Toward a novel approach for oxidative desulfurization (ODS) of diesel fuel: An efficient oxidation of thiophene derivatives with homogeneous and heterogeneous MTO/H2O2 systems

Organosulfur compounds in fuel oils are known to have a negative impact onto the environment because of SOx emissions from their combustion exhausts. As a consequence, removal of sulfur is becoming a worldwide challenge, also due to more and more stringent regulations. In this communication, our recent results obtained in the oxidation of benzothiophene (BTs) and dibenzothiophene (DBTs) derivatives contained in either a model fuel (MF) or an authentic diesel fuel (ADF), with homogeneous and heterogeneous rhenium catalysts and H2O2, will be showed. This catalytic method has been studied with the aim of designing an alternative environmentally benign oxidative desulfurization process (ODS), for oil industry. The quantitative conversion of both BTs and DBTs derivatives to the corresponding sulfones was obtained in several of the cases investigated. Excellent results in terms of both conversion of substrates and yields of sulfones were also obtained during oxidation of MF and ADF. Heterogeneous rhenium catalysts were stable systems to be used for several runs without any appreciable reduction of reactivity and selectivity.