WO2014051057A1

WO2014051057A1 - Gelling agent

Info

Publication number: WO2014051057A1
Application number: PCT/JP2013/076276
Authority: WO
Inventors: 達生丸山
Original assignee: 国立大学法人神戸大学; 日産化学工業株式会社
Priority date: 2012-09-27
Filing date: 2013-09-27
Publication date: 2014-04-03
Also published as: JPWO2014051057A1; JP6304820B2

Abstract

The purpose of the present invention is to provide a gelling agent that enables an ionic liquid to be converted into a gel, even if the concentration of the ionic liquid is low, thereby providing an electrolyte gel having a low rate of decrease of electrical conductivity. This ionic liquid gelling agent is characterized by containing a compound represented by general formula (1). [In formula (1), R¹ to R³ are each the same or different, and represent a linear or branched alkyl group with a carbon number of one to nine. However, a methylene group (-CH₂-) included in the linear or branched alkyl groups of R¹ to R³ may be replaced by a sulfide bond (-S-). R⁴ to R⁶ are each the same or different, and represent a linear or branched alkyl group with a carbon number of one to four.]

Description

Gelling agent

The present invention relates to a gelling agent for an ionic liquid and a method for producing an electrolyte gel using the gelling agent and the ionic liquid.

Conventionally, gelling agents have been used as those having the function of gelling or solidifying liquids such as water and oil (animal and vegetable oils, esters, polyols, ethers, alcohols, hydrocarbons, etc.). A low molecular gelling agent and a high molecular gelling agent are used. Whether the gelling agent is a low molecular gelling agent (for example, a gelling agent having a molecular weight of less than 900 g / mol) or a high molecular gelling agent (for example, a gelling agent having a molecular weight of 900 g / mol or more). Regardless, after being dissolved in liquids, a three-dimensional network structure is formed. When the liquids are taken into the three-dimensional network structure, the liquids are gelled.

The low molecular weight gelling agent self-assembles in a liquid by non-covalent interaction to form a fibrous structure. This fiber structure is entangled to form a three-dimensional network structure. Gelation is said to occur when liquids are taken into the three-dimensional network structure of the fiber structure. Gelation with a low molecular weight gelling agent includes desolvation of the low molecular weight gelling agent in a liquid, non-covalent interaction between low molecular weight gelling agents (for example, hydrogen bond or π-π bond), A phenomenon involving the self-organization of low molecular weight gelators based on non-covalent interactions (a phenomenon in which randomly dispersed molecules form an ordered structure spontaneously under a given external environment). is there. Thus, gelation with a low molecular weight gelling agent is a phenomenon involving multiple factors (desolvation, non-covalent interaction, self-assembly). Development is slower than gelling agents, and there are few known low-molecular gelling agents (Patent Documents 2 and 3, Non-Patent Document 1).

On the other hand, an ionic liquid is a salt formed from an organic anion derived from a strong acid and an organic cation derived from a weak base, and is also called a room temperature molten salt or an ionic liquid. Unlike general salts, ionic liquids are liquid even at room temperature and are not compatible with water or oil (organic solvent). Therefore, ionic liquids are attracting attention as the third liquid after water and oil (organic solvent). Yes. Ionic liquids exhibit flame retardancy, non-volatility, and ionic conductivity, and do not decompose even at high temperatures of several hundred degrees, so they can be used as organic reaction solvents and lubricants with low environmental impact instead of conventional organic solvents. Is being considered.

An ionic liquid is a liquid that is particularly excellent in non-volatile properties and ionic conductivity, and can be used for a fuel cell or a secondary battery because it can pass a current without adding a supporting electrolyte and has a wide potential window. It is attracting attention as a useful electrolyte. In fuel cells and secondary batteries, electrolyte leakage and self-discharge are a problem. For the purpose of suppressing these problems, investigations have conventionally been made to gel the electrolyte into various electrolyte gels. ing. Further, in the development of artificial actuators, investigations have been made on gel materials having characteristics of electrical conductivity and flexible elasticity (Patent Document 1, Non-Patent Documents 2, 3, and 4).

JP 2011-236328 A (first to third pages) JP 2000-72736 A (pages 1 and 2) JP 2005-533134 A (pages 1 to 3)

An ionic liquid is a salt composed of an organic anion and an organic cation and exists as a liquid at room temperature. Therefore, conventionally known polymer gelling agents are difficult to dissolve or disperse in ionic liquids, and it is difficult to gel ionic liquids using polymer gelling agents. Moreover, in the polymer gelling agent designed so that an ionic liquid may be gelatinized, in order to improve mechanical strength, a crosslinked structure may be partially introduced in the case of gelatinization. However, when a crosslinked structure is formed, there is a problem that the electrical conductivity and ionic conductivity of the gel obtained by gelling the ionic liquid are smaller than the electrical conductivity or ionic conductivity of the ionic liquid itself.

On the other hand, when a low molecular weight gelling agent is applied to an ionic liquid, the low molecular weight gelling agent must exhibit a non-covalent interaction in the presence of an interaction between an organic anion and an organic cation of the ionic liquid. is there. At the same time, in order to obtain a state in which the ionic liquid is taken into the three-dimensional network structure, the low-molecular gelling agent must be uniformly dispersed or dissolved in the ionic liquid. For this reason, in the application of a low-molecular gelling agent in an ionic liquid, it is necessary to have a contradictory property of sufficient noncovalent interaction and dispersibility or solubility in the ionic liquid. Therefore, as in Patent Documents 2 and 3 and Non-Patent Document 1, even low-molecular gelling agents that exhibit gelling ability in water or organic solvents do not always exhibit gelling ability with respect to ionic liquids. Therefore, it is difficult to predict the behavior of the low-molecular gelling agent.

Further, as described above, since the ionic liquid exists as a liquid due to the interaction between the organic anion and the organic cation, in order to gel the ionic liquid with the low molecular gelling agent, Patent Document 1 and Non-Patent Document As in 2-4, it was necessary to add many low molecular gelling agents. Moreover, in the gel formed with these low molecular gelling agents, there existed a problem that an electrical conductivity fell large rather than the electrical conductivity which the ionic liquid before gelatinization has.

As a result of intensive studies to solve the above problems, the present inventor was able to gel the ionic liquid even when the concentration of the gelling agent was low, using a predetermined gelling agent, and obtained The present invention was completed by finding that the rate of decrease in electrical conductivity of the electrolyte gel was low.

That is, the ionic liquid gelling agent according to the present invention is characterized by containing a compound represented by the general formula (1).

[In the formula (1), R ¹ to R ³ are the same or different and each represents a linear or branched alkyl group having 1 to 9 carbon atoms. However, the methylene group (—CH ₂ —) contained in the linear or branched alkyl group of R ¹ to R ³ may be replaced with a sulfide bond (—S—). R ⁴ to R ⁶ are the same or different and each represents a linear or branched alkyl group having 1 to 4 carbon atoms]

In the ionic liquid gelling agent of the present invention, R ¹ to R ³ are the same or different and are each selected from methyl group, 2-propyl group, 2-methylpropyl group, 1-methylpropyl group and methylthioethyl group. It is preferably one group selected from the group consisting of, and more preferably one group selected from the group consisting of a methyl group, a 2-propyl group, a 2-methylpropyl group, and a methylthioethyl group. R ⁴ to R ⁶ are preferably methyl groups.

