Phase behavior of aqueous two-phase systems composed of 1-alkyl-3-methylimidazolium bromide + Rb2CO3/Cs2CO3 + water

•ATPS of ionic liquids + Rb2CO3/Cs2CO3 + H2O.•The binodal curves were fitted using a three-parameter equation.•The tie-lines were correlated by the Othmer–Tobias and Bancroft equations.•The different effecting factors on the ATPS were investigated.

This work was devoted to propose a series of novel aqueous two-phase systems (ATPSs) composed of 1-alkyl-3-methylimidazolium bromide + Rb2CO3/Cs2CO3 + water ([C2mim]Br = 1-ethyl-3-methylimidazolium bromide, [C3mim]Br = 1-propyl-3-methylimidazolium bromide, [C4mim]Br = 1-butyl-3-methylimidazolium bromide, [Amim]Br = 1-allyl-3-methylimidazolium bromide). The phase behavior of these ATPSs had been experimentally determined at T = 288.15 K < T < 308.15 K. In particular, the effects of the ionic liquid structure, temperature and the types of inorganic salts on the phase equilibrium of ATPSs have been discussed in detail. The binodal curves were fitted by a three-parameter equation. The tie-lines were correlated by the Othmer–Tobias and Bancroft equations.

Graphical abstractThe phase behavior for a series of aqueous two-phase systems composed of 1-alkyl-3-methylimidazolium bromide + Rb2CO3/Cs2CO3 + water had been experimentally determined in the temperature range of 288.15–308.15 K.Figure optionsDownload full-size imageDownload as PowerPoint slide