EFFECTS OF MOLAR RATIO, FREQUENCY, WATER CONTENT AND TEMPERATURE ON DIELECTRIC PROPERTIES OF DEEP EUTECTIC SOLVENTS

Abstract

In this study, deep eutectic solvents (DESs) were prepared using choline-chloride as the hydrogen-bond acceptor and glycerol, formic acid and acetic acid as the hydrogen-bond donor. The effect of different process parameters such as molar ratio (1:2, 1:3 and 1:4), water content (15%, 30% and 45%), temperature (25, 50 and 75 °C) and frequency on dielectric properties of the DESs were examined. In conclusion, the highest dielectric constant value was detected at 25 °C for all DESs. Moreover, for all DESs, it was found that a decrease in water content resulted in a decrease in both dielectric constant and loss factor values. This can be explained by the absence of free water molecules which are responsible from dipole rotation mechanism. In light of the results, if DES will be used in microwave extraction, formic or acetic acid containing DESs might give more successful results compared to the one with glycerol.