Method for obtaining onium salt and method for purifying onium salt

Abstract

To provide a method for producing an onium salt that does not contain carboxylic acid, or an onium salt in which a content of carboxylic acid is reduced to an extent capable of obtaining a sufficient solubility of cellulose relative to an onium salt.SOLUTION: A method for producing an onium salt, characterized by obtaining an onium salt from a mixture containing the onium salt and a carboxylic acid, comprises the following steps (1) and (2): Step (1): Adding an amine to a mixture containing the onium salt and carboxylic acid to produce an amine-carboxylate salt composed of the amine and the carboxylic acid. Step (2): Separating the onium salt from the amine-carboxylate salt produced in step (1) to obtain the onium salt.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing an onium salt and a method for purifying an onium salt. [Background technology]

[0002] Polysaccharides are substances formed by the polymerization of many monosaccharide molecules through glycosidic bonds. Among them, cellulose, a polysaccharide composed of β-glucose molecules, is the most abundant biomass resource on earth, and as an environmentally friendly material, research on dissolving and molding it has been widely conducted. However, cellulose has strong hydrogen bonds between and within its molecular chains, making it difficult to dissolve in general solvents.

[0003] Onium salts have been proposed as solvents for dissolving cellulose, and Patent Document 1 describes a method for dissolving cellulose using a molten ionic liquid consisting of a 1-alkyl-3-methylimidazolium cation and an acetate anion.

[0004] Patent Document 2 describes a method for producing a quaternary ammonium organic acid salt, which comprises producing a quaternary ammonium carbonate, mixing the produced quaternary ammonium carbonate with an organic acid, and carrying out anion exchange with the organic acid. The method describes a method for producing a quaternary ammonium organic acid salt, which comprises producing a quaternary ammonium carbonate using a nitrogen-containing heterocyclic aromatic compound such as N-methylimidazole or N-methylbenzimidazole as a raw material, mixing it with acetic acid as the organic acid, and carrying out anion exchange.

[0005] Patent Document 3 describes a method for producing a quaternary ammonium carboxylate, characterized by reacting a quaternary ammonium alkyl carbonate with a carboxylic acid, and in the examples, it describes the reaction of N,N-diethyl-N-(2-methoxyethyl)-N-methylammonium methyl carbonate with methoxyacetic acid to obtain N,N-diethyl-N-(2-methoxyethyl)-N-methylammonium methoxyacetate.

[0006] Non-Patent Document 1 describes a one-pot synthesis method for a mixture of 1,3-dialkylimidazolium acetate (when R1 and R2 are the same) and 1-alkyl-3-methylimidazolium acetate, 1,3-dialkylimidazolium acetate, and 1,3-dimethylimidazolium acetate (when R1 is a methyl group and R1 and R2 are different), as shown in the following scheme. It also describes that colored impurities are removed by passing the ionic liquid, such as imidazolium acetate, through a decolorizing charcoal column. [ka]

[0007] Non-Patent Document 2 describes a method for separating acetic acid from a synthetic mixture containing 1-ethyl-3-methylimidazolium acetate, which is an ionic liquid. The separation methods described include evaporating acetic acid as a volatile component from a mixture containing 1-ethyl-3-methylimidazolium acetate, extracting acetic acid with a solvent that is immiscible with 1-ethyl-3-methylimidazolium acetate, and adding methanol to a mixture containing 1-ethyl-3-methylimidazolium acetate to esterify acetic acid and then removing methyl acetate by distillation. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Special Publication No. 2005-506401 [Patent Document 2] Japanese Patent Publication No. 63-280045 [Patent Document 3] JP 2015-83545 A [Non-patent literature]

[0009] [Non-Patent Document 1] Pure Appl. Chem., Vol.84, No.3, pp.745-754, 2012 [Non-Patent Document 2] J. Chem. Eng. Data 2013, 58, 197-202 Summary of the Invention [Problem to be solved by the invention]

[0010] In the method for producing a quaternary ammonium carboxylate, which is an ionic liquid and an onium salt, described in the prior art, the carboxylic acid used remains in the quaternary ammonium carboxylate product. The remaining carboxylic acid forms an association with the produced quaternary ammonium carboxylate, and when the quaternary ammonium carboxylate containing the association is used to dissolve cellulose, the solubility of cellulose in the quaternary ammonium carboxylate decreases.

[0011] In the context of such prior art, an object of the present invention is to provide a method for producing an onium salt that does not contain a carboxylic acid, or an onium salt in which the carboxylic acid content is reduced to such an extent that sufficient solubility of cellulose in the onium salt can be obtained. Another object of the present invention is to provide a method for purifying an onium salt, which removes a carboxylic acid contained in the onium salt or reduces the content of the carboxylic acid to an extent that sufficient solubility of cellulose in the onium salt can be obtained. [Means for solving the problem]

[0012] The present inventors have conducted extensive research into a method for producing an onium salt that does not contain a carboxylic acid or an onium salt in which the carboxylic acid content is reduced to such an extent that sufficient solubility of cellulose in the onium salt is obtained, and a method for purifying the onium salt, and have completed the present invention.

[0013] That is, the present invention provides the following [1] to

[10] . [1] A method for producing an onium salt represented by formula (1), comprising obtaining an onium salt represented by formula (1) from a mixture containing an onium salt represented by formula (1) and a carboxylic acid represented by formula (3), the method comprising the steps (1) and (2): Formula (1): [ka] (In formula (1), A + represents pyridinium, ammonium or imidazolium; X - is a carboxylate anion represented by the following formula (2): Formula (2): [ka] (In formula (2), R 1 represents a hydrocarbon group having 1 to 12 carbon atoms, which may contain a heteroatom and / or a double bond. Formula (3): [ka] (In formula (3), R 1 is as defined above.) Process (1): A step of adding an amine to a mixture containing the onium salt represented by formula (1) and the carboxylic acid represented by formula (3) to produce an amine-carboxylate consisting of the amine and the carboxylic acid represented by formula (3). Process (2): A step of separating the onium salt represented by formula (1) from the amine-carboxylate produced in step (1) to obtain the onium salt represented by formula (1). [2] The method for producing an onium salt according to [1], wherein the amine added in the step (1) is an amine represented by the following formula (4): Formula (4): [ka] (In formula (4), R 3 , R 4 and R5 may be the same or different and are a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms, and the hydrocarbon group may contain a double bond and may contain a branched structure and / or a ring structure. 3 , R 4 and R 5 The total number of carbon atoms in each of these is 8 or more.) [3] The method for producing an onium salt according to [1], wherein the onium salt represented by the formula (1) is of at least two types. [4] The method for producing an onium salt according to [1], wherein the mixture containing the onium salt represented by the formula (1) and the carboxylic acid represented by the formula (3) further contains water and / or a hydrophilic solvent. [5] The method for producing an onium salt according to [1], wherein the amine added in the step (1) is an amine solution diluted with a solvent. [6] A method for purifying an onium salt represented by the following formula (1) by removing a carboxylic acid of the following formula (3) from a mixture containing the onium salt represented by the following formula (1) and a carboxylic acid of the following formula (3), the method comprising the following steps (1) and (2): Formula (1): [ka] (In formula (1), A + represents pyridinium, ammonium or imidazolium; X - is a carboxylate anion represented by the following formula (2): Formula (2): [ka] (In formula (2), R 1 represents a hydrocarbon group having 1 to 12 carbon atoms, which may contain a heteroatom and / or a double bond. Formula (3): [ka] (In formula (3), R1 is as defined above.) Process (1): A step of adding an amine to a mixture containing the onium salt represented by formula (1) and the carboxylic acid represented by formula (3) to produce an amine-carboxylate consisting of the amine and the carboxylic acid represented by formula (3). Process (2): A step of separating the onium salt represented by formula (1) from the amine-carboxylate produced in step (1) to obtain the onium salt represented by formula (1). [7] The method for purifying an onium salt according to [6], wherein the amine added in the step (1) is an amine represented by the following formula (4): Formula (4): [ka] (In formula (4), R 3 , R 4 and R 5 may be the same or different and are a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms, and the hydrocarbon group may contain a double bond and may contain a branched structure and / or a ring structure. 3 , R 4 and R 5 The total number of carbon atoms in each of these is 8 or more.) [8] The method for purifying an onium salt according to [6], wherein the onium salt represented by the formula (1) is of at least two types. [9] The method for purifying an onium salt according to [6], wherein the mixture containing the onium salt represented by the formula (1) and the carboxylic acid represented by the formula (3) further contains water and / or a hydrophilic solvent.

[10] The method for purifying an onium salt according to [6], wherein the amine added in the step (1) is an amine solution diluted with a solvent. Effect of the Invention

[0014] According to the present invention, a method for producing an onium salt that does not contain carboxylic acid or an onium salt in which the content of carboxylic acid is reduced to such an extent that sufficient solubility of cellulose in the onium salt can be obtained can be provided. Also, according to the present invention, a method for purifying an onium salt can be provided that removes carboxylic acid contained in the onium salt or reduces the content of carboxylic acid to such an extent that sufficient solubility of cellulose in the onium salt can be obtained. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The present invention will be specifically described below. One embodiment of the present invention is The present invention relates to a method for producing an onium salt represented by formula (1), which is characterized by obtaining an onium salt represented by formula (1) from a mixture containing an onium salt represented by formula (1) and a carboxylic acid represented by formula (3), the method including the following steps (1) and (2): Formula (1): [ka] (In formula (1), A + represents pyridinium, ammonium or imidazolium; X - is a carboxylate anion represented by the following formula (2): Formula (2): [ka] In formula (2), R 1 represents a hydrocarbon group having 1 to 12 carbon atoms, which may contain a heteroatom and / or a double bond. Formula (3): [ka] (In formula (3), R 1 is as defined above.) Process (1): A step of adding an amine to a mixture containing the onium salt represented by formula (1) and the carboxylic acid represented by formula (3) to produce an amine-carboxylate consisting of the amine and the carboxylic acid represented by formula (3). Process (2): A step of separating the onium salt represented by formula (1) from the amine-carboxylate produced in step (1) to obtain the onium salt represented by formula (1).

[0016] In the formula (1), A + represents either pyridinium, ammonium or imidazolium.

[0017] The pyridinium includes those represented by the following formula (1-1). Formula (1-1): [ka] (In formula (1-1), R 6 , R 7 , R 8 , R 9 , R 10 and R 11 R may be the same or different and represents a hydrogen atom or a hydrocarbon group which may contain a heteroatom. 6 , R 7 , R 8 , R 9 , R 10 and R 11 may contain a branched or cyclic structure or a double bond, and R 6 , R 7 , R 8 , R 9 , R 10 and R 11 Part or all of R 6 , R 7 , R 8 , R 9 , R 10 and R 11 may be bonded together with the nitrogen atom and carbon atom to which they are bonded to form a ring structure.

[0018] In formula (1-1), R 6 , R 7 , R8 , R 9 , R 10 and R 11 represents a hydrocarbon group which may contain a hydrogen atom or a heteroatom. The "hydrocarbon group which may contain a heteroatom" may be linear, branched, or contain a ring structure or a double bond. 6 , R 7 , R 8 , R 9 , R 10 and R 11 In the above formula, the hydrocarbon group does not necessarily contain a heteroatom.

[0019] In formula (1-1), R 6 , R 7 , R 8 , R 9 , R 10 and R 11 When R is a hydrocarbon group containing no heteroatom, it preferably has 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, and further preferably 1 to 3 carbon atoms. 6 , R 7 , R 8 , R 9 , R 10 and R 11 When is a hydrocarbon group containing a hetero atom, it preferably has 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms, and even more preferably 2 to 4 carbon atoms.

[0020] In formula (1-1), R 6 , R 7 , R 8 , R 9 , R 10 and R 11 When it contains a heteroatom, the number of heteroatoms is preferably 1 to 5, and more preferably 1 to 2. The number of carbon atoms in the hydrocarbon group is 2 or more, preferably 2 to 12, more preferably 2 to 8, and further preferably 2 to 4.

[0021] In formula (1-1), R 6 , R 7 , R 8 , R 9 , R 10 and R 11When is a hydrocarbon group containing a heteroatom, examples of the "heteroatom" include a nitrogen atom, an oxygen atom, a sulfur atom, etc. The number of heteroatoms is preferably 1 to 5, and more preferably 1 to 2.

[0022] In formula (1-1), R 6 , R 7 , R 8 , R 9 , R 10 and R 11 In the above, a "hydrocarbon group containing a heteroatom" refers to a hydrocarbon group not containing a heteroatom, in which (i) the bond between two adjacent carbon atoms and / or (ii) the hydrogen atom of one -CH2- (methylene group) and the hydrogen atom of another -CH2- (methylene group) are bonded together such that -O-, -N<, -NH-, -S-, -C(=O)-O-, -C(=O)-, =N-, -C(=O)-N<, -C(=O)-NH-, -OC(=O)-O-, -OC(=O)-N<, -OC(=O)-NH-, -C(=O) -N[-C(=O)-]-, -C(=O)-NH-C(=O)-, >NC(=O)-N<, >NC(=O)-NH-, -HN-C(=O)-NH-, -S(=O)-, -S(=O)2-, -S(=O)2-O-, -OS(=O)2-O-, >NC(=S)-N<, >NC(=S)-NH-, -HN-C(=S)-NH-, -C(=N-)-, -C(=NH)-, and the like are substituted with structures such as these. The number and combination of substitutions with these structures are not particularly limited. 6 , R 7 , R 8 , R 9 , R 10 and R 11 The number of heteroatoms therein is preferably 1 to 5, and more preferably 1 or 2.

[0023] Preferably, (i) the bond between two adjacent carbon atoms and / or (ii) the hydrogen atom of one -CH2- (methylene group) and the hydrogen atom of the other -CH2- (methylene group) are replaced by an -O- or -S- structure, more preferably by an -O- structure.

[0024] In the present invention, the structure in which (i) the bond between two adjacent carbon atoms and / or (ii) the hydrogen atom of one -CH2- (methylene group) of a hydrocarbon group is replaced with a -O- or -S- structure may be an ether structure, a thioether structure, or an epoxy structure or thioepoxy structure such as an epoxy group, a thioepoxy group, a glycidyl ether group, or an epoxycyclohexyl group. In this case, R 6 , R 7 , R 8 , R 9 , R 10 and R 11 may be an epoxy group, a thioepoxy group, or the like.

