REACTION OF METHANE AND SULFUR - OXIDATIVE COUPLING AND CARBON-DISULFIDE FORMATION

Reaction between methane and sulfur vapor (mainly S2) has been studied at 773-1073 K in the presence of possible catalysts and in the absenc e of a catalyst. Reaction was carried out in a silica tube reactor at a total pressure of 1 atm with excess methane, with prereaction sulfid ation using H2S/H-2. Sm2O3 had significant catalytic effect on CH4 con version, but all other potential catalysts (including Li/MgO) gave CH4 conversion close to that in the absence of catalyst. CS2 was the majo r product, accompanied by C2 coupling product which in most cases was predominantly C2H4 with some C2H6. In some cases, small amounts of C3, C4 hydrocarbons and CH3SH, (CH3)2S, (CH3)2S2 were also found. Experim ents with varying space velocity indicated that C2H6 was the primary c oupling product. Possible reaction pathways are discussed in terms of homogeneous CH 3-generation, augmented by CH3. generated heterogeneous ly at the surface of sulfided Sm2O3. Sulfidation of Li/MgO is consider ed to be the reason for the inactivity of this potential catalyst.