Graphite as a highly efficient and stable catalyst for the production of lactones

The carbon materials carbon nanotubes (CNTs), graphite, and activated carbon were tested as metal-free catalysts. They showed excellent activity and selectivity in the Baeyer–Villiger (B–V) oxidation of cyclohexanone at room temperature using dioxygen (O2) as oxidant and benzaldehyde as sacrificial agent. Among them graphite was found to be the most suitable for the formation of lactones from cyclic ketones, showing good recyclability and reusability. The use of the metal-free catalysts enables a green process for the production of lactones from ketones under mild reactions.