Thermodynamic study of the surface of liquid mixtures containing pyridinium-based ionic liquids and alkanols

• Surface tensions of a pyridinium ionic liquid with an alkanol have been determined.
• From experimental data surface tension deviations have been obtained and correlated.
• Relative adsorptions of alkanol at the (air + liquid) interface were also calculated.
• The relative adsorptions were found positive in all the mixtures.

Surface tension for seven binary mixtures containing a pyridinium-based ionic liquid (1-propylpyridinium tetrafluoroborate, 1-butylpyridinium tetrafluoroborate, 1-butyl-3-methylpyridinium tetrafluoroborate, or 1-butyl-4-methylpyridinium) and a short chain alkanol (methanol or ethanol) were determined at the temperatures: (293.15, 303.15, 313.15, and 323.15) K. From these data, the surface tension deviations were calculated. These deviations were correlated using a Redlich–Kister polynomial expansion. Moreover, relative adsorptions of alkanol at the (air + liquid) interface were calculated from the Gibbs isotherm.

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