Synthesis Of Mesoporous Zirconium Phosphate And Its Performance For Catalytic Oxidation

Mesoporous phosphates show good application prospect as selective oxidation catalysts, especially for the reactions of larger substrates of molecule for their larger channels. In some previous works, mesoporous nickel phosphate (NiPOs), iron phosphate (FePO) and magnesium phosphate (MgPO) were found to be efficient catalysts in the selective oxidation of larger cycloolefins. In the present work, metal elements (Li, Cu, Mg, Ni, Zn) and Si were introduced into the structure of mesoporous FePO in synthesis and the catalytical performance of the resulting materials were evaluated in the probing cyclohexene epoxidation. Mesoporous ZrPO samples were synthesized by self-assembly method. The effect of synthesis condition, raw material ratio and processing temperature to the structure and catalytic performance of mesoporous ZrPO were studied. Its catalytic performance in the selective oxidationsof large reactants were studied, in comparison to those of mesoporous NiPOs, FePO and MgPO. The results are as fllows:1) The introduction of Li, Ni and Mg into mesoporous FePO had no substantial effects on the catalytic performance of the materials. However, the conversion of cyclohexene and selectivity of epoxidation path on mesoporous Cu-FePO and Zn-FePO decreased distinctly in the cyclohexene epoxidation reaction. Also, the catalyst was more apt to be hydrolyzed in the reaction. In comparison to mesoporous FePO. With the increaseing Si introduction amount, Si-FePO gave sharply weakened diffraction peak intensity, gradually lowered cyclohexene conversion and selectivity for cyclohexene oxide with increased selectivity for cyclohexanediol.2) Mesoporous ZrPO of layered symmetry was synthesized by self-assembly of inorganic zirconium, phosphorus source and surfactant. The Mesoporous ZrPO synthesized at 11O℃ and 3.8 of alkalinity, with raw material ratio of 0.8CTAB:0.6Zr(NO3)4:1.0H3PO4:220H2O had higher framework condensation. Its cyclohexene conversion and cyclohexene oxide selectivity were 39.54%and 95.53%, respectively. Its performance in cyclohexene conversion weakened with rising treating temperature, and a sample of best performance was obtained at a treating temperatureof 100℃.3) With references of NiPO-2, FePO and MgPO, we studied the catalytic performance of mesoporous ZrPO in the epoxidation of different sized cycloolefin. In a reaction system of 25 ml stress reaction tube, mesoporous ZrPO showed a good catalytic properties in the epoxidation of cycloolefins with higher catalytic activity and higher selectivity for the target products in the reaction of different sized substrates, when compared with the references. In the reaction system suing 50 ml three mouth flask, the catalytic activities of the four catalysts rose to different extents, and the highest rise was obtained on mesoporous ZrPO, which showed the yields of target cyclohexene oxide, cyclooctene oxide and cyclododecene oxide as high as 61.97%,74.29%and 71.54%, respectively.