Bridging Methoxy Groups in NaY, NaX and NaLSX Zeolites

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Title:Bridging Methoxy Groups in NaY, NaX and NaLSX Zeolites
Creators:
Bosáček, Vladimír
Vratislav, Stanislav
Dlouhá, Mája
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 69, 8, pp. 1537-1552
Uncontrolled Keywords:Cations in faujasites, Zeolites, Chemisorbed methylium cations, <sup>13</sup>C MAS NMR spectroscopy, Neutron diffraction

Abstract

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 CH<sub>3</sub><sup>+</sup>, formed in the reaction, react immediately with the lattice oxygen forming surface bonded methyl groups in bridging configuration. <sup>13</sup>C 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 O<sub>1</sub> lattice oxygen type was most probable for NaY. Nuclear densities of chemisorbed methyl groups were detected in NaX at O<sub>1</sub> and at O<sub>4</sub> lattice oxygens. The origin of the split signal at 58 ppm on NaX and NaLSX samples has been discussed. <p>

Title:Bridging Methoxy Groups in NaY, NaX and NaLSX Zeolites
Creators:
Bosáček, Vladimír
Vratislav, Stanislav
Dlouhá, Mája
Uncontrolled Keywords:Cations in faujasites, Zeolites, Chemisorbed methylium cations, <sup>13</sup>C MAS NMR spectroscopy, Neutron diffraction
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:69
Number:8
Page Range:pp. 1537-1552
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc20041537UNSPECIFIED
ID Code:2292
Item Type:Article
Deposited On:06 Feb 2009 17:17
Last Modified:06 Feb 2009 16:17

Citation

Bosáček, Vladimír; Vratislav, Stanislav; Dlouhá, Mája (2004) Bridging Methoxy Groups in NaY, NaX and NaLSX Zeolites. Collection of Czechoslovak Chemical Communications, 69 (8). pp. 1537-1552. ISSN 0010-0765

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