Electrochemical study of fast blue BB. A green strategy for sulfination of fast blue BB

For the first time the electrochemical behavior of fast blue BB (FBBB) has been studied by cyclic voltammetry, chronoamperometry and controlled potential coulometry. We found that at all studied pH values, the cyclic voltammograms show one anodic peak and the corresponding cathodic peak. The Pourbaix diagram of FBBB, the pKa values of all species in the Pourbaix diagram and the diffusion coefficient of FBBB have also been calculated. In addition, the electrochemical synthesis of arylsulfonyl-fast blue BB derivatives was carried out via the controlled-potential oxidation of FBBB in the presence of arylsulfinic acids, in an undivided cell in a water/ethanol mixture using a carbon anode. Our data demonstrate that the reaction of electrogenerated FBBBox with arylsulfinic acids can lead to arylsulfonyl-FBBB. This research has led to the development of an environmentally friendly method for the synthesis of some new sulfone derivatives of FBBB with high yields and without using any toxic reagents and solvents.