Kinetics of ammonia penetrating into the sodalite units of sodium faujasites studied by nuclear magnetic resonance

Pulsed proton NMR, which is able to distinguish between molecules in large cavities and in the small pores, as the latter give rise to a fast-decaying part in the free induction decay, gave a first-order rate equation for ammonia penetration into a sodalite unit expressed as penetration half-times. The activation energy was 120 kj/mole, and there was no rate difference between X and Y zeolites.