Correlation and modelling the thermodynamics properties of mixtures containing zinc (II) chloride-based deep eutectic solvent and alkanols with PC-SAFT EoS, and the Nomoto’s relation

Abstract

In this work, the thermophysical characteristics of binary mixtures including alkanols and a deep eutectic solvent (DES) based on zinc (II) chloride (ZnCl2) were examined. Densities (ρ), and speed of sounds (u) of binary mixtures of [ZnCl2][acetic acid] 1:4 with methanol, ethanol, and propanol were measured at temperature between (293.15---313.15) K and at atmospheric pressure. DESs have attracted a lot of researchers because of their unique properties and prospective uses in various fields. The focus of this research was to better understand the behaviour of binary mixtures composed of ZnCl2-based DES and alkanols, with an emphasis on their thermo-physical properties. Thermodynamic properties such as excess molar volumes, isentropic compressibilities, deviations in isentropic compressibilities, and intermolecular free length were evaluated and interpreted in terms of molecular interactions occurring in the mixtures. The excess molar volumes and deviation in isentropic compressibility of the mixture containing [ZnCl2][acetic acid] with methanol and ethanol were seen to be negative across all compositions and temperatures. Conversely, positive excess molar volumes were observed for the mixture containing [ZnCl2][acetic acid] 1:4 with propanol. The isentropic compressibility values demonstrate a direct relationship with the increase in temperature while maintaining a consistent composition throughout all examined binary mixtures. The intermolecular free length values also demonstrate a positive correlation with increasing temperatures. To deepen our comprehension, we used the Redlich-Kister equation with temperature-dependent parameters to establish a correlation between excess molar volumes and variations in compressibilities. This enabled us to gain valuable knowledge on the thermodynamic characteristics and mixing properties shown by these binary systems. Finally, the density of the mixtures composed of DES and 1-alkanol was correlated with PC-SAFT EoS, and Nomoto's relation was successfully used for the modelling of speed of sound as a predictive approach. This approach enhances the applicability of the findings in practical scenarios. This investigation not only enhances the fundamental comprehension of ZnCl2-based DES and alkanol combinations but also provides practical perspectives on their thermophysical characteristics, which may have implications for their potential implementation in diverse industrial sectors. The work presents novel discoveries and correlations, expanding the knowledge base in this domain. These findings contribute to the broader understanding of DES and alkanol mixtures, offering valuable insights for researchers and practitioners alike.