Epoxidation of methyl oleate with molecular oxygen in the presence of aldehydes

The epoxidation of methyl oleate with molecular oxygen in the presence of aldehydes was investigated and optimized. Epoxide yields up to 99% were observed in organic solvents. The preponderant radical reaction was started by a single organic radical chain initiator, without using a metal catalyst. The radical character of the reaction was revealed by the concurrent occurrence of trans and cis epoxides and by the prevention of epoxide formation through a radical scavenger. Both branched aldehydes and the linear aldehyde n ‐hexanal were well suited in organic solvents. The linear n ‐hexanal enabled also a superior epoxide yield of 78% in the green solvent water. The oxidation of high‐oleic sunflower oil under the same conditions with n ‐hexanal yielded 39% epoxide groups.