JP2006049531A - Electrolytic solution for aluminum electrolytic capacitor and aluminum electrolytic capacitor using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrolytic solution for aluminum electrolytic capacitor having its high stability and excellent initial specific conductivity characteristics. <P>SOLUTION: The electrolytic solution for aluminum electrolytic capacitor is an electrolytic solution represented by a general formula (1). The solution comprises: an electrolyte (C) consisting of monoanion (A1) of carboxylic acid (A), amidinium cation (B1), and/or monocation (B) of guanidinium cation (B2); and an organic solvent (D). wt% of the electrolyte (C) is ≥25 wt% and ≤65 wt% with respect to the weight of the electrolytic solution. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrolytic solution used for an aluminum electrolytic capacitor.

Conventionally, as an electrolytic solution for an aluminum electrolytic capacitor, a so-called amidine-based electrolytic solution (for example, Patent Document 1) using a quaternary carboxylate of a compound having an alkyl-substituted amidine group as an electrolyte is known.
JP-A-9-148196

  Patent Document 1 discloses that an amidine-based electrolyte containing a quaternary carboxylate of a compound having an alkyl-substituted amidine group as an electrolyte has a high initial specific conductivity and is stable in a high temperature range. But it's not enough.

  That is, an object of the present invention is to provide an electrolytic solution that is thermally stable and excellent in initial specific conductivity characteristics.

［式中、Ｙ₁およびＹ₂は、水酸基、アミノ基、チオール基、ホスフィノ基からなる群より選ばれる少なくとも１種の基を表す。Ｙ₁およびＹ₂は、同一であっても異なっていてもよい。Ｒ₁は、水素原子、水酸基、アミノ基、チオール基、ホスフィノ基、ハロゲン原子、ニトロ基、シアノ基、アルコキシ基、ホルミル基、ベンジル基、フェニル基、カルボニル結合を有する基、エステル結合を有する基、エーテル結合を有する基、又は、水酸基、アミノ基、カルボキシル基、チオール基、ホスフィノ基、ハロゲン原子、ニトロ基、シアノ基、アルコキシ基、ホルミル基、ベンジル基、フェニル基、カルボニル結合を有する基、エステル結合を有する基、エーテル結合を有する基を有していてもよい炭素数１〜３の飽和または不飽和の１価の炭化水素基を表す。Ｑ₁は、水酸基、アミノ基、チオール基、ホスフィノ基、ハロゲン原子、ニトロ基、シアノ基、アルコキシ基、カルボニル結合を有する基、エステル結合を有する基、エーテル結合を有する基、ホルミル基、ベンジル基、Ｃ−Ｎ＝Ｃ結合を有する官能基、又はフェニル基を有していてもよい炭素数１〜６の飽和または不飽和の２価の炭化水素基を表す。Ｑ₁の一部または全てが相互に結合して２個以上の芳香環かまたは複素環を形成してもよい。］ As a result of intensive studies to solve the above problems, the present inventors have two substituents capable of forming a hydrogen bond at the ortho position of the carboxyl group as shown in the following general formula (1) in the anion. An electrolytic solution that uses a monoanion of carboxylic acid (A), improves the degree of dissociation of carboxylic acid, and the weight percent of electrolyte (C) is 25 wt% or more and 65 wt% or less with respect to the weight of the electrolytic solution Has found that the initial specific conductivity characteristics are particularly excellent and that the rate of change in specific conductivity at high temperatures is small, leading to the present invention.
That is, the present invention comprises a monoanion (A1) of a carboxylic acid (A) represented by the following general formula (1) and a monocation (B) of an amidinium cation (B1) and / or a guanidinium cation (B2). An electrolyte solution comprising the electrolyte (C) and the organic solvent (D), wherein the weight percentage of the electrolyte (C) is 25% by weight or more and 65% by weight or less based on the weight of the electrolyte solution And an aluminum electrolytic capacitor using the electrolytic solution.

