Study on the Separating of Cyclohexane + 1-Propanol Azeotrope System by Using Ionic Liquid Extractants

As crucial additives and solvents in organic synthesis, the efficient separation of the cyclohexane + 1-propanol azeotropic system holds significant industrial importance. This study systematically evaluates the separation efficiency of ionic liquids for this azeotropic system using the COSMO-RS model. First, a database containing 364 ionic liquids was constructed by combining 26 anions with 14 cations, from which the high-performance extractant C5A20 was selected. Subsequently, vapor-liquid phase equilibrium experiments verified the reliability of the model predictions, demonstrating that the azeotropic point completely disappears when the mole fraction of C5A20 reaches 0.02. Further analysis through σ-profiles and hydrogen bonding interactions revealed the selective separation mechanism of C5A20 towards 1-propanol, providing molecular-level theoretical insights for the rational design of efficient ionic liquid extractants.