Designing Low-Viscosity Deep Eutectic Solvents with Multiple Weak-Acidic Groups for Ammonia Separation

Abstract

Developing NH 3 separation technology with high efficiency is very meaningful for the advancement of the NH 3 synthesis process. In this work, a new class of deep eutectic solvents (DESs) were designed by pairing N,N,N′,N′-tetramethyl-1,3-propanediamine dihydrochloride ([TMPDA]Cl 2 ) with phenol (PhOH) at the molar ratios of 1:3∼7. [TMPDA]Cl 2 + PhOH DESs have multiple weak-acidic groups and viscosities of as low as 48.1 cP at 298.2 K. They also exhibit excellent performance for the separation of NH 3 , showing not only efficient and selective but also reversible absorption of NH 3 . Especially, the solubilities of NH 3 in [TMPDA]Cl 2 + PhOH DESs at low pressures can reach 4.49 mol/kg of NH 3 at 298.2 K and 13.3 kPa, being superior to those of most of the DESs and ILs reported in the literature. The mechanism of NH 3 absorption was further elucidated by quantum chemistry calculations and 1 H NMR spectra. It is validated that the efficient absorption of NH 3 in DESs origins from the strong interaction of multiple weak-acidic groups of DESs with NH 3 .

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

“…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.…”

Cuprous‐based composite ionic liquids for the selective absorption of CO: Experimental study and thermodynamic analysis

“…The densities and viscosities data of liquid absorbent are fundamental physical properties for the devise of gas absorption process. [22][23][24] As shown in Figure 1 1) and (2), 25,26 respectively.…”

“…The densities and viscosities data of liquid absorbent are fundamental physical properties for the devise of gas absorption process 22–24 . As shown in Figure 1, the densities and viscosities values of three cuprous‐based composites ILs at 293.15–353.15 K. The sequence of density was as follows: [EimH][OAc]–0.7CuOAc > [EimH][OAc]–0.6CuOAc > [EimH][OAc]–0.5CuOAc.…”

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

“…Ionic liquids (ILs) have shown promising application in gas separation given the wide liquid range, extremely low volatility and unlimited motif choices of them 19–27 . Within this regard, it is necessary to obtain ILs with high capacity and excellent reversibility for gas absorption.…”

“…Ionic liquids (ILs) have shown promising application in gas separation given the wide liquid range, extremely low volatility and unlimited motif choices of them. [19][20][21][22][23][24][25][26][27] Within this regard, it is necessary to obtain ILs with high capacity and excellent reversibility for gas absorption. To achieve this goal, introducing multiple-site reversible chemical absorption is an effective strategy.…”