Browse
Submit Data
Databases
API
Help

Dataset Information

15 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Structure Elucidation and Computationally Guided Synthesis of SSZ-43: A One-Dimensional 12-Ring Zeolite with Unique Sinusoidal Channels.

ABSTRACT: The structure of zeolite SSZ-43 was determined by 3D electron diffraction, synchrotron X-ray powder diffraction, and high-resolution transmission electron microscopy. The SSZ-43 framework forms one-dimensional, sinusoidal 12-ring channels from 5⁴ 6¹ butterfly units commonly found in other zeolites, but with unique 6.5×6.5 Å apertures and 12-ring 6.5×8.9 Å windows perpendicular to the channels. SSZ-43 crystals are intergrowths of two polytypes: ≈90 % orthorhombic polytype A with ABAB stacking of the 12-rings, and ≈10 % monoclinic polytype B with ABCABC stacking. Molecular modeling performed on the idealized Si-SSZ-43 structure along with empirical relationships for zeolite selectivity in boron- and aluminum-containing synthesis gels were used in a combined approach to design new di-quaternary ammonium organic structure-directing agents (OSDAs). Experimental trials demonstrated that the new OSDAs produced SSZ-43 over a broader range of compositions than previous mono-quaternary OSDAs.

SUBMITTER: Roslova M

PROVIDER: S-EPMC9306729 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

ITQ-54: a multi-dimensional extra-large pore zeolite with 20 × 14 × 12-ring channels.

Project description:A multi-dimensional extra-large pore silicogermanate zeolite, named ITQ-54, has been synthesised by in situ decomposition of the N,N-dicyclohexylisoindolinium cation into the N-cyclohexylisoindolinium cation. Its structure was solved by 3D rotation electron diffraction (RED) from crystals of ca. 1 ?m in size. The structure of ITQ-54 contains straight intersecting 20 × 14 × 12-ring channels along the three crystallographic axes and it is one of the few zeolites with extra-large channels in more than one direction. ITQ-54 has a framework density of 11.1 T atoms per 1000 Å3, which is one of the lowest among the known zeolites. ITQ-54 was obtained together with GeO2 as an impurity. A heavy liquid separation method was developed and successfully applied to remove this impurity from the zeolite. ITQ-54 is stable up to 600 °C and exhibits permanent porosity. The structure was further refined using powder X-ray diffraction (PXRD) data for both as-made and calcined samples.

| S-EPMC5811170 | biostudies-literature

A multi-dimensional quasi-zeolite with 12 × 10 × 7-ring channels demonstrates high thermal stability and good gas adsorption selectivity.

Project description:A novel quasi-zeolite PKU-15, with a rare 3-dimensional structure containing interconnected large (12-ring), medium (10-ring) and small (7-ring) multi-pore channels, was hydrothermally synthesised and characterised. A unique tri-bridging O2- anion is found to be encapsulated in the cage-like (Ge,Si)12O31 building unit and energetically stabilises the PKU-15 framework. The removal of this oxygen atom would convert PKU-15 into a hypothetical zeolite PKU-15H. Thus, PKU-15 can be considered as a unique 'quasi-zeolite', which bridges porous germanates and zeolites. Owing to the absence of terminal Ge-OH groups in its structure, PKU-15 shows a remarkably high thermal stability of up to 600 °C. PKU-15 is also the first microporous germanate that exhibits permanent porosity, with a BET area of 428 m2 g-1 and a good adsorption affinity toward CO2.

| S-EPMC6005135 | biostudies-literature

A Stable Silanol Triad in the Zeolite Catalyst SSZ-70.

Project description:Nests of three silanol groups are located on the internal pore surface of calcined zeolite SSZ-70. 2D 1 H double/triple-quantum single-quantum correlation NMR experiments enable a rigorous identification of these silanol triad nests. They reveal a close proximity to the structure directing agent (SDA), that is, N,N'-diisobutyl imidazolium cations, in the as-synthesized material, in which the defects are negatively charged (silanol dyad plus one charged SiO- siloxy group) for charge balance. It is inferred that ring strain prevents the condensation of silanol groups upon calcination and removal of the SDA to avoid energetically unfavorable three-rings. In contrast, tetrad nests, created by boron extraction from B-SSZ-70 at various other locations, are not stable and silanol condensation occurs. Infrared spectroscopic investigations of adsorbed pyridine indicate an enhanced acidity of the silanol triads, suggesting important implications in catalysis.

| S-EPMC7317713 | biostudies-literature

ADOR zeolite with 12 × 8 × 8-ring pores derived from IWR germanosilicate.

Project description:Zeolites have been well known for decades as catalytic materials and adsorbents and are traditionally prepared using the bottom-up synthesis method. Although it was productive for more than 250 zeolite frameworks, the conventional solvothermal synthesis approach provided limited control over the structural characteristics of the formed materials. In turn, the discovery and development of the Assembly-Disassembly-Organization-Reassembly (ADOR) strategy for the regioselective manipulation of germanosilicates enabled the synthesis of previously unattainable zeolites with predefined structures. To date, the family tree of ADOR materials has included the topological branches of UTL, UOV, IWW, *CTH, and IWV zeolites. Herein, we report on the expansion of ADOR zeolites with a new branch related to the IWR topology, which is yet unattainable experimentally but theoretically predicted as highly promising adsorbents for CO2 separation applications. The optimization of not only the chemical composition but also the dimensions of the crystalline domain in the parent IWR zeolite in the Assembly step was found to be the key to the success of its ADOR transformation into previously unknown IPC-17 zeolite with an intersecting 12 × 8 × 8-ring pore system. The structure of the as-prepared IPC-17 zeolite was verified by a combination of microscopic and diffraction techniques, while the results on the epichlorohydrin ring-opening with alcohols of variable sizes proved the molecular sieving ability of IPC-17 with potential application in heterogeneous catalysis. The proposed synthesis strategy may facilitate the discovery of zeolite materials that are difficult or yet impossible to achieve using a traditional bottom-up synthesis approach.

| S-EPMC10763919 | biostudies-literature

Hydrogen Bonds Dominate Bronsted Acid Sites in Zeolite SSZ-42: A Classification of Their Diversity.

