JP2012164777A - Electrolyte for electrolytic capacitor and electrolytic capacitor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrolyte for an electrolytic capacitor which has excellent solubility, high electric conductivity and high spark voltage, and to provide an electrolytic capacitor using the electrolyte.SOLUTION: An electrolyte for an electrolytic capacitor contains a salt (B), preferably an ammonium salt (B1), of a long chain dibasic acid (A) represented by the general formula (1), or a mixture of (A) and (B), and an organic solvent (C), preferably ethylene glycol (C1). In the formula, (D) is an amide bond, (E) and (F) are bivalent hydrocarbon groups of 1-18C, and each of a plurality of (D) and (E) may be the same or different from each other, m, n each represents an integer of 0-5, and m+n=1-6.

Description

  The present invention relates to an electrolytic solution used for an electrolytic capacitor, and an electrolytic capacitor using the electrolytic solution. More specifically, the present invention relates to an intermediate / high pressure class electrolytic solution and an electrolytic capacitor using the same.

  In general electrolytic capacitors, a separator is inserted between an anode foil and a cathode foil, and a capacitor element obtained by winding is impregnated with an electrolytic solution, and then stored in a metal cylindrical case, and the opening is elastic rubber. And is manufactured by drawing the sealed part. In the case of an aluminum electrolytic capacitor, a high-purity aluminum foil is electrochemically etched to increase the surface area, and further subjected to chemical conversion treatment to form an oxide film to obtain an anode foil. On the other hand, the cathode foil is obtained by etching the aluminum foil and then stabilizing it.

  In recent years, with the space-saving and high temperature of the environment where capacitors are used, when the conductivity is high and the spark voltage is high, that is, the aluminum conversion coating of the electrode is hard to break, There is a demand for an electrolyte solution that is excellent in film repairing ability for repairing heat and has low characteristic deterioration at high temperatures.

  In particular, as an electrolytic solution for a medium to high voltage class electrolytic capacitor, an electrolytic solution using ethylene glycol containing a linear acid carboxylic acid such as azelaic acid, sebacic acid, decanedicarboxylic acid or a salt thereof as a solvent has been used so far. The performance degradation at the spark voltage and high temperature is not satisfactory.

  In contrast, an electrolytic solution using a secondary carboxylic acid (Patent Document 1), an electrolytic solution using a secondary carboxylic acid and a tertiary carboxylic acid in combination (Patent Document 2), or a longer main chain than before There has been proposed an electrolytic solution using a secondary carboxylic acid having a water content (Patent Document 3).

JP 2005-5336 A JP-A-6-275472 JP-A-9-63898

  However, although the proposed electrolytic capacitor can increase the spark voltage by controlling the structure of various carboxylic acids, it causes a decrease in conductivity, and if the electrolyte concentration is increased to increase the conductivity, the solubility is low. Therefore, satisfactory electrical conductivity cannot be obtained, and the characteristics of the electrolytic solution for electrolytic capacitors are insufficient.

  Therefore, an object of the present invention is to provide an electrolytic solution for an electrolytic capacitor that has both high conductivity and high spark voltage and is excellent in solubility, and an electrolytic capacitor using the electrolytic solution.

［式中、（Ｄ）は下式（２）または（３）で表されるアミド結合であり、（Ｅ）および（Ｆ）は炭素数１〜１８の２価の炭化水素基であり、複数ある（Ｄ）および（Ｅ）はそれぞれ同じでも異なっていてもよく、ｍ、ｎは０〜５の整数を表し、ｍ＋ｎ＝１〜６である。］

The inventors of the present invention have reached the present invention as a result of studies to achieve the above object.
That is, the present invention provides an electrolytic capacitor containing a salt (B) of a long-chain dibasic acid (A) represented by the general formula (1) or a mixture of (A) and (B) and an organic solvent (C). And an electrolytic capacitor using the electrolytic solution.

[In the formula, (D) is an amide bond represented by the following formula (2) or (3), (E) and (F) are divalent hydrocarbon groups having 1 to 18 carbon atoms, Certain (D) and (E) may be the same or different, and m and n represent an integer of 0 to 5, and m + n = 1 to 6. ]

  By using the long-chain dibasic acid of the present invention, it is excellent in solubility in the solvent used in the electrolytic solution for electrolytic capacitors, so that high conductivity can be obtained and an electrolytic solution for electrolytic capacitors that can provide a high spark voltage Can be provided.

In the present invention, the salt (B) of the long-chain dibasic acid (A) represented by the general formula (1) and the organic solvent (C), or a mixture of (A) and (B) and the organic solvent (C) are used. It is the electrolyte solution for electrolytic capacitors to contain. By using a salt (B) of a long-chain dibasic acid (A) or a mixture of (A) and (B), an electrolytic solution for an electrolytic capacitor having both high conductivity and high spark voltage and excellent solubility is obtained. Obtainable.