The gelling agent for ionic liquid of the present invention is preferably used for producing an electrolyte gel by mixing with an ionic liquid. In the production of the electrolyte gel, it is preferable to heat and cool the mixture of the ionic liquid gelling agent of the present invention and the ionic liquid.

The ionic liquid forming the electrolyte gel includes an imidazolium ion, a pyridinium ion, a piperidinium ion, a pyrrolidinium ion, a phosphonium ion, an ammonium ion and a sulfonium ion, a halogen ion, a carboxylate ion, Sulfate ion, sulfonate ion, thiocyanate ion, nitrate ion, aluminate ion, borate ion, phosphate ion, amide ion, antimonate ion, imide ion, methide ion, amino acid ion, N-acyl acidic amino acid ion and N-acyl neutral amino acid An ionic liquid composed of an organic anion selected from the group consisting of ions is preferred.

More preferably, the ionic liquid forming the electrolyte gel is 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) amide, 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) amide, 1-hexyl-3-methylimidazolium bis (trifluoromethylsulfonyl) amide, 1-butylpyridinium bis (trifluoromethylsulfonyl) amide, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate and 1-butyl-3- It is one ionic liquid selected from the group consisting of methylimidazolium trifluoromethanesulfonate.

Further, as an electrolyte gel, inorganic sulfate, inorganic phosphate, hydroxylated inorganic salt, hexafluorophosphate inorganic salt, trifluorosulfonic acid inorganic salt, perchloric acid inorganic salt, tetrafluoroborate inorganic salt, bis (fluorosulfonyl) It is preferable to contain one or two salts selected from the group consisting of an imide inorganic salt, a bis (trifluoromethylsulfonyl) amide inorganic salt, and an inorganic cobalt salt.
The present invention also includes a compound represented by the general formula (1). In the compound of the present invention, each of R ¹ to R ³ is the same or different and is selected from the group consisting of a methyl group, a 2-propyl group, a 2-methylpropyl group, a 1-methylpropyl group, and a methylthioethyl group. It is preferably a group, more preferably one group selected from the group consisting of a methyl group, a 2-propyl group, a 2-methylpropyl group, and a methylthioethyl group. R ⁴ to R ⁶ are preferably methyl groups.

Also, the use of the compound represented by the general formula (1) for gelling an ionic liquid is also encompassed in the scope of the present invention.

The gelling agent for ionic liquid of the present invention can keep the gel structure stable while maintaining various characteristics of the ionic liquid, such as low vapor pressure, non-volatility, and high specific heat capacity. The electrolyte gel manufactured including the step of mixing the ionic liquid gelling agent and the ionic liquid of the present invention maintains the characteristics of the ionic liquid, particularly the electrical conductivity. For this reason, application to electrolyte materials and artificial actuators used for fuel cells and secondary batteries can be expected.

FIG. 1 is a photograph of an electrolyte gel using [bmim] [TFSA] as an ionic liquid in the electrolyte gel of Example 2 observed with a field emission scanning electron microscope (FE-SEM) at a magnification of 2,000 times. It is. FIG. 2 shows an electrolyte gel using [bmim] [CF ₃ SO ₃ ] as an ionic liquid among the electrolyte gels of Example 2 using a field emission scanning electron microscope (FE-SEM) at a magnification of 2,000 times. It is an observed photograph.

1. Gelling agent 1-1. Gelling agent (1)
The gelling agent of the ionic liquid of the present invention is characterized by containing a compound represented by the general formula (1) (hereinafter sometimes referred to as “gelling agent (1)”).

[In Formula (1), R ¹ to R ³ are the same or different and each represents a linear or branched alkyl group having 1 to 9 carbon atoms. However, the methylene group (—CH ₂ —) contained in the linear or branched alkyl group of R ¹ to R ³ may be replaced with a sulfide bond (—S—). R ⁴ to R ⁶ are the same or different and each represents a linear or branched alkyl group having 1 to 4 carbon atoms]

Examples of the linear or branched alkyl group having 1 to 9 carbon atoms in R ¹ to R ³ include a methyl group, an ethyl group, a propyl group, a butyl group, a methylpropyl group, a pentyl group, a methylbutyl group, and dimethylpropyl. Group, hexyl group, methylpentyl group, dimethylbutyl group, heptyl group, methylhexyl group, dimethylpentyl group, ethylpentyl group, octyl group, methylheptyl group, dimethylhexyl group, ethylhexyl group, trimethylpentyl group, methylethylpentyl group , Nonyl group, methyloctyl group, dimethylheptyl group, ethylheptyl group, trimethylhexyl group, methylethylhexyl group and the like.

The linear or branched alkyl group represented by R ¹ to R ³ is preferably a linear or branched alkyl group having 1 to 6 carbon atoms, and more preferably a linear or branched alkyl group having 1 to 5 carbon atoms. A branched alkyl group, more preferably a linear or branched alkyl group having 1 to 4 carbon atoms, and particularly preferably a methyl group, a 2-propyl group, a 2-methylpropyl group, or a 1-methylpropyl group. One group selected from the group consisting of a group and an n-butyl group.

In the gelling agent (1) of the present invention, since the carbon number of the linear or branched alkyl group of R ¹ to R ³ is 1 or more, the gelling agent (1) non-covalent bonding between molecules It has a moderate effect and dissolves in ionic liquids. However, if the alkyl group of R ¹ to R ³ has too many carbon atoms, the noncovalent interaction between the gelling agent (1) molecules is inhibited, and the ionic liquid cannot be gelled. Therefore, the number of carbon atoms in the alkyl group of R ¹ to R ³ is preferably within the above range.

Examples of the group in which the methylene group (—CH ₂ —) of the linear or branched alkyl group of R ¹ to R ³ is replaced by a sulfide bond (—S—) include, for example, a methylthiomethyl group, a methylthioethyl group, a methylthio group Alkyl groups having a methylthio group such as propyl group and methylthiobutyl group; alkyl groups having an ethylthio group such as ethylthiomethyl group, ethylthioethyl group and ethylthiopropyl group; propylthio such as propylthiomethyl group and propylthioethyl group An alkyl group having a group; an alkyl group having a butylthio group such as a butylthiomethyl group. The alkylthio group is a hydrophilic group and has a high polarity and therefore contributes to noncovalent interaction (hydrogen bond). The closer the sulfide bond is to the end of the gelling agent (1) molecule, the more noncovalent It is considered that a bonding interaction (hydrogen bond) is likely to occur. Accordingly, the group in which the methylene group (—CH ₂ —) of the linear or branched alkyl group of R ¹ to R ³ is replaced by a sulfide bond (—S—) is preferably an alkyl group having a methylthio group or An alkyl group having an ethylthio group, more preferably an alkyl group having a methylthio group, and particularly preferably a methylthioethyl group.

