Periodate-permanganate oxidations. IV. Determination of the position of double bonds in unsaturated fatty acids and esters

The reaction of the periodate-permanganate reagent with unsaturated fatty acids, including oleic, elaidic, eicosenoic, 10-undecenoic, and linoleic acids proceeded smoothly to give the expected end-products in quantitative yields. The latter were conveniently isolated and determined by partition chromtography on silicic acid columns in 10 to 100 mgm. quantities. Some compounds, which were unreactive due to insolubility in the reagent, gave satisfactory results when the media contained 5 to 10% of pyridine. This was true also for methyl linoleate even though solution was incomplete. However methyl oleate and triolein did not give quantitative results even in media containing 20% or more of pyridine in which the esters were completely dissolved.