Germanosilicate Precursors of ADORable Zeolites Obtained by Disassembly of ITH, ITR, and IWR Zeolites

Shamzhy, Mariya; Opanasenko, Maksym; Tian, Yuyang; Konysheva, K. M.; Швец, А. В.; Morris, Russell E.; Čejka, Jiřı́

doi:10.1021/cm502953s

Cited by 66 publications

(101 citation statements)

References 45 publications

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“…Indeed, a number of MOFs and zeolites, unattainable through traditional techniques, have already been prepared by innovative methods such as transmetallation, solvent‐assisted linker exchange (SALE), assembly‐disassembly‐organization‐reassembly (ADOR), ball milling and other means . The ADOR method uses weaknesses in structures, created selectively by replacing silicon by other elements [boron (B) or germanium (Ge)], to synthesize new zeolites . The core idea is: first, to replace silicon with B or Ge, and then selectively remove heteroatoms from zeolites using acid hydrolysis.…”

Section: Figuresupporting

confidence: 62%

Little Thermodynamic Penalty for the Synthesis of Ultraporous Metal Organic Frameworks

Akimbekov

Navrotsky

2016

ChemPhysChem

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Many metal-organic frameworks (MOFs) of ultrahigh porosity (with molar volumes more than ten times greater than those of the corresponding dense phases) have been synthesized. However, the number of possible structures far exceeds those that have been made. It is logical to ask if there are energetic barriers to the stability of ultraporous MOFs or whether there is little thermodynamic penalty to their formation. Herein, we show that although the molar volumes of MOF-177 and UMCM-1 reach ultrahigh values, their energetic metastability is in the same range (of 7-36 kJ mol(-1)) as that seen previously for other porous materials. These findings suggest that there is little thermodynamic penalty for the synthesis of structures with varying porosity, and hence, ultraporous frameworks are energetically accessible. Therefore, innovative synthesis methods have the possibility to overcome the drawbacks of conventional approaches and greatly extend the number, porosity, and properties of new framework materials.

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Section: Figuresupporting

confidence: 62%

Little Thermodynamic Penalty for the Synthesis of Ultraporous Metal Organic Frameworks

Akimbekov

Navrotsky

2016

ChemPhysChem

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“…But it is not always the case. [ 110 ] It was found that low concentration acid solution and low temperatures favored the hydrolysis process, and the effi ciency was strongly related with the chemical composition of the parent zeolites. In some cases, Ge-rich D 4 R units distribute only along one direction and act as pillars supporting the silica layers, such as in germanosilicates with UTL, [ 101,105 ] ITH, [ 106 ] IWW [ 107 ] topologies.…”

Section: Top-down Methods To 2d Zeolites and Ador Process To Novel Zeomentioning

confidence: 99%

Recent Advances in the Synthesis and Application of Two‐Dimensional Zeolites

Sun

2016

Advanced Energy Materials

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traditional hydrothermal syntheses would produce intermediate materials with 2D feature, such as MCM-22P, [ 7,8 ] PREFER, [ 9 ] which are composed of crystalline zeolite layers with the unit-cell thickness stacking on top of each other in ordered or disordered patterns. [10][11][12][13][14][15] Unlike traditional 3D zeolites, the crystal growth of frameworks in 2D layered zeolites is restricted in one particular direction, leaving lots of hydroxyl groups on layer surface. As zeolites are normally defi ned as 3D materials that possess regular micropore systems and consist of TO 4 tetrahedra, layered zeolite precursors containing silanols could not be regarded as zeolites in the strictest sense, but they are broadly included in the family of zeolite materials. Thus, the as-synthesized 2D zeolites are often denoted as layered zeolite precursors (the typical examples are shown in Table 1 ), [7][8][9] which would transform into their 3D order/disorder counterparts after removing organic molecules and condesation of interlayer silanols via calcination. [ 10 ] In the early research stage, the layered zeolite precursors are discovered accidentally in traditional hydrothermal syntheses, because we have limited control over the traditional synthesis process due to the incomplete understanding of crystallization mechanism. At that stage, one of the most attractive features of 2D zeolites is that they could transform into zeolite materials with hierarchical architectures. In some cases, the traditional synthesis produces hierarchical layered material, such as MCM-56, [ 26 ] in which the crystalline zeolite layers disorderly stacked. Furthermore, the recognition that the obtained layered precursors could be modifi ed into various hierarchical zeolite structures (such as delaminated, pillared, interlayer expanded and others) make them signifi cantly different from conventional 3D zeolite materials with rigid structures. Thus, the construction of hierarchical zeolite materials from the perspective of 2D layered zeolite precursors is an important research aspect during the past few years.With the improved synthetic techniques, layered zeolites are not only increasing in number, but also expanding the notion in composition and structure. One remarkable breakthrough in recent years is the discovery of 2D MFI nanosheets with the single unit-cell thickness (about 2 nm), which is achieved by adopting Gemini-type bifunctional surfactants as organic structure-directing agent (OSDA) in hydrothermal synthesis. [ 49 ] The calcined MFI nanosheets become a special kind of hierarchical zeolites Two-dimensional (2D) zeolites, originating from lamellar precursors, are a special kind of porous materials, in which crystalline zeolite nanolayers are weakly assembled in one particular direction. As there is no covalentbond between layers, the stacking sequences could be manipulated and possibly controlled to derive a family of zeolitic materials with structural diversity. The research on 2D zeolites arises from the primary casual discovery during ...

