilled under reduced pressure to obtain colorless liquid triethylsilyl difluorophosphate (7.29 g, 51.4%) as a phosphoric acid ester. The purity of triethylsilyl difluorophosphate was 98.3%.

The physicochemical properties of the obtained triethylsilyl difluorophosphate are as follows:
¹ H-NMR (CDCl ₃ , δ ppm): 0.40-1.11 (m, 15H);
^19F -NMR (CDCl ₃ , δ ppm): -80.9 (d, 2F, J = 986.4Hz);
³¹ P-NMR (CDCl ₃ , δ ppm): -29.5 (dd, 1P, J=986.4Hz).

(Example 13)
<Synthesis of cyclohexyldimethylsilyl difluorophosphate (without solvent)>
In a 50 mL eggplant flask containing a stirrer, chloro(cyclohexyl)dimethylsilane (12.0 g, 67.9 mmol, manufactured by TCI) was placed as a silicon compound, and then difluorophosphoric acid (6.83 g, 67.0 mmol) as a phosphoric acid compound was added dropwise at room temperature. The mixed solution was stirred at 60° C. for 4 hours under a nitrogen stream. The reaction mixture was distilled under reduced pressure to obtain colorless liquid cyclohexyldimethylsilyl difluorophosphate (9.92 g, 61.0%) as a phosphoric acid ester. The purity of cyclohexyldimethylsilyl difluorophosphate was 93.6%.

The physicochemical properties of the obtained cyclohexyldimethylsilyl difluorophosphate are as follows:
¹ H-NMR (CDCl ₃ , δ ppm): 0.29 (s, 6H), 0.92-1.67 (br m, 11H);
^19F -NMR (CDCl ₃ , δ ppm): -79.8 (d, 2F, J = 989.0Hz);
³¹ P-NMR (CDCl ₃ , δ ppm): -29.5 (dd, 1P, J=989.0Hz).

(Example 14)
<Synthesis of dimethylphenylsilyl difluorophosphate (using non-aqueous solvent)>
Sodium difluorophosphate (5.01 g, 40.4 mmol) as a phosphoric acid compound and acetonitrile (20.0 g, 487 mmol, manufactured by Kishida Chemical Co., Ltd.) as an aprotic organic solvent were added to a 50 mL screw vial containing a stirrer under nitrogen protection, and then chlorodimethylphenylsilane (6.82 g, 40.0 mmol, manufactured by TCI Co., Ltd.) as a silicon compound was added dropwise at room temperature. The mixed solution was stirred at 60° C. for 2 hours under a nitrogen atmosphere. After cooling to room temperature, the reaction mixture was filtered using a 0.45 μm membrane filter. The filtrate was bubbled with nitrogen gas for 12 hours to remove acetonitrile. The residue was filtered using a 0.45 μm membrane filter to obtain a colorless liquid dimethylphenylsilyl difluorophosphate (7.79 g, 82.5%) as a phosphoric acid ester. The purity of dimethylphenylsilyl difluorophosphate was 95.4%.

(Example 15)
<Synthesis of triisopropylsilyl difluorophosphate (using non-aqueous solvent)>
Sodium difluorophosphate (2.02 g, 16.3 mmol) as a phosphoric acid compound and acetonitrile (9.13 g, 222 mmol, manufactured by Kishida Chemical Co., Ltd.) as an aprotic organic solvent were added to a 50 mL screw vial containing a stirrer under nitrogen protection, and then chlorotriisopropylsilane (3.14 g, 16.3 mmol, manufactured by TCI Co., Ltd.) as a silicon compound was added dropwise at room temperature. The mixed solution was stirred at 60° C. for 2 hours under a nitrogen atmosphere. After cooling to room temperature, the reaction mixture was filtered using a 0.45 μm membrane filter. Nitrogen gas was bubbled through the filtrate for 12 hours to remove acetonitrile. The residue was filtered using a 0.45 μm membrane filter to obtain colorless liquid triisopropylsilyl difluorophosphate (1.00 g, 23.7%) as a phosphoric acid ester. The purity of triisopropylsilyl difluorophosphate was 97.4%.

The physicochemical properties of the obtained triisopropylsilyl difluorophosphate are as follows:
¹ H-NMR (CDCl ₃ , δ ppm): 0.98-1.27 (m, 21H);
^19F -NMR (CDCl ₃ , δ ppm): -80.4 (d, 2F, J = 983.5Hz);
³¹ P-NMR (CDCl ₃ , δ ppm): -29.5 (dd, 1P, J=989.0Hz).