[Wherein Y ₁ and Y ₂ represent at least one group selected from the group consisting of a hydroxyl group, an amino group, a thiol group, and a phosphino group. Y ₁ and Y ₂ may be the same or different. R ₁ is a hydrogen atom, hydroxyl group, amino group, thiol group, phosphino group, halogen atom, nitro group, cyano group, alkoxy group, formyl group, benzyl group, phenyl group, group having a carbonyl bond, group having an ester bond A group having an ether bond, or a group having a hydroxyl group, amino group, carboxyl group, thiol group, phosphino group, halogen atom, nitro group, cyano group, alkoxy group, formyl group, benzyl group, phenyl group, carbonyl bond, A saturated or unsaturated monovalent hydrocarbon group having 1 to 3 carbon atoms which may have a group having an ester bond or a group having an ether bond. Q ₁ is a hydroxyl group, amino group, thiol group, phosphino group, halogen atom, nitro group, cyano group, alkoxy group, group having a carbonyl bond, group having an ester bond, group having an ether bond, formyl group, benzyl group , A functional group having a C—N═C bond, or a saturated or unsaturated divalent hydrocarbon group having 1 to 6 carbon atoms which may have a phenyl group. Part or all of Q ₁ may be bonded to each other to form two or more aromatic rings or heterocyclic rings. ]

  The electrolytic solution for an aluminum electrolytic capacitor of the present invention can provide an electrolytic solution that is thermally stable, that is, has a high specific conductivity even when used at high temperatures and is excellent in initial specific conductivity characteristics.

  The electrolyte solution of the present invention comprises a monoanion (A1) of the carboxylic acid (A) represented by the general formula (1) and a monocation (B1) of the amidinium cation (B1) and / or guanidinium cation (B2). An electrolyte solution consisting of an electrolyte (C) and an organic solvent (D), wherein the weight percentage of the electrolyte (C) is 25% by weight or more, preferably 30% by weight or more based on the weight% of the electrolyte solution 65% by weight or less, preferably 55% by weight or less, more preferably 45% by weight or less. When the weight percentage of the electrolyte (C) is less than 25 weight%, the specific conductivity is lowered by decreasing the ion concentration in the electrolyte, and when the weight percentage of the electrolyte (C) is greater than 65 weight%, the viscosity of the electrolyte As the value increases, the ion mobility decreases and the specific conductivity decreases.

［式中、Ａ₁は水素原子、水酸基、アミノ基、ニトロ基、シアノ基、カルボキシル基、チオール基、ハロゲン原子、アルコキシ基、エステル結合を有する基、エーテル結合を有する基、カルボニル結合を有する基、又は、水酸基、アミノ基、ニトロ基、シアノ基、カルボキシル基、チオール基、ハロゲン原子、アルコキシ基、エステル結合を有する基、エーテル結合を有する基、カルボニル結合を有する基を有していてもよい炭素数１〜２０の１価の炭化水素基を表す。
Ａ₂とＡ₃はそれぞれ、水酸基、アミノ基、ニトロ基、シアノ基、カルボキシル基、チオール基、ハロゲン基、アルコキシ基、エステル結合を有する基、エーテル結合を有する基、カルボニル結合を有する基、又は、水酸基、アミノ基、ニトロ基、シアノ基、カルボキシル基、チオール基、ハロゲン基、アルコキシ基、エステル結合を有する基、エーテル結合を有する基、カルボニル結合を有する基を有していてもよい炭素数１〜２０の１価の炭化水素基を表す。
Ｑ₂は炭素数１〜５の炭化水素基、水酸基、アミノ基、ニトロ基、シアノ基、カルボキシル基、チオール基、ハロゲン原子、アルコキシ基、エステル結合を有する基、エーテル結合を有する基、カルボニル結合を有する基を有していてもよい炭素数２〜１０のアルキレン基、アリーレン基もしくはアルケニレン基を表す。Ａ₁、Ａ₂、Ａ₃およびＱ₂の一部または全てが相互に結合して環を形成しても良い。］
上記の方法のうち、電解質（Ｃ）の純度の観点から（２）が好ましい。 A known method is used as a method for producing the electrolyte (C) of the present invention, and is not particularly limited, but the following method is preferable.
(1) For example, the method described in Japanese Patent No. 2972709. That is, the production method of obtaining (C) by quaternizing amidine and / or guanidine and performing acid exchange.
(2) For example, the method described in Japanese Patent No. 2964244. That is, the following general formula (2) obtained by once hydrolyzing each amidinium cation (B1) and / or guanidinium cation (B2) obtained by quaternizing amidine and / or guanidine or A process for obtaining (C) by reacting the disubstituted diamine monoamide compound (E) represented by (3) with a carboxylic acid (A).

