Dr. José Matías Garrido
Departamento de Ingeniería Química
Universidad de Concepción, Chile

Many examples taken from separation technologies and from the development of fluid materials, allow us to conclude that key engineering processes depend on the phase behavior and properties of multicomponent rather than binary mixtures. In general, for the case of binary mixtures unlike molecules are free to interact with each other at the microscopic scale. Ternary mixtures, in contrast, provide a basic molecular system where unlike molecules compete for interactions at the molecular scale and, therefore, may be considered as a more realistic prototype of the interactions that occur in multi-component fluids. Experimental results in ternary systems shows us that some types of binary interactions are preferentially promoted (or inhibited) either by direct competence for the same functional groups or by steric hindrance among molecules of different shape and type. Hence, depending on the differences of their constituent molecules, ternary mixtures may exhibit specific phenomena that cannot be directly predicted by analyzing their binary interactions only. Significant progress has been obtained in the experimental determination and theoretical treatment of binary fluid mixtures, where solidly established molecular explanations have been provided for explaining the topology of their phase diagrams in excellent agreement with experimental results, theoretical models and molecular simulations. For the case of ternary mixtures, in contrast, although important progress has been made in direct measurements and experimental techniques, little research are available about their characterization in a wide range of temperature or pressure conditions. Engineering practice mainly relies on the prediction of the properties of these ternary mixtures by considering their inherent binary contributions, an approach that has successfully used for treating vapor-liquid equilibrium in the low- pressure range. However, these predictive results are not so promising -and usually require ex