SAFT-VR modelling of the surface and bulk properties of imidazolium and pyridinium based ionic liquids with ten different anions

Abstract

Statistical associating fluid theory for potential of variable range has been used to provide an accurate thermophysical properties for 26 imidazolium and pyridinium-based families of ionic liquids (ILs) with different cationic structures combined with [PF6]−, [BF4]−, [NTf2]−, [Cl]−, [dca]−, [Triflate]−, [EtSO4]−, [lactate]−, [C(CN)3]− and [MeSO4]− anions. An appropriate set of molecular parameters were obtained by means of fitting the model predictions to experimental liquid densities over a wide temperature and pressure ranges. The overall absolute average relative deviation (AARD) between the calculated and experimental liquid densities is 0.12% over a wide range of temperature and pressure from 283 to 472K and 0.1–200MPa. The reliability and physical significance of the parameters were tested by calculation of thermodynamic derivative properties including isobaric thermal expansivity and isothermal compressibility of ILs. Moreover, the interfacial surface tension of ILs was calculated by density gradient theory (DGT) coupled with the SAFT-VR model. The results are in excellent agreement with the available experimental data.