Study On Synthesis, Characterization And Catalytic Behavior Of Novel Hetero-atom β Zeolite

Beta zeolite, possessing a three-dimensional large-pore 12-MR, has attracted peoples'interest in the green catalyst materials field because of its high silica, good thermal and hydrothermal stability. Beta zeolite will add some new physical, chemical prosperity and special catalytic performance when hetero-atom was introduced to the framework of the zeolite. Transition metal atoms can play good active central roles in the beta zeolite when the transition metal atoms are introduced to the framework of the beta zeolite especially. Beta zeolite has increasingly attracted attention as its more outstanding catalytic performance, therefore, studying novel hetero-atom zeolite has theoretical significance and practical application value.In this dissertation, Fe-V-βand Cu-βzeolites were successfully synthesized by using hydrothermal method, Cu-βzeolites has also been synthesized by using nucleation gel method. The factors that affect the synthesis ofβzeolite have been investigated. The catalytic behavior of heteroatom-βzeolite has also been explored. The main contents discussed were as follows:(1) Synthesis, Characterization and Catalytic Behavior of Bihetero-atom Fe-V-βZeoliteFe-V-βzeolite has been hydrothermally synthesized in a SiO2-Fe2O3-V2O5-(TEA)2O-H2O-NH4F system. The structure and chemical composition of the products were determined by X-ray diffraction, infrared spectroscopy, Thermogravimetry-Differential thermal analysis, Inductively coupled plasma-atomic emission spetrometry, Scanning electron microscope-Energy Dispersive Spectrometry and Ultraviolet-visual diffuse reflection spectroscopy. The factors that affect the synthesis of Fe-V-βzeolite have been investigated. The results indicate that the Fe-V-βzeolite can be synthesized from the original mixture with the mole ratio of n(SiO2): n(Fe2O3): n(V2O5): n(TEA)2O]: n(H2O): n(NH4F)= 60:(0.1～0.75):(0.1～0.75):(17～18):(550～650): (30～50), and the Fe and V atoms present in the framework of the zeolite. The as-synthesized Fe-V-βzeolite showed excellent catalytic activity in the reaction of oxidation of styrene using H2O2 as the oxidant. The percent conversion of styrene is 25.4%. The selectivity of the products is phCHO 69.1%, phCH2CHO 22.5% and phCOMe 4.1% respectively.(2) Synthesis, Characterization and Catalytic Behavior of Bihetero-atom Cu-βZeoliteCu-βzeolite has been hydrothermally synthesized in a SiO2-CuO-(TEA)2O-H2O-NH4F system. The structural characteristics of the products were determined by means of XRD, IR, TG/DTA, ICP, SEM and UV-Vis. The effects of various factors on the synthesis of Cu-βzeolite have been investigated. The results indicate that Cu-βzeolite can be synthesized from the original mixture with the mole ratio of n(SiO2): n(CuO): n(TEA)2O]: n(H2O):n(NH4F)= 60:(0.5～5.0):(16～18): (550～650):(25～50), Cu-βzeolite contain aβphase of good species, and the Cu atoms present in the framework of the zeolite. The catalytic behavior of Cu-βzeolite in oxidation of the hydroxylation of phenol using H2O2 as the oxidant has also been explored. The results have shown that Cu-βzeolite have high catalytic activity.(3) Studies on the synthesis of Cu-βZeolite by Using Nucleation GelCu-βzeolite has been synthesized by using nucleation gel method. The structural characteristics of the products were determined by means of XRD, FT-IR, UV-Vis, SEM and TG/DTA. Because organic template TEAOH was put only into nucleation gel and a small amount of nucleation gel was put only into reaction mixture of synthetic Cu-βzeolite, it has decreased significantly the cost of synthetic Cu-βzeolite.