Bisazole-Based Deep Eutectic Solvents for Efficient SO₂ Absorption and Conversion without Any Additives

Abstract

Four bisazole-based deep eutectic solvents (DESs) consisting of 1ethyl-3-methylimidazolium chloride and azoles are prepared for the efficient absorption and conversion of SO 2 . These DESs can not only absorb SO 2 up to 1.402 g/g at 20 °C and 1 bar but can also serve as catalysts for the cycloaddition of SO 2 with epoxides. Moderate to good yields of cyclic sulfites are acquired for varied epoxides under mild conditions (60 °C and 1 bar of SO 2 ) without any additives.

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

“…The highest solubilities were obtained using TEAC/LV and TEAB/LV DES at all temperatures (293.2–343.2 K), as shown in Figure 8 a. Long et al [ 90 ] investigated the performance of four bisazole-based DESs in SO 2 capture. The DESs were obtained by mixing EMIMC with imidazole, 1H-1,2,4-triazole, 1,2,3-1H-triazole, or tetrazole in a 2:1 (HBA:HBD) molar ratio.…”

Capture of Toxic Gases by Deep Eutectic Solvents

“…82 Particularly, the yield of cyclic sulfites was positively related to the SO 2 absorption capacity, i.e., EMIMCl:imidazole (2:1) > EMIMCl:1H-1,2,4-triazole (2:1) > EMIMCl:1,2,3−1H-triazole (2:1) > EMIMCl:tetrazole (2:1). 82 NH 3 Capture by DESs. Effect of HBA and HBD.…”

“…In addition to regeneration, SO 2 captured by the DES EMIMCl:acetamide could be efficiently (up to 99%) converted into sulfur by adding H 2 S within 5 min. ,,− Recently, Liu et al found that bisazole-based DESs could efficiently absorb SO 2 and catalyze SO 2 conversion into cyclic sulfites without any other additives or metal-containing components . Particularly, the yield of cyclic sulfites was positively related to the SO 2 absorption capacity, i.e., EMIMCl:imidazole (2:1) > EMIMCl:1H-1,2,4-triazole (2:1) > EMIMCl:1,2,3–1H-triazole (2:1) > EMIMCl:tetrazole (2:1) …”

Easy and Efficient Recovery of EMIMCl from Cellulose Solutions by Addition of Acetic Acid and the Transition from the Original Ionic Liquid to an Eutectic Mixture

“…In fact, aqueous dilutions of hydrated salts at a certain range of dilution have also been recently described as DESs [ 16 ]. Moreover, recent works have described the preparation of mixtures of 1-Ethyl-3-methylimidazolium chloride (EMIMCl, playing the role of HBA) and succinonitrile [ 17 ], several amides [ 18 , 19 ] and glycol-derivatives [ 20 , 21 , 22 ], and different azole [ 23 , 24 , 25 ] and pyridinium [ 26 ] bases, playing the role of HBDs. Most of these DESs, as well as some others based on different imidazolium salts such as 1-butyl-3-methylimidazolium chloride and bromide (BMIMCl and BMIMBr), or 1-hexyl-3-methylimidazolium chloride (HMIMCl [ 17 , 27 ]), were used for gas absorption (mainly SO 2 , but also CO 2 or NH 3 ), and insights about the HB complex structure were obtained by NMR and FTIR spectroscopies as well as by theoretical calculations.…”