Petroleum products (liqufied petroleum gas, motor gasolines, diesel fuels)) are in the first place used as the fuels for internal-combustion engines. Since the petroleum fuels have high sulfur content, where the sulfur during combustion is released into atmosphere in the form of oxide, just the elimination of this sulfur makes one of the aims of petroleum refinery processing in order to improve the ecological characteristics of fuels. By elimination of sulfur the characteristics of fuels are also improved. Various processes of desulfurization make the ways by which the above mentioned objectives are achieved. By hydrodesulfurization (HDS) sulfur is eliminated in in conditions of high pressure and temperature with great consumption of hydrogen. HDS is commercial process which shows certain limitations in achieving very low sulfur content, and for this reason various alternative processes of desulfurization such as extraction, adsorption and oxidative desulfurization are being nowadays developed. Mentioned processes are realized in milder reaction conditions, expensive hydrogen is not used, but the greater reactivity of aromatic sulfur compounds is achieved. In this work the effects of rate of stirring as well as the temperature of reaction on the conversion of dibenzothiophene (DBT) vere investigated. As the oxidant was used hydrogen peroxide, as the catalyst the tungstophoric acid and the tetraoctylammonium bromide as the surface active substance. After the oxidation the extraction of rafinant phase was carried out by dimetil formamide. The analysis of sulfur compounds was conducted by gas chromatograph (GC) method, 1HNMR spectroscopy and IR spectroscopy.