Extractive and oxidative desulfurization of model oil in polyethylene glycol

Abstract

The polyethylene glycol 200 (PEG-200) was explored as a green solvent for extractive and catalytic oxidative desulfurization (ODS) process. ODS experiments were conducted using model oil with SeO₂ as catalyst and H₂O₂ as an oxidant. The desulfurization system was very efficient for the removal of DBTs under mild conditions. The reaction conditions such as the amount of PEG-200, temperature, mole ratio of H₂O₂ and sulfur compound were investigated. The different sulfur substrates removed by this desulfurization system were also investigated and the following order was found: dibenzothiophene (DBT) > 4,6-dimethyl dibenzothiophene (4,6-DMBT) > benzothiophene (BT). The desulfurization system could be used 7 times without significant decrease in activity. The possible catalytic mechanism seems that peroxyseleninic acid may be considered as the true oxidative agent formed from hydrogen peroxide and selenium dioxide, which translated the DBT to the corresponding sulfone.