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

Abstract

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.