STUDY OF ZEOLITE ACIDITY BY BROAD-LINE H-1-NMR AT 4K - COMPARISON WITH RESULTS OF H-1 HR-NMR (MAS) AT AMBIENT-TEMPERATURE

Simulation of 4K broad-line H-1 NMR spectra of solids, with Bronsted acid properties and loaded with known amounts of water, allows the determination of the concentrations of the species: H3O+, H2O...HO and of the remaining initial species: OH and H2O. This is an original method for studying the acid strength of solids. The following results concern HY zeolite taken as example. A parallel study using H-1 HR-NMR (MAS) at ambient temperature confirms the results obtained by using both methods on HZSM-5 (1).