Synthesis of methyl mercaptan from carbonyl sulfide over sulfide K ₂MoO₄/SiO₂

The synthesis of methyl mercaptan from COS and H₂ on K ⁺ promoted MoS₂ supported on silica is explored. The reaction proceeds via the disproportionation of COS to CO₂ and CS₂ and the consecutive hydrogenation of CS₂ to CH ₃SH. In parallel to the disproportionation, COS also decomposes to CO and H₂S. The characterization of the catalyst by means of XRD, Raman spectroscopy, and adsorption of NO suggests that two active phases, i.e., relatively pure MoS₂ and K⁺-decorated MoS₂, are present in the sulfided catalyst. The disproportionation of COS and the hydrogenation of CS₂ are favored on K⁺-decorated MoS ₂; the decomposition of COS to CO is the favored route on pure MoS₂. The reaction mechanisms for the decomposition of COS and the hydrogenation of CS₂ are discussed.