# Understanding the Mechanism of Nontraditional Zeolite Synthesis Using In Situ Nuclear Magnetic Resonance Spectroscopy and X‑ray Diffraction

## TL;DR

This study uses NMR and X-ray diffraction to understand how nontraditional zeolites form through the ADOR process.

## Contribution

The study reveals new mechanistic details of zeolite synthesis using in situ NMR and XRD.

## Key findings

- Local structural changes in water reactions are modeled as one disassembly process.
- Acid reactions involve two processes: disassembly and interlayer rearrangement.
- In situ methods show both local and long-range changes are needed to understand the reaction.

## Abstract

In situ solid-state nuclear magnetic
resonance
(NMR) spectroscopy and in situ powder X-ray diffraction
(PXRD) experiments are used to develop mechanistic insights into the
disassembly and organization steps of nontraditional zeolite synthesis
using the ADOR (Assembly, Disassembly, Organization, Reassembly) process.
The work focuses on the reaction of the germanosilicate zeolite UTL
to form two ADOR intermediates: IPC-1P on reaction with water and
IPC-2P on reaction with aqueous HCl. The changes in the local structure
on reaction with water can be modeled as one overall disassembly process,
but the long-range changes, as measured by changes in interlayer spacing
determined by XRD, indicate multiple stages of the reaction as the
layer structure develops. For the reaction with aqueous acid, the
local changes are modeled with two processes: a disassembly and an
interlayer rearrangement (organization step). However, only one major
stage of change is seen in the XRD measurements. The new details revealed
by the in situ studies demonstrate that both local
(probed by NMR spectroscopy) and long-range (probed by XRD) changes
to the structure are required to truly understand how the reaction
proceeds. The results provide new insights into the relative kinetics
of the different processes involved in the reactions under different
conditions and reveal new features such as staging in the layer stacking
changes in the organization step.