Influence of Alkyl Chain Length of Alcohols on the Extraction Efficiency of 3-Methoxybutyl Acetate in Aqueous Solution (C5–C8as Examples): Experimental Study, Thermodynamic Modeling, and Molecular Interaction Analysis

In order to recover 3-methoxybutyl acetate from an aqueous solution containing 3-methoxybutyl acetate, four n-alkanols (C5–C8) with different carbon chain lengths were selected as solvents for the liquid–liquid equilibrium (LLE) experiment of water + 3-methoxybutyl acetate + n-alkanols and the LLE data were measured at 303.2 K, 101.3 kPa. And by calculating the distribution coefficient (D) and separation factor (S), the separation effect of different extractants was compared and discussed. The obtained LLE data were correlated by NRTL and UNIQUAC models, and the binary interaction parameters of each system were determined. The model data for each system passed the hybrid surface analysis test of the Gibbs energy topology, indicating that the obtained model data are reliable. The root-mean-square deviation (RMSD) of the two models was less than 0.72 and 0.58%, respectively. The σ-profiles and interaction energy analysis were used to investigate the effect of alkyl chain length on separation efficiency. The analysis showed that the longer the alkyl chain length of n-alkanols, the higher the extraction efficiency of n-alkanols.