The long-chain dibasic acid (A) in the present invention is represented by the following general formula (1).

［式中、（Ｄ）は下式（２）または（３）で表されるアミド結合であり、（Ｅ）および（Ｆ）は炭素数１〜１８の２価の炭化水素基であり、複数ある（Ｄ）および（Ｅ）はそれぞれ同じでも異なっていてもよく、ｍ、ｎは０〜５の整数を表し、ｍ＋ｎ＝１〜６である。］

[In the formula, (D) is an amide bond represented by the following formula (2) or (3), (E) and (F) are divalent hydrocarbon groups having 1 to 18 carbon atoms, Certain (D) and (E) may be the same or different, and m and n represent an integer of 0 to 5, and m + n = 1 to 6. ]

  In formula (1), (D) is an amide bond, as already described.

In formula (1), (E) is a divalent hydrocarbon group having 1 to 18 carbon atoms, an alkylene group having 1 to 18 carbon atoms, an alkanediyl group having 1 to 18 carbon atoms, and an alkenylene having 2 to 18 carbon atoms. Groups. The alkylene group having 1 to 18 carbon atoms may be further substituted with an alkenyl group having 2 to 18 carbon atoms.

In the formula (1), the alkylene group having 1 to 18 carbon atoms in (E) is a linear alkylene group such as methylene, ethylene, propylene, butylene, hexylene, octylene, nonylene, decylene, dodecylene, hexadecylene, octadecylene, etc., 1-methyl Examples thereof include branched alkyl groups such as ethylene, 2,2-dimethylpropylene and 2-ethylhexylene, and cyclic alkyl groups such as cyclopropylene, cyclobutylene, cyclopentylene, cyclohexylene and bicyclo [2.2.2] octylene. From the viewpoint of electrical conductivity and spark voltage, the number of carbon atoms is preferably 1 to 12, and more preferably 2 to 9.

  Examples of the alkanediyl group having 1 to 18 carbon atoms in (E) in the formula (1) include ethanediyl, n-propanediyl, 2-methylethanediyl, n-butanediyl, 2-methylbutanediyl, 3-methylbutanediyl, Examples thereof include chain alkanediyl groups such as n-hexanediyl, n-nonanediyl, n-decanediyl and n-octadecandiyl, and cyclic alkanediyl groups such as cyclopentanediyl and cyclobutanediyl. From the viewpoint of electrical conductivity and spark voltage, the number of carbon atoms is preferably 1 to 12, and more preferably 2 to 9.

Examples of the alkenylene group having 2 to 18 carbon atoms in (E) in the formula (1) include vinylene, arylene, propenylene, 1-butenylene, 2-nonenylene, 1-decenylene, 2-dodecenylene, 9-octadecenylene and the like. From the viewpoint of electrical conductivity and spark voltage, the number of carbon atoms is preferably 2 to 12, and more preferably 2 to 9.

The alkenyl group having 2 to 18 carbon atoms that may be substituted with the alkylene group having 1 to 18 carbon atoms in (E) in the formula (1) is as described above.

  Preferred examples of (E) in formula (1) include methylene, ethylene, propylene, butylene, hexylene, octylene, nonylene, 2-nonenyl-1-ethylene, an alkylene group such as 2-decenyl-1-ethylene, ethane- 1,1-diyl, n-propane-1,1-diyl, 2-methylpropane-1,1-diyl, n-butane-1,1-diyl, 2-methylbutane-1,1-diyl, 3-methylbutane -1,1-diyl, n-hexane-1,1-diyl, alkanediyl groups such as n-nonane-1,1-yl, and alkenylene groups such as vinylene, allylene, propenylene, etc., in terms of conductivity and spark voltage To more preferably ethylene, propylene, butylene, hexylene, 2-nonenyl-1-ethylene, 2-decenyl-1-ethylene, n-propane 1,1-diyl, 2-methylpropane-1,1-diyl, n- butane-1,1-diyl, 2-methyl-1,1-butanediyl, 3-methyl-1,1-butanediyl.

  In formula (1), (F) is a divalent hydrocarbon group having 1 to 18 carbon atoms, as already described in (E) in formula (1).

  In formula (1), m and n represent the number of (D) and (E) constituting the long-chain dibasic acid, and at least one of m and n is 1 or more. The sum m + n is 1-6. If it exceeds 6, the molecular weight increases, and the electrical conductivity may decrease.

  The long-chain dibasic acid (A) of the present invention can be obtained, for example, by reacting an acid anhydride or dibasic acid halide with an amino acid or diamine compound.

