JP4891101B2 - Electrolyte - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrolytic solution containing additive agent which restrains lowering of electric conductivity of the electrolytic solution to express high withstand voltage. <P>SOLUTION: The electrolytic solution comprises at least one of an acid wherein proton partial potential of acid (A1) calculated by an AM1 method of quantum-mechanical calculation soft CAChe is 0.260-0.290 or salt (A2) of the acid (A1). In the electrolytic solution for electrolytic capacitor, (A1) and (A2) contain oxy-alkyline group, and further total concentration in the electrolytic solution of the (A1) and (A2) is 0.001-5%, desirably the acid (A1) is a compound containing a functional group represented by a general formula (1). <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention relates to an electrolytic solution, and more particularly to an electrolytic solution used for an electrolytic capacitor.

In recent years, with the miniaturization, low impedance, and high reliability of capacitors, development of electrolytic solutions for electrolytic capacitors having high withstand voltage and high specific conductivity is expected. Conventionally, an electrolytic solution obtained by adding boric acid to ethylene glycol has been used as the medium-high pressure class electrolytic solution. However, there has been a problem that boric acid is esterified under a high temperature condition and specific conductivity is remarkably lowered. In recent years, typical withstand voltage improvements such as polyoxyethylene, ethers having a polyoxyprepylene chain (for example, Patent Document 1), fatty acid esters (for example, Patent Document 2), phosphate esters (for example, Patent Document 3), etc. The agent is used by adding to the electrolyte.
Japanese Patent Laid-Open No. 3-120812 JP-A-3-120813 JP-A-3-242915

When a withstand voltage improver such as polyoxyethylene, an ether having a polyoxyprepylene chain, a fatty acid ester, or a phosphate ester is used in the electrolytic solution, it is usually several% or more to exhibit the withstand voltage improving effect. A concentration additive is required, which causes a problem that the conductivity of the electrolytic solution is lowered.
The subject of this invention is providing the electrolyte solution containing the additive which suppresses the fall of the electrical conductivity of electrolyte solution and can express a high withstand voltage.

酸（Ａ１）が、下記一般式（２）で示される酸及びそのエステルの少なくとも一方であり、少なくとも１個の一般式(１)で示される官能基を有する酸（Ａ１１）、

[Ｒ _１ は直鎖または分岐を有する飽和の炭素数２〜１０である２価の炭化水素基であり、同じでも異なっていてもよい。−Ｒ _１ Ｏ−の付加様式はランダムでもブロックでもよい。ｎは１〜２２０の自然数である。Ｘは、水素原子、直鎖または分岐を有する飽和の炭素数１〜３００である１価の炭化水素基であり、水酸基、チオール基、アミノ基、カルボキシル基、カルボニル基、エーテル基、チオエーテル基を有する直鎖または分岐を有する飽和の炭素数１〜３００である１価の炭化水素基でもよい。]
下記一般式（３）で示される酸及びそのエステルの少なくとも一方であり、少なくとも１個の一般式(１)で示される官能基を有する酸（Ａ１２）、

[Ｒ _１ 及びｎは一般式（２）と同じである。]、
下記一般式（４）で示される酸及びそのエステルの少なくとも一方であり、少なくとも１個の一般式(１)で示される官能基を有する酸（Ａ１３）、

[Ｒ _１ 、ｎ及びＸは一般式（２）と同じである。Ｒ ₂ は直鎖または分岐を有する飽和の炭素数２〜１０である２価の炭化水素基であり、同じでも異なっていてもよい。−Ｒ ₂ Ｏ−の付加様式はランダムでもブロックでもよい。Ｒ _１ 及びＲ ₂ は互いに同じでも異なっていてもよい。ｍは１〜２２０の自然数である。ｋは１〜８０の自然数である。Ｙは、水素原子、直鎖または分岐を有する飽和の炭素数１〜３００である１価の炭化水素基、であり、水酸基、チオール基、アミノ基、カルボキシル基、カルボニル基、エーテル基、チオエーテル基を有する直鎖または分岐を有する飽和の炭素数１〜３００である１価の炭化水素基でもよい。] 、
下記一般式（５）で示される酸及びそのエステルの少なくとも一方であり、少なくとも１個の一般式(１)で示される官能基を有する酸（Ａ１４）、

[Ｒ _１ 、Ｒ _２、 ｋ、ｍ及びｎは一般式（４）と同じである。] 、
下記一般式（６）で示される酸であり、少なくとも１個の一般式(１)で示される官能基を有する酸（Ａ１５）、及び

[Ｒ _１ 、Ｘ及びｎは一般式（２）と同じである。] 、
下記一般式（７）で示される酸及びそのエステルの少なくとも一方であり、少なくとも１個の一般式(１)で示される官能基を有する酸（Ａ１６）

[Ｒ _１ 、Ｘ及びｎは一般式（２）と同じである。] からなる群より選ばれる少なくとも１種であることを特徴とする電解コンデンサ用電解液、及び該電解液からなる電解コンデンサである。 When using a withstand voltage improver in the electrolyte, it is necessary for the withstand voltage improver to be present in the vicinity of the anodized aluminum film in the vicinity of the anodized aluminum film in order to express the withstand voltage improving effect. When a withstand voltage improver such as an ether having a polyoxypropylene chain is used in the electrolytic solution, it is considered that an additive having a concentration of several percent or more is usually required to exhibit the withstand voltage improving effect.
Therefore, by providing the withstand voltage improver having an oxyalkylene group with an anionic charge, the withstand voltage improver tends to be close to the anodized aluminum coating, so the amount of withstand voltage improver added to the electrolyte is reduced. However, since it is possible to secure the concentration of the withstand voltage improver necessary to express the withstand voltage improvement effect in the vicinity of the anodized aluminum coating, it is possible to suppress the decrease in specific conductivity while maintaining the withstand voltage improvement effect. Thought.
As a measure for imparting an anionic charge to the withstand voltage improver, for example, there is a method of introducing a carboxyl group, a phosphate group, a sulfonic acid group, etc. capable of releasing protons into the withstand voltage improver. The more functional groups that exhibit strong acidity such as sulfone groups are introduced, the easier it is to release protons, and it is thought that they are effective in a small amount, but in fact, the anodized aluminum coating is easily corroded, and the withstand voltage is significantly reduced. There are challenges. Therefore, it was thought that by controlling the ease of proton release, it is possible to design a withstand voltage improver that exhibits a withstand voltage improving effect in a small amount and does not cause corrosion. The ease of proton release can be estimated by the magnitude of the proton partial charge of the acid.
In the present invention, by setting the proton partial charge of the acid calculated by the AM1 method of the quantum mechanics calculation software CAChe to 0.260 to 0.290, corrosion does not occur and the effect of improving the withstand voltage is exhibited in a small amount. An electrolytic solution for a capacitor containing an improver can be provided.
That is, in the present invention, at least one of an acid (A1) and an acid (A1) salt (A2) having a proton partial charge of 0.260 to 0.290 calculated by the AM1 method of the quantum mechanics calculation software CAChe is used. a electrolyte containing, (A1) and (A2) comprises an oxyalkylene group, and Ri total concentration of 0.001% to 5% der in the electrolytic solution of (A1) and (A2),
The acid (A1) is a compound having a functional group represented by the following general formula (1),

The acid (A1) is at least one of an acid represented by the following general formula (2) and an ester thereof, and an acid (A11) having at least one functional group represented by the general formula (1);

[R ₁ is a linear or branched divalent hydrocarbon group having 2 to 10 saturated carbon atoms, and may be the same or different. The addition mode of —R ₁ O— may be random or block. n is a natural number of 1 to 220. X is a hydrogen atom, a straight-chain or branched monovalent hydrocarbon group having 1 to 300 carbon atoms, a hydroxyl group, a thiol group, an amino group, a carboxyl group, a carbonyl group, an ether group, or a thioether group. It may be a straight chain or branched monovalent hydrocarbon group having 1 to 300 carbon atoms. ]
An acid (A12) having at least one of an acid represented by the following general formula (3) and an ester thereof and having at least one functional group represented by the general formula (1);

[R ₁ and n are the same as those in the general formula (2). ],
An acid (A13) having at least one of the acid represented by the following general formula (4) and an ester thereof and having at least one functional group represented by the general formula (1);

[R ₁ , n and X are the same as those in the general formula (2). R ₂ is a straight or branched divalent hydrocarbon group having 2 to 10 saturated carbon atoms, and may be the same or different. -R ₂ O-addition manner may be random or block. R ₁ and R ₂ may be the same or different from each other. m is a natural number of 1 to 220. k is a natural number of 1-80. Y is a hydrogen atom, a linear or branched monovalent hydrocarbon group having 1 to 300 carbon atoms, a hydroxyl group, a thiol group, an amino group, a carboxyl group, a carbonyl group, an ether group, a thioether group It may be a monovalent hydrocarbon group having 1 to 300 saturated carbon atoms having a straight chain or having a branched chain. ]
An acid (A14) having at least one of the acid represented by the following general formula (5) and an ester thereof and having at least one functional group represented by the general formula (1);

[R ₁ , R _2, k, m and n are the same as those in the general formula (4). ]
An acid represented by the following general formula (6), an acid (A15) having at least one functional group represented by the general formula (1), and

[R ₁ , X and n are the same as those in the general formula (2). ]
Acid (A16) having at least one of the acid represented by the following general formula (7) and its ester and having at least one functional group represented by the general formula (1)

[R ₁ , X and n are the same as those in the general formula (2). At least Tanedea for Rukoto electrolytic capacitor characterized by the electrolyte being selected from the group consisting of, and an electrolytic capacitor consisting of the electrolyte solution.

  The electrolytic solution of the present invention exhibits a high withstand voltage improvement effect by the addition of a small amount of withstand voltage improver, and can suppress a decrease in specific conductivity accompanying the addition of the withstand voltage improver.

  The acid (A1), which is a withstand voltage improver contained in the electrolytic solution of the present invention, is released when the proton partial charge of the acid calculated by the AM1 method of the quantum mechanics calculation software CAChe is less than 0.260. It is difficult to achieve the effect of improving the withstand voltage with a small amount. Examples of the compound having a proton partial charge of less than 0.260 include compounds containing carboxylic acid and boric acid. On the other hand, if the proton partial charge of the acid exceeds 0.290, protons are easily released, but the acid corrodes the acid anodized aluminum, so that the withstand voltage is remarkably lowered and cannot be used. Examples of the compound having a proton partial charge exceeding 0.290 include a compound containing a sulfonic acid group and a sulfuric acid group. When the proton partial charge is 0.260 to 0.290, corrosion resistance is not caused, and the effect of improving the withstand voltage can be exhibited by adding a small amount. Examples of the compound having a proton partial charge of 0.260 to 0.290 include a compound containing a phosphate group or a phosphite group.