[Wherein, A ₁ is a hydrogen atom, a hydroxyl group, an amino group, a nitro group, a cyano group, a carboxyl group, a thiol group, a halogen atom, an alkoxy group, a group having an ester bond, a group having an ether bond, or a group having a carbonyl bond. Or a hydroxyl group, an amino group, a nitro group, a cyano group, a carboxyl group, a thiol group, a halogen atom, an alkoxy group, a group having an ester bond, a group having an ether bond, or a group having a carbonyl bond. Represents a monovalent hydrocarbon group having 1 to 20 carbon atoms.
A ₂ and A ₃ are each a hydroxyl group, an amino group, a nitro group, a cyano group, a carboxyl group, a thiol group, a halogen group, an alkoxy group, a group having an ester bond, a group having an ether bond, a group having a carbonyl bond, or , A hydroxyl group, an amino group, a nitro group, a cyano group, a carboxyl group, a thiol group, a halogen group, an alkoxy group, a group having an ester bond, a group having an ether bond, or a group having a carbonyl bond 1-20 monovalent hydrocarbon groups are represented.
Q ₂ is a hydrocarbon group having 1 to 5 carbon atoms, hydroxyl group, amino group, nitro group, cyano group, carboxyl group, thiol group, halogen atom, alkoxy group, group having an ester bond, group having an ether bond, carbonyl bond Represents an alkylene group having 2 to 10 carbon atoms, an arylene group or an alkenylene group which may have a group having A part or all of A ₁ , A ₂ , A ₃ and Q ₂ may be bonded to each other to form a ring. ]
Among the above methods, (2) is preferable from the viewpoint of the purity of the electrolyte (C).

  In the electrolyte (C) of the present invention, the purity of the electrolyte can be increased to 99.5% or more by using the production method (2). An electrolytic solution having an electrolyte purity of 99.5% or more is more preferable because the specific conductivity can be further improved as compared with a normal electrolytic solution having a low purity.

［式中、Ｙ₁およびＹ₂は、上記一般式（１）と同じである。Ｒ₂及びＲ₃は上記Ｒ₁と同じである。Ｒ₁，Ｒ₂およびＲ₃は、同一であっても異なっていてもよい。］
芳香族カルボン酸の例としては、下記のものが挙げられる。
γーレゾルシル酸、２，４，６−トリヒドロキシ安息香酸、２，６−ジヒドロキシ−４−フルオロ安息香酸、２，６−ジヒドロキシ−４−クロロ安息香酸、２，６−ジヒドロキシ−４−ブロモ安息香酸、２，６−ジヒドロキシ−４−ニトロ安息香酸、２，６−ジヒドロキシ−４−シアノ安息香酸、ペンタヒドロキシ安息香酸、２，６−ジアミノ安息香酸、２，４，６−トリアミノ安息香酸、２，６−ジアミノ−４−フルオロ安息香酸、２，６−ジアミノ−４−クロロ安息香酸、２，６−ジアミノ−４−ブロモ安息香酸、２，６−ジアミノ−４−ニトロ安息香酸、２，６−ジアミノ−４−シアノ安息香酸、ペンタアミノ安息香酸、２，６−ジチオ安息香酸、２，４，６−トリチオ安息香酸、２，６−ジチオ−４−フルオロ安息香酸、２，６−ジチオ−４−クロロ安息香酸、２，６−ジチオ−４−ブロモ安息香酸、２，６−ジチオ−４−ニトロ安息香酸、２，６−ジチオ−４−シアノ安息香酸、ペンタチオ安息香酸など。
複素環を有するカルボン酸としては、下記のものが挙げられる。
２，４−ジヒドロキシ−３−ピリジンカルボン酸、３，５−ジヒドロキシ−４−ピリジンカルボン酸、２，４−ジアミノ−３−ピリジンカルボン酸、３，５−ジアミノ−４−ピリジンカルボン酸、２，５−ジヒドロキシ−３，４−フランジカルボン酸、２，４−ジヒドロキシ−３−フランカルボン酸、２，５−ジアミノ−３，４−フランジカルボン酸など。 Examples of the carboxylic acid (A) include aromatic carboxylic acids and carboxylic acids having a heterocyclic ring.
As the aromatic carboxylic acid, a compound represented by the following general formula (4) is preferable.

