Abstract
The never metal-incorporated aluminophosphates MAPO-11, MAPO-36, MAPSO-36, CoAPO-36, ZAPO-36, MAPO-39, MAPO-43 and MAPO-50 have been prepared and studied by Al-27 and P-31 MAS NMR spectroscopy. Al-27 NMR spectra show a signal characteristic of tetrahedral Al in the range 30-45 ppm. MeAPOs (Me = metal) with higher metal loadings also show additional signals at lower chemical shift due to Al in higher coordination. P-31 NMR spectra show complex patterns of overlapping signals which can be assigned to P atoms having differing numbers of Al or metal atom next-nearest neighbours. The P/Al and P/Me ratios calculated from the relative intensities of these signals are in good agreement with the results of chemical analysis. The intensity ratios do not, however, follow a binomial distribution indicating non-random patterns of metal substitution in the AlPO frameworks. The effects of calcination of these materials are also described.
Original language | English |
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Pages (from-to) | 3263-3268 |
Number of pages | 6 |
Journal | Journal of the Chemical Society, Faraday Transactions |
Volume | 93 |
Issue number | 17 |
Publication status | Published - 7 Sept 1997 |
Keywords
- nuclear magnetic-resonance
- solid-state NMR
- magnesium aluminophosphate
- catalytic properties
- thermal-stability
- framework
- acidity
- AL-27
- crystalline
- ALPO4-21