The partial charges are calculated by the AM1 method of quantum mechanical calculation software CAChe. The AM1 method of the CAChe system can be calculated using, for example, CAChe WORKSYSTEM 5.02 manufactured by Fujitsu Limited. The partial charge can be calculated by drawing a molecular structure to be calculated on WorkSpace and optimizing the structure with AM1 geometry. In structure optimization, semi-empirical parameters are selected based on the initial structure, and the molecular energy and the force applied to the atoms are quantum-calculated. The AM1 method is a kind of semi-empirical molecular orbital method in which an integral necessary for calculation is determined from experimental values, and a partial charge in a vacuum can be obtained.
The above AM1 method is based on the calculation method described in J. Am. Chem. Soc., 107, 3902 (1985) and MOPAC guidebook Kaibundo Publishing Co., Ltd. September 15, 1994, 2nd edition. is there.

The total concentration of the acid (A1) and its salt (A2) in the electrolytic solution is 0.001% to 5%, preferably 0.1% to 2%, and more preferably 0.3 to 1.%. 5%. If it is less than 0.001%, the withstand voltage is not improved, and if it exceeds 5%, the specific conductivity is remarkably lowered.

  It is preferable that the acid (A1) is a compound having a functional group represented by the following general formula (1). Corrosion does not occur with respect to the anodized aluminum coating, and the effect of improving the withstand voltage is exhibited in a small amount, resulting in a decrease in specific conductivity. There is almost no.

Preferable examples of the acid (A1) include the following acids (A11) to (A16). Since the acid (A1) contains a polyoxyalkylene group, it exhibits an excellent withstand voltage improvement effect. Two or more of these acids (A11) to (A16) may be used in combination.
Acid (A11): At least one of an acid represented by the following general formula (2) and an ester thereof, but having at least one functional group represented by the general formula (1).

R ₁ is preferably a linear or branched, saturated or unsaturated divalent hydrocarbon group having 2 to 10 carbon atoms, and has a carbon number of 2 to 2 from the viewpoint of compatibility between specific conductivity and withstand voltage and solubility. 4 is more preferable. The addition mode of —R ₁ O— may be random or block.
n is preferably a natural number of 1 to 220, and more preferably 1 to 20 from the viewpoint of compatibility between specific conductivity and withstand voltage and solubility.
X is a hydrogen atom, a straight-chain or branched, saturated or unsaturated monovalent hydrocarbon group having 1 to 300 carbon atoms, a hydroxyl group, a thiol group, an amino group, a carboxyl group, a carbonyl group, or an ether group. In addition, a straight-chain or branched, saturated or unsaturated monovalent hydrocarbon group having 1 to 300 carbon atoms having a thioether group is preferable. From the viewpoint of compatibility between the specific conductivity and withstand voltage and the solubility, hydrogen A saturated or unsaturated monovalent hydrocarbon group having 1 to 20 carbon atoms and a hydroxyl group having an atom, straight chain or branch is more preferred.
Acid (A12): At least one of an acid represented by the following general formula (3) and an ester thereof, but having at least one functional group represented by the general formula (1).

R ₁ and n are the same as those in the general formula (2).
Acid (A13): At least one of an acid represented by the following general formula (4) and an ester thereof, but having at least one functional group represented by the general formula (1).

R ₁ is the same as in the general formula (2).
R ₂ is preferably a linear or branched, saturated or unsaturated divalent hydrocarbon group having 2 to 10 carbon atoms, and has a carbon number of 2 to 2 from the viewpoint of compatibility between specific conductivity and withstand voltage and solubility. 4 is more preferable. -R ₂ O-addition manner may be random or block.
n is the same as in the general formula (2). m is preferably a natural number of 1 to 220, and more preferably 1 to 20 from the viewpoint of compatibility between specific conductivity and withstand voltage and solubility.
k is preferably a natural number of 1 to 80, and more preferably 1 to 10 from the viewpoint of compatibility between specific conductivity and withstand voltage and solubility.
X is the same as in the general formula (2).
Y is a hydrogen atom, a linear or branched, saturated or unsaturated monovalent hydrocarbon group having 1 to 300 carbon atoms, a hydroxyl group, a thiol group, an amino group, a carboxyl group, a carbonyl group, or an ether group. In addition, a straight-chain or branched, saturated or unsaturated monovalent hydrocarbon group having 1 to 300 carbon atoms having a thioether group is preferable. From the viewpoint of compatibility between the specific conductivity and withstand voltage and the solubility, hydrogen A saturated or unsaturated monovalent hydrocarbon group having 1 to 20 carbon atoms and a hydroxyl group having an atom, straight chain or branch is more preferred.
Acid (A14): At least one of an acid represented by the following general formula (5) and an ester thereof, but having at least one functional group represented by the general formula (1).

R ₁ , R _2, k, m and n are preferably the same as those in the general formula (4).
Acid (A15): An acid represented by the following general formula (6), but having at least one functional group represented by the general formula (1).

R ₁ , X and n are the same as those in the general formula (2).
Acid (A16): At least one of an acid represented by the following general formula (7) and an ester thereof, but having at least one functional group represented by the general formula (1).

R ₁ , X and n are the same as those in the general formula (2).

In the acids (A11) to (A16), R ₁ and R _{2 each} having a group consisting of at least one of an ethylene group and a propylene group are particularly preferable from the viewpoints of compatibility between specific conductivity and withstand voltage and solubility. preferable.

The number average molecular weight of the acid (A1) that is a withstand voltage improver contained in the electrolytic solution of the present invention is preferably 150 to 10,000, more preferably 200 to 4,000, and more preferably 200 to 2000. It is. When the number average molecular weight is 150 or more, there is no possibility of corroding the anodized aluminum film, and when the number average molecular weight is 10,000 or less, it is preferable because it dissolves in the electrolytic solution.
Number average molecular weight: Measured by GPC (gel permeation chromatography). Using a monodisperse polystyrene standard sample, obtain the relationship between the marker count and molecular weight, read the molecular weight Mi and height Hi at each count i from the chart of the measurement sample containing the voltage resistance improver, and calculate the number average from the following formula Determine the molecular weight.
Number average molecular weight (Mn) = ΣHi · Mi / ΣHi

As a specific example of the acid (A1) that is a withstand voltage improver contained in the electrolytic solution of the present invention,
Acid (A11): In the general formula _{(2), (X = H} , n = 8, R 1 = -C 2 H 4 -), (X = C 12 H 25 -, n = 8, R 1 = -C ₂ H ₄ -), such as,
Acid (A12): In the general formula _{(3), (X = H} , n = 8, R 1 = -C 2 H 4 -), (X = C 12 H 25 -, n = 8, R 1 = -C ₂ H ₄ -), _{etc., (n = 8, R 1} = -C 2 H 4 - , _{etc.), -), (n =} 8, R 1 = -C 3 H 6
Acid (A13): In the general formula (4), (X = H, Y = H, m = 8, n = 8, k = 1, R ₁ = —C ₂ H ₄ —, R ₂ = —C ₂ H _{4 -), (X = C} 12 H 25 -, Y = C 12 H 25 -, m = 8, n = 8, k = 1, R 1 = -C 2 H 4 -, R 2 = -C 2 H _4- )
Acid (A14): In the general formula (5), (X = H , Y = H, m = 8, n = 8, k = 1, R 1 = -C 2 H 4 -, R 2 = -C 2 H _{4 -), (X = C} 12 H 25 -, Y = C 12 H 25 -, m = 8, n = 8, k = 1, R 1 = -C 2 H 4 -, R 2 = -C 2 H _4- )
Acid (A15): In the general formula _{(6), (X = H} , n = 8, R 1 = -C 2 H 4 -), (X = C 12 H 25 -, n = 8, R 1 = -C ₂ H ₄ -), such as,
Acid (A16): In the general formula _{(7), (X = H} , n = 8, R 1 = -C 2 H 4 -), (X = C 12 H 25 -, n = 8, R 1 = -C ₂ H ₄ -) and the like.

  Among the acids (A11) to (A16), as the ester of the acid represented by the general formulas (2) to (7), the general formula (8) obtained by a dehydration reaction between a hydroxyl group directly bonded to phosphorus and an alcohol. An alkyl phosphate ester as shown in FIG.

Ｒとしては、直鎖または分岐を有する飽和または不飽和の炭素数１〜２０である１価の炭化水素基が好ましい。具体的な例としては、メチル基、エチル基、ｎ−プロピル基、ｉｓｏ−プロピル基、ｎ−ブチル基、ｉｓｏ−ブチル基、ｓｅｃ−ブチル基、ｔｅｒｔ−ブチル基、ｎ−ペンチル基などが挙げられる。

R is preferably a linear or branched saturated or unsaturated monovalent hydrocarbon group having 1 to 20 carbon atoms. Specific examples include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group, tert-butyl group, n-pentyl group and the like. It is done.

The electrolytic solution for an electrolytic capacitor of the present invention comprises at least one of an acid (A1) and a salt (A2) of the acid (A1), an electrolyte (E) as a main component, and, if necessary, a solvent (F).
The cation component of the electrolyte (E) and the cation component for the anion of the salt (A2) are preferably at least one selected from ammonium, primary ammonium, secondary ammonium, tertiary ammonium, and quaternary ammonium.

Specific examples of primary ammonium include the following cations.
Methylammonium, ethylammonium, propylammonium, isopropylammonium, butylammonium, ethylenediammonium, ethylenediaminemonoammonium, 1,2-diammoniumpropane, 1,2-diaminopropanemonoammonium and the like.

Specific examples of secondary ammonium include the following cations.
Dimethylammonium, diethylammonium, methylethylammonium, methylpropylammonium, methylisopropylammonium, dipropylammonium, diisopropylammonium, methylformylmethylammonium, methylformylethylammonium, pyrrolidineammonium, 2-pyrrolidoneammonium, piperidineammonium, pipecolineammonium, Pipecolate ammonium, piperazine monoammonium, piperazine diammonium, piperidone ammonium, pyrazolidine monoammonium, pyrazolidinediammonium, 2-pyrazolinammonium, pyrazoleammonium, pyrazolone monoammonium, pyrazolonediammonium and the like.

Specific examples of the tertiary ammonium include the following cations.
Trimethylammonium, triethylammonium, dimethylethylammonium, dimethylpropylammonium, dimethylisopropylammonium, diethylmethylammonium, methylethylpropylammonium, diethylmethylammonium, diisopropylmethylammonium, dimethylformylmethylammonium, dimethylformylethylammonium , Diethylformylmethylammonium, diethylformylethylammonium, dimethylmethoxycarbonylmethylammonium, diethylmethoxycarbonylmethylammonium, dimethylcyanomethylammonium, dimethylcyanoethylammonium, diethylcyanomethylammonium, diethylcyanoethylan Ni, dimethylmethoxymethylammonium, dimethylmethoxyethylammonium, diethylmethoxymethylammonium, diethylmethoxyethylammonium, dimethylacetylmethylammonium, diethylacetylmethylammonium, dimethylhydroxymethylammonium, dimethylhydroxyethylammonium, diethylhydroxymethylammonium, diethylhydroxyethyl Ammonium, pyridine ammonium, pyridyl ammonium, 1,5-diazabicyclo (4,3,0) noneneammonium, 1,8-diazabicyclo (5,4,0) -undecene-7 and the like.

