The oxidation of copper catalysts during ethylene epoxidation

Citations of this article
Mendeley users who have this article in their library.


The oxidation of copper catalysts during ethylene epoxidation was characterized using in situ photoemission spectroscopy and electron microscopy. Gas chromatography, proton-transfer reaction mass spectrometry and electron-ionization mass spectrometry were used to characterize the catalytic properties of the oxidized copper. We find that copper corrodes during epoxidation in a 1:1 mixture of oxygen and ethylene. The catalyst corrosion passes through several stages, beginning with the formation of an O-terminated surface, followed by the formation of Cu<inf>2</inf>O scale and eventually a CuO scale. The oxidized catalyst exhibits measurable activity for ethylene epoxidation, but with a low selectivity of <3%. Tests on pure Cu<inf>2</inf>O and CuO powders confirm that the oxides intrinsically exhibit partial-oxidation activity. Cu<inf>2</inf>O was found to form acetaldehyde and ethylene epoxide in roughly equal amounts (1.0% and 1.2% respectively), while CuO was found to form much less ethyl aldehyde than ethylene epoxide (0.1% and 1.0%, respectively). Metallic copper catalysts were examined in extreme dilute-O<inf>2</inf> epoxidation conditions to try and keep the catalyst from oxidizing during the reaction. It was found that in feed of 1 part O<inf>2</inf> to 2500 parts C<inf>2</inf>H<inf>4</inf> (PO<inf>2</inf> = 1.2 × 10<sup>-4</sup> mbar) the copper surface becomes O-terminated. The O-terminated surface was found to exhibit partial-oxidation selectivity similar to that of Cu<inf>2</inf>O. With increasing O<inf>2</inf> concentration (>8/2500) Cu<inf>2</inf>O forms and eventually covers the surface.




Greiner, M. T., Jones, T. E., Johnson, B. E., Rocha, T. C. R., Wang, Z. J., Armbrüster, M., … Schlögl, R. (2015). The oxidation of copper catalysts during ethylene epoxidation. Physical Chemistry Chemical Physics, 17(38), 25073–25089.

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free