Secondary reactions of methyl radicals with lanthanide oxides: Their role in the selective oxidation of methane

Journal Article · Thu Apr 20 00:00:00 EDT 1989 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100345a012· OSTI ID:5111034

Tong, Youdong; Rosynek, M P; Lunsford, J H ^[1]

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1. Texas A and M Univ., College Station (USA)

Reactions between methyl radicals and certain members of the lanthanide oxide series have been studied by using a matrix isolation electron spin resonance technique. Methyl radicals react extensively with the lanthanide-metal oxides CeO{sub 2}, Pr{sub 6}O{sub 11}, and Tb{sub 4}O{sub 7}, all of which have multiple cationic oxidation states. By contrast, the oxides La{sub 2}O{sub 3}, Nd{sub 2}O{sub 3}, Sm{sub 2}O{sub 3}, Eu{sub 2}O{sub 3}, and Yb{sub 2}O{sub 3} react with CH{sub 3}{sup {sm bullet}} radicals to only a small extent. Consistent with this observation, the former group of oxides is ineffective in the generation of CH{sub 3}{sup {sm bullet}} radicals which emanate into the gas phase. The reaction of CeO{sub 2} with CH{sub 3}{sup {sm bullet}} radicals is strongly inhibited by the addition of Na{sub 2}CO{sub 3}, and consequently radical production is enhanced. This effect is manifested in the catalytic properties of CeO{sub 2}, which is a complete oxidation catalyst in its pure form but becomes a good catalyst for the oxidative coupling of methane following the addition of Na{sub 2}CO{sub 3}.

• OSTI ID: 5111034
• Journal Information: Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 93:8; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
ACTIVATION ENERGY
ALKANES
ALKYL RADICALS
CERIUM COMPOUNDS
CERIUM OXIDES
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DATA
EFFICIENCY
ELECTRON SPIN RESONANCE
ENERGY
EUROPIUM COMPOUNDS
EUROPIUM OXIDES
EXPERIMENTAL DATA
HYDROCARBONS
INFORMATION
KINETICS
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
MAGNETIC RESONANCE
MATRIX ISOLATION
METHANE
METHYL RADICALS
NEODYMIUM COMPOUNDS
NEODYMIUM OXIDES
NUMERICAL DATA
ORGANIC COMPOUNDS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PRASEODYMIUM COMPOUNDS
PRASEODYMIUM OXIDES
RADICALS
RARE EARTH COMPOUNDS
REACTION KINETICS
RESONANCE
SAMARIUM COMPOUNDS
SAMARIUM OXIDES
TERBIUM COMPOUNDS
TERBIUM OXIDES
YTTERBIUM COMPOUNDS
YTTERBIUM OXIDES