Electrolyte solution for driving electrolytic capacitor and electrolytic capacitor

Abstract

An electrolyte solution for driving an electrolytic capacitor having a solvent composed of 20 to 80 wt % of an organic solvent and 80 to 20 wt % of water, characterized in that it comprises one or more nitro compounds or nitroso compounds exclusive of nitrophenol, nitrobenzoic acid, dinitrobenzoic acid, nitroacetophenone and nitroanisole; an electrolytic capacitor comprising the electrolyte solution for driving an electrolytic capacitor; and an electrolytic capacitor comprising one or more nitro compounds or nitroso compounds located at another portion than an electrolyte solution therein. The electrolyte solution preferably contains a carboxylic acid or a salt thereof or an inorganic acid or a salt thereof as an electrolyte. The electrolytic capacitor exhibits a low impedance, excellent low temperature stability and good life characteristics, and further, is excellent in the effect to absorb a hydrogen gas, even when use is made of an electrolyte solution employing mixed solvent having a great water content and when an electrolytic capacitor is used under a high temperature condition.

1 . An electrolytic solution, for driving an electrolytic capacitor, comprising a solvent consisting of from 20 to 80 wt % of an organic solvent and from 80 to 20 wt % of water, which contains one or more nitro or nitroso compound except for nitrophenol, nitrobenzoic acid, dinitrobenzoic acid, nitroacetophenone and nitroanisole.  
     
     
         2 . The electrolytic solution for driving an electrolytic capacitor according to  claim 1 , wherein the nitro or nitroso compound is soluble in water, a polar solvent or a protonic polar organic solvent.  
     
     
         3 . The electrolytic solution for driving an electrolytic capacitor according to  claim 1 , which comprises at least one electrolyte selected from the group consisting of a carboxylic acid or a salt thereof, and an inorganic acid or a salt thereof.  
     
