Oxidation mechanism of dibenzothiophene compounds: A computational study

The potential energy surfaces of the oxidation of three model heterocyclic organic sulfides dibenzothiophene (DBT), 4-methylbenzothiophene (MDBT) and 4,6-dimethyldibenzothiophene (2MDBT) were examined using HCO3H as oxidants adopting MP2, ωB97X-D, M06-2X and B3LYP methods at 6-311+G (d,p) level. The stationary points on the potential energy surfaces for the first and second oxidation reaction were fully optimized and characterized. The natural orbital population analysis (NPA) was also performed to understand the charge distribution. The calculated results may contribute to understanding the reaction mechanism of the ODS of refractory DBT sulfides.