Thermodynamic studies embracing molecular interactions between ionic liquids (ILs) and molecular solvents are scarce and are required to explore molecular interactions and structural effects with interest in engineering applications. Ammonium-based are interesting ILs since they can be tailored to provide information concerning both chain length and solvophobic/solvophilic effects. In this work from accurately measured density and sound speed data in the systems ethanol + {[N-4111]; [N-4441] or [choline]} [NTf2] derived quantities such as excess partial molar volumes and isentropic compressions including their limiting values were obtained. The reasoning of the results permitted to conclude that while in the [N-4441][NTf2] case packing effects due to the difference in size of the components prevail, in the other two cases specific interaction ethanol-cation explains both the lower minimums in the excess properties and the higher magnitude of the negative limiting excess partial molar, volumes and isentropic compression values in the mixture containing [N-4111][NTf2] in relation to [N-4441][NTf2] and the negative limiting partial molar isentropic compression in the [choline][NTf2] case in contrast with positive values for the other two ILs. (C) 2016 Elsevier Ltd.