  When an acid anhydride is used, it can be obtained by reacting an intramolecular cyclic acid anhydride with an amino acid or diamine compound at a predetermined molar ratio. When a dibasic acid halide is used, it can be obtained by reacting an amino acid or diamine compound at a predetermined molar ratio as in the case of using an acid anhydride. In this case, it is preferable to add a base in order to neutralize the by-product acid (hydrohalic acid). Examples of the base include tertiary amines such as trimethylamine and triethylamine, and aromatic nitrogen-containing heterocyclic compounds such as pyridine, 4-dimethylaminopyridine and imidazole. The amount of the base added is preferably equimolar with respect to the by-product acid.

  Specific examples of the intramolecular cyclic acid anhydride include malonic acid anhydride, succinic acid anhydride, alkenyl succinic acid anhydride, maleic acid anhydride, citraconic acid anhydride, glutaric acid anhydride and the like.

  Dibasic acid halides include malonic acid dihalide, succinic acid dihalide, glutaric acid dihalide, adipic acid dihalide, pimelic acid dihalide, suberic acid dihalide, azelaic acid dihalide, Examples include sebacic acid dihalide, 1,10-decanedicarboxylic acid dihalide, 1,12-dodecanedicarboxylic acid dihalide, 1,6-decanedicarboxylic acid dihalide, and the like. Halogen is preferably chlorine or bromine because of its availability.

The amino acid has an amino group and a carboxy group in the molecule, but preferably has one amino group and one carboxy group. Specific examples thereof include α-amino acids such as glycine, alanine, valine and leucine, oligopeptides such as glycylleucine, 6-aminohexanoic acid, 7-aminoheptanoic acid, 8-aminooctanoic acid, 9-aminononanoic acid, 10- Examples include aminodecanoic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid. Note that α-amino acids and oligopeptides include optically active substances, racemates, and the like, and both are preferably used in the present invention.

  Examples of the diamine compound include ethylenediamine, 1-methylethylenediamine, 1,3-propylenediamine, 1,4-butylenediamine, 1,6-hexanediamine, 1,12-dodecanediamine, and the like.

The reaction molar ratio may be changed depending on the target dibasic acid. For example, in the reaction of an intramolecular cyclic acid anhydride with an amino acid, m = 0, n = 1 (or m = 1, n = 0). A dibasic acid is obtained. In this case, the molar ratio is 2: 1 to 1: 2, more preferably 1.5: 1 to 1: 1.5, most preferably 1: 1. In the reaction of the dibasic acid halide with the amino acid, a dibasic acid of m = n = 1 is obtained, wherein the molar ratio is 1: 4, more preferably 1: 3, most preferably 1: 2. The same applies to the reaction between the diamine compound and the intramolecular cyclic acid anhydride.

  The reaction may use a solvent. Examples of the solvent used for the reaction include ethers such as diethyl ether, cyclopentyl methyl ether, tetrahydrofuran, alkyl halides such as chloroform and dichloromethane, N-methylformamide, N, N-dimethylformamide, N-methylacetamide, N, N-dimethylacetamide, etc. Amides such as hexamethylphosphoric triamide, 2-pyrrolidone, lactams such as N-methyl-2-pyrrolidone, nitriles such as acetonitrile, propionitrile, dimethyl sulfoxide, methyl Sulfoxides such as ethyl sulfoxide, sulfones such as dimethyl sulfone, diethyl sulfone, sulfolane, dimethyl urea, tetramethyl urea, N, N-dimethylethylene urea, N, N-dimethylpropylene urea, etc. Such as a subclass, and the like. One type of solvent may be used, or two or more types may be mixed.

  The reaction temperature is usually 0 to 200 ° C, preferably 20 to 150 ° C. At 0 ° C. or lower, the reaction is slow, and at 200 ° C. or higher, the yield of the target product decreases due to side reactions or the like.

  Preferred specific examples of the long-chain dibasic acid (A) in the present invention, long-chain dibasic acid represented by chemical formula (4) to long-chain dibasic acid represented by chemical formula (9) (A-6) is shown.

（Ａ−１）

(A-1)

（Ａ−２）

(A-2)

（Ａ−３）

(A-3)

（Ａ−４）

(A-4)

（Ａ−５）

(A-5)

（Ａ−６）

(A-6)

The addition amount of the long-chain dibasic acid (A) of the present invention is usually 20% by weight based on the total weight of the long-chain dibasic acid (A), its salt (B), and the organic solvent (C) from the viewpoint of solubility. Hereinafter, it is preferably 10% by weight or less, more preferably 5% by weight or less.

  As the salt (B) of the long-chain dibasic acid in the present invention, an ammonium salt, an amine salt, a quaternary ammonium salt, a fourth salt having the conjugate base of the long-chain dibasic acid (A) already described as an anion component. Grade amidinium salts. The ammonium salt is most preferred from the viewpoint of solubility in the electrolytic solution and influence on the electric conductivity and spark voltage.

