Remarkable NH 3 absorption in metal‐based deep eutectic solvents by multiple coordination and hydrogen‐bond interaction

The elimination and recycling of NH 3 from the vented circulating stream of NH 3 synthesis process is of great significance to the protection of air environment and saving of NH 3 product. Deep eutectic solvents (DESs) with as many weak acidic sites as possible are anticipated to exhibit high efficiency for NH 3 absorption at low pressures. Herein, we designed and prepared a series of metal‐based DESs by mixing EaCl, metal chloride (SnCl 2 , ZnCl 2 , FeCl 3 , or CoCl 2 ), and Gly. The physiochemical properties, NH 3 absorption performance, and mechanism of prepared metal‐based DESs were investigated systematically. It is found that considerably high solubilities of NH 3 in DESs can be achieved by utilizing the multiple coordination and hydrogen‐bond interaction with NH 3 provided by metal ions and Gly respectively. The values of NH 3 solubilities (17.55 mol/kg at 298.2 K and 103.0 kPa, and 10.24 mol/kg at 298.2 K and 6.8 kPa) are the highest reported to date.