Chemisorbed methyl groups in NaX and NaY types of zeolitic catalysts

Abstract

Powder neutron diffraction and 13 C MAS NMR methods were used in the structural parameters determinations of the NaX and NaY zeolites with chemisorbed methyl groups CD 3 or CH 3. Powder neutron experiments were carried out at 7 K on the KSN-2 diffractometer at the LVR-15 research reactor in Řež near Prague. The complete structural parameters were determined by Rietveld analysis of powder neutron patterns using the GSAS package. Difference Fourier maps were determined to localize the nonframework cations and the CD 3 groups. Experimental evidence of the created chemisorbed methyl groups after reaction of methyliodide with Na+ cations of the zeolite was obtained from 13 C MAS NMR spectra. The structural analysis of the NaX samples was treated in the frame of the Fd3 space group, the occupation numbers of cations and the location of CD 3 groups with center in the position 96g are given.