Structures of ozonolysis products of methyl oleate obtained in a carboxylic acid medium

High‐performance liquid chromatography‐mass spectrometry (LC‐MS) and nuclear magnetic resonance spectrometry (NMR) were applied to the analysis of organic peroxide mixtures, which were labile and tended to decompose during analysis. The ozonolysis reaction of methyl oleate gives a peroxide mixture, and, finally, mono‐ and dibasic acids are obtained by subsequent oxidation. In this study, methyl oleate was ozonized in a nonanoic acid medium, one of the final reaction products. The reaction products were directly analyzed by LC‐MS equipped with a frit‐fast atom bombardment interface. The molecular ion peak of each peroxide was clearly observed, and its molecular weight was readily determined. On the other hand, each peroxide was fractionated by high‐performance liquid chromatography and submitted to structural analysis by NMR. Both results indicated that the reaction products include four peroxidic species: 1,2,4‐trioxolane I , peroxide oligomer II , 1‐acyloxyalkyl‐1‐hydroperoxide III , and 1‐acyloxyalkyl‐1′‐hydroxyalkyl peroxide IV , as well as an aldehyde V . Ozonolysis of methyl oleate in the absence of solvent produces mainly I , while that in the presence of a carboxylic acid solvent characteristically produces mainly III and IV derived from the solvent. Bis (1‐acyloxyalkyl‐1‐alkyl) peroxide, which was reported previously as a ozonolysis product of methyl oleate, was concluded to be IV in this study.