A GROUP CONTRIBUTION METHOD TO PREDICT ρ-T-POF IONIC LIQUIDS

A simple and accurate group contribution method to predict the density of ionic liquids is presented. The proposed method follows the classical architecture of the group contribution concept to evaluate the molar volume at 298.15 K and 0.101 MPa. A set of 210 ionic liquids has been used to obtain the contributions for anion and cation groups. Once the molar volume is evaluated and expressed as density, values at several temperatures and pressures are calculated using a linear model that only uses the reference density value. Density data of 76 ionic liquids (3530 data points) were used to obtain the linear model for wide ranges of temperatures and pressures: 258 to 393 K and 0.09 to 207 MPa. Results show that the new group contribution method (R2 = 0.9687; AARD = 1.93%) and the linear model (R2 = 0.9989; AARD = 0.73%) are accurate enough and give lower deviations than other models available in the literature.