  Specific examples of the quaternary ammonium include a tetraalkylammonium cation, an amidinium cation, and a guanidinium cation.

The following are mentioned as a tetraalkylammonium cation.
Tetramethylammonium, ethyltrimethylammonium, diethyldimethylammonium, triethylmethylammonium, tetraethylammonium, trimethyl-n-propylammonium, trimethylisopropylammonium, dimethyldi-n-propylammonium, dimethyldiisopropylammonium, dimethyl-n-propylisopropylammonium, methyltrimethylammonium N-propylammonium, methyltriisopropylammonium, methyldi-n-propylisopropylammonium, methyl-n-propyldiisopropylammonium, triethyl-n-propylammonium, triethylisopropylammonium, diethyldi-n-propylammonium, diethyldiisopropylammonium, diethyl − -Propylisopropylammonium, ethyltri-npropylammonium, ethyltriisopropylammonium, ethyldi-n-propylisopropylammonium, ethyl-n-propyldiisopropylammonium, diethyldimethyl-n-propylammonium, ethyldimethyl-n-propylammonium, diethylmethyl Isopropylammonium, ethyldimethylisopropylammonium, ethylmethyldiisopropylammonium, ethylmethyl-n-propylisopropylammonium, tetra-n-propylammonium, tetraisopropylammonium, di-n-propyldiisopropylammonium, tri-n-propylisopropylammonium, etc. is there.

The following are mentioned as an amidinium cation.

(1) Imidazoliums 1,2,3,4-tetramethylimidazolinium, 1,3,4-trimethyl-2-ethylimidazolinium, 1,3-dimethyl-2,4-diethylimidazolinium 1,2-dimethyl-3,4-diethylimidazolinium, 1-methyl-2,3,4-triethylimidazolinium, 1,2,3,4-tetraethylimidazolinium, 1,2,3- Trimethylimidazolinium, 1,3-dimethyl-2-ethylimidazolinium, 1-ethyl-2,3-dimethylimidazolinium, 1,2,3-triethylimidazolinium, 4-cyano-1,2, 3-trimethylimidazolinium, 3-cyanomethyl-1,2-dimethylimidazolinium, 2-cyanomethyl-1,3-dimethylimidazolinium, 4-acetyl- , 2,3-trimethylimidazolinium, 3-acetylmethyl-1,2-dimethylimidazolinium, 4-methylcarbooxymethyl-1,2,3-trimethylimidazolinium, 3-methylcarbooxymethyl-1 , 2-dimethylimidazolinium, 4-methoxy-1,2,3-trimethylimidazolinium, 3-methoxymethyl-1,2-dimethylimidazolinium, 4-formyl-1,2,3-trimethylimidazoli Ni, 3-formylmethyl-1,2-dimethylimidazolinium, 3-hydroxyethyl-1,2-dimethylimidazolinium, 4-hydroxymethyl-1,2,3-trimethylimidazolinium, 2-hydroxyethyl -1,3-dimethylimidazolinium and the like.

(2) Imidazoliums 1,3-dimethylimidazolium, 1,3-diethylimidazolium, 1-ethyl-3-methylimidazolium, 1,2,3-trimethylimidazolium, 1,2,3,4- Tetramethylimidazolium, 1,3-dimethyl-2-ethylimidazolium, 1,2-dimethyl-3-ethyl-imidazolium, 1,2,3-triethylimidazolium, 1,2,3,4-tetraethylimidazolium Lithium, 1,3-dimethyl-2-phenylimidazolium, 1,3-dimethyl-2-benzylimidazolium, 1-benzyl-2,3-dimethyl-imidazolium, 4-cyano-1,2,3-trimethyl Imidazolium, 3-cyanomethyl-1,2-dimethylimidazolium, 2-cyanomethyl-1,3-dimethyl-imidazolium 4-acetyl-1,2,3-trimethylimidazolium, 3-acetylmethyl-1,2-dimethylimidazolium, 4-methylcarbooxymethyl-1,2,3-trimethylimidazolium, 3-methylcarbooxy Methyl-1,2-dimethylimidazolium, 4-methoxy-1,2,3-trimethylimidazolium, 3-methoxymethyl-1,2-dimethylimidazolium, 4-formyl-1,2,3-trimethylimidazolium 3-formylmethyl-1,2-dimethylimidazolium, 3-hydroxyethyl-1,2-dimethylimidazolium, 4-hydroxymethyl-1,2,3-trimethylimidazolium, 2-hydroxyethyl-1,3 -Dimethylimidazolium and the like.

(3) Tetrahydropyrimidiniums 1,3-dimethyl-1,4,5,6-tetrahydropyrimidinium, 1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium, 1, 2,3,4-tetramethyl-1,4,5,6-tetrahydropyrimidinium, 1,2,3,5-tetramethyl-1,4,5,6-tetrahydropyrimidinium, 8-methyl- 1,8-diazabicyclo [5,4,0] -7-undecenium, 5-methyl-1,5-diazabicyclo [4,3,0] -5-nonenium, 4-cyano-1,2,3-trimethyl- 1,4,5,6-tetrahydropyrimidinium, 3-cyanomethyl-1,2-dimethyl-1,4,5,6-tetrahydropyrimidinium, 2-cyanomethyl-1,3-dimethyl-1,4 5,6-tetra Dropyrimidinium, 4-acetyl-1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium, 3-acetylmethyl-1,2-dimethyl-1,4,5,6-tetrahydro Pyrimidinium, 4-methylcarbooxymethyl-1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium, 3-methylcarbooxymethyl-1,2-dimethyl-1,4,5 , 6-tetrahydropyrimidinium, 4-methoxy-1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium, 3-methoxymethyl-1,2-dimethyl-1,4,5, 6-tetrahydropyrimidinium, 4-formyl-1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium, 3-formylmethyl-1,2-dimethyl-1,4 5,6-tetrahydropyrimidinium, 3-hydroxyethyl-1,2-dimethyl-1,4,5,6-tetrahydropyrimidinium, 4-hydroxymethyl-1,2,3-trimethyl-1,4 5,6-tetrahydropyrimidinium, 2-hydroxyethyl-1,3-dimethyl-1,4,5,6-tetrahydropyrimidinium and the like.

(4) Dihydropyrimidiniums 1,3-dimethyl-1,4- or -1,6-dihydropyrimidinium [these are referred to as 1,3-dimethyl-1,4 (6) -dihydropyrimidinium The same expression is used hereinafter. 1,2,3-trimethyl-1,4 (6) -dihydropyrimidinium, 1,2,3,4-tetramethyl-1,4 (6) -dihydropyrimidinium, 1,2,3 5-tetramethyl-1,4 (6) -dihydropyrimidinium, 8-methyl-1,8-diazabicyclo [5,4,0] -7,9 (10) -undecadienium, 5-methyl- 1,5-diazabicyclo [4,3,0] -5,7 (8) -nonadienium, 4-cyano-1,2,3-trimethyl-1,4 (6) -dihydropyrimidinium, 3-cyanomethyl- 1,2-dimethyl-1,4 (6) -dihydropyrimidinium, 2-cyanomethyl-1,3-dimethyl-1,4 (6) -dihydropyrimidinium, 4-acetyl-1,2,3- Trimethyl-1,4 (6) -dihydropyrimidinium, 3 Acetylmethyl-1,2-dimethyl-1,4 (6) -dihydropyrimidinium, 4-methylcarbooxymethyl-1,2,3-trimethyl-1,4 (6) -dihydropyrimidinium, 3- Methylcarbooxymethyl-1,2-dimethyl-1,4 (6) -dihydropyrimidinium, 4-methoxy-1,2,3-trimethyl-1,4 (6) -dihydropyrimidinium, 3-methoxy Methyl-1,2-dimethyl-1,4 (6) -dihydropyrimidinium, 4-formyl-1,2,3-trimethyl-1,4 (6) -dihydropyrimidinium, 3-formylmethyl-1 , 2-Dimethyl-1,4 (6) -dihydropyrimidinium, 3-hydroxyethyl-1,2-dimethyl-1,4 (6) -dihydropyrimidinium, 4-hydroxymethyl-1,2,3 Trimethyl-1,4 (6) - dihydropyrimidinium, 1,3 2-hydroxyethyl dimethyl-1,4 (6) - such as hydro pyrimidinium.

The following are mentioned as a guanidinium cation.

(1) Guanidiniums having an imidazolinium skeleton 2-dimethylamino-1,3,4-trimethylimidazolinium, 2-diethylamino-1,3,4-trimethylimidazolinium, 2-diethylamino-1,3- Dimethyl-4-ethylimidazolinium, 2-dimethylamino-1-methyl-3,4-diethylimidazolinium, 2-diethylamino-1-methyl-3,4-diethylimidazolinium, 2-diethylamino-1, 3,4-triethylimidazolinium, 2-dimethylamino-1,3-dimethylimidazolinium, 2-diethylamino-1,3-dimethylimidazolinium, 2-dimethylamino-1-ethyl-3-methylimidazoli Ni, 2-diethylamino-1,3-diethylimidazolinium, 1,5,6,7- Torahydro-1,2-dimethyl-2H-imide [1,2a] imidazolinium, 1,5-dihydro-1,2-dimethyl-2H-imide [1,2a] imidazolinium, 1,5,6 7-tetrahydro-1,2-dimethyl-2H-pyrimido [1,2a] imidazolinium, 1,5-dihydro-1,2-dimethyl-2H-pyrimido [1,2a] imidazolinium, 2-dimethylamino -4-cyano-1,3-dimethylimidazolinium, 2-dimethylamino-3-cyanomethyl-1-methylimidazolinium, 2-dimethylamino-4-acetyl-1,3-dimethylimidazolinium, 2- Dimethylamino-3-acetylmethyl-1-methylimidazolinium, 2-dimethylamino-4-methylcarbooxymethyl-1,3-dimethylimidazole Ni, 2-dimethylamino-3-methylcarbooxymethyl-1-methylimidazolinium, 2-dimethylamino-4-methoxy-1,3-dimethylimidazolinium, 2-dimethylamino-3-methoxymethyl-1 -Methylimidazolinium, 2-dimethylamino-4-formyl-1,3-dimethylimidazolinium, 2-dimethylamino-3-formylmethyl-1-methylimidazolinium, 2-dimethylamino-3-hydroxyethyl -1-methylimidazolinium, 2-dimethylamino-4-hydroxymethyl-1,3-dimethylimidazolinium, and the like.