In the gelling agent (1) of the present invention, the group in which the methylene group (—CH ₂ —) of the linear or branched alkyl group of R ¹ to R ³ is replaced by a sulfide bond (—S—) Agent (1) It is preferable that the number of carbon atoms is 3 or more from the viewpoint of setting the non-covalent interaction between molecules within an appropriate range. However, in the group in which the methylene group (—CH ₂ —) of the linear or branched alkyl group of R ¹ to R ³ is replaced with a sulfide bond (—S—), the sulfur atom is also calculated as having 1 carbon atom. Shall. When the carbon number of the methylene group (—CH ₂ —) of the alkyl group of R ¹ to R ³ is replaced by a sulfide bond (—S—) is 3 or more, the gelling agent (1) non-covalent between molecules The binding interaction is moderate and dissolves in ionic liquids. However, if the methylene group (—CH ₂ —) of the alkyl group of R ¹ to R ³ is replaced with a sulfide bond (—S—), the noncovalent interaction is reduced by the gelling agent ( 1) It tends to occur at the end of the molecule, the formation of an ordered structure (self-assembly) is inhibited, and the ionic liquid cannot be gelled. Therefore, the carbon number of the group in which the methylene group (—CH ₂ —) of the alkyl group of R ¹ to R ³ is replaced by a sulfide bond (—S—) is preferably 6 or less, and preferably 5 or less. More preferably, it is more preferably 4 or less.

Examples of the linear or branched alkyl group having 1 to 4 carbon atoms in R ⁴ to R ⁶ include those listed as the linear or branched alkyl group having 1 to 4 carbon atoms in R ¹ to R ^3. The same can be mentioned, preferably a linear or branched alkyl group having 1 to 3 carbon atoms, more preferably a linear or branched alkyl group having 1 to 2 carbon atoms, particularly preferably. Is a methyl group.

In the gelling agent (1) of the present invention, the linear or branched alkyl group of R ⁴ to R ⁶ has 1 or more carbon atoms and is electrically stable. Suitable as The larger the carbon number of the alkyl group of R ⁴ to R ⁶ is, the more stable the gelling agent (1) is. However, if the number of carbon atoms of the alkyl group of R ⁴ to R ⁶ is too large, the gelling agent (1) The non-covalent interaction between each other is inhibited, and the ionic liquid cannot be gelled. Therefore, the number of carbon atoms in the groups R ⁴ to R ⁶ is preferably within the above range.

In the gelling agent (1) of the present invention, one amide bond and one ester bond are bonded to the 1,3,5-position of the benzene ring through one carbon atom, and defined by R ¹ to R ⁶ Can be dissolved in the ionic liquid, and even in the ionic liquid, it can efficiently self-assemble to form a fibrous aggregate, A structure can be formed. By the self-assembly, the gelling agent (1) of the present invention can gel the ionic liquid.

Since the ionic liquid is a salt composed of an organic anion and an organic cation that exists as a liquid at room temperature, the self-organization behavior of the gelling agent in the ionic liquid depends on the hydrophilicity of the substituent. It varies greatly depending on the degree of property and hydrophobicity. Therefore, it is difficult to predict the self-organization behavior of the gelling agent.

As the gelling agent (1), a compound represented by the formula (1-1) (hereinafter sometimes referred to as gelling agent (1-1)) is preferable.

[In the formula (1-1), R ¹¹ represents a linear or branched alkyl group having 1 to 9 carbon atoms. However, the methylene group (—CH ₂ —) contained in the linear or branched alkyl group of R ¹¹ may be replaced with a sulfide bond (—S—). R ¹² represents a linear or branched alkyl group having 1 to 4 carbon atoms]

The linear or branched alkyl group having 1-9 carbon atoms in R ^11, wherein include the same groups as those of the alkyl group of R ¹ ~ R ^3, linear or branched R ¹¹ As the group in which the methylene group (—CH ₂ —) of the chain alkyl group is replaced with a sulfide bond (—S—), the methylene group (—CH ₂ —) of the alkyl group of R ¹ to R ³ is a sulfide bond ( Examples thereof include the same groups as those replaced with -S-).

Examples of the linear or branched alkyl group having 1 to 4 carbon atoms for R ¹² include the same groups as those exemplified as the alkyl group for R ⁴ to R ⁶ .

The ionic liquid that forms an electrolyte gel together with the gelling agent of the present invention is preferably an ionic liquid composed of an organic anion and an organic cation. Examples of the organic anion include imidazolium ion, pyridinium ion, piperidinium ion, pyrrolidini. An organic cation (preferably one organic cation) selected from the group consisting of a humium ion, a phosphonium ion, an ammonium ion, and a sulfonium ion can be preferably used. , Thiocyanate ion, nitrate ion, aluminate ion, borate ion, phosphate ion, amide ion, antimonate ion, imide ion, methide ion, amino acid ion The organic anion selected from the group consisting of N- acyl acidic amino acid ions and N- acyl neutral amino acid ion (preferably an organic anion of 1) can be preferably used. Each of the organic cation and the organic anion may have a substituent. The organic cation is more preferably one organic cation selected from the group consisting of an imidazolium ion, a pyridinium ion, and an ammonium ion, and more preferably an imidazolium ion or a pyridinium ion. The organic anion is more preferably one organic cation selected from the group consisting of a sulfonate ion, a borate ion, a phosphate ion, and an amide ion, and still more preferably a sulfonate ion or an amide ion.

As the ionic liquid, an imidazolium ion is used as an organic cation, an ionic liquid using an amide ion as an organic anion, a pyridinium ion as an organic cation, an ionic liquid using an amide ion as an organic anion, and an imidazolium as an organic cation Ionic liquids using ions and sulfonate ions as organic anions are preferred, such as 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) amide, 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) ) Amide, 1-hexyl-3-methylimidazolium bis (trifluoromethylsulfonyl) amide, 1-butylpyridinium bis (trifluoromethylsulfonyl) amide, 1-ethyl-3-methylimidazole 1 ionic liquid is more preferably selected from the ium trifluoromethanesulfonate and 1-butyl-3-methylimidazolium group consisting trifluoromethanesulfonate.

In the ionic liquid gelling agent of the present invention, the gelling agent (1) is preferably contained in an amount of 50% by mass or more and 100% by mass or less with respect to 100% by mass of the total amount of the ionic liquid gelling agent. It is preferably 90% by mass or more and 100% by mass or less, more preferably 95% by mass or more and 100% by mass or less, and particularly preferably 100% by mass. That is, it is preferable that the gelling agent of the ionic liquid does not contain any other components other than the gelling agent (1).

1-2. Production method of gelling agent (1) The gelling agent (1) of the present invention can be easily synthesized by the following reaction.

In the amino acid alkyl ester (H ₂ N—CH (R ^a ) —COOR ^b ) represented by the general formula (A), R ^a represents the same group as R ¹ to R ³ in the general formula (1), R ^b represents the same group as R ⁴ to R ⁶ in the general formula (1). The amino acid alkyl ester (H ₂ N—CH (R ^a ) —COOR ^b ) represented by the general formula (A) can be synthesized by a conventionally known method, for example, H ₂ N—CH in the presence of an acid catalyst. It can be obtained by dehydrating condensation of an amino acid represented by (R ^a ) —COOH and an alcohol represented by R ^b OH.

