NMR investigation of substituted aluminophosphate AEL, ATS, ATN, AFS, AFY and GIS molecular sieves

D B Akolekar, Russell Francis Howe

Research output: Contribution to journalArticle

30 Citations (Scopus)

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 languageEnglish
Pages (from-to)3263-3268
Number of pages6
JournalJournal of the Chemical Society, Faraday Transactions
Volume93
Issue number17
Publication statusPublished - 7 Sep 1997

Keywords

  • nuclear magnetic-resonance
  • solid-state NMR
  • magnesium aluminophosphate
  • catalytic properties
  • thermal-stability
  • framework
  • acidity
  • AL-27
  • crystalline
  • ALPO4-21

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