Physicochemical and thermal characteristics of choline chloride-based deep eutectic solvents

Physicochemical Properties of Choline Chloride/Acetic Acid as a Deep Eutectic Solvent and Its Binary Solutions with DMSO at 298.15 to 353.15 K

Deep eutectic solvents (DESs) are considered to play an important role in green chemistry and other technological fields as an alternative to organic solvents. The present study reports measurements of density (ρ), speed of sound (u), dynamic viscosity (η), and electrical conductivity (κ) and investigates physicochemical properties of choline chloride/acetic acid (ChCl/AcA DES) and its binary mixtures with dimethyl sulfoxide (DMSO) over the entire composition and temperature (298.15-353.15 K) range. The density data are well fitted by a second-degree polynomial equation in T. DES/DMSO mixtures exhibit negative excess molar volume and isentropic compressibility deviation with a minimum in respective curves at x1 ≈ 0.15 (x1 is the mole fraction of DES in the mixture), which became deeper with increasing temperature. The ChCl/AcA DES and DMSO curves for excess partial molar volume cross each other at x1 ≈ 0.15, showing that the packing effect is dominant over specific interactions. A similar behavior is observed for excess molar viscosity, showing the minima at x1 ≈ 0.62, and substantiates volumetric results. The temperature dependence of viscosity and conductivity is well described by the Vogel-Fulcher-Tammann (VFT) equation.

Exploring carbohydrate extraction from biomass using deep eutectic solvents: Factors and mechanisms

Deep eutectic solvents (DESs) are increasingly being recognized as sustainable and promising solvents because of their unique properties: low melting point, low cost, and biocompatibility. Some DESs possess high viscosity, remarkable stability, and minimal toxicity, enhancing their appeal for diverse applications. Notably, they hold promise in biomass pretreatment, a crucial step in biomass conversion, although their potential in algal biomass carbohydrates extraction remains largely unexplored. Understanding the correlation between DESs' properties and their behavior in carbohydrate extraction, alongside cellulose degradation mechanisms, remains a gap. This review provides an overview of the use of DESs in extracting carbohydrates from lignocellulosic and algal biomass, explores the factors that influence the behavior of DESs in carbohydrate extraction, and sheds light on the mechanism of cellulose degradation by DESs. Additionally, the review discusses potential future developments and applications of DESs, particularly extracting carbohydrates from algal biomass.