Characterization and catalytic performances of three-dimensional mesoporous FeSBA-1 catalysts.
Iron substituted cubic cage type mesoporous molecular sieves (FeSBA-1) were synthesized for the first time in a highly acidic media using cetyltriethylammonium bromide as a template. The amount of Fe incorporation in SBA-1 can easily be controlled by the simple adjustment of the molar hydrochloric acid-to-silicon ratio. All the materials were unambiguously characterized by AAS, XRD, N2 adsorption, UV-Vis DRS, XPS, and ESR spectroscopy. The results from AAS, XRD, and N2 adsorption reveal that the iron atom can be incorporated in the framework of SBA-1 matrix without altering the structural order and the textural parameters. The nature and the coordination of iron atoms were extensively studied by XPS spectroscopy, and the results revealed that most of the iron atoms in FeSBA-1 are in +3 coordination state. UV-Vis DRS and ESR studies confirmed that the majority of the Fe atoms in FeSBA-1 exist in a tetrahedral coordination environment (most probably occupying framework positions). tert-Butylation of phenol employing tert-butanol as the alkylation agent was carried out over FeSBA-1 catalysts with different iron content and the results are compared with one-dimensional mesoporous catalysts. The influence of various reaction parameters such as reaction temperature, reactant feed ratio, weight hourly space velocity, and time-on-stream affecting the activity and selectivity of FeSBA-1 were also studied. Under the optimized reaction conditions, the FeSBA-1(36) catalyst showed superior catalytic performance for the tert-butylation of phenol as compared to the uni-dimensional mesoporous catalysts.
Vinu
Ajayan
A
Nano-ionics Materials Group and Advanced Electron Microscopy Group, National Institute for Materials Science, 1-1, Namiki, Tsukuba, 305-0044, Japan. vinu.ajayan@nims.go.jp
Krithiga
Thangavelu
T
Balasubramanian
Veerappan Vaithilingam
VV
Asthana
Anjana
A
Srinivasu
Pavuluri
P
Mori
Toshiyuki
T
Ariga
Katsuhiko
K
Ramanath
Ganapathiraman
G
Ganesan
Pethuraja Gopal
PG
D002384:Catalysis; D004578:Electron Spin Resonance Spectroscopy; D058085:Iron Compounds / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D014961:X-Ray Diffraction
D058085:Iron Compounds