Springer Verlag, Monatshefte für Chemie - Chemical Monthly, 11(138), p. 1153-1157
DOI: 10.1007/s00706-007-0721-3
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Changes of the fluid phase behaviour of polyeth-ylene glycol (PEG) aqueous solutions – viz. critical solution temperature shifts at atmospheric pressure – were produced by the addition of different ionic liquids, namely 1-ethyl-3-methylimidazolium ethyl sulfate and 1-alkyl-3-methylimida-zolium chloride (alkyl ¼ ethyl to decyl). The addition of ionic liquids with long alkyl chains improves the solubility of PEG in water (salting-in effect), whereas the impact of short-chain ionic liquids is usually the contrary (salting-out effect). The results are interpreted taking into account the kosmotropic (water-structuring) or chaotropic (water-structure-breaking) nature of ionic liquids, as compared to other inorganic salts.