The relative stability of zeolite precursor tetraalkylammonium–silicate oligomer complexes

We present a combined DFT and MP2 level molecular modeling study relevant for the early stage of the synthesis of the MFI and MEL zeolite structures. We have carried out a series of DFT molecular dynamics simulations, in order to study the relative stability of the silicate oligomer precursors taking part in the synthesis process. Based on computed silica/template interactions, we present evidence of the influence of different structure directing agents on the relative stability of large silicate oligomer complexes. They are due to a combination of differences in the internal stability of the precursor complexes and the interactions of the particular template with the silicate oligomers.

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► Si11 oligomers connect to form different zeolite precursors.
► Particular ring structures interconnecting Si11 units are stabilized by SDAs.
► Internal precursor stability is combined with template interaction.