(2) Guanidiniums having an imidazolium skeleton 2-dimethylamino-1,3,4-trimethylimidazolium, 2-diethylamino-1,3,4-trimethylimidazolium, 2-diethylamino-1,3-dimethyl-4 -Ethylimidazolium, 2-dimethylamino-1-methyl-3,4-diethylimidazolium, 2-diethylamino-1-methyl-3,4-diethylimidazolium, 2-diethylamino-1,3,4-triethylimidazole Lithium, 2-dimethylamino-1,3-dimethylimidazolium, 2-diethylamino-1,3-dimethylimidazolium, 2-dimethylamino-1-ethyl-3-methylimidazolium, 2-diethylamino-1,3- Diethylimidazolium, 1,5,6,7-tetrahydro-1,2- Methyl-2H-imide [1,2a] imidazolium, 1,5-dihydro-1,2-dimethyl-2H-imide [1,2a] imidazolium, 1,5,6,7-tetrahydro-1,2- Dimethyl-2H-pyrimido [1,2a] imidazolium, 1,5-dihydro-1,2-dimethyl-2H-pyrimido [1,2a] imidazolium, 2-dimethylamino-4-cyano-1,3-dimethyl Imidazolium, 2-dimethylamino-3-cyanomethyl-1-methylimidazolium, 2-dimethylamino-4-acetyl-1,3-dimethylimidazolinium, 2-dimethylamino-3-acetylmethyl-1-methylimidazole 2-dimethylamino-4-methylcarbooxymethyl-1,3-dimethylimidazolium, 2-dimethylamino-3-methyl Carbooxymethyl-1-methylimidazolium, 2-dimethylamino-4-methoxy-1,3-dimethylimidazolium, 2-dimethylamino-3-methoxymethyl-1-methylimidazolium, 2-dimethylamino-4- Formyl-1,3-dimethylimidazolium, 2-dimethylamino-3-formylmethyl-1-methylimidazolium, 2-dimethylamino-3-hydroxyethyl-1-methylimidazolium, 2-dimethylamino-4-hydroxy Methyl-1,3-dimethylimidazolium and the like.

(3) Guanidiniums having a tetrahydropyrimidinium skeleton 2-dimethylamino-1,3,4-trimethyl-1,4,5,6-tetrahydropyrimidinium, 2-diethylamino-1,3,4-trimethyl- 1,4,5,6-tetrahydropyrimidinium, 2-diethylamino-1,3-dimethyl-4-ethyl-1,4,5,6-tetrahydropyrimidinium, 2-dimethylamino-1-methyl-3 , 4-Diethyl-1,4,5,6-tetrahydropyrimidinium, 2-diethylamino-1-methyl-3,4-diethyl-1,4,5,6-tetrahydropyrimidinium, 2-diethylamino-1 , 3,4-Triethyl-1,4,5,6-tetrahydropyrimidinium, 2-dimethylamino-1,3-dimethyl-1,4,5,6-tetra Dropyrimidinium, 2-diethylamino-1,3-dimethyl-1,4,5,6-tetrahydropyrimidinium, 2-dimethylamino-1-ethyl-3-methyl-1,4,5,6-tetrahydro Pyrimidinium, 2-diethylamino-1,3-diethyl-1,4,5,6-tetrahydropyrimidinium, 1,3,4,6,7,8-hexahydro-1,2-dimethyl-2H-imide [1,2a] pyrimidinium, 1,3,4,6-tetrahydro-1,2-dimethyl-2H-imide [1,2a] pyrimidinium, 1,3,4,6,7,8-hexahydro-1,2 -Dimethyl-2H-pyrimido [1,2a] pyrimidinium, 1,3,4,6-tetrahydro-1,2-dimethyl-2H-pyrimido [1,2a] pyrimidinium, 2-dimethylamino- -Cyano-1,3-dimethyl-1,4,5,6-tetrahydropyrimidinium, 2-dimethylamino-3-cyanomethyl-1-methyl-1,4,5,6-tetrahydropyrimidinium, 2- Dimethylamino-4-acetyl-1,3-dimethyl-1,4,5,6-tetrahydropyrimidinium, 2-dimethylamino-3-acetylmethyl-1-methyl-1,4,5,6-tetrahydropyrim Midinium, 2-dimethylamino-4-methylcarbooxymethyl-1,3-dimethyl-1,4,5,6-tetrahydropyrimidinium, 2-dimethylamino-3-methylcarbooxymethyl-1-methyl- 1,4,5,6-tetrahydropyrimidinium, 2-dimethylamino-4-methoxy-1,3-dimethyl-1,4,5,6-tetrahydropyrimidine , 2-dimethylamino-3-methoxymethyl-1-methyl-1,4,5,6-tetrahydropyrimidinium, 2-dimethylamino-4-formyl-1,3-dimethyl-1,4,5 6-tetrahydropyrimidinium, 2-dimethylamino-3-formylmethyl-1-methyl-1,4,5,6-tetrahydropyrimidinium, 2-dimethylamino-3-hydroxyethyl-1-methyl-1, 4,5,6-tetrahydropyrimidinium, 2-dimethylamino-4-hydroxymethyl-1,3-dimethyl-1,4,5,6-tetrahydropyrimidinium and the like.

(4) Guanidiniums having a dihydropyrimidinium skeleton 2-dimethylamino-1,3,4-trimethyl-1,4 (6) -dihydropyrimidinium, 2-diethylamino-1,3,4-trimethyl-1 , 4 (6) -dihydropyrimidinium, 2-diethylamino-1,3-dimethyl-4-ethyl-1,4 (6) -dihydropyrimidinium, 2-dimethylamino-1-methyl-3,4- Diethyl-1,4 (6) -dihydropyrimidinium, 2-diethylamino-1-methyl-3,4-diethyl-1,4 (6) -dihydropyrimidinium, 2-diethylamino-1,3,4 Triethyl-1,4 (6) -dihydropyrimidinium, 2-dimethylamino-1,3-dimethyl-1,4 (6) -dihydropyrimidinium, 2-diethylamino-1, -Dimethyl-1,4 (6) -dihydropyrimidinium, 2-dimethylamino-1-ethyl-3-methyl-1,4 (6) -dihydropyrimidinium, 2-diethylamino-1,3-diethyl- 1,4 (6) -dihydropyrimidinium, 1,6,7,8-tetrahydro-1,2-dimethyl-2H-imide [1,2a] pyrimidinium, 1,6-dihydro-1,2-dimethyl- 2H-imide [1,2a] pyrimidinium, 1,6,7,8-tetrahydro-1,2-dimethyl-2H-pyrimido [1,2a] pyrimidinium, 1,6-dihydro-1,2-dimethyl-2H- Pyrimido [1,2a] pyrimidinium, 2-dimethylamino-4-cyano-1,3-dimethyl-1,4 (6) -dihydropyrimidinium, 2-dimethylamino-3-cyanomethyl 1-methyl-1,4 (6) -dihydropyrimidinium, 2-dimethylamino-4-acetyl-1,3-dimethyl-1,4 (6) -dihydropyrimidinium, 2-dimethylamino-3- Acetylmethyl-1-methyl-1,4 (6) -dihydropyrimidinium, 2-dimethylamino-4-methylcarbooxymethyl-1,3-dimethyl-1,4 (6) -dihydropyrimidinium, 2 -Dimethylamino-3-methylcarbooxymethyl-1-methyl-1,4 (6) -dihydropyrimidinium, 2-dimethylamino-4-methoxy-1,3-dimethyl-1,4 (6) -dihydro Pyrimidinium, 2-dimethylamino-3-methoxymethyl-1-methyl-1,4 (6) -dihydropyrimidinium, 2-dimethylamino-4-formyl-1,3-dimethyl -1,4 (6) -dihydropyrimidinium, 2-dimethylamino-3-formylmethyl-1-methyl-1,4 (6) -dihydropyrimidinium, 2-dimethylamino-3-hydroxyethyl-1 -Methyl-1,4 (6) -dihydropyrimidinium, 2-dimethylamino-4-hydroxymethyl-1,3-dimethyl-1,4 (6) -dihydropyrimidinium, and the like.

Ammonium, primary ammonium, secondary ammonium, tertiary ammonium, and quaternary ammonium may be used alone or in combination of two or more. It is preferable that the cation component of the main component electrolyte constituting the electrolytic solution and the cation component for the anion of the acid (A1) are the same component.

Among these, ammonium is preferable as an electrolyte for a medium-high voltage class electrolytic capacitor. Preferred electrolytes for low-pressure class electrolytic capacitors are an aminidium cation and a guanidinium cation. Preferred as the aminidium cation are imidazoliniums, and particularly preferred are 1,2,3,4-tetramethylimidazolinium, 1,2,3-trimethylimidazolinium, and 1-ethyl-2. , 3-dimethylimidazolinium. Preferred as the guanidinium cation are guanidiniums having an imidazolinium skeleton, and particularly preferred are 2-dimethylamino-1,3,4-trimethylimidazolinium, 2-dimethylamino-1,3- Dimethylimidazolinium, 2-dimethylamino-1-ethyl-3-methylimidazolinium.

  In the present invention, the anionic acid constituting the electrolyte (E) is preferably an organic carboxylic acid, a mono- and dialkyl phosphate ester, a phenol, a triazole, a compound having a tetrazole skeleton, a fluorocarboxylic acid, a boron complex, or the like. Can be mentioned.

Specific examples of the organic carboxylic acid include the following compounds.
(1) C2-C15 divalent to tetravalent polycarboxylic acid: aliphatic polycarboxylic acid [saturated polycarboxylic acid (oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, speric acid, Azelaic acid, 2-methyl azelaic acid, sebacic acid, 1,5-octanedicarboxylic acid, 4,5-octanedicarboxylic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,6-decanedicarboxylic acid Acid, 5,6-decanedicarboxylic acid, 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,15-pentadecanedicarboxylic acid , Methylmalonic acid, ethylmalonic acid, propylmalonic acid, butylmalonic acid, pentylmalonic acid, hexylmalonic acid, Methylmalonic acid, diethylmalonic acid, methylpropylmalonic acid, methylbutylmalonic acid, ethylpropylmalonic acid, dipropylmalonic acid, methylsuccinic acid, ethylsuccinic acid, 2,2-dimethylsuccinic acid, 2,3-dimethylsuccinic acid, 2-methylglutaric acid, 3-methylglutaric acid, 3-methyl-3-ethylglutaric acid, 3,3-diethylglutaric acid, 3,3-dimethylglutaric acid, 3-methyladipic acid, etc.), unsaturated polycarboxylic acid Acid (maleic acid, fumaric acid, itaconic acid, citraconic acid etc.)], aromatic polycarboxylic acid [phthalic acid, isophthalic acid, terephthalic acid etc.], S-containing polycarboxylic acid [thiodipropionic acid etc.], etc.

