JP2016134406A - Carboxylic acid compound useful as solute for electrolyte for power storage device and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrolyte for a power storage device, specifically for an electrolytic capacitor, high in withstand voltage, excellent in solubility, and high in safety and reliability.SOLUTION: There is provided a tetracarboxylic acid for a power storage device electrolyte represented by the following general formula (1). (In the formula, R, R, R, R, R, R, Rand Reach represent a hydrogen atom or a 1-4C alkyl group and may be the same as or different from each other, and n represents a number of a methylene group and is an integer of 2-14.)SELECTED DRAWING: None

Description

  The present invention relates to an electrolytic solution for an electricity storage device using tetracarboxylic acid or a salt thereof.

  Conventionally, an electrolytic solution for an electricity storage device, in particular, an electrolytic solution for driving an electrolytic capacitor for medium- and high-voltages, which has a relatively high withstand voltage. Therefore, an electrolytic solution in which ethylene glycol is dissolved in a solvent and boric acid or ammonium borate is dissolved as an electrolyte. Liquid has been used. However, such an electrolytic solution has low conductivity, and a large amount of water is generated by esterification of ethylene glycol and boric acid, so that the moisture reacts with the aluminum oxide film as an electrode to deteriorate the electrode. was there. Further, when the temperature is raised to 100 ° C. or higher, the internal pressure increases due to the evaporation of water, so that there is a problem that it is not suitable for use in a high temperature environment.

  Therefore, in order to solve such problems, in recent years, as electrolytes, for example, dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, 1,10-decanedicarboxylic acid, 1,6-decanedicarboxylic acid, 1 , 3,6-hexanetricarboxylic acid, 1,3-dimethyl-1,3,9-nonanetricarboxylic acid such as tricarboxylic acid and / or electrolytes using these salts have been reported (for example, patent documents) 1, see Patent Document 2).

  However, for example, ammonium salts of dicarboxylic acids such as sebacic acid, dodecanedioic acid, and butyloctanedioic acid described in Patent Document 1 have low solubility in an electrolyte solvent such as ethylene glycol. There was a problem that crystals were likely to precipitate and were not suitable for use. Further, the tricarboxylic acid such as 1,3,6-hexanetricarboxylic acid or a salt thereof described in Patent Document 2 is not sufficiently satisfactory in withstand voltage, and is repaired when the aluminum oxide film is damaged. The chemical conversion is not sufficient, and there is a drawback in that the safety and reliability of the aluminum electrolytic capacitor are lowered. Therefore, in order to improve the safety and reliability of the aluminum electrolytic capacitor, it is desired to further improve the withstand voltage, solubility and chemical conversion property of the electrolytic solution for the electrolytic capacitor.

JP 60-85509 A Japanese Patent No. 4279087

J. et al. Org. Chem. , 30, 1357 (1965) J. et al. Org. Chem. , 30, 1351 (1965)

  An object of the present invention is to provide an electrolytic solution for an electricity storage device, particularly an electrolytic capacitor, which has a high withstand voltage and excellent solubility and safety and high reliability.

  As a result of diligent studies to solve the above problems, it has been found that the problem can be solved by the electrolytic solution for an electricity storage device containing tetracarboxylic acid or a salt thereof described in [1] to [8] below.

[1] A tetracarboxylic acid for an electricity storage device electrolyte represented by the following general formula (1).

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and are the same or different from each other. (N represents the number of methylene groups and is an integer of 2 to 14.)

[2] An electrolytic solution for an electricity storage device comprising the tetracarboxylic acid or a salt thereof according to [1].

[3] A novel tetracarboxylic acid represented by the following general formula (1ak).

^{(Wherein, R 4ak} and ^{R 8Ak} represents an alkyl group having 1 to 4 carbon atoms, respectively may be the same or ^{different, R 1, R 2, R} 3, R 5, R 6, R 7 and n is as defined above.)

[4] A novel tetracarboxylic acid ester represented by the following general formula (2ak).

^{(Wherein, R 9, R 10, R} 11 and ^{R 12} represents an alkyl group having 1 to 4 carbon atoms, which may be identical or different from each ^{other, R 1, R 2, R} 3, R 4ak, R ⁵ , R ⁶ , R ⁷ , R ^8ak and n are as ^defined above.)

[5] By hydrolyzing a novel tetracarboxylic acid ester represented by the following general formula (2ak)

(Wherein R ¹ , R ² , R ³ , R ^4ak , R ⁵ , R ⁶ , R ⁷ , R ^8ak , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² and n are as defined above).
The manufacturing method of the novel tetracarboxylic acid represented by the following general formula (1ak).

