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采用直接合成法制备Al-Z-SBA-15复合分子筛,以丙烯酸酯化反应为探针,X射线衍射表征为手段,考察ZSM-5的硅铝比、降解时间、硝酸铝引入量、晶化温度、晶化时间对复合分子筛的结构和酸性的影响。利用X射线衍射、Fourier变换红外光谱、N2吸附-脱附和吡啶红外光谱对Al-Z-SBA-15的理化性质进行了表征分析。结果表明:当ZSM-5中的Si/Al摩尔比为80、降解时间为24 h、正硅酸乙酯与硝酸铝的摩尔比为35、晶化温度为120℃、晶化时间为48 h时,Al-Z-SBA-15有序度最高,酸性最强;沸石结构单元以五元环的形式存在于骨架中,增加了孔壁厚度,大部分Al取代硅以稳定的骨架铝的形式嵌入到孔壁中,提高了孔壁的结晶度。与Z-SBA-15相比,Al-Z-SBA-15催化活性和水热稳定性显著提高。
Al-Z-SBA-15 composite molecular sieve was prepared by direct synthesis method. Acrylation reaction was used as a probe and characterized by X-ray diffraction. The effects of Si / Al ratio, degradation time, amount of aluminum nitrate introduced, Effect of temperature and crystallization time on the structure and acidity of composite zeolite. The physical and chemical properties of Al-Z-SBA-15 were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, N2 adsorption-desorption and pyridine-infrared spectroscopy. The results showed that when the mole ratio of Si / Al in ZSM-5 was 80, the degradation time was 24 h, the molar ratio of TEOS to aluminum nitrate was 35, the crystallization temperature was 120 ℃ and the crystallization time was 48 h Al-Z-SBA-15 has the highest degree of ordering and the strongest acidity. The zeolite structural unit exists in the framework as a five-membered ring, increasing the wall thickness. Most Al-substituted silicon is in the form of stable framework aluminum Embedded in the hole wall, increasing the crystallinity of the hole wall. Compared with Z-SBA-15, the catalytic activity and hydrothermal stability of Al-Z-SBA-15 are significantly improved.