The long-chain dibasic acid salt (B) in the present invention may use either a monoanion or a dianion as the anion component. Of the two carboxyl groups in (B), the anionized ratio is preferably 50 to 100%, more preferably 75 to 100%, and more preferably 90, from the viewpoint of influence on conductivity and spark voltage. ~ 100%.

The amine component is a cation component of an amine salt, and its conjugate base includes primary amines such as methylamine, ethylamine, and propylamine, secondary amines such as dimethylamine, diethylamine, ethylmethylamine, piperidine, pyrrolidine, morpholine, and trimethylamine. , Tertiary amines such as triethylamine, dimethylethylamine, N-methylmorpholine, N-methylpyrrolidine, 1,5-diazabicyclo [4.3.0] -5-nonene, 1,8-diazabicyclo [5.4.0]- Examples include amidine such as 7-undecene, dimethylimidazole, and 1-methylimidazole. Among these, from the viewpoint of the effect on solubility in the electrolyte, conductivity, and spark voltage, methylamine, ethylamine, dimethylamine, and ethylmethyl Amines, pyrrolidine, trimethylamine, Triethylamine, dimethylethylamine, N- methylpyrrolidine, 1,5-diazabicyclo [4.3.0] -5-nonene, dimethyl imidazole are preferred, methylamine, dimethylamine, trimethylamine, triethylamine is more preferable.

As the cation component of the quaternary ammonium salt, tetramethylammonium, tetraethylammonium, tetrabutylammonium, trimethylethylammonium, dimethylpyrrolidinium, N-methyl-N-propylpyrrolidinium, dimethylmorpholinium, 1-methyl- 1-azabicyclo [2.2.2] octanium, 1-methyl-1-azabicyclo [2.2.1] heptanium, 7,7-dimethyl-7-azabicyclo [2.2.1] heptanium, 5-azoniaspiro [ 4.4] Nonane, 5-azoniaspiro [4.5] decane, 1-methyl-1-azoniabicyclo [3.3.0] octane, 1-azoniatricyclo [3.3.3.0] undecane, etc. Among these, from the viewpoint of the effect on the solubility in the electrolyte, conductivity, and spark voltage, Luammonium, tetraethylammonium and dimethylpyrrolidinium are preferred, and tetramethylammonium is more preferred.

As the cation component of the quaternary amidinium salt, 8-methyl-1,8-diazabicyclo [5.4.0] -7-undecenium, 5-methyl-1,5-diazabicyclo [4.3.0] -5 Nonenium, 1,2,3,4-tetramethylimidazolinium, 1,3,4-trimethyl-2-ethylimidazolinium, 4-cyano-1,2,3-trimethylimidazolinium, 4-acetyl- 1,2,3-trimethylimidazolinium, 4-methoxy-1,2,3-trimethylimidazolinium, 4-hydroxymethyl-1,2,3-trimethylimidazolinium, 1,3-dimethylimidazolium, 1,3-diethylimidazolium, 1-ethyl-3-methylimidazolium, 1,2,3-trimethylimidazolium, 1,2,3,4-tetramethyl Midazolium, 4-cyano-1,2,3-trimethylimidazolium, 4-acetyl-1,2,3-trimethylimidazolium, 4-methoxy-1,2,3-trimethylimidazolium, 4-hydroxymethyl-1 2,3-trimethylimidazolium, 2,3-dimethyl-1,3-diazabicyclo [4.2.1] -2-nonenium, 2,3-dimethyl-1,3-diazabicyclo [2.2.1] -2-heptenium and the like, and from the viewpoints of solubility in the electrolyte, conductivity, and spark voltage, among these, tetramethylammonium, tetraethylammonium, dimethylpyrrolidinium, preferred quaternary amidinium Examples of the cation include 5-methyl-1,5-diazabicyclo [4.3.0] -5-nonenium, 1,2,3,4-tetramethylimidazole. Riniumu, 1,3,4-trimethyl-2-ethyl imidazolinium preferably, 1,2,3,4-tetramethyl imidazolinium more preferably.

These long-chain dibasic acid salts (B) used in the present invention may be used singly or in combination of two or more.

The amount of the organic solvent (C) that is the solvent of the electrolytic solution of the present invention is preferably 60 to 95 weights with respect to the total weight of the organic solvent (C), the long-chain dibasic acid (A) and the salt (B) thereof. %, And more preferably 70% by weight to 90% by weight.

Specific examples of the organic solvent (C) include alcohols such as ethanol, propanol, isopropanol, butanol, isobutanol, 2-butanol and tert-butanol, glycols such as ethylene glycol, propylene glycol, glycerin and diethylene glycol, N-methylformamide N, N-dimethylformamide, N-methylacetamide, N, N-dimethylacetamide, etc., amides such as hexamethylphosphoric triamide, 2-pyrrolidone, lactams such as N-methyl-2-pyrrolidone, γ-butyrolactone, δ -Lactones such as valerolactone and γ-valerolactone, dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, butylene carbonate and other carbonates, acetonitrile, Nitriles such as lopionitrile, sulfoxides such as dimethyl sulfoxide, methyl ethyl sulfoxide, sulfones such as dimethyl sulfone, diethyl sulfone, sulfolane, urea such as dimethyl urea, tetramethyl urea, N, N-dimethylethylene urea, N, N-dimethylpropylene urea And the like.

