Tetraoxalyl derivatives of some diamines suggested as secondary standards in permanganometric titrations

ABSTRACT

The reaction between urea, thiourea and p-phenylene diamine with aliphatic diprotic acids depends upon the molar ratio of the reactants and the experimental conditions employed. At a 1 4 molar ratio [diamine oxalic acid] under reflux condition, the tetrafunctional compounds are obtained. IR, UV and 1HNMR-spectroscopic studies were carried out for structure elucidation and characterization. Thermogravimetric analysis of the investigated compounds showed that 4 molecules of water of crystallization per each molecule of ligand were present. These ligands fulfill the requirements of ideal secondary standards for potassium permanganate. Alternatively, standardized potassium permanganate solutions are used for the volumetric microdetermination of as low as 0.1 mg of each of these ligands