[0025] R 6 , R 7 , R 8 , R 9 , R 10 and R 11 When the compound contains two or more -O- and / or -S- structures, the number of carbon atoms between the -O- and / or -S- structures is desirably two or more.

[0026] In formula (1-1), R 6 , R 7 , R 8 , R 9 , R 10 and R 11In the above, examples of the "hydrocarbon group which may contain a heteroatom" include a linear or branched alkyl group which may contain a heteroatom, a linear or branched alkenyl group which may contain a heteroatom, a linear or branched alkynyl group which may contain a heteroatom, a cycloalkyl group which may contain a heteroatom and may be branched, a cycloalkenyl group which may contain a heteroatom and may be branched, an aryl group which may contain a heteroatom and may be branched, an aralkyl group which may contain a heteroatom and may be branched, etc. Preferred are a linear or branched alkyl group which may contain a heteroatom, a linear or branched alkenyl group which may contain a heteroatom, and a cycloalkyl group which may contain a heteroatom and may be branched.

[0027] The "linear or branched alkyl group which may contain a heteroatom" is preferably a linear or branched alkyl group having 1 to 12 carbon atoms which may contain 1 to 5 heteroatoms. In another embodiment, it is preferably a linear or branched alkyl group having 1 to 12 carbon atoms which may contain 1 to 2 heteroatoms, more preferably a linear or branched alkyl group having 1 to 8 carbon atoms which may contain 1 to 2 heteroatoms, and even more preferably a linear or branched alkyl group having 1 to 4 carbon atoms which may contain 1 to 2 heteroatoms. In yet another embodiment, it is preferably a linear or branched alkyl group having 1 to 12 carbon atoms, more preferably a linear or branched alkyl group having 1 to 8 carbon atoms, and even more preferably a linear or branched alkyl group having 1 to 3 carbon atoms.

[0028] The "linear or branched alkenyl group which may contain a heteroatom" is preferably a linear or branched alkenyl group having 2 to 12 carbon atoms which may contain 1 to 5 heteroatoms. In another embodiment, it is preferably a linear or branched alkenyl group having 2 to 12 carbon atoms which may contain 1 to 2 heteroatoms, more preferably a linear or branched alkenyl group having 2 to 8 carbon atoms which may contain 1 to 2 heteroatoms, and even more preferably a linear or branched alkenyl group having 2 to 4 carbon atoms which may contain 1 to 2 heteroatoms. In yet another embodiment, it is preferably a linear or branched alkenyl group having 2 to 12 carbon atoms, more preferably a linear or branched alkenyl group having 2 to 8 carbon atoms, and even more preferably a linear or branched alkenyl group having 2 to 3 carbon atoms.

[0029] The "cycloalkyl group which may contain a heteroatom or may have a branch" is preferably a cycloalkyl group having 3 to 12 carbon atoms which may contain 1 to 5 heteroatoms and which may have a branch. In another embodiment, it is preferably a cycloalkyl group having 3 to 12 carbon atoms which may contain 1 to 2 heteroatoms and which may have a branch, more preferably a cycloalkyl group having 3 to 8 carbon atoms which may contain 1 to 2 heteroatoms and which may have a branch, and even more preferably a cycloalkyl group having 3 to 4 carbon atoms which may contain 1 to 2 heteroatoms. In yet another embodiment, it is preferably a cycloalkyl group having 3 to 12 carbon atoms which may have a branch, more preferably a cycloalkyl group having 3 to 8 carbon atoms which may have a branch, and even more preferably a cycloalkyl group having 3 carbon atoms.

[0030] In formula (1-1), R 6 , R 7 , R 8 , R 9 , R 10 and R 11In the above, specific examples of the "hydrocarbon group not containing a hetero atom" include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, an octyl group, a 2-ethylhexyl group, a decyl group, a dodecyl group, a vinyl group, an ethynyl group, a propenyl group, an isopropenyl group, an allyl group, a propargyl group, a butenyl group, a crotyl group, a butadienyl group, a cyclopropyl group, a cyclobutyl ... Examples of the aryl group include a methyl group, an ethyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, an adamantyl group, a phenyl group, a benzyl group, a tolyl group, a styryl group, and a 2,4,6-trimethylphenyl group. Of these, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a neopentyl group, and a hexyl group are preferred, and a methyl group, an ethyl group, a propyl group, an isopropyl group, and a tert-butyl group are more preferred.

[0031] In formula (1-1), R 6 , R 7 , R 8 , R 9 , R 10 and R 11 In the above, the "hydrocarbon group containing a hetero atom" is preferably a 3-indolyl group, a p-methoxyphenyl group, a 7-oxabicyclo[2,2,1]hept-5-en-2-yl group, a 1,2-epoxyethyl group, a 1-methyl-2-methoxyvinyl group, a 2-furyl group, a 2-pyridyl group, a 4-imidazolyl group, or a benzyloxymethyl group, and more preferably a 1-methyl-2-methoxyvinyl group or a 2-furyl group, although the present invention is not limited thereto.

[0032] In formula (1-1), R 6 , R 7 , R 8 , R 9 , R 10 and R 11 is preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom.

[0033] In formula (1-1), R 6, R 7 , R 8 , R 9 , R 10 and R 11 may be bonded together with the nitrogen atom or carbon atom to which they are attached to form a ring structure. 6 and R 7 , R 7 and R 8 , R 8 and R 9 , R 9 and R 10 , R 10 and R 11 , or R 6 and R 11 Examples of such structures include, but are not limited to, a cyclic structure formed by linking the ring structure with a hydrocarbon having 2 to 24 carbon atoms and containing 2 to 10 heteroatoms.

[0034] Specific examples of the pyridinium represented by formula (1-1) include N-methylpyridinium, N-methyl-2,6-dimethylpyridinium, N-methyl-3,5-dimethylpyridinium, N-methyl-4-methylpyridinium, N-methyl-2,6-methoxymethylpyridinium, N-methyl-2,6-methoxymethoxymethylpyridinium, N-methyl-2,6-methoxyethoxymethylpyridinium, N-methyl-2,6-methoxyethylpyridinium, N-methyl-2,6-methoxymethoxyethylpyridinium, N-methyl-2,6-methoxyethoxyethylpyridinium, and N-ethylpyridinium. N-ethyl-2,6-dimethylpyridinium, N-ethyl-3,5-dimethylpyridinium, N-ethyl-4-methylpyridinium, N-ethyl-2,6-methoxymethylpyridinium, N-ethyl-2,6-methoxymethoxymethylpyridinium, N-ethyl-2,6-methoxyethoxymethylpyridinium, N-ethyl-2,6-methoxyethylpyridinium, N-ethyl-2,6-methoxymethoxyethylpyridinium, N-ethyl-2,6-methoxyethoxyethylpyridinium, N-(2-methoxyethyl)pyridinium, and N-(2-methoxyethyl)pyridinium.

[0035] The ammonium includes ammonium represented by the following formula (1-2). Formula (1-2): [ka] (In formula (1-2), R 12 , R 13 , R 14 and R 15 R may be the same or different and represents a hydrogen atom or a hydrocarbon group which may contain a heteroatom. 12 , R 13 , R 14 and R 15 may contain a branched or cyclic structure or a double bond, and R 12 , R 13 , R 14 and R 15 Part or all of R 12 , R 13 , R 14 and R 15 may be bonded together with the nitrogen atom and carbon atom to which they are bonded to form a ring structure.

[0036] In formula (1-2), R 12 , R 13 , R 14 and R 15 represents a hydrocarbon group which may contain a hydrogen atom or a heteroatom. The "hydrocarbon group which may contain a heteroatom" may be linear, branched, or contain a ring structure or a double bond. 12 , R 13 , R 14 and R 15 In the above formula, the hydrocarbon group does not necessarily contain a heteroatom.

[0037] In formula (1-2), R 12 , R 13 , R 14 and R 15 When R is a hydrocarbon group containing no heteroatom, it preferably has 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, and further preferably 1 to 3 carbon atoms. 12 , R 13 , R 14 and R15 When is a hydrocarbon group containing a hetero atom, it preferably has 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms, and even more preferably 2 to 4 carbon atoms.

[0038] In formula (1-2), R 12 , R 13 , R 14 and R 15 When it contains a heteroatom, the number of heteroatoms is preferably 1 to 5, and more preferably 1 to 2. The number of carbon atoms in the hydrocarbon group is 2 or more, preferably 2 to 12, more preferably 2 to 8, and further preferably 2 to 4.

[0039] In formula (1-2), R 12 , R 13 , R 14 and R 15 When is a hydrocarbon group containing a heteroatom, examples of the "heteroatom" include a nitrogen atom, an oxygen atom, a sulfur atom, etc. The number of heteroatoms is preferably 1 to 5, and more preferably 1 to 2.

[0040] In formula (1-2), R 12 , R 13 , R 14 and R 15In the above, a "hydrocarbon group containing a heteroatom" refers to a hydrocarbon group not containing a heteroatom, in which (i) the bond between two adjacent carbon atoms and / or (ii) the hydrogen atom of one -CH2- (methylene group) and the hydrogen atom of another -CH2- (methylene group) are bonded together such that -O-, -N<, -NH-, -S-, -C(=O)-O-, -C(=O)-, =N-, -C(=O)-N<, -C(=O)-NH-, -OC(=O)-O-, -OC(=O)-N<, -OC(=O)-NH-, -C(=O) -N[-C(=O)-]-, -C(=O)-NH-C(=O)-, >NC(=O)-N<, >NC(=O)-NH-, -HN-C(=O)-NH-, -S(=O)-, -S(=O)2-, -S(=O)2-O-, -OS(=O)2-O-, >NC(=S)-N<, >NC(=S)-NH-, -HN-C(=S)-NH-, -C(=N-)-, -C(=NH)-, and the like are substituted with structures such as these. The number and combination of substitutions with these structures are not particularly limited. 12 , R 13 , R 14 and R 15 The number of heteroatoms therein is preferably 1 to 5, and more preferably 1 or 2.

[0041] Preferably, (i) the bond between two adjacent carbon atoms and / or (ii) the hydrogen atom of one -CH2- (methylene group) and the hydrogen atom of the other -CH2- (methylene group) are replaced by an -O- or -S- structure, more preferably by an -O- structure.

[0042] In the present invention, the structure in which (i) the bond between two adjacent carbon atoms and / or (ii) the hydrogen atom of one -CH2- (methylene group) of a hydrocarbon group is replaced with a -O- or -S- structure may be an ether structure, a thioether structure, or an epoxy structure or thioepoxy structure such as an epoxy group, a thioepoxy group, a glycidyl ether group, or an epoxycyclohexyl group. In this case, R 12 , R 13 , R14 and R 15 may be an epoxy group, a thioepoxy group, or the like.

[0043] R 12 , R 13 , R 14 and R 15 When the compound contains two or more -O- and / or -S- structures, the number of carbon atoms between the -O- and / or -S- structures is desirably two or more.

[0044] In formula (1-2), R 12 , R 13 , R 14 and R 15 In the above, examples of the "hydrocarbon group which may contain a heteroatom" include a linear or branched alkyl group which may contain a heteroatom, a linear or branched alkenyl group which may contain a heteroatom, a linear or branched alkynyl group which may contain a heteroatom, a cycloalkyl group which may contain a heteroatom and may be branched, a cycloalkenyl group which may contain a heteroatom and may be branched, an aryl group which may contain a heteroatom and may be branched, an aralkyl group which may contain a heteroatom and may be branched, etc. Preferred are a linear or branched alkyl group which may contain a heteroatom, a linear or branched alkenyl group which may contain a heteroatom, and a cycloalkyl group which may contain a heteroatom and may be branched.

[0045] The "linear or branched alkyl group which may contain a heteroatom" is preferably a linear or branched alkyl group having 1 to 12 carbon atoms which may contain 1 to 5 heteroatoms. In another embodiment, it is preferably a linear or branched alkyl group having 1 to 12 carbon atoms which may contain 1 to 2 heteroatoms, more preferably a linear or branched alkyl group having 1 to 8 carbon atoms which may contain 1 to 2 heteroatoms, and even more preferably a linear or branched alkyl group having 1 to 4 carbon atoms which may contain 1 to 2 heteroatoms. In yet another embodiment, it is preferably a linear or branched alkyl group having 1 to 12 carbon atoms, more preferably a linear or branched alkyl group having 1 to 8 carbon atoms, and even more preferably a linear or branched alkyl group having 1 to 3 carbon atoms.

[0046] The "linear or branched alkenyl group which may contain a heteroatom" is preferably a linear or branched alkenyl group having 2 to 12 carbon atoms which may contain 1 to 5 heteroatoms. In another embodiment, it is preferably a linear or branched alkenyl group having 2 to 12 carbon atoms which may contain 1 to 2 heteroatoms, more preferably a linear or branched alkenyl group having 2 to 8 carbon atoms which may contain 1 to 2 heteroatoms, and even more preferably a linear or branched alkenyl group having 2 to 4 carbon atoms which may contain 1 to 2 heteroatoms. In yet another embodiment, it is preferably a linear or branched alkenyl group having 2 to 12 carbon atoms, more preferably a linear or branched alkenyl group having 2 to 8 carbon atoms, and even more preferably a linear or branched alkenyl group having 2 to 3 carbon atoms.

[0047] The "cycloalkyl group which may contain a heteroatom or may have a branch" is preferably a cycloalkyl group having 3 to 12 carbon atoms which may contain 1 to 5 heteroatoms and which may have a branch. In another embodiment, it is preferably a cycloalkyl group having 3 to 12 carbon atoms which may contain 1 to 2 heteroatoms and which may have a branch, more preferably a cycloalkyl group having 3 to 8 carbon atoms which may contain 1 to 2 heteroatoms and which may have a branch, and even more preferably a cycloalkyl group having 3 to 4 carbon atoms which may contain 1 to 2 heteroatoms. In yet another embodiment, it is preferably a cycloalkyl group having 3 to 12 carbon atoms which may have a branch, more preferably a cycloalkyl group having 3 to 8 carbon atoms which may have a branch, and even more preferably a cycloalkyl group having 3 carbon atoms.

