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MTW |
ZSM-12 |
Si(97), Al(3) |
Contributed by Girolamo Giordano
Verified by Nguyen Huu Phu, by A. Souza de Araujo, and by G. Kuhl
Type Material Na0.5(MTEA)1.3[Al0.8Si27.2O56] : 0.6 H2O (MTEA = methyltriethylammonium)
Method S. Ernst, P. A. Jacobs, J. A. Martens, J. Weitkamp [1], P. Chu, G. H. KuhI [2]
Batch Composition 10 Na2O : Al2O3:100 SiO2 :2000 H2O: 2O MTEABr
Source Materials
distilled water
sodium hydroxide (Carlo Erba RPF, 99+% NaOH)
aluminum hydroxide hydrate [Al(OH)3] (Aldrich)
methyltriethylammonium bromide [MTEA Br] (Fluka)
precipitated silica (BDH, 99+% SiO2)
Batch Preparation (for ~2.5 g product)
(1) [9 g distilled water + 0.4 g sodium hydroxide + 0.078 g aluminum hydroxide hydrate], stir until dissolved
(2) [9 g distilled water + 1.96 g MTEA Br], stir until dissolved
(3) [(1)+ (2)], stir until homogenized
(4) [(3) + 3 g precipitated silica], stir for 1 hour at room temperature and seal in the reactor
Crystallization
Vessel: Teflon-lined autoclave, 20 mL
Time: 6 days
Temperature: 140¡C
Agitation: none
Product Recovery
(1) Cool to room temperature and filter to recover solids
(2) Wash with distilled water until filtrate pH = 9
(3) Dry at l050C
Product Characterization
XRD: MTW only crystalline phase; competing phases: MFI (high alumina), cristobalite (high temperature or high pH)
Elemental Analyses: 0.66 Na2O : Al2O3: 66.7 SiO2: l.5 H2O: 1.58 (MTEA)2O
Crystal Size and Habit: rice-grain shaped, length 5 um
Click here to view XRD pattern
References
[1] S. Ernst, P. A. Jacobs, J. A. Martens, J. Weitkamp, Zeolites 7 (1987) 458
[2] P. Chu, G. H. Kuhl, US Patent 4452 769 (1983)
[3] A. Katovic, G. Giordano, Chem. Express 6 (1991) 969
Note
a. MTW zeolite can also be obtained when tetraethylammonium bromide (TEA Br) substitutes for MTEA Br in the hydrogel described in the Batch Composition section. In this case spheroidal crystals of about 0.6 um diameter are obtained. [3]