The reaction of Se(IV) with 2-aminodiphenylamine and its application to spectrophotometric determination of selenium in a strongly acidic medium

Se(IV) reacts with 2-aminodiphenylamine in perchloric, sulphuric or hydrochloric acid media to give the phenylbenzoselen-adiazolium cation. The optimum hydrogen-ion concentration ranges from about 0.1 to 5M. The molar absorptivity at =352 nm is 1.81×10⁴ 1 · mole^–1 · cm^–1. The product is extracted as an ion-association complex with perchlorate into a mixture of hexanol and chlorobenzene. The kinetics of the reaction was investigated.