Studies on the use of faujasite as a reagent to deliver silica and alumina in building new zeolite structures with organo-cations

Interzeolite Conversion and the Role of Aluminum: Toward Generic Principles of Acid Site Genesis and Distributions in ZSM-5 and SSZ-13

“…The origin for the higher Al yield of 45% found in solids during the induction period of [TMAda] IZC versus the Al yield of 35% in [TPA] IZC is likely due to the ability of OSDA to interact with framework Al. 33 Whilst TMAda + appears to be small enough to diffuse through the pores of FAU as recently suggested by Zones, 33 the hydrated diameter of TPA + is bigger (7.6Å 78 ), and thus TPA + likely diffuses less easily through the largest micropore openings of FAU (7.35Å), 79 leading to a higher sorption potential of TMAda + on FAU remnants. The latter is confirmed by higher weight loss in TGA measured on multiple solids obtained after both 15 minutes and 1 h of oven time (data not shown).…”

“…'common building units' between mother and product zeolite), [27][28][29] however, it has been recently questioned whether such structural features are really vital for interzeolite conversion or seeded growth. [30][31][32][33][34] For example, FAU-to-MOR IZC (with MFI as intermediate metastable phase) has been reported (without the use of OSDA). 32 None of these structures have common building blocks and the MFIto-MOR transformation is one from a denser to a more open structure, which is unexpected from a thermodynamic perspective.…”

On the key role of aluminium and other heteroatoms during interzeolite conversion synthesis

“…In the majority of IZC cases no gels are formed, which simplies the mechanistic picture and has aided early IZC investigations such as those of Zones and co-workers. [53][54][55] Nonetheless, in-depth mechanistic IZC understanding is lacking.…”

“…101 Zones et al recently demonstrated OSDA exchange on (parent) zeolites proportional to the Al content at room temperature and also acknowledges its role at relevant IZC conditions. 53 The availability of a unique physicochemical context (from incongruent dissolution of crystalline sources) in IZC synthesis mixtures and a focus on the charge-balancing role of Al (and other charged species such as SDA) thus provides a new theory to explain inherently fast nucleation taking place in IZC mixtures. The commonly endorsed theory of structural elements ('nanoparts') facilitating nucleation and growth is challenged by new ndings on swi IZC between structurally non-resembling parent-daughters.…”

Study on the Synthesis of Chabazite Zeolites via Interzeolite Conversion of Faujasites

“…In this work, we used various faujasite sources (different Si/Al ratios) as aluminum reagents for chabazite synthesis. e transformation of FAU into CHA zeolite under similar synthesis conditions using TMAda as the OSDA has been reported [27,48]. Herein, we focused on the use of DMECHA as the OSDA to successfully synthesize CHA zeolites with various Si/Al ratios (Table 1).…”