In this work, Al grafted SBA-16 (Al-SBA-16) is converted into a fully crystalline hierarchical mesoporous ZSM-5 zeolite with hydrothermal stability by steam assisted crystallization under controlled conditions. The secondary mesoporosity is due to reorganization and recrystallization events happening upon steaming the precursor. Two mesoporous aluminosilicates (Al-SBA-16s) are used as the precursors of zeolites. The precursors are obtained by post-synthetic Al grafting on the silica walls of SBA-16 with aluminium isopropoxide and sodium aluminate. Mesoporous ZSM-5 zeolites obtained from the Al-SBA-16 precursors and commercial ZSM-5 are characterized using XRD, XRF, FT-IR, TEM, N₂ adsorption, ²⁷Al and ²⁹Si MAS NMR, and TPD of NH₃. The results indicated the presence of intraparticle mesoporosity in the prepared mesoporous zeolites and they have comparable crystallinity with commercial ZSM-5. Catalytic activity of the synthesized mesoporous zeolites in benzylation of mesitylene is found to be comparatively more than commercial ZSM-5, which shows existence of micro/meso hierarchical structure in the mesoporous ZSM-5 zeolites. The aluminium sources, aluminium isopropoxide and sodium aluminate have a remarkable influence on the textural, acidity, and hydrothermal stability characteristics of the synthesized mesoporous ZSM-5 zeolites.

中文翻译：

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通过蒸汽辅助结晶从Al-SBA-16轻松合成水热稳定的介孔ZSM-5沸石

在这项工作中，通过在受控条件下进行蒸汽辅助结晶，将接枝的Al SBA-16（Al-SBA-16）转变为具有水热稳定性的全结晶分级介孔ZSM-5沸石。二次介孔性是由于汽化前体时发生的重组和重结晶事件。两种中孔铝硅酸盐（Al-SBA-16s）用作沸石的前体。前体是通过用异丙醇铝和铝酸钠在SBA-16的二氧化硅壁上进行后合成Al接枝而获得的。使用XRD，XRF，FT-IR，TEM，N ₂吸附，²⁷ Al和²⁹ Si MAS NMR和NH _3的TPD表征从Al-SBA-16前体和商业ZSM-5获得的中孔ZSM-5沸石。。结果表明在制备的中孔沸石中存在颗粒内中孔，并且它们具有与商业ZSM-5相当的结晶度。发现合成的介孔沸石在均二甲苯的苄基化中的催化活性比市售的ZSM-5相对更高，这表明在介孔的ZSM-5沸石中存在微/介观分级结构。铝源，异丙醇铝和铝酸钠对合成的中孔ZSM-5沸石的质地，酸度和水热稳定性能有显着影响。