Screening of ionic liquids to capture CO2 by COSMO-RS and experiments

✍ Scribed by Xiaochun Zhang; Zhiping Liu; Wenchuan Wang

• Publisher: American Institute of Chemical Engineers
• Year: 2008
• Tongue: English
• Weight: 199 KB
• Volume: 54
• Category: Article
• ISSN: 0001-1541
• DOI: 10.1002/aic.11573

✦ Synopsis

Abstract

A screening method is proposed for the molecular design of ionic liquids (ILs) to capture carbon dioxide (CO~2~), which can reduce efficiently the necessary experimental efforts. The COSMO‐RS method is implemented to predict the Henry's law constants of CO~2~ in 408 ILs with various combinations of cations and anions. It is found by the screening that the ILs with the anion tris(pentafluoroethyl)trifluorophosphate ([FEP]) show improved capability to capture CO~2~, compared with other ILs reported in literature. Then, three [FEP]‐based ILs are chosen to perform the solubility measurements by the intelligent gravimetric analyzer (IGA 003, Hiden Analytical), with cations of 1‐hexyl‐3‐methylimidazolium ([hmim]), 1‐butyl‐1‐methylpyrrolidinium ([bmpyrr]), and S‐ethyl‐N,N,N′,N′‐tetramethylthiouronium ([ETT]) at 283.2, 298.2, and 323.2 K, up to the pressure of 1.8 MPa. The experimental data show that the solubility of CO~2~ in [hmim][FEP] is about 15% higher than that in 1‐hexyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide ([hmim][Tf~2~N]), which is in fair agreement with the screening results, indicating the method proposed in this work is reliable. © 2008 American Institute of Chemical Engineers AIChE J, 2008