Among these, ethylene glycol, propylene glycol, and γ-butyrolactone are preferable, and ethylene glycol is particularly preferable. The organic solvent (C) may be used alone or in combination of two or more.

If necessary, the electrolyte solution of the present invention may be used in combination with other electrolytes conventionally used in electrolyte solutions for electrolytic capacitors, and various additives may be added.

Additives include inorganic acids such as boric acid, phosphoric acid and silicic acid, aromatic nitro compounds such as nitrophenol, nitrobenzoic acid and nitroanisole, polyhydric alcohols such as mannitol, xylitol, sorbitol and pentaerythritol, and one carbon atom. Organic carboxylic acid (J) which is -20, etc. are mentioned. The additive is usually added in the range of 0 to 20% by weight, preferably 0.01 to 15% by weight. An organic carboxylic acid (J) having 1 to 20 carbon atoms is preferable because it has an effect of increasing the withstand voltage of the electrolytic solution.

  Hereinafter, although an example and a comparative example explain the present invention further, the present invention is not limited to these. Hereinafter, unless otherwise specified, “%” represents “% by weight” and “parts” represents “parts by weight”.

Production Example 1
Synthesis of long-chain dibasic acid (A-1) In a 500 mL four-necked reaction vessel with a cooling tube, 23.4 parts (0.2 mol) of DL valine (manufactured by Nacalai Tesque) and glutaric anhydride (manufactured by Tokyo Chemical Industry) 22. 8 parts (0.2 mol) and 300 parts of tetrahydrofuran were charged. The reaction was allowed to proceed for 8 hours under heated reflux. The white solid precipitated after cooling was filtered off and dried to obtain 44.9 parts of white solid (yield 97%). This white solid was confirmed to be (A-1) by 1H-NMR.

Production Example 2
Synthesis of long-chain dibasic acid (A-2) In Production Example 1, 23.4 parts (0.2 mol) of DL valine (manufactured by Nacalai Tesque) and 26.2 parts (0.2 mol) of norleucine (manufactured by Tokyo Chemical Industry) Except for the above, the same operation as in Production Example 1 was carried out to obtain 47.1 parts of a white solid (yield 96%). This white solid was confirmed to be (A-2) by 1H-NMR.

Production Example 3
Synthesis of long-chain dibasic acid (A-3) In Production Example 1, 23.4 parts (0.2 mol) of DL valine (manufactured by Nacalai Tesque) was 26.2 parts of 6-aminohexanoic acid (manufactured by Tokyo Chemical Industry) ( The procedure was the same as in Production Example 1 except that the amount was changed to 0.2 mol) to obtain 46.1 parts of a white solid (yield 94%). This white solid was confirmed to be (A-3) by 1H-NMR.

Production Example 4
Synthesis of long-chain dibasic acid (A-4)
In Production Example 1, 23.4 parts (0.2 mol) of DL valine (manufactured by Nacalai Tesque) was replaced with 1,3.2 parts (0.2 mol) of 1,6-hexanediamine (manufactured by Tokyo Chemical Industry), glutaric anhydride (Tokyo) The same operation as in Production Example 1 was conducted except that 22.8 parts (0.2 mol) of Kasei Chemical Co., Ltd. were changed to 44.9 parts (0.2 mol) of 2-nonenyl succinic anhydride (manufactured by Tokyo Chemical Industry), and 103 9 parts of a white solid were obtained (92% yield). This white solid was confirmed to be (A-4) by 1H-NMR.

Production Example 5
Synthesis of long-chain dibasic acid (A-5) In a 500 mL four-necked reaction vessel with a cooling tube, 46.9 parts (0.4 mol) of DL valine (manufactured by Nacalai Tesque) and glutaryl dichloride (manufactured by Tokyo Chemical Industry) 33. 8 parts (0.2 mol), 31.6 parts (0.4 mol) of pyridine, and 300 parts of tetrahydrofuran were charged. The reaction was allowed to proceed for 8 hours under heated reflux. The white solid precipitated after cooling was filtered off, and the filtrate was concentrated to obtain 62.8 parts of a white solid (yield 95%). This white solid was confirmed to be (A-5) by 1H-NMR.

Production Example 6
Synthesis of long-chain dibasic acid (A-6) In Production Example 5, 46.9 parts (0.4 mol) of DL valine (manufactured by Nacalai Tesque) was converted to 69.7 parts of glycyl DL valine (manufactured by Tokyo Chemical Industry) (0.4 Mole), and the same operation as in Production Example 1 was performed to obtain 80 parts of white solid (yield 90%). This white solid was confirmed to be (A-6) by 1H-NMR.

