Controlling factors in deoxygenation kinetics and selectivity: Reactions of ethylene oxide on Mo(110)

Journal Article · Wed Aug 02 04:00:00 EDT 1989 · Journal of the American Chemical Society; (USA)

DOI:https://doi.org/10.1021/ja00198a008· OSTI ID:7071292

Serafin, J G; Friend, C M ^[1]

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1. Harvard Univ., Cambridge, MA (USA)

Ethylene oxide intramolecularly eliminates ethylene directly into the gas phase at 200 K (E{sub a} {approximately} 12 kcal/mol) during reaction on Mo(110) with 70% efficiency as shown by temperature-programmed reaction and x-ray photoelectron spectroscopy. Atomic oxygen, a product of this reaction, increases the rate of ethylene formation by slowing the kinetics for the competing nonselective decomposition pathway which accounts for the other 30% of reaction of chemisorbed ethylene oxide. The nonselective decomposition products of reaction are gaseous dihydrogen, surface carbon, and oxygen. At high ethylene oxide exposures, a small amount of molecular desorption is also observed at 150 K. Deposition of an atomic oxygen overlayer ({theta}{sub 0} {approximately}0.27) on Mo(110) prior to reaction enhances the selectivity of the ethylene formation reaction to 90%. Reaction saturation is controlled by the buildup of hydrocarbon fragments on clean Mo(110) and by oxygen site blocking on the oxygen precovered surface as shown by isothermal reaction spectroscopy. Carbon-heteroatom bond strength correlates with the temperature of ethylene formation in comparing reaction of ethylene oxide to that of the sulfur-containing analogue, ethylene sulfide, on Mo(110).

• DOE Contract Number: FG02-84ER13289
• OSTI ID: 7071292
• Journal Information: Journal of the American Chemical Society; (USA), Journal Name: Journal of the American Chemical Society; (USA) Vol. 111:16; ISSN 0002-7863; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204 -- Ceramics
Cermets
& Refractories-- Physical Properties
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALKENES
CATALYSIS
CHEMICAL REACTION KINETICS
CRYSTALS
DATA
DATA ANALYSIS
ELEMENTS
EPOXIDES
ETHYLENE
EXPERIMENTAL DATA
HYDROCARBONS
INFORMATION
KINETICS
LOW TEMPERATURE
MEASURING INSTRUMENTS
MEASURING METHODS
METALS
MOLYBDENUM
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
REACTION KINETICS
TRANSITION ELEMENTS