SORPTION OF METHANOL ON ZEOLITE HBETA INVESTIGATED BY IN-SITU MAS NMR-SPECTROSCOPY

Methanol adsorption and desorption experiments were performed on acidi c zeolites applying a new in situ MAS NMR technique. H-1 MAS NMR spect ra of dehydrated zeolites were recorded during injection of nitrogen g as loaded with methanol into the MAS rotor. The spectra indicated that in zeolite HBeta also silanol groups are involved in the adsorption o f methanol which is in contrast to the behaviour of SiOH groups in zeo lites HZSM-5 and HY. The desorption experiments show that about 70% of the methanol molecules contributing to adsorbate complexes in zeolite HBeta are weakly hydrogen-bonded at silanol groups.