The utilization of CO2 as a building block, in the synthesis of multi-carbon compounds, which generally have greater volumetric and gravimetric energy density beyond the traditional C1 products (that are typical of CO2 hydrogenation), remains an unsolved challenge. Specifically, propylene glycol methyl ether (PGME; C4H10O2), which is a C4 oxygenated compound, produced annually at a multi-million-ton scale from petroleum-based propylene oxide is of particular interest as it has versatile industrial and commercial applications including its role as a power booster component of diesel fuel, as an anti-freezing additive for jet-fuel, as a bio-degradable solvent in a variety of commercial processes, as well as an intermediate for PGME-acetate (which is a photoresist solvent in the semiconductor industry). In contrast to that petroleum-based derivation of this compound, herein, we present a simple and straightforward system that uses CO2 as the C1 feedstock for the synthesis of PGME by the direct hydrogenation and subsequent C-C coupling at moderate temperatures using a heterogeneous Ru and Ir catalyst without any other sacrificial reagent. We were able to maximize PGME productivity by avoiding unwanted side reactions through the optimization of reaction conditions. Altogether, 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 a C1 feedstock.
Chief Senior Researcher at the National Institute of Advanced Industrial Science and Technology (AIST)