Fatty ketones from the rearrangement of epoxidized vegetable oils

The rearrangement of epoxidized vegetable oils to produce fatty ketones, catalyzed by acidic resins, is disclosed. The non-microbial production of fatty ketones from epoxidized vegetable oils has not been previously reported. Some of the variables affecting the ketone formation such as acidic strength of the catalyst, temperature and solvent are studied in order to determine the conditions that favor the rearrangement. Epoxidized vegetable oils can be easily transformed to the respective ketones via a rearrangement reaction catalyzed by acidic resins. Other kind of acidic catalysts are active for this reaction if their Brönsted acid sites are accessible to protonate the epoxide. Formation of ketones, from the rearrangement of epoxidized methyl oleate, is favored in the presence of strongly acidic catalysts and enhanced by increasing temperature. Polar-protic solvents increase the ketone yield but decrease the ketone selectivity because they are added to the epoxide ring. The mechanism for the epoxide rearrangement is very likely to take place through a hydride migration to the carbocation generated in the acid-catalyzed epoxide ring opening.

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► Epoxidized vegetable oils can be transformed to ketones via rearrangement reaction.
► Acid catalysts are active if their Brönsted acid sites are accessible.
► Formation of ketone is favored by strong acidic catalysts and temperature.
► Polar-protic solvents increase the ketone yield but decrease the selectivity.
► Epoxide rearrangement takes place through a hydride migration.