Synthesis of ethanol via methanol homologation with CO2 and H2 using an industrially relevant Ru–Co catalyst

Homogeneously catalyzed ethanol synthesis from CO2 and H2 usually uses expensive, unstable and complex catalyst precursors, hindering their industrial viability. In this work, a homogeneous catalytic system consisting of economic and stable catalyst precursors (RuCl3·3H2O and CoCl2·6H2O), cocatalyst (LiI) and N-ethyl-2-pyrrolidone (NEP) solvent was designed to accelerate ethanol production via methanol homologation with CO2 and H2. After activation of the catalyst precursors at 200 °C with CO, the target reaction could proceed efficiently under mild conditions (170 °C), with top level reaction selectivity (64.9%) and much higher space time yield (STY) of ethanol (3.9 g L−1 h−1) compared to previous reports with Ru/Co catalysts. The impact of activation conditions, reaction conditions, and the catalytic mechanism of the reaction were studied by a series of control experiments. This method of ethanol production has the advantages of a stable and easily available catalyst, excellent performance, and easy separation and recycling of the catalyst, showing great potential for industrialization.