SYNTHESIS, CRYSTAL STRUCTURE, CHARACTERIZATION, AND CATALYTIC PROPERTIES OF TNU-9
SCIE
SCOPUS
- Title
- SYNTHESIS, CRYSTAL STRUCTURE, CHARACTERIZATION, AND CATALYTIC PROPERTIES OF TNU-9
- Authors
- Hong, SB; Min, HK; Shin, CH; Cox, PA; Warrender, SJ; Wright, PA
- Date Issued
- 2007-09-05
- Publisher
- AMER CHEMICAL SOC
- Abstract
- The synthesis, crystal structure, characterization, and catalytic properties of the novel mediumpore zeolite TNU-9 (framework type TUN), one of the most crystallographically complex zeolites known to date, are described. TNU-9 was found to crystallize under hydrothermal conditions at the expense of a lamellar precursor over a very narrow range of SiO2/Al2O3 and NaOH/SiO2 ratios and in the presence of 1,4-bis(N-methylpyrrolidinium)butane and Na+ ions as structure-directing agents. A combination of molecular modeling and Rietveld refinement using synchrotron powder diffraction data confirms the proposed topology of as-made TNU-9 and suggests three or possibly four different sites for the organic within the complex pore structure. The proton form (H-TNU-9) of this new medium-pore zeolite exhibits exceptionally high hydrothermal stability, as well as very strong acidity. When compared to H-ZSM-5, H-MCM-22, H-mordenite, and H-Beta, H-TNU-9 displays unique shape selectivities for the acid-catalyzed reactions of monoaromatic hydrocarbons such as the disproportionation of toluene and the isomerization and disproportionation of m-xylene. In particular, for the isomerization of m-xylene, the ratio of isomerization to disproportionation increases steadily to values in excess of 50 with prolonged time on stream and a high p/o xylene ratio is observed in the products, achieving a value of ca. 6 after only a short time on stream. These results are rationalized on the basis of the unique pore topology of TNU-9.
- Keywords
- STRUCTURE-DIRECTING AGENTS; ZEOLITE MCM-22; SKELETAL ISOMERIZATION; POWDER DIFFRACTION; P-XYLENE; DISPROPORTIONATION; IONS; NMR; TOPOLOGY; TOLUENE
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/29431
- DOI
- 10.1021/ja073109g
- ISSN
- 0002-7863
- Article Type
- Article
- Citation
- JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, vol. 129, no. 35, page. 10870 - 10885, 2007-09-05
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