The liquid-liquid equilibrium (LLE) data of ternary systems water + diethoxymethane (DEM) + Methyl tert-butyl ether (MTBE) and water + DEM + Methyl isobutyl ketone (MIBK) were determined experimentally at 298.15, 308.15, and 318.15 K under the atmospheric pressure condition. The solvents' extraction capacity was assessed by the solute distribution coefficient and selectivity. Othmer-Tobias and Hand equations were utilized to validate the accuracy and reliability of the measured data, which the linear correlation (R2) ≥ 0.99. Experimental LLE data was correlated utilizing the NRTL and UNIQUAC thermodynamic models with all of the RMSD values below 0.002 meaning that each ternary system satisfactory agreement at temperatures studied. Also, the reliability of binary interaction parameters was validated by the topological analysis based on the Gibbs tangent plane test using a graphical user interface.