Nonideal Behavior of Aqueous Deep Eutectic Solvents Based on Tetrabutylphosphonium Bromide and Ethylene Glycol/Glycerol

Understanding the effect of solvents on the thermophysical properties of deep eutectic solvents (DESs) is crucial to utilize their green credentials in several industrial processes. Herein, we explore the nonideal behavior of aqueous DES mixtures to better understand the prevailing intermolecular interactions within them. The used DESs are composed of tetrabutylphosphonium bromide and ethylene glycol/glycerol. The nonideal behavior is explored through calculating the excess molar volume (VmE) and viscosity deviation (ln ηm) over the entire range of compositions and the temperature range from 293.15 to 323.15 K at 101.3 kPa pressure. The values of VmE and ln ηm are fitted with the Redlich–Kister-type polynomial equation. The negative VmE and ln ηm values indicate the strong H-bonding interactions between the DES and water and destruction of the DES structure. The experimentally calculated values of VmE are further evaluated using the well-known Prigogine–Flory–Patterson (PFP) theory and extended real association (ERAS) model. Looking at their increasing utilization, we believe that the results of the present study will be beneficial for designing various industrial equipment and processes

Molecular interaction study through experimental and theoretical volumetric, transport and refractive properties of <i>N</i>-ethylaniline with aryl and alkyl ethers at several temperatures

<div><p>ABSTRACT</p><p>To investigate the molecular interaction study between secondary amine with aryl and alkyl ether, we report densities, speeds of sound, viscosities and refractive indices of <i>N</i>-ethylaniline (NEA) with aryl (anisole, phenetole) and alkyl (tert-butyl methyl ether) ether over the entire composition regime and in the temperature range of 293.15–323.15 K at 5 K intervals. Various excess and transport properties were derived from the experimental data and the excess parameters were fitted to the Redlich–Kister polynomial equation using multiparametric non-linear regression analysis to derive the binary coefficients and to estimate the standard deviation. Molecular interactions between the unlike molecules were analysed through dipole–dipole interactions, cross-association between the components of the mixtures and H-bond formation. Viscosity and refractive index of the mixtures were predicted through several empirical equations and compared with the experimental results. Prigogine–Flory–Patterson statistical theory was used to predict the excess molar volume results.</p></div