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Analytical Control of Dicarboxylic Anions in Complex Electrolytes

IP.com Disclosure Number: IPCOM000095493D
Original Publication Date: 1964-Feb-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 22K

Publishing Venue

IBM

Related People

Sankuer, RF: AUTHOR [+2]

Abstract

The quantitative analysis of dicarboxylic anion in the presence of materials having similar functional groups, such as aliphatic monocarboxylic anions and aliphatic hydroxymonocarboxylic anions, may be accomplished using colorimetric techniques. The succinate, aspartate and tartarate anions are exemplary of the dicarboxylic anion. The addition of hydroquinone in concentrated sulfuric acid to the solution containing the dicarboxylic anion at an elevated temperature causes a reaction and produces naphthazarin or the substituted naphthazarin. Where succinic acid is the dicarboxylic acid used, the reaction is as follows:

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Analytical Control of Dicarboxylic Anions in Complex Electrolytes

The quantitative analysis of dicarboxylic anion in the presence of materials having similar functional groups, such as aliphatic monocarboxylic anions and aliphatic hydroxymonocarboxylic anions, may be accomplished using colorimetric techniques. The succinate, aspartate and tartarate anions are exemplary of the dicarboxylic anion. The addition of hydroquinone in concentrated sulfuric acid to the solution containing the dicarboxylic anion at an elevated temperature causes a reaction and produces naphthazarin or the substituted naphthazarin. Where succinic acid is the dicarboxylic acid used, the reaction is as follows:

The procedure for determining the amount of dicarboxylic anion present in the solution as exemplified by the succinate anion is to first evaporate a suitable sample aliquot to dryness. There is added to the dry sample 0. 1 grams hydroquinone and 5 ml concentrated sulfuric acid. The reaction is allowed to proceed for sixty minutes at a temperature of 135 +/- 10 degrees C. The solution is agitated periodically. After this time, the sample is diluted to approximately 25 ml with water and simultaneously cooled. The pink colored naphthazarin complex is solvent extracted in a separatory funnel with approximately 20 ml benzene, filtered and washed free of the inorganic acid. The light transmission characteristic of the benzene layer is measured in a spectrophotometer, recorded and compared to...