Salting-out Phase Separation System of Water–Tetrahydrofuran with Co-using 1-Butyl-3-methylimidazolium Chloride and Sodium Chloride for Possible Extraction Separation of Chloro-complexes

Abstract

The salting-out phase separation behavior of the water–tetrahydrofuran (THF) homogeneous system with co-adding a hydrophilic ionic liquid, 1-butyl-3-methylimidazolium chloride ([C₄mim]Cl), and NaCl was investigated. In the water–THF/[C₄mim]Cl biphasic system, the lower phase showed a relatively large volume and low polarity compared with that in the water–THF/NaCl system, because of the coexistence of THF and [C₄mim]Cl. In the water–THF/[C₄mim]Cl–NaCl mixed salting-out agent system, the lower phase polarity depended on the composition of the salting-out agents. Furthermore, the distribution behavior of Fe(III)– and Zn(II)–chloro complexes in the mixed salting-out agent system was investigated to show the potential for application of the system for the extraction separation of metals as their chloro-complexes.