Study of the electrochemical oxidation of 4,6-dimethyldibenzothiophene on a BDD electrode employing different techniques
| Autor: | A.F. Roig Navarro, M.M. Dávila Jiménez, J.V. Sancho Llopis, O. Ornelas Dávila, Ignasi Sirés, J. Beltrán Arandes, L. Lacalle Bergeron, Enric Brillas |
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| Rok vydání: | 2021 |
| Předmět: |
General Chemical Engineering
Analytical chemistry 02 engineering and technology 010402 general chemistry Electrochemistry Mass spectrometry 01 natural sciences Analytical Chemistry law.invention chemistry.chemical_compound Reaction rate constant law Bulk electrolysis Desulfurization Electrolysis Sulfoxide Oxidació electroquímica 021001 nanoscience & nanotechnology 0104 chemical sciences Electrolytic oxidation chemistry Dessulfuració Differential pulse voltammetry Cyclic voltammetry 0210 nano-technology |
| Zdroj: | Dipòsit Digital de la UB Universidad de Barcelona |
| Popis: | The electrochemical oxidation of 4,6-dimethyldibenzothiophene (4,6-DMDBT) at low concentrations on a BDD anode was investigated in a monophasic acetonitrile (93.5% v/v)–water (6.5% v/v, 0.01 M LiClO4) solution. Two oxidation steps related to the sequential formation of sulfoxide and sulfone derivatives were identified. Kinetic parameters such as the electron transfer coefficient α, the number of electrons nα involved in the rate-determining step, the total number of electrons n, the reaction rate constant k0 and the diffusion coefficient D of 4,6-DMDBT for the first transformation were determined by cyclic voltammetry, differential pulse voltammetry (DPV), square wave voltammetry and bulk electrolysis under potentiostatic conditions. The process was bielectronic with α = 0.57, nα = 1, k0 = 7.46 × 10−6 cm s−1 and D = 2.30 × 10−6 cm2 s−1. DPV was the most sensitive electroanalytical technique. Using 27 mg L−1 of 4,6-DMTDB, DPV allowed determining a conversion of 91% to sulfoxide after 60 min of electrolysis in a BDD/BDD cell at an anodic potential of 1.50 V, with an apparent rate constant of 0.034 min−1. The electrochemical characterization was corroborated via gas chromatography–mass spectrometry and ultra-high performance liquid chromatography coupled to electrospray ionization and quadrupole time-of-flight mass spectrometry, confirming the formation of the sulfoxide in the first step and the sulfone in the second one as main products, alongside a minor proportion of dimers. |
| Databáze: | OpenAIRE |
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