Liquid–Liquid Equilibria for the Ternary and Quaternary Systems of Water + Trimethylolpropane + (2-Ethylhexan-1-ol/Octan-1-ol) + Formaldehyde at 298.15 K

Ternary and quaternary liquid–liquid equilibria of three solutions (water + trimethylolpropane (TMP) + 2-ethylhexanol, water + TMP + octan-1-ol, and water + TMP + 2-ethylhexanol + formaldehyde) were studied at 298.15 K under atmospheric pressure. The consistency of the measured tie-line data was evaluated using the Othmer–Tobias, Bachman, and Hand equations. The properties of solvents, such as distribution constants, separation factors, and insolubilities, were examined in the ternary and quaternary liquid–liquid equilibrium systems. NRTL and UNIQUAC models were used to regress the ternary and quaternary systems and calculate binary interaction parameters. Finally, a comparison of experimental and calculated data, using the NRTL and UNIQUAC models, was performed.