Study On The Catalysis Of Cyclohexanol To Cyclohexanone

The cyclohexanone as an important fine chemicals and intermediate is widely used in production of fiber monomer, organic solvent, coating, adhesive, antioxidant, photosensitive material, medicine, pesticide and other fields. With the development of green chemistry, research on the synthesis of cyclohexanone from cyclohexanol draws high attention. In order to find a green, efficient and reusable catalytic system, a lot of research work has been made. The specific wok is as follows:1. To the reaction system that using heteropolytungstate K10P2W17O61.13H2 O as the catalyst and oxidizing cyclohexanol to cyclohexanone with hydrogen peroxide, the recovery and reusability of the catalyst were researched. The catalyst was characterized by infrared spectroscopy and X-ray diffraction, and the causes of the activity decline were analyzed.2. The carrier of molecular sieves, Ion-exchange resin, organic polymer, activated carbon, silica gel for K10P2W17O61.13H2 O was studied, and the catalytic actives were also investigated. The results demonstrated that silica gel as the carrier of catalyst was appropriate. The heteropolytungstate K10P2W17O61.13H2 O was supported on the silica gel with a new method. First, immobilizing phosphotungstic acid on the silochrom by reflux impregnation method, and then using ion exchange to make the K10P2W17O61.13H2O/Si O2. The supported catalyst catalytic oxidation of cyclohexanol to cyclohexanone. Study on the effects of amount of TBAB, reaction temperature, reaction time, the dosage of catalyst and hydrogen peroxide. The optimum reaction conditions as follows(based on 45 mmol cyclohexanol): reaction time 5 h, reaction temperature 90℃, n(H2O2):n(cyclohexanol)=6.5:1, catalyst 0.5 g and TBAB 0.05 g. In this condition, the yield of cyclohexanone could be reached 90.2 %.3. The new supported catalyst was compared with the conventional supported catalyst in the oxidation of cyclohexanol to cyclohexanone, the new supported catalyst shows high catalytic activity and stability in the process of repeated use. To analyze the new supported catalyst by infrared spectroscopy.4. The cyclohexanone was synthesized from cyclohexanol using the heteropolyphosphatotungstate Q3[PO4(WO3)4](Q= π-C5H5NC16H33) as the catalyst. The effects of amount of hydrogen peroxide and catalyst, reaction time and temperature were studied. By single factor experiments, the optimal reaction conditions were obtained(based on 45 mmol cyclohexanol): reaction temperature 70℃, n(H2O2):n(cyclohexanol)=2.5:1, catalyst 0.3 g and the reaction time 4 h. The yield of cyclohexanone was 95.6 % under this condition. After reaction, the catalyst was insoluble in the reaction system and could be recycled after simple filtration, and the yield of cyclohexanone was 91.3 % after the catalyst recycled for five times. The recovery rate of catalyst was above 88.7 %。5. The effects of TEMPO in the synthesis of cyclohexanone from cyclohexanol were studied, through orthogonal and single factor experiments, the optimum reaction conditions were obtained: cyclohexanol 3 mmol, CH2Cl2 7 m L, TEMPO 0.005 g, Na Cl O 0.45 g, Na Br 0.03 g, p H 9.1 and reaction time 60 min. Parallel experiments were performed three times in this condition, the average yield of cyclohexanone was 87.3 %.6. The result was proved that the synthetic product was the objective product. In order to analysis the product, the gas chromatogram, nuclear magnetic resonance, and infrared spectra analysis were used.