The gelling agent (1) of the present invention can be obtained by reacting the amino acid alkyl ester with the benzenecarboxylic acid chloride represented by the general formula (B). In the general formula (B), X ¹ to X ³ represent a halogen atom, preferably a chlorine atom. The method and conditions are not particularly limited. For example, an amino acid alkyl ester represented by the general formula (A) and a benzenecarboxylic acid chloride represented by the general formula (B) are mixed with a base such as triethylamine at a predetermined reaction equivalent. In the presence of, a condensation reaction may be carried out in a dry solvent. This reaction can be carried out at a temperature of 0 ° C. to 50 ° C. for 16 hours to 20 hours using an amino acid alkyl ester and benzene tricarboxylic acid chloride in a molar ratio of about 3: 1.

If unreacted raw materials and by-products remain in the reaction product, the reaction product can be purified by means such as distillation under reduced pressure or solvent fractionation. For example, purification of the reaction product is performed by washing with pure water, removing unreacted materials under reduced pressure, recrystallization with an organic solvent such as acetone, treatment with adsorbent such as activated clay, activated carbon, silica gel, alumina, etc. These may be applied alone or in combination as necessary. When the compound of the present invention is used as an ionic liquid gelling agent, a slight amount (less than several mass%) of unreacted raw materials such as benzenecarboxylic acid and / or amino acid alkyl ester and by-products are particularly mixed. There is no problem.

1-3. Other Components The ionic liquid gelling agent of the present invention may contain a component (2) other than the gelling agent (1). Examples of the component (2) include surfactants, swelling agents, antifreeze agents, viscosity modifiers, ionic strength modifiers, and the like. A conventionally well-known thing can be used for surfactant. The swelling agent plays a role of expanding the molecular assembly, and examples thereof include trimethylbenzene, triethylbenzene, and triisopropylbenzene.
In the ionic liquid gelling agent of the present invention, when the component (2) is contained, the content of the component (2) is 0.1% by mass or more and 50% by mass with respect to 100% by mass of the total amount of the ionic liquid gelling agent. % Is preferably 0.1% by mass or more and 10% by mass or less, and more preferably 1% by mass or more and 5% by mass or less.

2. Method for Producing Electrolyte Gel The method for producing an electrolyte gel of the present invention includes a step of mixing a gelling agent of the ionic liquid of the present invention and an ionic liquid.

As the ionic liquid used for the production of the electrolyte gel of the present invention, a conventionally known ionic liquid can be used. As the ionic liquid, an ionic liquid composed of an organic anion and an organic cation is preferable, and the organic anion is composed of an imidazolium ion, a pyridinium ion, a piperidinium ion, a pyrrolidinium ion, a phosphonium ion, an ammonium ion, and a sulfonium ion. One organic cation selected from the group can be preferably used, and examples of the organic cation include halogen ions, carboxylate ions, sulfate ions, sulfonate ions, thiocyanate ions, nitrate ions, aluminate ions, borate ions, phosphate ions, Consists of amide ion, antimonate ion, imide ion, methide ion, amino acid ion, N-acyl acidic amino acid ion and N-acyl neutral amino acid ion It can be preferably used one organic anion selected from. Examples of amino acids include aspartic acid, glutamic acid, proline, glycine, alanine, valine, leucine, isoleucine, and phenylalanine. N-acyl acidic amino acids and N-acyl neutral amino acids are these N-acyl derivatives. is there. In addition, an acetyl group is mentioned as an acyl group. Each of the organic cation and the organic anion may have a substituent.

Among the organic cations constituting the ionic liquid, the imidazolium ion includes 1,3-dimethylimidazolium ion, 1,3-diethylimidazolium ion, 1,3-dipropylimidazolium ion, 1-ethyl- 1,3-dialkylimidazolium ions such as 3-methylimidazolium ion, 1-methyl-3-propylimidazolium ion, 1-methyl-3-butylimidazolium ion, 1-isopropyl-3-propylimidazolium ion; 1,2,3-trimethylimidazolium ion, 1,2,3-triethylimidazolium ion, 1-ethyl-2,3-dimethylimidazolium ion, 1,2-dimethyl-3-propylimidazolium ion, 2- Such as ethyl-1,3-dimethylimidazolium ion , 2,3-trialkyl imidazolium ion; and the like. Examples of the pyridinium ion include N-alkylpyridinium ions such as N-methylpyridinium ion, N-ethylpyridinium ion, and N-propylpyridinium ion; 1-methyl-1-propylpyrrolidinium ion, 1-ethyl-1-methylpyrrole N-alkylpyrrolidinium ions such as dinium ions and 1-butyl-1-methylpyrrolidinium ions; Examples of the ammonium ion include tetraalkylammonium ions such as N, N, N-trimethyl-N-propylammonium and methyltrioctylammonium. Examples of the phosphonium ion include tetraalkylphosphonium ions such as tetramethylphosphonium ion, tetraethylphosphonium ion, tetrapropylphosphonium ion, tetrabutylphosphonium ion, trimethylethylphosphonium ion, and triethylmethylphosphonium ion. Examples of the sulfonium ion include trialkylsulfonium ions such as trimethylsulfonium ion, triethylsulfonium ion, tripropylsulfonium ion, tributylsulfonium ion, dimethylethylsulfonium ion, diethylmethylsulfonium ion, and dimethylpropylsulfonium ion. The organic cation constituting the ionic liquid is more preferably one organic cation selected from the group consisting of an imidazolium ion, a pyridinium ion, and an ammonium ion, and more preferably an imidazolium ion or a pyridinium ion. .

Among the organic anions constituting the ionic liquid, examples of the sulfonate ion include trifluoromethanesulfonate ion. Examples of borate ions include tetrafluoroborate ions. Examples of phosphate ions include hexafluorophosphate ions. Antimonate ions include hexafluoroantimonate ions. Examples of the imide ion include bis (trifluoromethylsulfonyl) imide ion, bis (fluorosulfonyl) imide ion, and nitrate ion. Examples of the amide ion include bis (trifluoromethylsulfonyl) amide ion. Examples of carboxylate ions include trifluoromethylcarboxylate ions and carboxylate ions. Moreover, a chloroaluminate ion is mentioned as an aluminate ion. The organic anion constituting the ionic liquid is more preferably one organic cation selected from the group consisting of a sulfonate ion, a borate ion, a phosphate ion, and an amide ion, and further preferably a sulfonate ion or an amide ion.

Further, the ionic liquid composed of the organic cation and the organic anion includes 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) amide, 1-butyl-3-methylimidazolium bis (trifluoromethyl). Ionic liquids using imidazolium ions as organic cations and amide ions as organic anions, such as sulfonyl) amide, 1-hexyl-3-methylimidazolium bis (trifluoromethylsulfonyl) amide; 1-butylpyridinium bis (tri Ionic liquids using pyridinium ions as organic cations such as fluoromethylsulfonyl) amide and amide ions as organic anions; 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methyl Using imidazolium ions as organic cations, such as imidazolium trifluoromethanesulfonate, ionic liquids using a sulfonate ion as the organic anion is particularly preferred.