(In the formula, R ¹ , R ² , R ³ , R ^4ak , R ⁵ , R ⁶ , R ⁷ , R ^8ak and n are as ^defined above.)
[6] A tricarboxylic acid ester represented by the following general formula (3):

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁹ , R ¹⁰ , R ¹¹ and n are as defined above.)
By reacting an unsaturated ester represented by the following general formula (4)

(Wherein R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ¹² are as defined above.)
The manufacturing method of the tetracarboxylic acid ester represented by following General formula (2).

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² and n are as defined above).
[7] A ketoester represented by the following general formula (5)

(Wherein R ⁹ represents an alkyl group having 1 to 4 carbon atoms, and n is as defined above.)
An unsaturated ester represented by the following general formula (4 ′);

(Wherein R ¹ , R ² , R ³ , R ⁴ and R ¹¹ are as defined above.)
A method for producing a tetracarboxylic acid ester represented by the following general formula (2 ′) by reacting an alcohol R ¹⁰ OH (R ¹⁰ is as defined above) in the presence of a catalyst.

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁹ , R ¹⁰ , R ¹¹ and n are as defined above.)
[8] A diester represented by the following general formula (6):

(In the formula, R ⁹ , R ¹⁰ and n are as defined above.)
Unsaturated ester represented by the following general formula (4 ′)

(Wherein R ¹ , R ² , R ³ , R ⁴ and R ¹¹ are as defined above.)
And a method for producing a tetracarboxylic acid ester represented by the following general formula (2 ′).

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁹ , R ¹⁰ , R ¹¹ and n are as defined above.)

  The tetracarboxylic acid or a salt thereof of the present invention is excellent in low-temperature solubility and voltage resistance, and is suitably used as an electrolyte for an electricity storage device electrolyte, particularly an electrolytic capacitor electrolyte.

<Tetracarboxylic acid of the present invention>
The tetracarboxylic acid of the present invention represents a tetracarboxylic acid represented by the following general formula (1).

In general formula (1), in the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are a hydrogen atom or an alkyl group having 1 to 4 carbon atoms (methyl group, An ethyl group, a propyl group, a butyl group and structural isomers thereof), which may be the same or different from each other. n represents the number of methylene groups and is an integer of 2 to 14.

In the tetracarboxylic acid represented by the general formula (1), the substituents R ¹ , R ² , R ⁵ and R ⁶ are preferably hydrogen atoms, more preferably R ¹ , R ² , R ³ , R ⁵ , R ⁶ and R ⁷ are hydrogen atoms, R ⁴ and R ⁸ are hydrogen atoms or alkyl groups having 1 to 4 carbon atoms, and more preferably substituents R ¹ , R ² , R ³ , R ⁵ , R ^6. And R ⁷ is a hydrogen atom, and R ⁴ and R ⁸ are a hydrogen atom or a methyl group.

  In the tetracarboxylic acid represented by the general formula (1), n is preferably an integer of 2 to 9, and 2, 3, or 9 is particularly preferable.

<Method for producing tetracarboxylic acid>
As methods for producing tetraesters, methods described in Non-Patent Document 1 and Non-Patent Document 2 are known. Tetraester is a method of hydrolyzing and esterifying tetranitrile produced by electroreduction dimerization of α-methyleneglutaronitrile, and reacting 1,1,4,4-tetrabutanoic acid tetraester with acrylonitrile in the presence of a base. 1,4-bis (2-cyanoethyl) -1,1,4,4-tetrabutanoic acid tetraester, which is synthesized by hydrolysis, decarboxylation, esterification, etc., but the reaction is complicated It is not a good method.

  On the other hand, the tetracarboxylic acid represented by the general formula (1) of the present invention can be produced by hydrolyzing the tetracarboxylic acid ester represented by the general formula (2) including the general formula (2ak). I can do it.

  Hydrolysis can be carried out with an aqueous solvent in the presence or absence of a base or acid.

  Examples of the tetracarboxylic acid ester represented by the general formula (2) include octane-1,3,6,8-tetracarboxylic acid, decane-2,4,7,9-tetracarboxylic acid, and nonane-1, 3,7,9-tetracarboxylic acid, undecane-2,4,8,10-tetracarboxylic acid, pentadecane-1,3,13,15-tetracarboxylic acid, heptadecane-2,4,14,16-tetracarboxylic acid Examples thereof include alkyl esters such as acids. The alkyl group of the alkyl ester is an alkyl group having 1 to 4 carbon atoms (including methyl group, ethyl group, propyl group, butyl group and structural isomers thereof), preferably methyl group, ethyl group, particularly A methyl group is preferred.

  Examples of the tetracarboxylic acid represented by the general formula (1) include octane-1,3,6,8-tetracarboxylic acid, decane-2,4,7,9-tetracarboxylic acid, and nonane-1,3. 7,9-tetracarboxylic acid, undecane-2,4,8,10-tetracarboxylic acid, pentadecane-1,3,13,15-tetracarboxylic acid, heptadecane-2,4,14,16-tetracarboxylic acid, etc. Is mentioned.

