COIMPREGNATED, SEQUENTIAL, AND REVERSE SEQUENTIAL LI/SR/SIO2 CATALYSTS FOR THE OXIDATIVE COUPLING OF METHANE IN THE ABSENCE AND PRESENCE OF TETRACHLOROMETHANE - ACTIVE, SELECTIVE, AND STABLE CATALYSTS

Binary lithium and strontium catalysts supported on silica are prepared by coimpregnation, sequential, and reverse sequential methods and are compared in the oxidative coupling of methane to ethane and ethylene for various loadings of strontium and lithium and in the absence and presence of tetrachloromethane (TCM) in the feedstream. The 10% Li/10% Sr/SiO2 catalyst produces C-2+ yields up to 29% and is stable for times on-stream up to at least 600 h. The high yield and stability are attributed to the formation of strontium and lithium silicates which are resistant to high temperatures and destructive gaseous environments.