Impact of Organic Templates on the Selective Formation of Zeolite Oligomers

Zeolites are essential materials to industry due to their adsorption and catalytic properties. The best current approach to prepare a targeted zeolite still relies on trial and error's synthetic procedures since a rational understanding of the impact of synthesis variables on the final structures is still missing. To discern the role of a variety of organic templates, we perform simulations of the early stages of condensation of silica oligomers by combining DFT, Brønsted‐Evans‐Polanyi relationships and kinetic Monte Carlo simulations. We investigate an extended reaction path mechanism including 258 equilibrium reactions and 242 chemical species up to silica octamers, comparing the computed concentrations of Si oligomers with 29SI NMR experimental data. The effect of the templating agent is linked to the modification of the intramolecular H‐bond network in the growing oligomer, which produces higher concentration of 4‐membered ring intermediates, precursors of the key double‐four ring building blocks present on more than 39 known zeolite topologies. DFT and kMC calculations are combined to investigate the impact of the most commonly used organic template molecules including the tetramethylamine cation (TMA+) both on the reaction energy profiles and the kinetics of formation of zeolite silica oligomers. The extended reaction path mechanism includes up to 258 equilibrium reactions. The templating agent is shown to produce higher concentration of 4‐membered ring intermediates.