Carbonate-Promoted Hydrogenation of Carbon Dioxide to Multicarbon Carboxylates

[Image: see text] CO(2) hydrogenation is a potential alternative to conventional petrochemical methods for making commodity chemicals and fuels. Research in this area has focused mostly on transition-metal-based catalysts. Here we show that hydrated alkali carbonates promote CO(2) hydrogenation to formate, oxalate, and other C(2+) carboxylates at elevated temperature and pressure in the absence of transition-metal catalysts or solvent. The reactions proceed rapidly, reaching up to 56% yield (with respect to CO(3)(2–)) within minutes. Isotope labeling experiments indicate facile H(2) and C–H deprotonations in the alkali cation-rich reaction media and identify probable intermediates for the C–C bond formations leading to the various C(2+) products. The carboxylate salts are in equilibrium with volatile carboxylic acids under CO(2) hydrogenation conditions, which may enable catalytic carboxylic acid syntheses. Our results provide a foundation for base-promoted and base-catalyzed CO(2) hydrogenation processes that could complement existing approaches.