  In the hydrolysis reaction, an organic solvent can be used for the purpose of accelerating the reaction. Although it does not limit as an organic solvent, Alcohol, especially methanol are preferable.

  Although the usage-amount of an organic solvent is not specifically limited, It is 0-20g with respect to 1g of tetracarboxylic acid ester represented by General formula (2), Preferably it is 0-10g.

When performing base hydrolysis, the base is not particularly limited, but carbonates such as potassium carbonate, sodium carbonate, cesium carbonate, sodium bicarbonate, potassium bicarbonate; sodium hydroxide, potassium hydroxide, magnesium hydroxide, water Hydroxides such as cesium oxide, calcium hydroxide, and barium hydroxide can be used. Particularly preferred is sodium hydroxide.

  The base concentration in the aqueous solvent is not particularly limited, but is preferably 5 to 60%.

  The amount of the base used is preferably 0.5 to 20 mol, more preferably 3 to 8 mol, relative to the number of moles of the tetracarboxylic acid ester represented by the general formula (2).

  Although reaction temperature is not specifically limited, Preferably it is 0-130 degreeC.

After completion of the reaction, for example, neutralize with sulfuric acid and extract with an organic solvent such as MTBE (methyl tert-butyl ether). The target tetracarboxylic acid is obtained by concentration after dehydration.
When acid hydrolysis is performed, the acid is not particularly limited, but mineral acids such as sulfuric acid and hydrochloric acid are preferable.

<Method for producing tetracarboxylic acid ester>
The tetracarboxylic acid ester is produced by the following three production methods.

(First method)
The manufacturing method of the tetracarboxylic acid ester represented by General formula (2) by making the tricarboxylic acid ester represented by General formula (3) react with the unsaturated ester represented by General formula (4).

  This production method is performed by dissolving the tricarboxylic acid ester represented by the general formula (3) in a solvent-free or organic solvent and adding the unsaturated ester represented by the general formula (4) in the presence of a base. .

Examples of the tricarboxylic acid ester represented by the general formula (3) include hexane-1,3,6-tricarboxylic acid, heptane-1,4,6-tricarboxylic acid, heptane-1,3,7-tricarboxylic acid, octane- Examples include alkyl esters such as 1,5,7-tricarboxylic acid, tridecane-1,3,13-tricarboxylic acid, and tetradecane-1,11,13-tricarboxylic acid. The alkyl group of the alkyl ester is an alkyl group having 1 to 4 carbon atoms (including methyl group, ethyl group, propyl group, butyl group and structural isomers thereof), preferably methyl group and ethyl group. .
A particularly preferred tricarboxylic acid ester is trimethyl hexane-1,3,6-tricarboxylate.

  Examples of the unsaturated ester represented by the general formula (4) include alkyl esters such as acrylic acid, methacrylic acid, crotonic acid, 3,3-dimethylacrylic acid, isocrotonic acid, tiglic acid, and phenylacrylic acid. Is an alkyl ester ester of acrylic acid and methacrylic acid. The alkyl group of the alkyl ester is an alkyl group having 1 to 4 carbon atoms (including methyl group, ethyl group, propyl group, butyl group and structural isomers thereof), preferably methyl group and ethyl group. .

  Although it does not specifically limit as an organic solvent, Preferably it is alcohol, More preferably, it is methanol.

  The usage-amount of an organic solvent is not specifically limited, It is 0-50g with respect to 1g of tricarboxylic acid ester represented by General formula (3), Preferably it is 0-20g.

  Although it does not specifically limit as a base, Although an organic base and an inorganic base are mentioned, Preferably it is a metal alkoxide, More preferably, it is sodium methoxide.

  The usage-amount of a base is 0.005 mol-10 mol with respect to the tricarboxylic acid ester represented by General formula (3), Preferably it is 0.01 mol-5 mol, More preferably, it is 0.1 mol-2. Is a mole.

  The reaction temperature is 0 to 150 ° C, preferably 0 to 110 ° C, more preferably 0 to 100 ° C.

  After completion of the reaction, for example, neutralize with acetic acid and extract with an organic solvent such as toluene. The target tetracarboxylic acid ester is obtained by removing the solvent.

(Second method)
The ketoester represented by the general formula (5), the unsaturated ester represented by the general formula (4 ′), and the alcohol R ¹⁰ OH (R ¹⁰ is as defined above) are reacted in the presence of a catalyst. The manufacturing method of the tetracarboxylic acid ester represented by general formula (2 ') by this.

This production method is performed by mixing a ketoester represented by the general formula (5), an unsaturated ester represented by the general formula (4 ′), and an alcohol R ¹⁰ OH in the presence of a catalyst. This reaction is performed in the absence of a solvent or in an organic solvent.

