Longer life electrolytic capacitors and electrolyte therefor

An electrolytic capacitor particularly useful for operation in the 300-600 VDC operating range, said capacitor comprising anode and cathode members consisting of aluminum separated by a paper insulating spacer impregnated with an electrolyte consisting essentially of a solution containing, as a major ingredient, at least one glycol of 2-4 carbons, 1.00-12.00 wt. % of water, 0.10-5.00 wt. % of an unsaturated aliphatic dicarboxylic acid of 16-36 carbons, 0.00-4.00 wt. % of an aliphatic diene monocarboxylic acid of 5-9 carbons, 0.00-10.0 wt. % of a monohydric aliphatic alcohol of 6-12 atoms, 0.00-10.00 wt. % of dodecanedioic acid, 0.00-0.10 wt. % of phosphoric acid, 0.00-5.0 of a nitro aromatic compound having a benzene ring-substituted nitro moiety and a dialkylamine wherein each alkyl is of 1-4 carbons in an amount sufficient to provide a pH of 7.0-8.5.