Abstract
The 12-tungstophosphoric acid (TPA)-catalyzed oxidative desulfurization of naphtha with H2O2 was investigated. All organosulfur compounds examined were efficiently oxidized with H2O2 and TPA catalyst in acetic acid (AcOH). The order of the oxidation reactivities was sulfides, disulfides > benzothiophenes > thiophenes. Methyl substituents on benzothiophenes and thiophenes increased the reactivity of the sulfur atom. The major oxidation products from the organosulfur compounds, except a few thiophenes, were the corresponding sulfones. The organosulfur compounds in octane were also oxidized with H2O2 and TPA catalyst in an octane/AcOH biphasic system. The oxidation proceeded in the AcOH phase and most oxidation products remained in this phase, resulting in the successive removal of the sulfur compounds from the octane phase. Using this oxidative treatment effectively reduced the sulfur content of naphtha, as the sulfur content was reduced to about 0.5 mass ppm after adsorption with silica gel. Hydrodesulfurization is an effective pretreatment for oxidative desulfurization of naphtha, by which the sulfur content can be reduced to below 0.1 mass ppm.
