| Summary: | Zeolite A has several attributes which make it attractive as a solid acid catalyst. The
framework has pores on the order of 4-5 Å which show a strong selectivity toward small
molecules by excluding species with larger diameters than linear hydrocarbons. The pores
intersect to form a 3-dimensional channel network which is advantageous as it allows for free
diffusion throughout the entire structure. Furthermore, zeolite A is already commercially
available and is inexpensive to produce. Acidic forms of zeolite A , however, have long been
considered unachievable as a result of the reduced stability of the zeolite A framework
compared to those of more siliceous zeolites.
This thesis describes the preparation and characterization of a series of zeolite A
materials which demonstrate both thermal stability and Bronsted acidity. Zeolite A materials
were prepared whose frameworks contained both C a ²⁺ and NH₄⁺ ions. The three materials
studied had Ca ²⁺: NH₄⁺ ratios of 70:30, 60:40, and 50:50. The materials were systematically
examined using powder X-ray diffraction, electron microscopy, solid-state NMR, and gas
physisorption to establish their homogeneities and thermal stabilities. Finally, catalytic
testing of the materials for the conversion of methanol to olefins was carried out to establish
their activity in a model acid-catalyzed reaction.
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