     
         4 . The electrolytic solution for driving an electrolytic capacitor according to  claim 1 , wherein the nitro or nitroso compound is aminonitroanisole, aminonitrotoluene, aminonitropyridine, aminonitrophenol, aminonitrophenolsulfonic acid, aminonitrobenzenesulfonic acid, aminonitrobenzothiazole, aminonitrobenzotrifluoride, aminonitrobenzonitrile, nitrophenyl isocyanate, isonitr6soacetophenone, N-ethyl-2-(l-ethyl-2-hydroxy-2-nitrosohydrazino)-ethanamine, O-ethyl-O-(p-nitrophenyl)thionobenzene, ethylnitrobenzene, ethyl-2-(hydroxyimino)-5-nitro-3-hexeneamide, octanitrobenzoylsaccharose, nitrophenyloctyl ether, nitrophenyl galactopyranoside, 3-carboxy-4-nitrophenyl disulfide, bisnitrobenzylfluorescein, glycerol carbonatenitrobenzene sulfonate, glutamyl nitroanilide, nitrophenyl acetate, nitrobenzylidene acetate, diaminonitrobenzene, dithiobisnitrobenzoic acid, dithiobisnitropyridine, dinitroaniline, dinitroquinoxaline-2,3-dione, dinitrosalicylic acid, dinitrodiphenylamine, dinitrodiphenylsulfone, dinitronaphtholsulfonic acid, dinitrobibenzyl, dinitrophenylaniline, dinitrophenylhydrazine, dinitrophenol, dinitrophthalic acid, dinitrofluorenone, dinitrofluorobenzene, dinitrobenzaldehyde, dinitrobenzoylmethylbenzylamine, dinitrobenzophenone, nitroaminothiazole, dimethylnitroaniline, dimethylnitrophenylphosphorothioate, dimethoxynitrobenzyl alcohol, bisdinitrophenyl oxalate, succinimidyl nitrophenylacetate, tetranitrophenyl porphyrin, trinitrophenol, trinitrobenzenesulfonic acid, nitroacetanilide, nitroazobenzenediol, nitroanisidine, nitroaniline, nitroanilinesulfonic acid, nitroaminoanisole, nitroaminotoluene, nitroaminophenol, nitroarginine, ethyl nitrobenzoate, methyl nitrobenzoate, nitroanthranilic acid, nitroanthranilonitrile, nitroisatin, nitroimidazole, nitroindazole, 2-nitroindan-1,3-dione, nitroindole, nitrouracil, nitroethanol, nitroethylbenzene, nitrocatechol, nitroquipazinemaleic acid, nitrocresol, nitrocinnamic acid, nitrosalicylic acid, nitrodiazoaminoazobenzene, nitrodiaminobenzene, nitrodiphenylamine, nitrodimethylaniline, nitrosulfonazo III, nitrothiophene, nitrotyrosine, nitroterephthalic acid, nitrotoluidine, nitrotoluic acid, nitropicoline, nitrohydroxyaniline, nitrobiphenyl, nitropiperonal, nitropyridinol, nitrobarbituric acid, nitrophenylacetonitrile, nitrophenylazoorcinol, nitrophenylazonaphthol, nitrophenylazomethylresorcinol, nitrophenylaniline, nitrophenyloctyl ether, nitrophenylgalactopyranoside, nitrophenylxylopyranoside, nitrophenylglucuronide, nitrophenylglucopyranoside, nitrophenylacetic acid, nitrophenyldodecyl ether, nitrophenylarsonic acid, nitrophenylhydrazine, nitrophenylphenylazophenyl triazene, nitrophenylphenyl ether, nitrophenylmaltopentaoside, nitrophenylmannopyranoside, nitrophenylbutyric acid, diethyl nitrophenylphosphate, nitrophenylenediamine, nitrophenethole, nitrophenolarsonic acid, nitrophenolmethyl ether, nitrophthalimide, nitrophthalic acid, nitrohumic acid, nitropropionic acid, nitroveratryl alcohol, nitrobenzylamine, nitrobenzyl alcohol, nitrobenzyldiisopropylisourea, nitrobenzylpyridine, nitrobenzamide, nitrobenzimidazole, nitrobenzohydrazide, nitrobenzeneazoorcinol, nitrobenzeneazonaphthol, nitromethane, nitroethane, nitrobenzeneazoresorcinol, nitrobenzenesulfonic acid, nitrobenzocoumarin, nitrobenzonitrile, nitrobenzophenone, nitromesitylene, nitromethoxyaniline, bisnitrophenyl disulfide, bisnitrophenylsulfone, bismethylthionitroethene, hydroxynitrobenzoic acid, hydroxynitrotoluene, hydroxynitropyridine, hydroxynitrophenylarsonic acid, hydroxynitrobenzaldehyde, 3-[2-hydroxy-1-(1-methylethyl)-2-nitrosohydrazino]-1-propanonamine, phenylnitroaniline, 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide, fluoronitroacetanilide, fluoronitroaniline, fluoronitrophenylazide, fluoronitrophenol, methylnitroaniline, methylnitrophenol, methylnitropyridine, methylnitropyridine oxide, methoxynitroaniline, methoxynitrobenzoic acid, methoxynitrophenol, methoxybenzylaminonitrobenzofurazan, nitrophenyl butyrate, nitronium tetrafluoroborate, nitrophenyl phosphate, nitrosoacetylpenicillamine, nitroso(acetoxymethyl)methylamine, nitroso