Surface-mediated isomerization and oxidation of allyl alcohol on Cu(110)

Journal Article · Wed Jun 21 00:00:00 EDT 1989 · Journal of the American Chemical Society; (USA)

DOI:https://doi.org/10.1021/ja00195a003· OSTI ID:7157829

Brainard, R L; Peterson, C G; Madix, R J ^[1]

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1. Stanford Univ., CA (USA)

Allyl alcohol reacts with clean and oxygen-covered Cu(110) surfaces to produce propanal, acrolein, n-propyl alcohol, and hydrogen under ultrahigh-vacuum conditions. Very small amounts of propylene and water are also formed. This pattern of reactivity contrasts sharply to the selective oxidation to acrolein observed on Ag(110). On the clean Cu(110) surface allyl alcohol undergoes O-H cleavage to form the surface alkoxide CH{sub 2}{double bond}CHCH{sub 2}O{sub (a)} and H{sub (a)}. The results suggest that the olefin in this species undergoes partial hydrogenation to the surface-bound oxametallacycles ({minus}CH{sub 2}CH{sub 2}CH{sub 2}O-){sub (a)} and ({minus}CH-(CH{sub 3})CH{sub 2}O-){sub (a)} and complete hydrogenation to CH{sub 3}CH{sub 2}CH{sub 2}O{sub (a)}. Propanal forms at 320 K via further reaction of these oxametallacycles. Evidence for a {pi}-bonded allyl oxide CH{sub 2}{double bond}CHCH{sub 2}O{sub (a)}, which is more stable than n-propoxide (CH{sub 3}CH{sub 2}CH{sub 2}O{sub (a)}) toward {beta}-hydride elimination, is presented. This allyl oxide decomposes at 370 K to form acrolein. The interaction of the double bond with the surface apparently restricts the interaction of the {beta}-C-H bond with the surface and increases the stability of this species. Propanal, acrolein, and H{sub 2} are formed at 435 K by a process thought to involve the thermal decomposition of ({minus}CH{sub 2}CH{sub 2}CH{sub 2}O-){sub (a)} by a {beta}-hydride elimination pathway. This dehydrogenation pathway exhibits an activation energy 8 kcal/mol greater than for acyclic alkoxides. The conversion of allyl alcohol to propanal and propyl alcohol obviously involves the hydrogenation of the double bond which, by comparison, does not occur for propylene coadsorbed with hydrogen under similar conditions on this surface.

• OSTI ID: 7157829
• Journal Information: Journal of the American Chemical Society; (USA), Vol. 111:13; ISSN 0002-7863
• Country of Publication: United States
• Language: English

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36 MATERIALS SCIENCE
37 INORGANIC
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ALCOHOLS
ISOMERIZATION
OXIDATION
COPPER
DATA ANALYSIS
EXPERIMENTAL DATA
HYDROGEN
MEASURING INSTRUMENTS
MEASURING METHODS
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NUMERICAL DATA
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