The migration of double bonds during the isomerization of methyl linoleate with palladium on carbon catalyst

Summary The isomerization of methyl linoleate by heating with palladium on carbon catalyst gave an initial rapid rise in the degree of conjugation which reached a maximum and then gradually decreased. The maximum conjugation obtained was about 24% after 4 hrs. of heating at 200±5°C. with 25% by weight of catalyst. Ultraviolet absorption spectra did not indicate the presence of any cyclized aromatic components even after 46 hrs. of heating at 200°C. but showed the formation of aromatics at 250°C. The limit of conjugation obtained is a result of random migration of the olefinic bonds rather than dimerization or polymerization reactions.