Surface tension of binary mixtures of imidazolium and ammonium based ionic liquids with alcohols, or water: Cation, anion effect

The surface tensions were measured at atmospheric pressure, with use of a ring tensiometer, of a series of alcoholic solutions of closely related ionic liquids: 1-methyl-3-methylimidazolium methylsulfate, [MMIM][CH 3SO 4] in alcohol (methanol, or ethanol, or 1-butanol at 298.15 K), 1-butyl-3-methylimidazolium methylsulfate, [BMIM][CH 3SO 4] in alcohol (methanol, or ethanol, or 1-butanol at 298.15 K), 1-butyl-3-methylimidazolium octylsulfate, [BMIM][OcSO 4] in alcohol (methanol, or 1-butanol at 298.15 K) and of 1-hexyloxymethyl-3-methylimidazolium tetrafluoroborate, [C 6H 13OCH 2MIM][BF 4], 1,3-dihexyloxymethylimidazolium tetrafluoroborate, [(C 6H 13OCH 2) 2IM][BF 4] in alcohol (methanol, or 1-butanol, or 1-hexanol at 308.15 and 318.5 K) and hexyl(2-hydroxyethyl)dimethylammonium bromide, C 6Br in 1-octanol at 298.15 K. The set of ammonium ionic liquids of different cations and anions (C 2Br, C 2BF 4, C 2PF 6, C 2N(CN) 2, C 3Br, C 4Br and C 6Br) was chosen to show the influence of small amount of the ammonium ionic liquid on the surface tension of water at 298.15 K. The influence of the cation, or anion alkyl chain length on the properties under study (densities and surface tension) was tested.