Vanadium(V) as an oxidant for thiol compounds

Vanadium(V) is shown to oxidize a number of thiol compounds to the corresponding disulphides. A photometric procedure for the estimation of vanadium(V) in the presence of vanadium (IV) and diverse ions is described. A reinvestigation of the reaction of se(IV) in 4-8M hydrochloric acid with thiosalicylic acid confirms that the Se(IV) acts purely as an oxidant to yield only the corresponding disulphide (RSSR) and not an equimolar mixture of RSSeSR and RSSR.