Acidic Properties and Catalytic Activities of Sol–gel Derived Zn2SiO4

2004 ◽  
Vol 33 (5) ◽  
pp. 566-567
Author(s):  
Yoritsugu Shino ◽  
Hirotoshi Nakabayashi
Keyword(s):  
Sol Gel ◽  
Acidic Properties ◽  
Catalytic Activities

Sol-Gel Synthesis and Characterisation of Nanoscopic FeF3-MgF2Heterogeneous Catalysts with Bi-Acidic Properties

ChemCatChem ◽  
2013 ◽  
Vol 5 (8) ◽  
pp. 2223-2232 ◽  
Author(s):  
Ying Guo ◽  
Piotr Gaczyński ◽  
Klaus-Dieter Becker ◽  
Erhard Kemnitz
Keyword(s):  
Sol Gel ◽  
Acidic Properties ◽  
Sol Gel Synthesis

Crystalline and amorphous aluminosilicates with different pore structures for the synthesis of pyridines

2017 ◽  
Vol 41 (5) ◽  
pp. 253-261 ◽  
Author(s):  
Nellya G. Grigor'eva ◽  
Nadezhda A. Filippova ◽  
Marat R. Agliullin ◽  
Boris I. Kutepov ◽  
Nama Narender
Keyword(s):  
Sol Gel ◽  
Catalytic Synthesis ◽  
Maximum Amount ◽  
Macroporous Structure ◽  
Acidic Properties ◽  
Mesoporous Aluminosilicates ◽  
Zeolite Framework ◽  
Narrow Pore Size Distribution ◽  
Heterogeneous Catalytic ◽  
Sol Gel Synthesis

The heterogeneous catalytic synthesis of pyridine and methylpyridines (picolines) was carried out by the reaction of ethanol with formaldehyde and ammonia over aluminosilicates with different acidic properties and textural characteristics: zeolite framework-type FAU in H-form with microporous (H-Y) and micro-meso-macroporous structure (H-Y-mmm) and mesoporous aluminosilicates, obtained by sol-gel synthesis in an alkaline medium (ASM-1) and under variable pH (ASM-2). It is shown that the highest catalytic activity is characteristic of ASM-2 (Si/Al = 40) with a narrow pore size distribution within the range 2 to 5 nm and containing strongly acidic bridging Si–OH–Al groups on the surface. The products of the reaction of ethanol with formaldehyde and ammonia on the catalysts studied are dominated by picolines; the maximum amount of picolines (60%) is formed on the H-Y-mmm and aluminosilicate ASM-2 samples.

Preparation and Photocatalytic Properties of Fe-Doped TiO2 Nanocrystalline Composite Particles

2010 ◽  
Vol 105-106 ◽  
pp. 815-818
Author(s):  
Hai Da Liao ◽  
Jin Lie Ma ◽  
Jian Dai
Keyword(s):  
Suspension Polymerization ◽  
Sol Gel ◽  
Average Particle Size ◽  
Raw Material ◽  
Composite Particles ◽  
Average Particle ◽  
Doped Tio2 ◽  
Catalytic Activities ◽  
Metatitanic Acid ◽  
Nanocrystalline Composite

Metatitanic acid was adopted as the raw material to prepare Fe-doped TiO2 nanocrystalline composite particles using suspension polymerization and sol-gel method, which were then characterized with XRD, TEM, TG-DTA and IR, etc.. The results showed the samples were nanocrystal accumulated porous particles, with average particle size of 29nm. Through doping of Fe3+ ion, the photo catalytic activities of particles under Xe lamp were investigated by photodegrading the methyl orange. It was found that, the TiO2 nanocrystal doped with 0.5% Fe3+ ion (accounted as mass fraction) had the highest catalytic activity. The Fe-doped TiO2 nanocrystalline composite particles prepared in this study has high activity, is easy for separation, recovery and reuse.

Dry Sol–Gel Polycondensation of Hydrosilanes to Organosilicas Catalyzed by Colloidal Nickel Nanoparticles

2007 ◽  
Vol 7 (11) ◽  
pp. 3964-3968 ◽  
Author(s):  
Bo-Hye Kim ◽  
Myong-Shik Cho ◽  
So-Yeun Kim ◽  
You-Jeong Kim ◽  
Hee-Gweon Woo ◽  
...  
Keyword(s):  
Nickel Nanoparticles ◽  
Sol Gel ◽  
Ambient Air ◽  
Amorphous Structure ◽  
High Yield ◽  
Catalytic Activities ◽  
Molecular Weights ◽  
Air Atmosphere ◽  
Plausible Mechanism

