Oxidation of 13C-labeled ethyl linoleate monitored and quantitatively analyzed by 13C NMR

The oxidation of 13C-labeled ethyl linoleate (13C-EL), a model compound for alkyd resins, was investigated by 13C NMR in the presence of Co(II)-2-ethylhexanoate (Co-EH), Mn(acac)3 (acac = acetylacetonate), and Mn(acac)3 in combination with 2,2′-bipyridine (bpy), respectively. The use of 13C-EL allows us, in an unprecedented way, to reveal the individual evolution of hydroperoxides (ROOH) and peroxy (ROOR) links by 13C NMR and to quantify the oxidation intermediates during the oxidation. Mn(acac)3 appeared to be less effective in decomposing ROOH than Co-EH and the Mn(acac)3/bpy combination. Quantitative analyses were attempted for a few major 13C peaks.