Metal supported catalysts obtained by sol-gel in the hydrosilylation of phenylacetylene with R3SiH organosilanes (R3 = Ph3, Ph2Me, and PhMe2)

2000 ◽  
Vol 78 (11) ◽  
pp. 1491-1495 ◽  
Author(s):  
Rafael Jiménez ◽  
Juan Manuel López ◽  
Jorge Cervantes
Keyword(s):  
Specific Activity ◽  
Supported Catalysts ◽  
Sol Gel ◽  
Synthetic Route ◽  
Catalytic Systems ◽  
Hydrosilylation Reaction ◽  
Solid Catalysts ◽  
Sol Gel Process ◽  
Cis And Trans ◽  
Inorganic Matrices

The hydrosilylation reaction of phenylacetylene, generated on the surface of solid catalysts (such as Pt and Ru) supported on inorganic matrices such as MgO obtained by the sol-gel process, yields vinylsilanes as the main products. The products' distribution, specific activity, and turnover reactions were determined for the case of the hydrosilylation reaction of PhC = CH with R3SiH (R = Ph3, Ph2Me, and PhMe2). For Ph3SiH and Ph2MeSiH, the presence of β-trans and α isomers is observed. Addition of PhMe2SiH to phenylacetylene leads to the formation of β (cis and trans) and α isomers. These catalytic systems provide a new synthetic route to Si—C bond formation.Key words: Vinylsilanes, sol-gel catalysts, hydrosilylation and phenylacetylene.

scholarly journals Heterogeneous Hybrid Nanocomposite Based on Chitosan/Magnesia Hybrid Films: Ecofriendly and Recyclable Solid Catalysts for Organic Reactions

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3583
Author(s):  
Metwally Madkour ◽  
Khaled D. Khalil ◽  
Fakhreia A. Al-Sagheer
Keyword(s):  
Heterogeneous Catalysts ◽  
Sol Gel ◽  
Analytical Techniques ◽  
Hybrid Films ◽  
One Pot ◽  
Solid Catalysts ◽  
Force Microscopy ◽  
Chitosan Matrix ◽  
Atomic Force ◽  
Sol Gel Process

Chitosan/magnesia hybrid films (CS-Mg) have been prepared via sol-gel process and employed as heterogeneous catalysts. An in situ generation of a magnesia network in the chitosan matrix was performed through hydrolysis/condensation reactions of magnesium ethoxide. The synthesized hybrid films were characterized using various analytical techniques, such as X-ray photo-electron spectroscopy (XPS), field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The hybrid films display excellent catalytic activities in Michael and Knoevenagel reactions via one pot or solvent-free approaches under microwave irradiation conditions. Chitosan/magnesia hybrid films, catalysed pyrimidine, benzochromene, coumarin and arylidene-malononitriles derivatives formation reactions occurred with highly efficient yields of 97%, 92%, 86% and 95% respectively. Due to the fact that the films are durable and insoluble in common organic solvents, they were easily separated and can be recycled up to five times without a considerable loss of their catalytic activity.

The Study on the Decomposition of Azo Dye by La-Modified TiO2

2010 ◽  
Vol 123-125 ◽  
pp. 276-279
Author(s):  
Kuo Shan Yao ◽  
Yung Hsu Hsieh ◽  
Yu Jie Chang ◽  
Ching Hsing Lin ◽  
Chen Yu Chang ◽  
...  
Keyword(s):  
Azo Dye ◽  
Acidic Solution ◽  
Supported Catalysts ◽  
Anatase Phase ◽  
Sol Gel ◽  
Rutile Phase ◽  
Desorption Process ◽  
Sol Gel Process ◽  
Photocatalytic Activities ◽  
20 Nm

