STRUCTURES OF OZONOLYSIS PRODUCTS OF METHYL OLEATE OBTAINED IN A CARBOXYLIC-ACID MEDIUM

High-performance liquid chromatography-mass spectrometry (LC-MS) and n uclear magnetic resonance spectrometry (NMR) were applied to the analy sis of organic peroxide mixtures, which were labile and tended to deco mpose 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 react ion products were directly analyzed by LC-MS equipped with a frit-fast atom bombardment interface. The molecular ion peak of each peroxide w as 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. Bot h results indicated that the reaction products include four peroxidic species: 1,2,4-trioxolane I, peroxide oligomer II, 1-acyloxyalkyl-1-hy droperoxide III, and 1-acyloxyalkyl-1'-hydroxyalkyl peroxide IV, as we ll as an aldehyde V. Ozonolysis of methyl oleate in the absence of sol vent produces mainly I, while that in the presence of a carboxylic aci d solvent characteristically produces mainly III and IV derived from t he solvent. Bis(1-acyloxyalkyl-1-alkyl) peroxide, which was reported p reviously as a ozonolysis product of methyl oleate, was concluded to b e IV in this study.