SECONDARY REACTIONS OF METHYL RADICALS WITH LANTHANIDE OXIDES - THEIR ROLE IN THE SELECTIVE OXIDATION OF METHANE

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 CeO2, Pr6O11, and Tb4O7, all of which have multiple cationic oxidation states. By contrast, the oxides La2O3, Nd2O3, Sm2O3, Eu2O3, and Yb2O3 react with CH3* radicals to only a small extent. Consistent with this observation, the former group of oxides is ineffective in the generation of CH3* radicals which emanate into the gas phase. The reaction of CeO2 with CH3* radicals is strongly inhibited by the addition of Na2CO3, and consequently radical production is enhanced. This effect is manifested in the catalytic properties of CeO2, 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 Na2CO3. 1989 American Chemical Society.

SECONDARY REACTIONS OF METHYL RADICALS WITH LANTHANIDE OXIDES - THEIR ROLE IN THE SELECTIVE OXIDATION OF METHANE Academic Article