Anabela J L Costa

Publications (3)7.11 Total impact

• Source

  Available from: Jose Nuno A Canongia Lopes

  Article: Liquid-liquid equilibrium of cholinium-derived bistriflimide ionic liquids with water and octanol.

  Anabela J L Costa, Mário R C Soromenho, Karina Shimizu, Isabel M Marrucho, José M S S Esperança, J N Canongia Lopes, Luís Paulo N Rebelo
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  ABSTRACT: The liquid-liquid equilibria of mixtures of cholinum-based ionic liquids (N-alkyl-N,N-dimethylhydroxyethylammonium bis(trifluoromethane)sulfonylimide, [N(11n2OH)][Ntf(2)], n = 1, 2, 3, 4, and 5) plus water or 1-octanol were investigated at atmospheric pressure over the entire composition range. The experiments were conducted between 265 and 385 K using the cloud-point method. The systems exhibit phase diagrams consistent with the existence of upper critical solution temperatures. The solubility of [N(1 1 n 2OH)][Ntf(2)] in water is lower for cations with longer alkyl side chains (larger n values). The corresponding trend in the octanol mixtures is reversed. The ([N(1 1 1 2OH)][Ntf(2)] + water + octanol) ternary system shows triple liquid-liquid immiscibility at room temperature and atmospheric pressure. A combined analytic/synthetic method was used to estimate the corresponding phase diagram under those conditions. Auxiliary molecular dynamics simulation data were used to interpret the experimental results at a molecular level.
  The Journal of Physical Chemistry B 07/2012; 116(30):9186-95. · 3.70 Impact Factor
• Source

  Available from: Jose Nuno A Canongia Lopes

  Article: Density, thermal expansion and viscosity of cholinium-derived ionic liquids.

  Anabela J L Costa, Mário R C Soromenho, Karina Shimizu, Isabel M Marrucho, José M S S Esperança, José N Canongia Lopes, Luís Paulo N Rebelo
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  ABSTRACT: Density and viscosity data of the N-alkyl-N,N-dimethyl-N-(2-hydroxyethyl)ammonium bis(trifluoromethylsulfonyl)imide ionic liquids homologous series [N(1 1 n 2(OH))][Ntf(2)] with n=1, 2, 3, 4 and 5 have been measured at atmospheric pressure in the 283<T/K<373 temperature range and the corresponding isobaric thermal expansion coefficients have been calculated. This work studies the effect of increasing the alkyl chain length of the cholinium-based cation on the density, viscosity and related properties of this family of ionic liquids. A volumetric predictive method based on the effective molar volume of cations and anions is used to estimate the effective molar volume of the different cations present in this study. The results agree with data for other cation families that show a molar volume increment per CH(2) group on the alkyl chain of the cation of about 17.2 cm(3) mol(-1), except for [N(1 1 1 2(OH))](+), which exhibits an outlier behaviour. Molecular dynamics simulation results are used to explain the volumetric behaviour along the homologous series from a molecular perspective. The predictive power of group contribution methods for density and viscosity is also tested.
  ChemPhysChem 02/2012; 13(7):1902-9. · 3.41 Impact Factor
• Article: Densities and Viscosities of 1-Ethyl-3-methylimidazolium n-Alkyl Sulfates

  Anabela J. L. Costa, José M. S. S. Esperança, Isabel M. Marrucho, Luís Paulo N. Rebelo
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  ABSTRACT: Density and viscosity data for four 1-ethyl-3-methylimidazolium-based ionic liquids combined with alkyl sulfate, [CnSO4]− with n = 1, 4, 6, and 8, and hydrogen sulfate, [HSO4]−, anions were measured at atmospheric pressure in the temperature range 283 < T/K < 363. Isobaric thermal expansion coefficients were calculated from the density results. This work studies the effect of increasing the alkyl chain length of the sulfate-based anion on the density, viscosity, and related properties of this family of ionic liquids. The effective volumes of the distinct anions used were calculated from the measured density values, simply by subtracting the effective volume of the cation already available from literature to the molar volume of the ionic liquid. We also evaluated the predictive ability of group contribution methods for density and viscosity. Since large deviations between the predictions and the experimental data occurred for both density and viscosity, new group contribution parameters were proposed. The results clearly show that [HSO4]− cannot be considered part of the [CnSO4]− family.
  07/2011;