MFI

MFI

Silicalite-1

Si(100)

Contributed by A. C. Faust and C. Schott-Darie

Verified by J. Cejka and by B. Schoeman

Type Material Si₉₆O₁₉₂F₄(TPA)₄(TPA = tetra-n-propylammonium)

Method J.-L Guth, H. Kessler, R. Wey [1]

Batch Composition 1 SiO₂: 0.08 (TPA)Br: 0.04 NH₄F: 20 H₂O

Source Materials

distilled water
tetrapropylammonium bromide (Fluka, 98%)
ammonium fluoride (Fluka, 98%)
silica (Degussa Aerosil 130, 99+%)

Batch Preparation (for 12 g product)

(1) [72 g water + 4.26 g tetrapropylammonium bromide + 0.296 g ammonium fluoride], stir until dissolved
(2) [(1) + 12 g silica], mix with a spatula, and then stir until homogenized. Initial pH = 6

Crystallization

Vessel: PTFE-lined autoclave
Time: 15 days ^a
Temperature: 200⁰C
Agitation: none

Product Recovery

(1) Filter, wash with distilled water
(2) Dry at 80⁰C
(3) Yield: 12.7 g; near 100% based on silica

Product Characterization

XRD: characteristic strong reflections at d = 11.01, 3.829, 3.806 and 3.698 Å
Elemental Analyses: Si₉₆O₁₉₂F₄(TPA)₄Crystal Size and Habit: prisms 95 x 80 um
Click here to view XRD pattern

Reference

[1] J.-L Guth, H. Kessler, R Wey, in Stud. Surf. Sci. Catal., Vol. 28, Y. Murakami, A. Iijima, J. W. Ward (eds.), Kodansha-Elsevier, Tokyo, 1986, p. 121

Note

a. Increasing NH₄F leads to a decrease in crystallization time (2 days for NH₄F/SiO₂= 1).