Synthesis and Structural Features of Zeolite ZSM-3

Kokotailo, G. T.; Ciric, Julius

doi:10.1021/ba-1971-0101.ch008

Cited by 42 publications

(13 citation statements)

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“…We propose that under appropriate conditions the EMT is the first kinetic, metastable product in this synthesis field, followed by conversion into the more stable cubic FAU and more dense SOD structures. This hypothesis is strongly supported by several reports on EMT/FAU intergrowths (9)(10)(11)(12)(13)(14). Indeed, we suggest that it may be possible to capture other important zeolite phases that occur as intergrowths by exploiting the very early stages of synthesis and thus avoiding the use of organic reagents that are commonly needed to stabilize the desired phases.…”

Section: Rtss-a Vaccine With Many Maybes Extrasolar? Extra Strangesupporting

confidence: 84%

Capturing Ultrasmall EMT Zeolite from Template-Free Systems

Chateigner

Bein

et al. 2012

Science

267

202

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Small differences between the lattice energies of different zeolites suggest that kinetic factors are of major importance in controlling zeolite nucleation. Thus, it is critical to control the nucleation kinetics in order to obtain a desired microporous material. Here, we demonstrate how careful investigation of the very early stages of zeolite crystallization in colloidal systems can provide access to important nanoscale zeolite phases while avoiding the use of expensive organic templates. We report the effective synthesis of ultrasmall (6- to 15-nanometer) crystals of the large-pore zeolite EMT from template-free colloidal precursors at low temperature (30°C) and very high yield.

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Section: Rtss-a Vaccine With Many Maybes Extrasolar? Extra Strangesupporting

confidence: 84%

Capturing Ultrasmall EMT Zeolite from Template-Free Systems

Chateigner

Bein

et al. 2012

Science

267

202

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“…In some materials, twin faults were observed to occur close to one another, suggestive of a superlattice structure (Audier et al 1982). Kokotailo & Ciric (1976) reported a recurrently twinned ca. 7 nm superstructure in ZSM-3 materials based on selectedarea electron-diffraction data, implying that ZSM-3 contained ca.…”

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confidence: 99%

Intergrowth segregation in FAU-EMT zeolite materials

Treacy

Vaughan

Strohmaier

et al. 1996

Proc. R. Soc. Lond. A

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Intergrowths of cubic (fau) and hexagonal (em t) structural phases in a number of faujasite-related zeolite materials have been studied using transmission electron mi croscopy, and high-resolution powder X-ray diffraction. In Y, CSZ-1, CSZ-3, ZSM-2, ZSM-3, ZSM-20, ECR-35, ECR-30 and EMC-2 materials, the fau and emt com ponents segregate non-randomly into contiguous blocks. This segregation is most pronounced in ZSM-20 and ECR-35. ECR-30 and EMC-2 are both predominantly emt framework materials, within which fau intergrowths occur in clumps of 1, 2 or 3 layers. No evidence is found for extended superlattice ordering of intergrowths. Intergrowth segregation acts to reduce both the configurational entropy associated with the stacking statistics and the elastic energy associated with coherency strain. In tr o d u c tio nIt was first reported by Breck (1974) that the cubic faujasite (fau) framework could support recurrent twinning on 111 planes to produce a hexagonal framework struc ture. The hexagonal framework possesses straight 12-ring channels axially aligned along the six-fold axis, each channel being connected to its six neighbours through the 12-ring apertures of a secondary cage. It has been referred to in the literature as 'Breck structure 6' (bss)-in reference to Breck's list of six frameworks, including the faujasite framework fau, that can be generated by connecting sodalite cages (Breck 1974), and, erroneously, as 'hexagonal faujasite'. More recently, the Structure Com mission of the International Zeolite Association has assigned the framework code emt to the hexagonal polymorph, with material EMC-2 designated as the type species (Meier & Olson 1992; Newsam Sz Treacy 1993).Evidence for the existence of domains of the emt framework was originally limited to sightings of twin faults in fau framework materials. The framework in the vicinity of each twin plane would support cages that, locally, were topologically equivalent to those found in the emt framework. Audier et al. (1982) observed low densities of 111 twin planes in transmission electron micrographs of zeolite Y samples. In some materials, twin faults were observed to occur close to one another, suggestive of a superlattice structure (Audier et al. 1982). Kokotailo & Ciric (1976) reported a recurrently twinned ca. 7 nm superstructure in ZSM-3 materials based on selectedarea electron-diffraction data, implying that ZSM-3 contained ca. 20% of EMT-type cages.

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“…formation [36]. In a clear sol sodium aluminosilicate composition, FAU/EMT intergrowths were observed, and lead to mesoporosity, and cryo-TEM shows the coexistence of these crystals at early times of synthesis [37].…”

Section: Discussionmentioning

confidence: 94%

Synthesis method for introducing mesoporosity in a faujasitic-like zeolite system from a sodium aluminosilicate gel composition

Wang

Dutta

2017

Microporous and Mesoporous Materials

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We report a facile synthesis method of hierarchical faujasitic structures from a sodium aluminosilicate composition. The critical experimental variable was the removal of water via heat from the aluminosilicate gel during the synthesis process. These gels were used as starting materials for synthesis. With these partially dehydrated gels, extensive zeolite nucleation did occur, and the extent was varied both with the degree of dehydration and the temperature at which the dehydrated sample was maintained. Nanoparticles of FAU and EMT were formed that pack together resulting in external surface areas of 249-259 m 2 /g. In addition, under certain conditions of crystal growth, sheet like-structures arising from FAU-EMT intergrowths were observed. The interpenetration packing of the nanosheets lead to zeolitic particles with external surface areas in the range of 127-199 m 2 /g. The pore size distribution varied with sample preparation and ranged from 2-100 nm. These samples were characterized by N 2 adsorption, Xray diffraction and electron microscopy. The thermal and hydrothermal stability was also studied. In order to evaluate the role of the higher external surface area on a chemical reaction, the dealkylation of 1,3,5-triisopropylbenzene was examined and the product distribution did reflect the mesoporous nature of the sample.

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Synthesis and Structural Features of Zeolite ZSM-3

Cited by 42 publications

References 0 publications

Capturing Ultrasmall EMT Zeolite from Template-Free Systems

Capturing Ultrasmall EMT Zeolite from Template-Free Systems

Intergrowth segregation in FAU-EMT zeolite materials

Synthesis method for introducing mesoporosity in a faujasitic-like zeolite system from a sodium aluminosilicate gel composition

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