Molar heat capacities and electrical conductivities of two ammonium-based deep eutectic solvents and their aqueous solutions

• DES is made from N,N-diethylethanol ammonium chloride-glycerol or ethylene glycol.
• Heat capacities and electrical conductivities of two DESs and their aqueous solutions were measured.
• The temperature studied was 303.15–353.15 K for heat capacities and 298.15–343.15 K for electrical conductivities.
• The measured data were reported as functions of temperature and composition.
• The measured data were represented satisfactorily by the applied correlations.

In this work, we reported new experimental data on the molar heat capacity, CP, and electrical conductivity, κ, of two ammonium-based deep eutectic solvents (DESs), N,N-diethylethanolammonium chloride-glycerol and N,N-diethylethanolammonium chloride-ethylene glycol, and their aqueous solutions. Heat capacity measurements were performed, using a heat flow differential scanning calorimeter, at atmospheric pressure at temperatures from 303.15 to 353.15 K. The CP values were found to increase with temperature. Excess molar heat capacities, CPE, of the aqueous DES solutions were determined, and represented as function of temperature and DES mole fraction using a Redlich–Kister-type equation. Electrical conductivities were measured from 298.15 to 343.15 K, and a modified form of the Arrhenius equation was used to correlate the obtained κ data with temperature and DES mole fraction. The applied correlations successfully represented the experimental CP and κ data as function of temperature and composition at low average absolute deviations of 0.1 and 1.3%, respectively.