Oxygen-assisted cross-coupling of methanol with alkyl alcohols on metallic goldElectronic supplementary information (ESI) available: Mass spectrometry data. See DOI: 10.1039/c0sc00214cSupport of this work by the U.S. Department of Energy, Basic Energy Sciences, under grant No. DE-FG02-84-ER13289 is gratefully acknowledged. JH also acknowledges support of the Alexander von Humboldt Foundation through a Feodor Lynen fellowship

• Main Authors: Xu, Bingjun, Haubrich, Jan, Freyschlag, Cassandra G, Madix, Robert J, Friend, Cynthia M
• Format: Article
• Language: English
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/c0sc00214c

We demonstrate for the first time that selective cross-coupling of methanol with either ethanol or n -butanol occurs below room temperature on metallic gold with no metal oxide support in a reaction sequence that occurs entirely on the surface. The esterification proceeds via activation of the alcohols by adsorbed oxygen and a sequence of reactions that involve both surface-bound alkoxys and hemiacetals as intermediates. The reaction selectivity is dictated by competing β-hydride elimination from the alkoxys. Due to the higher activation energy for β-hydride elimination from methoxy, no formate esters are formed. A molecular-scale mechanism constructed using our results is in excellent agreement with studies of heterogeneous catalysts, providing insight into selectivity control under a broad range of conditions. We demonstrate for the first time that selective cross-coupling of methanol with either ethanol or butanol occurs below room temperature on metallic gold with no metal oxide support in a reaction sequence that occurs entirely on the surface.