2-aminobenzenethiol and its disulphide as complexing agents for metal ions. I. Protonation equilibria in water-ethanol solution (I + I, v/v), redox properties

Some properties of 2-aminobenzenethiol (2-abt) solutions, in ethanol and in water-ethanol mixtures (stability against auto-oxidation, UV and IR spectral features and effect of oxidation on these features) are studied, and the protonation constants of 2-abt and its oxidation product, the disulphide 2.2'-dithiobis(benzeneamine) (dtba) in water-ethanol (I + I, v/v), in 1.0 mol l–1 sodium perchlorate, at 25°C, are determined. The results are, for 2-abt : log β1 = 7.104 ± 0.01, log β2 = 9.732 ± 0.04 ; for dtba, log β1 = 2.309 ± 0.02 log β2 = 3.673 ± 0.05. Qualitative tests for some metal ions using dtba as a reagent are described