Production Example 7
50 parts of ethylene glycol (C-1) and 13.1 parts of (A-1) are added to a synthetic glass container of ammonium salt (B-1) of long-chain dibasic acid (A-1), and ammonia gas is added thereto. 1.9 parts were blown. Stirring was continued for 1 hour to obtain an ethylene glycol solution of ammonium salt (B-1).

Production Example 8
Synthesis of ammonium salt (B-2) of long-chain dibasic acid (A-2) In Production Example 7, (A-1) 13.1 parts (A-2) 13.2 parts, ammonia gas 1.9 parts The same operation as in Production Example 1 was carried out except that the amount was 1.8 parts to obtain an ethylene glycol solution of an ammonium salt (B-2).

Production Example 9
Synthesis of ammonium salt (B-3) of long-chain dibasic acid (A-3) In Production Example 7, (A-1) 13.1 parts (A-3) 13.2 parts, ammonia gas 1.9 parts The same operation as in Production Example 1 was carried out except that the amount was 1.8 parts to obtain an ethylene glycol solution of an ammonium salt (B-3).

Production Example 10
Synthesis of ammonium salt (B-4) of long-chain dibasic acid (A-4) In Production Example 7, (A-1) 13.1 parts (A-4) 14.1 parts, ammonia gas 1.9 parts The procedure of Production Example 1 was repeated, except that the content was 0.9 part, to obtain an ethylene glycol solution of an ammonium salt (B-4).

Production Example 11
Synthesis of ammonium salt (B-5) of long-chain dibasic acid (A-5) In Production Example 7, (A-1) 13.1 parts (A-5) 13.6 parts, ammonia gas 1.9 parts The same operation as in Production Example 1 was carried out except that 1.4 parts was obtained to obtain an ethylene glycol solution of an ammonium salt (B-5).

Production Example 12
Synthesis of ammonium salt (B-6) of long-chain dibasic acid (A-6) In Production Example 7, 13.1 parts of (A-1) is 13.9 parts of (A-6) and 1.9 parts of ammonia gas The procedure was the same as in Production Example 1 except that the content was 1.1 parts to obtain an ethylene glycol solution of an ammonium salt (B-6).

Production Example 13
Synthesis of Triethylammonium Salt (B-7) of Long-Chain Dibasic Acid (A-1) In Production Example 7, 13.1 parts of (A-1) was 8.0 parts, and 1.9 parts of ammonia gas was triethylamine. The same operation as in Production Example 1 was carried out except that the content was 0 part to obtain an ethylene glycol solution of triethylammonium salt (B-7).

Production Example 14
Method for Producing 1,2,3,4-Tetramethylimidazolinium Methyl Carbonate Methanol Solution In a pressure vessel equipped with a stirrer, 180 parts of dimethyl carbonate (manufactured by Tokyo Chemical Industry) and 63 parts of methanol are charged, and 2,4-dimethyl is added thereto. 98 parts of imidazoline was dropped and stirred at 120 ° C. for 15 hours to obtain a methanol solution of 1,2,3,4-tetramethylimidazolinium methyl carbonate.

Production Example 15
Synthesis of 1,2,3,4-tetramethylimidazolinium salt (B-8) of long-chain dibasic acid (A-1) in methanol solution of 1,2,3,4-tetramethylimidazolinium methyl carbonate To 17.9 parts, 7.2 parts of a long-chain dibasic acid (A-1) was added to perform salt exchange. This solution was concentrated under reduced pressure at 100 ° C. using a rotary evaporator to obtain a yellow solid. Analysis by 1 H-NMR confirmed that this solid was a 1,2,3,4-tetramethylimidazolinium salt of long-chain dibasic acid (A-1). To this, 50 parts of ethylene glycol (C-1) was further added and stirred until uniform to obtain an ethylene glycol solution of 1,2,3,4-tetramethylimidazolinium salt (B-8).

Comparative production example 1
Synthesis of 2,4,7,12,15,17-hexamethyl-octadeca-7,11-diene-1,18-dicarboxylic acid (G-1) 460 parts of methanol was placed in a reaction vessel equipped with a stirrer and cooled to 5 ° C. Then, 102 parts of 3,5-dimethylcyclohexanone (manufactured by Tokyo Chemical Industry) and 10 parts of concentrated sulfuric acid were added thereto. While stirring, 80 parts of hydrogen peroxide (5%) was added dropwise so as not to exceed 5 ° C. The reaction was further stirred for 30 minutes. To this, 66 parts of 2-methyl-1,3-butadiene (manufactured by Tokyo Chemical Industry) was added. This solution was charged into another reaction vessel and cooled to -20 ° C. After substitution with nitrogen, 240 parts of iron (II) sulfate (manufactured by Wako Pure Chemical Industries, Ltd.) was added and reacted at -5 ° C or lower. After the reaction, the mixture was allowed to stand, and the upper layer was separated by a liquid separation operation, washed with water and distilled to obtain 105 parts of methyl ester (G-1) (yield 60%). The methyl ester (105 parts) was hydrolyzed to obtain 89 parts of a white solid (yield 90%). This white solid was confirmed to be (G-1) by 1H-NMR. (G-1) is a compound represented by the chemical formula (10) as follows.

