Study On The Catalytic Systems For The Baeyer- Villiger Oxidation Of Cyclic Ketones

Lactones can be synthesized by Baeyer-Villiger oxidation of cyclic ketones, and these lactones are the important intermediates of dyes,pesticides and drugs, so that many people trying to find an effective method for the catalytic processes of cyclic ketones to lactones all the time. Peracid was the traditional oxidant used for the reaction, but it is unsafety during the reaction process and transportational process. So it was substituted by hydrogen peroxide which byproduct was water. However, the potential safety hazard of hydrogen peroxide is exists when its concentration exceed 70%. Many kinds of catalyst also have been used for the Baeyer-Villiger oxidation, such as hydrotalcite-like material, acid catalyst, ligand compounds, transition metal complexes and bio-enzyme. However, most of the catalysts were difficult to synthesize with high-cost, and the reaction conditions were unfriendly for environment. The bio-enzyme with high selectivity should control the reaction conditions strictly; therefore, it is urgent to explore effective and environmental catalysts with high catalytic activity for the Baeyer-Villiger oxidation under mild conditions. In this paper, in order to solve the defect of the exiting catalyst and oxidant, we used cyclic ketones as substrate, trying two different catalytic oxidation systems for its Baeyer-Villiger oxidation.First, supported cobalt phthalocyanine and supported nickle phthalocyanine were synthesized, and both of them were characterized by EDX, XRD. Then we used them as catalyst, molecular oxygen as oxidant and benzaldehyde as pro-oxidant were used for the Baeyer-Villiger oxidation. Reaction conditions, which were optimized by single factor experiments, namely cyclohexanone 0.05mol, benzaldehyde 0.1 mol,1,2-dichloroethane 50ml, temperature 15℃, the quality ratio of catalyst amount/cyclohexanone was 0.05, reaction time was 12h, with the conversion of cyclohexanone 92.6%. Many kinds of cyclic ketones were catalyzed under the optimal conditions with high conversion.Second, upported copper chloride was prepared, and was characterized by XRD, EDX. Then we used them as catalyst, benzaldehyde/O2 as oxidant for the Baeyer-Villiger oxidation. Reaction conditions were optimized, namely cyclohexanone 0.025mol, benzaldehyde 0.05mol, 1,2-dichloroethane 25ml, temperature 25℃, the quality ratio of catalyst amount/cyclohexanone was 0.024; reaction time was 12h, with the conversion of cyclohexanone 96.2%. Many kinds of cyclic ketones were catalyzed under the optimal conditions.