oxine, nitrosoquinolinol, nitrosoglutathione, nitrosodiisobutylamine, nitrosodiethylamine, nitrosodiethylaniline, nitrosodisulfonic acid, nitrosodiphenylamine, nitrosodimethylamine, nitrosonaphthol, nitrosonaphtholdisulfonic acid, nitrosohydroxyquinoline, nitrosophenylaniline, nitrosophenylhydroxylamine ammonium, nitrosophenol, N-[(N-nitrosomethylamino)methyl]benzamide, 2,2′-(hydroxynitrosohydrazono)bisethanamine, N-methyl-2-(1-ethyl-2-hydroxy-2-nitrosohydrazino)-ethanamine, N,N′-dinitroso-p-phenylenediamine, N,N′-dinitrosopentamethylenetetramine, dimethylnitrosoaniline, dimethylnitrosoamine, nitrosonium tetrafluoroborate, N-[N′-methyl-N′-nitroso(aminomethyl)]benzamide, N-methyl-N-nitroso-p-toluenesulfonamide, nitrobenzene, dinitrobenzene, dinitrotoluene, nitronaphthalene, dinitronaphthalene, dinitrobiphenyl, dimethylnitrotoluene, dinitropyrene, nitrobenzoic acid ester, dimethylnitrobenzene, nitroanthracene, nitroisoquinoline, nitroxylene, ethyl nitroacetate, nitrocyclopentane, nitrostyrene, nitropyrrole, nitrofurazone, nitrofuraldehyde, nitrohexane, nitrobenzaldehyde, nitrolignin, 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide, nitroacrylamide, fluoronitrotoluene, fluoronitrobenzene, fluoronitrodiphenyl ether, trinitroacetonitrile, trinitroaniline, trinitrobenzoic acid, trinitroethane, trinitroxylene, trinitrotoluene, trinitronaphthalene, trinitrofluorenone, trinitrobenzene, trinitromesitylene, trinitromethane, trinitroresorcinol, dinitroacetanilide, dinitroanisole, dinitroanthraquinone, dinitroethane, dinitroethanediamine, dinitrocarbanilide, dinitroxylene, dinitroglycerol, dinitrocresol, dinitronaphthol, dinitrophenyl, dinitrophenylhydrazone, dinitromethane, dinitroresorcinol, nitroamide, nitroanthraquinone, nitroisophthalic acid, nitroethylene, ethyl nitrocarbamate, nitroquinaldic acid, nitroguanidine, nitroglycol, nitroglycerin, nitrodimethylamine, nitrocamphor, methylnitropropane, nitrosulfathiazole, nitrocellulose, nitrosomethane, nitrosoguanidine, nitrosodimethylaniline, nitrosotoluene, nitrosodisulfonic acid, nitrosopiperidine, nitrosobenzene, nitrosomethylurea, nitronaphthylamine, nitronaphthol, nitropyridine, nitrophenanthrene, nitrophenylpropiolic acid, nitrophenetidine, nitrophenolsulfonic acid, nitropentane, nitroresorcinol, nitrourea, trinitroxylenol, trinitrodiphenyl ether, trinitrotriazidobenzene, trinitrophloroglucinol, nitroacridine, nitroacridone, nitroacetone, nitroanilic acid, nitroaminoacetic acid, nitroisatin, nitroisobutane, nitroindene, nitrourethane, nitrocarbostyril, nitrodiglycol, nitro-p-cymene, nitrocinnamaldehyde, N-nitrosoacetanilide, nitrosoanisidine, nitrosoaniline, nitrosobenzoic acid, nitrosoanthranilic acid, nitrosocatechol, nitrosocarvacrol, nitrosocresol, nitrosonaphthylamine, nitrothioanisole, nitrothiophenol, nitronaphthalenesulfonic acid, nitronaphthylamine, nitronaphthoic acid, nitronitrosobenzene, nitrohydroquinone, nitropyrogallol, nitrophenanthridine, nitrophenanthroline, nitrophenylurethane, nitrophenylurea, nitrobutane, nitrophthalide, nitrofuran, nitropropylene, nitrophloroglucinol, nitrobenzanilide, nitrobenzaldoxime, nitrobenzoylformic acid, nitrobenzimidazole, nitromalonic acid, nitromalondialdehyde, nitromandelic acid, nitromannitol, nitromethylnaphthalene, nitromalic acid, nitroresorcinol, nitron, nitrosoresorcinol, aminonitropyrimidine, trinitrofluorenylidene malononitrile, nitrofluoranthene, nitrobenzocrown, fluoronitrobenzofurazan, methylnitronitrosoguanidine, methylnitronitrophenylpyrazolone, nitrofluorene, nitropropane, nitropropoxyaniline, trinitroanisole, trinitrocresol, trinitrobenzaldehyde, nitrodiethylaniline, nitrostilbene, nitrosonaphthalene, nitrosobenzaldehyde, nitrosomethylurethane, nitrophenylhydrazone, dinitrotartaric acid, dinitrostilbene, dinitrosoresorcinol, dinitrohydroquinone, dinitroresorcinol, nitroquinoline, dinitrosophenol, trinitrosophenol, dinitrosobenzoic acid, trinitrosobenzoic acid, dinitroacetophenone, trinitroacetophenone, nitrosoacetophenone, dinitrosoacetophenone, trinitrosoacetophenone, nitrosoanisole, dinitrosoanisole, trinitrosoanisole or an isomer, salt, derivative, coordinate bonded form or clathrate form thereof.  
     
