High-Pressure and High-Temperature Density Data, Derivative Properties, and Group Contribution Models Applied for 1‑Methyl-3-octylimidazolium Trifluoromethanesulfonate, 1‑Butyl-1-methylpyrrolidinium Dicyanamide, and 1‑Ethyl-3-methylimidazolium Acetate Ionic Liquids

• Published in: Journal of chemical and engineering data Vol. 67; no. 5; pp. 1078 - 1088
• Main Authors: de Medeiros, Lucas H. G., Alves, Alanderson A. A., Feitosa, Filipe X., de Sant’Ana, Hosiberto B.
• Format: Journal Article
• Language: English
• Published: American Chemical Society 12-05-2022
• Subjects: Thermophysical and Thermochemical Properties
• ISSN: 0021-9568; 1520-5134
• DOI: 10.1021/acs.jced.2c00036

In this work, high-pressure and high-temperature density data for 1-methyl-3-octylimidazolium trifluoromethanesulfonate [C8C1Im]­[OTf], 1-butyl-1-methylpyrrolidinium dicyanamide [C4C1Pyr]­[DCA], and 1-ethyl-3-methylimidazolium acetate [C2C1Im]­[C1COO] ionic liquids (ILs) were determined at P = (0.2 to 100.0) MPa and T = (298.15 to 398.15) K with steps of 25 K, by using a tube vibration method. It was observed that density increases in the following sequence: [C4C1Pyr]­[DCA] < [C2C1Im]­[C1COO] < [C8C1Im]­[OTf], according to their intermolecular interactions. These experimental density data were correlated by using the Tammann–Tait equation, with the average absolute relative deviation less than 0.0090% for [C8C1Im]­[OTf] and [C2C1Im]­[C1COO] and less than 0.0220% for [C4C1Pyr]­[DCA]. From these data, the following derivative thermodynamic properties were calculated: isothermal compressibility (κT), isobaric expansivity (αp), thermal pressure coefficient (γv), and internal pressure (P i). Furthermore, the densities of the studied ILs were predicted using six different group contribution models. The best agreement between experimental and calculated data was obtained when the model proposed by Paduszynski and Domanska was applied.