摘要
The mesoporous Al-SBA-15 zeolite was obtained via impregnation of pure silica-based SBA-15 zeolite with aluminum nitrate.The Al-SBA-15 sample was calcined in air at 800 ℃ for 6 h and hydrothermally treated at near 100 ℃ for 120 h,respectively,and then the thermal and hydrothermal stability of Al-SBA-15 sample was investigated by X-ray diffractometry (XRD),scanning electron microscopy (SEM),transmission electron microscopy (TEM) and nitrogen adsorption and desorption techniques.The Al-SBA-15 sample was also studied by 27 Al nuclear magnetic resonance (27 Al NMR) and ammonia temperature programmed desorption (NH 3-TPD) techniques.In addition,the catalytic activity of Al-SBA-15 zeolite was investigated by the Friedel-Crafts reactions of 2,4-di-tert-butylphenol with cinnamyl alcohol.The test results showed that the thermal and hydrothermal stability of Al-SBA-15 zeolite was better than that of SBA-15 zeo-lite.The Al-SBA-15 zeolite sample prepared by impregnation method exhibits more framework aluminum species and Al-O-Si units.Therefore,the number of the surface hydroxyl groups was reduced,resulting in the stabilization of framework structure ofAl-SBA-15 zeolite.The aluminum species can form weak and medium-strong acid sites with catalytic activity.
The mesoporous Al-SBA-15 zeolite was obtained via impregnation of pure silica-based SBA-15 zeolite with aluminum nitrate. The Al-SBA-15 sample was calcined in air at 800 ℃ for 6 h and hydrothermally treated at near 100 ℃ for 120 h, respectively, and then the thermal and hydrothermal stability of Al-SBA-15 sample was investigated by X- ray diffractometry （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and nitrogen adsorption and desorption techniques. The Al-SBA-15 sample was also studied by 27Al nuclear magnetic resonance （27Al NMR） and ammonia temperature programmed desorption （NH3-TPD） techniques. In addition, the catalytic activity of Al- SBA-15 zeolite was investigated by the Friedel-Crafts reactions of 2,4-di-tert-butylphenol with cinnamyl alcohol. The test results showed that the thermal and hydrothermal stability of Al-SBA-1 5 zeolite was better than that of SBA-1 5 zeolite. The Al-SBA-1 5 zeolite sample prepared by impregnation method exhibits more framework aluminum species and Al- O-Si units. Therefore, the number of the surface hydroxyl groups was reduced, resulting in the stabilization of framework structure of Al-SBA-15 zeolite. The aluminum species can form weak and medium-strong acid sites with catalytic activity.