Comparative production example 2
75 parts of ethylene glycol (C-1) and 13.8 parts of (G-1) are added to a synthetic glass container of ammonium salt (H-1) of compound (G-1), and 1.2 parts of ammonia gas is added thereto. Infused. Stirring was continued for 1 hour to obtain an ethylene glycol solution of ammonium salt (H-1).

Comparative production example 3
Synthesis of 3,7,12,16-hexamethyl-octadeca-7,11-diene-1,18-dicarboxylic acid (G-2) In Comparative Production Example 1, 102 parts of 3,5-dimethylcyclohexanone was replaced with 4-methylcyclohexanone. Except for 91 parts, the same operation as in Comparative Production Example 1 was performed to obtain 80 parts of a white solid (yield 90%). This white solid was confirmed to be (G-2) by 1H-NMR. (G-2) is a compound represented by the chemical formula (11) as follows.

Comparative production example 4
Ethylene glycol (C-1) 75 parts and (G-2) 13.8 parts are added to a synthetic glass container of ammonium salt (H-2) of compound (G-2), and ammonia gas 1.2 parts is added thereto. Infused. Stirring was continued for 1 hour to obtain an ethylene glycol solution of ammonium salt (H-2).

Example 1
In a glass container, 35 parts of ethylene glycol (C-1) was further added to 65 parts of the ethylene glycol solution (B-1) obtained in Production Example 7, and the mixture was stirred until it became uniform. -1) was obtained.

Examples 2-8
In Example 1, the ethylene glycol solution of (B-1) obtained in Production Example 6 was used as the ethylene glycol solution of (B-2) to (B-8) obtained in Production Examples 7 to 13 and 15. Except for the above, the same operation as in Example 1 was performed to obtain electrolytic solutions (X-2) to (X-8) of the present invention.

Example 9
To a glass container, 75 parts of ethylene glycol (C-1) and 21.8 parts of (A-1) were added, and 3.2 parts of ammonia gas was blown into the container. Stirring was continued for 1 hour to obtain an ethylene glycol solution of ammonium salt (B-1). This is designated as an electrolytic solution (X-9) of the present invention.

Example 10
In Example 9, the same operation as in Example 9 was performed except that 21.8 parts of (A-1) was 22.0 parts of (A-2) and 3.2 parts of ammonia gas was 3.0 parts, An ethylene glycol solution of ammonium salt (B-2) was obtained. This is designated as an electrolytic solution (X-10) of the present invention.

Example 11
In Example 9, the same operation as in Example 9 was performed except that 21.8 parts of (A-1) was 22.0 parts of (A-3) and 3.2 parts of ammonia gas was 3.0 parts, An ethylene glycol solution of ammonium salt (B-3) was obtained. This is designated as an electrolytic solution (X-11) of the present invention.

Example 12
In Example 9, the same operation as in Example 9 was performed except that 21.8 parts of (A-1) was changed to 23.6 parts of (A-4) and 3.2 parts of ammonia gas was changed to 1.4 parts, An ethylene glycol solution of ammonium salt (B-4) was obtained. This is designated as an electrolytic solution (X-12) of the present invention.

Example 13
In Example 9, the same operation as in Example 9 was performed except that 21.8 parts of (A-1) was changed to 22.7 parts of (A-5) and 3.2 parts of ammonia gas was changed to 2.3 parts. An ethylene glycol solution of an ammonium salt (B-5) was obtained. This is designated as an electrolytic solution (X-13) of the present invention.

Example 14
In Example 9, the same operation as in Example 9 was performed except that 21.8 parts of (A-1) was changed to 23.2 parts of (A-6) and 3.2 parts of ammonia gas was changed to 1.8 parts, An ethylene glycol solution of ammonium salt (B-6) was obtained. This is designated as an electrolytic solution (X-14) of the present invention.

Example 15
In Example 9, the same procedure as in Example 9 was performed, except that 21.8 parts of (A-1) was changed to 13.3 parts and ammonia gas of 3.2 parts was changed to 11.7 parts of triethylamine. An ethylene glycol solution of B-7) was obtained. This is designated as an electrolytic solution (X-15) of the present invention.

