Insight into the ADOR zeolite-to-zeolite transformation: the UOV case

Kasneryk, Valeryia; Shamzhy, Mariya; Opanasenko, Maksym; Wheatley, Paul; Morris, Russell E.; Čejka, Jiřı́

doi:10.1039/c7dt03751a

Cited by 19 publications

(22 citation statements)

References 35 publications

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“…Recent researches have been also focused on tailoring the acidity by alumination of germanosilicate zeolites characterized by unidirectional location of Ge-enriched D4R units, e.g. medium-pore ITH, 132,167,168 large-pore IWW, 169 UOV, 170 IWR 171 , and extra-large pore UTL 164 . Strategy proposed for post-synthesizing functionalization of extra-large pore UTL zeolite via isomorphous incorporation of Sn atoms (top).…”

Section: Dealumination-metallationmentioning

confidence: 99%

New trends in tailoring active sites in zeolite-based catalysts

et al. 2019

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Section: Dealumination-metallationmentioning

confidence: 99%

New trends in tailoring active sites in zeolite-based catalysts

et al. 2019

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“…Using neutral conditions or 0.1 m HCl, the UOV germanosilicate has been converted to the novel, layered ICP‐12P material. [ 127 ] Suitable conditions for the hydrolytic 3D–2D transition were not found for ITH and IWW germanosilicates; while ≈80% of framework Ge was leached in liquid water, the 3D structure remained. [ 112,128 ] Based on a systematic NMR investigation of ITH (Si/Ge = 4.5), IWW (Si/Ge = 5.6), and UTL (Si/Ge = 5.4) treated with water, the differences were proposed to depend on the distribution of Ge atoms in the d4r .…”

Section: Reactive Interaction Of Water With Zeolitesmentioning

confidence: 99%

Zeolite (In)Stability under Aqueous or Steaming Conditions

et al. 2020

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zeolites, modification of zeolite acidity for use as fluid catalytic cracking (FCC) catalysts or even for the preparation of novel zeolite frameworks. [1] Considering the significance of zeolite applications at the industrial level, a thorough understanding of zeolite (in)stability under aqueous conditions has been identified as a very important problem in catalysis and zeolite science. Zeolite (in)stability in water or under steaming conditions has been investigated by a number of experimental techniques, in particular magic angle spinning (MAS) NMR, IR, powder X-ray diffraction (PXRD), calorimetry and adsorption. Experimental studies have often been augmented by computational modeling and a large number of relevant theoretical papers can be found in the literature. While the main focus of this review is on reactive interactions of water with zeolites, it is also important to review the most important observations obtained for nonreactive water adsorption in zeolites. It is not surprising that all-silica zeolites, which exhibit negligible water uptake are stable even under conditions where Alcontaining zeolites lose crystallinity: the effective framework hydrolysis can only take place when sufficient water is present in the zeolite channel system. The amount of water inside the zeolite channels depends critically on the concentration of heteroatoms and/or framework defects, such as silanol nests, which show much higher affinity toward water than hydrophobic SiOSi bridges. Zeolite hydrophobicity increases with increasing Si/Al ratio and incomplete pore filling by water is commonly observed for zeolites with high Si/Al at standard pressure. It has been suggested already in the 1950s by Young that water can only adsorb on surface silanol groups, while the parts of the silica surfaces formed by SiOSi bridges are hydrophobic. [2] Both water adsorption in zeolites and zeolite (in)stability under aqueous conditions depend on the zeolite composition (Si/Al ratio, charge-compensating cations, and defect concentration in particular). Our primary goal is to review the most critical aspects of zeolite (in)stability for a broad range of temperature and partial water pressure (p 0), focusing on the framework zeolite composition (Si/Al ratio and presence of Ge, Sn, and Ti heteroatoms) and defect concentration. Zeolites (in)stability in water is discussed for increasing extent of framework degradation, starting from the nonreactive interaction with water, reversible hydrolysis of TO bonds, mild zeolite demetallation, mesopore formation, and total amorphization (Figure 1). Zeolites are among the most environmentally friendly materials produced industrially at the Megaton scale. They find numerous commercial applications, particularly in catalysis, adsorption, and separation. Under ambient conditions aluminosilicate zeolites are stable when exposed to water or water vapor. However, at extreme conditions as high temperature, high water vapor pressure or increased acidity/basicity, their crystalline framework can be destroyed....

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“…In contrast to zeolite UTL, where two new zeolite structures (OKO (Oppervlakte en Katalyse One) and PCR (IPC-4 (four))) form from condensing the layered precursors via calcination, the layered structure, IPC-5P, tends to maintain the original IWW framework after calcination. Additionally, the ADOR transformation of a germanosilicate parent zeolite with a UOV topology produces a new zeolite named IPC-12 [207,208]. During this transformation, the pore system shifts from two dimensional, containing 12-MR and 8-MR channels along the [100] direction intersecting with a 10-MR channel, to a one dimensional pore system without the 10-MR intersecting channel.…”

Section: D Layers From 14-and/or 12-mr Zeolite (Utl Iww Uov Saz-1mentioning

confidence: 99%

Two-Dimensional Zeolite Materials: Structural and Acidity Properties

Schulman

Liu

2020

Materials

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Zeolites are generally defined as three-dimensional (3D) crystalline microporous aluminosilicates in which silicon (Si4+) and aluminum (Al3+) are coordinated tetrahedrally with oxygen to form large negative lattices and consequent Brønsted acidity. Two-dimensional (2D) zeolite nanosheets with single-unit-cell or near single-unit-cell thickness (~2–3 nm) represent an emerging type of zeolite material. The extremely thin slices of crystals in 2D zeolites produce high external surface areas (up to 50% of total surface area compared to ~2% in micron-sized 3D zeolite) and expose most of their active sites on external surfaces, enabling beneficial effects for the adsorption and reaction performance for processing bulky molecules. This review summarizes the structural properties of 2D layered precursors and 2D zeolite derivatives, as well as the acidity properties of 2D zeolite derivative structures, especially in connection to their 3D conventional zeolite analogues’ structural and compositional properties. The timeline of the synthesis and recognition of 2D zeolites, as well as the structure and composition properties of each 2D zeolite, are discussed initially. The qualitative and quantitative measurements on the acid site type, strength, and accessibility of 2D zeolites are then presented. Future research and development directions to advance understanding of 2D zeolite materials are also discussed.

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Insight into the ADOR zeolite-to-zeolite transformation: the UOV case

Cited by 19 publications

References 35 publications

New trends in tailoring active sites in zeolite-based catalysts

New trends in tailoring active sites in zeolite-based catalysts

Zeolite (In)Stability under Aqueous or Steaming Conditions

Two-Dimensional Zeolite Materials: Structural and Acidity Properties

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