Catalytic Oxidation Of Cyclohexane Over Meta-Aluminic Acid Supported Tetra(4-caboxyl Or Pentafluoro Phenyl) Metalloporphyrins

Catalytic oxidation of cyclohexane to K/A oil is of great importance in organic reaction. Metalloporphyrins have been studied for using as a model of monoxygenase enzymes, the Cytochrome P-450, and widely employed in catalysis for oxidation of alkanes. However, it is pity that expensive metalloporphyrins in homogeneous catalysis system can not be reused further, resulting in high cost in practical industry. Therefore, it is necessary to study on supported metalloporphyrins. At the same time, a lot of literatures at home and abroad have reported that the second and third generations of metalloporphyrins with electron-withdrawing substituents shows higher catalytic activity for the oxidation of alkane than the first. In my thesis based on this reason, tetra (4-carboxyl or pentafluoro phenyl)metalloporphyrins supported on meta-aluminic acid(MAA) were prepared and used for catalytic oxidation of cyclohexane with air. The subsequent results are compared with each other and with those catalytic activities for the aerobic oxidation of cyclohexane over the three unsupported corresponding catalysts. A hypothetic mechanism for the catalytic oxidation was also discussed. A main contents of my thesis are as follows:1. A current development on research in catalytic oxidation of cyclohexane at home and abroad and a progress for application of supported metalloporphyrins in catalytic oxidation of hydrocarbon are briefly summarized. A main content for my thesis and its significance have been presented.2. Cobalt meso-tetra(4-carboxylphenyl)porphyrin[Co TCPP] and iron meso-tetra(4-carboxylphenyl)porphyrin[Fe TCPP] were synthesized according to relative literatures and then Co TCPP/MAA, Fe TCPP/MAA and Fe TPFPP/MAA were prepared using a method of gelation and calcination.3. To investigate a special bond between MAA support and metalloporphy-rins, the supported solid catalysts were characterized by Ultraviolet visible spec-troscopy(UV-Vis), Fourier transform infrared spectroscopy(FT-IR), X-ray pow-der diffraction(XRD), Thermogravimetric analysis(TG), Transmission electron microscopy(TEM), Field emission scanning electron microscopy (FESEM) and Electron paramagnetic resonance(EPR) techniques and so on.4. On the basis of the our previous experiences in catalytic oxidation of cyclohexane to K/A oil with air in absence of any solvent and no photochemical or electrochemical techniques, Co TCPP/MAA, Fe TCPP/MAA and Fe TPFPP/MAA were respectively investigated for catalysis for the oxidation. Effects of various parameters, such as oxidation temperature, air pressure, amount of metalloporphyrin and reaction time on this cyclohexane oxidation were explored. A reusability of the supported catalysts for the oxidation was compared with the corresponding unsupported metalloporphyrins under the appropriate catalytic conditions, respectively. Finally, the differences of catalytic activity among three types of supported catalysts were also researched.5. The experimental results show that a quantity of supported catalysts (containing only1.0or1.5mg of metalloporphyrins) can be consecutively used for11times, The catalytic efficiency of the supported catalyst is11times higher than those of corresponding unsupported metalloporphyrins. The active order for the aerobic oxidation of cyclohexane over the supported catalysts was Fe TPFPP/MAA>Co TCPP/MAA>Fe TCPP/MAA. The results indicates that the iron porphyrin with20F atoms on four benzene rings shown the best catalytic activity.6. Referring the literatures at home and abroad and according to the comparison of the experimental data, the hypothetic mechanism for the aerobic oxidation of cyclohexane catalyzed by those supported catalysts might be a free radical reaction.