resumo
In this work, the ability of Na(2)SO(4) and ionic liquids to induce the formation of acidic aqueous two-phase systems (ATPS) is investigated. Ternary phase diagrams, tie lines, and tie-line lengths for several systems were determined and reported at 298 K and atmospheric pressure. It is here shown that among the ionic liquids studied only those containing long alkyl side chains at the ions and/or anions with low hydrogen bond basicity are capable of undergoing liquid-liquid demixing in the presence of Na(2)SO(4) aqueous solutions. The results obtained indicate that, besides the salting-out ability of the inorganic salt, the pH of the aqueous solution plays a crucial role toward the formation of ionic-liquid-based ATPS. In acidic media the range of ionic liquids that are able to undergo ATPS formation is substantially reduced when compared to alkaline aqueous salt solutions. The use of inorganic salts and ionic liquids to promote acidic ATPS is envisaged as particularly valuable in the extraction of compounds that exhibit low acid dissociation constants.
palavras-chave
BIPHASIC SYSTEMS; 1-BUTYL-3-METHYLIMIDAZOLIUM BROMIDE; MUTUAL SOLUBILITIES; 298.15 K; EXTRACTION; SALTS; WATER; SEPARATION; EQUILIBRIA; PYRIDINIUM
categoria
Chemistry
autores
Claudio, AFM; Ferreira, AM; Shahriari, S; Freire, MG; Coutinho, JAP
nossos autores
Ana Filipa M. Cláudio
Bolseiro de pós-Doutoramento
Ana Maria da Conceição Ferreira Takahashi
Investigador Júnior
Mara Guadalupe Freire Martins
Investigador CoordenadorGrupos
G4 - Materiais Renováveis e Economia Circular
G5 - Materiais Biomiméticos, Biológicos e Vivos
agradecimentos
A.F.M.C. and M.G.F. acknowledge Fundacao para a Ciencia e a Tecnologia for the doctoral grant SFRH/BD/74503/2010 and the postdoctoral grant SFRH/BPD/41781/2007, respectively.