Relative yields of radicals produced in deuterated methanol by irradiation

• The deuteration of the methyl in methanol lead to a higher yield of the methoxy radical.
• The deuteration of the hydroxyl in methanol lead to a lower yield of the methoxy radical.
• The rates of proton transfer and hydrogen abstraction influence the relative radical yield.

The relative yields of radicals produced in four kinds of methanols; i.e., CH3OH, CH3OD, CD3OH and CD3OD, by γ-irradiation have been studied using ESR spin trapping with PBN. Both PBN-H and PBN-D were produced from CH3OD and CD3OH. This means that the proton transfer to the neutral methanol from the cationic one is one of the processes to produce both the methoxy and hydoxy-methyl radicals. The yield of the methoxy radical adduct relative to the hydroxy-methyl radical adduct decreased in the order CD3OH>CD3OD>CH3OH>CH3OD. The difference in the rates of the proton transfer and hydrogen abstraction reactions by substitution with deuterium is the reason for the variation in the relative radical yield.