Reactions of fatty materials with oxygen. XV. Formation of 9,10-dihydroxystearic acid and cleavage products in the oxidation of oleic acid and methyl oleate in acetic acid

Summary The autoxidation of oleic acid and methyl oleate in acetic acid solution at 25–30°, 65°, and 115–120° with a cobalt salt as catalyst has been studied. Samples were withdrawn at intervals and the oxidation products were analyzed and then separated into high-melting 9,10-dihydroxystearic acid, cleavage products, unoxidized and hydroxy materials, and polymers. The best yields of desired oxidation products were obtained at 65°. Yields of pure 9,10-dihydroxystearic acid, m.p. ≧128°, were 12–17% and cleavage products 64–68%, thus accounting for about 80% of the starting material. At 25–30° and 115–120°, yields of the above-mentioned products were low. A mechanism is proposed which accounts for the formation oftrans-9,10-epoxystearic acid from both oleic and elaidic acid autoxidized in the absence of solvent, and the consequent isolation of high-melting 9,10-dihydroxystearic acid when acetic acid is the solvent. Paper XIV is reference 10. Presented at the Fall Meeting of the American Oil Chemists’ Society, Chicago, Ill., Nov. 2–4, 1953. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Service, U. S. Department of Agriculture.