[0048] In formula (1-2), R 12 , R 13 , R 14 and R 15 In the above, specific examples of the "hydrocarbon group not containing a hetero atom" include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, an octyl group, a 2-ethylhexyl group, a decyl group, a dodecyl group, a vinyl group, an ethynyl group, a propenyl group, an isopropenyl group, an allyl group, a propargyl group, a butenyl group, a crotyl group, a butadienyl group, a cyclopropyl group, a cyclobutyl ... Examples of the aryl group include a methyl group, an ethyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, an adamantyl group, a phenyl group, a benzyl group, a tolyl group, a styryl group, and a 2,4,6-trimethylphenyl group. Of these, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a neopentyl group, and a hexyl group are preferred, and a methyl group, an ethyl group, a propyl group, an isopropyl group, and a tert-butyl group are more preferred.

[0049] In formula (1-2), R 12 , R 13 , R 14 and R 15In the above, the "hydrocarbon group containing a hetero atom" is preferably a 3-indolyl group, a p-methoxyphenyl group, a 7-oxabicyclo[2,2,1]hept-5-en-2-yl group, a 1,2-epoxyethyl group, a 1-methyl-2-methoxyvinyl group, a 2-furyl group, a 2-pyridyl group, a 4-imidazolyl group, or a benzyloxymethyl group, and more preferably a 1-methyl-2-methoxyvinyl group or a 2-furyl group, although the present invention is not limited thereto.

[0050] In formula (1-2), R 12 , R 13 , R 14 and R 15 is preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom.

[0051] In formula (1-2), R 12 , R 13 , R 14 and R 15 may be bonded together with the nitrogen atom or carbon atom to which they are attached to form a ring structure. 12 and R 13 , R 13 and R 14 , R 14 and R 15 , or R 12 and R 15 Examples of such structures include, but are not limited to, a cyclic structure formed by linking the ring structure with a hydrocarbon having 2 to 24 carbon atoms and containing 2 to 10 heteroatoms.

[0052] Specific examples of the ammonium represented by formula (1-2) include tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium, tetrapentylammonium, tetrahexylammonium, tetraheptylammonium, tetraoctylammonium, tetranonylammonium, tetra(decyl)ammonium, N-ethyl-N,N,N-trimethylammonium, N,N,N-trimethyl-N-propylammonium, N-butyl-N,N,N-trimethylammonium, N,N,N-triethyl-N-decylammonium, N,N,N-triethyl-N-eicosylammonium, N,N,N-tributyl-N-pentylammonium, N,N,N-tributyl-N-hexylammonium, N,N,N-tributyl-N-heptylammonium, N,N,N-tributyl-N-octylammonium, N,N,N-tributyl-N-nonylammonium, N,N,N-tributyl-N-decylammonium, N,N,N-tributyl-N-eicosyl Ammonium, N,N-diethyl-N-methyl-N-propylammonium, N-butyl-N,N-diethyl-N-methylammonium, N,N,N-trimethyl-N-(2-methoxyethyl)ammonium, N,N-diethyl-N-(2-methoxyethyl)-N-methylammonium, N,N,N-triethyl-N-(2-ethoxyethyl)ammonium, N,N-diethyl-N-propyl-N-(2-ethoxyethyl)ammonium, N-ethyl-N-[2-(2-methoxyethoxy)ethyl]-N,N -dimethylammonium, N,N-diethyl-N-[2-(2-methoxyethoxy)ethyl]-N-methylammonium, N,N-di(2-methoxyethyl)-N,N-dimethylammonium, N,N-di(2-ethoxyethyl)-N,N-dimethylammonium, N-[2-(2-methoxyethoxy)ethyl]-N-(2-methoxyethyl)-N,N-dimethylammonium, N-(2-ethoxyethyl)-N-[2-(2-methoxyethoxy)ethyl]-N,N-dimethylammonium, and the like.

[0053] The imidazolium includes imidazolium represented by the following formula (1-3): Formula (1-3): [ka] (In formula (1-3), R 16 , R 17 , R 18 , R 19 and R 20 R may be the same or different and represents a hydrogen atom or a hydrocarbon group which may contain a heteroatom. 16 , R 17 , R 18 , R 19 and R 20 may contain a branched or cyclic structure or a double bond, and R 16 , R 17 , R 18 , R 19 and R 20 Part or all of R 16 , R 17 , R 18 , R 19 and R 20 may be bonded together with the nitrogen atom and carbon atom to which they are bonded to form a ring structure.

[0054] In formula (1-3), R 16 , R 17 , R 18 , R 19 and R 20 represents a hydrocarbon group which may contain a hydrogen atom or a heteroatom. The "hydrocarbon group which may contain a heteroatom" may be linear, branched, or contain a ring structure or a double bond. 16 , R 17 , R 18 , R 19 and R 20 In the above formula, the hydrocarbon group does not necessarily contain a heteroatom.

[0055] In formula (1-3), R 16 , R 17 , R 18 , R 19 and R 20 When R is a hydrocarbon group containing no heteroatom, it preferably has 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, and further preferably 1 to 3 carbon atoms. 16, R 17 , R 18 , R 19 and R 20 When is a hydrocarbon group containing a hetero atom, it preferably has 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms, and even more preferably 2 to 4 carbon atoms.

[0056] In formula (1-3), R 16 , R 17 , R 18 , R 19 and R 20 When it contains a heteroatom, the number of heteroatoms is preferably 1 to 5, and more preferably 1 to 2. The number of carbon atoms in the hydrocarbon group is 2 or more, preferably 2 to 12, more preferably 2 to 8, and further preferably 2 to 4.

[0057] In formula (1-3), R 16 , R 17 , R 18 , R 19 and R 20 When is a hydrocarbon group containing a heteroatom, examples of the "heteroatom" include a nitrogen atom, an oxygen atom, a sulfur atom, etc. The number of heteroatoms is preferably 1 to 5, and more preferably 1 to 2.

[0058] In formula (1-3), R 16 , R 17 , R 18 , R 19 and R 20In the above, a "hydrocarbon group containing a heteroatom" refers to a hydrocarbon group not containing a heteroatom, in which (i) the bond between two adjacent carbon atoms and / or (ii) the hydrogen atom of one -CH2- (methylene group) and the hydrogen atom of another -CH2- (methylene group) are bonded together such that -O-, -N<, -NH-, -S-, -C(=O)-O-, -C(=O)-, =N-, -C(=O)-N<, -C(=O)-NH-, -OC(=O)-O-, -OC(=O)-N<, -OC(=O)-NH-, -C(=O) -N[-C(=O)-]-, -C(=O)-NH-C(=O)-, >NC(=O)-N<, >NC(=O)-NH-, -HN-C(=O)-NH-, -S(=O)-, -S(=O)2-, -S(=O)2-O-, -OS(=O)2-O-, >NC(=S)-N<, >NC(=S)-NH-, -HN-C(=S)-NH-, -C(=N-)-, -C(=NH)-, and the like are substituted with structures such as these. The number and combination of substitutions with these structures are not particularly limited. 16 , R 17 , R 18 , R 19 and R 20 The number of heteroatoms therein is preferably 1 to 5, and more preferably 1 or 2.

[0059] Preferably, (i) the bond between two adjacent carbon atoms and / or (ii) the hydrogen atom of one -CH2- (methylene group) and the hydrogen atom of the other -CH2- (methylene group) are replaced by an -O- or -S- structure, more preferably by an -O- structure.

[0060] In the present invention, the structure in which (i) the bond between two adjacent carbon atoms and / or (ii) the hydrogen atom of one -CH2- (methylene group) of a hydrocarbon group is replaced with a -O- or -S- structure may be an ether structure, a thioether structure, or an epoxy structure or thioepoxy structure such as an epoxy group, a thioepoxy group, a glycidyl ether group, or an epoxycyclohexyl group. In this case, R 16 , R17 , R 18 , R 19 and R 20 may be an epoxy group, a thioepoxy group, or the like.

[0061] R 16 , R 17 , R 18 , R 19 and R 20 When the compound contains two or more -O- and / or -S- structures, the number of carbon atoms between the -O- and / or -S- structures is desirably two or more.

[0062] In formula (1-3), R 16 , R 17 , R 18 , R 19 and R 20 In the above, examples of the "hydrocarbon group which may contain a heteroatom" include a linear or branched alkyl group which may contain a heteroatom, a linear or branched alkenyl group which may contain a heteroatom, a linear or branched alkynyl group which may contain a heteroatom, a cycloalkyl group which may contain a heteroatom and may be branched, a cycloalkenyl group which may contain a heteroatom and may be branched, an aryl group which may contain a heteroatom and may be branched, an aralkyl group which may contain a heteroatom and may be branched, etc. Preferred are a linear or branched alkyl group which may contain a heteroatom, a linear or branched alkenyl group which may contain a heteroatom, and a cycloalkyl group which may contain a heteroatom and may be branched.

[0063] The "linear or branched alkyl group which may contain a heteroatom" is preferably a linear or branched alkyl group having 1 to 12 carbon atoms which may contain 1 to 5 heteroatoms. In another embodiment, it is preferably a linear or branched alkyl group having 1 to 12 carbon atoms which may contain 1 to 2 heteroatoms, more preferably a linear or branched alkyl group having 1 to 8 carbon atoms which may contain 1 to 2 heteroatoms, and even more preferably a linear or branched alkyl group having 1 to 4 carbon atoms which may contain 1 to 2 heteroatoms. In yet another embodiment, it is preferably a linear or branched alkyl group having 1 to 12 carbon atoms, more preferably a linear or branched alkyl group having 1 to 8 carbon atoms, and even more preferably a linear or branched alkyl group having 1 to 3 carbon atoms.

[0064] The "linear or branched alkenyl group which may contain a heteroatom" is preferably a linear or branched alkenyl group having 2 to 12 carbon atoms which may contain 1 to 5 heteroatoms. In another embodiment, it is preferably a linear or branched alkenyl group having 2 to 12 carbon atoms which may contain 1 to 2 heteroatoms, more preferably a linear or branched alkenyl group having 2 to 8 carbon atoms which may contain 1 to 2 heteroatoms, and even more preferably a linear or branched alkenyl group having 2 to 4 carbon atoms which may contain 1 to 2 heteroatoms. In yet another embodiment, it is preferably a linear or branched alkenyl group having 2 to 12 carbon atoms, more preferably a linear or branched alkenyl group having 2 to 8 carbon atoms, and even more preferably a linear or branched alkenyl group having 2 to 3 carbon atoms.

[0065] The "cycloalkyl group which may contain a heteroatom or may have a branch" is preferably a cycloalkyl group having 3 to 12 carbon atoms which may contain 1 to 5 heteroatoms and which may have a branch. In another embodiment, it is preferably a cycloalkyl group having 3 to 12 carbon atoms which may contain 1 to 2 heteroatoms and which may have a branch, more preferably a cycloalkyl group having 3 to 8 carbon atoms which may contain 1 to 2 heteroatoms and which may have a branch, and even more preferably a cycloalkyl group having 3 to 4 carbon atoms which may contain 1 to 2 heteroatoms. In yet another embodiment, it is preferably a cycloalkyl group having 3 to 12 carbon atoms which may have a branch, more preferably a cycloalkyl group having 3 to 8 carbon atoms which may have a branch, and even more preferably a cycloalkyl group having 3 carbon atoms.

[0066] In formula (1-3), R 16 , R 17 , R 18 , R 19 and R 20 In the above, specific examples of the "hydrocarbon group not containing a hetero atom" include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, an octyl group, a 2-ethylhexyl group, a decyl group, a dodecyl group, a vinyl group, an ethynyl group, a propenyl group, an isopropenyl group, an allyl group, a propargyl group, a butenyl group, a crotyl group, a butadienyl group, a cyclopropyl group, a cyclobutyl ... Examples of the aryl group include a methyl group, an ethyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, an adamantyl group, a phenyl group, a benzyl group, a tolyl group, a styryl group, and a 2,4,6-trimethylphenyl group. Of these, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a neopentyl group, and a hexyl group are preferred, and a methyl group, an ethyl group, a propyl group, an isopropyl group, and a tert-butyl group are more preferred.

[0067] In formula (1-3), R 16 , R 17 , R 18 , R19 and R 20 In the above, the "hydrocarbon group containing a hetero atom" is preferably a 3-indolyl group, a p-methoxyphenyl group, a 7-oxabicyclo[2,2,1]hept-5-en-2-yl group, a 1,2-epoxyethyl group, a 1-methyl-2-methoxyvinyl group, a 2-furyl group, a 2-pyridyl group, a 4-imidazolyl group, or a benzyloxymethyl group, and more preferably a 1-methyl-2-methoxyvinyl group or a 2-furyl group, although the present invention is not limited thereto.

[0068] In formula (1-3), R 16 , R 17 , R 18 , R 19 and R 20 is preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom.

[0069] In formula (1-3), R 16 , R 17 , R 18 , R 19 and R 20 may be bonded together with the nitrogen atom or carbon atom to which they are attached to form a ring structure. 16 and R 17 , R 17 and R 18 , R 18 and R 19 , R 19 and R 20 , or R 16 and R 20 Examples of such structures include, but are not limited to, a cyclic structure formed by linking the ring structure with a hydrocarbon having 2 to 24 carbon atoms and containing 2 to 10 heteroatoms.

[0070] Specific examples of the imidazolium having a hydrocarbon group containing no heteroatoms and represented by formula (1-3) include 1,3-dimethylimidazolium, 1-ethyl-3-methylimidazolium, 1-methyl-3-propylimidazolium, 1-butyl-3-methylimidazolium, 1-methyl-3-pentylimidazolium, 1-hexyl-3-methylimidazolium, 1-heptyl-3-methylimidazolium, 1-methyl-3-octylimidazolium, 1-methyl-3-nonylimidazolium, 1-decyl-3-methylimidazolium, 1-allyl-3-methylimidazolium, 1-allyl-3-ethylimidazolium, and 1,3-bisallylimidazolium. Preferred are 1-ethyl-3-methylimidazolium and 1-butyl-3-methylimidazolium, but the present invention is not limited thereto.

