In Situ Generation by Cyclization of an Organic Structure Directing Agent for the Synthesis of High Silica Zeolite ERS‐7

Zeolites with high framework Si/Al ratios are of interest for industrial applications due to their hydrothermal stability. They are usually synthesized in the presence of pre‐prepared organic structure directing agents (OSDAs). The high silica ERS‐7 zeolite (topology type ESV) can be crystallized using N, N‐dimethylpyrrolidinium (dmpyrr) that is formed in situ via cyclization of N, N, N’, N’‐tetramethyl‐1,4‐diaminobutane (tmdab) when a cationic polymer is also present. The in situ generation of dmpyrr is demonstrated by solid‐state ¹³C NMR spectroscopy and supported by both chemical analyses and comparative syntheses using pre‐prepared dmpyrr. The cationic polymer inhibits the crystallization of mordenite, which is otherwise observed to be the favored product. The ERS‐7 prepared via in situ dmpyrr synthesis (Si/Al = 14) is characterized by PXRD and solid‐state NMR spectroscopy. The CO₂ adsorption seen for the H‐ and Na‐forms indicates interactions with accessible Na+ cations. The synthetic studies indicate the potential for in situ generation of OSDAs to reduce the need for extended OSDA syntheses.