Microwave Hydrothermal Synthesis of Bimetallic (Ti-V) Ions Modified MCM-41 for Epoxidation of Styrene

2010 ◽  
Vol 1279 ◽  
Author(s):  
Yajie Guo ◽  
Guangjian Wang ◽  
Yuran Wang ◽  
Zhengwang Li ◽  
Guangqing Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Synthesis ◽  
Molecular Sieves ◽  
Magic Angle Spinning ◽  
Mesoporous Molecular Sieves ◽  
Magic Angle ◽  
X Ray ◽  
Microwave Hydrothermal ◽  
Hexagonal Arrangement ◽  
Mcm 41

AbstractMesoporous molecular sieves MCM-41 modified by single (Ti) and bimetal (Ti-V) ions with highly ordered hexagonal arrangement of their cylindrical channels were prepared by direct synthesis under microwave–hydrothermal (M–H) conditions at 403K. Characterizations with powder X-ray diffraction (XRD), 29Si magic-angle spinning (MAS) NMR, N2 adsorption–desorption, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray photoelcctron spectra(XPS) and transmission electron microscopy (TEM) showed that Ti and V ions were introduced into MCM-41 under M-H conditions and Ti/V-Si bond was formed. Results revealed that all the samples were of a typical hexagonal arrangement of mesoporous structure. The modified materials were high active and selective in the epoxidation of styrene at 343 K in comparison with single-functional MCM-41. Moreover, compared to conventional method, the presented microwave hydrothermal synthesis of molecular sieves greatly improved the selectivity to styrene oxide, e.g., it reached 58.6% at styrene conversion of 18.7% over Ti-V-MCM-41 (50).

Ti incorporation in MCM-41 mesoporous molecular sieves using hydrothermal synthesis

2014 ◽  
Vol 8 (1) ◽  
pp. 95-103 ◽  
Author(s):  
Shengping Wang ◽  
Changqing Ma ◽  
Yun Shi ◽  
Xinbin Ma
Keyword(s):  
Hydrothermal Synthesis ◽  
Molecular Sieves ◽  
Mesoporous Molecular Sieves ◽  
Mcm 41

Adsorption of Carbon Dioxide into Amine Functionalized Ordered Mesoporous Materials

2018 ◽  
Author(s):  
Marcela N. Barbosa ◽  
Maria J. F. Costa ◽  
Maricele N. Barbosa ◽  
Valter J. Fernandes Jr. ◽  
Giancarlo R. Salazar-Banda ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Adsorption Capacity ◽  
Photoelectron Spectroscopy ◽  
Molecular Sieves ◽  
Synthesis Method ◽  
Mesoporous Molecular Sieves ◽  
Carbon Dioxide Adsorption ◽  
X Ray ◽  
Ordered Mesoporous ◽  
Mcm 41

The adsorption of carbon dioxide on amino silanes-functionalized MCM-41 and SBA-15 materials is reported. The functionalization of mesoporous silicas was made by post-synthesis method, by impregnation of 3-aminopropyltriethoxysilane. The obtained materials were characterized by X-ray diffraction, scanning and transmission electron microscopies, nitrogen adsorption-desorption and X-ray photoelectron spectroscopy measurements. The carbon dioxide adsorption capacities for the samples were carried out under ambient pressures. The obtained results evidenced that amino-silanes with a terminal amine (–NH2) were functionalized through covalent coupling of this group on the surface of the channels in the ordered mesoporous silica, meaning that the amine is anchored on the surface of the bigger pores of the MCM-41 and SBA-15 support. For functionalized materials, the CO2 adsorption capacity of the AMCM-41 increased from 0.18 to 1.1 mmol·g−1, whereas for ASBA-15, it was from 0.6 to 1.8 mmol·g−1. The Lagergren kinetic algorithms were applied in order to validate the obtained results, evidencing the enhanced carbon dioxide adsorption capacity and stability of the functionalized ordered mesoporous molecular sieves.