In the present invention, an inorganic salt can be added to the ionic liquid. Examples of the inorganic salt include inorganic sulfate, inorganic phosphate, hydroxylated inorganic salt, hexafluorophosphate inorganic salt, trifluorosulfonic acid inorganic salt, perchloric acid inorganic salt, tetrafluoroborate inorganic salt, bis (fluorosulfonyl) An imide inorganic salt, a bis (trifluoromethylsulfonyl) amide inorganic salt, an inorganic cobalt salt, or the like is preferably used. The inorganic salt is more preferably Li ₂ SO ₄ , Li ₂ PO ₄ , LiOH, LiPF ₆ , CF ₃ SO ₃ Li, LiClO ₄ , LiBF ₄ , (CF ₃ SO ₂ ) ₂ NLi or LiCoO ₂ .

The content of the inorganic salt may be 0.01% by mass or more, more preferably 0.02% by mass or more, and still more preferably 0.05% by mass or more with respect to 100% by mass of the ionic liquid. May be. As the content of the inorganic salt is increased, an electrolyte gel having excellent conductivity can be obtained. Moreover, 0.2 mass% or less is preferable with respect to 100 mass% of ionic liquids, and, as for content of an inorganic salt, 0.15 mass% or less is more preferable, and 0.12 mass% or less is further more preferable. The smaller the content of the inorganic salt, the more easily the electrolyte gel can be obtained.

In the method for producing an electrolyte gel of the present invention, the content of the gelling agent of the ionic liquid of the present invention is preferably 0.1% by mass or more with respect to 100% by mass of the total amount of the obtained electrolyte gel. It is more preferably 5% by mass or more, and further preferably 1.0% by mass or more. The content of the gelling agent in the ionic liquid is preferably 5% by mass or less, more preferably 3% by mass or less, and more preferably 2.0% by mass with respect to 100% by mass of the total amount of the electrolyte gel obtained. More preferably, it is% or less. The content of the gelling agent of the present invention is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more with respect to 100 parts by mass of the ionic liquid, and 1 part by mass or more. More preferably. The content of the gelling agent of the present invention is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and more preferably 2 parts by mass or less with respect to 100 parts by mass of the ionic liquid. Is more preferable.

The more the content of the gelling agent in the ionic liquid, the easier it is to gel the ionic liquid, but if the content of the gelling agent is too much, there is a risk that the electrical conductivity when the electrolyte gel is made decreases. is there. In the electrolyte gel obtained by the production method of the present invention, if the content of the gelling agent of the ionic liquid is in the above range, the gelling ability and the electric conductivity of the electrolyte gel can be compatible.

The method of mixing the gelling agent and the ionic liquid is not particularly limited, and a conventionally known method such as a shaking method or a stirring method can be used. From the viewpoint of uniformly dissolving the gelling agent in the ionic liquid, the shaking method is preferred.

The method for producing an electrolyte gel of the present invention preferably further includes a step of heating and cooling the mixture of the gelling agent and the ionic liquid. The temperature for heating the mixture of the gelling agent and the ionic liquid is preferably 100 ° C. or higher and 250 ° C. or lower, more preferably 100 ° C. or higher and 200 ° C. or lower. When the heating temperature is less than 100 ° C., it is difficult to dissolve the gelling agent sufficiently in the ionic liquid and dissolve it uniformly. The higher the heating temperature, the better the solubility of the ionic liquid gelling agent of the present invention in the ionic liquid. However, if the heating temperature exceeds 250 ° C., the gelling agent may be decomposed, which is not preferable. .

In the present invention, the electrolyte gel is defined as a mixture of the ionic liquid and the gelling agent (1) that exhibits abnormal viscosity due to the effect of the gelling agent and loses fluidity. In the present invention, a plurality of ionic liquid gelling agents are self-assembled by non-covalent bonding between gelling agent molecules to form a fiber-like structure, and the fiber structure is entangled to form a three-dimensional network structure. Furthermore, it is considered that the electrolyte gel is formed by the ionic liquid being taken into the three-dimensional network structure. Examples of the non-covalent interaction include a hydrogen bond and a π-π bond.

In the method for producing an electrolyte gel of the present invention, the method for determining gelation is not particularly limited, and a conventionally known method can be used. For example, a falling ball method, a viscoelasticity measuring method, a test tube inversion method, or the like is used. Can do. In the present invention, the test tube inversion method is preferably used from the viewpoint of simplicity of equipment and the like. In the test tube inversion method, a reaction solution obtained by mixing an ionic liquid gelling agent and an ionic liquid is placed in a test tube, and gelled depending on whether the reaction solution flows when the test tube is turned upside down. Determine.

The gelling agent of the ionic liquid of the present invention can form a stable gel while maintaining various characteristics of the ionic liquid, such as high heat resistance and flame retardancy. For example, the electrical conductivity is as good as 0% or more and 25% or less, more preferably 0% or more and 10% or less, in terms of a decrease in electrical conductivity compared to the original electrical conductivity. For this reason, the gelling agent of the present invention and the electrolyte gel obtained by the production method of the present invention are electrolytes for fuel cells, secondary batteries, dye-sensitized solar cells, artificial actuators, electrochemical sensors, light-emitting display devices, impacts It can be used as an absorbent material (for example, running shoes, bedding, vibration suppression affecting a precision instrument or acoustic device, packing material, etc.). Furthermore, since the electrolyte gel obtained by the production method of the present invention has strength, elasticity, flexibility, stretchability, and stretchability, it is an optical material, electrical and electronic material, building material, pharmaceutical / medical material, antistatic agent, light It can be widely used in various industries such as leak-proof films and pressure-sensitive adhesives for optical members.

This application claims the benefit of priority based on Japanese Patent Application No. 2012-214499 filed on September 27, 2012. The entire contents of Japanese Patent Application No. 2012-214499 filed on September 27, 2012 are incorporated herein by reference.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. Of course, it is possible to implement them, and they are all included in the technical scope of the present invention. In the following, “part” means “part by mass” and “%” means “mass%” unless otherwise specified.

In addition, the measurement conditions and test conditions in the following experiments are as shown below.

NMR measurement ¹ H NMR measurement was performed using an NMR apparatus (BRUKER AVANCE 500 type digital, manufactured by BRUKER). The synthesized gelling agent was dissolved in deuterated dimethyl sulfoxide at a concentration of 20 mM, and the measurement was performed at a resonance frequency of 500 MHz.

Gelation test Gelation of the electrolyte gel was determined by the test tube inversion method. Specifically, 0.5 mL of a mixture of the gelling agent obtained in Examples 1 to 4 and Comparative Examples 1 to 8 and the ionic liquid shown in Table 1 was placed in a test tube with a lid having a diameter of 8 mm and a height of 15 mm. And dissolved while shaking at 130 ° C. for 1 minute. This was allowed to stand at room temperature (25 ° C.) for 1 to 24 hours, and then turned upside down to determine gelation. The concentration of the gelling agent was 2% with respect to 100% of the total amount of the mixture of the gelling agent and the ionic liquid. When upside down, the reaction solution does not flow at all when gelled (G), when part of the reaction solution flows, and when some does not flow, partially gelates (PG), viscous behavior , The case where all of the reaction liquid flowed was designated as sol (Sol), and the case where all of the reaction liquid flowed without exhibiting viscous behavior was designated as solution (S). Further, the case where the gelling agent was deposited after standing was agglomerated (P), and the case where the gelling agent was not dissolved in the ionic liquid even when shaken at 130 ° C. for 10 minutes was defined as insoluble (I).
Furthermore, with respect to the gelling agent in which gelation was observed, the gelling test was further performed at a concentration lower than 2%.

