The Na2CO3-modified HZSM-5 zeolites were further treated by tetrapropylammonium hydroxide(TPAOH) solution. The effect of TPAOH concentration on the secondary crystallization process was investigated. The resulting sam...The Na2CO3-modified HZSM-5 zeolites were further treated by tetrapropylammonium hydroxide(TPAOH) solution. The effect of TPAOH concentration on the secondary crystallization process was investigated. The resulting samples were characterized by a complementary combination of X-ray diffraction, N2 adsorption/desorption, scanning electron microscopy, X-ray fluorescence spectroscopy, XPS, 27 Al and 29 Si magic-angle spinning nuclear magnetic resonance spectroscopy, BET and temperature-programmed desorption techniques. The results showed that the secondary crystallization of the HZSM-5 zeolite could result in migration of non-framework species from the internal channels to the zeolite surface and their transformation into framework species. The catalytic activity of these modified samples for thiophene alkylation was evaluated. Both the activity and stability of the catalysts were improved after secondary crystallization.展开更多
基金the financial support by the Natural Science Foundation of Liaoning Province of China (Grant No.201202126)the National Natural Science Foundation of China (Grant Nos. 21276253 and 21401093)
文摘The Na2CO3-modified HZSM-5 zeolites were further treated by tetrapropylammonium hydroxide(TPAOH) solution. The effect of TPAOH concentration on the secondary crystallization process was investigated. The resulting samples were characterized by a complementary combination of X-ray diffraction, N2 adsorption/desorption, scanning electron microscopy, X-ray fluorescence spectroscopy, XPS, 27 Al and 29 Si magic-angle spinning nuclear magnetic resonance spectroscopy, BET and temperature-programmed desorption techniques. The results showed that the secondary crystallization of the HZSM-5 zeolite could result in migration of non-framework species from the internal channels to the zeolite surface and their transformation into framework species. The catalytic activity of these modified samples for thiophene alkylation was evaluated. Both the activity and stability of the catalysts were improved after secondary crystallization.
