Desulfurization of benzothiophene from model diesel fuel using experimental (dynamic electroreduction) and theoretical (DFT) approaches

In this paper, desulfurization of benzothiophene from model diesel fuel was investigated experimentally using dynamic electroreduction method. Also based on possible reaction pathway of benzothiophene electroreduction, the corresponding reduction potential was calculated by Gibbs free energy of relative reaction derived from DFT calculation and confirmed with experimental studies. This calculation revealed that the appropriate reduction potential for direct desulfurization of benzothiophene to Styrene is - 0.147 V. Finally, bulk desulfurization of emulsified model-diesel was done at best operational conditions (i.e., 0.3 V adsorption potential, -0.15 V reduction potential and frequency of 10 Hz). Initial and desulfurized fuels were analyzed with Fourier transform infrared spectroscopy, and GC-MS analysis showed the styrene and dihydrobenzothiophene were products of BT desulfurization. The total sulfur content was measured by the total elemental sulfur analyzer which revealed that 23.3%, 38.4% and 48.2% of sulfur content was converted to H2S after 4 h, 6 h, and 8 h respectively.