[Wherein Y ₁ and Y ₂ are the same as those in the general formula (1). R ₂ and R ₃ are the same as R ₁ described above. R ₁ , R ₂ and R ₃ may be the same or different. ]
The following are mentioned as an example of aromatic carboxylic acid.
γ-resorcylic acid, 2,4,6-trihydroxybenzoic acid, 2,6-dihydroxy-4-fluorobenzoic acid, 2,6-dihydroxy-4-chlorobenzoic acid, 2,6-dihydroxy-4-bromobenzoic acid 2,6-dihydroxy-4-nitrobenzoic acid, 2,6-dihydroxy-4-cyanobenzoic acid, pentahydroxybenzoic acid, 2,6-diaminobenzoic acid, 2,4,6-triaminobenzoic acid, 2, 6-diamino-4-fluorobenzoic acid, 2,6-diamino-4-chlorobenzoic acid, 2,6-diamino-4-bromobenzoic acid, 2,6-diamino-4-nitrobenzoic acid, 2,6- Diamino-4-cyanobenzoic acid, pentaaminobenzoic acid, 2,6-dithiobenzoic acid, 2,4,6-trithiobenzoic acid, 2,6-dithio-4-fluorobenzoic acid, 2,6-di O-4-chlorobenzoic acid, 2,6-dithio-4-bromobenzoic acid, 2,6-dithio-4-nitrobenzoic acid, 2,6-dithio-4-cyanobenzoic acid, such as Pentachio benzoate.
The following are mentioned as carboxylic acid which has a heterocyclic ring.
2,4-dihydroxy-3-pyridinecarboxylic acid, 3,5-dihydroxy-4-pyridinecarboxylic acid, 2,4-diamino-3-pyridinecarboxylic acid, 3,5-diamino-4-pyridinecarboxylic acid, 2, 5-dihydroxy-3,4-furandicarboxylic acid, 2,4-dihydroxy-3-furancarboxylic acid, 2,5-diamino-3,4-furandicarboxylic acid and the like.

The carboxylic acid (A) may be used alone or in combination of two or more.
Among the carboxylic acids (A), preferably γ-resorcylic acid, 2,4,6-trihydroxybenzoic acid, 2,6-dihydroxy-4-nitrobenzoic acid, 2,6-diaminobenzoic acid, 2, 4,6-triaminobenzoic acid, 2,6-diamino-4-nitrobenzoic acid, 2,4-dihydroxy-3-pyridinecarboxylic acid, 3,5-dihydroxy-4-pyridinecarboxylic acid, more preferably γ-resorcylic acid, 2,6-diaminobenzoic acid, and 2,4-dihydroxy-3-pyridinecarboxylic acid.

Examples of the monocation (B) include an amidinium cation (B1) and a guanidinium cation (B2).
Examples of the amidinium cation (B1) include the following.
[1] Imidazolinium 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-trimethyl Imidazolinium, 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-1 , 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] 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 Hydropyrimidinium, 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.

[3] Dihydropyrimidinium 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.
Of the above (B1), imidazoliniums are preferable from the viewpoint of initial conductivity.

Examples of the guanidinium cation (B2) include the following.
[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-tetraethylimidazolinium, 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 -Tetrahydro-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-dimethyl Amino-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 Linium, 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 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-tetraethyl-1,4,5,6-tetrahydropyrimidinium, 2-dimethylamino-1,3-dimethyl-1,4,5,6-teto Hydropyrimidinium, 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 4-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- Tetrahydropyrimidinium, 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-tetrahydropyrimidi Dinium, 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.

[3] 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 Tetraethyl-1,4 (6) -dihydropyrimidinium, 2-dimethylamino-1,3-dimethyl-1,4 (6) -dihydropyrimidinium, 2-diethylamino-1 3-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-cyanomethy -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)- Dihydropyrimidinium, 2-dimethylamino-3-methoxymethyl-1-methyl-1,4 (6) -dihydropyrimidinium, 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-hydroxy Ethyl-1-methyl-1,4,5,6-tetrahydropyrimidinium, 2-dimethylamino-4-hydroxymethyl-1,3-dimethyl-1,4 (6) -dihydropyrimidinium, and the like.
Of the above (B2), guanidiniums having an imidazolinium skeleton are preferable from the viewpoint of initial conductivity.

