Azeotropic separation of isopropanol-water using natural hydrophobic deep eutectic solvents

Abstract

Inspired by the use of natural precursors for hydrophobic deep eutectic solvents (DESs) synthesis, in this work five different hydrophobic natural DESs have been prepared for azeotropic separation of IPA-water. The prepared natural hydrophobic DESs are also sustainable solvents having a low viscosity (≤50 mPa.s), high thermal degradation temperature (≥150 °C), and the density difference between water and the DESs are more than 50 kg m−3. The spectroscopy techniques such as H1NMR and FTIR were used to verify the formation of DESs. The pseudo-ternary liquid-liquid equilibrium phase diagram of isopropanol-water-DESs systems was then explored to study the extraction ability of synthesized DESs. The results show that all the DESs form type I ternary LLE diagram having broader immiscibility region with positive tie-line slopes and binodal curves depends upon the precursors used for the synthesis of hydrophobic DESs. In addition, the binary parameters for the extraction of IPA form water using natural hydrophobic were calculated using NRTL thermodynamic model.