Development of a New Group Contribution Method Based on GCVOL Model for the Estimation of Pure Ionic Liquid Density over a Wide Range of Temperature and Pressure

A new group contribution method based on GCVOL model developed by Elbro et al. in 1991 [Elbro, H. S.; Fredenslund, A.; Rasmussen, P. Ind. Chem. Eng. Res. 1991, 30, 2576–2582] is proposed for the estimation of ionic liquids density over a wide range of temperature and pressure. A total of 102 new groups for ionic liquids were introduced to the already 60 existing groups revised and proposed in 2003 by Ihmels and Gmehling [Ihmels, E. C.; Gmehling, J. Ind. Chem. Eng. Res. 2003, 42, 408–412]. These groups were proposed based on a collection of density data from literature. The databank contains data of 864 different ionic liquids, including dicationic and tricationic species, and a total of 21 845 data points, covering a temperature range of 251.62–473.15 K and a pressure range of 0.1–300.0 MPa. An average absolute relative deviation (%AARD) of 0.83% was obtained, indicating that our model is able to predict densities of a great variety of ionic liquids accurately.