Intermediates in the Chlorine-sensitized Photo-oxidation of Methane

BOTH methyl radicals and hydrogen atoms have been proposed as chain-carriers in the photo-chlorination of methane1,3; and, although the former are generally favoured, in neither case has direct evidence been produced4. However, the theoretical heat content change of the corresponding partial reaction would be approximately zero, if methyl radicals were involved, but endothermic by 21 kcal./mole, on the basis of hydrogen atom formation.