(2) C2-C20 oxycarboxylic acid: aliphatic oxycarboxylic acid [glycolic acid, lactic acid, lactic butyric acid, castor oil fatty acid, etc.]; aromatic oxycarboxylic acid [salicylic acid, mandelic acid, 4-hydroxybenzoic acid, 2 , 4-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 1-hydroxy-2-naphthoic acid, 3-hydroxy-2-naphthoic acid, 6-hydroxy-2-naphthoic acid, etc. ]etc;

(3) Monocarboxylic acid having 1 to 30 carbon atoms: aliphatic monocarboxylic acid [saturated monocarboxylic acid (formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid , Urallylic acid, myristic acid, stearic acid, behenic acid, undecanoic acid, etc.), unsaturated monocarboxylic acids (acrylic acid, methacrylic acid, crotonic acid, oleic acid, etc.)]; aromatic monocarboxylic acids [benzoic acid, cinnamon Acid, naphthoic acid, toluic acid, ethyl benzoic acid, propyl benzoic acid, isopropyl benzoic acid, butyl benzoic acid, isobutyl benzoic acid, sec-butyl benzoic acid, tert-butyl benzoic acid, hydroxybenzoic acid, ethoxy benzoic acid, propoxy benzoic acid Acid, isopropoxybenzoic acid, butoxybenzoic acid, isobutoxybenzoic acid, second butoxybenzoic acid Acid, tertiary butoxybenzoic acid, aminobenzoic acid, N-methylaminobenzoic acid, N-ethylaminobenzoic acid, N-propylaminobenzoic acid, N-isopropylaminobenzoic acid, N-butylaminobenzoic acid, N-isobutyl Aminobenzoic acid, N-secondary butylaminobenzoic acid, N-tertiarybutylaminobenzoic acid, N, N-dimethylaminobenzoic acid, N, N-diethylaminobenzoic acid, etc.].

Examples of the mono and dialkyl phosphate esters include mono and dialkyl phosphate esters represented by the following general formula (9). R ₃ and R ₄ are hydrogen or an alkyl group having 1 to 10 carbon atoms, and at least one is an alkyl group. The number of carbon atoms of R ₃ and R ₄ is preferably 1 to 10 from the viewpoint of impedance characteristics and withstand voltage characteristics. More preferably, it is 3-8.

Specific examples include monomethyl phosphate ester, dimethyl phosphate ester, monoethyl phosphate ester, diethyl phosphate ester, monopropyl phosphate ester, dipropyl phosphate ester, monoisopropyl phosphate ester, diisopropyl phosphate ester, monobutyl phosphate ester. , Dibutyl phosphate, monopentyl phosphate, dipentyl phosphate, monohexyl phosphate, dihexyl phosphate, monoheptyl phosphate, diheptyl phosphate, monooctyl phosphate, dioctyl phosphate, mono- 2-ethylhexyl phosphate, di-2-ethylhexyl phosphate, monononyl phosphate, dinonyl phosphate, monodecyl phosphate, didecyl phosphate Esters, monoisodecyl phosphate esters, and the like diisodecyl phosphate ester.

Specific examples of phenols include the following compounds.
Monohydric phenols (including phenols and naphthols): phenol, alkyl (C1-15) phenols (cresol, xylenol, ethylphenol, n- or isopropylphenol, isododecylphenol, etc.), methoxyphenols (Eugenol, guaiacol, etc.), α-naphthol, β-naphthol, cyclohexylphenol, etc .;
Polyhydric phenols: catechol, resorcin, pyrogallol, phloroglucin, bisphenol A, bisphenol F, bisphenol S, etc.
As said phenols, a C6-C20 thing is preferable.

Specific examples of the compound having a triazole or tetrazole skeleton include the following compounds.
1-H-1,2,4-triazole, 1,2,3-triazole, 1,2,3-benzotriazole, carboxybenzotriazole, 3-mercapto-1,2,4-triazole, 1,2,3 -Triazole-4,5-dicarboxylic acid, 3-mercapto-5-methyl-1,2,4-triazole, 1,2,3,4-tetrazole and the like.
As said compound, a C6-C20 thing is preferable.

Specific examples of the fluorocarboxylic acid include the following compounds.
Fluorocarboxylic acid RfCOOH (Rf is a fluoroalkyl group having 1 to 30 carbon atoms): (trifluoroacetic acid, perfluoropropionic acid, perfluoroisopropionic acid, perfluorobutyric acid, perfluorovaleric acid, perfluorocaproic acid, Fluoroperargonic acid, perfluorocapric acid, perfluoroundecyl acid, perfluorotridecanoic acid, perfluorotetradecanoic acid, perfluoron-octanoic acid, perfluorolauric acid, perfluoropalmitic acid, etc.)

Specific examples of the boron complex include the following compounds.
(1) Alcoholic hydroxyl group-containing compound complex of boric acid; boric acid ethylene glycol complex, trimethylene glycol borate complex, etc .; (2) carboxyl group-containing compound ester complex of boric acid; borodisoxalic acid ester complex, borodiglycolic acid ester Complex; (3) phosphoric acid and / or phosphoric acid ester complex of boric acid; boric acid methyl phosphate complex, boric acid ethyl phosphate complex, etc .; as the details of boron complex, those described in Japanese Patent No. 2966451 can be used. .

These acids may be used alone or in combination of two or more.

Of these, organic carboxylic acids are preferred. Further, preferred as the electrolyte for a low-pressure class capacitor are aromatic monocarboxylic acid, aromatic polycarboxylic acid, aromatic oxycarboxylic acid, and aliphatic unsaturated polycarboxylic acid, and particularly preferred are benzoic acid, phthalic acid, and salicylic acid. Maleic acid. Further, saturated polycarboxylic acids and aromatic monocarboxylic acids are preferred as the electrolyte for medium- and high-voltage capacitors, and particularly preferred are adipic acid, azelaic acid, 2-methylazeleic acid, sebacic acid, and 1,5-octanedicarboxylic acid. Acid, 4,5-octanedicarboxylic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,6-decanedicarboxylic acid, 5,6-decanedicarboxylic acid, and benzoic acid.

As the solvent (F) for dissolving the electrolyte (E), the organic solvents described below are preferably used. Specific examples of the organic solvent are as follows, and two or more kinds can be used in combination.

(1) Alcohols monohydric alcohols (methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, diacetone alcohol, benzyl alcohol, amino alcohol, furfuryl alcohol, etc.), dihydric alcohols (ethylene glycol, propylene glycol, 1, 3 -Propanediol, 1,4-butanediol, 1,5-propanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, etc.), trihydric alcohol (glycerin, etc.), tetravalent or higher alcohol (hexitol, etc.) Such;

(2) Ether monoethers (ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, ethylene glycol monophenyl ether, tetrahydrofuran, 3-methyltetrahydrofuran, etc.), diethers (ethylene glycol dimethyl ether, ethylene Glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, etc.);

(3) Amides formamides (N-methylformamide, N, N-dimethylformamide, N-ethylformamide, N, N-diethylformamide, etc.), acetamides (N-methylacetamide, N, N-dimethylacetamide, N -Ethylacetamide, N, N-diethylacetamide, etc.), propionamides (N, N-dimethylpropionamide, etc.), pyrrolidones (N-methylpyrrolidone, N-ethylpyrrolidone, etc.), hexamethylphosphorylamide, etc .;

(4) Oxazolidinones N-methyl-2-oxazolidinone, 3,5-dimethyl-2-oxazolidinone, etc .;

(5) Lactones γ-butyrolactone (hereinafter referred to as Γ-butyrolactone), α-acetyl-γ-butyrolactone, β-butyrolactone, γ-valerolactone, δ-valerolactone, and the like;

(6) Nitriles Acetonitrile, propionitrile, butyronitrile, acrylonitrile, methacrylonitrile, benzonitrile, etc .;

(7) carbonates such as ethylene carbonate, propion carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate;

(8) Sulfoxides dimethyl sulfoxide, sulfolane, 3-methyl sulfolane, 2,4-dimethyl sulfolane,

(9) Ketone solvents acetone, methyl ethyl ketone, diethyl ketone, acetophenone, cyclohexanone, cyclopentanone and the like.

(10) Polyether solvent polyethylene glycol (triethylene glycol, tetraethylene glycol, etc.), polypropylene glycol (tripropylene glycol, etc.), polyoxyethylene polyoxypropylene glycol, polyoxyethylene alkyl ether (polyoxyethylene butyl ether, polyoxy) Ethylene lauryl ether), polyoxyethylene alkenyl ether, polyoxypropylene alkyl ether (polyoxypropylene butyl ether, etc.), polyoxypropylene alkenyl ether, polyoxyethylene fatty acid ester (polyethylene glycol monostearate, polyethylene glycol monooleate, etc.) , Polyoxypropylene fatty acid ester (polypropylene monostearate) , Etc. monooleate polypropylene glycol), etc.

(11) Other organic solvents 1,3-dimethyl-2-imidazolidinone, aromatic solvents (toluene, xylene, etc.) paraffinic solvents (normal paraffin, isoparaffin, etc.), etc .;

As an organic solvent, a C1-C20 thing is preferable and a C1-C10 thing is more preferable. Of the organic solvents, γ-butyrolactone, sulfolane, dimethyl sulfoxide, ethylene glycol, diethylene glycol and the like are more preferable.

  The weight of the electrolyte (E) constituting the electrolytic solution is preferably 1 to 70% by weight and more preferably 5 to 40% by weight with respect to the total weight of the electrolytic solution.

In addition to the acid (A1), the salt (A2) of the acid (A1), the electrolyte (E), and the solvent (F), various additives usually used in the electrolyte are added to the electrolytic solution of the present invention, if necessary. be able to.
Examples of the additive include phosphoric acid derivatives (for example, phosphoric acid, phosphoric acid esters, etc.), boric acid derivatives (for example, boric acid, complex compounds of boric acid and polysaccharides [mannit, sorbit, etc.], boric acid and Complex compounds with polyhydric alcohols (ethylene glycol, glycerin, etc.), nitro compounds (for example, o-nitrobenzoic acid, p-nitrobenzoic acid, m-nitrobenzoic acid, o-nitrophenol, p-nitrophenol, etc.) ) And the like.
If necessary, a small amount of a carboxylic acid having a primary carboxyl group, a carboxylic acid having an aromatic carboxyl group, or the like can be mixed for the purpose of improving chemical conversion and further improving specific conductivity. Specific examples include adipic acid, sebacic acid, azelaic acid, 1,6-decanedicarboxylic acid, 2-methyl azelaic acid, benzoic acid and the like.
The total amount of the additives is preferably 10% by weight or less with respect to the total weight of the electrolyte.

  3-12 are preferable and, as for pH of the electrolyte solution of this invention, More preferably, it is 5-10. At the time of production, conditions are selected such that the pH of the electrolytic solution is within this range. The pH of the electrolytic solution is an analytical value of 25 ° C. of the electrolytic solution stock solution.

  The present invention also includes an electrolytic capacitor using the above electrolytic solution of the present invention. The material of the electrolytic capacitor of the present invention is not particularly limited as long as the electrolytic solution is used. Therefore, the case where the electrolytic solution of the present invention is used for an electrolytic capacitor that has been used conventionally and a newly proposed electrolytic capacitor is included within the scope of the present invention. A typical example of the configuration of an electrolytic capacitor is a wound element structure. The cathode foil is disposed opposite to the anode foil, and is wound with a separator interposed therebetween. This is put into an aluminum outer case, and the case is sealed with a sealing agent such as phenol laminate, polypropylene, polyphenyl sulfide, etc., through a packing such as butyl rubber, ethylene propylene rubber, silicone rubber, etc., thereby forming an electrolytic capacitor. . The electrolytic solution of the present invention is used by being impregnated in a separator sandwiched between an anode foil and a cathode foil. Kraft paper, Manila paper, etc. are generally used for the separator, but are not particularly limited thereto.

