TY - JOUR
T1 - Mesoporous aluminosilicates with ordered hexagonal structure, strong acidity, and extraordinary hydrothermal stability at high temperatures
AU - Zhang, Z.
AU - Han, Y.
AU - Xiao, F. S.
AU - Qiu, S.
AU - Zhu, L.
AU - Wang, R.
AU - Yu, Y.
AU - Zhang, Z.
AU - Zou, B.
AU - Wang, Y.
AU - Sun, H.
AU - Zhao, D.
AU - Wei, Y.
PY - 2001/10/9
Y1 - 2001/10/9
N2 - Highly ordered hexagonal mesoporous aluminosilicates (MAS-5) with uniform pore sizes have been successfully synthesized from assembly of preformed aluminosilcate precursors with cetyltrimethylammonium bromide (CTAB) surfactant. The aluminosilicate precursors were obtained by heating, at 100-140 °C for 2-10 h, aluminasilica gels at the Al2O3/SiO2/TEAOH/H2O molar ratios of 1.0/7.0-350/10.0-33.0/500-2000. Mesoporous MAS-5 shows extraordinary stability both in boiling water (over 300 h) and in steam (800 °C for 2 h). Temperature-programmed desorption of ammonia shows that the acidic strength of MAS-5 is much higher than that of MCM-41 and is comparable to that of microporous Beta zeolite. In catalytic cracking of 1,3,5-triisopropylbenzene and alkylation of isobutane with butene, MAS-5 exhibits greater catalytic activity and selectivity, as compared with MCM-41 and HZSM-5. The MAS-5 samples were characterized with infrared, UV-Raman, and NMR spectroscopy and numerous other techniques. The results suggest that MAS-5 consists of both mesopores and micropores and that the pore walls of MAS-5 contain primary and secondary structural building units, similar to those of microporous zeolites. Such unique structural features might be responsible for the observed strong acidity and high thermal stability of the mesoporous aluminosilicates with well-ordered hexagonal symmetry.
AB - Highly ordered hexagonal mesoporous aluminosilicates (MAS-5) with uniform pore sizes have been successfully synthesized from assembly of preformed aluminosilcate precursors with cetyltrimethylammonium bromide (CTAB) surfactant. The aluminosilicate precursors were obtained by heating, at 100-140 °C for 2-10 h, aluminasilica gels at the Al2O3/SiO2/TEAOH/H2O molar ratios of 1.0/7.0-350/10.0-33.0/500-2000. Mesoporous MAS-5 shows extraordinary stability both in boiling water (over 300 h) and in steam (800 °C for 2 h). Temperature-programmed desorption of ammonia shows that the acidic strength of MAS-5 is much higher than that of MCM-41 and is comparable to that of microporous Beta zeolite. In catalytic cracking of 1,3,5-triisopropylbenzene and alkylation of isobutane with butene, MAS-5 exhibits greater catalytic activity and selectivity, as compared with MCM-41 and HZSM-5. The MAS-5 samples were characterized with infrared, UV-Raman, and NMR spectroscopy and numerous other techniques. The results suggest that MAS-5 consists of both mesopores and micropores and that the pore walls of MAS-5 contain primary and secondary structural building units, similar to those of microporous zeolites. Such unique structural features might be responsible for the observed strong acidity and high thermal stability of the mesoporous aluminosilicates with well-ordered hexagonal symmetry.
UR - http://www.scopus.com/inward/record.url?scp=0034803437&partnerID=8YFLogxK
U2 - 10.1021/ja004138t
DO - 10.1021/ja004138t
M3 - Article
C2 - 11457329
AN - SCOPUS:0034803437
SN - 0002-7863
VL - 123
SP - 5014
EP - 5021
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 21
ER -