Filipe S. Oliveira

Inorganic salts in purely ionic liquid media: the development of High Ionicity Ionic Liquids (HIILs).

This work explores the possibility of increasing the ionicity of ionic liquids via the solubilization of inorganic salts in their midst. The resulting purely ionic media-distinct ionic liquid plus inorganic salt mixtures-are liquid in an extensive concentration range and can be aptly denominated High Ionicity Ionic Liquids (HIILs).

Deep eutectic solvents as extraction media for azeotropic mixtures

The separation of azeotropic mixtures is an “old” engineering problem that cannot be solved by simple distillation processes. One of the current ways to overcome this problem is to use other types of processes, such as extractive/azeotropic distillation or liquid–liquid extraction, where entrainers or extraction solvents are applied. Liquid–liquid extraction processes have been emerging as appealing alternatives because they do not require high amounts of energy, volatile organic compounds or high pressures. In this work, deep eutectic solvents (DES) are tested as extraction solvents in the liquid–liquid separation of azeotropic mixtures. For this study three different DES, all based on choline chloride, were used for the liquid–liquid separation of an azeotropic mixture of heptane + ethanol at 25 °C. The feasibility of DES as extraction solvents was assessed by the determination of their selectivities and distribution coefficients, and compared with the literature. The data obtained show that DES surpass the performance of existing extraction solvents, leading to an increase in efficiency and a reduction in energy consumption of the overall process.

Synthesis, Characterization, and Liposome Partition of a Novel Tetracycline Derivative Using the Ionic Liquids Framework

Recently, efforts have been put on the development of new drug formulations using ionic liquid framework. In this work, two different species of abroad-spectrum polyketide antibiotic, tetracycline, are studied in terms of some important properties for antibiotics such as solubility in water and hydrophilic-hydrophobic balance. Tetracycline was used as cation, whereas docusate, a biocompatible anion, which enables the tailoring of the hydrophilicity of salts, was chosen as the anion. The developed innovative ion pair, tetracycline docusate, was characterized in terms of its thermal stability, water solubility, octanol-water, and liposome-water partition coefficients, using UV-vis spectrophotometry because of the absorbance of tetracycline around 270 nm. Egg yolk phosphatidylcholine liposomes were used as cell membrane models, and the interactions of both tetracycline hydrochloride and tetracycline docusate with the liposomes were quantified by determination of the partition coefficient using derivative spectrophotometry. A theoretical model based on simple partition drugs between two different media was used to determine the partition coefficient in liposomes.