Browsing by Author "Rosini, Sabrina Barbosa"
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- Ionic liquids as entrainers for terpenes fractionation and other relevant separation problemsPublication . Vilas-Boas, Sérgio M.; Teixeira, Gabriel; Rosini, Sabrina Barbosa; Martins, Mónia A.R.; Gaschi, Priscilla S.; Coutinho, João A.P.; Ferreira, Olga; Pinho, SimãoThis work discusses the potential of two phosphonium-based ionic liquids (ILs), [P6,6,6,14]Cl and [P6,6,6,14][(C8H17)2PO2], and one methylimidazolium-based IL, [C4mim][OAc], as entrainers in the fractionation of terpene mixtures, in the desulfurization and denitrification of fuel oils, and in the separation of aromatics from aliphatic hydrocarbons. To this aim, the activity coefficients at infinite dilution of 45 solutes were obtained by gas-chromatography in the temperature range (333.15–458.15) K. Selectivities and capacities were calculated showing that [P6,6,6,14]Cl is adequate for the fractionation of (−)-menthone/L-(−)-menthol mixture, being also a suitable option for the deterpenation of citrus essential oil, and the removal of thiophene and pyridine from aliphatic hydrocarbons. To complement the experimental measurements COSMO-RS model was tested, demonstrating good potential to screen separation agents and give insights for several important separation problems, including the removal of contaminants from fuels and the isolation, fractionation and purification of terpenes mixtures.
- Ionic liquids for application in separation processes: chromatographic and calorimetric studiesPublication . Rosini, Sabrina Barbosa; Pinho, Simão; Ferreira, Olga; Priscilla, LeiteThe family of ionic liquids can provide safer, efficient and more sustainable alternative solvents than those commonly used. In this work, 1-butyl-3-methylimidazolium acetate (BmimAc) was the selected ionic liquid to be studied as a separation agent in different liquid-liquid extraction problems with terpenes and terpenoids. After separation, it is important to devise a strategy to recover the IL and minimize costs. To do so, infinite dilution activity coefficients of water and 44 solutes belonging to different families of organic compounds, were measured in the ionic liquid by gas chromatography. This ionic liquid showed strong interaction with polar solutes like alcohols and linalool, for which low values of activity coefficients at infinite dilution were obtained. Concerning the system limonene/linalool (compounds used in biodegradable solvents and perfumery industries), this IL showed the best values of capacity and selectivity, calculated through activity coefficients. However, it was not a good separation agent of the mixture α–pinene/β–pinene (used in used in medications with antifungal action). Besides that, the solid-liquid equilibria phase diagram was studied by differential scanning calorimetry (DSC), by measuring the freezing point depression of water caused by the addition of 1-butyl-3-methylimidazolium acetate. The methodology was tested first by measuring the freezing point of aqueous solutions of NaCl, CaCl2, 2-propanediol and 1-ethyl-3-methylimidazolium acetate (EmimAc). The values obtained in this work agreed with literature, except for the 1-ethyl-3-methylimidazolium acetate. So, further tests need to be carried out using other methodologies. Through the measurement of freezing point curves, important data were obtained concerning the 1-butyl-3-methylimidazolium acetate (BmimAc)+ water interactions. Thus, crystallization is a possible process for separating ILs from water. This work offers a solution to separate the system limonene/linalool and then recovery the IL through freezing point depression of water/BmimAc once that was possible freeze the water.