EXAMPLES Next, specific examples of the present invention will be described, but the present invention is not limited thereto. Specific compositions of Examples 1 to 15 are shown in Table 1, and specific compositions of Comparative Examples 1 to 14 are shown in Table 2. Hereinafter, unless otherwise indicated, parts and% are parts by weight and% by weight.

Production Example 1 [Production of 1,2,3,4-tetramethylimidazolinium phthalate]
By adding 2,4-dimethylimidazoline (0.1 mol) dropwise to a methanol solution (74%) of dimethyl carbonate (0.2 mol) and stirring at 120 ° C. for 15 hours, 1,2,3,4-tetra Methyl imidazolinium methyl carbonate salt was produced. A salt exchange reaction is performed by adding phthalic acid (0.1 mol) to a 1,2,3,4-tetramethylimidazolinium methyl carbonate salt (0.1 mol) solution, and 1,2,3,4-tetramethyl is obtained. An imidazolinium phthalate solution was obtained. The solution was heated and distilled at 110 ° C. under a reduced pressure of 1.0 kPa or less, and methanol as a solvent was removed to obtain 1,2,3,4-tetramethylimidazolinium phthalate. The yield was 100 mol%.

Production Example 2 [Production of tetraethylammonium phthalate]
Triethylamine (0.1 mol) was added dropwise to a methanol solution (74%) of diethyl carbonate (0.1 mol) and stirred at 120 ° C. for 15 hours to produce tetraethylammonium ethyl carbonate salt. A salt exchange reaction was performed by adding phthalic acid (0.1 mol) to a tetraethylammonium ethyl carbonate salt (0.1 mol) solution to obtain a tetramethylammonium phthalate solution. The above solution was heated and distilled at 110 ° C. under a reduced pressure of 1.0 kPa or less to remove ethanol as a solvent to obtain tetraethylammonium phthalate. The yield was 100 mol%.

Production Example 3 [Acid (A1-1)]
In a 3 L 4-neck flask, 3 mol of polyoxyethylene lauryl ether (general formula (10)) is heated and stirred at 55 ° C. Add 1 mol of diphosphorus pentoxide little by little at 55 ± 5 ° C. while keeping water out. The temperature was raised to 110 ± 5 ° C., stirred for 3 hours, cooled after the reaction, and in the general formula (2), an acid represented by X = C ₁₂ H ₂₅ −, n = 8, R ₁ = −C ₂ H ₄ — (A11-1) 66 mol%, and in the general formula _{(4), X = Y =} C 12 H 25 -, k = 1, m = 8, n = 8, R 1 = -C 2 H 4 - with the indicated A mixture of 34 mol% of acid (A13-1) and acid (A1-1) were obtained. The molar ratio of each component was measured by P-NMR.

Production Example 4 [Acid (A1-2)]
In a 3 L four-necked flask, 3 mol of polyethylene glycol (Mw = 400) is heated and stirred at 55 ° C. 2 mol of diphosphorus pentoxide is added little by little at 55 ± 5 ° C. while keeping water out. The temperature was raised to 110 ± 5 ° C., the mixture was stirred for 3 hours, cooled after the reaction, and in general formula (2), an acid represented by X = H, n = 8, R ₁ = —C ₂ H ₄ — (A11-2 ) 53%, in general formula (3), n = 8, R ₁ = -C ₂ H ₄ — 27% acid (A12-2), in general formula (4), X = Y = H, m = N = 8, k = 1, R ₁ = R ₂ = 13% of acid (A13-2) represented by —C ₂ H ₄ —, in general formula (5), m = n = 8, k = 1, A mixture (A1-2) of 7% of an acid (A14-2) represented by R ₁ = R ₂ = —C ₂ H ₄ — was obtained. The molar ratio of each component was measured by P-NMR.

Production Example 5 [Acid (A1-3)]
In a 3 L four-necked flask, 3 mol of polypropylene glycol (Mw = 400) is heated and stirred at 55 ° C. 2 mol of diphosphorus pentoxide is added little by little at 55 ± 5 ° C. while keeping water out. The temperature was raised to 110 ± 5 ° C., the mixture was stirred for 3 hours, cooled after the reaction, and in the general formula (2), an acid represented by X = H, n = 8, R ₁ = —CH ₂ CH (CH ₃ ) — ( A11-3) 53%, in general formula (3), n = 8, R ₁ = -CH ₂ CH (CH ₃ ) —27% of acid (A12-3)-, in general formula (4), X = Y = H, m = n = 8, k = 1, R ₁ = R ₂ = -CH ₂ CH (CH ₃ )-acid (A13-3) 13%, in the general formula (5), m = N = 8, k = 1, R ₁ = R ₂ = —CH ₂ CH (CH ₃ ) — The acid (A14-3) 7% mixture (A1-3) was obtained. The molar ratio of each component was measured by P-NMR.

Production Example 6 [Acid (A1-4)]
In a 3 L four-necked flask, 3 mol of polyethylene glycol (Mw = 1000) is heated and stirred at 55 ° C. 2 mol of diphosphorus pentoxide is added little by little at 55 ± 5 ° C. while keeping water out. The temperature was raised to 110 ± 5 ° C., the mixture was stirred for 3 hours, cooled after the reaction, and in the general formula (2), an acid represented by X = H, n = 20, R ₁ = —C ₂ H ₄ — (A11-4 ) 53%, in general formula (3), n = 20, R ₁ = -C ₂ H ₄ —27% acid (A12-4), in general formula (4), X = Y = H, m _{= n = 20, k = 1} , R 1 = R 2 = -C 2 H 4 - acid represented by (A13-4) 13%, in the general formula (5), m = n = 20, k = 1, A mixture (A1-4) of 7% of an acid (A14-4) represented by R ₁ = R ₂ = —C ₂ H ₄ — was obtained. The molar ratio of each component was measured by P-NMR.

Production Example 7 [Acid (A1-5)]
In a 3 L 4-neck flask, 3 mol of polyethylene glycol monostearate (general formula (11)) is heated and stirred at 55 ° C. Add 1 mol of diphosphorus pentoxide little by little at 55 ± 5 ° C. while keeping water out. The temperature was raised to 110 ± 5 ° C., the mixture was stirred for 3 hours, cooled after the reaction, and the acid represented by the following general formula (12) (A11-5) (12) 66% and the following general formula (13) (A13 -5) A 34% mixture (A1-5) was obtained.

Production Example 8
2.0 mol of methanol is added to 1.0 mol of acid (A1-1) which is a mixture of acid (A11-1) and acid (A13-1) obtained in Production Example 3, and the mixture is heated and stirred at 60 ° C. for 3 hours. The temperature was raised to 110 ° C., the mixture was stirred for 3 hours, and cooled after the reaction to obtain an ester mixture (A3-1).
The ester (A3-1) is an ester (A31-1) in which a part of the phosphoric acid group represented by the general formula (1) of the acid (A11-1) is methyl esterified, or a general formula of the acid (A13-1). This is a mixture of esters (A33-1) in which a part of the phosphoric acid group represented by (1) is methyl esterified.

Example 1 [Production of 10% 1,6-decanedicarboxylic acid / diammonium + acid (A1-1) / ethylene glycol electrolyte]
In a 3 L beaker, 1,6-decanedicarboxylic acid (0.5 mol) and ethylene glycol (8.5 mol) were mixed, and ammonia (1.0 mol) was blown with stirring, and 20% 1,6-decanedicarboxylic acid. A diammonium / ethylene glycol solution was obtained. To 50 g of the 20% 1,6-decanedicarboxylic acid / diammonium / ethylene glycol solution obtained above, 1 g of acid (A1-1) obtained in Production Example 3 and 49 g of ethylene glycol were added, and the mixture was stirred. An electrolytic solution having the composition described in 1 was obtained.
The proton partial charge of the acid calculated by the CAChe AM1 method of the acid (A11-1) which is a mixture of the acid (A1-1) is 0.286, the number average molecular weight is 620, and the AM1 of the CAChe of the acid (A13-1) The proton partial charge of the acid calculated by the method is 0.283, the number average molecular weight is 1140, and the total concentration of the acid (A1-1) in the electrolyte is 1%.

Example 2 [Production of 10% 1,6-decanedicarboxylic acid / diammonium + acid (A1-2) / ethylene glycol electrolyte]
1 g of acid (A1-2) obtained in Production Example 4 and 49 g of ethylene glycol were added to 50 g of 20% 1,6-decanedicarboxylic acid / diammonium / ethylene glycol solution obtained by the same method as in Example 1. Thereafter, the mixture was stirred to obtain an electrolytic solution having the composition shown in Table 1.
The proton partial charge of the acid calculated by the CAChe AM1 method of the acid (A11-2) which is a mixture of the acid (A1-2) is 0.286, the number average molecular weight is 450, and the CAChe AM1 method of (A12-2) The proton partial charge of the acid calculated by the following formula is 0.286, the number average molecular weight is 530, the proton partial charge of the acid calculated by the CAChe AM1 method of the acid (A13-2) is 0.283, the number average molecular weight is 800, The proton partial charge of the acid calculated by the CAChe AM1 method of A14-2) is 0.285, the number average molecular weight is 960, and the total concentration of the acid (A1-2) in the electrolyte is 1%.

Example 3 [Production of 10% 1,6-decanedicarboxylic acid / diammonium + acid (A1-3) / ethylene glycol electrolyte]
To 50 g of 20% 1,6-decanedicarboxylic acid / diammonium / ethylene glycol solution obtained in Production Example 1, 1 g of acid (A1-3) obtained in Production Example 5 and 49 g of ethylene glycol were added and stirred. An electrolytic solution having the composition shown in Table 1 was obtained.
The proton partial charge of the acid (A11-3) which is a mixture of the acid (A1-3) calculated by the CAChe AM1 method is 0.286, the number average molecular weight is 570, and the CAChe AM1 method of (A12-3) The proton partial charge of the acid calculated by the following formula is 0.286, the number average molecular weight is 640, the proton partial charge of the acid calculated by the CAChe AM1 method of the acid (A13-3) is 0.283, the number average molecular weight is 1030, The proton partial charge of the acid calculated by the CAChe AM1 method of A14-3) is 0.285, the number average molecular weight is 1190, and the total concentration of the acid (A1-2) in the electrolyte is 1%.

