Rational Design of Azole-Based Deep Eutectic Solvents for Highly Efficient and Reversible Capture of Ammonia

Abstract

In this work, three azole-based ternary deep eutectic solvents (DESs) were designed for highly efficient absorption of NH3 by utilizing the weak acidity of azoles. Specifically, the DESs are composed of choline chloride (ChCl); a model azole compound such as imidazole (ImZ), triazole (TrZ), or tetrazole (TetrZ); and ethylene glycol (EG). The effects of liquid composition, pressure, and temperature on NH3 solubilities in DESs were examined systematically. It is found that ChCl + TetrZ + EG displays obvious chemical behavior for NH3 absorption owing to the relatively stronger acidity of TetrZ, and it exhibits the highest NH3 capacities among the three DESs. The NH3 capacities of ChCl + TetrZ + EG are superior to most absorbents/adsorbents previously reported, especially when compared at low pressures. Recycling experiments demonstrate that the chemical absorption of NH3 in ChCl + TetrZ + EG is reversible, with only partial loss in NH3 capacities during absorption–desorption cycles. Furthermore, theoretical calculations were performed to gain molecular insights into the absorption of NH3 in azole-based DESs.

Dual‐functionalized protic ionic liquids for efficient absorption of NH3 through synergistically physicochemical interaction

“…The primary cause of the dramatic shift in 1 H NMR was the chemical complexing and hydrogen bonding between NH 3 and N3─H in the imidazole ring. Such a strong interaction altered the electronic environment of N3 atoms in the imidazole ring, leading to the evolution of a corresponding peak (N3─H) in 1 H NMR . However, the peak at 3.18 ppm disappeared and shifted downfield to overlap with the weak acidity proton signals.…”

“…In order to evaluate the potential of DPILs for industrial applications of NH 3 absorption, the ILs and deep eutectic solvents (DESs) reported to absorb NH 3 were compared with this work, as shown in Table . The results indicated that the NH 3 solubility in [EtOHim][NTf 2 ] is over 30‐fold greater than that of [Emim][NTf 2 ], and four‐fold greater than that of the functionalized IL [EtOHmim][NTf 2 ], which is superior to any nonmetallic ILs reported so far.…”

Promoted absorption of CO at high temperature by cuprous‐based ternary deep eutectic solvents

“…As well known, ILs are composed primarily of one type of discrete anion and cation. In contrast, deep eutectic solvents (DESs) are eutectic mixtures that contain a variety of anionic and/or cationic species 12 . DESs are usually formed by the complexation of a quaternary ammonium salt with a metal halide salt or hydrogen bond donor (e.g., amide, polyol, carboxylic acid) 13 .…”

Utilization of Deep Eutectic Solvents to Reduce the Release of Hazardous Gases to the Atmosphere: A Critical Review

“…The addition of a third component to the binary DESs can affect the solubility of NH 3 . Zhong et al [ 123 ] prepared a ternary DES by combining ChCl with EG and tetrazole and compared the solubility of NH 3 of ternary DES with ChCl/EG and EG. ChCl/tetrazole/EG (3:7:14) showed greater absorption capacity compared to ChCl/EG (3:14) and EG.…”