     
         5 . The electrolytic solution for driving an electrolytic capacitor according to  claim 1 , wherein the nitro or nitroso compounds are used in combination of two or more thereof.  
     
     
         6 . The electrolytic solution for driving an electrolytic capacitor according to  claim 1 , wherein the nitro or nitroso compound is contained in an amount of 0.01 to 5 wt % based on the entire amount of the electrolytic solution.  
     
     
         7 . The electrolytic solution for driving an electrolytic capacitor according to  claim 6 , which additionally contains from 0.01 to 10% of a salt or derivative of nitrophenol, nitrobenzoic acid, dinitrobenzoic acid, nitroacetophenone and nitroanisole.  
     
     
         8 . The electrolytic solution for driving an electrolytic capacitor according to  claim 1 , wherein the organic solvent is a protonic solvent, an aprotic solvent or a mixture thereof.  
     
     
         9 . The electrolytic solution for driving an electrolytic capacitor according to  claim 3 , wherein the carboxylic acid or a salt thereof is selected from the group consisting of a monocarboxylic acid, a dicarboxylic acid, a tricarboxylic acid, a saturated carboxylic acid and an unsaturated carboxylic acid, represented by formic acid, acetic acid, propionic acid, butyric acid, p-nitrobenzoic acid, salicylic acid, benzoic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, fumaric acid, maleic acid, phthalic acid, azelaic acid, citric acid and hydroxybutyric acid, derivatives thereof, and their ammonium salts, sodium salts, potassium salts, amine salts and alkylammonium salts.  
     
     
         10 . The electrolytic solution for driving an electrolytic capacitor according to  claim 3 , wherein the carboxylic acid or a salt thereof is selected from the group consisting of a formic acid, an acetic acid, a p-nitrobenzoic acid, a salicylic acid, an oxalic acid, a malonic acid, a fumaric acid, a maleic acid, a phthalic acid, a citric acid, a sulfamic acid, an ethylenediaminetetraacetic acid, and their ammonium salts, sodium salts, potassium salts, amine salts and alkylammonium salts.  
     
     
         11 . The electrolytic solution for driving an electrolytic capacitor according to  claim 3 , wherein the carboxylic acid or a salt thereof is a formic acid.  
     
     
         12 . The electrolytic solution for driving an electrolytic capacitor according to  claim 3 , wherein the inorganic acid or a salt thereof is selected from the group consisting of an inorganic acid represented by phosphoric acid, phosphorous acid, hypophosphorous acid, boric acid, sulfamic acid and alkylphosphoric acid, an inorganic acid having a carbon chain such as alkyl group, and their ammonium salts, sodium salts, potassium salts, amine salts and alkylammonium salts.  
     
     
         13 . The electrolytic solution for driving an electrolytic capacitor according to  claim 3 , which comprises a combination of the carboxylic acid or a salt thereof and at least oneinorganic acid selected from a phosphoric acid, a phosphorous acid, a boric acid, a hypophosphorous acid, a sulfamic acid and an alkylphosphoric acid.  
     
     
         14 . The electrolytic solution for driving an electrolytic capacitor according to  claim 1 , which further comprises at least one compound selected from the group consisting of (1) a chelate compound, (2) saccharides, (3) a hydroxybenzyl alcohol and(or) an L-glutamic-diacetic acid or a salt thereof and (4) a gluconic acid and(or) a gluconic lactone.  
     
     
         15 . The electrolytic solution for driving an electrolytic capacitor according to  claim 1 , wherein the solvent consists of 20 to 55 wt % of an organic solvent and 80 to 45 wt % of water.  
     
     
         16 . The electrolytic solution for driving an electrolytic capacitor according to  claim 15 , wherein the solvent consists of 20 to 35 wt % of an organic solvent and 80 to. 65 wt % of water.  
     
     
         17 . The electrolytic solution for driving an electrolytic capacitor according to  claim 1 , wherein the specific resistance of the electrolytic solution is 68 Ωcm or less.  
     
     
         18 . The electrolytic solution for driving an electrolytic capacitor according to  claim 1 , wherein the specific resistance of the electrolytic solution is 40 Ωcm or less.  
     
     
         19 . The electrolytic solution for driving an electrolytic capacitor according to  claim 1 , wherein the specific resistance of the electrolytic solution is 30 Ωcm or less.  
     
     
         20 . An electrolytic capacitor comprising the electrolytic solution for driving an electrolytic capacitor according to  claim 1 .  
     
