Exploiting basic principles to control the selectivity of the vapor phase catalytic oxidative cross-coupling of primary alcohols over nanoporous gold catalysts

Journal Article · Wed May 20 00:00:00 EDT 2015 · Journal of Catalysis

DOI:https://doi.org/10.1016/j.jcat.2015.04.022· OSTI ID:1416498

Wang, Lu-Cun ^[1]; Stowers, Kara J. ^[1]; Zugic, Branko ^[1]; Personick, Michelle L. ^[1]; Biener, Monika M. ^[2]; Biener, Juergen ^[2]; Friend, Cynthia M. ^[3]; Madix, Robert J. ^[4]

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1. Harvard Univ., Cambridge, MA (United States). Dept. of Chemistry and Chemical Biology
2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Nanoscale Synthesis and Characterization Lab.
3. Harvard Univ., Cambridge, MA (United States). Dept. of Chemistry and Chemical Biology, School of Engineering and Applied Sciences
4. Harvard Univ., Cambridge, MA (United States). School of Engineering and Applied Sciences

It is important to achieve high selectivity for high volume chemical synthesis in order to lower energy consumption through reduction in waste. Here, we report the selective synthesis of methyl esters—methyl acetate and methyl butyrate—through catalytic O₂-assisted cross-coupling of methanol with ethanol or 1-butanol using activated, support-free nanoporous gold (npAu). Both well-controlled studies on ingots in UHV and experiments under ambient pressure catalytic conditions on both ingots and microspherical hollow shell catalysts reveal guiding principles for controlling selectivity. Under UHV conditions, the ester products of the cross-coupling of methanol with both ethanol and 1-butanol evolve near room temperature in temperature-programmed reaction studies, indicating that the reactions occur facilely. Furthermore, under steady-state catalytic operation, high stable activity was observed for cross-coupling in flowing gaseous reactant mixtures at atmospheric pressure and 423 K with negligible combustion. Optimum selectivity for cross-coupling is obtained in methanol-rich mixtures due to a combination of two factors: (1) the relative coverage of the respective alkoxys and (2) the relative facility of their β-H elimination. The relative coverage of the alkoxys is governed by van der Waal’s interactions between the alkyl groups and the surface; here, we demonstrate the importance of these weak interactions in a steady-state catalytic process.

• Research Organization: Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Energy Frontier Research Centers (EFRC) (United States). Integrated Mesoscale Architectures for Sustainable Catalysis (IMASC)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC52-07NA27344; SC0012573
• OSTI ID: 1416498
• Alternate ID(s): OSTI ID: 1252811
• Report Number(s): LLNL-JRNL-737633; TRN: US1800941
• Journal Information: Journal of Catalysis, Vol. 329, Issue C; ISSN 0021-9517
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
Nanoporous gold
Oxidation
Methyl ester synthesis
Selectivity
Reaction mechanism
Heterogeneous catalysis