Synthesis of Aluminosilicate and Gallosilicate Zeolites via a Charge Density Mismatch Approach and Their Characterization
SCIE
SCOPUS
- Title
- Synthesis of Aluminosilicate and Gallosilicate Zeolites via a Charge Density Mismatch Approach and Their Characterization
- Authors
- Park, MB; Cho, SJ; Hong, SB
- Date Issued
- 2011-02-16
- Publisher
- AMER CHEMICAL SOC
- Abstract
- Aluminosilicate and gallosilicate zeolite syntheses via a charge density mismatch (CDM) approach are compared at intermediate-silica compositions (Si/Me = 5-16, where Me is Al or Ga). With a variation of the crystallization temperature and of the type and/or concentration of alkali metal ions added as a crystallization structure-directing agent (SDA) to tetraethylammonium tetraethylammonium-tetraethylammonium-hexamethonium, and strontium-choline mixed-SDA systems, we were able to obtain 11 different zeolite structures. However, only 5 out of a total 40 pairs of aluminosilicate and gallosilicate synthesis runs at otherwise identical chemical compositions were found to give the same zeolite product with no detectable impurities, suggesting that the structure-directing ability of Ga is quite different from that of Al even in intermediate-silica synthesis conditions. The CDM approach to offretite synthesis led to hexagonal plate-like crystals with aspect ratios lower than 0.3, and UZM-22 exhibited no significant preference of Al substitution for particular tetrahedral sites, especially for site T1, unlike its framework type material ZSM-18. More interestingly, the EU-1 zeolite obtained from an aluminosilicate synthesis mixture containing Li+ as an inorganic crystallization SDA in the tetraethylammonium hexamethonium double-organic additive system has been characterized to locate about half of its Li+ ions in the framework, while the Li distribution over the 10 topologically different tetrahedral sites is nonrandom in nature.
- Keywords
- HIGH-SILICA ZEOLITES; POWDER DIFFRACTION; HYDROGEN-BONDS; STRUCTURAL-CHARACTERIZATION; MICROPOROUS LITHOSILICATE; CRYSTAL-STRUCTURES; ETHYLENE-GLYCOL; SI/AL RATIO; FRAMEWORK; NMR
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/17502
- DOI
- 10.1021/JA1095057
- ISSN
- 0002-7863
- Article Type
- Article
- Citation
- JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, vol. 133, no. 6, page. 1917 - 1934, 2011-02-16
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