(Example 16)
<Synthesis of methyldiphenylsilyl difluorophosphate (using non-aqueous solvent)>
Sodium difluorophosphate (3.01 g, 24.3 mmol) as a phosphoric acid compound and acetonitrile (10.0 g, 244 mmol, Kishida Chemical Co., Ltd.) as an aprotic organic solvent were added to a 50 mL screw vial containing a stirrer under nitrogen protection, and then chloro(methyl)diphenylsilane (5.36 g, 23.0 mmol, TCI Co., Ltd.) as a silicon compound was added dropwise at room temperature. The mixed solution was stirred at 60° C. for 11 hours under a nitrogen atmosphere. After cooling to room temperature, the reaction mixture was filtered using a 0.45 μm membrane filter. Nitrogen gas was bubbled through the filtrate for 12 hours to remove acetonitrile. The residue was filtered using a 0.45 μm membrane filter to obtain a colorless liquid methyldiphenylsilyl difluorophosphate (5.22 g, 76.1%) as a phosphoric acid ester. The purity of methyldiphenylsilyl difluorophosphate was 88.0%.

The physicochemical properties of the obtained methyldiphenylsilyl difluorophosphate are as follows:
¹ H-NMR (CDCl ₃ , δ ppm): 0.92 (s, 3H), 7.29-7.73 (m, 10H);
^19F -NMR (CDCl ₃ , δ ppm): -78.8 (d, 2F, J = 995.6Hz);
³¹ P-NMR (CDCl ₃ , δ ppm): -30.3 (dd, 1P, J=995.6Hz).

Claims (11)

A method for producing a phosphate compound, comprising at least a step (I) of reacting a phosphate ester represented by the following chemical formula (A) with a starting salt represented by the following chemical formula (B) to produce a phosphate compound represented by the following chemical formula (C).

[In the formula, Z represents a silicon atom. ^X1 and ^X2 each independently represent a halogen atom, a hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a hydrocarbon group having 1 to 10 carbon atoms and having a halogen atom, or an alkoxy group having 1 to 10 carbon atoms and having a halogen atom. ^X3 to ^X5 each independently represent a halogen atom , a hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a hydrocarbon group having 1 to 10 carbon atoms and having a halogen atom, or an alkoxy group having 1 to 10 carbon atoms and having a halogen atom, and at least one of ^X3 to ^X5 is either the hydrocarbon group having 1 to 10 carbon atoms or the alkoxy group having 1 to 10 carbon atoms.]

[In the formula, M represents an alkali metal , a transition metal, or an imidazolium . ^X6 represents a halogen atom. n represents a natural number from 1 to 4.]

[In the formula, M is the same as in the chemical formula (B). ^X1 and ^X2 represent the same functional groups as in the chemical formula (A). n represents the same valence as in the chemical formula (B).] 2. A method for producing a phosphate compound according to claim 1, comprising: a step (II) of reacting a phosphate compound represented by the following chemical formula (D) with a silicon compound represented by the following chemical formula (E) to produce a phosphate silyl ester represented by the following chemical formula (F).

[In the formula, M′ represents a hydrogen atom or an alkali metal. ^X1 and ^X2 represent the same functional groups as those in the chemical formula (A). n represents the same valence as that in the chemical formula (B).]

[In the formula, X ³ to X ⁵ represent the same functional groups as those in the chemical formula (A). X ⁷ is a leaving group and represents a halogen atom.]

[In the formula, X ¹ to X ⁵ represent the same functional groups as those in the chemical formula (A).] The method for producing a phosphate compound according to claim 2, wherein the silicon compound represented by the chemical formula (E) is a by-product produced in the step (I). The method for producing a phosphate compound according to claim 2 or 3, wherein the phosphate compound is a phosphate diester in which ^X1 and ^X2 in the chemical formula (D) are each independently an alkoxy group having 1 to 10 carbon atoms, and M ^' is a hydrogen atom. The method for producing a phosphate compound according to claim 2 or ³ , wherein the phosphate compound is a fluorophosphoric acid ester in which one of ^X1 and X2 in the chemical formula (D) is a fluorine atom, the other is an alkoxy group having 1 to 10 carbon atoms, and M' is a hydrogen atom. The method for producing a phosphate compound according to claim 2 or 3, wherein the phosphate compound is a difluorophosphoric acid in which ^X1 and ^X2 in the chemical formula (D) are fluorine atoms and M' is a hydrogen atom. The method for producing a phosphate compound according to any one of claims ² to ⁶ , wherein the silicon compound is a trialkylsilyl halide in which X3 to ^X5 in the chemical formula (E) are each independently a hydrocarbon group having 1 to 6 carbon atoms, and X7 is a halogen atom. 8. The method for producing a phosphate compound according to claim 1, wherein M in the chemical formula (B) is a lithium atom, a sodium atom, a magnesium atom , or 1-ethyl-3-methylimidazolium. The method for producing a phosphate compound according to any one of claims 2 to 8, wherein at least one of steps (I) and (II) is carried out in the absence of a solvent. The method for producing a phosphate compound according to any one of claims 2 to 8, wherein at least one of steps (I) and (II) is carried out in a non-aqueous solvent. The method for producing a phosphate compound according to claim 10, wherein the non-aqueous solvent is an aprotic organic solvent.