Effect of Some Imidazolium-Based Ionic Liquids with Different Anions on the Thermodynamic Properties of Acetaminophen in Aqueous Media at T = 293.15 to 308.15 K

In this work, the effect of two imidazolium-based ionic liquids with different anions, 1-butyl-3-methylimidazolium bromide, [BMIm]Br, and 1-butyl-3-methylimidazolium chloride, [BMIM]Cl, on thermodynamic properties of acetaminophen was investigated. For this purpose, measurement of density ρ speed of sound u and specific electrical conductivity κ for acetaminophen in aqueous solutions of ionic liquid was made at T = 293.15 to 308.15 K and at atmospheric pressure. The standard partial molar volumes V ϕ 0, partial molar isentropic compressibility K ϕ 0, hydration number n H, and Hepler’s constants (∂ 2 V ϕ 0 /∂ T 2 ) P have been calculated from the density and speed of sound data. The limiting molar conductivities Λ 0 and ion association constants K A for the ionic liquids in aqueous solutions of acetaminophen have been estimated using the low concentration chemical model (lcCM). The results confirm presence of a strong attractive interaction between acetaminophen molecules and the ionic liquids which that becomes stronger with increase in anion size.