The Affinity of the Sulfate- and Ether-Containing Surface-Active Ionic Liquids to Carbon Dioxide, Hydrogen Fluoride, Hydrogen Sulfide, and Water

TL;DR

This study explores how sulfate- and ether-containing surface-active ionic liquids interact with gases like CO2, H2S, HF, and water, highlighting their potential for gas capture and storage in industrial applications.

Contribution

It provides new insights into the specific molecular groups in ionic liquids that influence their affinity for various small molecules, aiding design of targeted gas capture agents.

Findings

Sulfate, ether groups, and aromatic imidazole rings enhance gas sorption.

Tetrabutylammonium cation and hydrocarbon chains have lesser impact.

Data supports use of these ILs for toxic gas capture in industry.

Abstract

The development of novel task-specific ionic liquids (ILs) represents an essential challenge in modern organic and physical chemistries. Recently we reported surface-active ILs contained the two well-known organic cations (1-butyl-3-methylimidazolium and tetrabutylammonium) and the two surface-active anions (lauryl sulfate, lauryl ether sulfate). In the present work, we investigate the affinity of these ionic compounds to the selected small molecules that exhibit practical implications: water, hydrogen fluoride, hydrogen sulfate, and carbon dioxide. We identified that the sulfate group, the ether groups, and the aromatic imidazole ring make the strongest contributions to the physical sorption of the polar gas molecules. In turn, the tetrabutylammonium cation, the saturated hydrocarbon chain of the anions, and the alkyl chains of 1-butyl-3-methylimidazolium contribute to a significantly smaller extent. The reported data are interesting in the context of using surface-active ILs in the oil industry to capture and store undesirable and toxic gases.