Abstract
The reactions of metal ions with various carboxylic acids including EDTA were investigated in DMF using the polarographic method. It was found that most of the metal ions form slightly soluble salts with EDTA before the formation of corresponding chelates ; alkali metal ions react with EDTA in the ratio of 4 : 1, alkaline earth metal ions and other bivalent cations in the ratio of 4 : 2, and trivalent cations such as iron and indium ions in the ratio of 4 : 3. Most of the metal complexes of EDTA formed in DMF were found to be more stable than those in aqueous solutions. Therefore, in 100% DMF these complexes, except complexes of iron (III), copper (II), rubidium (I) and cesium (I), showed no polarograpnic wave until the solvent was reduced. The behaviour of EDTA complexes in DMF were compared with that of the complexes formed with other carboxylic acids, such as oxalic, malonic, succinic, phthalic, acetic, benzoic and salicylic acids.
