Thermophysical properties of novel ammonium‐based eutectic solvents with ethane‐1,2‐diol and ZnCl₂

Abstract

Background Deep eutectic solvents (DESs) are new types of tunable solvents that have attracted a large scientific community due to their versatile applications and attractive physical properties. Ammonium‐based solvents are widely used in desulfurization processes, but they are toxic and expensive. Thus, to replace the conventional ammonium‐based solvents, this work aims to synthesize novel ammonium–ethylene glycol (EG)‐based ternary DESs (TDESs). The thermophysical properties, such as viscosity, density, acidity, stability, degradation point, melting point, conductivity, refractivity and miscibility, were measured in this study. Results The TDESs were prepared using varying molar ratios ranging from 1:3 to 1:5 by combining a hydrogen bond donor (EG) with ZnCl2 and three ammonium‐based hydrogen bond acceptors, namely ethylammonium chloride, diethylammonium chloride and diethylethanolammonium chloride. It was found that most properties are significantly superior to those of the constituent components of the TDESs. Arrhenius and linear equation fittings with respect to temperatures ranging from 20 to 100 °C predict R2 values close to unity. The viscosity, pH and density decrease while electrical conductivity increases with increasing temperature. Conclusion Such interesting observations are mainly caused by the particles’ excitation phenomena that increase their kinetic energy and volume. Furthermore, the lower melting point of TDESs compared to the constituent components is attributed to the charge delocalization through hydrogen bonding between donor and acceptor molecules. © 2022 Society of Chemical Industry (SCI).

Application of PC‐SAFT EoS and SCFT for the modeling of thermophysical properties comprising deep eutectic solvent and alcohols

“…Thermal expansivities, α, were calculated from the density and V E results, to allow better understanding of change in the solution structure during blending. Thermal expansion coefficients for pure components and compositions for the binary mixture, respectively are expressed from Equations ( 13) and (14), respectively,…”

“…12,13 Furthermore, preliminary reports suggest that ZnCl (II)based DESs have a wide range of potential applications due to their unique properties, such as low toxicity, biodegradability, low cost, and high stability. 14,15 Here are some examples of the potential applications of ZnCl (II)based DES. Cellulose processing: ZnCl (II)-based DESs can dissolve cellulose and other polysaccharides, making them potentially useful in the production of biofuels, pharmaceuticals, and other products derived from biomass.…”

Density and viscosity of deep eutectic solvents at different temperatures and compositions: Measurement and prediction model

“…To assess the general T A B L E 1 3 Density literature values of ChCl:EG = 1:3, 1:4, 1:5 and EAC:Gly:ZnCl 2 = 1:3:0.25, 1:4:0.25, 1:5:0.25. 46,47 ChCl:EG ρ/g cm À3 EAc:Gly:ZnCl 2 ρ/g cm À3 T 1:3 applicability of the model, we also applied it to fit density experimental data from other literature sources. 46,47 The experimental data from the literature can be found in Table 13, while the corresponding fitting parameters with the model are presented in Table 14.…”

“…46,47 ChCl:EG ρ/g cm À3 EAc:Gly:ZnCl 2 ρ/g cm À3 T 1:3 applicability of the model, we also applied it to fit density experimental data from other literature sources. 46,47 The experimental data from the literature can be found in Table 13, while the corresponding fitting parameters with the model are presented in Table 14. In order to better validate the universality of the model, we have included density data for low eutectic solvent systems from other literature sources, and the corresponding fitting results and predictive performance are shown in Tables S2 and S3 and Figure S1.…”

“…The corresponding fitting parameters can be found in Tables 16 and 18, respectively. To confirm its applicability, the model is also employed to fit the experimental viscosity data 46,47 from other publications. The viscosity data from these sources are presented in Table 17.…”