The reductions of sulfur content in gasoline and diesel fuel are great environmental concern to reduce the motor vehicle emissions. A hydrodesulfurization process has been used in many refineries, however, the new effective desulfurization processes are needed to meet the lower sulfur level regulations. Oxidative desulfurization in acetonitrile biphasic system, has been proposed in recent years, can be oxidize the unreactive sulfur compounds in the hydrodesulfurization. The polar benzothiophenes and dibenzothiophenes, they are major sulfur-containing compounds in fossil fuels, are extracted into the polar acetonitrile phase and oxidized. Oxidative desulfurization can also be oxidize 4,6-dimethyldibenzothiophene effectively, one of the most unreactive sulfur compounds during hydrodesulfurization. For the oxidative desulfurization process design and development, liquid-liquid equilibria (LLE) for acetonitrile biphasic systems and the partition coefficients of sulfur compounds are needed as a fundamental information. In this work, therefore, the partition coefficients of sulfur compounds, benzothyophene, dibenzothiophene and 4,6-dimethyldibenzothiophene, and benzothyophene 1,1-dioxide and dibenzothiophene 5,5-dioxide, major products of oxidative desulfurization reaction, for acetonitrile + n-alkane systems were measured. Furthermore, the partition coefficients were also correlated with NRTL activity coefficient model to simulate the partition conditions of sulfur compounds in acetonitrile + n-alkane systems.