LLE Data of (Water + 2-Methoxy-phenol + C₉–C₁₁ Alcohols) Ternary Systems at 303.2 K: Experimental Investigation and Modeling via Thermodynamic and Linear Solvation Energy Relationship Approaches

This study investigated the liquid–liquid equilibrium (LLE) behavior of three ternary systems containing water, 2-methoxy-phenol, and either 1-nonanol, 1-decanol, or 1-undecanol at 303.2 K and 101.3 kPa. Tie-line data were obtained through Karl Fischer titration and HPLC analysis. The experimental LLE data were successfully correlated using both NRTL and UNIQUAC thermodynamic models, achieving excellent agreement with root-mean-square deviation values below 0.3%. Activity coefficient analysis using optimized NRTL binary parameters revealed distinct behavioral patterns: 2-methoxy-phenol exhibited negative deviations from ideality in the organic phase, while all other components showed positive deviations. Water activity coefficients in the aqueous phase remained near unity with minimal deviation from ideal behavior. Extraction performance evaluation through distribution coefficients and selectivities demonstrated that all three alcohols provided comparable selectivity values ranging from 491 to 651. However, distribution coefficients showed a clear inverse relationship with alcohol chain length, decreasing in the order 1-nonanol > 1-decanol > 1-undecanol. Catalán linear solvation energy relationship analysis identified dipolarity and basicity as factors that enhance distribution coefficients, while acidity and polarizability negatively influence extraction efficiency.