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Supercage(s) filled with one and multiple protonated structure directing agents.

Nanoporous filmCurrently available ultra-pore structures have frameworks with the largest channels in one dimension and no extraframework cationic sites. The former limits diffusion of guest molecules, while the latter prohibits formation of acid sites via techniques like ion exchange. To overcome such limitations, we use structure-directing agents (SDAs) and metal centers during synthesis to produce novel structures. We aim at characterization and post-synthesis treatment of a new type of transition metal substituted aluminophosphate having the highest metal-to-aluminum ratio of any large-pore zeolite type structure and is prepared using diamines as SDAs. The resulting molecular sieves have channels with 12-ring apertures in 2-D and 8-ring apertures in 1-D, with supercages measuring 20 x 20 x 15 Å3. Compared to that of faujasite, such cages are rather unusual and ideal for catalysis applications where high acid site concentration and large pores/void volume are critical. Conventional methods for removing organic templates from molecular sieves involve the use of air at high temperatures to break down and desorb the template via Hoffman elimination. Preliminary tests showed that a calcination process in oxygen-only atmosphere further damaged the material framework. Another SDA removal test using solvent extraction methods is capable of recovering void space in the micropore region, indicating that not all template molecules are protonated as previously thought. After removal of the SDA moiety, the porous frameworks are characterized and tailored for reactions catalyzed by acidic environments. Applications we are considering are the conversion of methanol and heavy oils to hydrocarbons (i.e., for production of transportation fuels). This project will collaborate with the CHM-UMass. This project is currently supported through the NSF CAREER Award CTS-0546370.