Investigations of TsVM zeolite acidities with different degrees of exchange of Na+ by H+

The method of programmed thermal desorption of ammonia has been used to establish that on the surface of the sodium form of type TsVM zeolite having a modulus SiO2/Al2O3= 34.5 there are two types of acidic centers having ammonia desorption activation energies Ed equal to 40–45 and 80–100 kJ/mole. Replacement of Na+ by H+ leads to the appearance of a third type of center with a value ED=130–150 kJ/mole. In this case in the IR spectra of specimens saturated with ammonia a band appears at 1410 cm−1, which is evidence for the presence of NH 4 + ions. Increasing the degree of Na+ replacement by H+ leads to a nonproportional rapid increase in the concentration of highly energetic centers, which may be explained by the partial transfer of aluminum into cationic positions with the formation of additional acidic centers.