Field Emission Scanning Electron Microscope Observation The electrolyte gel obtained by the production method of the present invention was immersed in pure water for several days to replace the ionic liquid in the three-dimensional network structure with pure water and freeze-dried. The xerogel obtained by freeze-drying was coated with palladium, and the three-dimensional network structure was observed with a field emission scanning electron microscope (FE-SEM, JSM-7500F, manufactured by JEOL Ltd.). The acceleration voltage was 5 kV and the observation magnification was 2,000 times.

Conductivity measurement A mixed solution of an ionic liquid and a gelling agent was placed in a U-shaped sample tube, and an electrode was inserted. The U-shaped sample tube was allowed to stand in a 25 ° C. water bath, and after an hour or more had elapsed, impedance measurement was performed using an AC four-terminal method with an input resistance of 2 MΩ, an input capacitance of 20 pF, and CMRR of 50 d or more. For the measurement, a chemical impedance meter 3532-80 (manufactured by Hioki Electric Co., Ltd.) was used.

The measured impedance (Z, θ) was Cole-Cole plotted, the resistance R was calculated from the intersection with the X axis by extrapolating the straight line portion. By using the standard value of JIS K0130-1995 (conductivity k ₀ of 7.437 g / L potassium chloride aqueous solution at 25 ° C. is 12.86 mS / cm) and substituting resistance R into the following formula (2) The cell constant K of the sample tube was determined. And the electrical conductivity of electrolyte gel was calculated | required by Formula (3).
Cell constant (K) = sample tube resistance (R ₀ ) × conductivity (k ₀ ) (2)
Electrolyte gel conductivity (k) = cell constant (K) × electrolyte gel resistance (R) (3)

Example 1
L-alanine methyl ester hydrochloride (16.5 mmol) was dispersed in 200 mL of anhydrous dichloromethane, cooled to 0 ° C., and 4.5 mL of triethylamine was added. A solution of trimesoyl chloride (5.5 mmol) dissolved in 15 mL of anhydrous dichloromethane was added dropwise. It returned to normal temperature (25 degreeC), and stirred for 18 hours.

This was washed twice with 100 mL of 10 mM aqueous hydrochloric acid and with 100 mL each of pure water, and the organic layer was concentrated with an evaporator to obtain a white solid gelling agent. The resulting white solid was subjected to a gelation test. The results are shown in Table 1. The results of NMR measurement were as follows.
¹ H-NMR, (DMSO-d ₆ , 500 MHz) δ 9.14 (d, 1H), 8.50 (s, 1H), 4.52 (m, 1H), 3.66 (s, 3H), 1 .43 (d, 1H)
The results of elemental analysis were as follows.
Calcd. for C ₂₁ H ₂₇ O ₉ N ₃ : C, 54.19; H, 5.85; N, 9.03. Found: C, 52.38; H, 5.36; N, 8.42.

Example 2
A white solid gelling agent was prepared in the same manner as in Example 1, except that L-valine methyl ester hydrochloride (16.5 mmol) was used instead of L-alanine methyl ester hydrochloride (16.5 mmol). Got. The resulting white solid was subjected to a gelation test. The results are shown in Table 1. The results of NMR measurement were as follows.
¹ H-NMR, (DMSO-d ₆ , 500 MHz) δ 8.98 (d, 1H), 8.43 (s, 1H), 4.33 (t, 1H), 3.67 (s, 3H), 2 .20 (m, 1H), 1.01 (d, 3H), 0.96 (d, 3H)
The results of elemental analysis were as follows.
Calcd. _{_{_{for C 27 H 39 O 9 N}}} 3: C, 59.00; H, 7.15; N, 7.65. Found: C, 58.59; H, 6.84; N, 7.62.

Example 3
A white solid gelling agent was prepared in the same manner as in Example 1, except that L-leucine methyl ester hydrochloride (16.5 mmol) was used instead of L-alanine methyl ester hydrochloride (16.5 mmol). Got. The resulting white solid was subjected to a gelation test. The results are shown in Table 1. The results of NMR measurement were as follows.
¹ H-NMR, (DMSO-d ₆ , 500 MHz) δ 9.10 (d, 1H), 8.49 (s, 1H), 4.54 (m, 1H), 3.66 (s, 1H), 1 .81 (m, 1H), 1.72 (m, 1H), 1.59 (m, 1H), 0.94 (d, 3H), 0.90 (d, 3H)
The results of elemental analysis were as follows.
Calcd. _{_{_{for C 30 H 45 O 9 N}}} 3: C, 60.90; H, 7.67; N, 7.10. Found: C, 60.84; H, 7.41; N, 7.08.

Example 4
A white solid gelling agent was prepared in the same manner as in Example 1 except that L-methionine methyl ester hydrochloride (16.5 mmol) was used instead of L-alanine methyl ester hydrochloride (16.5 mmol). Got. The resulting white solid was subjected to a gelation test. The results are shown in Table 1. The results of NMR measurement were as follows.
¹ H-NMR, (DMSO-d ₆ , 500 MHz) δ 9.16 (d, 1H), 8.51 (s, 1H), 4.63 (m, 1H), 3.67 (s, 3H), 2 .58 (m, 2H), 2.07 (m, 5H)
The results of elemental analysis were as follows.
Calcd. _{_{_{for C 27 H 39 O 9 N}}} 3 S 3: C, 50.21; H, 6.09; N, 6.51. Found: C, 50.17; H, 5.79; N, 6.47.

Comparative Example 1
A white solid was obtained in the same manner as in Example 1 except that L-glycine methyl ester hydrochloride (16.5 mmol) was used instead of L-alanine methyl ester hydrochloride (16.5 mmol). The resulting white solid was subjected to a gelation test. The results are shown in Table 1. The results of NMR measurement were as follows.
¹ H-NMR, (DMSO-d ₆ , 500 MHz) δ 9.26 (m, 1H), 8.51 (t, 1H), 4.06 (m, 2H), 3.67 (t, 3H)
The results of mass spectrometry were as follows.
Calcd. for C ₁₈ H ₂₁ O ₉ N ₃ ([M + Na +]) 446.7, found 446.0