     
         21 . An electrolytic capacitor using an electrolytic solution constituted by a solvent consisting of from 20 to 80 wt % of an organic solvent and from 80 to 20 wt % of water, the electrolytic capacitor comprising a nitro or nitroso compound except for nitrophenol, nitrobenzoic acid, dinitrobenzoic acid, nitrophenone and nitroanisole, in a portion inside the capacitor other than in the electrolytic solution.  
     
     
         22 . The electrolytic capacitor according to  claim 21 , wherein the nitro or nitroso compound is aminonitroanisole, aminonitrotoluene, aminonitropyridine, aminonitrophenol, aminonitrophenolsulfonic acid, aminonitrobenzenesulfonic acid, aminonitrobenzothiazole, aminonitrobenzotrifluoride, aminonitrobenzonitrile, nitrophenyl isocyanate, isonitrosoacetophenone, N-ethyl-2-(1-ethyl-2-hydroxy-2-nitrosohydrazino)-ethanamine, O-ethyl-O-(p-nitrophenyl)thionobenzene, ethylnitrobenzene, ethyl-2-(hydroxyimino)-5-nitro-3-hexeneamide, octanitrobenzoylsaccharose, nitrophenyloctyl ether, nitrophenyl galactopyranoside, 3-carboxy-4-nitrophenyl disulfide, bisnitrobenzylfluorescein, glycerol carbonatenitrobenzene sulfonate, glutamyl nitroanilide, nitrophenyl acetate, nitrobenzylidene acetate, diaminonitrobenzene, dithiobisnitrobenzoic acid, dithiobisnitropyridine, dinitroaniline, dinitroquinoxaline-2,3-dione, dinitrosalicylic acid, dinitrodiphenylamine, dinitrodiphenylsulfone, dinitronaphtholsulfonic acid, dinitrobibenzyl, dinitrophenylaniline, dinitrophenylhydrazine, dinitrophenol, dinitrophthalic acid, dinitrofluorenone, dinitrofluorobenzene, dinitrobenzaldehyde, dinitrobenzoylmethylbenzylamine, dinitrobenzophenone, nitroaminothiazole, dimethylnitroaniline, dimethylnitrophenylphosphorothioate, dimethoxynitrobenzyl alcohol, bisdinitrophenyl oxalate, succinimidyl nitrophenylacetate, tetranitrophenyl porphyrin, trinitrophenol, trinitrobenzenesulfonic acid, nitroacetanilide, nitroazobenzenediol, nitroanisidine, nitroaniline, nitroanilinesulfonic acid, nitroaminoanisole, nitroaminotoluene, nitroaminophenol, nitroarginine, ethyl nitrobenzoate, methyl nitrobenzoate, nitroanthranilic acid, nitroanthranilonitrile, nitroisatin, nitroimidazole, nitroindazole, 2-nitroindan-1,3-dione, nitroindole, nitrouracil, nitroethanol, nitroethylbenzene, nitrocatechol, nitroquipazinemaleic acid, nitrocresol, nitrocinnamic acid, nitrosalicylic acid, nitrodiazoaminoazobenzene, nitrodiaminobenzene, nitrodiphenylamine, nitrodimethylaniline, nitrosulfonazo III, nitrothiophene, nitrotyrosine, nitroterephthalic acid, nitrotoluidine, nitrotoluic acid, nitropicoline, nitrohydroxyaniline, nitrobiphenyl, nitropiperonal, nitropyridinol, nitrobarbituric acid, nitrophenylacetonitrile, nitrophenylazoorcinol, nitrophenylazonaphthol, nitrophenylazomethylresorcinol, nitrophenylaniline, nitrophenyloctyl ether, nitrophenylgalactopyranoside, nitrophenylxylopyranoside, nitrophenylglucuronide, nitrophenylglucopyranoside, nitrophenylacetic acid, nitrophenyldodecyl ether, nitrophenylarsonic acid, nitrophenylhydrazine, nitrophenylphenylazophenyl triazene, nitrophenylphenyl ether, nitrophenylmaltopentaoside, nitrophenylmannopyranoside, nitrophenylbutyric acid, diethyl nitrophenylphosphate, nitrophenylenediamine, nitrophenethole, nitrophenolarsonic acid, nitrophenolmethyl ether, nitrophthalimide, nitrophthalic acid, nitrohumic acid, nitropropionic acid, nitroveratryl alcohol, nitrobenzylamine, nitrobenzyl alcohol, nitrobenzyldiisopropylisourea, nitrobenzylpyridine, nitrobenzamide, nitrobenzimidazole, nitrobenzohydrazide, nitrobenzeneazoorcinol, nitrobenzeneazonaphthol, nitromethane, nitroethane, nitrobenzeneazoresorcinol, nitrobenzenesulfonic acid, nitrobenzocoumarin, nitrobenzonitrile, nitrobenzophenone, nitromesitylene, nitromethoxyaniline, bisnitrophenyl disulfide, bisnitrophenylsulfone, bismethylthionitroethene, hydroxynitrobenzoic acid, hydroxynitrotoluene, hydroxynitropyridine, hydroxynitrophenylarsonic acid, hydroxynitrobenzaldehyde, 3-[2-hydroxy-1-(1-methylethyl)-2-nitrosohydrazino]-1-propanonamine, phenylnitroaniline, 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide, fluoronitroacetanilide, fluoronitroaniline, fluoronitrophenylazide, fluoronitrophenol, methylnitroaniline, methylnitrophenol, methylnitropyridine, methylnitropyridine oxide, methoxynitroaniline,. methoxynitrobenzoic acid, methoxynitrophenol, methoxybenzylaminonitrobenzofurazan, nitrophenyl