Theoretical investigation of layered zeolite frameworks: Interaction between IPC-1P layers derived from zeolite UTL

Advances in theory and their application within the field of zeolite chemistry

“…Sastre et al 118 found a linear correlation between the Si-O-Ge angle and the energy of the framework for AST, ASV, BEA, BEC, ISV and LTA zeolites using a force field approach. 122 The non-local exchange-correlation functional vdW-DF2 gives an excellent agreement for the interaction energy between the layers. Kamakoti et al used DFT calculations to demonstrate for BEC that Ge is not only more stable in the D4R, it is also preferably clustered in a four-ring.…”

Layered zeolitic materials: an approach to designing versatile functional solids

“…198 It is the case of IM-12 zeolite (also UTL-type germanosilicate and isostructural to ITQ-15) 193 which is transformed in so-called COK-14 material through the dislodging germanate four-rings from acid leaching and successive annealing calcination treatment. 199 However, up to now, only successful results have been obtained with germanosilicates, involving the previous elimination of germanium-rich structural units.…”

Expansion of the ADOR Strategy for the Synthesis of Zeolites: The Synthesis of IPC‐12 from Zeolite UOV

“…[6] Of potential great importance is the possibility of preparing materials that do not obey the energy-density rules [7] associated with hydrothermal synthesis,l eading to new zeolites that in the past would have been thought unfeasible synthetic targets. [8] An important point to note is that the reassembly process is very easy to model, leading to final products that are computationally predictable, [9] something that is very difficult in hydrothermal synthesis.…”

“…The structure of the material has previously been predicted computationally and confirmed in our experiments using X-ray diffraction and atomic resolution STEM-HAADF electron microscopy. This is the first successful application of the ADOR process to amaterial with porous layers.For more than 60 years,z eolites have been almost exclusively prepared via hydrothermal, [1] solvothermal, [2] and ionothermal [3] synthesis techniques.T he recently discovered ADOR (assembly-disassembly-organization-reassembly) strategy [4] is an alternative way to prepare new zeolite structures.T he method consists of the chemically selective disassembly of aparent zeolite into its constituent layers.This is followed by organization of these units into as uitable relative orientation and the reassembly of the units into new materials.C ontrolled disassembly of the parent zeolite is possible when there is aw eakness engineered into the structure during the initial synthesis.[5] In general, this involves the regioselective substitution of silicon for germanium, which is much more hydrolytically sensitive than the silicon species,a llowing selective dissolution of the germanium out of the material.TheA DOR process is fundamentally different from hydrothermal synthesis in that the final framework-forming step is an irreversible condensation at high temperature (500-700 8 8C) rather than areversible crystallization step.This leads to new zeolites that have unusual properties that include the possibility of preparing isoreticular families of materials with continuously controllable porosity.[6] Of potential great importance is the possibility of preparing materials that do not obey the energy-density rules [7] associated with hydrothermal synthesis,l eading to new zeolites that in the past would have been thought unfeasible synthetic targets.[8] An important point to note is that the reassembly process is very easy to model, leading to final products that are computationally predictable, [9] something that is very difficult in hydrothermal synthesis.One crucial issue of the ADOR approach not yet demonstrated is its general applicability.U pt on ow,t he ADOR approach to new materials has concentrated on the use of zeolite UTL as the parent material, although other parent zeolites,s uch as IWW have been successfully disassembled.[10] Germanosilicate UTL is an ideal ADOR starting point because of its chemical composition and because of the stability of the layered units that are formed on disassembly.H erein we report the synthesis of an ew zeolite,w hich we name IPC-12, using the ADOR transformation of ag ermanosilicate parent zeolite with the UOV topology.[11] We have previously predicted that UOV would be agood target, [12] but since it has pores in three dimensions, rather than only in two as is the case for UTL,w ecould not rule out the possibility that the layers (which are porous) would be less stable than in UTL.Indesigning this successful procedure,p articular attention has to be given to the factors controlling the ADOR process,such as appropriate chemical and structural properties of the parent material, optimized conditions for disassembly and reassembly of formed intermediates.IPC-12 retains the same pore systems as UOV in one direction (viewed perpendicular to the bc crystallographic plane (see Figure 1), but has new structural features when viewed in the other two directions.T he structure of the new material has been confirmed using X-ray diffraction and atomic resolution STEM-HAADF electron microscopy. …”

“…[8] An important point to note is that the reassembly process is very easy to model, leading to final products that are computationally predictable, [9] something that is very difficult in hydrothermal synthesis.…”