Kinetics and Mechanism of 2,2′-bipyridine Catalysed Chromium(VI) Oxidation of Dimethyl Sulfoxide in the Presence and Absence of Surfactants †

In the 2,2′-bipyridine (bipy) catalysed Cr^VI oxidation of dimethyl sulfoxide (DMSO) to dimethyl sulfone, the Cr^VI–bipy complex formed at the pre - equilibrium step undergoes a nucleophilic attack by the S or O of DMSO to form a positively charged reactive intermediate. This intermediate experiences an oxygen transfer or a ligand coupling to give the products. The anionic surfactant (SDS) accelerates the process while the cationic surfactant (CPC) retards the reaction.