ACYCLIC AND CYCLIC POLYTHIAMONOAZA-ALKANE AND POLYTHIADIAZA-ALKANE HYDRAZONE DERIVATIVES AS CHROMOGENIC EXTRACTANTS FOR SILVER ION

Acyclic and cyclic dithiaza-, tetrathiaza- and tetrathiadiazaalkane de rivatives bearing 6-trifluoromethyl-2,4-dinitrophenylhydrazono moietie s as chromogenic groups on the nitrogen atoms of the alkanes were synt hesized and used as extractants for some class ab and b metal ions in liquid-liquid extraction, The extraction behavior was estimated by usi ng the spectral change in the organic phase containing the chromoionop hore, All of these compounds exhibited high Ag+ selectivity relative t o other class ab and b metal ions, which are soft Lewis acids, even ag ainst Hg2+. In the extraction of silver nitrate from aqueous acidic an d basic phases, interestingly, the absorption maxima of the organic ph ases containing the chromoionophores in the visible absorption region shifted to shorter and longer wavelengths, respectively, Among the chr omoionophores used here, the acyclic tetrathiazaalkane hydrazone 4b ex tracted Ag+ most effectively from an aqueous phase into a 1,2-dichloro ethane phase under all the extraction conditions studied, A linear cal ibration graph up to 5.5 x 10(-5) mol dm(-3) Ag+ in the aqueous neutra l phase was obtained spectrophotometrically by using the acyclic tetra thiazaalkane hydrazone 4b and the determination of Ag+ in a silver sol der sample was achieved from the calibration graph.