17O DOR and other solid-state NMR studies concerning the basic properties of zeolites LSX

We demonstrate complementary H-1, O-17, Al-27 and Si-29 measurements for basic low-sitica-X zeolites, which were unloaded and pyrrole and formic acid-loaded. It was found that the acid-base-system is not stabile, if the loading exceeds one pyrrole molecule or two formic acid molecules per supercage. O-17 DOR NMR spectra exhibit at least four lines, which are broadened by a distribution of chemical shifts in a similar extend as the Si-29 MAS NMR spectra are broadened by distribution of Si-O-Al angles. A strong cation influence upon O-17 shifts was observed. But there was no strong influence of the acid molecules on the mean value of the O-17 shift of the spectra. (C) 2009 Elsevier Inc. All rights reserved.