THE INFLUENCE OF OXYGEN ON THE H-1 MAS NMR-SPECTRA OF H-ZSM-5 ZEOLITES

H-1 MAS NMR spectra of H-ZSM-5 loaded with defined amounts of oxygen w ere measured at different temperatures, in order to investigate the in fluence of the paramagnetic oxygen molecules on the spectra. It could be shown that the second moment of the H-1 NMR signals is considerably enlarged even for relatively small amounts of adsorbed oxygen. This e ffect leads to a remarkable broadening of the spinning sideband patter n of the H-1 MAS NMR signals, especially at low temperatures.