Salting-out effects in aqueous ionic liquid solutions: cloud-point temperature shifts.
The effects of the addition of three inorganic salts, namely, NaCl, Na(2)SO(4), and Na(3)PO(4), on the liquid-liquid (L-L) phase diagram of aqueous solutions containing the model ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate, [bmim][BF(4)], were investigated. All three inorganic salts trigger salting-out effects, leading to significant upward shifts of the L-L demixing temperatures of the systems. The magnitude of the shifts depends on both the water-structuring nature of the salt and its concentration; that is, the effects are correlated with the ionic strength of the solution and the Gibbs free energy of hydration of the inorganic salt. The pH effect and the occurrence of salt precipitation in concentrated solutions are also discussed.
Trindade
Joana R
JR
Instituto de Tecnologia Química e Biológica, ITQB2, Universidade Nova de Lisboa, Av. República, Apartado 127, 2780-901 Oeiras, Portugal.
Visak
Zoran P
ZP
Blesic
Marijana
M
Marrucho
Isabel M
IM
Coutinho
João A P
JA
Lopes
José N Canongia
JN
Rebelo
Luis P N
LP
D001881:Borates / Q000737:chemistry*; D005591:Chemical Fractionation; D007093:Imidazoles / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D044367:Phase Transition; D010710:Phosphates / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry*; D012995:Solubility; D012996:Solutions / Q000737:chemistry; D013431:Sulfates / Q000737:chemistry*; D013696:Temperature; D014867:Water / Q000737:chemistry
C419324:1-butyl-3-methylimidazolium tetrafluoroborate; D001881:Borates; D007093:Imidazoles; D052578:Ionic Liquids; D010710:Phosphates; D012996:Solutions; D013431:Sulfates; D014867:Water; C012036:sodium sulfate; D012965:Sodium Chloride; C018279:sodium phosphate