Estimation of the Density of Ionic Liquids over a Wide Temperature and Pressure Range: A Detailed Comparison between the Group Contribution Models Available in the Literature

Eight well-known group contribution
models capable of estimating
the density of ionic liquids have been examined to provide recommendations
for their application in process engineering. The models were carefully
evaluated using a methodology based on three main criteria: accuracy,
the flexibility of the functional groups, and their ability to describe
the great variety of cations and anions available in our data bank.
As a reference for all analyses, we took 17 663 experimental data
points of 201 different ionic liquids grouped into 9 cation families.
These data covered a wide range of temperatures (217.58–473.15
K) and pressures (0.0865–300.00 MPa), which allowed us to obtain
reliable conclusions regarding the performance of all models under
different operational conditions. The main outcome of this work is
a recommendation of the most feasible models for future use in practical
applications.