Medição da solubilidade de gases em líquidos iónicos com microbalança de cristais de quartzo
authors Maria Jorge Pratas
supervisors Isabel Marrucho e João ABP Oliveira
thesis type Master in Instrumental Methods and Analytical Quality Control
nationality International
author keywords ionic liquids, solubility, gases, crystal quartz microbalance
abstract Room temperature ionic liquids, or simply ionic liquids, are relatively recent compounds which have been generating great expectations mainly related to the fact that their properties can be finely tunned depending on a criterious combination of the cation and the anion. One of the potential future applications is their use as green solvents, replacing the volatile organic solvents that are hazardous for the environment. Apart from their applications in areas such as chemistry, chemical engineering and the environmental sciences, it is foreseen that also they will have a large impact in areas as biotechnology, biochemist, pharmaceutical sciences, etc. The characterization of these new compounds in therms of their thermophysical properties as pure compounds or in mixtures is fundamental in order to select which ionic liquid provides the best choice for a specific application, The main goal of this work is to study the solubility of gases in ionic liquids in order to further contribute for the characterization of these compounds. The method adopted was a Quartz Crystal Microbalance and the constructed apparatus operates at pressures bellow the atmospheric pressure and temperatures between 283 and 333 K. The main advantage of this method is the short equilibration time, while maintaining the same precision and accuracy of the conventional methods used to measure the solubilities of gases in liquids. It is shown that the major limitation of the use of the Quartz Crystal Microbalance to quantitativelly measure the gas solubility in ionic liquids is the immobilization of the ionic liquids on the quartz crystal surface. Several methods of deposition were tested are the difficulties felt in each of them are discussed.
year published 2007