Several physical properties were determined for the ionic liquid 3-methyl-N-butylpyridinium tri-cyanomethanide ([3-mebupy]C(CN)(3)): liquid density, viscosity, surface tension, thermal stability and heat capacity in the temperature range from (283.2 to 363.2) K and at 0.1 MPa. The density and the surface tension could well be correlated with linear equations and the viscosity with a Vogel-Fulcher-Tamman equation. The IL is stable up to a temperature of 420 K. Ternary data for the systems {benzene + n-hexane, toluene + n-heptane, and p-xylene + n-octane + [3-mebupy]C(CN)(3)} were determined at T=(303.2 and 328.2) K and p = 0.1 MPa. All experimental data were well correlated with the NRTL model. The experimental and calculated aromatic/aliphatic selectivities are in good agreement with each other. (C) 2011 Elsevier B.V. All rights reserved.