The dry sol–gel polycondensation at toluene in ambient air atmosphere of p-X-C6H4SiH3 (X = H, CH3, CH3O, F, Cl) to silica p-X-C6H4SiO1.5 in high yield, catalyzed by colloidal nickel nanoparticles in-situ generated from nickelocene(II), nickel(II) acetate, and bis(1,5-cyclooctadiene)nickel(0), is described. Similar catalytic activities were observed for the catalysts. Similarly, the dry sol–gel polyco-condensation p-X-C6H4SiH3 (X = CH3, CH3O, F, Cl):C6H4SiH3 (9:1 mole ratio) at toluene in ambient air atmosphere of was performed to yield co-silicas (p-X-C6H4SiO1.5)9(p-X-C6H4SiO1.5)1 in high yield using nickelocene. The co-gels with higher molecular weights and TGA residue yield were obtained when compared to the homogels. The highest yield, molecular weight, polydispersity index, and TGA residue yield were obtained for p-Cl-C6H4SiH3. Some degree of unreacted Si—H bonds still remained in the gel matrix because of steric bulkiness. All the insoluble gels adopt an amorphous structure with a smooth surface. A plausible mechanism for the dry sol–gel reaction was suggested.

scholarly journals Novel Polymer–Silica Composite-Based Bifunctional Catalysts for Hydrodeoxygenation of 4-(2-Furyl)-3-Buten-2-One as Model Substance for Furfural–Acetone Aldol Condensation Products

2019 ◽  
Vol 9 (12) ◽  
pp. 2438 ◽  
Author(s):  
Michael Goepel ◽  
Ruben Ramos ◽  
Roger Gläser ◽  
David Kubička
Keyword(s):  
Noble Metals ◽  
Aldol Condensation ◽  
Sol Gel ◽  
Reaction Networks ◽  
Bifunctional Catalysts ◽  
Acidic Properties ◽  
Condensation Products ◽  
Silica Composite ◽  
Model Substance ◽  
High Yields

Novel bifunctional metal-loaded polymer–silica composite (PSC) catalysts were investigated in the hydrodeoxygenation (HDO) of 4-(2-furyl)-3-buten-2-one (FAc) as a model substance for furfural–acetone aldol condensation products. PSC catalysts were synthesized via a sol–gel method with different polymer contents and subsequently doped with different noble metals. The product composition of the HDO of FAc could be tuned by using catalysts with different polymer (i.e., acidic properties) and metal content (i.e., redox properties), showing the great potential of metal-loaded PSC materials as tunable catalysts in biomass conversions with complex reaction networks. Furthermore, high yields (>90%) of the fully hydrodeoxygenated product (n-octane) could be obtained using noble metal-loaded PSC catalysts in only 8 h of reaction time.

scholarly journals ACIDIC PROPERTIES AND CATALYTIC ACTIVITIES OF VARIOUS CYCLO-TETRAPHOSPHATES

1998 ◽  
Vol 8 (0) ◽  
pp. 119-124 ◽  
Author(s):  
HIROYUKI NARIAI ◽  
HIRONORI TANIGUCHI ◽  
HIDESHI MAKI ◽  
ITARU MOTOOKA
Keyword(s):  
Acidic Properties ◽  
Catalytic Activities

scholarly journals Effect of Mo-Doped Mesoporous Al-SSP Catalysts for the Catalytic Dehydration of Ethanol to Ethylene

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Titinan Chanchuey ◽  
Chaowat Autthanit ◽  
Bunjerd Jongsomjit
Keyword(s):  
Catalytic Activity ◽  
Gas Phase ◽  
Sol Gel ◽  
Acid Sites ◽  
Weak Acid ◽  
Acid Property ◽  
Dehydration Reaction ◽  
Ethanol Dehydration ◽  
High Concentration ◽  
Catalytic Activities

The catalytic dehydration of ethanol to ethylene over the mesoporous Al-SSP and Mo-doped Al-SSP catalysts was investigated. The Al-SSP catalyst was first synthesized by the modified sol-gel method and then doped with Mo by impregnation to obtain 1% Mo/Al-SSP and 5% Mo/Al-SSP catalysts (1 and 5 wt% of Mo). The final catalysts were characterized using various techniques such as XRD, N2physisorption, SEM/EDX, TEM, and NH3-TPD. The catalytic activity for all catalysts in gas-phase ethanol dehydration reaction was determined at temperature range of 200°C to 400°C. It was found that the most crucial factor influencing the catalytic activities appears to be the acidity. The acid property of catalysts depended on the amount of Mo loading. Increased Mo loading in Al-SSP resulted in increased weak acid sites, which enhanced the catalytic activity. Besides acidity, the high concentration of Al at surface of catalyst is also essential to obtain high activity. Based on the results, the most suitable catalyst in this study is 1% Mo/Al-SSP catalyst, which can produce ethylene yield of ca. 90% at 300°C with slight amounts of diethyl ether (DEE) and acetaldehyde.

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