Aqueous biphasic systems involving alkylsulfate-based ionic liquids

The specific effects of K3PO4, K2CO3, Na2CO3, and (NH4)(2)SO4, as high charge-density inorganic salts and thus inducers of the formation of aqueous biphasic systems (ABS) containing several ethyl-methylimidazolium alkylsulfate ionic liquids, C2MIM CnSO4(n = 2, 4, 6, or 8), have been assessed at T= 298.15K. The results are analyzed in the light of the Hofmeister series. The influence of different alkyl chain lengths in the anion, together with the ability of the selected inorganic salts to induce the formation of ABS, is discussed. Phase diagrams have been determined through turbidimetry, including tie lines assignments from mass phase ratios according to the lever - arm rule. The Merchuck equation was satisfactorily used to correlate the solubility curve. (C) 2011 Elsevier Ltd. All rights reserved.