Example 4 [Production of 10% 1,6-decanedicarboxylic acid / diammonium + acid (A1-4) / ethylene glycol electrolyte]
To 50 g of the 20% 1,6-decanedicarboxylic acid / diammonium / ethylene glycol solution obtained in Production Example 1, 1 g of acid (A1-4) obtained in Production Example 6 and 49 g of ethylene glycol were added and stirred. An electrolytic solution having the composition shown in Table 1 was obtained.
The proton partial charge of the acid (A11-4) which is a mixture of the acid (A1-4) calculated by the CAChe AM1 method is 0.286, the number average molecular weight is 980, and the CAChe AM1 method of (A12-4) The proton partial charge of the acid calculated by the above formula is 0.286, the number average molecular weight is 1060, the proton partial charge of the acid calculated by the CAChe AM1 method of the acid (A13-4) is 0.283, the number average molecular weight is 1860, ( The proton partial charge of the acid calculated by the CAChe AM1 method of A14-4) is 0.285, the number average molecular weight is 2020, and the total concentration of the acid (A1-4) in the electrolyte is 1%.

Example 5 [Production of 10% 1,6-decanedicarboxylic acid / diammonium + acid (A1-5) / ethylene glycol electrolyte]
To 50 g of the 20% 1,6-decanedicarboxylic acid / diammonium / ethylene glycol solution obtained in Production Example 1, 1 g of acid (A1-5) obtained in Production Example 7 and 49 g of ethylene glycol were added and stirred. An electrolytic solution having the composition shown in Table 1 was obtained.
The proton partial charge of the acid calculated by the CAChe AM1 method of the acid (A11-5) which is a mixture of the acids (A1-5) is 0.286, the number average molecular weight is 720, and the AM1 of the CAChe of the acid (A13-5) The proton partial charge of the acid calculated by the method is 0.283, the number average molecular weight is 1030, and the total concentration of the acid (A1-1) in the electrolyte is 1%.

Example 6 [Production of 10% 1,6-decanedicarboxylic acid / diammonium + salt (A2-1) / ethylene glycol electrolyte]
After adding 1 g of acid (A1-1) obtained in Production Example 3 and 49 g of ethylene glycol to 50 g of 20% 1,6-decanedicarboxylic acid / diammonium / ethylene glycol solution obtained in Production Example 1, ammonia was added. Blowing was performed until the pH reached 7, and an electrolytic solution having the composition shown in Table 1 containing 1% of the salt (A2-1) was obtained.
The salt (A2-1) is a mixture of a salt (A21-1) of the acid (A11-1) and a salt (A23-1) of the acid (A13-1). The proton partial charge of the acid calculated by the CAChe AM1 method of the acid (A21-1) is 0.286, the number average molecular weight is 650, and the proton partial charge of the acid calculated by the AM1 method of the CAChe of the acid (A23-1) is The number average molecular weight is 0.283, and the total concentration of the acid (A2-1) in the electrolytic solution is 1%.

Example 7 [Production of 10% 1,6-decanedicarboxylic acid / diammonium + ester (A3-1) / ethylene glycol electrolyte]
To 50 g of the 20% 1,6-decanedicarboxylic acid / diammonium / ethylene glycol solution obtained in Production Example 1, 1 g of ester (A3-1) obtained in Production Example 8 and 49 g of ethylene glycol were added and stirred. An electrolytic solution having the composition shown in Table 1 was obtained.
The ester (A3-1) is a mixture of an ester (A31-1) of the acid (A11-1) and an ester (A33-1) of the acid (A13-1). The proton partial charge of the acid calculated by the CAChe AM1 method of the ester (A31-1) is 0.286, the number average molecular weight is 665, and the proton partial charge of the acid calculated by the CAChe AM1 method of the ester (A33-1) is The number average molecular weight is 0.283, and the total concentration of the ester (A3-1) in the electrolytic solution is 1%.

Example 8 [Production of 10% 1,6-decanedicarboxylic acid / ditriethylammonium + acid (A1-1) / ethylene glycol electrolyte]
In a 3 L beaker, 1,6-decanedicarboxylic acid (0.5 mol) and ethylene glycol (13.9 mol) were mixed, triethylamine (1.0 mol) was added with stirring, and 20% 1,6-decanedicarboxylic acid. A ditriethylammonium / ethylene glycol solution was obtained. After adding 1 g of acid (A1-1) obtained in Production Example 3 and 49 g of ethylene glycol to 50 g of the 20% 1,6-decanedicarboxylic acid / ditriethylammonium / ethylene glycol solution obtained above, the mixture was stirred and mixed. An electrolytic solution having the composition described in 1 was obtained.
The proton partial charge and number average molecular weight of the acid (A1-1) calculated by the CAChe AM1 method are the same as in Example 1, and the total concentration of the acid (A1-1) in the electrolyte is 1%. .

Example 9 [Production of 10% 1,6-decanedicarboxylic acid / ditriethylammonium + acid (A1-2) / ethylene glycol electrolyte]
To 50 g of 20% 1,6-decanedicarboxylic acid / ditriethylammonium / ethylene glycol solution obtained in the same manner as in Example 2, 1 g of acid (A1-2) obtained in Production Example 4 and 49 g of ethylene glycol were added. After that, stirring was performed to obtain an electrolytic solution having the composition shown in Table 1.
The proton partial charge and number average molecular weight of the acid (A1-2) calculated by the CAChe AM1 method are the same as in Example 2, and the total concentration of the acid (A1-2) in the electrolyte is 1%. .

Example 10 [Production of 15% ammonium benzoate + acid (A1-1) / ethylene glycol electrolyte]
In a 3 L beaker, benzoic acid (1.0 mol) and ethylene glycol (9.0 mol) were mixed, and ammonia (1.0 mol) was blown with stirring to obtain a 30% benzoic acid / ammonium / ethylene glycol solution. 1 g of the acid (A1-1) obtained in Production Example 3 and 49 g of ethylene glycol were added to 50 g of the 30% benzoic acid / ammonium / ethylene glycol solution obtained above, and the mixture was stirred and electrolyzed with the composition shown in Table 1. A liquid was obtained.
The proton partial charge and number average molecular weight of the acid (A1-1) calculated by the CAChe AM1 method are the same as in Example 1, and the total concentration of the acid (A1-1) in the electrolyte is 1%. .

Example 11 [Production of 15% ammonium benzoate + acid (A1-2) / ethylene glycol electrolyte]
1 g of acid (A1-2) obtained in Production Example 4 and 49 g of ethylene glycol were added to 50 g of 30% benzoic acid / ammonium / ethylene glycol solution obtained by the method of Example 3, and the mixture was stirred and listed in Table 1. An electrolytic solution having the composition was obtained.
The proton partial charge and number average molecular weight of the acid (A1-2) calculated by the CAChe AM1 method are the same as in Example 2, and the total concentration of the acid (A1-2) in the electrolyte is 1%. .

Example 12 [35% 1,2,3,4-tetramethylimidazolinium phthalic acid / γ-butyrolactone + acid (A1-1)]
Add 1 g of acid (A1-1) obtained in Production Example 3 and 64 g of γ-butyrolactone to 35 g of 1,2,3,4-tetramethylimidazolinium phthalate obtained in Production Example 1, and stir. Thus, an electrolytic solution having the composition shown in Table 1 was obtained.
The proton partial charge and number average molecular weight of the acid (A1-1) calculated by the CAChe AM1 method are the same as in Example 1, and the total concentration of the acid (A1-1) in the electrolyte is 1%. .

Example 13 [35% 1,2,3,4-tetramethylimidazolinium phthalic acid + acid (A1-2) / γ-butyrolactone]
Add 1 g of acid (A1-2) obtained in Production Example 4 and 64 g of γ-butyrolactone to 35 g of 1,2,3,4-tetramethylimidazolinium phthalate obtained in Production Example 1, and stir. Thus, an electrolytic solution having the composition shown in Table 1 was obtained.
The proton partial charge and number average molecular weight of the acid (A1-2) calculated by the CAChe AM1 method are the same as in Example 2, and the total concentration of the acid (A1-2) in the electrolyte is 1%. .

Example 14 [35% tetraethylammonium phthalic acid / γ-butyrolactone + acid (A1-1)]
1 g of the acid (A1-1) obtained in Production Example 3 and 64 g of γ-butyrolactone were added to 35 g of tetraethylammonium phthalic acid obtained in Production Example 2, and the electrolyte solution having the composition shown in Table 1 was stirred. Obtained.
The proton partial charge and number average molecular weight of the acid (A1-1) calculated by the CAChe AM1 method are the same as in Example 1, and the total concentration of the acid (A1-1) in the electrolyte is 1%. .

Example 15 [35% tetraethylammonium phthalic acid + acid (A1-2) / γ-butyrolactone]
1 g of acid (A1-2) obtained in Production Example 4 and 64 g of γ-butyrolactone were added to 35 g of tetraethylammonium phthalic acid obtained in Production Example 2 and stirred to obtain an electrolytic solution having the composition shown in Table 1. It was.
The proton partial charge and number average molecular weight of the acid (A1-2) calculated by the CAChe AM1 method are the same as in Example 2, and the total concentration of the acid (A1-2) in the electrolyte is 1%. .

Comparative Example 1 [Production of 10% 1,6-decanedicarboxylic acid / diammonium / ethylene glycol electrolyte]
50 g of ethylene glycol was added to 50 g of a 20% 1,6-decanedicarboxylic acid / diammonium / ethylene glycol solution obtained in the same manner as in Example 1, followed by stirring to obtain an electrolytic solution having the composition shown in Table 2. .

Comparative Example 2 [Production of (10% 1,6-decanedicarboxylic acid / diammonium + 1% polyethylene glycol) / ethylene glycol electrolyte]
1 g of polyethylene glycol (Mw = 1000) and 49 g of ethylene glycol were added to 50 g of a 20% 1,6-decanedicarboxylic acid / diammonium / ethylene glycol solution obtained in the same manner as in Example 1, followed by stirring. An electrolytic solution having the composition shown in Table 2 was obtained.
The proton partial charge of the hydroxyl group calculated by the CAChe AM1 method of polyethylene glycol (Mw = 1000) is 0.204, the number average molecular weight is 1000, and the concentration in the electrolyte is 1%.

Comparative Example 3 [Production of 10% 1,6-decanedicarboxylic acid / diammonium + 5% polyethylene glycol / ethylene glycol electrolyte]
To 50 g of a 20% 1,6-decanedicarboxylic acid / diammonium / ethylene glycol solution obtained in the same manner as in Example 1, 5 g of polyethylene glycol (Mw = 1000) and 45 g of ethylene glycol were added and stirred. An electrolytic solution having the composition shown in Table 2 was obtained.
The proton partial charge of the hydroxyl group calculated by the CAChe AM1 method of polyethylene glycol (Mw = 1000) is 0.204, the number average molecular weight is 1000, and the concentration in the electrolyte is 5%.

Comparative Example 4 [Production of 10% 1,6-decanedicarboxylic acid / diammonium + PEO acid / ethylene glycol electrolyte]
1 g of PEO acid (Mw = 1000) represented by the general formula (14) is obtained with respect to 50 g of a 20% 1,6-decanedicarboxylic acid / diammonium / ethylene glycol solution obtained by the same method as in Example 1, and ethylene glycol. After adding 49 g, the mixture was stirred to obtain an electrolyte solution having the composition shown in Table 2.
The proton partial charge of the carboxyl group calculated by CAChe AM1 method of polyethylene glycol (Mw = 1000) is 0.245, the number average molecular weight is 1000, and the concentration in the electrolyte is 1%.

