Nucleo Of Estudos Em Sistemas Coloidais Itp Unit

Aracaju, Brazil

Nucleo Of Estudos Em Sistemas Coloidais Itp Unit

Aracaju, Brazil
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Santos D.,Federal University of Bahia | Lourenco E.,Nucleo Of Estudos Em Sistemas Coloidais Itp Unit | Santos M.F.C.,Federal University of Paraná | Franceschi E.,Nucleo Of Estudos Em Sistemas Coloidais Itp Unit | And 5 more authors.
Journal of Molecular Liquids | Year: 2016

Densities were determined for binary mixtures containing the protic ionic liquids: bis (2-hydroxyethyl) ammonium acetate, propionate, and butanoate ([BHEA][Ac], [BHEA][Pr], and [BHEA][Bu]) and water at six different temperatures (293.15, 303.15, 313.15, 323.15; 333.15, 343.15 K) and atmospheric pressure. The densities were fitted using the Mattedi-Tavares-Castier equation of state, which correlated the experimental data well. For the system bis (2-hydroxyethyl) ammonium butyrate + water, a maximum in density was observed at intermediate compositions, at each of the measured temperatures. The excess molar volumes were generally negative for the three binary systems studied, except for certain compositions at the highest measured temperatures. © 2016 Elsevier B.V.


Santos D.,Federal University of Bahia | Costa F.,Federal University of Bahia | Franceschi E.,Nucleo Of Estudos Em Sistemas Coloidais Itp Unit | Santos A.,Nucleo Of Estudos Em Sistemas Coloidais Itp Unit | And 2 more authors.
Fluid Phase Equilibria | Year: 2014

Over the years, ionic liquids have received increased attention in several fields of application. More specifically a new ionic liquid family was developed, called protic ionic liquids, that have been proven to be biodegradable and they have potentially low toxicity, besides their low cost of preparation, simple synthesis and purification are interesting features. Continuing with our systematic work on synthesis and characterization of protic ionic liquids, this work deals with the synthesis, FT-infrared identification and thermodynamic characterization of two new ionic liquids, 2-hydroxyethylammonium stearate, (2-HEAS) and bis(2-hydroxyethylammonium) stearate (B2HEAS), based in the neutralization reaction of stearic acid with 2-hydroxyethylamine and bis(2-hydroxyethylamine) (generally known as mono and diethanolamine, respectively). Thermal properties of ionic liquids in function of temperature and concentration, along with the volumetric properties were determined. Results showed that both ionic liquids (2-HEAS and B2HEAS) form micelles, suggesting interfacial activity. Also, low negative deviations from ideality for the two binary systems were observed. © 2014 Elsevier B.V.


Santos D.,Federal University of Bahia | Goes M.,Nucleo Of Estudos Em Sistemas Coloidais Itp Unit | Franceschi E.,Nucleo Of Estudos Em Sistemas Coloidais Itp Unit | Santos A.,Nucleo Of Estudos Em Sistemas Coloidais Itp Unit | And 3 more authors.
Brazilian Journal of Chemical Engineering | Year: 2015

In this work, the mutual solubilities of sets of ionic liquids ([CnMIM] [TF2N] (n = 4, 8, 12), [C4PY] [TF2N], [C8MIM] [OTF]) and organic compounds (heptane, o-xylene, toluene, or water) are investigated. The experimental data measured for these systems were used to adjust the binary interaction parameters between their components for the Non-Random Two Liquid (NRTL) model. The results showed that the solubility increased with temperature, with high hygroscopicity (10-1 in terms of mole fraction) of the ILs, low interactions with aliphatic hydrocarbons, high interactions with aromatic hydrocarbons and the presence of a lower critical solution temperature (LCST). In addition, this study is the first to show that [C12MIM] [TF2N] is completely soluble in toluene and ortho-xylene between 273.15 and 373.15 K at 1 bar. The average deviations related to the mole fraction between the experimental and calculated values by the NRTL were less than 2.4%.


Santos D.,Federal University of Bahia | Santos M.,Federal University of Paraná | Franceschi E.,Nucleo Of Estudos Em Sistemas Coloidais Itp Unit | Dariva C.,Nucleo Of Estudos Em Sistemas Coloidais Itp Unit | And 2 more authors.
Journal of Chemical and Engineering Data | Year: 2016

In this work are reported densities of protic and aprotic ionic liquids in a wide temperature range, at ambient pressure, and a thermodynamic modeling is performed through Mattedi-Tavares-Castier, the EOS is based on lattice gas theory. The results are quite satisfactory with deviations smaller than 0.05%. The densities of aprotic ionic liquids are presented with greater magnitudes compared to protic ILs, revealing significant differences between levels of cohesion and electrostatic contributions among the protic and aprotic ionic liquids. © 2015 American Chemical Society.

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