Use of 1-alkyl-3-methylimidazolium hexafluorophosphate room temperature ionic liquids as chelate extraction solvent with 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione.

Possible use of room temperature ionic liquids (RTILs) as chelate extraction solvent was evaluated by using 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF(6)]), 1-hexyl-3-methylimidazolium hexafluorophosphate ([hmim][PF(6)]) and 1-octyl-3-methylimidazolium hexafluorophosphate ([omim][PF(6)]). These RTILs showed high extraction performance for divalent metal cations with 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (Htta). The extracted metals were back-extracted into 1moldm(-3) nitric acid quantitatively. Furthermore, the extracted species were estimated as neutral hydrated complexes M(tta)(2)(H(2)O)(n) (n= 1 or 2) for M = Ni, Cu and Pb and anionic complexes M(tta)(3)(-) for M = Mn, Co, Zn and Cd.