Sugar Choline-Chloride-Based Natural Deep Eutectic Solvents: Effects of Water Content
Natural deep eutectic solvents (NADES) are green solvents with a melting point far below both constituent pure molecules due to hydrogen bonding. These solvents have the potential to be applied to the industrial processing of food products, cosmetics, pharmaceuticals, and other extraction processes. In the present study, the characteristics of natural deep eutectic solvents composed of hydrogen bond acceptor choline chloride (ChCl: 2-hydroxyethyl-trimethylammonium chloride), and a hydrogen bond donor saccharide are cataloged. The specific saccharides studied include disaccharides sucrose and lactose, and the monosaccharides glucose and fructose. Four NADES were prepared with varying molar ratios of 1:1, 2:1, and 4:1 ChCl: saccharide solid mixtures, heated at 80°C and mixed under magnetic stirring at 500 RPM from 2 hours to 48 hours depending on the solvent. This work also analyzed the effects of water content on the selected ChCl: saccharides NADES preparation and physical properties. It has been shown that the addition of water decreases hydrogen bonding interactions, reduces viscosity, and increases conductivity. In this work, the four as-prepared ChCl: saccharides were evaluated at varying mass percentages of water, 0, 10, 20, and 30 wt.%. Physical properties were analyzed, including pH, which tended to be neutral, conductivity, and refractive index, which was about 1.5 nD for the ChCl: saccharide NADES prepared at different conditions. The as-prepared NADES conductivity and surface tension were also measured at room temperature, about 20°C. These results showed a dependence on the saccharide type and water content. The stability and flowability of the NADES were analyzed over time through visual inspection, and the rheology will be studied. From the different saccharides studied, this study concludes the ChCl: Fructose natural deep eutectic solvents showed the most promise for environmental-related applications in terms of stability, and ease of formation, with a relatively acidic pH. On the contrary, ChCl: lactose NADES were challenging to prepare and resulted in non-stable solvents.
Erick Vasquez, Judit Beagle
Primary Advisor's Department
Chemical and Materials Engineering
Stander Symposium, School of Engineering
Institutional Learning Goals
"Sugar Choline-Chloride-Based Natural Deep Eutectic Solvents: Effects of Water Content" (2023). Stander Symposium Projects. 3135.
Presentation: 1:15-2:30 p.m., Kennedy Union Ballroom