Epoxidation of unsaturated fatty acid ester promoted by imidazolium acidic ionic liquids: An unexpected selectivity phenomena

Abstract Epoxidation of linseed oil fatty acid ethyl esters promoted by a series of functionalized imidazolium ionic liquids was studied. In this reaction acidic imidazolium ILs behave not only as an acid catalysts but also play an additional role as a specific activator for the reaction of epoxidation of unsaturated fatty derivatives in H 2 O 2 /formic acid oxidation system. The obtained results indicate that the hydrogen‐bonding interaction of imidazolium cation with epoxide group influences the selectivity of the epoxidation reaction. In particular, the presence of unprotected weak “acid” C2‐H proton significantly lowers the selectivity to hydroxyl derivatives. The obtained results also point to another example of specific polyfunctionality of ILs, especially imidazolium one, used as surfactants and process activators.