Study On Catalyst For Baeyer-Villiger Oxid-Ation Of Cyclohxanone To Caprol Actone With Hydrogen Peroxide

In 1899, Baeyer and Villiger first proposed Baeyer-Villiger oxidation,which mainly oxidated the cyclic ketone (menthone, carvone, camphor) by conventional peroxyacid (peracetic acid, concentrated sulfuric acid peroxide) to the corresponding lactone. Caprolactone was an important chemical intermediates, widely used in the synthesis of fine chemical products and played an irreplaceable role in the preparation and modification of new polymer materials aspect. In the conventional process, the synthesis of caprolactone need a strong oxidant, and harsh conditions, so far, only a few companies as Germany, and Japan and USA,which can be mass-produced, and other almost depended on import. Application of caprolactone in the market gradually had increased. Thus, the synthesis of the lactone had aroused dense interest.In this paper, catalytic ing cyclohexanone prepared caprolactone with environmentally friendly and low concentrations of H2O2 as the oxidant in three different catalytic oxidation catalytic system. The ZnCl2 as catalyst was used directly without any treatment. The catalyst was prepared with institutional complexes formed between the generation of sodium tungstate and oxalic acid. Using ion exchange method will take different amounts of Zn supported on zeolite molecular sieves ZSM-5, and then by XRF, FT-IR, BET, X-ray diffraction, H2-TPR and other means, which to characterize its structure. And in the reaction system, the catalytic activity was evaluated and optimized best Conditions.Zinc chloride had Lewis as a catalyst to catalyze the oxidation of cyclohexanone the results showed that:The conversion rate was 72.35% and the selectivity was 92.35%.which exhibited high catalytic performance and good cycling stability to achieve satisfactory results withouta solvent and phase transfer system.In industrial production, which had potential applications. Almost a simple mechanism divided into the following four steps:first step:carbonyl O atoms and Zn atoms formed a coordination, this will lead to the original charge ketone carbonyl group rearrangement occurred,resulting in the transfer of electrons in the original C atoms, it which will get activation to give intermediate A;The second step:After the C atom of ketone carbonyl been activated, the system was more vulnerable to attack molecules of H2O2 generated to Criegee adduct. Third step:Criegee adduct of rearrangement reaction got intermediate B;Last:since the decomposition of Intermediate B obtained the desired product of caprolactone.The result of the oxidation of cyclohexanone catalyzed whithout solvent system show:Factors of experiment optimized the results that reaction temperature 60?, H2O2 content of 0.30 mol, sodium tungstate:acid ratio of 2:3, the best time of 7 h, the catalyst activity to achieve the desired state.Substrate conversion rate was 53.80%, product of the selectivity of up to 92.20%. In the reaction solvent-free conditions and the optimal ratio between ligand complexes, which had a higher catalytic performance.The result of the oxidation of cyclohexanone Baeyer-Villiger catalytic by Zn/ZSM-5 indicate:By varying amounts of Zn/ZSM-5 obtained experimental data comparison, that the best catalyst activity of Zn/ZSM-5 (200%), The reaction temperature was 60?, the amount of catalyst 0.20 g, H2O2dosage 0.30 mol, the reaction time was 6 h. Under optimum reaction conditions, Zn/ZSM-5 catalytic ability into full play. The reaction conversion rate was 32.00%, the selectivity 62.00%, good stability due to the recycling of the catalyst,and the catalyst having a certain prospect.