Methane oxidative coupling over titanate catalysts

Abstract

The oxidative coupling of methane was studied by cofeeding methane and oxygen over a series of titanate catalysts. Many of the titanate catalysts were good combustion catalysts and had poor hydrocarbon selectivities. Calcination and reduction pretreatments were shown to affect the activity of some catalysts: while they had little influence on other titanate catalysts. The lanthanum titanate catalyst had the best hydrocarbon selectivities of the titanates studied, exhibiting methane conversions of 20% and hydrocarbon selectivities of better than 50% for a variety of operating conditions. The effect of operating conditions were studied, and there appears to be an optimum to achieve high yields of ethane and ethylene. The catalyst was studied over a seventy-two hour period and showed very little change with time-on-stream. The lanthanum titanate catalyst activated methane at much lower temperatures than other catalysts; however, its hydrocarbon selectivity was poorer at lower temperatures.