Distribution of sodium cations and chemisorbed methyl groups in the structure of NaX and NaLSX zeolite catalysts by powder neutron diffraction and ~(13)C NMR

摘要

Powder samples of NaX and NaLSX faujasite (Si/Al = 1) in dehydrated state and with adsorbed methyl iodide were investigated by neutron diffraction and ~(13)C MAS NMR. The distribution of Na+ cations and chemisorbed methylium ions in the zeolite framework structure (faujasite type) was estimated using the GSAS package and difference Fourier maps. Surface methoxy groups were located mostly at O_1 and O_4 lattice oxygen. The changes in populations of cationic sites after chemisorption were detected.