Study On Preparation And Catalytic Properties Of Multicomponent Metal Oxides Porous Materials By Biotemplates

Turpentine is a cheap, renewable natural essential oil and its main component α-pinene is an important raw material in terpene chemistry, such as using for the production of spices, flavoring agents, drugs, pesticides, et al. α-pinene contains special double bond, which provides favorable conditions for the molecular structure modification and transfrom of chemical properties. The oxidation reaction of α-pinene can synthesize high value-added compounds, which is an important way of α-pinene deep processing applications. Therefore, according to the structure characteristics of α-pinene to develop a kind of green and high effective catalytic material is one of the research focuses in the field of catalysis application. Metal oxide catalysts show good activites at low temperature, which are favored by researchers.Owing to layer board cation of hydrotalcite-like compounds (HTLcs) can be adjustable and calcined decomposition within a certain temperature range, which is an important way of simple and rapid preparation of a series of composite metal oxides with different composition and high heat stability. At present, the preparation technology of natural biological materials as templates has gradually been developed, the synthetic materials can copy the original morphologies of the templates, that expands the diversity of metal oxide structures.In this dissertation, a series of porous composite metal oxides materials were successfully prepared by the combination of biological template method and the traditional co-precipitation method. The morphologies, structures and chemical compositions of the as-prepared samples were characterized by XRD、FT-IR、EDX、SEM、XPS and N2 adsorption and desorption analysis, and their catalytic properties of α-pinene oxidation reaction were investigated using H2O2 as oxidant.The porous material of ZnAlCe composite oxide (RP-ZnAlCe-LDO) was prepared by a simple and mild technology based on microwave-crystallization through in situ growth and calcination using rape pollen as biological template and ZnAlCe-HTLcs crystal solution as precursor. The results show that the synthesized RP-ZnAlCe-LDO can copy micro and nano structure of the rape pollen surface and form hierarchical holes with the pore size within 2～150 nm, between mesoporous and macroporous, and the specific surface area of 112.94 m2/g. Moreover, RP-ZnAlCe-LDO has good crystallinity and crystal structure. Then, RP-ZnAlCe-LDO was applied to catalyze α-pinene oxidation using 30%(w) H2O2 as oxidant. It is showed that the α-pinene conversion rate reaches 64.49%, and the selectivity of 2,3-epoxypinane, verbenol, verbenone is 41.52%,23.07% and 26.95%, respectively, under the α-pinene/H2O2 molar ratio of 1:1 using 15.0 mg RP-ZnAlCe-LDO as catalyst being dissolved in 2 mL ethyl acetate/H2O (volume ratio was 4:1) at 30℃ for 6 h.A series of porous double metal composite oxides were prepared based on co-precipitation, ageing and calcination, using potato starch as biotemplate. The influence of calcination temperature on the structure of oxides was investigated. The results indicate that the starch plays an embedded template during the formation of composite oxides, and the prepared samples have a particular morphology, good crystallinity, high heat stability, abundant distributions of mesoporous (2-5 nm pore size) and macroporous, and BET surface area of 767.36 m2/g. The prepared samples have good catalytic activity and high selectivity for the oxidation in the H2O2-α-pinene oxidation reaction.The porous MgZnAlFe quaternary composite of metal oxide (PS-MgZnAlFe-LDO) was prepared by starch template method. The catalytic material PS-MgZnAlFe-LDO had a high BET surface area (760.90 m2/g). The results show that the porous material of PS-MgZnAlFe-LDO has good catalytic effect on H2O2-a-pinene oxidation reaction. The conversion rate of α-pinene could reach 65.21%, and the selectivities of 2,3-epoxypinane, verbenol, verbenone are 65.87%、19.09%、12.23%, respectively, under the optimal conditions of 6.0 mg porous PS-MgZnAlFe-LDO as the catalyst, a-pinene/H2O2 molar ratio of 1:1.2 in 2 mL DMF/H2O (volume ratio was 4:1) at 20℃ for 8 h. Moreover, the conversion rate of α-pinene still could reach 47.01% when PS-MgZnAlFe-LDO was recycled five times.