scholarly journals SYSU-6, A New 2-D Aluminophosphate Zeolite Layer Precursor

Molecules ◽  
2019 ◽  
Vol 24 (16) ◽  
pp. 2972 ◽  
Author(s):  
Jiang-Zhen Qiu ◽  
Long-Fei Wang ◽  
Jiuxing Jiang
Keyword(s):  
Electron Microscopy ◽  
Single Crystal ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
X Ray Diffraction ◽  
Structure Directing Agent ◽  
X Ray ◽  
Uv Raman ◽  
Angle Spinning ◽  
Inorganic Framework

Two-dimensional aluminophosphate is an important precursor of phosphate-based zeolites; a new Sun Yat-sen University No. 6 (SYSU-6) with |Hada|2[Al2(HPO4)(PO4)2] has been synthesized in the hydrothermal synthesis with organic structure-directing agent (OSDA) of N,N,3,5-tetramethyladamantan-1-amine. In this paper, SYSU-6 is characterized by single-crystal/powder X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, transmission electron microscopy, infrared and UV Raman spectroscopy, solid-state 27Al, 31P and 13C magic angle spinning (MAS) NMR spectra, and elemental analysis. The single-crystal X-ray diffraction structure indicates that SYSU-6 crystallized in the space group P21/n, with a = 8.4119(3), b = 36.9876(12), c = 12.5674(3), α = 90°, β = 108.6770(10)°, γ = 90°, V = 3704.3(2) Å3, Z = 4, R = 5.12%, for 8515 observed data (I > 2σ(I)). The structure has a new 4,12-ring layer framework topology linked by alternating AlO4 and PO4 tetrahedra. The organic molecules reside between the layers and are hydrogen-bonded to the inorganic framework. The new type of layer provides a greater opportunity to construct zeolite with novel topology.

scholarly journals Microwave Hydrothermal Synthesis and Acidity of Nanosize Gallosilicate Mesoporous Molecular Sieves

2011 ◽  
Vol 58 (2) ◽  
pp. 155-162
Author(s):  
Chi-Feng Cheng ◽  
Shih-Miao Liu ◽  
Hsu-Hsuan Cheng ◽  
Marina G. Yao ◽  
Shang Bin Liu
Keyword(s):  
Hydrothermal Synthesis ◽  
Molecular Sieves ◽  
Mesoporous Molecular Sieves ◽  
Microwave Hydrothermal

scholarly journals Pt Modified Heterogeneous Catalysts Combined with Ozonation for the Removal of Diclofenac from Aqueous Solutions and the Fate of by-Products

Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 322 ◽  
Author(s):  
Soudabeh Saeid ◽  
Matilda Kråkström ◽  
Pasi Tolvanen ◽  
Narendra Kumar ◽  
Kari Eränen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Molecular Sieves ◽  
Heterogeneous Catalysts ◽  
Maximum Activity ◽  
Mesoporous Molecular Sieves ◽  
Emission Spectrometry ◽  
Characterization Methods ◽  
X Ray ◽  
By Products