[0071] Specific examples of the imidazolium having a hydrocarbon group containing a heteroatom and represented by formula (1-3) include 1,3-bis(2-methoxyethyl)imidazolium, 1,3-bis(2-ethoxyethyl)imidazolium, 1,3-bis(2-propoxyethyl)imidazolium, 1,3-bis(2-isopropoxyethyl)imidazolium, 1,3-bis(2-phenoxyethyl)imidazolium, 1,3-bis(2-benzyloxyethyl)imidazolium, 1,3-bis[2-(p-methoxybenzyloxy)ethyl]imidazolium, 1,3-bis[2- (2-methoxyethoxymethoxy)ethyl]imidazolium, 1,3-bis[2-(2-benzyloxyethoxy)ethyl]imidazolium, 1,3-bis(3-methoxypropyl)imidazolium, 1,3-bis(3-ethoxypropyl)imidazolium, 1,3-bis(3-propoxypropyl)imidazolium, 1,3-bis(3-isopropoxypropyl)imidazolium, 1,3-bis(3-allyloxypropyl)imidazolium, 1,3-bis(3-butoxypropyl)imidazolium, 1,3-bis[3-(1-methylpropoxy)propyl]imidazolium, pyryl]imidazolium, 1,3-bis[3-(2-methylpropoxy)propyl]imidazolium, 1,3-bis[3-(1,1-dimethylethoxy)propyl]imidazolium, 1,3-bis[(oxolan-2-yl)methyl]imidazolium, 1,3-bis(3-pentyloxypropyl)imidazolium, 1,3-bis(3-neopentyloxypropyl)imidazolium, 1,3-bis(3-hexyloxypropyl)imidazolium, 1,3-bis(3-cyclohexyloxypropyl)imidazolium, 1,3-bis(3-heptyloxypropyl)imidazolium, propyl)imidazolium, 1,3-bis(3-octyloxypropyl)imidazolium, 1,3-bis(3-nonyloxypropyl)imidazolium, 1,3-bis{3-[(2-ethylhexyl)oxy]propyl}imidazolium, 1,3-bis[3-(2,4,6-trimethylphenoxy)propyl]imidazolium, 1,3-bis[3-(2-methoxyethoxy)propyl]imidazolium, 1,3-bis[2-(dimethylamino)ethyl]imidazolium, 1,3-bis[3-(dimethylamino)propyl]imidazolium, 1,3-Bis(2-methylthioethyl)imidazolium, 1,3-bis{2-[(furan-2-yl)methylthio]ethyl]imidazolium, 1,3-bis[2-(furan-2-yl)methyl]imidazolium, 1,3-bis[1-(methoxymethyl)propyl]imidazolium, 1,3-bis(4-methoxybutyl)imidazolium, 1,3-bis(4-ethoxybutyl)imidazolium, 1,3-bis(4-propoxybutyl)imidazolium, 1,3-bis(4-isopropoxybutyl)imidazolium, 1,3-bis(4-allyloxybutyl)imidazolium )imidazolium, 1,3-bis(4-butoxybutyl)imidazolium, 1,3-bis[4-(1-methylpropoxy)butyl]imidazolium, 1,3-bis[4-(2-methylpropoxy)butyl]imidazolium, 1,3-bis[4-(1,1-dimethylethoxy)butyl]imidazolium, 1,3-bis(4-pentyloxybutyl)imidazolium, 1,3-bis(4-neopentyloxybutyl)imidazolium, 1,3-bis(4-hexyloxybutyl)imidazolium, 1,3-bis(4-cyclohexyloxybutyl)imidazolium imidazolium, 1,3-bis(4-heptyloxybutyl)imidazolium, 1,3-bis(4-octyloxybutyl)imidazolium, 1,3-bis{4-[(2-ethylhexyl)oxy]butyl}imidazolium, 1,3-bis(5-methoxypentyl)imidazolium, 1,3-bis(5-ethoxypentyl)imidazolium, 1,3-bis(5-propoxypentyl)imidazolium, 1,3-bis(5-isopropoxypentyl)imidazolium, 1,3-bis(5-allyloxypentyl)imidazolium, 1,3-bis (5-butoxypentyl)imidazolium, 1,3-bis[5-(1-methylpropoxy)pentyl]imidazolium, 1,3-bis[5-(2-methylpropoxy)pentyl]imidazolium, 1,3-bis[5-(1,1-dimethylethoxy)pentyl]imidazolium, 1,3-bis(5-pentyloxypentyl)imidazolium, 1,3-bis(5-neopentyloxypentyl)imidazolium, 1,3-bis(5-hexyloxypentyl)imidazolium, 1,3-bis(5-cyclohexyloxypentyl)imidazolium, 1,3-Bis(5-heptyloxypentyl)imidazolium, 1,3-bis(6-methoxyhexyl)imidazolium, 1,3-bis(6-ethoxyhexyl)imidazolium, 1,3-bis(6-propoxyhexyl)imidazolium, 1,3-bis(6-isopropoxyhexyl)imidazolium, 1,3-bis(6-allyloxyhexyl)imidazolium, 1,3-bis(6-butoxyhexyl)imidazolium, 1,3-bis[6-(1-methylpropoxy)hexyl]imidazolium, 1,3-bis[6-(2-methylpropoxy)hexyl ]imidazolium, 1,3-bis[6-(1,1-dimethylethoxy)hexyl]imidazolium, 1,3-bis(6-pentyloxyhexyl)imidazolium, 1,3-bis(6-neopentyloxyhexyl)imidazolium, 1,3-bis(6-hexyloxyhexyl)imidazolium, 1,3-bis(6-cyclohexyloxyhexyl)imidazolium, 1,3-bis[(2-methoxycyclohexan-1-yl)methyl]imidazolium, 1,3-bis[(2-ethoxycyclohexan-1-yl)methyl]imidazolium, 1,3- Bis[(2-propoxycyclohexan-1-yl)methyl]imidazolium, 1,3-bis[(2-isopropoxycyclohexan-1-yl)methyl]imidazolium, 1,3-bis[(2-butoxycyclohexan-1-yl)methyl]imidazolium, 1,3-bis{[2-(1-methylpropoxy)cyclohexan-1-yl]methyl}imidazolium, 1,3-bis{[2-(2-methylpropoxy)cyclohexan-1-yl]methyl}imidazolium, 1,3-bis{[2-(1,1-dimethylethoxy)cyclohexan-1-yl] methyl}imidazolium, 1,3-bis[(2-pentyloxycyclohexan-1-yl)methyl]imidazolium, 1,3-bis[(2-neopentyloxycyclohexan-1-yl)methyl]imidazolium, 1,3-bis(3-methylthiopropyl)imidazolium, 1,3-bis[2-(methylsulfonyl)ethyl]imidazolium, 1,3-bis[(thiophen-2-yl)methyl]imidazolium, 1,3-bis(p-methoxyphenyl)imidazolium, 1,3-bis(p-ethoxyphenyl)imidazolium, 1,3-bis(3,4-methylenedioxyphenyl)imidazolium, 1,3-bis(3,4-methylenedioxybenzyl)imidazolium, 1,3-bis{(7-oxabicyclo[2,2,1]heptan-2-yl)methyl}imidazolium, 1-methoxypropyl-3-methylthiopropylimidazolium, 1,3-bis(3-methoxypropyl)-2-methylimidazolium, 1,3-bis(2-methoxyethyl)-2-methylimidazolium, and the like are included, and 1,3-bis(3-methoxypropyl)-2-methylimidazolium is preferable. 1,3-bis(3-ethoxypropyl)imidazolium, 1,3-bis(3-propoxypropyl)imidazolium, 1,3-bis(3-isopropoxypropyl)imidazolium, 1,3-bis(3-allyloxypropyl)imidazolium, 1,3-bis(3-butoxypropyl)imidazolium, 1,3-bis[3-(1-methylpropoxy)propyl]imidazolium, 1,3-bis[3-(2-methylpropoxy)propyl]imidazolium , 1,3-bis[3-(1,1-dimethylethoxy)propyl]imidazolium, 1,3-bis[(oxolan-2-yl)methyl]imidazolium, 1,3-bis[3-(2-methoxyethoxy)propyl]imidazolium, 1,3-bis(3-methylthiopropyl)imidazolium, 1-methoxypropyl-3-methylthiopropylimidazolium, 1,3-bis(3-methoxypropyl)-2-methylimidazolium, 1,3-bis(2-methoxyethyl)-2-methylimidazolium Imidazolium, more preferably 1,3-bis(3-methoxypropyl)imidazolium, 1,3-bis(3-ethoxypropyl)imidazolium, 1-methoxypropyl-3-methylthiopropylimidazolium, 1,3-bis[3-(2-methoxyethoxy)propyl]imidazolium, 1,3-bis(2-methoxyethyl)-2-methylimidazolium, and 1,3-bis(3-methoxypropyl)-2-methylimidazolium, but the present invention is not limited thereto.

[0072] In formula (1), X - is a carboxylate anion represented by the following formula (2). Formula (2): [ka] (In formula (2), R 1 represents a hydrocarbon group having 1 to 12 carbon atoms, which may contain a heteroatom and / or a double bond.

[0073] In formula (2), R 1 represents a hydrocarbon group which may contain a heteroatom. The "hydrocarbon group which may contain a heteroatom" may be linear, branched, or contain a ring structure or a double bond. 1 In the above formula, the hydrocarbon group does not necessarily contain a heteroatom.

[0074] In formula (2), R 1 When R is a hydrocarbon group containing no heteroatom, it preferably has 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, and further preferably 1 to 3 carbon atoms. 1 When is a hydrocarbon group containing a hetero atom, it preferably has 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms, and even more preferably 2 to 4 carbon atoms.

[0075] In formula (2), R 1 When it contains a heteroatom, the number of heteroatoms is preferably 1 to 5, and more preferably 1 to 2. The number of carbon atoms in the hydrocarbon group is 2 or more, preferably 2 to 12, more preferably 2 to 8, and further preferably 2 to 4.

[0076] In formula (2), R 1 When is a hydrocarbon group containing a heteroatom, examples of the "heteroatom" include a nitrogen atom, an oxygen atom, a sulfur atom, etc. The number of heteroatoms is preferably 1 to 5, and more preferably 1 to 2.

[0077] In formula (2), R 1In the above, a "hydrocarbon group containing a heteroatom" refers to a hydrocarbon group not containing a heteroatom, in which (i) the bond between two adjacent carbon atoms and / or (ii) the hydrogen atom of one -CH2- (methylene group) and the hydrogen atom of another -CH2- (methylene group) are bonded together such that -O-, -N<, -NH-, -S-, -C(=O)-O-, -C(=O)-, =N-, -C(=O)-N<, -C(=O)-NH-, -OC(=O)-O-, -OC(=O)-N<, -OC(=O)-NH-, -C(=O) -N[-C(=O)-]-, -C(=O)-NH-C(=O)-, >NC(=O)-N<, >NC(=O)-NH-, -HN-C(=O)-NH-, -S(=O)-, -S(=O)2-, -S(=O)2-O-, -OS(=O)2-O-, >NC(=S)-N<, >NC(=S)-NH-, -HN-C(=S)-NH-, -C(=N-)-, -C(=NH)-, and the like are substituted with structures such as these. The number and combination of substitutions with these structures are not particularly limited. 1 The number of heteroatoms therein is preferably 1 to 5, and more preferably 1 or 2.

[0078] Preferably, (i) the bond between two adjacent carbon atoms and / or (ii) the hydrogen atom of one -CH2- (methylene group) and the hydrogen atom of the other -CH2- (methylene group) are replaced by an -O- or -S- structure, more preferably by an -O- structure.

[0079] In the present invention, the structure in which (i) the bond between two adjacent carbon atoms and / or (ii) the hydrogen atom of one -CH2- (methylene group) of a hydrocarbon group is replaced with a -O- or -S- structure may be an ether structure, a thioether structure, or an epoxy structure or thioepoxy structure such as an epoxy group, a thioepoxy group, a glycidyl ether group, or an epoxycyclohexyl group. In this case, R 1 may be an epoxy group, a thioepoxy group, or the like.

[0080] R1 When the compound contains two or more -O- and / or -S- structures, the number of carbon atoms between the -O- and / or -S- structures is desirably two or more.

[0081] In formula (2), R 1 In the above, examples of the "hydrocarbon group which may contain a heteroatom" include a linear or branched alkyl group which may contain a heteroatom, a linear or branched alkenyl group which may contain a heteroatom, a linear or branched alkynyl group which may contain a heteroatom, a cycloalkyl group which may contain a heteroatom and may be branched, a cycloalkenyl group which may contain a heteroatom and may be branched, an aryl group which may contain a heteroatom and may be branched, an aralkyl group which may contain a heteroatom and may be branched, etc. Preferred are a linear or branched alkyl group which may contain a heteroatom, a linear or branched alkenyl group which may contain a heteroatom, and a cycloalkyl group which may contain a heteroatom and may be branched.

[0082] The "linear or branched alkyl group which may contain a heteroatom" is preferably a linear or branched alkyl group having 1 to 12 carbon atoms which may contain 1 to 5 heteroatoms. In another embodiment, it is preferably a linear or branched alkyl group having 1 to 12 carbon atoms which may contain 1 to 2 heteroatoms, more preferably a linear or branched alkyl group having 1 to 8 carbon atoms which may contain 1 to 2 heteroatoms, and even more preferably a linear or branched alkyl group having 1 to 4 carbon atoms which may contain 1 to 2 heteroatoms. In yet another embodiment, it is preferably a linear or branched alkyl group having 1 to 12 carbon atoms, more preferably a linear or branched alkyl group having 1 to 8 carbon atoms, and even more preferably a linear or branched alkyl group having 1 to 3 carbon atoms.

