Calculation of the T – X phase diagram of tetradecane + hexadecane and tetradecane + pentadecane under high pressure by the landau mean field theory

Pressure Effect on Thermodynamic Quantities for the Solid-Liquid Phase Transition in n-tridecane, n-hexadecane and n-octadecane

“…for the SLE of the mixtures (n-alkanes) [23,25,26]. Thermodynamic quantities can also be calculated as a function of pressure for the SLE of the n-alkanes.…”

“…In our previous studies [23,25,26] linear dependence of the coefficient 𝑎 2 on the temperature and concentration, and the quadratic dependence of 𝑎 4 on the concentration, have been assumed to describe the observed phase diagrams of tetradecane + hexadecane within the Landau phenomenological model. Recently, those dependences have also been assumed for the solidliquid equilibria in ntridecane [27].…”

“…Another approach by representing an excess Gibbs energy model [41], the effect of pressure on the liquidus curve in a (𝑇 − 𝑋) phase diagram has been studied for the binary mixtures (tetradecane + pentadecane and tetradecane + hexadecane) [21]. By means of the Landau phenomenological model which explains the observed behaviour of the 𝑇 − 𝑋 phase diagrams under pressure adequately, have been obtained for those binary mixtures in our recent study [25]. This also shows that the Landau mean field model is satisfactory to obtain the 𝑇 − 𝑋 phase diagram under high pressure, as we studied here for the binary mixtures of n-alkanes (1) + cyclohexane (2).…”

“…The temperaturedependent Raman spectra have been obtained for tetradecane, pentadecane and hexadecane [22]. 𝑇 − 𝑋 phase diagram and the thermodynamic quantities were also calculated for this binary mixture [23][24][25][26] and for the ntridecane [27] close to the liquid -solid phase transition using Landau phenomenological model in our recent studies.…”

“…Additionally, the thermodynamic quantities have been calculated as a function of temperature [23,26,27] using Landau phenomenological model. However, the effect of the pressure on the transition mechanism for the solidliquid equilibria, as studied for the phase diagrams of n-alkanes in our previous publications [25,27], should also be studied for the thermodynamic quantities in those binary mixtures. From this point of view, the present study differs from the already published works in the sense that it uses the Landau phenomenological model and also it differs from our previous works [23][24][25][26][27] since in this study, thermodynamic functions are calculated as a function of pressure for the binary mixtures studied.…”