SUBSTITUTION OF AL IN THE ALPO4-5 AND ALPO4-11 FRAMEWORKS BY SI AND FE - A STUDY BY MOSSBAUER, MAGIC-ANGLE-SPINNING NUCLEAR-MAGNETIC-RESONANCE AND ELECTRON-PARAMAGNETIC RESONANCE SPECTROSCOPIES AND CHEMICAL PROBES
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Title |
SUBSTITUTION OF AL IN THE ALPO4-5 AND ALPO4-11 FRAMEWORKS BY SI AND FE - A STUDY BY MOSSBAUER, MAGIC-ANGLE-SPINNING NUCLEAR-MAGNETIC-RESONANCE AND ELECTRON-PARAMAGNETIC RESONANCE SPECTROSCOPIES AND CHEMICAL PROBES
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Creator |
DAS, J
SATYANARYANA, CVV CHAKRABARTY, DK PIRAMANAYAGAM, SN SHRINGI, SN |
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Subject |
crystalline inorganic solids
silicoaluminophosphate molecular-sieves nmr sapo-5 zeolites al-27 p-31 |
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Description |
Substitution of Al by Fe and Si in the AlPO4-5 and AIPO4-11 frameworks has been investigated by a number of experimental methods such as electron paramagnetic resonance (EPR), Mossbauer and magic-angle-spinning nuclear magnetic resonance (MASNMR) spectroscopies and temperature-programmed desorption of ammonia. There are indications that Fe(III) replaces Al(III) and the extent of substitution increases with time of reaction. The FAPO-n formed, however, is contaminated with an amorphous phase containing Fe(III). Silicon replaces phosphorus in the framework only to a limited extent and in those cases when the synthesis gel had a higher amount of silicon, the product was contaminated with an amorphous silica-containing phase. No evidence tor silicon removing a phosphorus-aluminium pair has been found. The conclusions are also supported by the results of acidity measurements and the alkylation of toluene with methanol on these molecular sieve samples.
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Publisher |
ROYAL SOC CHEMISTRY
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Date |
2011-08-28T19:23:38Z
2011-12-26T12:58:11Z 2011-12-27T05:47:41Z 2011-08-28T19:23:38Z 2011-12-26T12:58:11Z 2011-12-27T05:47:41Z 1992 |
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Type |
Article
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Identifier |
JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS, 88(21), 3255-3261
0956-5000 http://dx.doi.org/10.1039/ft9928803255 http://dspace.library.iitb.ac.in/xmlui/handle/10054/11825 http://hdl.handle.net/10054/11825 |
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Language |
en
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