Effect of Heating Temperature and Time on the Volatile Oxidative Decomposition of Linolenate

Ethyl linolenate, was thermally oxidized at 70°C, 180°C, 250°C in a closed system in the presence of atmospheric oxygen. On the basis of the peroxide curve obtained at each of the three temperatures, three heating times were chosen for the analysis of the volatile decomposition products. These products were identified by gas chromatography‐mass spectrometry. The qualitative pattern of the volatile decomposition products was the same for all treatments. Nine of the products were consistent with compounds predicted from cleavage of the conjugated linolenate hydroperoxides, with the C9 oxo‐ester and the C8 ethyl ester produced in the largest amounts. Other predicted products were not detected and were hypothesized to undergo further degradations. Although the major effect of temperature was found to be a quantitative one, it was difficult to relate the amounts of oxidation products directly to a temperature‐ dependent preferential hydroperoxide scission.