Tuning the acidic properties of aluminas via sol-gel synthesis: New findings on the active site of alumina-catalyzed epoxidation with hydrogen peroxide

2006 ◽  
Vol 244 (1) ◽  
pp. 92-101 ◽  
Author(s):  
R RINALDI ◽  
F FUJIWARA ◽  
W HOLDERICH ◽  
U SCHUCHARDT
Keyword(s):  
Hydrogen Peroxide ◽  
Active Site ◽  
Sol Gel ◽  
Acidic Properties ◽  
New Findings ◽  
Sol Gel Synthesis

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.

Sol-Gel Synthesis of Protoenstatite

1994 ◽  
Vol 346 ◽  
Author(s):  
Steven A. Jones ◽  
James M. Burlitch
Keyword(s):  
Hydrogen Peroxide ◽  
Freeze Drying ◽  
Room Temperature ◽  
Sol Gel ◽  
Processing Conditions ◽  
Freeze Dried ◽  
Lower Temperature ◽  
Nmr Methods ◽  
Sol Gel Synthesis ◽  
High Temperature Polymorph

ABSTRACTProtoenstatite, a high-temperature polymorph of enstatite (MgSiO3), is generally not stable at room temperature, and is difficult to synthesize. Using a recently developed, hydrogen peroxide-assisted, sol-gel synthesis, protoenstatite was synthesized in a form that was stable at room temperature. Its crystallization was strongly dependent on processing conditions, particularly on the manner in which the xerogel was formed and fired. Xerogels prepared by evaporation, sprav-drying and freeze-drying were compared by XRD, HTXRD, BET, TG/DTA, and 29Si NMR methods. When samples were prepared by evaporation or spray-drying, the result was a mixture of polymorphs. Only the freeze-dried precursor yielded protoenstatite at a lower temperature and within a shorter time than any previously reported.

The ethylene glycol-mediated sol-gel synthesis of nano AlF3: structural and acidic properties after different post treatments

2021 ◽  
Author(s):  
Wei Mao ◽  
Yanbo Bai ◽  
Zhaohua Jia ◽  
yue qin ◽  
bo wangbo ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Surface Acidity ◽  
Sol Gel ◽  
Acidic Properties ◽  
Sol Gel Process ◽  
Sol Gel Synthesis

In this work, the structure and surface acidity of nano AlF3 prepared by the ethylene glycol-mediated sol-gel process, followed by different post treatments including post-fluorination and calcination, were systematically investigated....

scholarly journals Non-hydrolytic sol-gel synthesis of mesoporous iron-aluminum oxide and their properties in the oxidation of hydrocarbons by hydrogen peroxide

2021 ◽  
pp. 111317
Author(s):  
Gustavo Pimenta Ricci ◽  
Larissa Oliveira Garcia ◽  
Eduardo José Nassar ◽  
Shirley Nakagaki ◽  
João Felipe Stival ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Aluminum Oxide ◽  
Sol Gel ◽  
Iron Aluminum ◽  
Oxidation Of Hydrocarbons ◽  
Sol Gel Synthesis

Inorganic-organic Hybrid Materials for Real 3-D Sub-νm Lithography

2003 ◽  
Vol 780 ◽  
Author(s):  
R. Houbertz ◽  
J. Schulz ◽  
L. Fröhlich ◽  
G. Domann ◽  
M. Popall ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Sol Gel ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Hybrid Polymer ◽  
Organic Hybrid ◽  
Two Photon ◽  
Applied Technology ◽  
Scale Structures ◽  
Sol Gel Synthesis

AbstractReal 3-D sub-νm lithography was performed with two-photon polymerization (2PP) using inorganic-organic hybrid polymer (ORMOCER®) resins. The hybrid polymers were synthesized by hydrolysis/polycondensation reactions (modified sol-gel synthesis) which allows one to tailor their material properties towards the respective applications, i.e., dielectrics, optics or passivation. Due to their photosensitive organic functionalities, ORMOCER®s can be patterned by conventional photo-lithography as well as by femtosecond laser pulses at 780 nm. This results in polymerized (solid) structures where the non-polymerized parts can be removed by conventional developers.ORMOCER® structures as small as 200 nm or even below were generated by 2PP of the resins using femtosecond laser pulses. It is demonstrated that ORMOCER®s have the potential to be used in components or devices built up by nm-scale structures such as, e.g., photonic crystals. Aspects of the materials in conjunction to the applied technology are discussed.

Sol-Gel Synthesis, Structure and Optical Properties of Nickel-Manganese Ferrites

2019 ◽  
Vol 11 (3) ◽  
pp. 03021-1-03021-5
Author(s):  
V. S. Bushkova ◽  
◽  
I. P. Yaremiy ◽  
B. K. Ostafiychuk ◽  
N. I. Riznychuk ◽  
...  
Keyword(s):  
Optical Properties ◽  
Sol Gel ◽  
Sol Gel Synthesis ◽  
Nickel Manganese

Sol-Gel Synthesis of Nano-Scale, End-Member Albite Feldspar (NaAlSi3O8)

2021 ◽  
Author(s):  
L.M. Anovitz ◽  
A. Affolter ◽  
M.C. Cheshire ◽  
A.J. Rondinone ◽  
Lawrence F. Allard
Keyword(s):  
Sol Gel ◽  
Nano Scale ◽  
Sol Gel Synthesis

scholarly journals Aqueous Sol-Gel Synthesis of Different Iron Ferrites: From 3D to 2D

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1554
Author(s):  
Justinas Januskevicius ◽  
Zivile Stankeviciute ◽  
Dalis Baltrunas ◽  
Kęstutis Mažeika ◽  
Aldona Beganskiene ◽  
...  
Keyword(s):  
Magnetic Measurements ◽  
Substrate Surface ◽  
Sol Gel ◽  
Synthesis Method ◽  
Xrd Analysis ◽  
Dip Coating ◽  
Yttrium Iron ◽  
Iron Garnet ◽  
Dip Coating Technique ◽  
Sol Gel Synthesis

In this study, an aqueous sol-gel synthesis method and subsequent dip-coating technique were applied for the preparation of yttrium iron garnet (YIG), yttrium iron perovskite (YIP), and terbium iron perovskite (TIP) bulk and thin films. The monophasic highly crystalline different iron ferrite powders have been synthesized using this simple aqueous sol-gel process displaying the suitability of the method. In the next step, the same sol-gel solution was used for the fabrication of coatings on monocrystalline silicon (100) using a dip-coating procedure. This resulted, likely due to substrate surface influence, in all coatings having mixed phases of both garnet and perovskite. Thermogravimetric (TG) analysis of the precursor gels was carried out. All the samples were investigated by X-ray powder diffraction (XRD) analysis. The coatings were also investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and Mössbauer spectroscopy. Magnetic measurements were also carried out.

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