Comparison of Two Types of Crossover Soave-Redlich-Kwong Equations of State for Derivative Properties of n-Alkanes

In this work, two different Crossover Soave-Redlich-Kwong (SRK) Equations of State (EoS) were applied to incorporate the density fluctuations into the classical model for the representation of derivative properties of selected n-alkanes. Both methods, the first based on the renormalization of the Landau-Ginzburg expansion and the second based on the phase-space cell approximation, are capable of describing the non-classical behavior of the molar heat capacities and speed of sound close to the critical point. Nevertheless, the overall performance of the crossover equation is similar to the cubic model, since the non-mean-field EoS reduce to the classical model far from the critical region. Additionally, the comparison of the crossover equations indicates that the Kernel term is useful for the correct representation of the heat capacity at constant volume, as well as other properties related to the weak divergence at the critical point, over a wider range of conditions.