Example 16
In Production Example 15, 17.9 parts of methanol solution of 1,2,3,4-tetramethylimidazolinium methyl carbonate was 30.1 parts, 7.2 parts of (A-1) 11.9 parts, ethylene glycol (C-1) The same operation as in Production Example 15 was carried out except that 50 parts was changed to 75 parts to obtain an ethylene glycol solution of 1,2,3,4-tetramethylimidazolinium salt (B-8). . This is designated as an electrolytic solution (X-16) of the present invention.

Example 17
Into a glass container, 5 parts of long-chain dibasic acid (A-1) and 30 parts of ethylene glycol (C-1) were further added to 65 parts of the ethylene glycol solution (B-1) obtained in Production Example 13, and uniform. The mixture was stirred until the electrolyte solution (X-17) was obtained.

Example 18
In a glass container, 65 parts of the ethylene glycol solution (B-4) obtained in Production Example 7 was further added with 5 parts of a long-chain dibasic acid (A-4) and 30 parts of ethylene glycol (C-1). The mixture was stirred until the electrolyte solution (X-18) was obtained.

Example 19
In Production Example 7, except that 50 parts of ethylene glycol (C-1) was changed to 85 parts of γ-butyrolactone, the same operation as in Production Example 7 was performed to obtain a γ-butyrolactone solution of ammonium salt (B-1). . This is designated as an electrolytic solution (X-19) of the present invention.

Comparative Example 1
In a glass container, 10 parts of ethylene glycol (C-1) was further added to 90 parts of the ethylene glycol solution (H-1) obtained in Comparative Production Example 2, and the mixture was stirred until it became uniform. 1) was obtained.

Comparative Example 2
In a glass container, 10 parts of ethylene glycol (C-1) was further added to 90 parts of the ethylene glycol solution of (H-2) obtained in Comparative Production Example 4, and the mixture was stirred until it became uniform. 2) was obtained.

Comparative Example 3
To a glass container, 75 parts of ethylene glycol (C-1) and 23.1 parts of (G-1) were added, and 1.9 parts of ammonia gas was blown into the container. Stirring was continued for 1 hour to obtain an ethylene glycol solution of ammonium salt (H-1). This is referred to as a comparative electrolytic solution (Y-3).

The electrolytic solutions obtained in Examples 1 to 19 and Comparative Examples 1 to 3 were evaluated by the methods described below, and the results are shown in Table 1.

<Conductivity measurement>
The specific conductivity at 30 ° C. was measured using a conductivity meter M-40S manufactured by Toa Denpa Kogyo Co., Ltd.

<Conductivity change rate measurement>
After heating the electrolytic solution at 110 ° C. for 1000 hours in a heat-resistant container, the specific conductivity at 30 ° C. was measured in the same manner. The rate of change in conductivity was calculated by the following formula (1).

<Spark voltage measurement>
Using a 10 cm 2 high pressure chemical etching aluminum foil for the anode and a 10 cm 2 plain aluminum foil for the cathode, the discharge voltage of the electrolyte was measured when a constant current method (2 mA) was applied at 25 ° C.

＊電解液調製後析出したため電導度、火花電圧の測定を行わず。

* Because it was deposited after the electrolyte was prepared, the conductivity and spark voltage were not measured.

  As is apparent from Table 1, it can be seen that the electrolytes of the examples imparted higher electrical conductivity and higher spark voltage than the comparative electrolytes. Further, in the comparative electrolytic solution, in order to increase the conductivity, it is deposited even if the electrolyte concentration is increased, and it is difficult to achieve both high conductivity and high spark voltage. Furthermore, it turns out that the electrolysis solution of an Example has also suppressed the electrical conductivity fall by high temperature load rather than a comparison electrolyte solution. That is, the electrolytic solution of the present invention can achieve both high conductivity and high spark voltage and sufficiently ensure the reliability of the electrolytic capacitor.

  The electrolytic solution of the present invention is useful as a highly reliable aluminum electrolytic capacitor that achieves both high electrical conductivity and high spark voltage, and contributes to space saving and miniaturization of the surrounding environment.

Claims (4)

An electrolytic solution for an electrolytic capacitor containing a salt (B) of a long-chain dibasic acid (A) represented by the general formula (1) or a mixture of (A) and (B), and an organic solvent (C).

[In the formula, (D) is an amide bond represented by the following formula (2) or (3), (E) and (F) are divalent hydrocarbon groups having 1 to 18 carbon atoms, Certain (D) and (E) may be the same or different, and m and n represent an integer of 0 to 5, and m + n = 1 to 6. ]

  The electrolytic solution according to claim 1, wherein the salt (B) of the long-chain dibasic acid is an ammonium salt (B1).   The electrolyte solution according to claim 1 or 2, wherein the organic solvent (C) is ethylene glycol (C1). The electrolytic capacitor using the electrolyte solution of any one of Claims 1-3.