Density and isothermal compressibility for two trialkylimidazolium-based ionic liquids at temperatures from (278 to 398) K and up to 120 MPa. (February 2015)

• Record Type: Journal Article
• Authors: Gaciño, Félix M.; Regueira, Teresa; Comuñas, María J.P.; Lugo, Luis; Fernández, Josefa
• Is Part Of: Journal of chemical thermodynamics. Volume 81(2015:Feb.)
• Page Start: 124
• Page End: 130
• Publication Date: 2015-02
• Subjects: Density -- Pressure -- Ionic liquid -- Isothermal compressibility -- Thermal expansivity; Thermodynamics -- Periodicals; Thermochemistry -- Periodicals; Thermodynamique -- Périodiques; Thermochimie -- Périodiques; Thermochemistry; Thermodynamics; Periodicals; 541.369
• DOI: 10.1016/j.jct.2014.09.014
• Languages: English
• ISSNs: 0021-9614

Abstract

Graphical abstract: Highlights: Densities of two ILs were measured from T = (278.15 to 398.15) K and up to 120 MPa. Experimental densities were correlated to a Tammann Tait equation with a standard deviation lower than 2.8 · 10 −4 g · cm −3 . Gardas–Coutinho method predicts ρ with an AAD of 0.5% and 1% for [C4 C1 C1 Im][(C2 F5 )3 PF3 ] and [C4 C1 C1 Im][NTf2 ], respectively. αp isotherms present an intersection point at moderate pressures for both ILs. The addition of a methylene group in the cation decreases the density. Abstract: In this paper, a densimeter based on vibrating tube principle is used to determine experimentally the density of 1-butyl-2, 3-dimethylimidazolium tris(pentafluoroethyl)trifluorophosphate and 1-butyl-2, 3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide at temperatures between (278.15 and 398.15) K and at pressures up to 120 MPa. The apparatus was calibrated by using water, vacuum and bromobenzene. The Tammann–Tait equation of state was used to correlate ( p, T, ρ ) results with standard deviations around 2 · 10 −4 g · cm −3 . Other volumetric properties, such as isothermal compressibility and isobaric thermal expansivity, were obtained from this equation. For each ionic liquid, the αp isotherms present a crossing point within the experimental pressure range. Besides, the effect that the C2-methylation in the imidazolium cation provokes on density values is analyzed. The prediction ability of the group contribution methods of Gardas and Coutinho and Jacquemin et al. were tested with the experimental densities.