Synthesis And Catalytic Performance Of Zeolite Beta By Aerosol Assisted Hydrothermal Process

In this paper, the aerosol assisted hydrothermal process was conducted to synthesize zeolite Beta. The synthesis conditions were systematically studied. All samples obtained were characterized by XRD, SEM, XRF, N2 adsorption-desorption and NH3-TPD techniques. On this basis, catalytic performance of zeolite Beta synthesized by different methods were evaluated via the benzene/propylene alkylation.To find the optimized synthesis conditions of the aerosol assisted hydrothermal process, the amount of template, crystallization temperature and crystallization time were systematically studied by using the zeolite Beta with a SiO2/Al2O3 ratio of 50. The results show that the optimized synthesis conditions are TEAOH/SiO2 ratio=0.15, crystallization time =72 h, crystallization temperature=135℃. Compared with that synthesized by hydrothermal method, zeolite Beta synthesized by the aerosol assisted hydrothermal process can be conducted by using a relatively low amount of template, and the production of which was promoted as well.Moreover, zeolite Beta with different SiO2/Al2O3 ratios were synthesized under the optimized synthesis conditions. The results show that the sample with the SiO2/Al2O3 ratio of 30 shows lower relative crystallinity. The relative crystallinities of the samples increase with increasing the the SiO2/Al2O3 ratio. The final SiO2/Al2O3 ratios of all the samples arelower than the theoretical value, which means part of Si is lost during the synthesis.Besides, samples synthesized by aerosol assisted hydrothermal process and hydrothermal methods were evaluated via the benzene/propylene alkylation. The results show that aerosol assisted samples show higher activity and selectivity because of the higher specific surface area and bigger pore volume due to the micropores.The effects of the SiO2/Al2O3 ratio were also studied in this paper. For the zeolite Beta synthesized by aerosol assisted hydrothermal process, The activities of the samples increase with mopre due to the decrease the the SiO2/Al2O3 ratio.