[0083] The "linear or branched alkenyl group which may contain a heteroatom" is preferably a linear or branched alkenyl group having 2 to 12 carbon atoms which may contain 1 to 5 heteroatoms. In another embodiment, it is preferably a linear or branched alkenyl group having 2 to 12 carbon atoms which may contain 1 to 2 heteroatoms, more preferably a linear or branched alkenyl group having 2 to 8 carbon atoms which may contain 1 to 2 heteroatoms, and even more preferably a linear or branched alkenyl group having 2 to 4 carbon atoms which may contain 1 to 2 heteroatoms. In yet another embodiment, it is preferably a linear or branched alkenyl group having 2 to 12 carbon atoms, more preferably a linear or branched alkenyl group having 2 to 8 carbon atoms, and even more preferably a linear or branched alkenyl group having 2 to 3 carbon atoms.

[0084] The "cycloalkyl group which may contain a heteroatom or may have a branch" is preferably a cycloalkyl group having 3 to 12 carbon atoms which may contain 1 to 5 heteroatoms and which may have a branch. In another embodiment, it is preferably a cycloalkyl group having 3 to 12 carbon atoms which may contain 1 to 2 heteroatoms and which may have a branch, more preferably a cycloalkyl group having 3 to 8 carbon atoms which may contain 1 to 2 heteroatoms and which may have a branch, and even more preferably a cycloalkyl group having 3 to 4 carbon atoms which may contain 1 to 2 heteroatoms. In yet another embodiment, it is preferably a cycloalkyl group having 3 to 12 carbon atoms which may have a branch, more preferably a cycloalkyl group having 3 to 8 carbon atoms which may have a branch, and even more preferably a cycloalkyl group having 3 carbon atoms.

[0085] In formula (2), R 1In the above, specific examples of the "hydrocarbon group not containing a hetero atom" include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, an octyl group, a 2-ethylhexyl group, a decyl group, a dodecyl group, a vinyl group, an ethynyl group, a propenyl group, an isopropenyl group, an allyl group, a propargyl group, a butenyl group, a crotyl group, a butadienyl group, a cyclopropyl group, a cyclobutyl ... Examples of the aryl group include a methyl group, an ethyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, an adamantyl group, a phenyl group, a benzyl group, a tolyl group, a styryl group, and a 2,4,6-trimethylphenyl group. Of these, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a neopentyl group, and a hexyl group are preferred, and a methyl group, an ethyl group, a propyl group, an isopropyl group, and a tert-butyl group are more preferred.

[0086] In formula (2), R 1 In the above, the "hydrocarbon group containing a hetero atom" is preferably a 3-indolyl group, a p-methoxyphenyl group, a 7-oxabicyclo[2,2,1]hept-5-en-2-yl group, a 1,2-epoxyethyl group, a 1-methyl-2-methoxyvinyl group, a 2-furyl group, a 2-pyridyl group, a 4-imidazolyl group, or a benzyloxymethyl group, and more preferably a 1-methyl-2-methoxyvinyl group or a 2-furyl group, although the present invention is not limited thereto.

[0087] In formula (2), R 1 is preferably a methyl group, an ethyl group, a methoxymethyl group, or a methoxyethyl group.

[0088] Specific examples of the carboxylate anion represented by formula (2) include acetate ion, propionate ion, acrylate ion, propargyl ion, butyrate ion, isobutyrate ion, methacrylate ion, crotonate ion, tetrolate ion, cyclopropanecarboxylate ion, valerate ion, isovalerate ion, pivalate ion, angelic acid ion, tiglate ion, cyclobutanecarboxylate ion, caproate ion, cyclopentanecarboxylate ion, enanthate ion, sorbic acid ion, cyclohexanecarboxylate ion, benzoate ion, caprylate ion, 2-ethylhexylcarboxylate ion, toluate ion, 2-norbornanecarboxylate ion, pelargonate ion, cinnamate ion, capric acid ion, adamantanecarboxylate ion, geranate ion, undecylate ion, lauric acid ion, and naphthalenecarboxylate ion. Of these, acetate ion, propionate ion, acrylate ion, propargyl ion, butyrate ion, and isovalerate ion are preferred. Butyrate, methacrylate, crotonate, tetrolate, valerate, isovalerate, pivalate, methoxyacetate, ethoxyacetate, propoxyacetate, (2-methoxyethoxy)acetate, (2-ethoxyethoxy)acetate, (2-propoxyethoxy)acetate, 3-(2-methoxyethoxy)propanoate, 3-(2-ethoxyethoxy)propanoate, 3-(2-propoxyethoxy)propanoate, 3-(3-methoxy ... 3-(3-ethoxypropoxy)propanoate ion, 3-(3-propoxypropoxy)propanoate ion, 3-[2-(2-methoxyethoxy)ethoxy]propanoate ion, 3-[2-(2-ethoxyethoxy)ethoxy]propanoate ion, 4,7,10,13-tetraoxatetradecanoate ion, 4,7,10,13-tetraoxapentadecanoate ion, 4,7,10,13,16-pentaoxaheptadecanoate ion, 4,7,10,Examples of the 13,16-pentaoxaoctadecanoic acid ion include a (methylthio)acetate ion, a (ethylthio)acetate ion, a 3-(methylthio)propanoic acid ion, a 3-[(2-methoxyethyl)thio]propanoic acid ion, and a 3-[(2-ethoxyethyl)thio]propanoic acid ion. Of these, preferred are a methoxyacetate ion, a 3-(2-methoxyethoxy)propanoic acid ion, a 3-(2-ethoxyethoxy)propanoic acid ion, and a 3-[2-(2-methoxyethoxy)ethoxy]propanoic acid ion. ion, 3-[2-(2-ethoxyethoxy)ethoxy]propanoate ion, 4,7,10,13-tetraoxatetradecanoate ion, particularly preferably methoxyacetate ion, 3-(2-methoxyethoxy)propanoate ion, 3-(2-ethoxyethoxy)propanoate ion, 3-(methylthio)propanoate ion, particularly preferably acetate ion, methoxyacetate ion, acrylate ion, or methacrylate ion, although the present invention is not limited thereto.

[0089] The carboxylic acid used in the present invention is a carboxylic acid represented by the formula (3). Formula (3): [ka] (In formula (3), R 1 is as defined above.)

[0090] R in Equation (3) 1 is R in Eq. (2). 1 is the same as:

[0091] Specific examples of the carboxylic acid represented by formula (3) include acetic acid, propionic acid, acrylic acid, propargylic acid, butyric acid, isobutyric acid, methacrylic acid, crotonic acid, tetrolic acid, cyclopropanecarboxylic acid, valeric acid, isovaleric acid, pivalic acid, angelic acid, tiglic acid, cyclobutanecarboxylic acid, caproic acid, cyclopentanecarboxylic acid, enanthic acid, sorbic acid, cyclohexanecarboxylic acid, benzoic acid, caprylic acid, 2-ethylhexylcarboxylic acid, toluic acid, 2-norbornanecarboxylic acid, pelargonic acid, Examples of the carboxylic acids include cinnamic acid, capric acid, adamantanecarboxylic acid, geranic acid, undecylic acid, lauric acid, and naphthalenecarboxylic acid. Of these, preferred are acetic acid, propionic acid, acrylic acid, propargylic acid, butyric acid, isobutyric acid, methacrylic acid, crotonic acid, tetrolic acid, valeric acid, isovaleric acid, pivalic acid, methoxyacetic acid, ethoxyacetic acid, propoxyacetic acid, (2-methoxyethoxy)acetic acid, (2-ethoxyethoxy)acetic acid, (2-propoxyethoxy)acetic acid, 3-(2-methoxyethoxy)propanoic acid, 3-(2-ethoxyethoxy)propanoic acid, and 3-(2-ethoxyethoxy)propanoic acid. 2-(2-propoxyethoxy)propanoic acid, 3-(3-methoxypropoxy)propanoic acid, 3-(3-ethoxypropoxy)propanoic acid, 3-(3-propoxypropoxy)propanoic acid, 3-[2-(2-methoxyethoxy)ethoxy]propanoic acid, 3-[2-(2-ethoxyethoxy)ethoxy]propanoic acid, 4,7,10,13-tetraoxatetradecanoic acid, 4,7,10,13-tetraoxapentadecanoic acid, 4,7,10,13,16-pentaoxaheptadecanoic acid, 4, 7,10,13,16-pentaoxaoctadecanoic acid, (methylthio)acetic acid, (ethylthio)acetic acid, 3-(methylthio)propanoic acid, 3-[(2-methoxyethyl)thio]propanoic acid, 3-[(2-ethoxyethyl)thio]propanoic acid, and the like are included, and preferred are methoxyacetic acid, 3-(2-methoxyethoxy)propanoic acid, 3-(2-ethoxyethoxy)propanoic acid, 3-[2-(2-methoxyethoxy)ethoxy]propanoic acid, 3-[2-(2-ethoxyethoxy)ethoxy]propanoic acid, 4,7,10,13-tetraoxatetradecanoic acid, particularly preferably methoxyacetic acid, 3-(2-methoxyethoxy)propanoic acid, 3-(2-ethoxyethoxy)propanoic acid, 3-(methylthio)propanoic acid, particularly preferably acetic acid, methoxyacetic acid, acrylic acid, or methacrylic acid, although the present invention is not limited thereto.

[0092] The pyridinium salt represented by formula (1) is preferably N-methylpyridinium, N-methyl-2,6-dimethylpyridinium, N-methyl-3,5-dimethylpyridinium, N-methyl-4-methylpyridinium, N-methyl-2,6-methoxymethylpyridinium, N-methyl-2,6-methoxymethoxymethylpyridinium, N-methyl-2,6-methoxyethoxymethylpyridinium, N-methyl-2,6-methoxyethylpyridinium, N-methyl-2,6-methoxymethoxyethylpyridinium, N-methyl-2,6-methoxyethoxyethylpyridinium, N-ethylpyridinium, N-ethyl-2,6-dimethylpyridinium, N-ethyl-3,5-dimethylpyridinium, N- The pyridinium salt is a combination of one cation selected from the group consisting of ethyl-4-methylpyridinium, N-ethyl-2,6-methoxymethylpyridinium, N-ethyl-2,6-methoxymethoxymethylpyridinium, N-ethyl-2,6-methoxyethoxymethylpyridinium, N-ethyl-2,6-methoxyethylpyridinium, N-ethyl-2,6-methoxymethoxyethylpyridinium, N-ethyl-2,6-methoxyethoxyethylpyridinium, N-(2-methoxyethyl)pyridinium, and N-(2-methoxyethyl)pyridinium, and one anion selected from the group consisting of acetate ion, methoxyacetate ion, acrylate ion, and methacrylate ion.

[0093] More specifically, the pyridinium salt represented by formula (1) includes N-methylpyridinium acetate, N-methyl-2,6-dimethylpyridinium acetate, N-methyl-3,5-dimethylpyridinium acetate, N-methyl-4-methylpyridinium acetate, N-(2-methoxyethyl)pyridinium, N-(2-methoxyethyl)pyridinium, and the like. Of these, N-(2-methoxyethyl)pyridinium acetate and N-(2-methoxyethyl)pyridinium acetate are preferred, but the present invention is not limited thereto.

[0094] Preferred examples of the ammonium salt represented by formula (1) include tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium, tetrapentylammonium, tetrahexylammonium, tetraheptylammonium, tetraoctylammonium, tetranonylammonium, tetra(decyl)ammonium, N-ethyl-N,N,N-trimethylammonium, N,N,N-trimethyl-N-propylammonium, N-butyl-N,N,N-trimethylammonium, and N,N,N-triethyl-N-decylammonium. N,N,N-triethyl-N-eicosylammonium, N,N,N-tributyl-N-pentylammonium, N,N,N-tributyl-N-hexylammonium, N,N,N-tributyl-N-heptylammonium, N,N,N-tributyl-N-octylammonium, N,N,N-tributyl-N-nonylammonium, N,N,N-tributyl-N-decylammonium, N,N,N-tributyl-N-eicosylammonium, N,N-diethyl-N-methyl-N-propylammonium, N-butyl-N,N-diethyl N-propyl-N-methylammonium, N,N,N-trimethyl-N-(2-methoxyethyl)ammonium, N,N-diethyl-N-(2-methoxyethyl)-N-methylammonium, N,N,N-triethyl-N-(2-ethoxyethyl)ammonium, N,N-diethyl-N-propyl-N-(2-ethoxyethyl)ammonium, N-ethyl-N-[2-(2-methoxyethoxy)ethyl]-N,N-dimethylammonium, N,N-diethyl-N-[2-(2-methoxyethoxy)ethyl]-N-methylammonium, N,N-di(2-methoxyethyl) )-N,N-dimethylammonium, N,N-di(2-ethoxyethyl)-N,N-dimethylammonium, N-[2-(2-methoxyethoxy)ethyl]-N-(2-methoxyethyl)-N,N-dimethylammonium, and N-(2-ethoxyethyl)-N-[2-(2-methoxyethoxy)ethyl]-N,N-dimethylammonium, and a combination of one cation selected from the group consisting of acetate ion, methoxyacetate ion, acrylate ion, and methacrylate ion.

[0095] More specifically, the ammonium salt represented by formula (1) includes N,N-diethyl-N-(2-methoxyethyl)-N-methylammonium and N-ethyl-N-[2-(2-methoxyethoxy)ethyl]-N,N-dimethylammonium, and preferably N-ethyl-N-[2-(2-methoxyethoxy)ethyl]-N,N-dimethylammonium methoxyacetate, but the present invention is not limited thereto.

[0096] The imidazolium salt represented by formula (1) is preferably an onium salt composed of a combination of one cation selected from the group consisting of 1,3-bis(2-methoxyethyl)imidazolium, 1,3-bis(3-methoxypropyl)imidazolium, 1,3-bis(3-ethoxypropyl)imidazolium, 1,3-bis(3-methylthiopropyl)imidazolium, 1,3-bis[3-(2-methoxyethoxy)propyl]imidazolium, 1-methoxypropyl-3-methylthiopropylimidazolium, 1,3-bis(2-methoxyethyl)-2-methylimidazolium, and 1,3-bis(3-methoxypropyl)-2-methylimidazolium, and one anion selected from the group consisting of acetate ion, methoxyacetate ion, acrylate ion, and methacrylate ion.

