Applying a QSPR correlation to the prediction of surface tensions of ionic liquids

Ionic liquids (ILs) have attracted large amount of interest due to their unique properties. Although large effort has been focused on the investigation f their potential application, characterization of ILs properties and structure–property relationships of ILs are poorly understood. Computer aided olecular design (CAMD) of ionic liquids (ILs) can only be carried if predictive computational methods for the ILs properties are available. The imited availability of experimental data and their quality have been preventing the development of such tools. Based on experimental surface ension data collected from the literature and measured at our laboratory, it is here shown how a quantitative structure–property relationship (QSPR) orrelation for parachors can be used along with an estimation method for the densities to predict the surface tensions of ILs. It is shown that a good greement with literature data is obtained. For circa 40 ionic liquids studied a mean percent deviation (MPD) of 5.75% with a maximum deviation nferior to 16% was observed. A correlation of the surface tensions with the molecular volumes of the ILs was developed for estimation of the urface tensions at room temperature. It is shown that it can describe the experimental data available within a 4.5% deviation. The correlations here eveloped can thus be used to evaluate the surface tension of ILs for use in process design or in the CAMD of new ionic liquids. 2008 Elsevier B.V. All rights reserved.