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“…4C). The formation of extra-porosity not observing during the alumination of Ge-poor ITH-6 zeolite treatment with Al(NO 3 ) 3 solution is likely caused by "unsuitable" distribution of extractable Ge atoms in the framework (the absence of [4Si;4Ge] 25 domains according to the NMR data 23 ). (Fig.…”

Section: Ith-n/al/80 (Blue) and Ith-n/al/175 (Red)mentioning

confidence: 99%

“…Since the conditions of the treatment (pH = 2.0, T = 80 or 175 °C) are sufficient for extraction of the most Ge from the framework ( Table 2), it is 5 reasonable to assume that the first stage of overall process is the breaking of Si-O-Ge bonds in D4Rs. 23 This leads to the formation of silanol defects in all ITH zeolites under investigation (Fig. 5A) as well as to the creation of ultramicroand mesopores in ITH-1 or ITH-2 zeolites (Fig.…”

mentioning

confidence: 99%

Post-synthesis incorporation of Al into germanosilicate ITH zeolites: the influence of treatment conditions on the acidic properties and catalytic behavior in tetrahydropyranylation

Shamzhy

Opanasenko

Ramos

et al. 2015

Catal. Sci. Technol.

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Post-synthesis alumination of germanosilicate medium-pore ITH zeolite was shown to be an effective procedure for tuning its acidity. The treatment of ITH zeolites synthesized with different chemical compositions (i.e. Si/Ge = 2.5; 4.4; 5.8) with Al(NO 3 ) 3 aqueous solution led to the formation of strong 10 Brønsted and Lewis acid sites and an increasing fraction of ultramicro-and mesopores in Ge-rich ITH samples (Si/Ge = 2.5 and 4.4). The concentration of Al incorporated in the framework increases with decreasing Si/Ge ratio in the parent ITH. The increasing temperature of alumination from 80 to 175 °C (HT conditions) resulted in 1) 1.5 -2-fold increase in the concentration of Brønsted acid sites formed; and 2) in decreasing fraction of framework Al atoms detectable with base probe molecules (i.e. pyridine, 15 2,6-di-tert-butyl-pyridine), i.e. an increased concentration of the "inner" acid sites. The activity of prepared Al-substituted ITH zeolites in tetrahydropyranylation of alcohols is enhanced with increasing amount of accessible acid sites in bulky crystals (e.g. alumination at lower temperature) or with growth the total concentration of acid centres within tiny ITH crystals (e.g. alumination under HT conditions). This trend became more prominent with increasing kinetic diameter of substrate molecules under 20 investigation (methanol < 1-propanol < 1-hexanol).

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Germanosilicate Precursors of ADORable Zeolites Obtained by Disassembly of ITH, ITR, and IWR Zeolites

Cited by 66 publications

References 45 publications

Little Thermodynamic Penalty for the Synthesis of Ultraporous Metal Organic Frameworks

Little Thermodynamic Penalty for the Synthesis of Ultraporous Metal Organic Frameworks

Recent Advances in the Synthesis and Application of Two‐Dimensional Zeolites

Post-synthesis incorporation of Al into germanosilicate ITH zeolites: the influence of treatment conditions on the acidic properties and catalytic behavior in tetrahydropyranylation

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