[0097] More specifically, the onium salt represented by formula (1) includes 1,3-bis(2-methoxyethyl)imidazolium acetate, 1,3-bis(3-methoxypropyl)imidazolium acetate, 1,3-bis(3-methoxypropyl)imidazolium acrylate, 1,3-bis(3-methoxypropyl)imidazolium methacrylate, 1,3-bis(3-ethoxypropyl)imidazolium acetate, 1-methoxypropyl-3-methylthiopropylimidazolium acetate, 1,3-bis(3-methylthiopropyl)imidazolium acetate, 1,3-bis(2-methoxyethyl)-2-methylimidazolium acetate, 1,3-bis(2-methoxyethyl)-2-methylimidazolium acrylate, 1,3-bis(2-methoxyethyl)-2-methylimidazolium methacrylate, 1, Examples of the imidazolium methacrylate include 3-bis(3-methoxypropyl)-2-methylimidazolium acetate, 1,3-bis(3-methoxypropyl)-2-methylimidazolium acrylate, 1,3-bis(3-methoxypropyl)-2-methylimidazolium methacrylate, 1,3-bis[3-(2-methoxyethoxy)propyl]imidazolium acetate, 1,3-bis[3-(2-methoxyethoxy)propyl]imidazolium acrylate, and 1,3-bis[3-(2-methoxyethoxy)propyl]imidazolium methacrylate. Preferred are 1,3-bis(3-methoxypropyl)imidazolium acetate, 1,3-bis(3-methoxypropyl)imidazolium acrylate, and 1,3-bis(3-methoxypropyl)imidazolium methacrylate, but the present invention is not limited thereto.

[0098] For example, when an onium salt is produced by the following reaction formula (1), a mixture containing the onium salt and the carboxylic acid is obtained, and in the following reaction formula, the carboxylic acid remains. The production of an onium salt will be described using the following reaction formula (1). In the reaction formula (1), A + represents any one of pyridinium, ammonium, or imidazolium as defined above, and Y - is a halogen ion, OH- is a hydroxyl ion, R 1 is as defined above, R 1 -C(=O)OH is a carboxylic acid, R 1 -C(=O)O - is a carboxylate anion.

[0099] Reaction Scheme 1: [ka]

[0100] The onium salt represented by formula (1) of the present invention is usually + Y - An onium halide salt represented by the formula (I) can be converted into an onium hydroxide salt by ion exchange (called the first ion exchange) using an ion exchange resin, silver oxide, an alkali metal salt, or the like, and then an onium carboxylate salt can be converted into an onium carboxylate salt by ion exchange (called the second ion exchange) between the hydroxide ion of the obtained hydroxide salt and the carboxylate anion of the carboxylic acid.

[0101] The onium halide salt used in the above reaction formula is the above-mentioned A + Pyridinium, ammonium or imidazolium having Y - Examples of the halogen ions include compounds in which a halogen ion such as a chlorine ion, a bromine ion, or an iodine ion is combined, as represented by the following formula:

[0102] The ion exchange resin used in the first ion exchange may be, for example, a strongly basic ion exchange resin commercially available for water treatment or catalyst use. The amount of the ion exchange resin used is usually 20 equivalents or less, preferably 1 to 10 equivalents, and particularly preferably 2 to 5 equivalents, relative to 1 equivalent of the halide salt.

[0103] The amount of silver oxide used in the first ion exchange is usually 10 equivalents or less, preferably 0.5 to 2 equivalents, and particularly preferably 0.5 to 0.7 equivalents, relative to 1 equivalent of the halide salt.

[0104] Examples of the alkali metal salt used in the first ion exchange include sodium hydroxide, potassium hydroxide, etc. The amount of the alkali metal salt used is usually 3 equivalents or less relative to 1 equivalent of the halide salt.

[0105] The first ion exchange is usually carried out in a solvent. Examples of the solvent include alcohols such as acetone, methanol, ethanol, and 2-propanol, acetonitrile, ethyl acetate, and water. The amount of the solvent used is not particularly limited, but is usually 10 parts by weight or less, preferably 1 to 10 parts by weight, and particularly preferably 2 to 6 parts by weight, relative to 1 part by weight of the halide salt.

[0106] The reaction temperature of the first ion exchange is usually 10°C or higher, preferably 10 to 60°C, and particularly preferably 10 to 30°C.

[0107] The reaction mixture obtained in the first ion exchange is usually used as it is in the second ion exchange with hydroxide ions and carboxylate anions, or after removing insoluble matter by filtration, it is used in the second ion exchange.

[0108] The hydroxy salt obtained by the first ion exchange is the above-mentioned A + Pyridinium, ammonium or imidazolium is OH - Examples of the compound include a combination of the above.

[0109] Next, the second ion exchange will be described. The amount of the carboxylic acid used in the second ion exchange is usually 1 equivalent or more, preferably 1 to 2 equivalents, and particularly preferably 1.1 to 1.5 equivalents, relative to 1 equivalent of the hydroxide salt.

[0110] The second ion exchange is usually carried out in a solvent. Examples of the solvent include ketones such as acetone and methyl ethyl ketone, alcohols such as methanol, ethanol and 2-propanol, acetonitrile, ethyl acetate, tetrahydrofuran, dimethylformaldehyde, water, etc. The amount of the solvent used is not particularly limited, but is usually 10 parts by weight or less, preferably 1 to 10 parts by weight, and particularly preferably 1 to 6 parts by weight, relative to 1 part by weight of the hydroxide salt.

[0111] The reaction temperature of the second ion exchange is usually 10°C or higher, preferably 10 to 60°C, and particularly preferably 10 to 30°C.

[0112] By the second ion exchange, a mixture containing the onium salt and the carboxylic acid used in the second ion exchange is obtained, and the carboxylic acid remains in the mixture. The reaction mixture obtained by the second ion exchange can be concentrated by heating and / or reducing pressure to distill off the carboxylic acid used in the second ion exchange, but some carboxylic acid cannot be distilled off and remains in the mixture. Furthermore, in cases where the onium salt obtained by the second ion exchange is one that crystallizes, it can be purified by recrystallization, but the carboxylic acid may remain in the crystals of the onium salt obtained.

[0113] Furthermore, when an ammonium salt is produced by the method described in Patent Document 3, for example, a mixture of the ammonium salt represented by formula (1) and a carboxylic acid is obtained, and the carboxylic acid remains.

[0114] The following describes a method for producing an ammonium salt described in Patent Document 3. The method for producing an ammonium salt described in Patent Document 3 is a method in which a quaternary ammonium alkyl carbonate is first produced from a dialkyl carbonate and a tertiary amine, and then a quaternary ammonium carboxylate is produced from the quaternary ammonium alkyl carbonate.

[0115] A method for producing a quaternary ammonium alkyl carbonate from a dialkyl carbonate and a tertiary amine is described. Specific examples of the dialkyl carbonate include dimethyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl carbonate, dipentyl carbonate, dihexyl carbonate, and the like, and preferred are dimethyl carbonate and diethyl carbonate.

[0116] Specific examples of tertiary amines include trimethylamine, triethylamine, N,N-dimethyl-N-(methoxymethyl)amine, N-(2-methoxyethyl)-N,N-dimethylamine, N,N-diethyl-N-(methoxymethyl)amine, and N,N-diethyl-N-(2-methoxyethyl)amine, with N,N-diethyl-N-(2-methoxyethyl)amine being preferred.

[0117] Specific examples of quaternary ammonium alkyl carbonates include tetramethylammonium methyl carbonate, triethylmethylammonium methyl carbonate, N,N,N-trimethyl-N-(methoxymethyl)ammonium methyl carbonate, N-(2-methoxyethyl)-N,N,N-trimethylammonium methyl carbonate, N,N-diethyl-N-(methoxymethyl)-N-methylammonium methyl carbonate, N,N-diethyl-N-(2-methoxyethyl)-N-methylammonium methyl carbonate, and the like, with N,N-diethyl-N-(2-methoxyethyl)-N-methylammonium methyl carbonate being preferred.

[0118] The amount of dialkyl carbonate used is usually 0.5 equivalents or more, and preferably 1.0 to 6.0 equivalents, relative to 1 equivalent of the tertiary amine.

[0119] In the reaction for producing a quaternary ammonium alkyl carbonate, a solvent may or may not be used. When a solvent is used, the solvent is not particularly limited as long as it does not affect the reaction. Specific examples of the solvent include methanol, ethanol, propanol, butanol, pentanol, hexanol, etc., and preferably methanol and ethanol. The amount of the solvent used is usually 50 parts by weight or less, preferably 10 parts by weight or less, per part by weight of the tertiary amine.

[0120] The optimum reaction temperature for the reaction for producing a quaternary ammonium alkyl carbonate varies depending on the raw materials, solvent, etc. used, but is usually room temperature or higher, and preferably 20 to 200°C.

[0121] The reaction pressure in the reaction for producing the quaternary ammonium alkyl carbonate is usually 1 MPa or more, preferably 1 to 5 MPa, and more preferably 1 to 2 MPa, from the viewpoint of not leaving a large amount of by-products in the quaternary ammonium alkyl carbonate.

[0122] In the reaction for producing a quaternary ammonium alkyl carbonate, the reaction may be carried out, if necessary, in an atmosphere of an inert gas that does not affect the reaction, such as nitrogen, argon, or helium.

[0123] In the reaction for producing a quaternary ammonium alkyl carbonate, after the reaction is completed, the reaction solution can be concentrated to distill off the solvent, dialkyl carbonate, tertiary amine, etc., to isolate the quaternary ammonium alkyl carbonate. Alternatively, the reaction solution can be used as it is for producing a quaternary ammonium carboxylate without isolating the quaternary ammonium alkyl carbonate.

[0124] A method for producing a quaternary ammonium carboxylate from a quaternary ammonium alkyl carbonate is described. Quaternary ammonium carboxylates are produced by reacting a quaternary ammonium alkyl carbonate with a carboxylic acid to effect anion exchange between the alkyl carbonate anion of the quaternary ammonium alkyl carbonate and the carboxylate anion of the carboxylic acid. Specific examples of carboxylic acids include acetic acid, methoxyacetic acid, ethoxyacetic acid, propionic acid, 3-(2-methoxyethoxy)propionic acid, 3-(2-ethoxyethoxy)propionic acid, and the like, and preferred are acetic acid, methoxyacetic acid, propionic acid, and 3-(2-methoxyethoxy)propionic acid.

[0125] Specific examples of the quaternary ammonium carboxylate include tetramethylammonium acetate, tetramethylammonium propionate, tetramethylammonium methoxyacetate, triethylmethylammonium acetate, triethylmethylammonium propionate, triethylmethylammonium methoxyacetate, N,N-diethyl-N-(methoxymethyl)-N-methylammonium acetate, N,N-diethyl-N-(methoxymethyl)-N-methylammonium propionate, N,N-diethyl-N-(methoxymethyl)-N-methylammonium methoxyacetate, N,N-diethyl-N-(2-methoxyethyl)-N-methylammonium acetate, N,N-diethyl-N-(2-methoxyethyl)-N-methylammonium propionate, and N,N-diethyl-N-(2-methoxyethyl)-N-methylammonium methoxyacetate. Of these, N,N-diethyl-N-(2-methoxyethyl)-N-methylammonium acetate is preferred.

[0126] In the anion exchange reaction between a quaternary ammonium alkyl carbonate and a carboxylic acid, a solvent may or may not be used. When a solvent is used, the solvent is not particularly limited as long as it does not affect the reaction. Specific examples of the solvent include methanol, ethanol, propanol, butanol, acetonitrile, etc., and preferably methanol and ethanol. These may be used in combination of two or more. The amount of the solvent used is usually 50 parts by weight or less, preferably 10 parts by weight or less, per part by weight of the quaternary ammonium alkyl carbonate.

[0127] The reaction temperature for the anion exchange reaction between the quaternary ammonium alkyl carbonate and the carboxylic acid is not particularly limited, but is usually 10°C or higher, preferably 10 to 60°C, and particularly preferably 10 to 40°C.

[0128] By the anion exchange reaction between the quaternary ammonium alkyl carbonate and the carboxylic acid, a mixture containing the quaternary ammonium carboxylate and the carboxylic acid used in the anion exchange is obtained, and the carboxylic acid remains in the mixture. The reaction mixture obtained by the anion exchange can be concentrated by heating and / or reducing pressure to distill off the carboxylic acid used in the anion exchange, but some of the carboxylic acid cannot be distilled off and remains in the mixture. In addition, if the resulting quaternary ammonium carboxylate is crystallized by anion exchange, it can be purified by recrystallization, but the carboxylic acid may remain in the resulting quaternary ammonium carboxylate crystals.

[0129] The present invention is a method for obtaining an onium salt represented by formula (1) from a mixture containing an onium salt represented by formula (1) and a carboxylic acid represented by formula (3), the method comprising the following steps (1) and (2). Process (1): A step of adding an amine to a mixture containing the onium salt represented by formula (1) and the carboxylic acid represented by formula (3) to produce an amine-carboxylate consisting of the amine and the carboxylic acid represented by formula (3). Process (2): A step of separating the onium salt represented by formula (1) from the amine-carboxylate produced in step (1) to obtain the onium salt represented by formula (1).

[0130] The mixture containing the onium salt represented by formula (1) and the carboxylic acid represented by formula (3) used in step (1) is obtained by producing the onium salt represented by formula (1) using the carboxylic acid represented by formula (3), and is a mixture in which the carboxylic acid represented by formula (3) remains in the onium salt represented by formula (1). The amount of the remaining carboxylic acid of formula (3) is usually 1.5 equivalents or less per equivalent of the onium salt of formula (1).

[0131] The amine added in step (1) is preferably an amine represented by the following formula (4). Formula (4): [ka] (In formula (4), R 3 , R 4 and R 5 may be the same or different and are a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms, and the hydrocarbon group may contain a double bond and may contain a branched structure and / or a ring structure. 3 , R 4 and R 5 The total number of carbon atoms in each of these is 8 or more.)

[0132] In formula (4), R 3 , R 4 and R 5 In the above formula, the hydrocarbon group has 1 to 18 carbon atoms, more preferably 1 to 12 carbon atoms, and further preferably 1 to 8 carbon atoms. R 3 , R 4 and R 5 The total number of carbon atoms contained in each of these is 8 or more, and preferably 12 or more and 24 or less.

