Selectivity controlled transformation of carbon dioxide into a versatile bi-functional multi-carbon oxygenate using a physically mixed ruthenium–iridium catalyst

Abstract

To mitigate environmental concern and energy issues, the conversion of carbon dioxide (CO₂) to valuable and useful carbon chemicals offers a promising strategy for the development of a carbon neutral economy. The utilization of inert CO₂ as a building block in the synthesis of multi-carbon (>2) oxygenated compounds, specifically propylene glycol methyl ether (PGME; C₄H₁₀O₂), produced annually at a multi-million-ton scale from petroleum-based propylene oxide is of particular interest because of its multifaceted industrial and commercial applications. Herein, we present a simple and straightforward system that uses CO₂ in compressed form as the C1 feedstock for the synthesis of PGME by direct hydrogenation and subsequent C–C coupling without any other sacrificial reagents. In addition, we combine experimental results with DFT calculations to elucidate the synergistic contributions of two catalytic metals (Ru and Ir) to activation of CO₂ for hydrogenation and consequent mediation of the C–C bond formation leading to the generation of PGME. Taken together, our findings suggest that the strategy presented herewith may serve as a starting point for the development of a sustainable chemical synthesis platform for multi-carbon oxygenates by utilizing CO₂ as the starting material.