Experimental measurement and prediction of (liquid + liquid + liquid) equilibrium for the system (n-hexadecane + water + triacetin)

• Phase diagram for the system n-hexadecane + water + triacetin was established at T = 296.15 K and atmospheric pressure (0.1 MPa).
• Both NRTL and UNIQUAC activity coefficient model adequately predicts the LLLE of the ternary system.
• The phase equilibrium of the system is predominantly dictated by enthalpic contributions to the activity coefficient.

The phase diagram for the ternary system containing (n-hexadecane + water + triacetin) was obtained experimentally at T = 296.15 K and ambient pressure. Results show that this system is of Type 3 according to the Treybal classification of ternary system. NRTL and UNIQUAC interaction parameters were calculated from binary phase equilibrium values and were used to predict the (liquid + liquid + liquid) equilibrium (LLLE) region. Results indicated that both NRTL and UNIQUAC could predict the LLLE region of the system with similar precision as indicated by the comparable standard deviations. This indicates that the enthalpic contribution to the activity coefficient is predominant and entropic contributions can be neglected.