Alternative solvents in separation processes

Dissertation presented to obtain the Ph.D degree in Sustainable ChemistryFundação para a Ciência e Tecnologia - through doctoral fellowship SFRH/BD/45323/2008, and grant No Pest-C/EQB/LA0006/2011; partially supported from the Conselho de Reitores das Universidades Portuguesas (CRUP) – Integrated project Portugal-Spain, No E-95/10

Solubility of erythromycin in ionic liquids

(Solid + liquid) and (liquid + liquid) phase equilibria of binary mixtures containing various ionic liquid and erythromycin were studied. The solubility of erythromycin in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, or 1-decyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, or trihexiltertadecilphosphonium chloride, or butyltrimethylammonium bis(trifluoromethylsulfonyl)imide, or methyltrioctylammonium bis(trifluoromethylsulfonyl)imide, or 1-butyl-1 -methyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide has been measured by a dynamic method, in a wide range of temperatures from (284 to 358) K, at atmospheric pressure. The activity coefficients of erythromycin in ionic liquids were calculated and their comparison with ideal solution was discussed. The experimental data were correlated successfully by means of the semi-empirical Grant equation

Trihexyl(tetradecyl)phosphonium bromide:liquid density, surface tension and solubility of carbondioxide

Vapour-liquid equilibria of ionic liquid - carbon dioxide systems, as well as thermo-physical properties of the system components are very important to design and optimize various separation and reaction processes. In this work the solubility of carbon dioxide (CO2) in trihexyl(tetradecyl)phosphonium bromide([THTDP][Br]) was measured using a high-pressure sapphire cell, in pressure range of 8-22 MPa and at two temperatures, 313.2 K and 323.2 K. The thermophysical properties, namely liquid density and surface tension of the ionic liquid were determined in temperature range of 293.2-343.2 K. The densities predicted by Gardas and Coutinho model showed good agreement with the experimental data obtained in this work. The critical temperature of [THTDP][Br] was estimated using the Eotvos correlation. Moreover, these experimental and calculated data gave an opportunity to apply the Peng-Robinson equation of state (PR-EoS) in order to predict/correlate the behaviour of the studied system, ([THTDP][Br] + CO2) with satisfactory results. (C) 2012 Published by Elsevier B.V

Recovery of erythromycin from aqueous solutions with an ionic liquid and high-pressure carbon dioxide

Recovery of erythromycin from aqueous solutions was studied in two steps: (i) single- and multi-stage extraction of erythromycin from an aqueous solution with a hydrophobic ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide [BMPyrrol][Tf(2)N], as a function of pH and feed to solvent volume ratio, and (ii) high-pressure CO(2) extraction of erythromycin from the ionic liquid, as a function of pressure, temperature and presence of water. Furthermore, data on the mutual solubilities of the hydrophobic ionic liquid and water, as well as on the solubility of erythromycin in [BMPyrrol][Tf(2)N], were obtained. The chemical stability of erythromycin in water-free and water saturated ionic liquid was tested. These results allowed the evaluation of the coupling of liquid-liquid and high-pressure CO(2) extractions. (C) 2011 Elsevier B.V. All rights reserved

High-pressure solubilities of carbon dioxide in ionic liquids based on bis(trifluoromethylsulfonyl)imide and chloride

In this work, the solubility of carbon dioxide (CO2) in seven different ionic liquids (ILs) was measured using a high-pressure sapphire cell, in the pressure range of 8-22 MPa and at two temperatures, 313.2 K and 323.2 K. In order to discuss the influence of the cation, ILs based on bis(trifluoromethylsulfonyl)imide. [NTf2] were chosen. They were coupled with 1-butyl-3-methylimidazolium, [C(4)mim](+), 1-decyl-3-methylimidazolium, [C(10)mim](+), 1-butyl-methylpyrrolidinium, [Pyrr(4,1)](+), butyltrimethylammonium, [N-4,N-1,N-1,N-1](+), methyltrioctylammonium, [N-1,N-8,N-8,N-8](+) and trihexyltetradecylphosphonium, [P-6,P-6,P-6,P-14](+)cation. The phosphonium based cation was also combined with chloride, [Cl](-), giving an opportunity to discuss the influence of an anion as well. The solubility data obtained in this work were used to evaluate the importance of explicitly including association for describing such systems. For that purpose, we compared the solubility modelling results from two cubic equations of state (Peng-Robinson and Soave-Redlich-Kwong) with those from the Cubic Plus Association Equation of State (CPA EoS) using different association schemes for the ionic liquids. We found that for such systems there is no major advantage in considering ILs as associating components. (c) 2012 Elsevier B.V. All rights reserved

