Selective oxidation of ethanol over Ag, Cu and Au nanoparticles supported on Li2O/γ-Al2O3.

In an effort to verify a previous striking report that ethanol could be oxidized selectively to ethylene oxide, ethanol oxidation on Ag, Cu, or Au nanoparticles supported on Li 2 O/γ-Al 2 O 3 or γ-Al 2 O 3 was examined between 100 and 400 °C. Ag and Cu catalysts were found to be highly selective to acetaldehyde (>95% on Ag below 325 °C and on Cu below 250 °C). On Au, selectivities to acetaldehyde were lower, with higher selectivity to ethyl acetate and acetic acid. No ethylene oxide was observed under any conditions. Our results, including selectivity variations among these metals, are consistent with previous studies of ethanol oxidation over coinage metals supported on γ-Al 2 O 3 , with no changes in primary product identity and minor changes in selectivity upon addition of Li 2 O. Unfortunately, these results are in direct contradiction to previous work reporting the desirable direct conversion of ethanol to ethylene oxide on Ag, Cu, and Au on Li 2 O/γ-Al 2 O 3 . [ABSTRACT FROM AUTHOR]