  Examples of ketoesters represented by the general formula (5) include 2-oxocyclopentanecarboxylic acid, 2-oxocyclohexanecarboxylic acid, 2-oxocycloheptanecarboxylic acid, 2-oxocyclooctanecarboxylic acid, 2-oxocyclohexane. Examples include alkyl esters such as nonanecarboxylic acid, 2-oxocyclodecanecarboxylic acid, 2-oxocycloundecanecarboxylic acid, and 2-oxocyclododecanecarboxylic acid. The alkyl group of the alkyl ester is an alkyl group having 1 to 4 carbon atoms (including methyl group, ethyl group, propyl group, butyl group and structural isomers thereof), preferably methyl group and ethyl group. . A particularly preferred ketoester is methyl 2-oxocyclopentanecarboxylate.

  Examples of the unsaturated ester represented by the general formula (4 ′) include alkyl esters such as acrylic acid, methacrylic acid, crotonic acid, 3,3-dimethylacrylic acid, isocrotonic acid, tiglic acid, and phenylacrylic acid. Preferred are alkyl ester esters of acrylic acid and methacrylic acid. The alkyl group of the alkyl ester is an alkyl group having 1 to 4 carbon atoms (including methyl group, ethyl group, propyl group, butyl group and structural isomers thereof), preferably methyl group and ethyl group. .

The alcohol represented by R ¹⁰ OH is an alkyl alcohol having 1 to 4 carbon atoms (including methanol, ethanol, propanol, butanol and structural isomers thereof), preferably methanol, ethanol, particularly preferably methanol. It is.

The amount of the alcohol represented by R ¹⁰ OH is 0.5 mol to 100 mol per ketoester represented by the general formula (5), preferably 0.8 mol to 50 mol.

As the catalyst, a base is preferable. The base is not particularly limited, an organic base, inorganic bases include, preferably R ^{10 OM} (M represents. A metal cation species) is a metal alkoxide represented by, more preferably with sodium methoxide is there.
The usage-amount of a base is 0.005 mol-10 mol with respect to the ketoester represented by General formula (5), Preferably it is 0.01 mol-5 mol, More preferably, it is 0.1 mol-2 mol. is there.

The organic solvent is not particularly limited, an alcohol preferably R ^{10 OH,} preferably methanol, ethanol, particularly preferably methanol.

  The usage-amount of an organic solvent is not specifically limited, It is 0-200g with respect to 1g of ketoester represented by General formula (5), Preferably it is 0-30g.

  The reaction temperature is 0 to 150 ° C, preferably 0 to 110 ° C, more preferably 0 to 100 ° C.

  After completion of the reaction, for example, neutralize with acetic acid and extract with an organic solvent such as toluene. The target tetracarboxylic acid ester is obtained by removing the solvent.

(Third method)
Method for producing tetracarboxylic acid ester represented by the following general formula (2 ′) by reacting the diester represented by the general formula (6) with the unsaturated ester represented by the following general formula (4 ′) .

  This production method is performed by mixing the diester represented by the general formula (6) and the unsaturated ester represented by the general formula (4 ') in the presence of a catalyst. This reaction is performed in the absence of a solvent or in an organic solvent.

Examples of the diester represented by the general formula (6) include adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,10-decanedicarboxylic acid, 1,11-undecanedicarboxylic acid, 1,12- And dialkyl esters such as dodecanedicarboxylic acid.
The alkyl group of the dialkyl ester is an alkyl group having 1 to 4 carbon atoms (including methyl group, ethyl group, propyl group, butyl group and structural isomers thereof), preferably methyl group and ethyl group. . Particularly preferred diesters are dimethyl adipate and diethyl adipate.

  Examples of the unsaturated ester represented by the general formula (4 ′) include alkyl esters such as acrylic acid, methacrylic acid, crotonic acid, 3,3-dimethylacrylic acid, isocrotonic acid, tiglic acid, and phenylacrylic acid. Preferred are alkyl ester esters of acrylic acid and methacrylic acid. The alkyl group of the alkyl ester is an alkyl group having 1 to 4 carbon atoms (including methyl group, ethyl group, propyl group, butyl group and structural isomers thereof), preferably methyl group and ethyl group. .

  Although it does not specifically limit as an organic solvent, Preferably it is alcohol, Especially preferably, they are methanol and ethanol.

  The usage-amount of an organic solvent is not specifically limited, It is 0-200g with respect to 1g of diester represented by General formula (6), Preferably it is 0-30g.

As the catalyst, a base is preferable. The base is not particularly limited, an organic base, inorganic bases include, preferably R ^{10 OM} (M represents. A metal cation species) is a metal alkoxide represented by, more preferably with sodium methoxide is there.

The usage-amount of a base is 0.005 mol-10 mol with respect to the diester represented by General formula (6), Preferably it is 0.01 mol-5 mol, More preferably, it is 0.1 mol-2 mol. is there.

