Liquid–Liquid Equilibrium for Ternary Systems of Water, Methacrylic Acid, and Alkyl Alcohols: Thermodynamic Analysis and Solvent Comparison

The development and research of biomass fuels have been paid more and more attention. The production of methacrylic acid is accompanied by a large amount of water and environmental pollution. Therefore, the separation of methacrylic acid from aqueous solution is of great significance for industrial production and environmental protection. The liquid–liquid equilibrium (LLE) for ternary systems of water + methacrylic acid + alcohol solvents at 303.2 K and 101.3 kPa was investigated. Thermodynamic models (NRTL and UNIQUAC) were used to correlate and regress the experimental data. The root-mean-square deviation (RMSD %) was used to evaluate the deviation between the experimental value and the calculated value, which were 1 and 1, respectively, indicating that the extractants selected in the experiment could well separate methacrylic acid from the aqueous solution, and 1-octanol exhibits better extraction performance. The correlation of LLE data is proven by MATLAB. In addition, the binary interactive parameters of the model regression are verified by MATLAB.