PREDICTION OF LIQUID DENSITY OF [C6MIM][NTF2] AND [C8MIM][NTF2] AT ATMOSPHERIC PRESSURE USING CPA EQUATION OF STATE

Abstract- The Cubic plus Association (CPA) equation of state (EoS) is a thermodynamic model that can calculate hydrogen bond forces between materials. The goal of developing the CPA was to present a model that is based on the Soave–Redlich–Kwong (SRK) EoS, which is widely used in the oil industry, complemented with an association term which is derived from Wertheim’s theory to describe the hydrogen bonds between materials (similar to the Statistical Associating Fluid Theory (SAFT)). In this study, 2B association scheme for ionic liquids, 1-hexyl-3 methylimidazolium bis (trifluoromethylsulfonyl) imide ([C6mim][NTf2]) and 1-octyl-3 methylimidazolium bis (trifluoromethylsulfonyl) imide ([C8mim][NTf2]) is used. The pure component parameters are obtained by fitting the predictions of the model to experimental vapor pressure and liquid density data. Two sets of parameters provide a good description of experimental liquid density.