In addition, the said cation (B) may use together 1 type, or 2 or more types.
Of the cations (B), 1,2,3,4-tetramethylimidazolinium cation, 1-ethyl-2,3-dimethylimidazolinium cation, 2-dimethylamino-1,3,4 -Trimethylimidazolinium, more preferably 1,2,3,4-tetramethylimidazolinium cation, 1-ethyl-2,3-dimethylimidazolinium cation.

Specific examples of the organic solvent (D) in the electrolytic solution are as follows.
(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, diethylene glycol, Xylene glycol, etc.), trihydric alcohol (glycerin, etc.), tetravalent or higher alcohol (hexitol, etc.)
(2) Ethers 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, α-acetyl-γ-butyrolactone, β-butyrolactone, γ-valerolactone, δ-valerolactone, etc .;
(6) Nitriles Acetonitrile, propionitrile, butyronitrile, acrylonitrile, methacrylonitrile, benzonitrile, etc .;
(7) Carbonates Ethylene carbonate, propion carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, etc .;
(8) Sulfoxides Dimethyl sulfoxide, sulfolane, 3-methyl sulfolane, 2,4-dimethyl sulfolane, etc .;
(9) Ketone solvents:
Acetone, methyl ethyl ketone, diethyl ketone, acetophenone, cyclohexanone, cyclopentanone, etc.
(10) Other organic solvents 1,3-dimethyl-2-imidazolidinone, N-methylpyrrolidone, aromatic solvents (toluene, xylene, etc.) paraffinic solvents (normal paraffin, isoparaffin, etc.), etc .;

  Two or more organic solvents (D) can be used in combination. Among these, preferred is a solvent mainly composed of at least one selected from the group consisting of lactones, ethers and sulfoxides, and more preferably selected from the group consisting of γ-butyrolactone, sulfolane and ethylene glycol. A solvent mainly comprising at least one kind, and most preferably a solvent mainly containing γ-butyrolactone. The content of lactones and γ-butyrolactone in (D) is preferably 50 to 100% by weight, more preferably 80 to 100% by weight.

  From the viewpoint of the initial specific conductivity of the electrolytic solution, the organic solvent may contain water. In the case of using water, the content of water is preferably 10% by weight or less, more preferably 7% by weight or less, particularly preferably 5% by weight or less based on the weight of the electrolytic solution from the viewpoint of corrosion of the capacitor. From the viewpoint of the initial specific conductivity, 0.1% by weight or more is preferable, and 1% by weight or more is more preferable.

  The electrolytic solution of the present invention contains the electrolyte (C) as an essential component, but may contain other commonly used electrolytes.

  The chlorine ion, sulfate ion, iron ion, copper ion, lead ion, sodium ion, and potassium ion contained in the electrolytic solution of the present invention are each preferably 10 ppm or less from the viewpoint of corrosion of the capacitor with respect to the weight of the electrolytic solution. More preferably, it is 5 ppm or less, and particularly preferably 1 ppm or less.

  If necessary, various additives usually used in the electrolytic solution can be added to the electrolytic solution of the present invention. Examples of the additive include phosphoric acid derivatives (for example, phosphoric acid, phosphoric acid ester, 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. The total addition amount is preferably 20% by weight or less, more preferably 0.01 to 10% by weight with respect to the electrolyte (C) from the viewpoint of electrical conductivity and solubility in the electrolytic solution.

  The electrolytic solution in the present invention is used for an electrolytic capacitor element. The electrolytic capacitor element is not particularly limited. For example, in a wound aluminum electrolytic capacitor, a capacitor element formed by winding an aluminum oxide foil and a cathode aluminum foil on the surface with a separator interposed therebetween. This element may be impregnated with the electrolytic solution of the present invention as a driving electrolytic solution, and after the capacitor element is accommodated in, for example, a bottomed cylindrical aluminum case, the opening of the aluminum case is sealed. An aluminum electrolytic capacitor can be formed by sealing with an agent.

