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

The aim of the study is to determine the effect of process parameters on dielectric propertiesof deep eutectic solvents (DESs), which have beenwidely used in recent years. In this study, DESs wereprepared using choline-chloride as the hydrogenbondacceptor and glycerol, formic acid and aceticacid as the hydrogen-bond donor. The effect of differentprocess parameters such as molar ratio (1:2, 1:3and 1:4), water content (15%, 30% and 45%), temperature(25, 50 and 75 °C) and frequency on dielectricproperties of the DESs were examined. The highestdielectric constant values were found to be38.13±0.54, 44.96±0.07 and 46.74±0.02 for glycerol,formic acid and acetic acid, respectively for the processconditions of 25 °C temperature, 45% water contentand 1:4 molar ratio (at 2450 MHz). Moreover, forall DESs, it was found that a decrease in water contentresulted in a decrease in both dielectric constant andloss factor values. This can be explained by the absenceof free water molecules which are responsiblefrom dipole rotation mechanism. In light of the results,if DES will be used in microwave processes, formicor acetic acid containing DESs might give moresuccessful results compared to the ones with glycerol