Influence of the Interaction between Hydrogen Sulfide and Ionic Liquids on Solubility: Experimental and Theoretical Investigation

The soly. of H2S in a series of 1-butyl-3-methylimidazolium ([bmim]+) based ionic liqs. (ILs) with different anions, chloride, tetrafluoroborate ([BF4]-), hexafluorophosphate ([PF6]-), triflate ([TfO]-), and bis(trifluoromethyl)sulfonylimide ([Tf2N]-), and in a series of [Tf2N] ILs with different cations, i.e., N-alkyl-N'-methylimidazolium, 2-methyl-N-methyl-N'-alkyimidazolium, N-alkylpyridinium, N-butyl-N-methylpyrrolidinium, and N-alkyl-N,N-dimethyl-N-(2-hydroxyethyl)ammonium has been detd. using medium-pressure NMR spectroscopy. The obsd. solubilities are significantly higher than those reported for many other gases in ILs, suggesting the occurrence of specific interactions between H2S and the examd. ILs. Quantum chem. calcns. have been used to investigate at a mol. level the interaction between H2S and the [bmim]+-based ILs.