n - PATh :.: Process and Product Applied Thermodynamics research ...

General Introduction
In 1996, a method based on molecular descriptors was proposed to predict a host of
unknown physicochemical properties of perfluoroalkanes (Gabriel et al., 1996). The input
parameters were categorized as empiric properties, geometric indices, or quantum
mechanical descriptors and then, individual algorithms were developed for each
independent variable function, namely, oxygen solubility, log P, vapour pressure, viscosity,
and density. Those algorithms were expected to assist in the prediction of the physical
properties of perfluoroalkane liquids, such that the design of new perfluoroalkanes and
selection from currently available perfluoroalkane liquids could be optimised for each
application (Gabriel et al., 1996).
Modelling of the thermodynamic properties of pure perfluoroalkanes and their
mixtures in an extended range of thermodynamic conditions is a recent research field.
Since 1998, essentially molecular simulation and different versions of the SAFT equation
of state (EoS) are being used to model perfluoroalkanes and their mixtures. Table I.3
resumes literature data available mentioning the method and the systems used by the
different authors. These works helped to elucidate some questions relating
perfluoroalkanes and their behaviour but new questions/discussions appeared and there are
still many aspects to elucidate.
This work intends to be a contribution in the effort devoted to the characterization
of perfluoroalkanes and their mixtures. Recent publications relating perfluoroalkanes
systems apply different approaches to describe their properties but the conclusions taken
cannot be generalized once experimental data is not available to confirm their accuracy and
applicability. The main objective is to complement/validate experimental data available in
the literature and also present new experimental data that, besides the practical direct
interest, can help to answer/validate the theories and models relating highly fluorinated
systems.
The thesis is organized in two parts. The first part deals with the experimental data
measured: density, vapour pressure, solubility of gases, namely oxygen at atmospheric
pressure and carbon dioxide at high pressure and liquid-liquid equilibrium for alkane +
perfluoroalkanes mixtures. The apparatus built to measure vapour pressure and oxygen
solubility data are presented as well as the experimental procedure used. Among the
studied perfluoroalkanes are the ones that are currently been used for the applications
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