Oxidative desulfurization of light gas oil and vacuum gas oil by oxidationand solvent extraction

The oxidation of model sulfur compounds (thiophene derivatives, benzothioph ene derivatives, and dibenzothiophene derivatives), straight run-light gas oil (SR-LGO, S: 1.35 wt %), and vacuum gas oil (VGO, S: 2.17 wt %) were con ducted with a mixture of hydrogen peroxide and formic acid. The thiophene d erivatives with 5.696 to 5.716 electron densities on the sulfur atoms could not be oxidized at 50 degreesC. Benzo[b]thiophene with 5.739 electron dens ity and other benzothiophene and dibenzothiophenes with higher electron den sities could be oxidized. The sulfur compounds in SR-LGO and VGO appeared t o be oxidized to a detectable levels (c.a., 0.01 wt % S) by GC-FPD analysis . The IR spectra of oxidized SR-LGO and VGO showed that sulfones were forme d by oxidation. The removal of sulfur compounds by extraction became more e ffective for the oxidized samples than for the original samples. Lighter su lfur compounds were preferentially extracted. The extraction efficiencies o f solvents, i.e., N,N'-dimethylformamide (DMF), acetonitrile (ACN), methano l, varied greatly. The most effective solvent for the removal of sulfur com pounds was DMF. The recovery of oil was, however, lowest with DMF.