NUCLEAR MAGNETIC-RESONANCE STUDY OF THE EXCHANGE KINETICS OF WATER PROTONS BETWEEN THE ALPHA-CAGE AND BETA-CAGE OF TYPE-A ZEOLITES - INFLUENCE OF PREPARATION METHODS ON ALUMINUM COMPOUND OCCLUSION AND STRUCTURAL INTEGRITY

NMR relaxation time measurements have been made over a temperature range 150-530 K on samples of sodium type A zeolite prepared by different methods. A distinct influence of occluded aluminum compounds in α as well as in β cages, the amount of which depends on preparation methods used, is observed. Also exchange rates differ considerably and indicate an exchange of water much faster in type A zeolite than in faujasites. In the β cages, no ordinary water molecules are found. In contrast to the situation in faujasites, there seem to be OH groups only formed by the occluded aluminum in freshly prepared samples as well as after loading the degassed zeolite with water. © 1979 American Chemical Society.