Liquid-Liquid Equilibrium Measurement and Modeling of Methyl 2-Hydroxyisobutyrate, Water, and Different Extractants at 303.2 K

To separate methyl 2-hydroxyisobutyrate from an aqueous solution, alkyl alcohols were selected as extractants. The liquid–liquid equilibrium data for the system {water + methyl 2-hydroxyisobutyrate + extractants (1-hexanol, 1-heptanol, 1-octanol, and 1-nonanol)} were determined at a temperature of 303.2 K. The partition coefficients and separation factors were calculated to assess the effectiveness of the extraction process. Additionally, the data were correlated using the NRTL and UNIQUAC models, with parameter regression conducted accordingly. The GMcal_TieLinesLL tool was utilized to evaluate the regression model parameters, and the results conformed to the Gibbs stability criterion. The present study further investigates the separation mechanism through analyses of σ-profile, deformation charge density, interaction energies, and Reduced Density Gradient (RDG) analysis. Ultimately, it was concluded that 1-nonanol exhibited the most effective extraction performance.