(224f) Density-Pressure-Temperature Measurements of Binary Mixtures of 1-Ethyl-3-Methylimidazolium Bis(trifluoromethylsulfonyl)Imide with Alcohols

Ionic liquids are chemical species basically constituted by cations and anions, which directly influence their physical-chemical properties, such as density, viscosity, and conductivity. The high thermal stability and low flammability contribute to the use of these substances as solvents, providing an attractive substitute for conventional organic solvents. When these ions are changed, their properties may be modified and controlled, making ILs very versatile in many industrial applications. Considered a class of green solvents, ionic liquids (ILs) present low vapor pressure, even at room temperature, allowing their use as solvents that can be recycled and reused in many applications. Thermophysical properties of pure ILs and their mixtures with other compounds are essential for equipment design, to understand possible physical, chemical and structural effects present in the mixtures, as well as testing and developing new theories of solutions. In this study, new experimental data for density-pressure-temperature measurements of binary mixtures of {1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][NTf₂]) + methanol, or + ethanol or + 1-propanol} have been measured using a vibrating tube densimeter at temperatures from T = (298.15 to 308.15) K and pressure range p= (0.1 – 40) MPa. From these experimental data, the excess molar volume has been calculated and correlated with the Redlich-Kister equation. Other volumetric properties such as partial molar volumes,V¯i"> apparent molar volumes, and infinite dilution volumes were determined. Density was measured using an Anton Paar DMA 4500 vibrating-tube densimeter combined with an external Anton Paar DMA HP high-pressure cell. The experimental density results have been correlated by the Tait-Tammann equation with the temperature and composition dependence parameters. The effects of the increase in the alkyl chains of the alcohols, temperature, and pressure on the density and volumetric properties have been analyzed. For all studied systems, the excess molar volume has a similar character. The excess molar volumes values decrease in absolute values in the following sequence: methanol > ethanol > 1-propanol. For all studied systems, the excess molar volumes values become less negative with increasing of temperature and pressure. The excess molar volumes values were very small (between -0.5 cm³·mol^-1 and 0.5 cm³·mol^-1) which is reasonable to believe that these mixtures could be considered ideal in terms of their volumetric properties in determined applications. The Extended Real Associated Solution Model (ERAS Model) has been used to correlate the experimental behavior of the excess molar volume of the studied systems. For all the systems, it is observed that the ERAS model was able to satisfactorily correlate the sigmoidal behavior of the experimental results of the excess molar volume although quantitative deviations are observed.