Thermophysical Properties of Mixtures Containing Cholinium l-Alaninate and Water, Ethanol, or Propan-1-ol

Abstract

Choline amino acid ionic liquids (CAAILs) provide a greeneralternativeto classical ionic liquids, such as the ones based on imidazoliumcations, since they can be obtained from natural sources with largerbiodegradability. Given that most industrial extractions are performedin either aqueous or alcoholic media, the thermophysical characterizationof binary mixtures containing these solvents is very important forprocess design. In this work, the influences of the mole fractionof ionic liquid and of temperature on the thermophysical propertiesof binary mixtures containing water, ethanol, or propan-1-ol and cholinium l-alaninate ([Ch][Ala]), a well-known CAAIL, were studied. Dynamicviscosity, shear stress, torque (T = 288.15 -308.15 K), electrical conductivity (T = 298.15 K),and density (T = 293.15, 298.15, 303.15 K) were measuredat 0.1 MPa, and the corresponding excess volumes were calculated andfitted to a Redlich-Kister (RK) equation. Moreover, the effectof temperature on density (T = 288.15 - 323.15K), dynamic viscosity (T = 288.15 - 323.15K), and refractive index (T = 288.15 - 343.15K) of the synthesized [Ch][Ala] was also evaluated and compared withliterature. Dynamic viscosities of the pure components were determinedand fitted using the Vogel-Fulcher-Tammann-Hesse(VFTH) equation.