Measurements and Correlation of High-Pressure Densities of Imidazolium-Based Ionic Liquids

In the present work, experimental density measurements are reported along with the derived thermodynamic properties, such as the isothermal compressibility (κ<sub><i>T</i></sub>), the isobaric expansivity (α<sub><i>p</i></sub>), and the thermal pressure coefficient (γ<sub><i>v</i></sub>) for imidazolium-based ionic liquids (ILs), namely, 1-ethyl-3-methylimidazolium methylsulfate [C<sub>2</sub>mim][MeSO<sub>4</sub>], 1-ethyl-3-methylimidazolium ethylsulfate [C<sub>2</sub>mim][EtSO<sub>4</sub>], 1,3-diethylimidazolium bis(trifluoromethylsulfonyl)imide [C<sub>2</sub>eim][Tf<sub>2</sub>N], and 1-decyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [C<sub>10</sub>mim][Tf<sub>2</sub>N] in the pressure (0.10 < <i>P</i>/MPa < 35.00) and temperature (293.15 < <i>T</i>/K < 393.15) domains. It is shown that experimental densities are in good agreement with the predicted densities obtained by the Gardas and Coutinho method and the correlation using the Tait equation and Sanchez−Lacombe equation of state.