Few-Unit-Cell MFI Zeolite Synthesized using a Simple Di-quaternary Ammonium Structure-Directing Agent

Synthesis of a pentasil-type zeolite with ultra-small few-unit-cell crystalline domains, which we call FDP (few-unit-cell crystalline domain pentasil), is reported. FDP is made using bis-1,5(tributyl ammonium) pentamethylene cations as structure directing agent (SDA). This di-quaternary ammonium SDA combines butyl ammonium, in place of the one commonly used for MFI synthesis, propyl ammonium, and a five-carbon nitrogen-connecting chain, in place of the six-carbon connecting chain SDAs that are known to fit well within the MFI pores. X-ray diffraction analysis and electron microscopy imaging of FDP indicate ca. 10 nm crystalline domains organized in hierarchical micro-/meso-porous aggregates exhibiting mesoscopic order with an aggregate particle size up to ca. 5 mu m. Al and Sn can be incorporated into the FDP zeolite framework to produce active and selective methanol-to-hydrocarbon and glucose isomerization catalysts, respectively.

Automated summary

A novel pentasil-type zeolite material, named FDP, has been synthesized with ultra-small few-unit-cell crystalline domains, which can be used for producing highly active and selective catalysts. FDP is prepared using a di-quaternary ammonium structure directing agent and can incorporate Al and Sn into its framework to produce catalysts for methanol-to-hydrocarbon and glucose isomerization reactions, respectively. X-ray diffraction analysis and electron microscopy imaging show that FDP has crystalline domains of around 10 nm with hierarchical micro-/meso-porous aggregates exhibiting mesoscopic order.