A hydrothermal synthesis of a 2-dimensional layered silicate followed by a transition to a 3-dimensional aluminosilicate zeolite

Jackowski, Anna; Zones, Stacey I.; Chaudhuri, Kaustav; Lacheen, Howard S.; Yeh, Sung-Wei

doi:10.1016/j.micromeso.2014.05.030

Cited by 7 publications

(5 citation statements)

References 32 publications

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“…The structures for multidimensional large pore zeolites *BEA, BEC, IWS are shown in Figure , along with LTA. Interestingly, 1 , with an ortho ring substitution, does not make a 3D zeolite structure at the high Ge end, but simply stops at the stage of a layered product . On the other hand, the decrease of the addition of Ge moves the products to converge on the high silica *BEA, where there is less selectivity attributable to the OSDA isomers.…”

Section: Results and Discussionmentioning

confidence: 99%

“…Interestingly, 1, with an ortho ring substitution, does not make a 3D zeolite structure at the high Ge end, but simply stops at the stage of a layered product. 25 On the other hand, the decrease of the addition of Ge moves the products to converge on the high silica *BEA, where there is less selectivity attributable to the OSDA isomers. This happens as the ratio is fixed at 16/1, for example.…”

Section: Products From Diquaternary Osdas (1−3)mentioning

confidence: 99%

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Synthesis of Germanosilicate Molecular Sieves from Mono- and Di-Quaternary Ammonium OSDAs Constructed from Benzyl Imidazolium Derivatives: Stabilization of Large Micropore Volumes Including New Molecular Sieve CIT-13

et al. 2016

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A series of monoquaternary and diquarternary benzyl-imidazolium derivatives are prepared and used as organic structure direction agents (OSDAs) in germanosilicate syntheses. The goal of this work is to create new multidimensional large pore zeolites. For the OSDA made and tested, we looked for relationships based upon stereochemistry from the benzyl ring as part of each structure. Several known molecular sieves with the *BEA, BEC, IWS, or LTA topologies are obtained. Molecular modeling is carried out with the goal of understanding: (a) the product selectivity correlation with the OSDA and the zeolite obtained, and (b) why differential rates of crystallization are observed for isomers that lead to different zeolite products. Additionally, a new molecular sieve denoted CIT-13 is prepared and shown to possess intersecting 14-and 10-membered ring pores, which gives confidence to the soundness of this approach for OSDA construction to yield new multidimensional large pore zeolites. CIT-13 is the first molecular sieve to have this combination of pore sizes.

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Section: Results and Discussionmentioning

confidence: 99%

Section: Products From Diquaternary Osdas (1−3)mentioning

confidence: 99%

Synthesis of Germanosilicate Molecular Sieves from Mono- and Di-Quaternary Ammonium OSDAs Constructed from Benzyl Imidazolium Derivatives: Stabilization of Large Micropore Volumes Including New Molecular Sieve CIT-13

et al. 2016

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“…For example, two syntheses having the same overall composition but different reagents produced different zeolite products . In addition, a given zeolite product in solution is often metastable, having an opportunity to continue downhill in free energy toward recrystallization to increasingly denser framework structures, with quartz, having no microporosity at all, considering the eventual thermodynamically stable endpoint in silica materials. − It has been suggested that a strong van der Waals interaction of the guest molecule with the framework within the zeolite structure can be responsible for some selectivity in synthesis and subsequent stabilization (either thermodynamic or kinetic) of that product against the further cascade of reaction toward higher framework density. − , Zeolite synthesis starts in aqueous solution with the condensation of dissolved silicate species interacting with a dissolved organic molecule, the so-called structure-directing agent (SDA), leading to crystallization of a microporous product in which the SDA is contained in the zeolite cages. Thus, the transfer of the SDA, generally a fairly hydrophobic molecule, from the hydrophilic environment of the aqueous phase to the much less hydrophilic environment of the zeolitic pore, occurs during synthesis .…”

Section: Introductionmentioning

confidence: 99%

“…2−6 It has been suggested that a strong van der Waals interaction of the guest molecule with the framework within the zeolite structure can be responsible for some selectivity in synthesis and subsequent stabilization (either thermodynamic or kinetic) of that product against the further cascade of reaction toward higher framework density. [7][8][9][10]27 Zeolite synthesis starts in aqueous solution with the condensation of dissolved silicate species interacting with a dissolved organic molecule, the so-called structure-directing agent (SDA), leading to crystallization of a microporous product in which the SDA is contained in the zeolite cages. Thus, the transfer of the SDA, generally a fairly hydrophobic molecule, from the hydrophilic environment of the aqueous phase to the much less hydrophilic environment of the zeolitic pore, occurs during synthesis.…”

