Homogeneous, catalytic, oxidative coupling of methane to acetic acid in one step

Acetic acid is an important petrochemical that is currently produced front methane (or coal in a three-step process based oil carbonylation of methanol. We report a direct, selective, oxidative condensation of two methane molecules to acetic acid at 180 degrees C in concentrated sulfuric acid. C-13 isotopic labeling studies show that both carbons of acetic acid originate front two methane molecules in a formal eight-electron redox reaction. The reaction is catalyzed by palladium and the results are consistent with the reaction occurring by tandem catalysis involving methane C-H activation to generate Pd-CH3, species. followed by efficient oxidative carbonvlation with methanol, generated in sau front methane. to prodnce acetic acid. Control Experiments SUggCSt that the carbonylation occurs Via the in situ oxidation of CH3OH to low levels of CO.