Baeyer-Villiger oxidation of cyclohexanone catalyzed by bifunctional Mg2Fe layered double hydroxide

Mg2Fe layered double hydroxide was prepared by the coprecipitation method and was used as an efficient catalyst for the Baeyer-Villiger oxidation of cyclohexanone to caprolactone in the presence of molecular oxygen and benzaldehyde. The obtained catalyst was characterized by XRD, FTIR, SEM, TG, XPS, and Hammett indicator method. The effects of solvent, benzaldehyde dosage. reaction temperature, O2 flow rate, catalyst dosage, and reaction time on the reaction were examined. Mg2Fe-LDH catalyst shows good catalytic results in the catalytic process which could also selectively convert a variety of cyclic ketone derivatives to their corresponding lactone with high yields. A series of controlled experiments were conducted to reveal the reaction mechanism. The results imply that the catalyst is bifunctional, possessing both alkalinity and redox properties. The alkalinity of Mg2Fe-LDH catalyzes the oxygen transfer from perbenzoic acid to cyclohexanone, iron with its highest oxidation state could catalyze the autoxidation of benzaldehyde to perbenzoic acid. In addition, the catalysts can be reused at least five times without significant decrease in catalytic activity.