Aryldiazosulfonates and aryldiazosulfonic acids. IV. Scission of aryldiazosulfonic acids by action of strong acids

In the absence of light, and in dilute solutions in which it is completely dissociated, benzenediazosulfonic acid is stable for an unlimited period of time and its UV-VIS spectrum is identical with that of benzenediazosulfona te. As dissociation regresses by increasing of the concentration over 10%, or under the action of a strong, concentrated acid such as sulfuric acid, b enzenediazosulfonic acid is converted in two steps into the Benzenediazoniu m salt. In this process the intermediates are benzenediazohydroxide and its protonated products. The whole process may be spectrophotometrically inves tigated in UV, the visible absorption being lost in the first, very fast st ep of the transformation.