Ensieh Ghasemian - Faculty of Science, Ilam University, P.O. Box 69315516, Ilam, Iran
Hadis Parhiz - Faculty of Science, Ilam University, P.O. Box 69315516, Ilam, Iran

Ionic liquids (ILs) have attracted a large amount of interest due to their unique properties. Alarge effort has been focused on the investigation of their potential application,characterization of ILs properties and structure–property relationships. In this paper a simpleequation has been used to predicting the surface tensions of pure Ionic liquids based onenthalpy of vaporization. Acentric factor, critical temperature, and critical pressure of ionicliquids are necessary inputs for this prediction. The average relative error obtained from thecomparison of experimental and calculated surface tension values for studied ionic liquids areless than 2%. Therefore, the model has good accuracy in comparison with other predictiveequations.