(179c) Techniques for Measuring and Modeling Thermodynamic and Transport Properties of Ionic Liquids Saturated with Compressed Gases

Numerous engineering applications involving mixtures of ionic liquids and gases have been proposed in the literature. Feasibility and applicability of such mixtures require proper knowledge of thermodynamic and transport behavior of each respective pure component as well as the solution. Here, techniques for measuring thermodynamic and transport properties including global phase behavior, solubility, density, viscosity, self-diffusivity and thermal conductivity are presented. This study emphasizes the need for accurate data on mixture properties as simple weight/mole average approximations often lead to highly erroneous values. Additionally, assessments of the ramifications on unit design resulting from invalid simple predictive models for predicting the aforementioned properties are presented. Semi-empirical modeling techniques with extended applicability are proposed for increased accuracy in predicting mixture properties of biphasic ionic liquid-gas mixtures. Systems investigated in this work include imidazolium-based ionic liquids saturated with various gases ‒ carbon dioxide, ammonia, difluoromethane, pentafluoroethane, and 1,1,1,2-tetrafluoethane ‒ at temperatures between 298.15K and 398.15K and pressures up to 200 bar.