THERMODYNAMICS AND TOPOLOGICAL INVESTIGATIONS OF TERNARY MIXTURES CONTAINING IONIC LIQUID WITH ORGANIC SOLVENTS: EXCESS MOLAR VOLUMES AND EXCESS ISENTROPIC COMPRESSIBILITIES

Abstract

We report densities, ρ_ijk  and speeds of sound, u_ijk of 1-ethyl-3-methylimidazolium tetrafluoroborate (i) + water (j) + formamide or N,N- dimethylformamide (k) ternary mixtures over entire composition range at 293.15, 298.15, 303.15, 308.15 K. The heat capacities, Cpof 1-ethyl-3-methylimidazolium tetrafluoroborate, water, formamideand N,N- dimethylformamide have also been measured at 293.15, 298.15, 303.15, 308.15 K using micro differential scanning calorimeter (Model -µDSC 7 Evo). The measured ρ_ijk and u_ijk data have been utilized to determine their excess molar volumes, V_ijk^E and excess isentropic compressibilities, (κ^E_S) _ijk values. In this study, we have used the topology of the constituent mixtures (Graph theory) to determine E ijkV and ( ) E S ijk κ values of the investigated mixtures. Results obtained indicate that V^E _ijk and (κ^E_S)_ijk values determined by Graph theory compare well with their corresponding experimental values.The observed V^E_ijk , (κ^E_S)_ijk data have also been analyzed in terms of PrigogineFlory-Patterson theory.