Effective absorption of <scp>SO<sub>2</sub></scp> by imidazole‐based protic ionic liquids with multiple active sites: Thermodynamic and mechanical studies
Ping Liu, Kaixing Cai, Xiaomin Zhang, Tianxiang Zhao
Abstract
Abstract In view of the environmental hazards caused by SO 2 , the development of efficient SO 2 capture technology has important practical significance. In this work, a low‐viscosity protic ionic liquids containing imidazole (Im), ether linkage, and tertiary amine structure was synthesized by acid–base neutralization of tris(3,6‐dioxaheptyl)amine (TMEA) and Im for SO 2 absorption. The results showed that the solubility of SO 2 in [TMEA][Im] reached 12.754 mol kg −1 at 298.2 K and 1 bar and the ideal selectivity of SO 2 /CO 2 (1/1) is 141.7 at 1 bar. Furthermore, [TMEA][Im] can be reused and the SO 2 absorption performance was not significantly reduced after five cycles. In addition, the absorption of low‐concentration SO 2 (2000 ppm) in [TMEA][Im] was also tested. Further spectroscopic research and thermodynamic analysis suggested that the high SO 2 uptake by [TMEA][Im] was caused by the synergistic effect of physical and chemical absorption.