Project description:The zeolite catalyst SSZ-42 shows a remarkable high abundance (≈80 %) of hydrogen-bonded Brønsted acid sites (BAS), which are deshielded from the 1 H chemical shift of unperturbed BAS at typically 4 ppm. This is due to their interaction with neighboring oxygen atoms in the zeolite framework when oxygen alignments are suitable. The classification and diversity of hydrogen bonding is assessed by DFT calculations, showing that oval-shaped 6-rings and 5-rings allow for a stronger hydrogen bond to oxygen atoms on the opposite ring side, yielding higher experimental chemical shifts (δ (1 H)=6.4 ppm), than circular 6-rings (δ(1 H)=5.2 ppm). Cage-like structures and intra-tetrahedral interactions can also form hydrogen bonds. The alignment of oxygen atoms is expected to impact their role in the stabilization of intermediates in catalytic reactions, such as surface alkoxy groups and possibly transition states.

| S-EPMC9299800 | biostudies-literature

Evaluation of Co/SSZ-13 Zeolite Catalysts Prepared by Solid-Phase Reaction for NO-SCR by Methane.

Project description:Co/SSZ-13 zeolites were prepared by heating the finely dispersed mixture of NH4-SSZ-13 and different cobalt salts up to 550 °C. Investigations by thermogravimetry - differential scanning calorimetry - mass spectrometry provided new insight into details of the solid-state reaction. Formation of Co carrying hydrate melt or volatile species was shown to proceed from chloride, nitrate, or acetylacetonate Co precursor salts upon thermal treatment. This phase change allows the transport of the Co species into the zeolite pores. The reaction of the NH4+ or H+ zeolite cations and the mobile Co precursors generates vapor or gas products, readily leaving the zeolite pores, and cobalt ions in lattice positions suggesting that solid-state ion-exchange is the prevailing process. The obtained catalysts are of good activity and N2 selectivity in the CH4/NO-SCR reaction. The thermal treatment of acetate or formate salts give solid intermediates that are unable to get in contact and react with the cations in the zeolite micropores. These catalysts contain mainly Co-oxide clusters located on the outer surface of the zeolite crystallites and have poor catalytic performance.

| S-EPMC7645688 | biostudies-literature

Confined Cu-OH single sites in SSZ-13 zeolite for the direct oxidation of methane to methanol.

Project description:The direct oxidation of methane to methanol (MTM) remains a significant challenge in heterogeneous catalysis due to the high dissociation energy of the C-H bond in methane and the high desorption energy of methanol. In this work, we demonstrate a breakthrough in selective MTM by achieving a high methanol space-time yield of 2678 mmol molCu-1 h-1 with 93% selectivity in a continuous methane-steam reaction at 400 °C. The superior performance is attributed to the confinement effect of 6-membered ring (6MR) voids in SSZ-13 zeolite, which host isolated Cu-OH single sites. Our results provide a deeper understanding of the role of Cu-zeolites in continuous methane-steam to methanol conversion and pave the way for further improvement.

| S-EPMC10673993 | biostudies-literature

SSZ-27: A Small-Pore Zeolite with Large Heart-Shaped Cavities Determined by Using Multi-crystal Electron Diffraction.

Project description:The high-silica zeolite SSZ-27 was synthesized using one of the isomers of the organic structure-directing agent that is known to produce the large-pore zeolite SSZ-26 (CON). The structure of the as-synthesized form was solved using multi-crystal electron diffraction data. Data were collected on eighteen crystals, and to obtain a high-quality and complete data set for structure refinement, hierarchical cluster analysis was employed to select the data sets most suitable for merging. The framework structure of SSZ-27 can be described as a combination of two types of cavities, one of which is shaped like a heart. The cavities are connected through shared 8-ring windows to create straight channels that are linked together in pairs to form a one-dimensional channel system. Once the framework structure was known, molecular modelling was used to find the best fitting isomer, and this, in turn, was isolated to improve the synthesis conditions for SSZ-27.

| S-EPMC6773097 | biostudies-literature

zeolite

Project description:Generic role of zeolite in enhancing anaerobic digestion and mitigating diverse inhibitions: insights from degradation performance and microbial characteristics

| PRJEB65129 | ENA

Computationally Assisted Structural Elucidation of Cembranoids from the Soft Coral <i>Sarcophyton tortuosum</i>.

Project description:A persistent study on soft coral Sarcophyton tortuosum resulted in the characterization of two new cembranolides, tortuolides A and B (1 and 2), and a new related diterpene, epi-sarcophytonolide Q. Their structures were determined not only by extensive spectroscopic analysis but also by DFT calculations of ECD and NMR data, the latter of which was combined with statistical analysis methods, e.g., DP4+ and J-DP4 approaches. Anti-inflammatory and cytotoxicity activities were evaluated in this study.

| S-EPMC9147035 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data