Study of thermophysical properties of the binary mixtures of ionic liquid 1-ethyl-3-methylimidazolium ethylsulfate and 2-propoxyethanol from T = (298.15 to 328.15) K at atmospheric pressure

• The studied binary system is {[Emim][EtSO4] + 2-propoxyethanol}.
• Density, speed of sound and refractive index are measured at various temperatures.
• Derived excess/deviation parameters indicated the existence of strong interactions.
• Geometrical fitting and hydrogen bonding explain the observed interactions.
• IR spectral studies also support the existence of strong interactions.

Experimental data for density (ρ), speed of sound (u) and refractive index (nD) for pure 1-ethyl-3-methylimidazolium ethyl sulfate ([Emim][EtSO4]), 2-propoxyethanol and their binary mixtures are measured over the whole composition range as a function of temperature between 298.15 and 328.15 K at atmospheric pressure. Experimental values are used to calculate the excess molar volumes (VmE), excess partial molar volumes (V‾mE), partial molar volumes at infinite dilution (V‾mE,∞), excess/deviation values of isentropic compressibility (κsE), free length (LfE), acoustic impedance (ZEZE), speeds of sound (uEuE), refractive index (ΔϕnDΔϕnD) and isobaric thermal expansion coefficient (αPE) for the binary mixtures. These excess/deviation properties are fitted to the Redlich–Kister type equation to obtain the coefficients and the standard deviations. The negative values of excess properties such as VmE, κSE, LfE, αPE and positive values of ZE  , uEuE, ΔϕnDΔϕnD indicate existence of strong interaction between studied components. A quantitative analysis of these parameters was further supported by IR spectroscopy analysis.

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