Volumetric Properties of the Dilute Solutions of Imidazolium-Based Ionic Liquids in Butan-2-ol or Butan-2-one

Volumetric properties for ten binary mixtures, containing N3-substituted 1-methylimidazolium chloride ionic liquids, [C n mim][C l ] ( n = 0, 1, 2, 4, 6) and butan-2-ol or butan-2-one investigated in the molality range of ionic liquids ( m = 0.005–0.1 mol·kg −1 ), and in temperature range T = (278.15–313.15 K) at 5 K intervals. From measured density data, the thermal expansion coefficient, α_p , apparent molar volume, V_ϕ , partial molar volumes for solvent, V_1 and solute, V_2 , apparent molar volume at infinite dilution, V_ϕ^o , Masson’s interaction coefficient, S v , Heppler’s coefficient, ( ∂^2 V_ϕ^o/∂ T^2)_p , and limiting apparent molar expansibility, E_ϕ^o , were calculated. Masson’s equation satisfactorily correlated with the calculated data. Based on the S v coefficient, the interactions between cation and anion of the ionic liquids with butan-2-ol or butan-2-one are discussed. Ionic liquids [C 0 mim][C l ], [C 4 mim][C l ], and [C 6 mim][C l ] have structure-making properties, while [C 1 mim][C l ] and [C 2 mim][C l ] are structure-breakers in butan-2-ol. In butan-2-one solvent, the ionic liquid [C 0 mim][C l ] is a structure-breaker, while the other ionic liquids are structure-makers.