Oxidative Desulfurization of Thiophenic Components by Dawson Polyoxometalate Supported Catalyst

In this work, a new catalyst based on Dawson salt, H9P2W15V3O62, is presented for oxidation of high stable sulfur compounds. The new catalyst, H9P2W15V3O62/TiO2, is synthesized by sol-gel method. The structure of catalyst and salt has been characterized by FT-IR, XRD and UV spectrophotometry. The performance of catalyst has been studied in the oxidative desulfurization of aromatic components, benzothiophene and dibenzothiophene (ones of the most resistant sulfuric components to oxidation), mixed with n-octane under mild operation conditions (temperature less than 70 oC and atmospheric pressure). The reactor tests’ results illustrated that the synthesized catalyst has a suitable performance (achieved 100% conversion of debenzothiophene and 78% conversion of benzothiophene in less than 20 minutes) in oxidative desulfurization. The process conditions (temperature, catalyst loading and a mole ratio of oxygen to sulfur) have been optimized by Taguchi Experimental Design method. Our results show that at 50 oC, the mole ratio of 6 for oxygen/sulfur and catalyst loading 7.5 g/L are optimum conditions.