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The present work was aimed at investigating the usefulness of 1-(nalkyl)-3-methylimidazolium-derived ionic liquids (ILs) in liquid-liquid separation processes. For this purpose, a series of 1-(n-alkyl)-3-methylimidazolium tetrafluoroborates and hexafluorophosphates were prepared by standard synthetic methods and characterized by 1 H NMR. Experiments were performed to assess the influence of the alkyl group and the anion on the physical properties of the IL. Equilibrium studies on the extraction of heavy metal ions (copper, zinc, and chromium) and some common pollutant aromatic compounds (phenol, tyrosol, and p-hydroxybenzoic acid) from aqueous media then were performed with 2155 some selected ILs. The effects of temperature and the pH on the distribution ratio of solutes between the IL/aqueous phases also were analyzed. The results suggest that some of the ionic liquids tested are adequate to extract metal ions and organic compounds from aqueous solutions, with a high efficiency in some instances.

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Abstract:Biodiesel is the main alternative to fossil diesel and it may be produced from different feedstocks such as semi-refined vegetable oils, waste frying oils or animal fats. However, these feedstocks usually contain significant amounts of free fatty acids (FFA) that make them inadequate for the direct base catalyzed transesterification reaction (where the FFA content should be lower than 4%). The present work describes a possible method for the pre-treatment of oils with a high content of FFA (20 to 50%) by esterification with glycerol. In order to reduce the FFA content, the reaction between these FFA and an esterification agent is carried out before the transesterification reaction. The reaction kinetics was studied in terms of its main factors such astemperature, % of glycerin excess, % of catalyst used, stirring velocity and type of catalyst used. The results showed that glycerolysis is a promising pretreatment to acidic oils or fats (> 20%) as they led to the production of an intermediary material with a low content of FFA that can be used directly in thetransesterification reaction for the production of biodiesel. BORDADO, João Moura -Study on the glycerolysis reaction of high free fatty acid oils for use as biodiesel feedstock.