The efficient conversion of H2S into mercaptan alcohols mediated in protic ionic liquids under mild conditions

Abstract

The resource utilization of hydrogen sulfide (H₂S) is an important and promising topic in energy chemical engineering. Previous products developed in our group through H₂S conversion are sulfur or mercaptan acids. An alternative way to convert H₂S is still desirable. Herein, we have developed a green and mild method to convert H₂S into mercaptan alcohols by the addition reaction with epoxide mediated in tertiary amine-functionalized protic ionic liquids (PILs). Reaction kinetics, substrate scope, and regeneration experiments have all been explored. Almost quantitative conversion of substrates was realized with a catalytic loading of PILs at 30 °C. Water extraction was used to recycle the catalysts from the reaction system. It is believed that the excellent results, together with its operational simplicity and the ability to successively reuse the catalyst, make this new methodology environmentally benign and cost-effective. The generality of the H₂S resource methodology gives it potential for application on an industrial scale.