Manganese oxide catalyzed methane partial oxidation in trifluoroacetic acid: Catalysis and kinetic analysis

Direct oxidation of methane to methanol has been studied for decades, and has yet to be commercialized. Three years ago, UOP LLC, a Honeywell Company, started a government co-sponsored project (NIST/ATP Award 70NANB4H3041) for selective liquid phase oxidation of methane to methanol. Recently we have discovered an efficient methane oxidation by manganese oxide. When used as stoichiometric oxidant, quantitative metal oxide-based yield was observed for methane oxidation. The spent catalyst activity can be 100% regenerated with air under basic conditions. A high methane-based yield (36%) with high selectivity (>95%) was achieved when manganese oxide was used in catalytic amount in the presence of air for methane oxidation. Our online GC analysis showed that catalytic methane oxidation occurs with two-stage reaction kinetics with constant reaction rate at the active stage, which can be explained by a low steady-state active catalyst concentration as observed by in situ UV–vis spectrometer.