Synthesis and characterization of divalent cobalt-substituted mesoporous aluminophosphate molecular sieves and their application as novel heterogeneous catalysts for the oxidation of cycloalkanes
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Title |
Synthesis and characterization of divalent cobalt-substituted mesoporous aluminophosphate molecular sieves and their application as novel heterogeneous catalysts for the oxidation of cycloalkanes
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Creator |
SELVAM, P
MOHAPATRA, SK |
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Subject |
liquid-phase oxidation
electron-spin-resonance selective oxidation cyclohexane oxidation redox centers mesostructured aluminophosphates hydrogen-peroxide adipic acid zeolite phosphate cobalt mesoporous aluminophosphates cohma oxidation cycloalkanes cyclohexane cyclooctane cyclododecane |
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Description |
Thermally stable divalent cobalt-substituted hexagonal mesoporous aluminophosphate, CoHMA molecular sieves were hydrothermally synthesized and systematically characterized by several analytical and spectroscopic techniques. XRD, TEM, ED, ICP-AES, TGA-DTA, N-2 sorption, DR-UV-vis, XANES, and NH3-TPD studies showed isomorphous substitution of divalent cobalt in a tetrahedral framework of a mesoporous aluminophosphate matrix. Furthermore, the blue color of CoHMA, before and after thermal treatment, further confirmed the tetrahedral environment of divalent cobalt in the matrix. As a result, the CoHMA catalyst showed excellent activity for the oxidation of cycloalkanes, that is, cyclohexane, cyclooctane and cyclododecane, under mild reaction conditions. Unlike the many other cobalt-based heterogeneous catalysts reported so far, CoHMA does not show any dislodgement or segregation of cobalt with calcination or any other postsynthesis treatments. In this study, the performance of CoHMA was also compared with the cobalt-containing microporous aluminophosphate, that is, CoAPO-5 with AFI topology, as well as with both microporous and mesoporous analogues of cobalt silicate molecular sieves that have MFI or MCM-41 structures. (c) 2005
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Publisher |
ACADEMIC PRESS INC ELSEVIER SCIENCE
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Date |
2011-07-12T17:10:13Z
2011-12-26T12:49:00Z 2011-12-27T05:34:34Z 2011-07-12T17:10:13Z 2011-12-26T12:49:00Z 2011-12-27T05:34:34Z 2005 |
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Type |
Article
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Identifier |
JOURNAL OF CATALYSIS, 233(2), 276-287
0021-9517 http://dx.doi.org/10.1016/j.jcat.2005.04.036 http://dspace.library.iitb.ac.in/xmlui/handle/10054/3393 http://hdl.handle.net/10054/3393 |
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Language |
en
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