Synthesis of Methyl Mercaptan and Dimethyl Sulfide

Vapor phase reaction of hydrogen sulfide with methyl alcohol over gamma-alumina to form methyl mercaptan and dimethyl sulfide was studied at 330, 370, 410, and 450°C; under pressures of 1, 4, and 5 kg/cm2; and in the mole ratios of hydrogen sulfide to methyl alcohol of 1 and 5. When the reaction was conducted above 400°C, formation of a small amount of permanent gases was observed. Below 400°C, however, the product consisted practi-cally of dimethyl ether, methyl mercaptan, dimethyl sulfide, and water. As the contact time was Prolonged, the amount of product dimethyl ether reached its maximum and then raduallv decreased to zero. Methyl mercaptan and dimethyl sulfide seemed to be formed simultaneously on the catalyst surface. The apparent activation energies were 10 kcal/mol as calculated based on the reaction rate of methyl alcohol, and 25 kcal/mol as cal-culated based on the rate of formation of methyl mercaptan and dimethyl sulfide.