A neutron diffraction study of chemisorbed methyl groups in the structure of Y zeolite

Abstract

A powder diffraction study of the structure of NaY zeolites with chemisorbed CD 3 + species created by a reaction of Na + cations with d-methyliodide show that chemisorbed methyl groups are preferentially located in alfa cages at O(1) oxygen sites. A complete set of the structural parameters in the frame of Fd3m space group for unperturbed NaY with NaY after the formation of surface methoxy groups were given and an influence of chemisorbed species on the distribution of Na + cations in the lattice was detected by neutron diffraction. Our results show that the population of cationic sites has been changed significantly after the chemisorption of methyl iodide. While the occupation of S II in NaY without adsorbate was 32 Na + per unit cell (i.e. 100%), after the chemisorption of CH 3I it was found to be 19.6 (61%) and in case of CD 3I 21.4 (67%). On the same samples also a significant decrease of population in S I′ was detected accompanied by a slight increase of population in S I sites.