Density for M−2−HEAA + 2-HEAA and HEAPe + 2-HEAA binary mixtures and pure compounds at high pressure

In this work, the effects of cations and anions on the density of pure compounds N-methyl-2-hydroxyethylammonium acetate [m-2-HEAA], 2-hydroxyethylammonium acetate [2-HEAA], and 2-hydroxyethylammonium pentanoate [HEAPe], as well as their mixtures following mixtures [m-2-HEAA] + [2-HEAA] and [HEAPe] + [2-HEAA], were determined. These measurements were conducted at pressures up to 100.0 MPa and within a temperature range of T = (298.15 to 373.15) K using the vibrating tube method. A Tammann-Tait equation correlated the experimental density data with an average absolute relative deviation ($\%AARD$) less than 0.065 %. From this Tammann-Tait equation, the following derivative properties were determined for pure compounds: isothermal compressibility (${\kappa }_T$), isobaric expansivity (${\alpha }_p$), thermal pressure coefficient (${\gamma }_V$)_, and internal pressure ($P_i$). For the binary mixtures, excess molar volume (V^E) was determined. These data showed that N-methyl-2-hydroxyethylammonium anion impacts more than pentanoate cation when compared to their effect on the ILs packing efficiency. Furthermore, density data was estimated using Paduszynski and Domanska, Lazzus, and Evangelista et al. group contributing methods.