[0133] R 3 , R 4 and R 5 In the above, specific examples of the hydrocarbon group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, an octyl group, a 2-ethylhexyl group, a decyl group, a dodecyl group, an octadecyl group, etc. In addition, the isopropyl group, the sec-butyl group, the isobutyl group, the tert-butyl group, the neopentyl group, and the 2-ethylhexyl group each include a branched structure.

[0134] R 3 , R 4 and R 5 Specific examples of the hydrocarbon group containing a double bond in the above formula include a vinyl group, an ethynyl group, a propenyl group, an isopropenyl group, an allyl group, a propargyl group, a butenyl group, a crotyl group, a butadienyl group, and an oleyl group.

[0135] R 3 , R 4 and R 5 In the above, specific examples of the hydrocarbon group containing a ring structure include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, an adamantyl group, a phenyl group, a benzyl group, a tolyl group, a styryl group, and a 2,4,6-trimethylphenyl group. In addition, the cyclopropyl group, the cyclobutyl group, the cyclopentyl group, the cyclohexyl group, the norbornyl group, and the adamantyl group each contain a branched structure.

[0136] R 3 , R 4 and R 5 is preferably a hydrogen atom, a methyl group, an oleyl group, a 2-ethylhexyl group, a cyclohexyl group, an octadecyl group, or an octyl group.

[0137] Specific examples of the amine represented by formula (4) include tripropylamine, tributylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, oleylamine, di-2-ethylhexylamine, dicyclohexylamine, methyloctadecylamine, dimethyloctadecylamine, and trioctylamine.

[0138] The amount of amine added to the mixture containing the onium salt represented by formula (1) and the carboxylic acid represented by formula (3) is 1 equivalent or more of amine per equivalent of carboxylic acid, and is usually 1 to 5 equivalents, preferably 1 to 3 equivalents, and more preferably 1 to 1.5 equivalents. An amine-carboxylate consisting of the added amine and the carboxylic acid represented by formula (3) is generated, and a mixture of the onium salt represented by formula (1), the amine-carboxylate, and the remaining amine is obtained.

[0139] The amine to be added may be added as an amine solution diluted with a solvent. Examples of the solvent include hexane, heptane, toluene, chloroform, dichloromethane, 2-ethylhexanol, cyclohexanol, 1-octanol, and ethyl acetate, and preferably chloroform, 2-ethylhexanol, cyclohexanol, and 1-octanol. The concentration of the amine solution is usually 0.01 g / L to 10.0 g / L, and preferably 0.1 g / L to 5.00 g / L.

[0140] The reaction conditions for generating an amine-carboxylate by adding an amine to a mixture containing an onium salt represented by formula (1) and a carboxylic acid represented by formula (3) are as follows: the temperature is 0°C to 100°C, and preferably 25°C to 80°C; and the reaction time is preferably 0.5 hours to 3 hours, and more preferably 1 hour to 2 hours, after completion of the addition of the amine, during which the mixture is stirred. In a preferred embodiment of the present invention, the mixture in step 1 further contains water and a solvent. The solvent may be a solvent for diluting the amine to be added, or may be added to the mixture in step 1 alone without being used to dilute the amine. The solvent contained in the mixture is preferably a solvent that undergoes phase separation with water. Examples of the solvent that undergoes phase separation with water include hexane, heptane, toluene, chloroform, dichloromethane, 2-ethylhexanol, cyclohexanol, 1-octanol, and ethyl acetate, and preferably include chloroform, 2-ethylhexanol, cyclohexanol, and 1-octanol. When the mixture in step 1 contains water and the solvent, the added amine forms an amine-carboxylate and is extracted mainly into the solvent layer. On the other hand, since the onium salt represented by formula (1) is present in the water layer, the amine-carboxylate is separated by separating the solvent layer, and the amount of the carboxylic acid represented by formula (3) is reduced or almost completely removed, resulting in a water layer containing the onium salt represented by formula (1). The carboxylic acid represented by formula (3) coexisting with the onium salt represented by formula (1) is difficult to remove by evaporation, but the water in the water layer containing the onium salt represented by formula (1) can be easily removed by evaporation, and the onium salt represented by formula (1) can be obtained. In the mixture containing the onium salt represented by formula (1) and the carboxylic acid represented by formula (3) before carrying out the production method or purification method of the present invention, the solubility of cellulose is greatly reduced due to the presence of the carboxylic acid represented by formula (3), but the solubility of cellulose can be greatly improved by carrying out the production method or purification method of the present invention. For example, in a mixture containing an onium salt represented by formula (1) and a carboxylic acid represented by formula (3), the solubility of cellulose can be greatly improved by removing 50% or more, 60% or more, 65% or more, 70% or more, 75% or more, 80% or more, 85% or more, 90% or more, 95% or more, or 100% of the carboxylic acid represented by formula (3).

[0141] Step (2) is a step of separating the onium salt represented by formula (1) from the amine-carboxylate produced in step (1). Examples of the separation method include separation (utilizing phase separation between water and a solvent) and crystallization (when the amine-carboxylate precipitates).

[0142] By the separation in step (2), a separated liquid containing the onium salt represented by formula (1) is obtained. When the separated liquid obtained contains residual amine, the residual amine can be distilled off by heating and / or reducing the pressure of the separated liquid obtained. In addition, when the amine is added as an amine solution diluted with a solvent, and the separated liquid containing the onium salt represented by formula (1) separated in step (2) contains the solvent, the solvent can be distilled off by heating and / or reducing the pressure of the separated liquid obtained.

[0143] In the present invention, the onium salt represented by formula (1) may be one type or a mixture of at least two types. Specific examples of the mixture of at least two types include a mixture of 1,3-dimethylimidazolium acetate and 1,3-diethylimidazolium acetate, a mixture of 1,3-dimethylimidazolium acetate and 1-ethyl-3-methylimidazolium acetate, a mixture of 1,3-diethylimidazolium acetate and 1-ethyl-3-methylimidazolium acetate, and a mixture of 1,3-dimethylimidazolium acetate, 1,3-diethylimidazolium acetate and 1-ethyl-3-methylimidazolium acetate.

[0144] In the present invention, the mixture containing the onium salt represented by formula (1) and the carboxylic acid represented by formula (3) may further contain water and / or a hydrophilic solvent, specific examples of which include methanol, ethanol, propanol, and ethylene glycol. The content of water and / or hydrophilic solvent is 0.1% by mass to 90% by mass, 1% by mass to 70% by mass, and preferably 5% by mass to 50% by mass, based on the total amount of the mixture containing the onium salt represented by formula (1), the carboxylic acid represented by formula (3), and the water and / or hydrophilic solvent being 100% by mass.

[0145] One embodiment of the present invention relates to a method for removing a carboxylic acid of formula (3) from a mixture containing an onium salt of formula (1) and a carboxylic acid of formula (3), the method comprising the following steps (1) and (2) for purifying the onium salt of formula (1): Process (1): A step of adding an amine to a mixture containing the onium salt represented by formula (1) and the carboxylic acid represented by formula (3) to produce an amine-carboxylate consisting of the amine and the carboxylic acid represented by formula (3). Process (2): A step of separating the onium salt represented by formula (1) from the amine-carboxylate produced in step (1) to obtain the onium salt represented by formula (1).

[0146] In the onium salt purification method of the present invention, the onium salt represented by formula (1) is the same as the onium salt represented by formula (1) in the above-mentioned onium salt production method. Also, in the onium salt represented by formula (1) in the onium salt purification method of the present invention, the carboxylate anion represented by formula (2) is the same as the carboxylate anion represented by formula (2) in the above-mentioned onium salt production method.

[0147] In the method for purifying an onium salt of the present invention, the carboxylic acid of formula (3) is the same as the carboxylic acid represented by formula (3) in the above-mentioned method for producing an onium salt.

[0148] In the method for purifying an onium salt of the present invention, the mixture containing the onium salt represented by formula (1) and the carboxylic acid represented by formula (3) is the same as the mixture containing the onium salt represented by formula (1) and the carboxylic acid represented by formula (3) in the above-mentioned method for producing an onium salt.

[0149] In the onium salt purification method of the present invention, the mixture containing the onium salt represented by formula (1) and the carboxylic acid represented by formula (3) is a mixture obtained by producing the onium salt represented by formula (1) using the carboxylic acid represented by formula (3), in which the carboxylic acid represented by formula (3) remains in the onium salt represented by formula (1). The amount of the remaining carboxylic acid represented by formula (3) is usually 1.5 equivalents or less per equivalent of the onium salt represented by formula (1).

[0150] In the method for purifying an onium salt of the present invention, step (1) is the same as step (1) in the above-mentioned method for producing an onium salt, and is a step of adding an amine to a mixture containing an onium salt represented by formula (1) and a carboxylic acid of formula (3) to produce an amine-carboxylate consisting of the amine and the carboxylic acid of formula (3).

[0151] The amine added in step (1) of the method for purifying an onium salt of the present invention is preferably the amine represented by formula (4) in the above-mentioned method for producing an onium salt.

[0152] In step (1) of the onium salt purification method of the present invention, the amount and preferred amount of the amine to be added to the mixture containing the onium salt represented by formula (1) and the carboxylic acid represented by formula (3) are the same as the amount of amine added in the above-mentioned method for producing an onium salt. In step (1) of the onium salt purification method of the present invention, an amine-carboxylate consisting of the added amine and a carboxylic acid of formula (3) is produced, as in step (1) of the above-described onium salt production method, and a mixture of the onium salt represented by formula (1), the amine-carboxylate, and the remaining amine is obtained.

[0153] The amine added in step (1) of the onium salt purification method of the present invention may be added as an amine solution diluted with a solvent, similar to the amine added in step (1) of the above-mentioned onium salt production method. Examples of the solvent include the same solvents as those used in step (1) of the above-mentioned production method, and the concentration of the amine solution may be the same as that in step (1) of the above-mentioned production method.

[0154] In step (1) of the onium salt purification method of the present invention, the reaction conditions for generating an amine-carboxylate by adding an amine to a mixture containing the onium salt represented by formula (1) and the carboxylic acid represented by formula (3) are the same as the reaction conditions in step (1) of the above-mentioned production method, such as the temperature conditions and reaction time.

[0155] In the method for purifying an onium salt of the present invention, step (2) is the same as step (2) in the above-mentioned method for producing an onium salt, and is a step for separating the onium salt represented by formula (1) from the amine-carboxylate salt produced in step (1). The method for separation is the same as the method used in step (2) in the above-mentioned method for producing an onium salt.

[0156] By the separation in step (2) in the onium salt purification method of the present invention, a separated liquid containing the onium salt represented by formula (1) is obtained. If the separated liquid contains residual amine or the solvent of the amine solution, the residual amine or the solvent can be distilled off by heating and / or reducing the pressure of the separated liquid, as in step (2) in the above-mentioned onium salt production method.

[0157] In the onium salt purification method of the present invention, the onium salt represented by formula (1) may be one type or a mixture of at least two types. The mixture of at least two types is the same as the mixture of at least two types of onium salt represented by formula (1) in the above-mentioned onium salt production method.

[0158] In the onium salt purification method of the present invention, the mixture containing the onium salt represented by formula (1) and the carboxylic acid represented by formula (3) may further contain water and / or a hydrophilic solvent, as in the above-mentioned method for producing an onium salt. Examples of the hydrophilic solvent include the same hydrophilic solvents as those used in the above-mentioned method for producing an onium salt, and the content of water and / or hydrophilic solvent is also the same as that in the above-mentioned method for producing an onium salt.

[0159] The onium salt produced by the method of the present invention can be used, for example, as a solvent for dissolving cellulose and as a carbon dioxide absorbent. EXAMPLES

[0160] The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples.

[0161] [Example 1] A 10% aqueous acetic acid solution (0.5 equivalents relative to the onium salt) and ion-exchanged water (6.00 g) were added to 1-ethyl-3-methylimidazolium acetate (2.00 g) (manufactured by Tokyo Chemical Industry Co., Ltd.) to prepare a mixture of 1-ethyl-3-methylimidazolium acetate and acetic acid. 1 The integral value of the peak derived from acetic acid was confirmed by 1 H NMR. 1 As a result of H NMR analysis, the integral value of the peaks representing acetate ions and methyl groups derived from acetic acid based on 1.38-1.44 ppm (m, 3H) was 4.67. Note that acetic acid used was that manufactured by Junsei Chemical Co., Ltd. Thereafter, 2-ethylhexanol (4.00 g) (manufactured by Junsei Chemical Co., Ltd.) and amines of the structures shown in Evaluation Examples 1 to 6 in Table 1 (1.5 equivalents relative to 1-ethyl-3-methylimidazolium acetate) were added, and the mixture was stirred and allowed to stand (80° C., 1 hour each). The mixture was separated into an upper layer containing acetic acid, amines, and 2-ethylhexanol, and a lower layer containing 1-ethyl-3-methylimidazolium acetate. After separation, the lower layer was 1 The 1 H NMR analysis confirmed the integral value of the peak derived from acetic acid based on 1.38-1.44 ppm (m, 3H). The acetic acid removal rate (%) was calculated from the integral value using the following formula. Acetic acid removal rate (%)=(1−(integral value−3.00) / (4.67−3.00))×100 In addition, in Evaluation Example 3, since the peak derived from dicyclohexylamine overlaps with the peak derived from acetic acid, the removal rate was calculated after removing the 2H portion derived from the amine. The results are shown in Table 1. The onium salts obtained using the amines of Evaluation Examples 1 to 6 are those from which acetic acid has been removed, and therefore can all improve the solubility of cellulose compared to the onium salt before removal of acetic acid. In particular, the onium salts obtained using the amines of Evaluation Examples 1 to 5 are preferred as onium salts that improve the solubility of cellulose.

