Thermophysical and spectroscopic study of molecular interactions in 1-butyl-3-methylimidazolium tetrafluoroborate + propyl acetate system at ambient temperatures: Experimental and theoretical approach

Abstract

The study presents the investigation of molecular interactions in blended mixtures of 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF4] + propyl acetate from the measurements of density, ρ and speed of sound, u of pure 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF4], propyl acetate and their mixtures across entire mole fraction range at temperature from 298.15 – 323.15 K with an interval of 5 K and at pressure, p = 100 kPa. The excess properties for the mixtures, partial molar properties (volume/compressibility), excess partial molar properties (volume/compressibility) of the components across entire mole fraction range; and at infinite dilution were been calculated. The excess molar volumes of these mixtures were predicted theoretically using PFP theory and the results were compared with experimental values. The density data of these mixtures was modelled using PC-SAFT model, whereas a number of models were applied to predict the speed of sound theoretically. Additionally, the FT-IR spectra of pure [BMIM][BF4], propyl acetate and their near equimolar mixture were recorded and examined to validate the nature and extent of dominant intermolecular interactions. © 2025