Propriedades termodinâmicas de misturas binárias: líquidos iônicos próticos e álcoois

Abstract

In this study, two protic ionic liquids (PILs) were produced, 2-hydroxyethylammonium acetate (2-HEAA) and 2-hydroxydiethylammonium acetate (2-HDEAA), with different cations. PILs were synthesized in laboratory by a neutralization reaction between organic acid and organic base. Then, they were dried by rotary evaporation under vacuum and the chemical structure was analyzed by H1 Nuclear Magnetic Resonance (H1NMR) tests. Binary mixtures (2-HEAA + 1-propanol, 2-HEAA + 2-propanol, 2-HDEAA + 1-propanol and 2-HDEAA + 2-propanol) were prepared in lidded test tubes and homogenized in vortex. A densimeter was used to measure density and speed of sound of the samples throughout the composition range, in the temperature range (293,15 - 323,15) K and at atmospheric pressure. The density and speed of sound presented decreasing values with increasing temperature and increasing values as the concentration of the ionic liquids increased. The excess molar volume was calculated using the experimental data of density and adjusted using the Redlich-Kister equation. The results obtained for this property were mostly negative, indicating the presence of attractive forces in the system and that takes to volume contraction. Isentropic compressibility was calculated using experimental data of density and speed of sound. For this property, the results grew with increasing temperature and decreased with increasing ionic liquid concentration in the mixture.