Thallimetric Oxidations. Part III. Determination of glyoxylic acid and binary mixtures of glyoxylic, oxalic and formic acids by photochemical methods

Abstract

Glyoxylic acid is oxidised photochemically to carbon dioxide and water by thallium(III) in the presence of Bras catalyst. Based on this, a convenient photochemical redox method is described for the determination of glyoxylic acid by titrating the thallium(I) formed bromimetrically in 1.5–2.0 M hydrochloric acid in the presence of Methyl Orange as indicator. Based on the fact that the photochemical oxidations of glyoxylic acid, oxalic acid and formic acid proceed differently in the presence of Br^–, Cl^– and Mn²⁺ and in combination, methods are described for the analysis of binary mixtures of these acids by titrating the thallium(I) formed under different conditions.