Calculation of the Phase Diagrams (T – X and T – P) and the Thermodynamic Quantities for the Solid – Liquid Equilibria in n-tridecane

Authors : Özlem TARI İLGİN, Hamit YURTSEVEN

Pages : 37-45

Doi:10.5541/ijot.1267822

View : 43 | Download : 57

Publication Date : 2023-09-01

Article Type : Research Paper

Abstract :The solid – liquid equilibria in n-tridecane is investigated by calculating phase diagrams and the thermodynamic quantities using the Landau phenomenological model. By expanding the free energy in terms of the order parameter of the solid phase, the phase line equations are fitted to the experimental data for the T – X and T – P phase diagrams from the literature. The temperature dependences of the thermodynamic quantities insert ignore into journalissuearticles values(order parameter ψ, susceptibility χ_ψ, free energy F, the heat capacity C, entropy S and the enthalpy H); are predicted for the n-tridecane from this model. Our results give that the slope dT⁄dP≅2 \`K/MPa\` for n-C13 to n-C17. ψ varies with T as ψ~insert ignore into journalissuearticles values(T-T_m );^insert ignore into journalissuearticles values(1⁄2); above T_m. It is linear for the 〖χ_ψ〗^insert ignore into journalissuearticles values(-1);, Sinsert ignore into journalissuearticles values(T); and Cinsert ignore into journalissuearticles values(T);, and quadratic for the Finsert ignore into journalissuearticles values(T); and Hinsert ignore into journalissuearticles values(T); in n-tridecane. This indicates that the Landau model, describes the observed behaviour of the phase diagrams satisfactorily for the solid – liquid equilibria in n-tridecane. Predictions of the thermodynamic quantities can also be compared with the measurements and predictions of some other theoretical models. The pressure effect, in particular, on the solid – liquid equilibria in n-tridecane can also be investigated under the model studied here.
Keywords : Solid liquid equilibria, T X and T P phase diagrams, Thermodynamic quantities, n tridecane