抄録
In this paper, on the ground of his experimental attainments as below, the auther claims that the usual permanent discoloration of aero-oxidized oleic acid is nothing, but the discoloration of acid carbonyl compounds, i.e., aldehydic- or ketonic-acids, as a constituent of the so-called oxidized acids born in the oleic acid.
Namely, to be mentioned in the first place, the author, fractionating the oxidized acids isolated from oleic acid having already suffered the advanced discolorarion, found that the constituents which were strongly colored in dark brown belonged solely to the fraction of carbonylic property, while as for the color tone of the non-carbonylic fractions hydroxylic acids were colorless and the remainder were found to be but of light orangish yellow.
In providing another support for his assertion, the author fractionated on the other hand oleic acid which had been oxidized to some extent but remained still prior to discoloration into fractions consisting respectively of non-carbonyl compounds, neutral carbonyl compounds, and acid carbonyl compounds; he examined the color development of these fractions after the routine procedure and confirmed that only the acid carbonyl compounds were possible to yield stably colored materials.
Finally, by means of 2, 4- dinitrophylhenydrazine it has been verified paper- chromatographically that azelaic acid half aldehyde and 9, 10- diketostearic acid exist actually in the acid carbonly fracion of oleic acid autoxidized in air. The details of the work, however, will be described in a succeeding paper.