Comparative Example 2
A white solid was obtained in the same manner as in Example 1 except that L-phenylalanine methyl ester hydrochloride (16.5 mmol) was used instead of L-alanine methyl ester hydrochloride (16.5 mmol). The resulting white solid was subjected to a gelation test. The results are shown in Table 1. The results of NMR measurement were as follows.
¹ H-NMR, (DMSO-d ₆ , 500 MHz) δ 9.18 (m, 1H), 8.36 (t, 1H), 7.28 (m, 5H), 4.70 (m, 1H), 3 .64 (m, 3H), 3.33 (t, 1H), 3.15 (m, 1H)
The results of elemental analysis were as follows.
Calcd. _{_{_{for C 39 H 39 O 9 N}}} 3: C, 66.4; H, 5.10; N, 6.45. Found: C, 67.2; 4.91; N, 6.19.
The results of mass spectrometry were as follows.
Calcd. for C ₃₉ H ₃₉ O ₉ N ₃ ([M + Na +]) 716.7, found 4715.2

Comparative Example 3
The white solid (2.14 mmol) obtained in Comparative Example 1 was dissolved in 30 mL of methanol and cooled to 0 ° C. After adding 2M NaOH aqueous solution, it returned to normal temperature and hydrolyzed by stirring for 22 hours. The precipitated white solid was collected by filtration, and the residue was dissolved in pure water. The pH was adjusted to 3 or less by adding 1M hydrochloric acid. After standing still for several hours, the supernatant was removed by centrifugation to obtain a white solid. The resulting white solid was subjected to a gelation test. The results are shown in Table 1. The results of NMR measurement were as follows.
¹ H-NMR, (DMSO-d ₆ , 500 MHz) δ 9.26 (m, 1H), 8.51 (st, 1H), 4.06 (m, 2H), 3.67 (t, 3H)
Moreover, the result of mass spectrometry was as follows.
Calcd. for C ₁₅ H ₁₅ O ₉ N ₃ ([M + Na +]) 404.3, found 404.0

Comparative Example 4
The white solid (2.98 mmol) obtained in Example 2 was dissolved in 200 mL of tetrahydrofuran and 2 mL of pure water, added with 35 mL of 2M NaOH aqueous solution, and hydrolyzed by stirring at room temperature for 30 hours. The pH was adjusted to be in the range of 5-6 by adding 2M hydrochloric acid. The solvent was distilled off under reduced pressure using an evaporator. The obtained white solid was dissolved in 2M NaOH aqueous solution. 1M hydrochloric acid was added to adjust the pH to 4-5. The precipitated white solid was collected with a funnel and dried under vacuum to obtain a white solid. The resulting white solid was subjected to a gelation test. The results are shown in Table 1. The results of NMR measurement were as follows.
¹ H-NMR, (DMSO-d ₆ , 500 MHz) δ 12.7 (s, 1H), 8.78 (d, 1H), 8.40 (s, 1H), 4.32 (t, 3H), 2 .21 (m, 1H), 0.99 (t, 6H)

Comparative Example 5
The white solid (2.80 mmol) obtained in Example 4 was dissolved in 100 mL of 1,4-dioxane and 1 mL of pure water, added with 25 mL of 2M NaOH aqueous solution, and hydrolyzed by stirring at room temperature for 30 hours. The pH was adjusted to 5-6 by adding 2M hydrochloric acid, and the solvent was distilled off under reduced pressure with an evaporator. The obtained white solid was dissolved in 2M NaOH aqueous solution. 1M hydrochloric acid was added to adjust the pH to 4-5. The precipitated white solid was collected with a funnel and dried under vacuum to obtain a white solid. The resulting white solid was subjected to a gelation test. The results are shown in Table 1. The results of NMR measurement were as follows.
¹ H-NMR, (DMSO-d ₆ , 500 MHz) δ 12.8 (s, 1H), 9.00 (d, 1H), 8.48 (s, 1H), 4.56 (m, 1H), 2 .57 (m, 2H), 2.07 (m, 5H)

Comparative Example 6
The white solid obtained in Comparative Example 2 was dissolved in 100 mL of methanol and cooled to 0 ° C. 30 mL of 2M NaOH aqueous solution was added, it returned to normal temperature, and it hydrolyzed by stirring for 22 hours. 100 mL of pure water was added to the reaction solution, and the pH was adjusted to 3 or less by adding 1 M hydrochloric acid. After standing still for several hours, the supernatant was removed by centrifugation to obtain a white solid. The resulting white solid was subjected to a gelation test. The results are shown in Table 1. The results of NMR measurement were as follows.
¹ H-NMR, (DMSO-d ₆ , 500 MHz) δ 12.8 (s, 1H), 8.98 (m, 1H), 8.31 (m, 1H), 7.29 (m, 5H), 4 .65 (m, 1H), 3.20 (m, 1H), 3.08 (m, 1H)

Comparative Example 7
0.76 mmol (0.5 g) of the white solid obtained in Comparative Example 4, 0.76 mmol (87.5 mg) of N-hydroxysuccinimide (NHS), 1-ethyl-3- (3-dimethylaminopropyl) ) 0.76 mmol (146 mg) of carbodiimide hydrochloride (WSC), 0.80 mmol (166 mg) of NH ₂ — (CH ₂ CH ₂ O) ₄ —CH _3, 0.76 mmol (76.9 mg) of triethylamine, and dimethyl It was dissolved in 3 mL of formamide and stirred at room temperature (25 ° C.) for 20 hours. The solvent was distilled off using an evaporator. 4 mL of methanol was added to the obtained reaction solution, heated to 60 ° C. to obtain a uniform solution, and then 30 mL of pure water was added. After centrifuging and removing the supernatant, methanol was added again, followed by heating, adding pure water and centrifuging. The resulting yellow precipitate was lyophilized. The resulting yellow solid was subjected to a gelation test. The results are shown in Table 1.
NH ₂ — (CH ₂ CH ₂ O) ₄ —CH ₃ was synthesized by the method described in International Publication No. 2009/109035.

Comparative Example 8
In Comparative Example 8, a yellow solid was obtained in the same manner as Comparative Example 9 except that the white solid obtained in Comparative Example 6 was used instead of the white solid obtained in Comparative Example 4. The resulting yellow solid was subjected to a gelation test. The results are shown in Table 1.

In Table 1, [emim] [TFSA] represents 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) amide, and [bmim] [TFSA] represents 1-butyl-3-methylimidazolium bis (trifluoro). Methylsulfonyl) amide, [hmim] [TFSA] is 1-hexyl-3-methylimidazolium bis (trifluoromethylsulfonyl) amide, and [bpy] [TFSA] is 1-butylpyridinium bis (trifluoromethylsulfonyl). Amide, [emim] [CF ₃ SO ₃ ] is 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, and [bmim] [CF ₃ SO ₃ ] is 1-butyl-3-methylimidazolium trifluoromethanesulfonate. Represent each.

In Table 1, the gelling agents of Examples 1 to 4 are gelling agents that satisfy the requirements defined in the present invention, and are ionic liquids [emim] [TFSA], [bmim] [TFSA], [hmim] [TFSA]. ], [Bpy] [TFSA], [emim] [CF ₃ SO ₃ ] and [bmim] [CF ₃ SO ₃ ], and at the same time showed excellent gelling ability. In particular, the gelling agents of Examples 2 to 4 in which the carbon number of the alkyl group of R ¹ to R ³ in the general formula (1) is 3 or 4 dissolves in almost all ionic liquids and has excellent gelling ability. showed that.

