Aerobic Baeyer-Villiger oxidation of ketones over Cu heterostructure surface in the presence of benzaldehyde: the effect of valence state Manisha Shaw, Amita Pathak Indian Institute of Technology, India The catalytic oxidation of simple cyclic ketone to lactones, are in demand for the preparation of biomedical polymers. Lactones are traditionally produced through Baeyer-Villiger oxidation of cyclic ketone by peracids in industry, which inevitably results in environmental pollution. Considering their toxicity, it is meaningful to develop a green route for the production of lactones. In this work, lactone was produced by the in situ generation of peracids during the aerobic Baeyer-Villiger oxidation of cyclohexanone, in the presence of benzaldehyde used as a sacrificial agent, over the surface of Cu based heterostructures in one pot. The generally accepted reaction scheme for the O 2 /aldehyde oxidation system involves two step, the first step includes the in situ peracid formation and the second step includes the oxidation of the reactant by the formed peracid in the reaction solution. Several Cu based heterostructure with varying morphology were tested for the oxidation of cyclohexanone to ε-caprolactone, and it was found that Cu 2 O/Cu showed the highest catalytic activity, over 90% of ε-caprolactone yield at 30 °C attributed to the effect of mixed valence state of Cu or their combination. Experimental work further provided evidence for the existence of such mixed-valence Cu species. A catalyst control experiment suggests that the Cu 2 O/Cu catalyst played the role for the adsorption and activation of in situ generated peracid, in the presence of aldehyde and molecular oxygen. Mechanistic study suggests that peracid species produced by a series of chain propagation reactions is the key intermediate, and the Cu 2 O/Cu catalyst contributes to high aldehyde efficiency by buffering the radical species, which are essential for the higher conversion and yield of the reactions. References
1. htps://www.sciencedirect.com/science/article/pii/S2468823118302918 2. https://pubs.rsc.org/en/content/articlelanding/2020/ra/d0ra03335a 3. https://pubs.acs.org/doi/full/10.1021/cs3007928
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