(382ad) High-Pressure Densities and Derived Properties for Binary Mixtures Containing 1-Ethyl-3-Methylimidazolium-Thiocyanate + Alcohols

Authors: 
D'Angelo, J. V. H., Universidade Estadual de Campinas
Hauk, D. B., Universidade Estadual de Campinas
Ionic liquids (ILs) containing Imidazolium cations represent an important subclass of these compounds and many of them are commercially available. The possibility of varying the substituents in the nitrogen atom makes it possible to modify their physicochemical properties. This opens the way for the development of real designer solvents with applications in various areas of science and industry. They have been used, for example, in catalysis, extraction processes, electrochemistry and batteries, hydrolysis of biomass, lubricants and many other applications. In the present study, density for binary liquid mixtures of {1-Ethyl-3-methylimidazolium-thiocyanate (EMIM SCN) + ethanol, or + 1-propanol, or + 1-butanol} have been determined as a function of composition at temperatures (298,15, 303,15 and 308,15) K and pressure up to 40 MPa. Densities data were measured using an Anton Paar DMA 4500 vibrating-tube densimeter coupled to an external Anton Paar DMA HP high-pressure cell. These results have been used to calculate derived volumetric properties such as excess molar volumes (VE), apparent molar volumes (VΦi) and partial molar volumes (Vi). The experimental results of density have been fit to the Tait-Tammann equation and used to calculate the isothermal compressibility (κT) and the thermal expansion coefficient (αp). For all systems studied, the values of were negative and increased with the increasing temperature and decreased with the increasing pressure. Furthermore, spectroscopic properties (FT-IR, 1H-NMR and 13C-NMR) have been investigated to elucidate the main structural and interactional phenomena present in the systems studied. The results suggest that the structural effects and intermolecular interactions must outweigh other possible effects present in the mixtures studied.