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Cation−Anion−CO 2 Interactions in Imidazolium‐Based Ionic Liquid Sorbents
Author(s) -
Simon Nathalia M.,
Zanatta Marcileia,
Neumann Jessé,
Girard AnneLise,
Marin Graciane,
Stassen Hubert,
Dupont Jairton
Publication year - 2018
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201800751
Subject(s) - ionic liquid , chemistry , sorption , physisorption , carboxylate , ion , inorganic chemistry , alkyl , hexafluorophosphate , organic chemistry , adsorption , catalysis
A series of functionalized N‐alkylimidazolium based ionic liquids (ImILs) were designed, through anion (carboxylates and halogenated) and cation (N‐alkyl side chains) structural modifications, and studied as potential sorbents for CO 2 . The sorption capacities of as prepared bare ImILs could be enhanced from 0.20 to 0.60 molar fraction by variation of cation‐anion‐CO 2 and IL‐CO 2 ‐water interaction. By combining NMR spectroscopy with molecular dynamics simulations, a good description of interactions between ImIL and CO 2 can be obtained. Three types of CO 2 sorption modes have been evidenced depending on the structure of the ImIL ion pair: Physisorption, formation of bicarbonate, and covalent interaction through the nucleophilic addition of CO 2 to the cation or anion. The highest CO 2 sorption capacity was observed with the ImIL containing the 1‐ n ‐butyl‐3‐methylimidazolium cation associated with the carboxylate anions (succinate and malonate). This study provides helpful clues for better understanding the structure‐activity relationship of this class of materials and the ion pair influence on CO 2 capture.