resumo
The solubility of ionic liquids (ILs) in water is of significant relevance for both process design and evaluation of their environmental impact. In this work, the solubilities of the non-aromatic piperidinium and pyrrolidinium-based ILs in water, combined with the anion bis(trifluoromethylsulfonyl)imide, were determined in the temperature range from (288.15 to 318.15) K. Electrospray ionization mass spectrometry (ESI-MS) was used as the analytical method after a proper validation of the experimental results obtained. The effect of the ILs structural combinations, such as cation family and alkyl side chain length, in their solubility in water, is analyzed and discussed. From the ILs solubility dependence on temperature, the standard molar thermodynamic functions of solution, namely Gibbs energy, enthalpy and entropy at infinite dilution, were determined. The results indicate that the ILs dissolution in water is an endothermic process and entropically driven. To predict the mutual solubilities between ILs and water, a quantitative structure-property relationship (QSPR) model is also proposed. It is shown that it can provide a good description of the mutual solubilities at 303.15 K with deviations smaller than 10%. (C) 2010 Elsevier B.V. All rights reserved.
palavras-chave
IONIZATION MASS-SPECTROMETRY; MUTUAL SOLUBILITIES; PHASE-BEHAVIOR; ORGANIC-SOLVENTS; ELECTROSPRAY; CATIONS; THERMODYNAMICS; EQUILIBRIA; TOXICITY
categoria
Thermodynamics; Chemistry; Engineering
autores
Freire, MG; Neves, CMSS; Ventura, SPM; Pratas, MJ; Marrucho, IM; Oliveira, J; Coutinho, JAP; Fernandes, AM
nossos autores
Catarina Maia Seco Seiça Neves
Investigador Auxiliar
Isabel Maria Delgado Jana Marrucho Ferreira
Professor Catedrático
Mara Guadalupe Freire Martins
Investigador Coordenador
Maria Jorge Pratas
Gestor de Ciência e Tecnologia
Sónia Patrícia Marques Ventura
Professor AuxiliarGrupos
G4 - Materiais Renováveis e Economia Circular
G5 - Materiais Biomiméticos, Biológicos e Vivos
agradecimentos
The authors thank financial support from Fundacao para a Ciencia e a Tecnologia: project PTDC/EQU-FTT/65252/2006 and PhD grants SFRH/BD/28258/2006 and SFRH/BD/37830/2007 from M.J.P. and S.P.M.V., respectively.