Elucidation of molecular interactions in the mixtures of benzylalcohol with (C2–C4) alkylacetates through volumetric, ultrasonic, theoretical and ATR-FTIR spectroscopic studies at T = (298.15, 303.15, 308.15 and 313.15) K

Abstract

The molecular interactions in the binary mixtures of benzylalcohol (BnOH) with ethylacetate (EA), n-propylacetate (PA) and n-butylacetate (BA) have been analyzed using the experimental densities (ρ) and speeds of sound (u) over the whole range of composition at T=(298.15, 303.15, 308.15 and 313.15) K under atmospheric pressure. From the measured density and speed of sound data, the excess volumes (VE), excess isentropic compressibilities (κsE), excess partial molar volumes (Vi¯E) and excess partial molar volumes at infinite dilution (V¯iE,∞) for the said binary mixtures have been computed. The studied excess thermodynamic properties for the binary mixtures were found to be negative over the entire range of composition and at all the specified temperatures. The results have been interpreted in terms of formation of the intermolecular hydrogen bonds between component molecules, interstitial accommodation and structural factors ensuing in the binary mixtures. Further, Redlich-Kister and Hwang equations were fitted to the excess functions in order to derive the fitting parameters. Moreover, the experimental speed of sound data was correlated with two theoretical models namely free length theory (FLT) and collision factor theory (CFT). In addition, the experimental excess volumes (VE) have been used to test the applicability of the Prigogine–Flory–Patterson (PFP) theory to the studied binary mixtures. Likewise, attenuated total reflection Fourier transform infrared (ATR-FTIR) spectra for these binary systems have been recorded at equimolar composition to elucidate the intermolecular hydrogen bonding between component molecules. A good correlation is observed between excess thermodynamic parameters and ATR-FTIR studies.