Synthesis and Characterization of a New Ionic Liquid Soluble in Supercritical CO2

Supercritical fluids (SCF) are very interesting solvents with unique properties, such as high solute diffusivities, low viscosity and density values similar to liquids. All these features can be tuned with modifications in the pressure or temperature or the addition of modifiers [1]. Supercritical CO2 (sc-CO2) is one of the most promising alternative solvents because it is cheap, abundant, non-toxic, odorless, non-flammable, easily recycled, can be removed without difficulty from the product and has a low critical point (Pc=73,8 bar e Tc=31,1°C) [1]. However, its major limitation is the low dielectric constant and polarizability (in spite of the high quadrupolar moment), making only low molar mass and apolar molecules soluble in it. Polar or ionic compounds, common surfactants and polymers are usually not soluble in this supercritical fluid.