Low-Temperature Direct Oxidation of Propane to Propylene Oxide Using Supported Subnanometer Cu Clusters

Propylene oxide, a key commodity of the chemical industry for a wide range of consumer products, is synthesized through sequential propane dehydrogenation and epoxidation reactions. However, the lack of a direct catalytic route from propane to propylene oxide reduces efficiency and represents a major challenge for catalysis science. Herein, we report the discovery of a highly active and selective catalyst, made of alumina-supported subnanometer copper clusters, which can directly convert propane to propylene oxide at temperatures as low as 150 °C. Moreover, at higher temperatures, on the same catalysts, the selectivity is switched to propylene. Accompanying theoretical calculations indicate that partially oxidized and/or hydroxylated clusters have low activation energies for both propane dehydrogenation and propylene epoxidation pathways, enabling direct conversion with very high selectivity for propylene oxide. The discovery of a low-temperature catalyst that can convert propane directly to propylene oxide provides an important opportunity for the development of energy-efficient and economic catalysts for this industrially critical process. Similarly, when operating at higher temperatures, these catalysts are posed as potent oxidative dehydrogenation catalysts.. Authors: Halder, Avik [Argonne National Laboratory (ANL), Argonne, IL (United States)]; Warburton, Robert E. [Purdue University, West Lafayette, IN (United States); Case Western Reserve University, Cleveland, OH (United States)] (ORCID:000000029693307X); Sun, Geng [University of California, Los Angeles, CA (United States)]; Cheng, Lei [Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000239021680); Assary, Rajeev S. [Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000295713307). DOE Contract: AC02-06CH11357; SC0014664; SC0019152. Subjects: 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; alkyls; catalysts; copper; density functional calculations; epoxidation; metal clusters; organic reactions; oxidative dehydrogenation; oxides; propane; propylene; propylene oxide; subnanometer clusters