butyrate, nitronium tetrafluoroborate, nitrophenyl phosphate, nitrosoacetylpenicillamine, nitroso(acetoxymethyl)methylamine, nitroso oxine, nitrosoquinolinol, nitrosoglutathione, nitrosodiisobutylamine, nitrosodiethylamine, nitrosodiethylaniline, nitrosodisulfonic acid, nitrosodiphenylamine, nitrosodimethylamine, nitrosonaphthol, nitrosonaphtholdisulfonic acid, nitrosohydroxyquinoline, nitrosophenylaniline, nitrosophenylhydroxylamine ammonium, nitrosophenol, N-[(N-nitrosomethylamino)methyl]benzamide, 2,2′-(hydroxynitrosohydrazono)bisethanamine, N-methyl-2-(1-ethyl-2-hydroxy-2-nitrosohydrazino)-ethanamine, N,N′-dinitroso-p-phenylenediamine, N,N′-dinitrosopentamethylenetetramine, dimethylnitrosoaniline, dimethylnitrosoamine, nitrosonium tetrafluoroborate, N-[N′-methyl-N′-nitroso(aminomethyl)]benzamide, N-methyl-N-nitroso-p-toluenesulfonamide, nitrophenol, nitrobenzoic acid, dinitrobenzoic acid, nitroacetophenone, nitroanisole, nitrobenzene, dinitrobenzene, dinitrotoluene, nitronaphthalene, dinitronaphthalene, dinitrobiphenyl, dimethylnitrotoluene, dinitropyrene, nitrobenzoic acid ester, dimethylnitrobenzene, nitroanthracene, nitroisoquinoline, nitroxylene, ethyl nitroacetate, nitrocyclopentane, nitrostyrene, nitropyrrole, nitrofurazone, nitrofuraldehyde, nitrohexane, nitrobenzaldehyde, nitrolignin, 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide, nitroacrylamide, fluoronitrotoluene, fluoronitrobenzene, fluoronitrodiphenyl ether, trinitroacetonitrile, trinitroaniline, trinitrobenzoic acid, trinitroethane, trinitroxylene, trinitrotoluene, trinitronaphthalene, trinitrofluorenone, trinitrobenzene, trinitromesitylene, trinitromethane, trinitroresorcinol, dinitroacetanilide, dinitroanisole, dinitroanthraquinone, dinitroethane, dinitroethanediamine, dinitrocarbanilide, dinitroxylene, dinitroglycerol, dinitrocresol, dinitronaphthol, dinitrophenyl, dinitrophenylhydrazone, dinitromethane, dinitroresorcinol, nitroamide, nitroanthraquinone, nitroisophthalic acid, nitroethylene, ethyl nitrocarbamate, nitroquinaldic acid, nitroguanidine, nitroglycol, nitroglycerin, nitrodimethylamine, nitrocamphor, methylnitropropane, nitrosulfathiazole, nitrocellulose, nitrosomethane, nitrosoguanidine, nitrosodimethylaniline, nitrosotoluene, nitrosodisulfonic acid, nitrosopiperidine, nitrosobenzene, nitrosomethylurea, nitronaphthylamine, nitronaphthol, nitropyridine, nitrophenanthrene, nitrophenylpropiolic acid, nitrophenetidine, nitrophenolsulfonic acid, nitropentane, nitroresorcinol, nitrourea, trinitroxylenol, trinitrodiphenyl. ether, trinitrotriazidobenzene, trinitrophloroglucinol, nitroacridine, nitroacridone, nitroacetone, nitroanilic acid, nitroaminoacetic acid, nitroisatin, nitroisobutane, nitroindene, nitrourethane, nitrocarbostyril, nitrodiglycol, nitro-p-cymene, nitrocinnamaldehyde, N-nitrosoacetanilide, nitrosoanisidine, nitrosoaniline, nitrosobenzoic acid, nitrosoanthranilic acid, nitrosocatechol, nitrosocarvacrol, nitrosocresol, nitrosonaphthylamine, nitrothioanisole, nitrothiophenol, nitronaphthalenesulfonic acid, nitronaphthylamine, nitronaphthoic acid, nitronitrosobenzene, nitrohydroquinone, nitropyrogallol, nitrophenanthridine, nitrophenanthroline, nitrophenylurethane, nitrophenylurea, nitrobutane, nitrophthalide, nitrofuran, nitropropylene, nitrophloroglucinol, nitrobenzanilide, nitrobenzaldoxime, nitrobenzoylformic acid, nitrobenzimidazole, nitromalonic acid, nitromalondialdehyde, nitromandelic acid, nitromannitol, nitromethylnaphthalene, nitromalic acid, nitroresorcinol, nitron, nitrosoresorcinol, aminonitropyrimidine, trinitrofluorenylidene malononitrile, nitrofluoranthene, nitrobenzocrown, fluoronitrobenzofurazan, methylnitronitrosoguanidine, methylnitronitrophenylpyrazolone, nitrofluorene, nitropropane, nitropropoxyaniline, trinitroanisole, trinitrocresol, trinitrobenzaldehyde, nitrodiethylaniline, nitrostilbene, nitrosonaphthalene, nitrosobenzaldehyde, nitrosomethylurethane, nitrophenylhydrazone, dinitrotartaric acid, dinitrostilbene, dinitrosoresorcinol, dinitrohydroquinone, dinitroresorcinol, nitroquinoline, dinitrosophenol, trinitrosophenol, dinitrosobenzoic acid, trinitrosobenzoic acid, dinitroacetophenone, trinitroacetophenone, nitrosoacetophenone, dinitrosoacetophenone, trinitrosoacetophenone, nitrosoanisole, dinitrosoanisole, trinitrosoanisole or an isomer, salt, derivative, coordinate bonded form or clathrate form thereof.  
     