  The reaction temperature is 0 to 150 ° C, preferably 0 to 110 ° C, more preferably 0 to 100 ° C.

  After completion of the reaction, for example, neutralize with acetic acid and extract with an organic solvent such as toluene. The target tetracarboxylic acid ester is obtained by removing the solvent.

<Electrolytic solution for electricity storage device containing tetracarboxylic acid of the present invention>
The tetracarboxylic acid represented by the general formula (1) or a salt thereof of the present invention is a useful compound as a constituent component of an electric storage device, particularly an electrolytic solution for an electrolytic capacitor.

[Tetracarboxylic acid or its salt and the amount used]
In the electrolytic solution for an electricity storage device containing the tetracarboxylic acid represented by the general formula (1) of the present invention or a salt thereof, the tetracarboxylic acid or the salt used may be used alone or in combination of these plural types. Either may be used. Examples of the salt of the tetracarboxylic acid include ammonium salts (NH ₄ ⁺ ); salts with primary amines such as methylamine, ethylamine, and t-butylamine; dimethylamine, ethylmethylamine, diethylamine, and the like. Salt with secondary amine; salt with tertiary amine such as trimethylamine, diethylmethylamine, ethyldimethylamine, triethylamine; salt with quaternary ammonium such as tetramethylammonium, triethylmethylammonium, tetraethylammonium; Salts with imidazolinium such as 2,3,4-tetramethylimidazolinium, 1,3,4-trimethyl-2-ethylimidazolinium, 1,3-dimethyl-2,4-dimethylimidazolinium; 1,3-dimethylimidazolium, 1,3-diethylimidazolium Salts with imidazolium such as 1,3-dimethyl-1,4,5,6-tetrahydropyridinium, tetrahydropyridinium such as 1,2,3-trimethyl-1,4,5,6-tetrahydropyridinium Salts; salts with dihydropyridinium such as 1,3-dimethyl-1,4-dihydropyridinium or 1,3-dimethyl-1,6-dihydropyridinium; Particularly preferred is an ammonium salt (a salt with ammonia).

  Furthermore, the usage-amount of tetracarboxylic acid or its salt in the electrolyte solution for electrical storage devices of this invention will not be restrict | limited especially if it is the quantity which does not have a bad influence on the performance of the electrolyte solution for electrical storage devices.

[Solvent: Electrolyte for electricity storage devices]
The solvent used in the electrolytic solution for an electricity storage device of the present invention is not particularly limited as long as it can dissolve the tetracarboxylic acid or a salt thereof which is the solute of the present invention, and is used alone or in combination of two or more. be able to.
Examples of the solvent that can be used in the electrolytic solution of the present invention include water; methanol, ethanol, propanol, butanol, ethylene glycol, diethylene glycol, propylene glycol, glycerin, 1,4-butanediol, ethylene glycol monomethyl ether, ethylene Alcohols such as glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, triethylene glycol monobutyl ether; methylal, 1,2-dimethoxyethane, 1-ethoxy-2-methoxyethane, 1,2 -Diethoxyethane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether , Ethers such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether; lactones such as γ-butyrolactone, β-butyrolactone, γ-valerolactone, δ-valerolactone; dimethyl carbonate, diethyl carbonate, Carbonates such as methyl ethyl carbonate, ethylene carbonate, propylene carbonate; amides such as formamide, methylformamide, dimethylformamide, ethylformamide, diethylformamide, methylacetamide, dimethylacetamide, ethylacetamide, diethylacetamide; acetonitrile, propionitrile, 3-methoxypropionitrile, g Nitriles such as rutaronitrile and adiponitrile; sulfooxides such as dimethylsulfoxide; sulfones such as dimethylsulfone, sulfolane, 3-methylsulfolane, and 2,4-dimethylsulfolane; furans such as 2,5-dimethoxytetrahydrofuran; Examples thereof include imidazolidinones such as 3-dimethyl-2-imidazolidinone; pyrrolidones such as N-methylpyrrolidone and polyvinylpyrrolidone.
In addition, these solvents may be used alone or as a mixed solvent in which a plurality of types are mixed. In addition, water, ethylene glycol, or γ-butyrolactone is preferably used as the solvent used in the electrolytic solution for an electricity storage device of the present invention. Furthermore, when water is used in the electrolytic solution for electrolytic capacitors of the present invention, the content of water in the electrolytic solution is not particularly limited, but is preferably 90% by mass or less, particularly preferably 30% by mass or less. .

[Other additives: Electrolytic solution for electricity storage devices]
In addition to the tetracarboxylic acid of the present invention or a salt thereof and the above solvent, various additives can be added to the electrolytic solution for the purpose of reducing leakage current, improving withstand voltage, gas absorption, and the like.

