Synthesis of methyl mercaptan from carbonyl sulfide over sulfide K2MoO4/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 CH3SH. 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 MoS2; 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.

The synthesis of CH3SH on K+ promoted MoS2/SiO2 from COS and H2 proceeds through the disproportionation of COS and the consecutive hydrogenation of CS2 mainly on the K+-MoS2 phase. In parallel, COS is reduced to CO and H2S on the unpromoted MoS2 phase.Figure optionsDownload high-quality image (50 K)Download as PowerPoint slideHighlights
► COS is used as educt for the synthesis of CH3SH which has received limited attention.
► COS decomposes to CO and H2S and disproportionates to CO2 and CS2, whereas CS2 hydrogenates to CH3SH.
► Two active phases are present MoS2 catalyzes COS decomposition and K+-MoS2 promotes the COS disproportionation.
► Reaction mechanisms for COS decomposition and CS2 hydrogenation are given.