PRODUCTS OF DIMERIZATION OF UNSATURATED FATTY-ACIDS .5. THE AROMATIC FRACTION OF DIMERIC ACIDS

The aromatic fraction of dimeric fatty acid esters can be separated according to a decreasing grade of unsaturation by HPLC using an UV-recorder. Hydrogenation experiments of the collected fractions allowed the determination of the number of rings. If the aromatic fractions are oxidized with KMnO4 using a phase-transfer catalyst benzene 1,2,4- and 1,3,5-tri-, 1,2,4,5- and 1,2,3,5-tetra- and the pentacarboxylic acid were obtained as main products. Consequently we have to conclude that the catalyst causes intramolecular extensive migration of alkyl chains. Finally 2,3-dihydrobenzofurantetracarboxylic acids with different position of the carboxylic groups were detected in the mixture of oxidation products.