  Here, as additives, for example, phosphoric acid compounds, phosphoric acid ester compounds, nitro compounds, nitrile compounds, boric acid compounds, sulfonic acid compounds, phenols, polyhydric alcohols, polyvinyl alcohol, polyvinyl ether, polyethylene glycol, polypropylene Examples thereof include polymer compounds represented by glycol, polyoxyethylene / polyoxypropylene random copolymer, and block copolymer.

Examples of the phosphoric acid compound and the phosphoric acid ester compound include orthophosphoric acid, pyrophosphoric acid, hypophosphorous acid, hypophosphorous acid, phosphorous acid, diphosphorous acid, pyrophosphorous acid, and isophosphoric acid. , Hypophosphoric acid, butyl phosphate, isobutyl phosphate, octyl phosphate, dodecyl phosphate, etc., and phosphoric acid compounds, and salts of phosphate ester compounds include ammonium salts, aluminum salts, etc. Examples of the nitro compound include nitromethane, nitroethane, nitropropane, nitrobutane, nitrobenzene, nitroanisole, nitroaniline, nitrobenzoic acid, nitrotoluene, nitrophenol, nitrobenzyl alcohol, nitroacetophenone, etc. There is no particular limitation as long as it has a group Acetonitrile, propionitrile, butyronitrile, valeronitrile, hexanenitrile, acrylonitrile, methacrylonitrile, adiponitrile, 1,5-dicyanopentane, 1,6-dicyanohexane, 1,7-dicyanoheptane, 1,8-dicyanooctane, 1,9-dicyanononane, 1,10-dicyanodecane, 1,12-dicyanododecane, 2,4-dimethylglutaronitrile, 1,6-dicyanodecane, propylenedinitrile, 1,3-butadienedinitrile, 1, 2,3-pentatrienedinitrile, 1,2,3,4-heptatetraenedinitrile, 1,2,3,4,5-octapentadenedinitrile, benzonitrile and the like can be mentioned. Examples thereof include boric acid, boric acid ester, and cyclic boric acid.
Furthermore, in the electrolytic solution for an electricity storage device of the present invention, if necessary, in addition to tetracarboxylic acid and / or a salt thereof, other carboxylic acid or carboxyl Acid salts can be added.

  For example, formic acid, acetic acid, propionic acid, pivalic acid, butyric acid, caproic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, lauric acid, stearic acid, benzoic acid, 3,3-dimethylbutane Acids, monocarboxylic acids such as 2,2-diisopropylpropanoic acid, cyanoacetic acid, cyanopropionic acid, 4-cyanobutanoic acid, 5-cyanovaleric acid, 11-cyanoundecanoic acid, 7-cyanoundecanoic acid; maleic acid, phthalic acid , Fumaric acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, 1,7-octane dicarboxylic acid, sebacic acid, 1,10-decanedicarboxylic acid, 2-methyl azelaic acid, 1,6 -Decanedicarboxylic acid, 5,6-decanedicarboxylic acid, 7-vinylhexadecene-1,16-dicarbo Dicarboxylic acids such as acids; tricarboxylic acids such as 1,3,6-hexanetricarboxylic acid and 1,3-dimethyl-1,3,9-nonanetricarboxylic acid, and polycarboxylic acids having a tetracarboxylic acid or higher. It is done. Examples of the carboxylic acid salt include salts of the carboxylic acid.

In the electrolytic solution for an electricity storage device of the present invention, the amount of solvent and the dissolved mass of the electrolytic solution vary depending on the use of the electrolytic capacitor, the rated voltage, and the like, and are not particularly limited. The dissolved mass is preferably 0.5 to 50.0 mass%.

[Electric storage device to which the electrolytic solution of the present invention is applied]
Examples of the electricity storage device to which the electrolytic solution of the present invention is applied include secondary batteries, electric double layer capacitors, lithium ion capacitors, and electrolytic capacitors, with electrolytic capacitors being preferred. The electrolytic capacitor is not particularly limited. For example, it is a scraped aluminum electrolytic capacitor, and a separator is interposed between an anode (aluminum oxide foil) in which aluminum oxide is formed on the anode surface and a cathode aluminum foil. For example, a capacitor formed by winding. The electrolytic capacitor of the present invention is impregnated into the separator as a driving electrolytic solution in this electrolytic capacitor, and after being accommodated together with the positive and negative electrodes in, for example, a bottomed cylindrical aluminum case, the opening of the aluminum case is sealed with a sealing material. Thus, an aluminum electrolytic capacitor can be manufactured.

  Next, an Example is given and this invention is demonstrated concretely. In addition, the material, usage-amount, ratio, operation, etc. which are shown to an Example can be suitably changed unless it deviates from the summary of this invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

(Synthesis of intermediate tetraester)
Example 1 Synthesis of Octane-1,3,6,8-tetracarboxylic acid tetramethyl ester (diastereomer mixture) To 20 g of dimethyl adipate, 22 g of a 28% sodium methoxide solution was added and heated to 40 ° C. 20 g of methyl acrylate was added dropwise, heated to 70 ° C., and reacted for 3.5 hours.

