Resumen de Synthesis and Characterization of Zeolite Na–Y and Its Conversion to the Solid Acid Zeolite H–Y
Terence E. Warner, Mads Galsgaard Klokker, Ulla Gro Nielsen
Zeolite Y has an iconic crystal structure, but more importantly, the hydrogen modification zeolite H–Y is the classic example of a solid acid which is used extensively as a catalyst in the oil industry. This metastable compound cannot be synthesized directly, which creates an opportunity to discuss various preparative strategies with the students, such as the three-stage procedure described here. Stage I concerns the hydrothermal synthesis of zeolite Na–Y, followed by ion-exchange with an ammonium acetate solution to form zeolite NH4–Y, and the latter is subsequently converted to zeolite H–Y by thermolysis. Stages II and III may instead be performed using commercially available zeolites, Na–Y and NH4–Y, respectively, which shifts the learning objectives to structural characterization of zeolites. The characterization of the product and intermediate materials gives the students a practical insight into the applicability and limitations of powder X-ray diffraction, solid-state nuclear magnetic resonance spectroscopy, and thermogravimetric analysis, and how these analytical tools complement each other. These aspects make its synthesis and characterization an ideal practical exercise for an upper-level undergraduate laboratory in inorganic or materials chemistry courses. Moreover, the methods and skills learned during this experiment enable the students to tackle more complex zeolites and related framework materials.
