Densities and viscosities of, and NH3 solubilities in deep eutectic solvents composed of ethylamine hydrochloride and acetamide

Abstract

Deep eutectic solvents (DESs) are a novel class of green solvents with promising application in gas separation. The physical properties of, and gas solubilities in DESs are fundamental data for industrial process design. In this work, the densities and viscosities of ethylamine hydrochloride (EaCl) plus acetamide (AA) mixtures were determined in the temperature range of (313.2–353.2) K. The density data and viscosity data were fitted to a linear equation and the Vogel-Fulcher-Tammann equation respectively. Furthermore, the solubilities of NH3 in EaCl + AA mixtures were determined in the temperature range of (313.2–353.2) K and pressure range of (0–300.0) kPa. It is found that the isothermal profiles for NH3 absorption slightly deviate from ideal type, probably due to the strong hydrogen-bond interaction between NH3 and EaCl. The solubilities of NH3 in EaCl + AA mixtures are fairly good, with the value of 3.84 mol·kg−1 at 313.2 K and 96.4 kPa for EaCl + AA (1:1). The solubility data were fitted to the Krichevsky-Kasarnovsky equation to calculate the Henry’s constants of NH3 in EaCl + AA mixtures. With the Henry’s constants at different temperatures, the thermodynamic functions such as enthalpy changes, Gibbs free energy changes and entropy changes for NH3 absorption in EaCl + AA mixtures were also estimated.