Toward Controlling Disassembly Step within the ADOR Process for the Synthesis of Zeolites

The application of the Assembly-Disassembly-Organization-Reassembly (ADOR) protocol to the synthesis of germanosilicate zeolites has become a major milestone in material design by enabling the preparation of previously unknown isoreticular zeolites with tunable building units (i.e., -d4r-, - s4r-, -O-) connecting crystalline layers. Two processes operating in the disassembly step, deconstructive deintercalation and reconstructive rearrangement, determine the structure of ADOR-derived zeolites. However, independent management of these key ADOR processes, which would be desirable to regulate the characteristics of the products, has remained elusive thus far. Herein, we report a new method for controlling the primary steps of the ADOR process and present the first example of a cycled structural transformation of interlayer units (d4r -> s4r -> d4r) in the germanosilicate UTL zeolite under slow deintercalation/fast rearrangement conditions. The slow deintercalation mode of ADOR enabled us to prepare the previously known OKO, *PCS, IPC-7 zeolites via gradual reduction of interlayer units in UTL (d4r -> d4r/s4r -> s4r -> s4r/-O-), in contrast to conventional rearrangement-driven synthesis (-O-. s4r/-O- -> s4r...). X-ray powder diffraction (XRD), sorption, and solid-state NMR time-resolved studies revealed that the slow deintercalation/fast rearrangement modification of ADOR makes it possible to adjust the pore architecture of germanosilicate zeolites toward increasing their micropore size, which has never been achieved before in the classical ADOR mechanism. Therefore, slow deintercalation or slow deintercalation/fast rearrangement routes provide a tool for controlling the isoreticular zeolite structure. Ultimately, the results from this study may facilitate the design of previously predicted but inaccessible members of the ADORable zeolite family.

Automated summary

The application of the ADOR protocol in the synthesis of germanosilicate zeolites allows for the preparation of previously unknown isoreticular zeolites with tunable building units. Control over key ADOR processes can regulate the structure of the zeolites and adjust pore size, providing a new tool for design and synthesis.