Comparative Example 5 [Production of 10% 1,6-decanedicarboxylic acid / diammonium + phosphoric acid / ethylene glycol electrolyte]
1 g of phosphoric acid and 49 g of ethylene glycol were added to 50 g of a 20% 1,6-decanedicarboxylic acid / diammonium / ethylene glycol solution obtained in the same manner as in Example 1, and the mixture was stirred and stirred. An electrolyte solution having a composition was obtained.
The proton partial charge of the acid calculated by the CAChe AM1 method of phosphoric acid is 0.288, the molecular weight is 98, and the concentration in the electrolyte is 1%.

Comparative Example 6 [Production of 10% 1,6-decanedicarboxylic acid / diammonium + dimethyl phosphate / ethylene glycol electrolyte]
1 g of dimethyl phosphate and 49 g of ethylene glycol were added to 50 g of a 20% 1,6-decanedicarboxylic acid / diammonium / ethylene glycol solution obtained in the same manner as in Example 1, and the mixture was stirred and described in Table 2. An electrolytic solution having the composition was obtained.
The proton partial charge of the acid calculated by the CAChe AM1 method of dimethyl phosphate is 0.279, the molecular weight is 126, and the concentration in the electrolyte is 1%.

Comparative Example 7 [Production of 10% 1,6-decanedicarboxylic acid / ditriethylammonium / ethylene glycol electrolyte]
50 g of ethylene glycol was added to 50 g of a 20% 1,6-decanedicarboxylic acid / ditriethylammonium / ethylene glycol solution obtained by the same method as in Example 2, and the mixture was stirred and then electrolyte solution having the composition shown in Table 2 Got.

Comparative Example 8 [Production of (10% 1,6-decanedicarboxylic acid / ditriethylammonium + 1% polyethylene glycol) / ethylene glycol electrolyte]
1 g of polyethylene glycol (Mw = 1000) and 49 g of ethylene glycol were added to 50 g of a 20% 1,6-decanedicarboxylic acid / ditriethylammonium / ethylene glycol solution obtained in the same manner as in Example 2, followed by stirring. An electrolytic solution having the composition shown in Table 2 was obtained.
The proton partial charge of the hydroxyl group calculated by the CAChe AM1 method of polyethylene glycol (Mw = 1000) is 0.204, the number average molecular weight is 1000, and the concentration in the electrolyte is 1%.

Comparative Example 9
[Production of 15% ammonium benzoate / ethylene glycol electrolyte]
50 g of ethylene glycol was added to 50 g of a 30% benzoic acid / ammonium / ethylene glycol solution obtained in the same manner as in Example 3, and then stirred to obtain an electrolytic solution having the composition shown in Table 2.

Comparative Example 10
[Production of 15% ammonium benzoate / ethylene glycol electrolyte]
1 g of polyethylene glycol (Mw = 1000) and 49 g of ethylene glycol were added to 50 g of a 30% benzoic acid / ammonium / ethylene glycol solution obtained in the same manner as in Example 3, followed by stirring and the composition shown in Table 2 An electrolyte solution was obtained.
The proton partial charge of the hydroxyl group calculated by the CAChe AM1 method of polyethylene glycol (Mw = 1000) is 0.204, the number average molecular weight is 1000, and the concentration in the electrolyte is 1%.

Comparative Example 11 [35% 1,2,3,4-tetramethylimidazolinium phthalic acid / γ-butyrolactone]
65 g of γ-butyrolactone was added to 35 g of 1,2,3,4-tetramethylimidazolinium phthalate obtained in Production Example 1 and stirred to obtain an electrolytic solution having the composition shown in Table 2.

Comparative Example 12 [Production of (35% 1,2,3,4-tetramethylimidazolinium phthalic acid + 1% polyethylene glycol) / γ-butyrolactone electrolyte]
1 g of polyethylene glycol (Mw = 1000) and 64 g of γ-butyrolactone were added to 35 g of 1,2,3,4-tetramethylimidazolinium phthalate obtained in Production Example 1 and stirred. An electrolyte solution having a composition was obtained.
The proton partial charge of the hydroxyl group calculated by the CAChe AM1 method of polyethylene glycol (Mw = 1000) is 0.204, the number average molecular weight is 1000, and the concentration in the electrolyte is 1%.

Comparative Example 13 [35% tetraethylammonium phthalic acid / γ-butyrolactone]
65 g of γ-butyrolactone was added to 35 g of tetraethylammonium phthalic acid obtained in Production Example 2 and stirred to obtain an electrolytic solution having the composition shown in Table 2.

Comparative Example 14 [35% tetraethylammonium phthalic acid / γ-butyrolactone]
To 35 g of tetraethylammonium phthalic acid obtained in Production Example 2, 1 g of polyethylene glycol (Mw = 1000) and 64 g of γ-butyrolactone were added and stirred to obtain an electrolytic solution having the composition shown in Table 2.
The proton partial charge of the hydroxyl group calculated by the CAChe AM1 method of polyethylene glycol (Mw = 1000) is 0.204, the number average molecular weight is 1000, and the concentration in the electrolyte is 1%.

About Examples 1-15 and Comparative Examples 1-14, the specific conductivity and the spark voltage were measured by the following measuring methods, and the results are shown in Table 3.
Conductivity: Conductivity at 30 ° C. was measured using a conductivity meter CM-40S manufactured by Toa Denpa Kogyo Co., Ltd.
Withstand voltage: The discharge voltage of the electrolyte when a constant current method (2 mA) was loaded was measured using a 10 cm ² high-pressure chemical-etched aluminum foil. This is the withstand voltage.
Dielectric strength difference: In an electrolytic solution containing the same electrolyte, it represents the difference between the withstand voltage of an electrolytic solution to which a withstand voltage improver is added and the withstand voltage of an electrolytic solution to which no withstand voltage improver is added.
Conductivity difference: In an electrolytic solution containing the same electrolyte, it represents the difference between the electrical conductivity of an electrolytic solution to which a withstand voltage improver is added and the electrical conductivity of an electrolytic solution to which no withstand voltage improver is added.

As is clear from Table 3 (1), the electrolytic solutions of Examples 1 to 7 and Comparative Examples 2 to 6 are improved in withstand voltage as compared with the electrolytic solution of Comparative Example 1 that does not contain a withstand voltage improver. Among them, the electrolytes of Examples 1 to 7 and Comparative Examples 2 and 4 to 6 have the same addition amount of the withstand voltage improver and the same conductivity difference, but the electrolytes of Examples 1 to 7 are the same. The withstand voltage is higher. The electrolytic solution of Comparative Example 3 having an increased amount of addition with the same withstand voltage improver as the electrolytic solution of Comparative Example 2 has a higher withstand voltage compared to the electrolytic solution of Comparative Example 2, but the electrolytic solution of Examples 1-7. It is smaller than the withstand voltage, and the conductivity is remarkably lowered.
Similarly to Table 3 (1), as is clear from Tables 3 (2) to (5), the electrolytes of Examples 8 to 15 have a higher withstand voltage than the electrolytes of the comparative examples, and the electrical conductivity. The decline is small.

  If the electrolytic solution of the present invention is used in an electrolytic capacitor, it is possible to suppress a decrease in the specific conductivity of the electrolytic solution as much as possible and to increase the withstand voltage, and it is possible to reduce the size, reduce the impedance, and improve the reliability of the electrolytic capacitor. Industrial value is great.

Claims (5)

An electrolytic solution containing at least one of acid (A1) and acid (A1) salt (A2) having a proton partial charge of 0.260 to 0.290 calculated by AM1 method of quantum mechanical calculation software CAChe. Te, (A1) and (A2) comprises an oxyalkylene group, and Ri total concentration of 0.001% to 5% der in the electrolytic solution of (A1) and (A2),
The acid (A1) is a compound having a functional group represented by the following general formula (1),

The acid (A1) is at least one of an acid represented by the following general formula (2) and an ester thereof, and an acid (A11) having at least one functional group represented by the general formula (1);

[R ₁ is a linear or branched divalent hydrocarbon group having 2 to 10 saturated carbon atoms, and may be the same or different. The addition mode of —R ₁ O— may be random or block. n is a natural number of 1 to 220. X is a hydrogen atom, a straight-chain or branched monovalent hydrocarbon group having 1 to 300 carbon atoms, a hydroxyl group, a thiol group, an amino group, a carboxyl group, a carbonyl group, an ether group, or a thioether group. It may be a straight chain or branched monovalent hydrocarbon group having 1 to 300 carbon atoms. ]
An acid (A12) having at least one of an acid represented by the following general formula (3) and an ester thereof and having at least one functional group represented by the general formula (1);

[R ₁ and n are the same as those in the general formula (2). ],
An acid (A13) having at least one of the acid represented by the following general formula (4) and an ester thereof and having at least one functional group represented by the general formula (1);

[R ₁ , n and X are the same as those in the general formula (2). R ₂ is a straight or branched divalent hydrocarbon group having 2 to 10 saturated carbon atoms, and may be the same or different. -R ₂ O-addition manner may be random or block. R ₁ and R ₂ may be the same or different from each other. m is a natural number of 1 to 220. k is a natural number of 1-80. Y is a hydrogen atom, a linear or branched monovalent hydrocarbon group having 1 to 300 carbon atoms, a hydroxyl group, a thiol group, an amino group, a carboxyl group, a carbonyl group, an ether group, a thioether group It may be a monovalent hydrocarbon group having 1 to 300 saturated carbon atoms having a straight chain or having a branched chain. ]
An acid (A14) having at least one of the acid represented by the following general formula (5) and an ester thereof and having at least one functional group represented by the general formula (1);

[R ₁ , R _2, k, m and n are the same as those in the general formula (4). ]
An acid represented by the following general formula (6), an acid (A15) having at least one functional group represented by the general formula (1), and

[R ₁ , X and n are the same as those in the general formula (2). ]
Acid (A16) having at least one of the acid represented by the following general formula (7) and its ester and having at least one functional group represented by the general formula (1)

[R ₁ , X and n are the same as those in the general formula (2). At least Tanedea Rukoto electrolyte for an electrolytic capacitor, characterized in that selected from the group consisting of. In the acid (A11) ~ acid _(A16), the electrolytic solution according to claim 1 R 1, _{R 2} is at least 1-way ethylene group and a propylene group. The electrolyte solution according to claim 1 or 2 , wherein the acid (A1) or the salt (A2) of the acid (A1) has a number average molecular weight of 150 to 10,000. In salt (A2), the cationic component ammonium respect anion of an acid (A1), 1 quaternary ammonium, secondary ammonium, tertiary ammonium, and claims 1-3 is at least one selected from the group consisting of quaternary ammonium The electrolyte solution according to any one of the above. The electrolytic capacitor which consists of an electrolyte solution of any one of Claims 1-4 .