Complex formation of vanadium with thioglycollic acid

Abstract

The complex formation between vanadium(IV) and thioglycollic acid has been studied by spectrophotometric, potentiometric and extraction methods. Thioglycollic acid is oxidized by air and the oxidation product, dithiodiglycollic acid, reacts with vanadium (IV) to form a blue coloured 1:1 complex. Provided that a large excess of reagent is present, the complex is stable in the whole pH range 4–9. In the presence of long-chain amines like Primene, the complex is easily extracted into a mixture of 50% n-octanol in benzene. The distribution coefficient is 18. The absorption curve in water as well as in the organic phase has a maximum at 630 nm, Beer's law is obeyed and the molar absorptivity in both solvents is 57.5.