After cooling, the mixture was neutralized with acetic acid and extracted with toluene. After drying over anhydrous sodium sulfate, the solvent was distilled off under reduced pressure to obtain a yellow oil. Distillation under reduced pressure gave colorless oil octane-1,3,6,8-tetracarboxylic acid tetramethyl ester (diastereomer mixture).
Analytical data of the obtained compound is as follows.

MS (EI): m / z = 315 (M ⁺ -31), 282, 255, 223, 160, 128
MS (CI): m / z = 347 (M ⁺ +1), 315
¹ H NMR (CDCl3, δppm): 1.30-2.00 (m, 8H), 2.20-2.50 (m, 6H), 3.65-3.70 (m, 12H)
¹³ C NMR (CDCl3, δppm): 29.55, 29.77, 31.63, 31.66, 44.36, 44.55, 51.67, 173. 32, 175.46, 175.55

Example 2 Synthesis of octane-1,3,6,8-tetracarboxylic acid tetramethyl ester (diastereomer mixture) (from ketoester)
To 2 g of dimethyl adipate, 2.2 g of 28% sodium methoxide solution was added, and the mixture was heated at 70 ° C. and reacted for 2.5 hours. 40% of 2-carbomethoxycyclopentanone was produced. 2.2 g of methyl acrylate was added and stirred with heating.
According to GC analysis, about 80% of octane-1,3,6,8-tetracarboxylic acid tetramethyl ester (a mixture of diastereomers) was formed.

Example 3 Synthesis of decane-2,4,7,9-tetracarboxylic acid tetramethyl ester (mixture of diastereomers) (from diester)
Methyl methacrylate was added to a mixture of 25 g of dimethyl adipate and 2.7 g of sodium methoxide, and reacted at 100 ° C. for 50 hours. After completion of the reaction, the mixture was allowed to cool to room temperature, and 3.0 g of acetic acid was added to neutralize the catalyst. Extracted with MTBE and washed with water. The solvent was removed under reduced pressure. The residue was heated to 100 ° C. or higher under reduced pressure to distill off the light-boiling component, and 39.3 g of a crude tetraester (diastereomer mixture) was obtained as the residue.
Analytical data of the obtained compound is as follows.

Colorless oil
MS (EI): m / z = 343 (M ⁺ -31), 314, 283, 251, 223
MS (CI): m / z = 375 (M ⁺ +1), 343

Example 4 Synthesis of decane-2,4,7,9-tetracarboxylic acid tetramethyl ester (mixture of diastereomers) (from triester)
To 200 mg of trimethyl heptane-1,4,6-tricarboxylate (diastereomer mixture), 158 mg of 28% sodium methoxide and 81 mg of methyl methacrylate were added and reacted at 60 ° C. for 6 hours. After neutralization with acetic acid, toluene was extracted and analyzed by GC. About 80% of decane-2,4,7,9-tetracarboxylic acid tetramethyl ester (a mixture of diastereomers) was formed.

(Synthesis of tetracarboxylic acid)
Example 5 Decane-2,4,7,9-tetracarboxylic acid (diastereomeric mixture)
2.1 g of methanol was added to 39.3 g of decane-2,4,7,9-tetracarboxylic acid tetramethyl ester (diastereomer mixture) obtained in Example 4, and 99.8 g of 5N aqueous sodium hydroxide solution was added. added. The reaction solution was heated and stirred at an internal temperature of 88 ° C. for 5 hours. After the reaction, 15.1 g of methanol was distilled off under reduced pressure. The reaction solution after distillation was neutralized by adding 45 g of 47% sulfuric acid. Extracted with MTBE and washed 5 times with water. The water in the reaction solution was distilled off by Dean Stark. MTBE was concentrated, and the precipitated white crystals were collected by filtration and dried to obtain 18.7 g of decane-2,4,7,9-tetracarboxylic acid (diastereomer mixture).
Analytical data of the obtained compound is as follows.

(Analysis data)
MS (CI): m / z = 319 (M ⁺ +1), 283, 237
¹ H NMR (DMSO-d6, δppm): 1.06 (6H, d, J = 6Hz), 1.36-1.87 (8H, m), 2.23-2.28 (4H, m), 12.15-12.25 (4H, br).
¹³ C NMR (DMSO-d6, δ ppm): ¹³ C NMR (400 MHz, DMSO-d) δ = 16.58, 26.89, 29.92, 36.77, 37.27, 176.48, 177.06.

Example 6 Octane-1,3,6,8-tetracarboxylic acid (diastereomeric mixture)
In the same manner as in Example 6, octane-1,3,6,8-tetracarboxylic acid tetramethyl ester was synthesized by hydrolysis with 5N sodium hydroxide.

