The reversible transition of the molecular sieve VPI-5 into ALPO sub 4 sup minus 8

Journal Article · Wed Aug 01 04:00:00 EDT 1990 · Journal of Solid State Chemistry; (USA)

DOI:https://doi.org/10.1016/0022-4596(90)90052-Y· OSTI ID:6444321

Vogt, E T.C. ^[1]; Richardson, Jr, J W ^[2]

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1. Akzo Chemicals bv, Amsterdam (Netherlands)
2. Univ. of Chicago, IL (USA) Argonne National Lab., IL (USA)

In this letter the authors describe the reversibility of the recrystallization of the aluminophosphate molecular sieve VPI-5 to ALPO{sub 4}{sup {minus}8}, and the structure of ALPO{sub 4}{sup {minus}8}. VPI-5 is known to contain one-dimensional circular pores circumscribed by 18 tetrahedral atoms. Upon heating in the presence of moisture it is known to recrystallize to ALPO{sub 4}{sup {minus}8}. This transition now proves to be reversible. Although phase transitions of aluminophosphate molecular sieves have been described, this is the first report of such a transition being reversible. ALPO{sub 4}{sup {minus}8} is found to contain one-dimensional elliptical pores, with free diameters of 7.5 to 9.5 {angstrom} circumscribed by 14 tetrahedral atoms. This new pore system thus contains one of the largest openings described so far, second only to VPI-5.

• OSTI ID: 6444321
• Journal Information: Journal of Solid State Chemistry; (USA), Journal Name: Journal of Solid State Chemistry; (USA) Vol. 87:2; ISSN 0022-4596; ISSN JSSCB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
ADSORBENTS
ALUMINIUM COMPOUNDS
ALUMINIUM PHOSPHATES
CRYSTAL STRUCTURE
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
MATERIALS
MEASURING METHODS
MICROSTRUCTURE
MINERALS
MOLECULAR SIEVES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHOSPHATES
PHOSPHORUS COMPOUNDS
RECRYSTALLIZATION
ZEOLITES