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_T), the isobaric expansivity (α_p), and the thermal pressure coefficient (γ_v) for imidazolium-based ionic liquids (ILs), namely, 1-ethyl-3-methylimidazolium methylsulfate [C₂mim][MeSO₄], 1-ethyl-3-methylimidazolium ethylsulfate [C₂mim][EtSO₄], 1,3-diethylimidazolium bis(trifluoromethylsulfonyl)imide [C₂eim][Tf₂N], and 1-decyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [C₁₀mim][Tf₂N] in the pressure (0.10 < P/MPa < 35.00) and temperature (293.15 < T/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.