Methyl mercaptan production – catalysts and processes

Abstract

Methyl mercaptan is a useful commercial molecule, with well established applications in agro-industry, petrochemistry, mining and polymer industry. Because the market of this intermediate should grow by 5.5% per year, new production capacities must be developed to produce it. In terms of process, methanol thiolation, operated at moderate temperatures and pressure, with tungsten–alumina catalysts promoted with an alkali metal is the largest segment, with a share of 98%. However, during the past years, considerable attention has been paid to alternative approaches of methyl mercaptan production, in particular, the single-step process, which replaces the methanol with syngas (CO/H₂). The catalytic hydrogenation of carbon disulfide and carbonyl sulfide was also investigated. This contribution is a comprehensive overview of the scientific and practical aspects related to the production of methyl mercaptan by both commercial and emerging methods. For each method, its capability as well as the technical advantages and disadvantages has been highlighted. The role of catalysts used in the reviewed processes is particularly emphasized.