Acidic properties of HZSM-5 using acetonylacetone, TPD of ammonia, and ftir of adsorbed pyridine

Abstract EN

The acidic properties of the commercial zeolite catalyst HZSM-5 (Si/Al = 25) were evaluated using different techniques.

Temperature programmed desorption (TPD) of ammonia showed the presence of both weak and strong acidic sites.

FTIR of adsorbed pyridine showed the presence of both Brönsted (1545.2 cm–1) and Lewis acidic sites (1445.1 cm–1).

Using the acetonylacetone method to assess the acid/basic properties in zeolites is a very interesting quantitative method that is not commonly used.

Using this method, we have shown that the active sites in this catalyst are not completely acidic, but some basic sites also exist, that cannot be detected by the other two methods.

Such understanding is very critical for reactions requiring an entirely acidic or basic surface