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Summary The thermal oxidation of corn oil proceeds in two steps, an initial period of 12 to 16 hrs., characterized by a decrease in iodine value and a rapid increase in carbonyl value, and a second phase in which a slower decrease in iodine value, a slight decrease in carbonyl value, and a rapid increase in viscosity occurred. Increasing the rate of aeration caused greater magnitude in changes but did not alter the over‐all two‐phase reaction.

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Summary Oxidative polymers which had been isolated from autoxidized ethyl linolenate were oxidatively decomposed in a closed system at room temperature. The decomposition products were collected in appropriate traps and separated into various fractions on the basis of their volatility and solubility. The aldehydes and ketones thus obtained were converted into 2,4‐dinitrophenylhydrazones, chromatographed on silica gel, and the isolated 2,4‐dinitrophenylhydrazones identified by standard procedures. Methyl ethyl ketone, propionaldehyde, acetaldehyde, and alpha‐pentenal were positively identified, and evidence for the presence of crotonaldehyde and an unknown five‐carbon‐carbonyl compound was obtained. Acetaldehyde, propionaldehyde, and alpha‐pentenal have been isolated from the decomposition products of oxidatively decomposed reverted soybean oil by previous workers. If oxidative polymers of linolenate are present in reverted soybean oil, they could serve as precursors of the aldehydes and ketones which have been associated with flavor reversion.