AST

AST

AlPO4-16

Al(50), P(50)

Contributed by Joël Patarin

Verified by J. Shi and K. Balkus, by D. Akporiaye, and by T. Blasco

Type Material (Al₁₀P₁₀O₁₀)Q₂.₀F_1..₆: 3.0 H₂O ^a (Q= quinucidine)

Method C. Schott-Darie, J. Patarin, P. Y. Le Goff, H. Kessler and E. Benazzi [1]

Batch Composition 1 P₂O₅ : 1 Al₂O₃ : 1 Q : 1 HF : 60 H₂O

Source Materials

distilled water
phosphoric acid (Fluka, 85% H₃PO₄)
aluminum isopropoxide (Aldrich, 98%)
quinuclidine C₇H₁₃N (Fluka, 97%)
hydrofluoric acid (Prolabo, 40%)

Batch Preparationb (for 1.5 g of as-synthesized product)

(1) [4.00 g water + 2.31 g phosphoric acid + 4.17 g aluminum isopropoxide], stir until homogenized
(2) [6.15 g water + 1.14 g quinucidine], stir until dissolved
(3) [(1) + (2) + 0.50 g hydrofluoric acid], stir for 2 minutes. Gel pH= 7 to 7.5

Crystallization

Vessel: Teflon-lined stainless steel autoclave (50 cm³)
Temperature: 150âC
Tine: 24 hours
Agitation: none
Final pH: approximately 8

Product Recovery

(1) Dilute the reaction mixture with distilled water
(2) Filter or centrifuge
(3) Wash until the pH of the filtrate is 5.5 to 6
(4) Dry at 60-70⁰C overnight
(5) Yield: 50% based on aluminum (as-synthesized product containing quinudidine and some water) ^d

Product Characterization

XRD: AST (only crystalline phase), Space group 14, a₀= 9.3423(1) Å c₀= 13.4760(2) Å ^e
Elemental Analysis (wt%): Al₂O₃ = 32.8, P₂O₅ = 44.8, F = 1.9, (C₇H₁₃)N = 15.4, H₂O = 3.4
Crystal Size and Habit: tetrahedra, 0.5 to 3 um
Click here to view XRD pattern

References

[1] C. Schott-Darie, J. Patarin, P. Y. Le Goff, H. Kessler, E. Benazzi, Micropor. Mater. 3 (1994) 123
[2] J. M. Bennett, R. M. Kirchner, Zeolites 11(1991) 502

Notes

a. The Q/F molar ratio is lower than 1. Part of the quinucidine is either not protonated or OH^- groups are present in order to get a neutral material.

b. The starting mixture is prepared in a polyethylene vessel.

c. The reaction is exothermic.

d. Alter calcination (removal of the organic and fluoride species) the cubic form [2] of AlPO₄-16 is obtained.

e. According to reference [1].