The degradation of the pharmaceutical compound diclofenac in an aqueous solution was studied with an advanced oxidation method, catalytic ozonation. Diclofenac was destroyed in a few minutes by ozonation but several long-lasting degradation by-products were formed. For this reason, the combination of heterogeneous catalysts and ozonation was applied to eliminate them completely. The kinetics of the diclofenac degradation and the formation of by-products were thoroughly investigated. Loading of Pt on the catalysts resulted in an improvement of the activity. The Mesoporous Molecular Sieves (MCM) were one of the promising catalysts for the degradation of organic pollutants. In this study, six heterogeneous catalysts were screened, primarily MCM-22-100 catalysts with different Pt concentrations loaded via the evaporation-impregnation (EIM) method, and they were applied on the degradation of diclofenac. It was found that the presence of Pt improved the degradation of diclofenac and gave lower concentrations of by-products. The 2 wt % Pt-H-MCM-22-100-EIM demonstrated the highest degradation rate compared to the proton form, 1% or 5 wt % Pt concentration, i.e., an optimum was found in between. Pt-H-Y-12-IE and Pt-γ-Al2O3 (UOP)-IMP catalysts were applied and compared with the MCM-22 structure. Upon use of both of these catalysts, an improvement in the degradation of diclofenac and by-products was observed, and the 2 wt % Pt-H-MCM-22-100-EIM illustrated the maximum activity. All important characterization methods were applied to understand the behavior of the catalysts (X-ray powder diffraction, transmission electron microscopy, nitrogen physisorption, scanning electron microscopy, energy dispersive X-ray micro-analyses, pyridine adsorption-desorption with FTIR spectroscopy, X-ray photoelectron spectroscopy). Finally, leaching of Pt and Al were analyzed by inductively coupled optical emission spectrometry.

Alkylation of p-Cresol with Isobutylene Catalyzed by Heteropoly Acid Supported on MCM-41 Catalyst

2011 ◽  
Vol 356-360 ◽  
pp. 2803-2807 ◽  
Author(s):  
Zai Man Liu ◽  
Pei Pei Deng ◽  
Bai Yu Li
Keyword(s):  
Molecular Sieves ◽  
Heteropoly Acid ◽  
Mesoporous Molecular Sieves ◽  
Reaction Parameters ◽  
Reaction Conditions ◽  
Wet Impregnation ◽  
X Ray ◽  
Tert Butyl ◽  
Temperature Time ◽  
Mcm 41

The phosphorus tungsten(PW) heteropoly acids were immobilized on the mesoporous molecular sieves(MCM-41) by wet impregnation. The prepared catalysts were characterized by X-ray powder diffraction, TG and DTA,FTIR. The alkylation of p-cresol with isobutylene was carried out over the PW /MCM-41 catalysts. The influences of various reaction parameters such as reaction temperature, time, PW loading, and catalysts amount on the conversion of p-cresol and the products selectivity were also investigated. Under the optimized reaction conditions of 90 °C,PW loading of 10%, catalyst amount of 1.5%, p-cresol conversion was found to be 93.89% with product rate to 2-tert-butyl-p-cresol 51.29%, 2,6-di-tert-butyl-p-cresol 42.48% and tert-butyl-p-tolyl ether 0.12%, responding to selectivity of 2, 6-di-tert-butyl-p-cresol 45.24%.

Microwave hydrothermal synthesis and catalytic cracking of polyethylene of microporous-mesoporous molecular sieves (HY/SBA-15)

2020 ◽  
Vol 258 ◽  
pp. 126805 ◽  
Author(s):  
Chunwei Shi ◽  
Yang Fu ◽  
Wenyi Chen ◽  
Honglei Shi ◽  
Yufeng Cong ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Molecular Sieves ◽  
Catalytic Cracking ◽  
Mesoporous Molecular Sieves ◽  
Microwave Hydrothermal

scholarly journals Adsorption of Carbon Dioxide into Amine Functionalized Ordered Mesoporous Materials

2018 ◽  
Author(s):  
Marcela N. Barbosa ◽  
Maria J. F. Costa ◽  
Maricele N. Barbosa ◽  
Valter J. Fernandes Jr. ◽  
Giancarlo R. Salazar-Banda ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Adsorption Capacity ◽  
Photoelectron Spectroscopy ◽  
Molecular Sieves ◽  
Synthesis Method ◽  
Mesoporous Molecular Sieves ◽  
Carbon Dioxide Adsorption ◽  
X Ray ◽  
Ordered Mesoporous ◽  
Mcm 41

