Selective removal of acetylenes from olefin mixtures through specific physicochemical interactions of ionic liquids with acetylenesElectronic supplementary information (ESI) available: Data of pKaqb of RTILs, solubilities of acetylene and ethylene and the optimized structures showing the interactions of [DMIM][MeHPO3] with propyne and propylene. See DOI: 10.1039/b915989d

Imidazolium-based ionic liquids (ILs) bearing an alkylphosphite anion, were highly efficient for the selective removal of acetylenes in olefins. Comparison of solubility data at 313 K and at atmospheric pressure shows that the solubilities of acetylene and propyne in 1,3-dimethylimidazolium methylphosphite ([DMIM][MeHPO 3 ]) are about 45 and 20 times higher than those of ethylene and propylene, respectively. Computational and 1 H NMR results clearly demonstrate that there are substantial interactions between the acidic hydrogen atom or atoms of acetylenes and the phosphite anion. Imidazolium-based room temperature ionic liquids with a basic alkylphosphite anion were highly efficient for the reversible absorption of acetylenes.