TY - JOUR
T1 - Synthesis, characterization and catalytic activity of actinide Th-MCM-41 and U-MCM-41 hexagonal packed mesoporous molecular sieves
AU - Tismaneanu, Rodica
AU - Ray, Biswajit
AU - Khalfin, Rafael
AU - Semiat, Rafi
AU - Eisen, Moris S.
N1 - Funding Information:
This research was supported by the Ministry of Science, Government of Israel, by the Henri Gutwirth Fund for the Promotion of Research, by the Fund for the Promotion of Research at the Technion, by the Technion Water Research Institute for Instrumentation Grant and by the Technion V.P.R. fund. B.R. and R.T. thank the Ministry of Science for post-doctoral fellowships.
PY - 2001/6/12
Y1 - 2001/6/12
N2 - The synthesis and characterization of Th-MCM-41 and U-MCM-41 new members of a growing family of hexagonal packed metallo-silicates molecular sieves are described. The synthesis of these materials was achieved by a "liquid crystal templating" mechanism (LCT), with a C16 length chain for the cationic amine surfactant, when the additional metal salt was added to the synthesis mixture, forming large agglomerates imbedded within the silica matrix. For uranium, the synthesis was performed using UO2(NO3)2-6H2O as a precursor whereas for the thorium, the reaction was carried out using Th(NO3)4-5H2O (thorium nitrate pentahydrate) as the metal source. The incorporation of the uranium into the mesoporous material was performed via a complementary basic synthesis, whereas for the latter thorium, an acidic route was utilized. The Th-MCM-41 and U-MCM-41 were characterized by small angle X-ray scattering (SAXS), specific surface areas (Brunauer-Emmett-Teller (BET)), scanning electron microscopy (SEM) equipped with an energy dispersive spectrometer and X-ray photon spectroscopy (XPS). SAXS study revealed the mass fractal scattering characteristics of these materials with fractal dimension in the range of 2.78-2.95 Å. These materials also exhibited a hexagonal array of cylindrical mesopores from 27 to 30 Å in size, surface areas of over 850m2/g, and high thermal and hydrothermal stability. The incorporation of actinide metals into the MCM-41 matrixes was 3.23 (2) at.% of Th and 11.22 at.% for U, respectively. SEM study revealed the particle morphologies with large monolithic aggregates whereas XPS indicates the geometric configuration and coordination of the metal in the silicate. We have found that in U-MCM-41, most of the uranium metal in encounter in an octahedral geometry arrangement whereas in the Th-MCM-41, the corresponding thorium metal is assemble in tetrahedral environment In addition, the catalytic reactivity of these materials was measured for the hydroxylation of phenol and the alkylation of 2,4-di-tert-butylphenol with cinnamyl alcohol.
AB - The synthesis and characterization of Th-MCM-41 and U-MCM-41 new members of a growing family of hexagonal packed metallo-silicates molecular sieves are described. The synthesis of these materials was achieved by a "liquid crystal templating" mechanism (LCT), with a C16 length chain for the cationic amine surfactant, when the additional metal salt was added to the synthesis mixture, forming large agglomerates imbedded within the silica matrix. For uranium, the synthesis was performed using UO2(NO3)2-6H2O as a precursor whereas for the thorium, the reaction was carried out using Th(NO3)4-5H2O (thorium nitrate pentahydrate) as the metal source. The incorporation of the uranium into the mesoporous material was performed via a complementary basic synthesis, whereas for the latter thorium, an acidic route was utilized. The Th-MCM-41 and U-MCM-41 were characterized by small angle X-ray scattering (SAXS), specific surface areas (Brunauer-Emmett-Teller (BET)), scanning electron microscopy (SEM) equipped with an energy dispersive spectrometer and X-ray photon spectroscopy (XPS). SAXS study revealed the mass fractal scattering characteristics of these materials with fractal dimension in the range of 2.78-2.95 Å. These materials also exhibited a hexagonal array of cylindrical mesopores from 27 to 30 Å in size, surface areas of over 850m2/g, and high thermal and hydrothermal stability. The incorporation of actinide metals into the MCM-41 matrixes was 3.23 (2) at.% of Th and 11.22 at.% for U, respectively. SEM study revealed the particle morphologies with large monolithic aggregates whereas XPS indicates the geometric configuration and coordination of the metal in the silicate. We have found that in U-MCM-41, most of the uranium metal in encounter in an octahedral geometry arrangement whereas in the Th-MCM-41, the corresponding thorium metal is assemble in tetrahedral environment In addition, the catalytic reactivity of these materials was measured for the hydroxylation of phenol and the alkylation of 2,4-di-tert-butylphenol with cinnamyl alcohol.
KW - Alkylation
KW - Catalysis
KW - Hydroxylation
KW - Liquid crystal templating
KW - Mesoporous materials
KW - Th-MCM-41
KW - U-MCM-41
UR - http://www.scopus.com/inward/record.url?scp=0035849455&partnerID=8YFLogxK
U2 - 10.1016/S1381-1169(01)00109-1
DO - 10.1016/S1381-1169(01)00109-1
M3 - 文章
AN - SCOPUS:0035849455
SN - 1381-1169
VL - 171
SP - 229
EP - 241
JO - Journal of Molecular Catalysis A: Chemical
JF - Journal of Molecular Catalysis A: Chemical
IS - 1-2
ER -