Effects of molar ratio, temperature and water content on acidity and viscosity of deep eutectic solvent formed from Choline Chloride-Ethylene Glycerol

Deep eutectic solvents (DESs) become preferred solvents owing to unique features and promising environmentally friendly nature they have. Evaluation their properties is essential in order to use them effectively. Even though DESs are a good alternative to classic solvents, their viscosity is high, limiting their usage in industrial applications. However, this can be overcome by adding cosolvent or varying application conditions. In this study, the effect of temperature ranging from 200C to 600C (293.15- 333.15 K), molar ratio (1:1 to 1:9) and cosolvent addition (water) on acidity and viscosity of DES were investigated. Overall, as a result of this study, operation conditions had a significant effect on acidity and viscosity of DESs. Acidity and viscosity of DESs were on decrease as molar ratio increased, and the increase in temperature negatively affected viscosity of DESs. Dynamic viscosity of DESs were temperature dependence, following Vogel-Fulcher-Tammann (VFT) equality. Cosolvent addition decreased viscosity of DESs. Addition of water higher than 25% did not have a significant effect on viscosity. In addition, water addition decreased acidity of DES up to 1:5 molar ratio, but no significant effect regardless of the amount of water addition on the acidity was determined. These results provide a new perceptive about the mechanism of DES designed for usage in food applications.