  Next, specific examples of the present invention will be described, but the present invention is not limited thereto.

2,4-Dimethylimidazoline was dropped into a methanol solution of dimethyl carbonate to carry out a quaternization reaction. By adding γ-resorcylic acid (1 mol) to the produced 1,2,3,4-tetramethylimidazolinium methyl carbonate salt (1 mol), and performing methanol removal and dehydration reaction, 1,2,3, 4-tetramethylimidazolinium .gamma.-resorcylic acid monoanion salt (C-1) was obtained.
Γ-Butyrolactone was added to (C-1) to obtain an electrolytic solution in which the weight percentage of (C-1) was 35% by weight with respect to the weight of the electrolytic solution.

  Γ-Butyrolactone was added to (C-1) to obtain an electrolytic solution in which the weight percentage of (C-1) was 25% by weight with respect to the weight of the electrolytic solution.

  Γ-Butyrolactone was added to (C-1) to obtain an electrolytic solution in which the weight percentage of (C-1) was 65% by weight with respect to the weight of the electrolytic solution.

2,4-Dimethylimidazoline was dropped into a methanol solution of dimethyl carbonate to carry out a quaternization reaction. The produced 1,2,3,4-tetramethylimidazolinium methyl carbonate salt was hydrolyzed with water to obtain a monoamidoamine and purified by distillation. The purity of the purified monoamidoamine was 99.9%. By adding γ-resorcylic acid (1 mol) to purified monoamidoamine (1 mol) and carrying out dehydration cyclization reaction, 1,2,3,4-tetramethylimidazolinium · γ-resorcylic acid monoanion salt ( C-2) was obtained.
Γ-Butyrolactone was added to (C-2) to obtain an electrolytic solution in which the weight percentage of (C-2) was 35% by weight with respect to the weight of the electrolytic solution.

  Γ-Butyrolactone was added to (C-2) to obtain an electrolytic solution in which the weight percentage of (C-2) was 25% by weight with respect to the weight of the electrolytic solution.

  Γ-Butyrolactone was added to (C-2) to obtain an electrolytic solution in which the weight percentage of (C-2) was 65% by weight with respect to the weight of the electrolytic solution.

  Γ-Butyrolactone and water were added to (C-1) to obtain an electrolytic solution in which the weight percentage of (C-1) was 35% by weight and the weight percentage of water was 5% by weight with respect to the weight of the electrolytic solution. .

  Γ-Butyrolactone and water were added to (C-1) to obtain an electrolytic solution in which the weight percentage of (C-1) was 25% by weight and the weight percentage of water was 5% by weight with respect to the weight of the electrolytic solution. .

  Γ-Butyrolactone and water were added to (C-1) to obtain an electrolytic solution in which the weight percentage of (C-1) was 65% by weight and the weight percentage of water was 5% by weight with respect to the weight of the electrolytic solution. .

  Γ-Butyrolactone and water were added to (C-2) to obtain an electrolytic solution in which the weight percentage of (C-2) was 35% by weight and the weight percentage of water was 5% by weight with respect to the weight of the electrolytic solution. .

  Γ-Butyrolactone and water were added to (C-2) to obtain an electrolytic solution in which the weight percentage of (C-2) was 25% by weight and the weight percentage of water was 5% by weight with respect to the weight of the electrolytic solution. .

  Γ-Butyrolactone and water were added to (C-2) to obtain an electrolytic solution in which the weight percentage of (C-2) was 65% by weight and the weight percentage of water was 5% by weight with respect to the weight of the electrolytic solution. .

2,4-Dimethylimidazoline was dropped into a methanol solution of dimethyl carbonate to carry out a quaternization reaction. By adding 2,6-diaminobenzoic acid (1 mol) to the resulting 1,2,3,4-tetramethylimidazolinium methyl carbonate salt (1 mol), and performing methanol removal and dehydration reaction, 1,2 , 3,4-tetramethylimidazolinium 2,6-diaminobenzoic acid monoanion salt (C-3) was obtained.
Γ-Butyrolactone was added to (C-3) to obtain an electrolytic solution in which the weight percentage of (C-3) was 35% by weight with respect to the weight of the electrolytic solution.

