Deep eutectic solvents with multiple weak acid sites for highly efficient, reversible and selective absorption of ammonia

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Developing new and facile strategies for multiple-site reversible chemical absorption of pollutant gases is of wide interests in chemical engineering research. Herein, a series of lithium (Li)-triethylene glycol (TEG)-chelated ionic liquids (ILs) with crownether-like cation and different anions were designed. The Li-TEG-chelated ILs were prepared in quantitative yields by simply mixing equimolar TEG and Li salts. It is found that the chelation of TEG with Li + activates the hydroxyl sites in TEG for strong interaction with ammonia (NH 3 ). Thus, the hydroxyl sites chelated with Li + , as well as the chelation-unsaturated Li + , provide the multiple sites for chemical absorption of NH 3 in Li-TEG-chelated ILs. Moreover, the absorption of NH 3 in Li-TEGchelated ILs is totally reversible, with the NH 3 solubilities remaining unchanged after eight times of recycling. The results obtained herein can provide useful guidance for the construction of gas absorbents with high capacity and excellent reversibility.

Section: Resultssupporting

confidence: 77%

Section: Methodsmentioning

confidence: 99%

Section: Measurements Of Nh 3 Solubilitiesmentioning

confidence: 99%

“…This is a phenomenon commonly observed for the densities and viscosities of gas absorbents. [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] The density of Li-…”

Section: Characterizations Of Li-teg-chelated Ilsmentioning

confidence: 99%

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Chelation‐activated multiple‐site reversible chemical absorption of ammonia in ionic liquids

Cai

Zhang

et al. 2022

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“…Therefore, the effect of water on NH 3 solubilities in metal‐based DESs prepared in this work is very minor. Table 2 presents the comparison of NH 3 solubilities in different DESs and ILs 25,36–50,65–76 . It is found that the solubilities of NH 3 in metal‐based DESs prepared in this work are remarkably high, especially at low pressures.…”

Section: Resultsmentioning

confidence: 83%

Remarkable NH₃ absorption in metal‐based deep eutectic solvents by multiple coordination and hydrogen‐bond interaction

Cheng

Lan

et al. 2022

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The elimination and recycling of NH3 from the vented circulating stream of NH3 synthesis process is of great significance to the protection of air environment and saving of NH3 product. Deep eutectic solvents (DESs) with as many weak acidic sites as possible are anticipated to exhibit high efficiency for NH3 absorption at low pressures. Herein, we designed and prepared a series of metal‐based DESs by mixing EaCl, metal chloride (SnCl2, ZnCl2, FeCl3, or CoCl2), and Gly. The physiochemical properties, NH3 absorption performance, and mechanism of prepared metal‐based DESs were investigated systematically. It is found that considerably high solubilities of NH3 in DESs can be achieved by utilizing the multiple coordination and hydrogen‐bond interaction with NH3 provided by metal ions and Gly respectively. The values of NH3 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.

Evaluating diethanolammonium chloride as liquid solvent for gas separation from experiments and theoretical calculations

Zhang,

Fang,

Zheng

et al. 2023

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This study explored diethanolammonium chloride ([DEA]Cl) as a potential ionic liquid from low‐cost and commercial ones for gas separation. There are three kinds of functional sites in [DEA]Cl: acidic NH2+, hydrogen‐bond OH, and nucleophilic Cl−. The separation of NH3/N2/H2, SO2/CO2/N2, and H2S/CO2/CH4 was considered, because the three mixtures are extensively involved in many industrial processes. The experimental results demonstrated that [DEA]Cl exhibited excellent ability to separate the mixture of NH3/N2/H2. The [DEA]Cl also exhibited the proper capacity to separate SO2/CO2/N2, but the capacity of [DEA]Cl for the separation of H2S/CO2/CH4 was inferior. The theoretical calculations revealed that NH2+ and OH worked synergistically to contribute to the ability of [DEA]Cl for excellent separation of NH3 from NH3/N2/H2, with Cl− contributing to the proper separation of SO2 from SO2/CO2/N2. This study provides experimental and theoretical basis for the industrial application of [DEA]Cl in the area of gas separation.