FTIR spectroscopic study of the OH-induced oxidation of two linear acetates: ethyl and n-propyl acetates

OH-induced oxidation mechanisms of ethyl and n-propyl acetates have been in vestigated at room temperature (298 +/-5 K) and atmospheric pressure by pho tolysing CH3ONO/acetate/NO mixtures with FTIR spectroscopy as analytical de vice. The main oxidation products and their yields were as follows: from et hyl acetate, acetic acid (0.75 +/-0.13), acetoxyacetaldehyde (0.15 +/-0.05) , acetic anhydride (0.02 +/-0.01), formic acetic anhydride (0.02 +/-0.01) a nd peroxyacetyl nitrate (PAN); from n-propyl acetate, acetoxyacetaldehyde ( 0.22 +/-0.06), formic acetic anhydride (0.28 +/-0.03), acetic acid (0.15 +/ -0.02), acetaldehyde (0.35 +/-0.10), peroxypropionyl nitrate (PPN) and prob ably acetoxypropionaldehyde (0.30 +/-0.10). From these data, oxidation sche mes of these two acetates were elucidated. This study reveals in particular the specific reactivity of acetates by confirming the novel alpha -ester r earrangement proposed recently by Tuazon et al. (J. Phys. Chem. A, 1998, 10 2, 2316) and then by showing that oxygenated alkoxyl radicals may not follo w the same rules of reactivity as other alkoxyl radicals. This last observa tion shows the necessity for further experiments to understand the influenc e of the oxygenated function on alkoxyl reactivity.