Mixtures of hydrophobic and hydrophilic ionic liquids and use thereof in liquid ring compressors

A mixture of ionic liquids comprising

• at least one ionic liquid ILa which is completely miscible with water at 20° C. and 1013 mbar and
• at least one ionic liquid ILb which has a miscibility gap with water at 20° C. and 1013 mbar;
• wherein the cations of the ionic liquids ILa and ILb are selected from among compounds of the formula (IV.e)
• and oligomers comprising these structures, where
• R is hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, polycyclyl, heterocycloalkyl, aryl or heteroaryl,
• radicals R1, R2, R3 and R4 which are bound to a ring carbon atom are each, independently of one another, hydrogen, a sulfo group, COOH, carboxylate, sulfonate, acyl, alkoxycarbonyl, CO(NE1E2), cyano, halogen, hydroxyl, SH, nitro, NE3E4, alkyl, alkoxy, alkylthio, alkylsulfinyl, alkylsulfonyl, alkenyl, cycloalkyl, cycloalkyloxy, cycloalkenyl, cycloalkenyloxy, polycyclyl, polycyclyloxy, heterocycloalkyl, aryl, aryloxy or heteroaryl, where E1, E2, E3 and E4 are each, independently of one another, hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl,
• the radical R1 which is bound to a ring heteroatom is hydrogen, a sulfo group, NE1E2, sulfonate, alkyl, alkoxy, alkenyl, cycloalkyl, cycloalkenyl, polycyclyl, heterocycloalkyl, aryl or heteroaryl, where E1 and E2 are each, independently of one another, hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl, or
• two adjacent radicals R1 to R4 together with the ring atoms to which they are bound may also be at least one fused-on, saturated, unsaturated or aromatic ring or a ring system having from 1 to 30 carbon atoms, where the ring or the ring system can have from 1 to 5 nonadjacent heteroatoms or heteroatom-comprising groups and the ring or the ring system can be unsubstituted or substituted,
• where two geminal radicals R1 to R4 may together also be ═O, ═S or ═NRb, where Rb is hydrogen, alkyl, cycloalkyl, aryl or heteroaryl,
• the radicals R, R1, R2, R3 and R4 can alternatively be alkanediyl, cycloalkanediyl, alkenediyl or cycloalkenediyl which links a cation of one of the formula (IV.e) to a further cation of the formula (IV.e);
• where these radicals additionally function, via their second point of bonding, as radical R, R1, R2, R3 or R4 of said further cation, and said radicals alkanediyl, cycloalkanediyl, alkenediyl and cycloalkenediyl are optionally branched, substituted and/or interrupted by at least one heteroatom or a heteroatom-comprising group;
• where the anions of the at least one ionic liquid ILa are selected from among sulfates, sulfonates and carboxylates of the general formulae:
• RcOSO3—, RcSO3— and RcCOO—;
• where Rc is hydrogen, C1-C4-alkyl or C3-C7-cycloalkyl.