Kinetics of Electrooxidation of Dimethyl Sulfoxide on a Platinum Electrode with Sulphuric Acid and Alkaline Solutions

In this work, an electrochemical study of the mechanism of electrooxidation of dimethyl sulfoxide (DMSO) on a platinum electrode in acidic and alkaline solutions was carried out. On stationary polarization anodic curves taken within DMSO in an acidic and alkaline environment, the processing currents are processed manually than in dissolved light. When analyzing linear sections of anodic voltammograms, the values of the coefficients of the Tafel equation were achieved. This definition defines the current density measurement range and conditions for the electrooxidation of DMSO on a platinum (Pt) electrode. Electrolysis was carried out at controlled current densities in an electrolyzer without separation and with separation of the anode and cathode compartments using MK-40, MA-40 membranes and a fluoropolymer sulfcationite membrane MF-4SK. The high electrical conductivity and selectivity of the membranes ensures good performance of the electrolysis process and obtains a high-purity final product. Raman spectroscopy and gas chromatography-mass spectrometry have confirmed that the products of DMSO electrooxidation in an acidic environment are dimethyl sulfone (DMSO2) and methanesulfonic acid (MSA), and in an alkaline environment DMSO2 and sodium methanesulfonate. The method of quantum chemical calculations showed good adsorption of DMSO molecules on platinum within the framework of the cluster model. It has been established that the formation of MSA on the surface of a platinum electrode at high current densities occurs via the radical ion mechanism, by breaking the C–S bond. Based on the experimental results obtained, a scheme for the electrochemical oxidation of dimethyl sulfoxide on platinum is proposed.