Methane Carboxylation Using Electrochemically Activated Carbon Dioxide.

Direct synthesis of CH 3 COOH from CH 4 and CO 2 is an appealing approach for the utilization of two potent greenhouse gases that are notoriously difficult to activate. In this Communication, we report an integrated route to enable this reaction. Recognizing the thermodynamic stability of CO 2 , our strategy sought to first activate CO 2 to produce CO (through electrochemical CO 2 reduction) and O 2 (through water oxidation), followed by oxidative CH 4 carbonylation catalyzed by Rh single atom catalysts supported on zeolite. The net result was CH 4 carboxylation with 100 % atom economy. CH 3 COOH was obtained at a high selectivity (>80 %) and good yield (ca. 3.2 mmol g -1 cat in 3 h). Isotope labelling experiments confirmed that CH 3 COOH is produced through the coupling of CH 4 and CO 2 . This work represents the first successful integration of CO/O 2 production with oxidative carbonylation reaction. The result is expected to inspire more carboxylation reactions utilizing preactivated CO 2 that take advantage of both products from the reduction and oxidation processes, thus achieving high atom efficiency in the synthesis.