     
         23 . The electrolytic capacitor according to  claim 21 , which comprises the nitro or nitroso compound or an isomer, salt or derivative thereof on the electrode surface.  
     
     
         24 . The electrolytic capacitor according to  claim 21 , wherein the nitro or nitroso compound or an isomer, salt or derivative thereof is attached or impregnated to the electrode surface by the coating or by the dipping in a solution having dissolved therein the nitro or nitroso compound or an isomer, salt or derivative thereof.  
     
     
         25 . The electrolytic capacitor according to  claim 21 , wherein the nitro or nitroso compound or an isomer, salt or derivative thereof is contained in a separator constituting the electrolytic capacitor.  
     
     
         26 . The electrolytic capacitor according to  claim 21 , wherein the nitro or nitroso compound or an isomer, salt or derivative thereof is attached or dipped to the separator by coating or by dipping in a solution having dissolved therein the nitro or nitroso compound or an isomer, salt or derivative thereof.  
     
     
         27 . The electrolytic capacitor according to  claim 21 , wherein the amount of the nitro or nitroso compound set forth in  claim 22  or an isomer, salt or derivative thereof contained in the electrode foil is from 0.007 to 1 mg/cm 2  (projectional area).  
     
     
         28 . The electrolytic capacitor according to  claim 21 , wherein the amount of the nitro or nitroso compound or an isomer, salt or derivative thereof contained in the separator is from 0.007 to 1 mg/cm 2  (projectional area).  
     
     
         29 . The electrolytic capacitor according to  claim 21 , wherein the solvent consists of from 20 to 55 wt % of an organic solvent and from 80 to 45 wt % of water.  
     
     
         30 . The electrolytic capacitor according to  claim 29 , wherein the solvent consists of from 20 to 35 wt % of an organic solvent and from 80 to 65 wt % of water.