On the other hand, in the compounds of Comparative Examples 1 to 8, the terminal groups of the compounds are carboxyl groups or polyethers. As a result, it was difficult to make a uniform solution by dissolving in an ionic liquid, and even if it was able to be dissolved, it was confirmed that a gelling ability was not exhibited or a gelling agent was reprecipitated.

When Examples 1 to 4 and Comparative Examples 1 to 8 are compared, the gelling agent of the present invention makes it easy to dissolve the gelling agent in the ionic liquid and at the same time gel the ionic liquid. Can be said to be easy.

Table 2 shows the minimum gelling agent concentration at which the ionic liquid could be gelled in the gelling agents of Examples 1 to 4.

In Table 2, [emim] [TFSA], [bmim] [TFSA], [hmim] [TFSA], [bpy] [TFSA], [emim] [CF ₃ SO ₃ ] and [bmim] [CF ₃ SO ₃ ] Represents the same meaning as described above.

Further, as shown in the results shown in Table 2, the gelling agent of the present invention was able to gel the ionic liquid even when the content was as small as 2% by mass or less. If the concentration of the gelling agent is low, an electrolyte gel can be obtained without impairing the excellent electrical conductivity of the ionic liquid.

Example 5
The electrolyte gel obtained in Example 2 was subjected to conductivity measurement. The results are shown in Table 3.

In Table 3, [emim] [TFSA], [bmim] [TFSA], [hmim] [TFSA], and [bmim] [CF ₃ SO ₃ ] have the same meaning as described above. The specific electric conductivity indicates a ratio when the electric conductivity of an ionic liquid without a gelling agent is 100%.

As shown in Table 3, the rate of decrease in electrical conductivity in the case of an electrolyte gel produced by adding the gelling agent of the present invention to an ionic liquid is 0.1% to 5% compared to the original ionic liquid. The electric conductivity was almost the same as that of the original ionic liquid. Therefore, the gelling agent of the present invention can be suitably used for the preparation of electrolytes such as fuel cells, secondary electrons, and dye-sensitized type batteries that require high electrical conductivity.

Example 6
Of the electrolyte gel obtained in Example 2, an electrolyte gel using [bmim] [TFSA] and [bmim] [CF ₃ SO ₃ ] as the ionic liquid was analyzed using a field emission scanning electron microscope (FE-SEM). The results of the observation are shown in FIGS.

Since the gelling agent obtained in Example 2 is insoluble in water, it is not dissolved by solvent replacement with pure water performed in the sample preparation process of FE-SEM observation. Freeze-drying is a drying method that allows drying without destroying the fine structure. Therefore, it can be said that the three-dimensional network structure of FIGS. 1 and 2 is the same as the three-dimensional network structure formed by the gelling agent in the ionic liquid. FIGS. 1 and 2 show that the gelling agent of the present invention forms a fiber-like three-dimensional network structure by self-organization in an ionic liquid. It can be said that it has the ability.

The gelling agent of the ionic liquid of the present invention can form a stable gel while maintaining various characteristics of the ionic liquid, such as high heat resistance and flame retardancy. For this reason, the gelling agent of the present invention and the electrolyte gel obtained by the production method of the present invention are electrolytes for fuel cells, secondary batteries, dye-sensitized solar cells, artificial actuators, electrochemical sensors, light-emitting display devices, impacts It can be used for an absorbent material (for example, running shoes, bedding, vibration suppression affecting a precision instrument or an acoustic device, a packing material, etc.) and a lubricating liquid. Furthermore, since the electrolyte gel obtained by the production method of the present invention has strength, elasticity, flexibility, stretchability, and stretchability, it is an optical material, electrical and electronic material, building material, pharmaceutical / medical material, antistatic agent, light It can be widely used in various industries such as leak-proof films and pressure-sensitive adhesives for optical members.

Claims

General formula (1)

[In Formula (1),
R 1 to R 3 are the same or different and each represents a linear or branched alkyl group having 1 to 9 carbon atoms. However, the methylene group (—CH 2 —) contained in the linear or branched alkyl group of R 1 to R 3 may be replaced with a sulfide bond (—S—).
R 4 to R 6 are the same or different and each represents a linear or branched alkyl group having 1 to 4 carbon atoms]
An ionic liquid gelling agent comprising the compound represented by the formula:
2. The R 1 to R 3 are the same or different and each is one group selected from the group consisting of a methyl group, a 2-propyl group, a 2-methylpropyl group, a 1-methylpropyl group, and a methylthioethyl group. The gelling agent of the ionic liquid as described in 1.
3. The ionic liquid gelling agent according to claim 1, wherein R 4 to R 6 are methyl groups.
A method for producing an electrolyte gel comprising a step of mixing the gelling agent according to any one of claims 1 to 3 and an ionic liquid.
The method for producing an electrolyte gel according to claim 4, further comprising a step of heating and cooling the mixture of the gelling agent and the ionic liquid.
An electrolyte gel comprising the ionic liquid gelling agent according to any one of claims 1 to 3 and an ionic liquid, wherein the ionic liquid is gelled by the gelling agent.
An organic cation selected from the group consisting of an imidazolium ion, a pyridinium ion, a piperidinium ion, a pyrrolidinium ion, a phosphonium ion, an ammonium ion and a sulfonium ion, a halogen ion, a carboxylate ion, a sulfate ion, a sulfonate ion, Selected from the group consisting of thiocyanate ion, nitrate ion, aluminate ion, borate ion, phosphate ion, amide ion, antimonate ion, imide ion, methide ion, amino acid ion, N-acyl acidic amino acid ion and N-acyl neutral amino acid ion The electrolyte gel according to claim 6, comprising an organic anion.
The ionic liquid is 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) amide, 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) amide, 1-hexyl-3-methylimidazolium bis (Trifluoromethylsulfonyl) amide, 1-butylpyridinium bis (trifluoromethylsulfonyl) amide, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate and 1-butyl-3-methylimidazolium trifluoromethanesulfonate The electrolyte gel according to claim 7, which is an ionic liquid selected.
Furthermore, inorganic sulfate, inorganic phosphate, hydroxylated inorganic salt, hexafluorophosphate inorganic salt, trifluorosulfonic acid inorganic salt, perchloric acid inorganic salt, tetrafluoroborate inorganic salt, bis (fluorosulfonyl) imide inorganic salt, The electrolyte gel according to claim 7 or 8, which contains one or two salts selected from the group consisting of bis (trifluoromethylsulfonyl) amide inorganic salts and inorganic cobaltates.
General formula (1)

[In Formula (1),
R 1 to R 3 are the same or different and each represents a linear or branched alkyl group having 1 to 9 carbon atoms. However, the methylene group (—CH 2 —) contained in the linear or branched alkyl group of R 1 to R 3 may be replaced with a sulfide bond (—S—).
R 4 to R 6 are the same or different and each represents a linear or branched alkyl group having 1 to 4 carbon atoms]
A compound represented by
R 1 to R 3 are the same or different and each is one group selected from the group consisting of a methyl group, a 2-propyl group, a 2-methylpropyl group, a 1-methylpropyl group, and a methylthioethyl group. Compound described in 1.
The compound according to claim 10 or 11, wherein R 4 to R 6 are methyl groups.