Efficient Absorption of SO₂ by Deep Eutectic Solvents Formed by Biobased Aprotic Organic Compound Succinonitrile and 1-Ethyl-3-methylimidazolium Chloride

Abstract

We report that deep eutectic solvents can be formed by biobased aprotic organic compound succinonitrile (SN) functionalized as the hydrogen bond donor with solid ionic liquid 1-ethyl-3-methylimidazolium chloride ([Emim]­[Cl]) or 1-ethyl-3-methylimidazolium hexafluorophosphate ([Emim]­[PF6]). The results suggested the formation of intermolecular hydrogen bonds between the anions of imidazolium salts and the C–H hydrogen of SN. Moreover, the deep eutectic solvent [Emim]­[Cl]-SN(1:1) exhibited an attractive SO2 absorption capacity (0.120 g SO2/g solvent) at low SO2 partial pressure (2000 ppm), which was more than two times the amount captured by [Emim]­[Cl]-ethylene glycol (EG)(1:1) (0.047 g SO2/g solvent) at the same conditions, although the concentration of [Emim]­[Cl] in [Emim]­[Cl]-SN(1:1) (64.7 wt %) was lower than that in [Emim]­[Cl]-EG(1:1) (70.3 wt %). The high SO2 absorption capacity of [Emim]­[Cl]-SN(1:1) was mainly because of the strong charge-transfer interaction between S of SO2 and Cl–, which was investigated by using Fourier transform infrared spectroscopy and theoretical calculations.

Manufacturing Acidities of Hydrogen-Bond Donors in Deep Eutectic Solvents for Effective and Reversible NH3 Capture

“…Moreover, the physiochemical properties of ILs and DESs can be easily tuned by manufacturing the structures and/or compositions of ILs and DESs. Therefore, ILs and DESs are regarded as the next-generation solvents for gas separation, , and there have been enormous studies dedicated to the development of ILs- and DESs-based solvents for green and efficient capture of CO 2 , − SO 2 , − and H 2 S. − …”

Capture of Acidic Gases from Flue Gas by Deep Eutectic Solvents

“…It is reported that imidazolium-based ILs exhibited considerable SO 2 absorption capacity. Therefore, Yang et al [41][42][43] designed a series of EmimCl-based DESs, including EmimCl:EG DES (1:1), EmimCl:triethylene glycol(TEG) DES (1:1), and EmimCl:succinonitrile (SN) DES (1:1), for efficient SO 2 capture and obtained the corresponding absorption capacity of 1.03, 0.91, and 1.13 g SO 2 /g DES, respectively, at 293.15 K and 101 kPa. It showed that the efficiency of imidazolium cation is better than that of ammonium.…”

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

“…Yang et al [ 106 ] investigated the effect of HBD of DESs [EMIMC/EG (1:1), EMIMC:TEG (1:1), and EMIMC:SNT (1:1)] on the solubility of SO 2 . The effect of HBD was ordered as SNT > EG > TEG for SO 2 capture.…”

“…SO 2 capture via DESs decreased linearly with increasing temperature. Yang et al also reported that the absorption capacity of SO 2 using EMIMC/EG, EMIMC/TEG, and EMIMC/SNT decreased with increasing temperature [ 104 , 105 , 106 ].…”