Liquid-liquid equilibria of mixtures with ethyl lactate and various hydrocarbons

Mutual miscibility in mixtures containing ethyl lactate and various hydrocarbons (alkanes, alkenes, cyclohexane, alkyl cyclohexanes and terpenes) were explored in a range of temperatures from (273.2 to 320.9) K and at atmospheric pressure. Thus, the respective temperature-composition phase diagrams were constructed. The influence of temperature, aliphatic chain length and of double bond presence on liquid phase behavior was discussed. The obtained liquid-liquid solubility data were represented using the UNIQUAC-based model which showed to be an appropriate tool for representing the liquid-liquid behavior of (hydrocarbon + ethyl lactate) mixtures. (C) 2012 Elsevier B.V. All rights reserved

Acute viral meningitis in children

Catedra Boli Infecţioase FECMF „Nicolae Testemiţanu” Spitalul Clinic de Boli Contagioase la CopiiThe study comprised a number of 158 children with acute viral meningitis aged between1 and 17 years. The clinical picture of acute viral meningitis was dominated by triad: fever, headache, meningian irritation have been associated with some particulars depending on the clinical etiology. Disease evolution was favorable in 100% cases, convalescence from the 7-10 day. Studiul a cuprins un număr de 158 copii cu meningită acută virală cu vîrsta cuprinsă între 1 şi 17 ani. Tabloul clinic al meningitei acute virale a fost dominat de triada: febră, cefalee, semne de iritaţie meningiană, la care s- au asociat unele particularităţi clinice în funcţie de etiologie. Evoluţia maladiei a fost favorabilă în 100% cazuri, cu instalarea convalescenţei la a 7-10- a zi

Solubility of high-value compounds in ethyl lactate:measurements and modelling

(Solid + liquid) equilibria of binary mixtures containing high-value compounds and ethyl lactate were studied. Using the gravimetric method, the solubility of various solutes such as caffeine, vanillic acid, ferulic acid, caffeic acid and thymol in ethyl lactate was measured as a function of temperature over the range of (298.2 to 343.2) K, at atmospheric pressure. The differences in solubility of a given solute in water-saturated and dry ethyl lactate were observed. The deviation of these binary systems from ideal mixture behaviour was discussed. In order to understand the solubilization process, melting properties of pure solutes were determined by differential scanning calorimetry (DSC). The solubility data obtained were represented using UNIQUAC and UNIFAC-based models as well as with the Cubic-Plus-Association (CPA) equation of state. The results of the modeling indicate that these models are the appropriate tools for representing the solubility behaviour of various solutes in ethyl lactate. (C) 2011 Elsevier Ltd. All rights reserved

Liquid–liquid equilibria of imidazolium ionic liquids having bistriflamide or triflate anions with aromatic non-polar and polar compounds

Liquid–liquid equilibria (LLE) of the solutions of imidazolium ionic liquids having bistriflamide [NTf2]− and triflate [OTf]− anions with non-polar (benzene, toluene and p-xylene) and polar aromatic compounds (nicotine and aniline) were investigated. The respective temperature-composition phase diagrams were obtained at 0.1 MPa and in a temperature range 273.15 K–423.15 K. The diagrams posses the features already established for the systems of this type: (i) for the same anion, the mutual solubility continuously increases as the cation alkyl chain extends; (ii) the mutual solubility of the imidazolium ionic liquids having bistriflamide [NTf2]− anion is higher compared to that when the triflate [OTf]− anion is present; (iii) the solubility is reduced as the alkylation of the benzene ring increases. However, the LLE results for the solutions [Cnmim][OTf] + nicotine/or aniline) demonstrate a very sudden effect of the cation chain length on the liquid phase behavior. In particular, the addition of only two CH2 groups to the chain drastically increases the mutual solubility making the respective solutions always homogeneous. The experimental liquid–liquid equilibria (LLE) data for the [C2mim][OTf] + aniline, [C4mim][OTf] + aniline, and [C2mim][OTf] + nicotine systems were modeled using the UNIQUAC equation. The agreement of calculated compositions with experimental data is very satisfactory