The ionic liquid-mediated Claus reaction: a highly efficient capture and conversion of hydrogen sulfide

Ionic liquids (ILs) were demonstrated to be highly efficient media for the liquid-phase Claus reaction. The reaction of H2S with SO2 in ILs proceeds very fast and almost completely to result in solid sulfur (S8) under mild conditions without the addition of any catalysts. Various ILs with different cations and anions were investigated and a simple IL 1-hexyl-3-methylimidazolium chloride ([hmim][Cl]) was found to be the most effective for the capture and conversion of H2S. It enables the transformation of H2S to S8 with a conversion ratio as high as >96% within 3 min. This finding opens up a promising method for the capture and conversion of H2S from gas streams.