  Γ-butyrolactone was added to (C-3) to obtain an electrolytic solution in which the weight percentage of (C-3) was 25% by weight with respect to the weight of the electrolytic solution.

  Γ-Butyrolactone was added to (C-3) to obtain an electrolytic solution in which the weight percentage of (C-3) was 65% by weight with respect to the weight of the electrolytic solution.

<Comparative Example 1>
Γ-Butyrolactone was added to (C-1) to obtain an electrolytic solution in which the weight percentage of (C-1) was 20% by weight with respect to the weight of the electrolytic solution.

<Comparative example 2>
Γ-Butyrolactone was added to (C-1) to obtain an electrolytic solution in which the weight percentage of (C-1) was 70% by weight with respect to the weight of the electrolytic solution.

<Comparative Example 3>
2,4-Dimethylimidazoline was dropped into a methanol solution of dimethyl carbonate to carry out a quaternization reaction. The resulting 1,2,3,4-tetramethylimidazolinium methyl carbonate salt was hydrolyzed with water and the monoamidoamine was purified by distillation. The purity of the purified monoamidoamine was 99.9%. By adding phthalic acid (1 mol) to purified monoamidoamine (1 mol) and carrying out dehydration cyclization reaction, 1,2,3,4-tetramethylimidazolinium phthalate monoanion salt (C-4) )
Γ-Butyrolactone was added to (C-4) to obtain an electrolytic solution in which the weight percentage of (C-4) was 20% by weight with respect to the weight of the electrolytic solution.

  With respect to the electrolyte solutions of Examples 1 to 15 and Comparative Examples 1 to 3 of the present invention, the initial specific conductivity at 30 ° C. and the specific conductivity due to thermal transformation were measured by the following methods, and the results are shown in Table 1. .

<Initial specific conductivity>
The initial specific conductivity (initial K30) at 30 ° C. of the electrolytic solution is the specific conductivity measured at 30 ° C., and the better the low impedance characteristic, the higher the initial K30. The higher the initial K30, the better the initial specific conductivity characteristics. Using a specific conductivity measuring device [product name (CM-40S), manufacturer name (Toa Denpa Kogyo Co., Ltd.)] as a measuring instrument, the temperature of the measurement cell charged with the electrolyte is adjusted to 30 ° C. to increase the specific conductivity. It was measured.

<Specific conductivity by thermal transformation>
The specific conductivity at 30 ° C. after the electrolyte solution was subjected to a heat resistance test at 125 ° C. × 100 hours, 500 hours, and 1000 hours in a sealed SUS ampule was measured by the same measurement method as the initial specific conductivity.

  As is clear from Table 1, the electrolyte solutions of Examples 1 to 15 of the present invention are excellent in the initial specific conductivity characteristics as compared with Comparative Examples 1 to 3, and are also excellent in the specific conductivity after the heat resistance test.

The electrolytic solution for an aluminum electrolytic capacitor of the present invention can provide an electrolytic solution that is thermally stable and excellent in initial specific conductivity characteristics. In view of the above effects, if the electrolytic solution of the present invention is used for an electrolytic solution for an aluminum electrolytic capacitor, the resistance can be reduced and the performance of the aluminum electrolytic capacitor can be improved. Therefore, the market value is great.

Claims (10)

An electrolyte (C) comprising a monoanion (A1) of a carboxylic acid (A) represented by the following general formula (1) and a monocation (B) of an amidinium cation (B1) and / or a guanidinium cation (B2) And an electrolytic solution comprising an organic solvent (D), wherein the weight percentage of the electrolyte (C) is 25 wt% or more and 65 wt% or less with respect to the weight of the electrolyte Electrolyte.

