The synthesis of large crystals of zeolite Y re-visited
The major synthesis routes described in the literature so far for zeolite Y (FAU) with an elevated n Si/ n Al-ratio and larger crystallite sizes were systematically re-investigated. Syntheses in the presence of triethanolamine with or without added bis(2-hydroxyethyl)dimethylammonium chloride yielde...
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| Published in: | Microporous and mesoporous materials Vol. 83; no. 1; pp. 333 - 344 |
|---|---|
| Main Authors: | , , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
Amsterdam
Elsevier Inc
01.09.2005
Elsevier |
| Subjects: | |
| ISSN: | 1387-1811, 1873-3093 |
| Online Access: | Get full text |
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| Summary: | The major synthesis routes described in the literature so far for zeolite Y (FAU) with an elevated
n
Si/
n
Al-ratio and larger crystallite sizes were systematically re-investigated. Syntheses in the presence of triethanolamine with or without added bis(2-hydroxyethyl)dimethylammonium chloride yielded large crystals (10–100
μm) of faujasite-type zeolites. However, only products with low
n
Si/
n
Al-ratios below 1.8 were obtained, and zeolite P was an inevitable side product or even the main product. Furthermore, the outcome of these syntheses was poorly reproducible. Following another known literature procedure, phase-pure zeolite Y could be obtained with the cyclic polyether 15-crown-5 as a structure-directing agent. The influence of ageing, homogenization and seeding of the synthesis gel, the crystallization time and temperature, different Si- and Al-sources and the addition of NaF as a mineralizer or of co-templates such as triethanolamine, ethylene glycol or 1,3,5-trioxane on the resulting product was investigated. A carefully optimized procedure led to large crystals of highly phase-pure zeolite Y with well defined octahedral morphology and a narrow crystal size distribution in the range of 4–5
μm. Such crystals can be reproducibly synthesized in high yields with an
n
Si/
n
Al-ratio of 3.4–4.0. Neither crystallization seeds nor an ageing of the synthesis gel before hydrothermal crystallization are required. |
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| ISSN: | 1387-1811 1873-3093 |
| DOI: | 10.1016/j.micromeso.2005.04.009 |