No matter of course: Ionic liquids as SO2-selective gas absorbers

Carmen Froschauer, Hedda K. Weber, Thomas Röder, H. Sixta, Gerhard Laus, Bernhard Lendl, Herwig Schottenberger

    Research output: Contribution to journalArticleScientific


    Under the perspective of potential technical off-gas recovery and recycling, a series of ionic liquids (ILs)
    was compared and screened for their applicability as environmentally benign solvents for absorbing sulfur
    dioxide (SO2). New molten salts based on imidazolium cations, combined with the 2-formylbenzenesulfonate
    anion were developed and identified as unique, regenerative scrubbing agents for SO2. In particular,
    the room temperature ILs 1-butyl-3-methylimidazolium 2-formylbenzenesulfonate (BMIM OFBS) and
    1-allyl-3-methylimidazolium 2-formylbenzenesulfonate (AMIM OFBS) were compared to already known
    SO2-absorbing systems. In their entirety of required properties for absorb-ing and desorbing SO2, the newly
    introduced systems are superior to all IL-based scrubbing media described so far: These innovative taskspecific
    ILs exhibit low hygroscopicity, good recyclability and, most notably, a remarkable selectivity between
    the sour gases SO2 and CO2, even in the state of ambient moisture saturation. As such, the compounds are
    providing a high application potential for pressure or temperature swing absorption cycles. The presented
    primary results substantiate the advantage of the sheer number of compositional possibilities in developing
    ionic liquids for special purposes.
    Original languageEnglish
    Pages (from-to)30-43
    JournalLenzinger Berichte
    Issue number91
    Publication statusPublished - 2013
    MoE publication typeB1 Article in a scientific magazine


    • process gas desulfurization
    • waste prevention
    • gas absorption
    • selective absorption
    • sustainable chemistry


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