Ternary liquid-liquid equilibria for 3 systems containing ionic liquids (4-(2-methoxyethyl)-4-methylmorpholinium bis(trifluoromethylsulfonyl)-amide, 1-(2-methoxyethyl)-1-methylpiperidinium bis(trifluoromethylsulfonyl)-amide, 1-(2-methoxyethyl)-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)-amide) + thiophene + n-heptane have been determined at T = 298.15 K. All systems showed high solubility of thiophene in the ionic liquid and low solubility of n-heptane. The solute distribution coefficient and the selectivity were calculated for all systems. High selectivities were obtained. The experimental results have been correlated using NRTL model. The influence of cation structure on phase equilibria is discussed. (C) 2012 Elsevier B.V. All rights reserved.