[0162] [Table 1]

[0163] [Example 2] A 10% aqueous acetic acid solution (0.5 equivalents relative to the onium salt) and ethylene glycol (6.00 g) (Tokyo Chemical Industry Co., Ltd.) were added to 1-ethyl-3-methylimidazolium acetate (2.00 g) (Tokyo Chemical Industry Co., Ltd.) to prepare a mixture of 1-ethyl-3-methylimidazolium acetate and acetic acid. 1 The integral value of the peak derived from acetic acid was confirmed by 1 H NMR. 1 As a result of H NMR analysis, the integral value of the peaks representing acetate ions and methyl groups derived from acetic acid based on 1.38-1.44 ppm (m, 3H) was 4.67. Note that acetic acid used was that manufactured by Junsei Chemical Co., Ltd. Thereafter, 2-ethylhexanol (4.00 g) (manufactured by Junsei Chemical Co., Ltd.) and amines of the structures shown in Evaluation Examples 7 and 8 in Table 2 (1.5 equivalents relative to 1-ethyl-3-methylimidazolium acetate) were added, and the mixture was stirred and allowed to stand (80° C., 1 hour each). The mixture was separated into an upper layer containing acetic acid, amines, and 2-ethylhexanol, and a lower layer containing 1-ethyl-3-methylimidazolium acetate. After separation, the lower layer was 1 The 1 H NMR analysis confirmed the integral value of the peak derived from acetic acid based on 1.38-1.44 ppm (m, 3H). The acetic acid removal rate (%) was calculated from the integral value using the following formula. Acetic acid removal rate (%) = (1-(integral value-3.00) / (4.67-3.00)) x 100 The results are shown in Table 2. The onium salts obtained using the amines of Evaluation Examples 7 and 8 have had acetic acid removed, and therefore can improve the solubility of cellulose compared to the onium salt before removal of acetic acid.

[0164] [Table 2]

[0165] [Example 3] A 10% aqueous carboxylic acid solution (0.5 equivalents relative to the onium salt) of each carboxylic acid shown in Evaluation Examples 9 to 12 in Table 3 and ion-exchanged water (6.00 g) were added to an onium salt (2.00 g) of each structure shown in Synthesis Examples 1 to 4 below to prepare a mixture of the onium salt of each structure and each carboxylic acid,1 The integral values ​​of the peaks derived from carboxylic acids were confirmed by H NMR. In Evaluation Examples 9 to 11, the peaks at the 4th and 5th positions of the imidazolium ring were used as the reference, and in Evaluation Example 12, the integral values ​​of the peaks representing each carboxylate ion and the methyl group derived from carboxylic acid were used as the reference peak of the terminal methyl group of diethyl as the reference. These values ​​are shown in Table 3 as "integral values ​​before treatment". Then, 2-ethylhexanol (4.00 g) (manufactured by Junsei Chemical Co., Ltd.) and oleylamine (1.5 equivalents relative to the onium salt) were added, and the mixture was stirred and allowed to stand (80° C., 1 hour each). The mixture was separated into an upper layer containing each carboxylic acid, oleylamine, and 2-ethylhexanol, and a lower layer containing the onium salt of each structure. After separation, the lower layer was 1 Analysis was performed by H NMR, and the integral values ​​of the peaks derived from each carboxylic acid were confirmed using the peaks at the 4th and 5th positions of the imidazolium ring as the reference for Evaluation Examples 9 to 11, and using the peak of the terminal methyl group of diethyl as the reference for Evaluation Example 12. The removal rate (%) of carboxylic acid was calculated from the integral value according to the following formula. Carboxylic acid removal rate (%) = (1-(integral value-3.00) / (integral value before treatment-3.00)) x 100 The results are shown in Table 3. The onium salts obtained using the amines of Evaluation Examples 9 to 12 have had acetic acid removed, and therefore can improve the solubility of cellulose compared to the onium salt before removal of acetic acid.

[0166] [Table 3]

[0167] [Synthesis Example 1] [Synthesis of 1-ethyl-3-methylimidazolium propionate] Ion-exchanged water (50.1 g) was added to 1-ethyl-3-methylimidazolium acetate (5.11 g) (Tokyo Chemical Industry Co., Ltd.) to prepare an aqueous solution. The aqueous solution was passed through ion-exchange resin (Wako Pure Chemical Industries, No. 8 (OH type)) (22.7 g) to obtain 1-ethyl-3-methylimidazolium hydroxide. After measuring the concentration by neutralization titration, propionic acid (1.97 g) (Junsei Chemical) was added to make an equivalent amount. After concentrating and drying, 1-ethyl-3-methylimidazolium propionate was obtained.

[0168] [Synthesis Example 2] [Synthesis of 1-ethyl-3-methylimidazolium methoxyethoxypropionate] Ion-exchanged water (50.5 g) was added to 1-ethyl-3-methylimidazolium acetate (5.10 g) (Tokyo Chemical Industry Co., Ltd.) to prepare an aqueous solution. The aqueous solution was passed through ion-exchange resin (Wako Pure Chemical Industries, No. 8 (OH type)) (22.8 g) to obtain 1-ethyl-3-methylimidazolium hydroxide salt. After measuring the concentration by neutralization titration, methoxyethoxypropionic acid (0.03 g) was added to make an equivalent amount. After concentrating and drying, 1-ethyl-3-methylimidazolium methoxyethoxypropionate was obtained.

[0169] [Synthesis Example 3] [Synthesis of 1-methyl-3-methoxyethoxyethylimidazolium acetate] Acetonitrile (4.01 g) and 1-bromo-2-(2-methoxyethoxy)ethane (5.95 g, 30.4 mol) were added to 1-methylimidazole (2.51 g, 30.4 mol) and reacted for 24 hours at 80° C. After completion of the reaction, the mixture was concentrated to dryness to obtain 1-methyl-3-methoxyethoxyethylimidazolium bromide. The obtained 1-methyl-3-methoxyethoxyethylimidazolium bromide (9.52 g) (manufactured by Tokyo Chemical Industry Co., Ltd.) was added with ion-exchange water (110 g) to form an aqueous solution. The aqueous solution was passed through an ion-exchange resin (manufactured by Wako Pure Chemical Industries, No. 8 (OH type)) (62.0 g) to obtain 1-methyl-3-methoxyethoxyethylimidazolium hydroxide salt. After measuring the concentration by neutralization titration, acetic acid (2.06 g) (manufactured by Junsei Chemical Co., Ltd.) was added to make an equivalent amount. After concentrating and drying, 1-methyl-3-methoxyethoxyethylimidazolium acetate salt was obtained.

[0170] [Synthesis Example 4] [Synthesis of N,N-diethyl-N-methyl-N-methoxyethylammonium methoxyacetate] In a 500 mL autoclave, 49.8 g (0.38 mol) of N,N-diethyl-N-(2-methoxyethyl)amine, 102.8 g (1.14 mol) of dimethyl carbonate, and 24.2 g of methanol were placed, and the reaction was carried out for 30 hours while adjusting the pressure inside the autoclave to 0.3 to 0.4 MPa by degassing the autoclave at 130°C. The reaction solution was cooled to room temperature, and 118.6 g of a methanol solution of N,N-diethyl-N-methyl-N-methoxyethylammonium methyl carbonate was obtained. 34.0g (0.38mol) of methoxyacetic acid was added dropwise to 118.6g of a methanol solution of N,N-diethyl-N-methyl-N-methoxyethylammonium methyl carbonate, and the mixture was reacted at room temperature for 1 hour. The reaction solution was concentrated and dried to obtain N,N-diethyl-N-methyl-N-methoxyethylammonium methoxyacetate (89.0g).

[0171] [Example 4] <Acetic acid removal> 10% acetic acid aqueous solution (0.5 equivalents relative to the onium salt) and ion-exchanged water (59.32 g) were added to 1-ethyl-3-methylimidazolium acetate (42.02 g) (manufactured by Tokyo Chemical Industry Co., Ltd.). Hereinafter, this is referred to as the reaction solution. A portion of the reaction solution was concentrated, 1 The integral value of the peak derived from acetic acid was confirmed by 1 H NMR analysis, and a cellulose dissolution test was also performed. 1As a result of H NMR analysis, the integral value of the peaks representing acetate ions and methyl groups derived from acetic acid was 3.76, based on the peak at 1.38-1.44 ppm (m, 3H). The reaction solution was used as a comparative example. The acetic acid used was manufactured by Junsei Chemical Co., Ltd. Then, 2-ethylhexanol (12.00 g) (manufactured by Junsei Chemical Co., Ltd.) and amines (1.5 equivalents relative to the onium salt) having structures shown in Table 4 were added to the reaction solution (25.06 g), and the mixture was stirred and allowed to stand (80° C., 1 hour each). After separation, the lower layer was concentrated, 1 H NMR analysis and a dissolution test were carried out. These are hereinafter referred to as Evaluation Examples 13 to 18. 1 In the H NMR analysis, the integral value of the peak derived from acetic acid was confirmed based on the peak at 1.38-1.44 ppm (m, 3H). The removal rate (%) of acetic acid was calculated from the integral value. The formula is as follows: Acetic acid removal rate (%) = (1-(integral value-3.00) / (3.76-3.00)) x 100 In addition, in Evaluation Example 15, since the peak derived from dicyclohexylamine overlaps with the peak derived from acetic acid, the removal rate was calculated after removing the 2H component derived from the amine. The results are shown in Table 5. <Dissolution test> In the dissolution test, the dissolution of microcrystalline cellulose (15 wt% vs. concentrated liquid) (Avicel (registered trademark) PH-101, manufactured by Sigma-Aldrich Co. LLC) was confirmed at 25°C. The concentrated solution of the reaction solution (Comparative Example 1) and the concentrated solutions (1.0 g) of Evaluation Examples 13 to 18 were placed in test tubes, and microcrystalline cellulose (15 wt% vs. concentrated solution) was added at 25°C and stirred. After 24 hours, the dissolution of the microcrystalline cellulose was visually confirmed. Crystalline cellulose that was completely dissolved was marked with an ◯, and that was not completely dissolved was marked with an ×. The dissolution results are shown in Table 5.

[0172] [Table 4]

[0173] [Table 5] [Industrial Applicability]

[0174] According to the present invention, there can be provided a method for producing an onium salt that does not contain a carboxylic acid or an onium salt in which the carboxylic acid content is reduced to such an extent that sufficient solubility of cellulose in the onium salt is obtained. Furthermore, according to the present invention, a method for purifying an onium salt can be provided, which removes a carboxylic acid contained in the onium salt, or reduces the content of the carboxylic acid to an extent that sufficient solubility of cellulose in the onium salt can be obtained.

Claims

1. A method for producing an onium salt represented by formula (1), comprising obtaining an onium salt represented by formula (1) from a mixture containing an onium salt represented by formula (1) and a carboxylic acid represented by formula (3), the method comprising the steps (1) and (2): Formula (1): 【Chemistry 1】 (In formula (1), A + represents any one of pyridinium, ammonium, and imidazolium; X - is a carboxylate anion represented by the following formula (2): Formula (2): 【Chemistry 2】 (In formula (2), R 1 represents a hydrocarbon group having 1 to 12 carbon atoms, which may contain a heteroatom and / or a double bond. Formula (3): 【Chemistry 3】 (In formula (3), R 2 represents a hydrocarbon group having 1 to 12 carbon atoms, which may contain a heteroatom and / or a double bond; R 1 It may be the same as.) Process (1): A step of adding an amine to a mixture containing the onium salt represented by formula (1) and the carboxylic acid represented by formula (3) to produce an amine-carboxylate consisting of the amine and the carboxylic acid represented by formula (3). Process (2): A step of separating the onium salt represented by formula (1) from the amine-carboxylate produced in step (1) to obtain the onium salt represented by formula (1).

2. The method for producing an onium salt according to claim 1, wherein the amine added in the step (1) is an amine represented by the following formula (4): Formula (4): 【Chemistry 4】 (In formula (4), R 3 , R 4 and R 5 may be the same or different and are a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms, and the hydrocarbon group may contain a double bond and may contain a branched structure and / or a ring structure. 3 , R 4 and R 5 The total number of carbon atoms contained in each of is 8 or more.)

3. The method for producing an onium salt according to claim 1, wherein the onium salt represented by the formula (1) is of at least two types.

4. The method for producing an onium salt according to claim 1, wherein the mixture containing the onium salt represented by the formula (1) and the carboxylic acid represented by the formula (3) further contains water and / or a hydrophilic solvent.

5. The method for producing an onium salt according to claim 1, wherein the amine added in the step (1) is an amine solution diluted with a solvent.

6. A method for purifying an onium salt represented by the following formula (1) by removing a carboxylic acid of the following formula (3) from a mixture containing the onium salt represented by the following formula (1) and a carboxylic acid of the following formula (3), the method comprising the following steps (1) and (2): Formula (1): 【Chemistry 5】 (In formula (1), A + represents any one of pyridinium, ammonium, and imidazolium; X - is a carboxylate anion represented by the following formula (2): Formula (2): 【Chemistry 6】 (In formula (2), R 1 represents a hydrocarbon group having 1 to 12 carbon atoms, which may contain a heteroatom and / or a double bond. Formula (3): 【Chemistry 7】 (In formula (3), R 2 represents a hydrocarbon group having 1 to 12 carbon atoms, which may contain a heteroatom and / or a double bond; R 1 It may be the same as.) Process (1): A step of adding an amine to a mixture containing the onium salt represented by formula (1) and the carboxylic acid represented by formula (3) to produce an amine-carboxylate consisting of the amine and the carboxylic acid represented by formula (3). Process (2): A step of separating the onium salt represented by formula (1) from the amine-carboxylate produced in step (1) to obtain the onium salt represented by formula (1).

7. The method for purifying an onium salt according to claim 6, wherein the amine added in the step (1) is an amine represented by the following formula (4): Formula (4): 【Chemistry 8】 (In formula (4), R 3 , R 4 and R 5 may be the same or different and are a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms, and the hydrocarbon group may contain a double bond and may contain a branched structure and / or a ring structure. 3 , R 4 and R 5 The total number of carbon atoms contained in each of is 8 or more.)

8. The method for purifying an onium salt according to claim 6 , wherein the onium salt represented by the formula (1) is of at least two types.

9. The method for purifying an onium salt according to claim 6 , wherein the mixture containing the onium salt represented by the formula (1) and the carboxylic acid represented by the formula (3) further contains water and / or a hydrophilic solvent.

10. 7. The method for purifying an onium salt according to claim 6, wherein the amine added in the step (1) is an amine solution diluted with a solvent.

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