Evidence for hydroperoxide formation in the autoxidation of methyl linolenate

Summary 1. The results of chemical, spectral, and distillation analyses on the isolated oxidized fractions of three samples of methyl linolenate autoxidized at 0°C. to peroxide values from 600 to 760 m.e./kg. indicated that about 60% of the products consisted of cis,transconjugated diene methyl octadecatrienoate-monohy-droperoxide. 2. A product was isolated from the reduced peroxide concentrates which consisted of about 90% cis,trans- conjugated diene methyl monohydroxyoctadecatrienoate. 3. Analytical micromolecular distillation analyses showed that the total oxidized material isolated from samples of autoxidized methyl linolenate contained only about 15% polymeric material under the conditions of autoxidation employed in this study. 4. Linolenate was shown to be similar to linoleate in forming a cis,trans-conjugated monomeric monohydroperoxide as a major initial product of autoxidation at 0°C. This work was supported in part by a contract between the Office of Naval Research, Department of the Navy, and the University of Minnesota. It was presented at the spring meeting of the American Oil Chemists’ Society, New Orleans, May, 1953.