[Wherein Y ₁ and Y ₂ represent at least one group selected from the group consisting of a hydroxyl group, an amino group, a thiol group, and a phosphino group. Y ₁ and Y ₂ may be the same or different. R ₁ is a hydrogen atom, hydroxyl group, amino group, thiol group, phosphino group, halogen atom, nitro group, cyano group, alkoxy group, formyl group, benzyl group, phenyl group, group having a carbonyl bond, group having an ester bond A group having an ether bond, or a group having a hydroxyl group, amino group, carboxyl group, thiol group, phosphino group, halogen atom, nitro group, cyano group, alkoxy group, formyl group, benzyl group, phenyl group, carbonyl bond, A saturated or unsaturated monovalent hydrocarbon group having 1 to 3 carbon atoms which may have a group having an ester bond or a group having an ether bond. Q ₁ is a hydroxyl group, amino group, thiol group, phosphino group, halogen atom, nitro group, cyano group, alkoxy group, group having a carbonyl bond, group having an ester bond, group having an ether bond, formyl group, benzyl group , A functional group having a C—N═C bond, or a saturated or unsaturated divalent hydrocarbon group having 1 to 6 carbon atoms which may have a phenyl group. Part or all of Q ₁ may be bonded to each other to form two or more aromatic rings or heterocyclic rings. ] The electrolyte (C) is obtained by reacting a carboxylic acid (A) with a disubstituted diamine monoamide compound (E) represented by the following general formula (2) or (3). Electrolyte.

[Wherein, A ₁ is a hydrogen atom, a hydroxyl group, an amino group, a nitro group, a cyano group, a carboxyl group, a thiol group, a halogen atom, an alkoxy group, a group having an ester bond, a group having an ether bond, or a group having a carbonyl bond. Or a hydroxyl group, an amino group, a nitro group, a cyano group, a carboxyl group, a thiol group, a halogen atom, an alkoxy group, a group having an ester bond, a group having an ether bond, or a group having a carbonyl bond. Represents a monovalent hydrocarbon group having 1 to 20 carbon atoms.
A ₂ and A ₃ are each a hydroxyl group, an amino group, a nitro group, a cyano group, a carboxyl group, a thiol group, a halogen group, an alkoxy group, a group having an ester bond, a group having an ether bond, a group having a carbonyl bond, or , A hydroxyl group, an amino group, a nitro group, a cyano group, a carboxyl group, a thiol group, a halogen group, an alkoxy group, a group having an ester bond, a group having an ether bond, or a group having a carbonyl bond 1-20 monovalent hydrocarbon groups are represented.
Q ₂ is a hydrocarbon group having 1 to 5 carbon atoms, hydroxyl group, amino group, nitro group, cyano group, carboxyl group, thiol group, halogen atom, alkoxy group, group having an ester bond, group having an ether bond, carbonyl bond Represents an alkylene group having 2 to 10 carbon atoms, an arylene group or an alkenylene group which may have a group having A part or all of A ₁ , A ₂ , A ₃ and Q ₂ may be bonded to each other to form a ring. ] 3. The electrolytic solution according to claim 1, wherein water contained in the electrolytic solution is 0.1 wt% or more and 10 wt% or less. The electrolytic solution according to any one of claims 1 to 3, wherein the carboxylic acid (A) is a compound represented by the general formula (4).

[Wherein Y ₁ and Y ₂ are the same as those in the general formula (1). R ₂ and R ₃ are the same as R ₁ described above. R ₁ , R ₂ and R ₃ may be the same or different. ] The electrolysis according to claim 4, wherein R ₁ , R ₂ and R ₃ are at least one group selected from the group consisting of a hydrogen atom, a methyl group, a hydroxyl group, an amino group, a carboxyl group, a thiol group, and a phosphino group. liquid. The electrolyte solution according to any one of claims 1 to 5, wherein the carboxylic acid (A) is selected from the group consisting of γ-resorcylic acid, 2,6-diaminobenzoic acid, and 2,4-dihydroxy-3-pyridinecarboxylic acid. The electrolyte (C) is 1,2,3,4-tetramethylimidazolinium · γ-resorsylate and / or 1-ethyl-2,3-dimethylimidazolinium · γ-resorsylate. The electrolyte solution in any one of Claims 1-6. The electrolytic solution according to any one of claims 1 to 7, wherein the organic solvent (D) is a solvent mainly comprising at least one selected from the group consisting of γ-butyrolactone, sulfolane, and ethylene glycol. The chlorine ion, sulfate ion, iron ion, copper ion, lead ion, sodium ion, and potassium ion contained in the electrolytic solution are each 10 ppm or less with respect to the weight of the electrolytic solution. Electrolyte. An aluminum electrolytic capacitor comprising the electrolytic solution according to any one of claims 1 to 9 as the electrolytic solution.