Abstract
Three protic ionic liquids with the ethylammonium cation, 2-hidroxy ethylammonium butanoate (2-HEAB), 2-hidroxy ethylammonium pentanoate (2-HEAP) and 2-hidroxy ethylammonium hexanoate (2-HEAH) were synthesized through acid- base neutralization reactions between ethanolamine and the corresponding organic acid. After purification, the salt formation was confirmed by FT-IR analysis. Thermophysical properties, such as density, refractive index, viscosity, heat capacity and degradation temperatures were experimentally determined. Melting points temperatures could not be determined within the temperature range studied. However, it was confirmed that these melting points are located below 323.15 K. Other thermodynamical properties, such as the thermal expansion coefficient, the molecular volume and the standard entropy were calculated from the experimental data through correlation equations. These results are in accordance with the consideration that the density is inversely proportional to the molecular volume and the density order is 2-HEAB > 2-HEAP > 2-HEAH.
