LOW-TEMPERATURE H-1 MAS NMR AND FTIR INVESTIGATIONS ON THE INTERACTION OF TETRACHLOROETHYLENE WITH SURFACE HYDROXYL-GROUPS IN H-ZEOLITES

The interaction of surface hydroxyl groups in zeolites with adsorbed C 2Cl4 molecules was investigated by low-temperature H-1 MAS NMR and FTI R spectroscopy. It could be shown that the induced H-1 NMR chemical sh ift Delta delta of free surface hydroxyl groups caused by the adsorpti on of C2Cl4 reflects the strength of acidity of the hydroxyl groups. A linear correlation between Delta delta and the induced wavenumber shi ft Delta v of the stretching vibration band of the surface hydroxyl gr oups has been found. Therefore, Delta delta can also be used for the c alculation of the deprotonation energy Delta E(DP) of surface hydroxyl groups by a previously developed method.