CO2 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 CO2 hydrogenation to formate, oxalate, and other C2+ 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 CO32-) within minutes. Isotope labeling experiments indicate facile H2 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 C2+ products. The carboxylate salts are in equilibrium with volatile carboxylic acids under CO2 hydrogenation conditions, which may enable catalytic carboxylic acid syntheses. Our results provide a foundation for base-promoted and base-catalyzed CO2 hydrogenation processes that could complement existing approaches.

中文翻译：

---

碳酸盐促进的二氧化碳加氢生成多碳羧酸盐。

CO2加氢是制造商品化学品和燃料的常规石化方法的潜在替代品。该领域的研究主要集中在过渡金属基催化剂上。在这里，我们表明，在没有过渡金属催化剂或溶剂的情况下，在升高的温度和压力下，水合的碱金属碳酸盐会促进CO2加氢生成甲酸酯，草酸酯和其他C2 +羧酸酯。反应进行迅速，在数分钟内达到最高56％的收率（相对于CO32-）。同位素标记实验表明，在富含碱金属阳离子的反应介质中，H2和CH容易去质子化，并确定了导致各种C2 +产物形成CC键的中间体。在CO2加氢条件下，羧酸盐与挥发性羧酸保持平衡，可以实现催化羧酸的合成。我们的结果为碱促进和碱催化的CO2加氢工艺提供了基础，该工艺可以补充现有方法。