AN 134 ACID SITES TPD

Characterization of Acid Sites Using Temperature-Programmed Desorption

Temperature-Programmed Desorption (TPD) is one of the most widely used and flexible techniques for characterizing the acid sites on oxide surfaces1-5. Determining the quantity and strength of the acid sites on alumina, amorphous silica-alumina, and zeolites is crucial to understanding and predicting the performance of a catalyst. For several significant commercial reactions (such as n-hexane cracking, xylene isomerization, propylene polymerization, methanol-to-olefins reaction, toluene disproportionation, and cumene cracking), all reaction rates increase linearly with Al content (acid sites) in H-ZSM-56-11. The activity depends on many factors, but the Brønsted-acid site density is usually one of the most crucial paramete