Solvation Properties of Triethylammonium-Based Protic Ionic Liquids

Protic ionic liquids have numerous promising applications as solvents and are more straightforward and less expensive to synthesize than aprotic ionic liquids. This study expands the scarce knowledge on the solvation properties of protic ionic liquids by considering three triethylammonium salts: acetate, trifluoroacetate, and triflate. Additionally, they were characterized by means of TG/DSC analysis and low-temperature DSC in order to determine the liquid range temperature. The limiting activity coefficients of alkanes, alkenes, aromatic hydrocarbons, cycloalkanes, cyclohexene, and thiophene at 298.15 K were measured in these liquids. A higher solubility of hydrocarbons in triethylammonium salts than in many aprotic and several studied protic ionic liquids was observed. The selectivity of triethylammonium triflate for n-hexane/benzene separation is higher than that of sulfolane and N-methyl-2-pyrrolidinone used in industrial extraction processes.