Bridging Methoxy Groups in NaY, NaX and NaLSX Zeolites

Autor:	M. Dlouhá, S. Vratislav, V. Bosacek
Rok vydání:	2004
Předmět:	Sodium Neutron diffraction Inorganic chemistry chemistry.chemical_element General Chemistry Carbon-13 NMR Electronegativity chemistry.chemical_compound Crystallography chemistry Chemisorption Zeolite Group 2 organometallic chemistry Methyl iodide
Zdroj:	Collection of Czechoslovak Chemical Communications. 69:1537-1552
ISSN:	1212-6950 0010-0765
Popis:	Distribution of chemisorbed methyl groups and sodium cations in the structure of NaY, NaX and NaLSX zeolites was estimated by neutron diffraction. Chemisorbed methyl groups were prepared in the structure by reaction of methyl iodide with reactive sodium cations available in SII and SIII positions of faujasites. Methyl cations CH3+, formed in the reaction, react immediately with the lattice oxygen forming surface bonded methyl groups in bridging configuration. 13C NMR signals of chemisorbed surface species and their linear dependence on the intermediate electronegativity of the zeolite lie in the interval from 53 ppm for most basic CsLSX to 58 ppm TMS for stabilized and acid leached sample of H,NaY-St. Changes in the distribution of structural sodium cations in the lattice after chemisorption of methyl cations have been detected. C-O distances in surface methoxy groups in void cavities were longer than in ordinary crystalline organometallic compounds with bridging methoxy groups. The location of chemisorbed methyl groups at the O1 lattice oxygen type was most probable for NaY. Nuclear densities of chemisorbed methyl groups were detected in NaX at O1 and at O4 lattice oxygens. The origin of the split signal at 58 ppm on NaX and NaLSX samples has been discussed.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::77aa192705f3b4df89178c4973f10c2c https://doi.org/10.1135/cccc20041537 Zobrazit plný text záznamu