Section: ■ Introductionmentioning

confidence: 99%

Energetics of the Local Environment of Structure-Directing Agents Influence Zeolite Synthesis

et al. 2021

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Organic structure-directing agents (SDAs) play a crucial role in the synthesis of zeolites like SSZ-13 (CHA structure), with novel frameworks and compositions. Zeolite crystallization is aided by the removal of the hydrophobic SDA organocations from an aqueous environment and their incorporation into an emerging silicate framework. This study combined several experimental approaches to understand the influence on nucleation to form SSZ-13 as the size of the SDA was changed. We studied crystallization rates, then modeled the SDA fit in the product to look at correlations for the rates, and then performed the measurement of SDA zeolite filling in the products. Then, we moved to determine the driving force for the transfer of this same series of organic SDAs, (C/N + = 7−16) from water to chloroform, the latter a proxy for a much less hydrophilic zeolitic environment. Calorimetric measurements of dissolution enthalpy for each SDA in water and chloroform provided enthalpy data and the distribution coefficients for the transfer reaction were measured, both at room temperature. From these experiments, the corresponding transfer enthalpy, entropy, and free energy were calculated. The thermodynamic parameters of the transfer process depend on the C/N + ratio, location, and environment of the charge in the SDA structure and are a good measure of the ability of the SDA to make the target zeolite, SSZ-13 (CHA). However, the use of a particular, hydrophilic SDA as a counter-example in this particular zeolite synthesis also produced rapid crystallization rates and demonstrated that the opportunity to initiate nucleation, by virtue of docking of the SDA coupled with best SDA-fit, may provide the optimum use of the SDA, providing a stronger factor than the solution transfer thermodynamics.

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“…This topic has received much attention over the past two decades. Three-dimensional zeolites for which a layered precursor has been identified include materials with AST, CAS, CDO, FER, MTF, MWW, NSI, PCR, RRO, RWR and SOD topologies as well as zeolite SSZ-81 with an unknown structure. − The layered zeolite precursors are typically obtained as products from hydrothermal synthesis. However, 3D zeolites can also be transformed into a 2D layered zeolite precursor.…”

Section: Introductionmentioning

confidence: 99%

From Layered Zeolite Precursors to Zeolites with a Three-Dimensional Porosity: Textural and Structural Modifications through Alkaline Treatment

et al. 2014

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The layered zeolite precursor RUB-36, consisting of ferrierite-type layers, can be transformed into a threedimensional framework through various methods such as topotactic condensation into the CDO topology, or interlayer expansion either in the presence or absence of a silylating agent. However, the plate-like morphology of the micrometer sized crystals hampers the accessibility of the 2D micropore system, in which the channels run parallel to the plates. With the aim of introducing mesoporosity, alkaline treatments were performed on different RUB-36 derived expanded materials, and on RUB-36 itself. The effect on the physicochemical properties was examined using N 2 physisorption, PXRD, SEM and 27 Al MAS NMR while the influence on the catalytic activity was evaluated using esterification and alkylation reactions. After calcination, the purely inorganic, interlayer expanded material could be transformed into a mesopore containing FER-type material by selective removal of the interlayer T-atom followed by the recombination of the layers. In the pre-calcination state, organic moieties -originating from the silylating agent or from the organic structure directing agent (OSDA) -increase the hydrophobicity of the interlayer expanded structure and its stability against the alkaline treatment. In RUB-36, the high OSDA content limited the amount of mesopore formation through alkaline treatment. However, using the appropriate conditions, the subsequent interlayer expansion of alkaline treated RUB-36 also resulted in a mesopore containing interlayer expanded structure.

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A hydrothermal synthesis of a 2-dimensional layered silicate followed by a transition to a 3-dimensional aluminosilicate zeolite

Cited by 7 publications

References 32 publications

Synthesis of Germanosilicate Molecular Sieves from Mono- and Di-Quaternary Ammonium OSDAs Constructed from Benzyl Imidazolium Derivatives: Stabilization of Large Micropore Volumes Including New Molecular Sieve CIT-13

Synthesis of Germanosilicate Molecular Sieves from Mono- and Di-Quaternary Ammonium OSDAs Constructed from Benzyl Imidazolium Derivatives: Stabilization of Large Micropore Volumes Including New Molecular Sieve CIT-13

Energetics of the Local Environment of Structure-Directing Agents Influence Zeolite Synthesis

From Layered Zeolite Precursors to Zeolites with a Three-Dimensional Porosity: Textural and Structural Modifications through Alkaline Treatment

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