Study On Synthesis Of Caprolactone By Cyclohexanone Oxidation Using Co-based Heterogeneous Catalysts

ε-Caprolactone is an important intermediate for organic synthesis and is a newnontoxic monomer used to synthesize poly(caprolactone). ε-Caprolactone isconventionally synthesized by the the oxidation of cyclohexanone in Baeyer-Villiger(B-V) reaction. The organic peracids as the oxidizing agents in traditional B-Vreaction exist some challenges such as high cost, no safety and severe environmentalcontamination. Many catalysts have been reported with low acitivity, selectivity, andpoor stability. Therefore, it is highly desired to use clean dioxygen as oxidant and todevelop effective catalysts for synthesis of ε-caprolactone.In this thesis, different catalysts were tested for the oxidation of cyclohexanoneto ε-caprolactone. Compared with the Fe2O3, MnO2, SnO2and others, the Co3O4catalyst exhibited highest catalytic activity in this reaction. In addition, the influencesof reaction solvent, reaction time, reaction temperature and catalyst loading upon theoxidation of cyclohexanone to ε-caprolactone in the presence of Co3O4catalyst wereinvestigated. In order to clarify the relationship between the structure and catalyticperformance, different techniques were employed to characterize the catalysts, suchas SEM, XRD and BET. It was found that larger pore volume and pore size wasbeneficial for improving the catalytic performance. Moreover, it was found that theCo3O4showed high catalytic efficiency towards the oxidation of various ketones tolactones.On the basis of the previous work of Co3O4catalyst, another new catalystCo-MFI was prepared by direct hydrothermal synthesis (DHT) and applied to theoxidation of Cyclohexanone to ε-caprolactone. The effects of solvent, reaction time,reaction temperature and oxidizing agent were also studied. Under the optimalreaction conditions, cyclohexanone conversion and ε-caprolactone selectivity reach90.7%and100%, respectively. The morphology of this catalyst presented regular6-prism shape with average particle size approximately400nm. The catalystexhibited excellent catalytic activity in the oxidation of cyclic ketones to lactoneswith dioxygen and benzaldehyde.