PHYSICOCHEMICAL CHARACTERIZATION OF ZEOLITES SSZ-26 AND SSZ-33

Detailed characterization of zeolites SSZ-26 and SSZ-33 is presented a nd includes data from adsorption experiments, X-ray powder diffraction (XRD), electron diffraction (ED), and high-resolution electron micros copy (HREM). Simulated XRD patterns and HREM images of the proposed st ructures agree very well with all the experimental data. These zeolite s are the first synthetic high-silica molecular sieves to contain a th ree-dimensional pore system comprised of intersecting 10- and 12-ring ports. The structures of SSZ-26 and SSZ-33 are compared to the structu res of known zeolites, and the relationships between the geometry of t he structure-directing agents used in the synthesis of SSZ-26 and the geometry of the pores are analyzed using energy minimization calculati ons. Several hypothetical zeolite structures are derived based on the proposed models for SSZ-26 and SSZ-33. SSZ-26 and SSZ-33 are the first examples of molecular sieves whose multidimensional pore systems have been formed by the purposeful design of their structure-directing age nts.