(725f) Microporous Aluminophosphate Synthesis In Ionic Liquids

Zeolitic molecular sieves have extensive applications in catalysis and separations. These stable, crystalline materials with nanometer-sized pores can have a wide range of chemical compositions, such as silicates, phosphate metal oxides, or all-carbon molecular sieves. Subsequently, there has been extensive research on the synthesis of new frameworks as well as trying understanding their crystallization mechanism.¹  Crystalline molecular sieves traditionally are prepared using a hydrothermal synthesis method. A typical zeolite synthesis would consist of a mixture of water, a source of the framework atoms, a mineralizing agent (e.g. OH^- or F^-), and a structure-directing agent (SDA).  In the recent literature, it has been shown that aluminophosphate molecular sieves can be prepared ionothermally.²  In ionothermal synthesis, an ionic liquid serves as the solvent and often the structure directing agent as well.            Our group has focused on the ionothermal synthesis of porous, crystalline aluminophosphates and silicates with the emphasis on determining how the ionic liquid properties influence the final materials.  In particular, we are investigating the interactions between the ionic liquid solvent and the molecular sieve precursors prior to the synthetic reaction through solubility and spectroscopic measurements.  In this presentation, we will discuss the effects of reaction composition and conditions on structures of the porous aluminophosphate molecular sieves (AlPOs) and compare to those using traditional hydrothermal techniques. We also will discuss the influence of the ionic liquid structure on the resulting materials and will present our results from investigating the influence of the ionic liquid structure on the solubility of the precursors and the ionic liquid-precursor complexes seen by NMR and FTIR spectroscopy.

1.         J. Yu, Stud. Sur. Sci. Catal., 2007, 168, 39-104.

2.         Cooper, E. R.et. al., Nature 2004, 430, 1012-1016.