Isomerisation of unsaturated fatty acid esters. Part II: Location of double bonds by oxidative degradation methods

For the location of the double bonds in di‐ethenoid acids, ozonolysis is recommended in preference to degradation with KMnO 4 , as the former method leads to a higher yield of the primarily formed mono‐ and di‐carboxylic acids and the latter method may result in the formation of interfering secondary degradation products. By subjecting some pure dicarboxylic acids or their half‐esters to the action of the oxidising agents Ag 2 O or KMnO 4 , it was found that the latter causes a fairly considerable secondary degradation of the higher homologues.