scholarly journals Hydrodemethoxylation/Dealkylation on Bifunctional Nanosized Zeolite Beta

Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7694
Author(s):  
Margarita Popova ◽  
Ágnes Szegedi ◽  
Manuela Oykova ◽  
Hristina Lazarova ◽  
Neli Koseva ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Structural Changes ◽  
Synthesis Method ◽  
Ruthenium Oxide ◽  
Acid Sites ◽  
Zeolite Catalysts ◽  
Beta Zeolite ◽  
Nickel Ions ◽  
Ft Ir

Mono-, and bimetallic Ni-, Ru-, and Pt-modified nanosized Beta zeolite catalysts were prepared by the post synthesis method and characterized by powder X-ray diffraction (XRD), nitrogen physisorption, HRTEM microscopy, temperature-programmed reduction (TPR-TGA), ATR FT-IR spectroscopy, and by solid-state MAS-NMR spectroscopy. The presence of nanosized nickel-oxide, ruthenium-oxide, and platinum species was detected on the catalysts. The presence of Brønsted and Lewis acid sites, and incorporation of nickel ions into zeolite lattice was proven by FT-IR of adsorbed pyridine. The structural changes in the catalyst matrix were investigated by solid state NMR spectroscopy. The catalysts were used in a gas-phase hydrodemethoxylation and dealkylation of 2-methoxy-4-propylphenol as a lignin derivative molecule for phenol synthesis.

Unravelling the dissolution mechanism of polyphosphate glasses by 31P NMR spectroscopy: ligand competition and reactivity of intermediate complexes

2021 ◽  
Author(s):  
Dahiana Andrea Avila Salazar ◽  
Peter Bellstedt ◽  
Atsuhiro Miura ◽  
Yuki Oi ◽  
Toshihiro Kasuga ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Solid State ◽  
Nmr Spectroscopy ◽  
Biomedical Applications ◽  
Structural Changes ◽  
31P Nmr ◽  
Dissolution Mechanism ◽  
31P Nmr Spectroscopy ◽  
Glass Dissolution ◽  
Polyphosphate Glasses

Phosphate glass dissolution can be tailored via compositional and subsequent structural changes, which is of interest for biomedical applications such as therapeutic ion delivery. Here, solid-state 31P nuclear magnetic resonance...

scholarly journals The acidic nature of “NMR-invisible” tri-coordinated framework aluminum species in zeolites

2019 ◽  
Vol 10 (43) ◽  
pp. 10159-10169 ◽  
Author(s):  
Shaohui Xin ◽  
Qiang Wang ◽  
Jun Xu ◽  
Yueying Chu ◽  
Pengfei Wang ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Solid State Nmr ◽  
Zeolite Catalysts ◽  
Probe Molecules ◽  
Solid State Nmr Spectroscopy ◽  
Acidic Nature ◽  
Insight Into

A unique insight into the acidic nature of the tri-coordinated framework aluminum (AlFR) in H-ZSM-5 zeolite catalysts has been provided using multi-nuclear and multi-dimensional solid-state NMR spectroscopy in conjunction with TMPO probe molecules.

A Novel Iron Silicate Mesoporous Material Synthesis and Its Characterization

2018 ◽  
Vol 24 (8) ◽  
pp. 5532-5536
Author(s):  
M. A Mary Thangam ◽  
Chellapandian Kannan
Keyword(s):  
Mesoporous Materials ◽  
Molecular Sieves ◽  
Mesoporous Material ◽  
Synthesis Method ◽  
Acid Sites ◽  
Mesoporous Molecular Sieves ◽  
Isomorphous Substitution ◽  
Main Role ◽  
Material Synthesis ◽  
Ft Ir

The mesoporous materials have variety of applications in several field particularly it has a main role in Catalysis, Petrochemical industries and Adsorption. Normally the porous material has well ordered 3Dimensional structure, huge surface area, high thermal stability and active acid sites. The properties of these materials can be varied because it is mostly depends on its template, synthesis method and isomorphous substitution of metal ions. There are two major mesoporous materials which are aluminosilicate and aluminophosphate. In this present investigation AlCl3 and FeCl3 are used in equal amount for the synthesis of mesoporous material. The synthesized material is characterized by FT-IR, XRD, TGA, BET, EDAX and TPD. Morphological images were studied by SEM. These characterization techniques confirm the formation of mesoporous molecular sieves.

scholarly journals Observation of Multinuclear Extra-framework Aluminum Species in Dealuminated Zeolite Catalysts

2020 ◽  
Author(s):  
Anmin Zheng ◽  
Xianfeng Yi ◽  
Yao Xiao ◽  
Zhiqiang Liu ◽  
Guangchao Li ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Zeolite Catalysts ◽  
Two Dimensional ◽  
Thermal Stabilities ◽  
Acidic Sites ◽  
Transformation Mechanisms ◽  
First Time ◽  
Intense Debate ◽  
Catalytic Performances

Abstract Although the Lewis acidic extra-framework aluminum (EFAL) species usually play decisive roles in improving the thermal stabilities, acidity and catalytic performances of industrialized zeolitic catalysts, the structure of these important EFAL clusters has long been a subject of intense debate, and their characterization remains a challenging task. Particularly, the more stable and even more catalytic active multinuclear EFAL clusters have never been experimentally observed owing to the nearly indistinguishable physicochemical properties of mononuclear and multinuclear EFAL species detected by conventional techniques. Herein, by invoking advanced two-dimensional (2D) solid-state 31P NMR spectroscopy in conjunction with a novel probe molecule, namely 1,2-bis(dimethylphosphine) ethane (DMPE), we demonstrated for the first time that the presence of multinuclear EFAL species in dealuminated zeolites. Furthermore, based on the comprehensive spatial interactions information from 2D 31P-31P homonuclear correlation NMR experiments, the evolution and transformation mechanisms of various acidic sites during the dealumination treatment of zeolites have also been clarified.

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