Shifting of the double bond in methyl oleate during hydrogenation

Summary The displacement of the double bond of methyl oleate during hydrogenation with a nickel‐kieselguhr catalyst at 180°C. was investigated, particularly with respect to the analysis of dicarboxylic acids, obtained either by oxidation of the reaction products with KMnO 4 in acetic acid or by means of ozone. In the oxidation experiments with KMnO 4 a considerable degradation of lower molecular dicarboxylic acids occurs that makes a quantitative analysis of the isomerization phenomena uncertain. According to the ozonization experiments an equal migration of the double bond in both directions, toward and opposite the ester group, takes place.