Quantitative analysis of the W-shaped excess heat capacities of binary liquid mixtures in the light of the local composition concept

• Published in: Fluid phase equilibria Vol. 235; no. 2; pp. 201 - 210
• Main Authors: Troncoso, Jacobo, Cerdeiriña, Claudio A., Carballo, Enrique, Romani, Luis
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 31-08-2005; Elsevier Science
• Subjects: Chemical thermodynamics; Chemistry; Critical phenomena; Crossover procedures; Exact sciences and technology; General and physical chemistry; Mixtures; Non-randomness; Thermodynamic properties; W-shaped excess heat capacities; W-shaped excess heat capacities; Critical phenomena; Non-randomness; Crossover procedures; Heat capacity; Excess parameter; Thermal properties; Binary mixture; Thermodynamic model; Critical phenomenon; Non random two liquid model; Liquid mixtures; Quantitative analysis
• ISSN: 0378-3812; 1879-0224
• DOI: 10.1016/j.fluid.2005.07.005

A detailed analysis on the capability of the NRTL model to describe W-shaped excess heat capacities
c
p
E
of binary mixtures is presented. Both the classical and crossover renormalized versions of the model are used to correlate experimental data for various polar
+
alkane systems. The results are analyzed and discussed after a careful description of the fitting strategies. The classical version allows a good thermodynamic description far away from the critical point to be obtained. It also provides a significant insight into the relation of
c
p
E
and the non-randomness of the molecular distribution in the mixture. On the other hand, the crossover-renormalized version qualitatively represents the behaviour of
c
p
E
both near the critical point and away from it; however, it exhibits some deficiencies from a quantitative point of view.