¹ H NMR (DMSO-d6, δppm): 1.28-1.78 (m, 8H), 2.10-2.36 (m, 6H), 12.15 (brs. 4H)
¹³ C NMR (DMSO-d6, δppm): 26.73, 29.21, 31.44, 43.91, 173.95, 176.63

(Function evaluation)
Using the obtained tetracarboxylic acid, each component shown in Table 1 below was mixed at a predetermined ratio and adjusted to pH 6 with ammonia to obtain an electrolytic capacitor electrolyte.
The obtained electrolytic capacitor electrolyte solution was measured for withstand voltage when formed with a constant current having a current density of 10 mA / cm ² using an aluminum foil. Furthermore, the solubility of each electrolytic solution at room temperature and −25 ° C. was visually evaluated. These results are also shown in Table 1.

(Comparative Examples 1-3)
Carboxylic acid or carboxylic acid ester shown in the following Table 1 was used as an electrolyte, and each component was mixed at a predetermined ratio and adjusted to pH 6 with ammonia to obtain an electrolytic capacitor electrolyte.
The obtained electrolytic capacitor electrolyte solution has a withstand voltage (V) when formed at a constant current of 10 mA / cm ² using an aluminum foil, and formation ability (withstand voltage (V) / withstand voltage) Time (min) was used as an index). The solubility at room temperature and −25 ° C. of each electrolytic solution was visually evaluated. These results are also shown in Table 1.

* 1: Evaluation of solubility; ○: Dissolved ×: Crystal precipitated

  As is apparent from Table 1 above, it can be seen that the novel electrolyte containing the tetracarboxylic acid of the present invention is superior in withstand voltage, conductivity, solubility, and the like as compared with the electrolyte of the comparative example. It was.

  The novel electrolytic solution containing the tetracarboxylic acid of the present invention is excellent in withstand voltage, electrical conductivity, and solubility, and is particularly suitable for medium- and high-voltage power storage devices, particularly aluminum electrolytic capacitors.

Claims (8)

Tetracarboxylic acid for electrical storage device electrolyte represented by following General formula (1).

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and are the same or different from each other. (N represents the number of methylene groups and is an integer of 2 to 14.) The electrolyte solution for electrical storage devices containing the tetracarboxylic acid or its salt of Claim 1. A novel tetracarboxylic acid represented by the following general formula (1ak).

^{(Wherein, R 4ak} and ^{R 8Ak} represents an alkyl group having 1 to 4 carbon atoms, respectively may be the same or ^{different, R 1, R 2, R} 3, R 5, R 6, R 7 and n is as defined above.) A novel tetracarboxylic acid ester represented by the following general formula (2ak).

^{(Wherein, R 9, R 10, R} 11 and ^{R 12} represents an alkyl group having 1 to 4 carbon atoms, which may be identical or different from each ^{other, R 1, R 2, R} 3, R 4ak, R ⁵ , R ⁶ , R ⁷ , R ^8ak and n are as ^defined above.) By hydrolyzing a novel tetracarboxylic acid ester represented by the following general formula (2ak)

(Wherein R ¹ , R ² , R ³ , R ^4ak , R ⁵ , R ⁶ , R ⁷ , R ^8ak , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² and n are as defined above).
The manufacturing method of the novel tetracarboxylic acid represented by the following general formula (1ak).

(In the formula, R ¹ , R ² , R ³ , R ^4ak , R ⁵ , R ⁶ , R ⁷ , R ^8ak and n are as ^defined above.) Tricarboxylic acid ester represented by the following general formula (3)

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁹ , R ¹⁰ , R ¹¹ and n are as defined above.)
By reacting an unsaturated ester represented by the following general formula (4)

(Wherein R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ¹² are as defined above.)
The manufacturing method of the tetracarboxylic acid ester represented by following General formula (2).

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² and n are as defined above). A ketoester represented by the following general formula (5):

(Wherein R ⁹ represents an alkyl group having 1 to 4 carbon atoms, and n is as defined above.)
An unsaturated ester represented by the following general formula (4 ′);

(Wherein R ¹ , R ² , R ³ , R ⁴ and R ¹¹ are as defined above.)
A method for producing a tetracarboxylic acid ester represented by the following general formula (2 ′) by reacting an alcohol R ¹⁰ OH (R ¹⁰ is as defined above) in the presence of a catalyst.

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁹ , R ¹⁰ , R ¹¹ and n are as defined above.) A diester represented by the following general formula (6):

(In the formula, R ⁹ , R ¹⁰ and n are as defined above.)
Unsaturated ester represented by the following general formula (4 ′)

(Wherein R ¹ , R ² , R ³ , R ⁴ and R ¹¹ are as defined above.)
And a method for producing a tetracarboxylic acid ester represented by the following general formula (2 ′).

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁹ , R ¹⁰ , R ¹¹ and n are as defined above.)