Liquid-Liquid Equilibrium Study of 1-Dodecyl-3-Methyl-Imidazolium Dicyanamide + KH2PO4 + Water

The phase behavior of a new ternary aqueous two-phase system (ATPS) based on [1-Dodecyl-3-Methyl-Imidazolium][Dicyanamide] ionic liquid and an inorganic salt of KH2PO4 was investigated at two different salt concentrations and different temperatures of 288.15, 298.15, and 308.15 K, all under atmospheric pressure (0.1 MPa). This surface-active ionic liquid was chosen due to its similar properties to cationic surfactants and its widespread use in separation processes. The chemical structure of the synthesized ionic liquid was investigated using Fourier Transform InfraRed (FT-IR), Nuclear Magnetic Resonance (NMR), Diffuse Reflection Spectroscopy (DRS), residual chlorine test, and melting point test. The achieved experimental data correlated with the symmetrical local composition model of UNIQUAC-NRF with symmetric Pitzer−Debye−Hückel (PDH) theory. The results showed a minor influence of temperature on the separation process, and the salt ability in phase separation was increased at higher concentrations. A good agreement between correlated data and the experimental results was also found.