Continuous gas-phase oxidation of methane into methanol over Cu-mordenite.

The direct conversion of methane into methanol is an ideal, highly promising process; however, its application remains challenging. Herein, a systematic study was carried out on the continuous gas-phase oxidation of methane into methanol with steam in the absence and presence of O 2 over Cu-mordenites (Cu-MOR) with various Cu loadings. The methanol productivity depended on the Cu/Al ratio of the Cu-MOR; it could be maximized by selecting the optimum Cu/Al ratio. Methanol productivity increased as the concentration of O 2 in the feed increased from 0 to 100 ppm. However, methanol selectivity decreased when the O 2 concentration in the feed was above 25 ppm. The stable methanol production rates based on the Cu content were 0.14 and 0.70 mol CH 3 OH/mol Cu/h at 400 °C over a Cu-MOR catalyst with 6.2 wt% Cu under anaerobic conditions and one with 3.0 wt% Cu in the presence of 25 ppm O 2 , respectively. [Display omitted] • Continuous gas-phase oxidation of methane into methanol was examined over Cu-mordenites (Cu-MOR). • The methanol productivity depends on the Cu/Al ratio of the Cu-MOR. • The methanol productivity increases with increasing O 2 concentration in the feed from 0 to 100 ppm. • The methanol selectivity decreases with increasing O 2 concentration above 25 ppm. [ABSTRACT FROM AUTHOR]