The adsorption of carbon dioxide on amino silanes-functionalized MCM-41 and SBA-15 materiais is reported. The functionalization of mesoporous silicas was made by post-synthesis method, by impregnation of 3-aminopropyltriethoxysilane. The obtained materials were characterized by X-ray diffraction, scanning and transmission electron microscopies, nitrogen adsorption-desorption and X-ray photoelectron spectroscopy measurements. The carbon dioxide adsorption capacities for the samples were carried out under ambient pressures. The obtained results evidenced that amino-silanes with a terminal amine (–NH2) were functionalized through covalent coupling of this group on the surface of the channels in the ordered mesoporous silica, meaning that the amine is anchored on the surface of the bigger pores of the MCM-41 and SBA-15 support. For functionalized materials, the CO2 adsorption capacity of the AMCM-41 increased from 0.18 to 1.1 mmol g−1, whereas for ASBA-15, it was from 0.6 to 1.8 mmol g−1. The Lagergren kinetic algorithms were applied in order to validate the obtained results, evidencing the enhanced carbon dioxide adsorption capacity and stability of the functionalized ordered mesoporous molecular sieves.

scholarly journals Hydrothermal Synthesis, Characterization and Exploration of Photocatalytic Activities of Polyoxometalate: Ni-CoWO4 Nanoparticles

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 456
Author(s):  
Fahad A. Alharthi ◽  
Hamdah S. Alanazi ◽  
Amjad Abdullah Alsyahi ◽  
Naushad Ahmad
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Synthesis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Structure Morphology ◽  
Photocatalytic Activities ◽  
Ft Ir ◽  
Photocatalytic Reactions ◽  
Cobalt Tungstate

This study demonstrated the hydrothermal synthesis of bimetallic nickel-cobalt tungstate nanostructures, Ni-CoWO4 (NCW-NPs), and their phase structure, morphology, porosity, and optical properties were examined using X-ray Diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Scanning electron microscopy- energy dispersive X-ray spectroscopy (SEM-EDS), high resolution Transmission electron microscopy (HR-TEM), Brunauer-Emmett-Teller (BET) and Raman instruments. It was found that as-calcined NCW-NPs have a monoclinic phase with crystal size ~50–60 nm and is mesoporous. It possessed smooth, spherical, and cubic shape microstructures with defined fringe distance (~0.342 nm). The photocatalytic degradation of methylene blue (MB) and rose bengal (RB) dye in the presence of NCW-NPs was evaluated, and about 49.85% of MB in 150 min and 92.28% of RB in 90 min degraded under visible light. In addition, based on the scavenger’s study, the mechanism for photocatalytic reactions is proposed.

A 13C and 15N nuclear magnetic resonance study of solid ammonium thiocyanate

1987 ◽  
Vol 65 (5) ◽  
pp. 941-946 ◽  
Author(s):  
Ross M. Dickson ◽  
Michael S. McKinnon ◽  
James F. Britten ◽  
Roderick E. Wasylishen
Keyword(s):  
Ammonium Thiocyanate ◽  
Nuclear Magnetic Resonance Study ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Chemical Shielding ◽  
X Ray ◽  
Shielding Constants ◽  
Angle Spinning ◽  
Good Agreement ◽  
C Nmr

The static 13C nmr powder pattern for solid ammonium thiocyanate is analyzed to obtain the 13C chemical shielding anisotropy, 321 ± 7 ppm, and the 13C–14N dipolar splitting, 1295 ± 25 Hz. Slow magic angle spinning 15N nmr experiments are analyzed to obtain a nitrogen chemical shielding anisotropy of 415 ± 15 ppm. The 13C–14N dipolar splitting leads to an effective C—N bond length of 1.19 ± 0.01 Å, in good agreement with the value of 1.176 Å reported from accurate X-ray and neutron crystallographic studies. In solid NH4NCS absolute values of the average shielding constants [Formula: see text] and ct[Formula: see text] are 52 and 34 ppm, respectively. Comparison of calculated and observed [Formula: see text] values indicates that intermolecular interactions decrease the 13C and 15N shielding constants by approximately 10 and 30 ppm, respectively.

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