Determination of thioacetamide and thiobenzamide using dichloramine-T

Abstract

Simple and accurate titrimetric methods for the determination of thioacetamide and thiobenzamide in partially aqueous media have been developed, based on their stoicheiometric oxidation with dichloramine-T (DCT) at room temperature. The direct titration of the thioamide with DCT involves a two-electron change, giving a carboxylic acid, ammonia and sulphur as oxidation products with p-toluenesulphonamide as the reduction product of DCT. A back-titration procedure involving the oxidation of thioacetamide to acetic acid, ammonium sulphate and sulphur by excess of DCT with a five-electron change has also been developed. The methods described are simple, rapid, reproducible and accurate. The reaction products have been identified by thin-layer and paper chromatography and colour tests.