The La/TiO2 photocatalyst was prepared by lanthanum into TiO2 structure in a sol-gel process. The catalyst was characterized by field-emission scanning electron microscope (FE-SEM), X-ray diffractometer (XRD), ESCA, and Brunauer Emmett Teller (BET) analyses. Photocatalytic activities of the supported catalysts were examined through decomposition process of azo-dye Acid Yellow 17 solution under UV irradiation. The results showed that the particle size of TiO2 is about 20 nm, and the particle of La/TiO2 is about 10 nm. The crystal structure is mainly in anatase phase, the contents of the rutile phase increase with the increase of the amount of doped lanthanum. The adsorption capacity of La/TiO2 catalysts increases with lanthanum dosage in the acidic solution. The contribution of actual photodecomposition was determined by desorption process, after the photocatalytic reaction. In the acidic solution, better photodecomposition efficiency is achieved than in the neutral or alkaline solution. The experiments demonstrated that the optimum doping of La at 10 mol %, the maximum photodecomposition in dye concertration at 15 mg L-1 and photocatalytic dosage at 0.75 g L-1, achieving the highest effect.

Characterization of Highly Active Al2O3-TiO2 Supported Pt and Pd Catalysts for Hydrodechlorination of 1,2-Dichloroethane

2018 ◽  
Vol 17 (4) ◽  
Author(s):  
A. A. Granados-Fócil ◽  
S. Núñez-Correa ◽  
N. C. Martín-Guaregua ◽  
C. García-Mendoza ◽  
L. G. Woolfolk-Frías ◽  
...  
Keyword(s):  
Specific Activity ◽  
Supported Catalysts ◽  
Sol Gel ◽  
Atomic Ratio ◽  
X Ray Diffraction ◽  
Pd Catalysts ◽  
Transmission Microscopy ◽  
Highly Active ◽  
Temperature Programmed

Abstract Al2O3-TiO2 (AT) mixed oxide with atomic ratio Al/Ti = 25 and Al2O3 (A) supports were prepared by the sol-gel method and impregnated to obtain monometallic Pd and Pt (1 wt % of metal), and bimetallic PdPt (Pd/Pt = 4) catalysts. These catalysts were tested in the gas-phase hydrodechlorination of 1,2 dichloroethane. The materials were characterized by nitrogen physisorption, X-ray diffraction analysis (XRD), temperature-programmed reduction (TPR) and high-resolution transmission microscopy (HRTEM). AT support showed a BET area (422 m2/g), slightly higher than A(374 m2/g). The specific activity for the AT supported catalysts was higher than that for the A supported catalysts. The order of activity for the AT supported catalysts was as follows: Pd> PdPt> Pt and in terms of selectivity towards non-chlorinated compounds the order was PdPt> Pd> Pt. The differences in the activities and the selectivities can be explained by the presence of different species of Pd in the supported catalysts.

Study on Photocatalytic Degradation of Phenol by ZnO Thin Films

2014 ◽  
Vol 951 ◽  
pp. 100-103
Author(s):  
Han Shui Wu ◽  
Ying Lian Wang
Keyword(s):  
Thin Films ◽  
Supported Catalysts ◽  
Sol Gel ◽  
Structural Features ◽  
Zno Thin Films ◽  
Glass Substrates ◽  
Degradation Rates ◽  
Sol Gel Process ◽  
Quartz Substrates ◽  
Uv Absorption Spectrum

ZnO thin films with excellent properties have been prepared on glass substrates and quartz substrates by sol-gel process. Structural features, surface morphology and UV absorption spectrum have been studied by XRD, AFM and UV-Vis-Nir scanning spectrophotometer. The influence of different wavelengths of UV irradiation, different substrates and different annealing temperature on photocatalytic performance have been further studied. The results show that the ZnO thin films prepared on quartz substrates, annealing at 400 oC has higher degradation rates. The experiments realize the supported catalysts, easy recycling and good catalytic effect.

The crystallization of thin-film ceramics

1992 ◽  
Vol 50 (1) ◽  
pp. 338-339
Author(s):  
J.M. Schwartz ◽  
L.F. Francis ◽  
L.D. Schmidt ◽  
P.S. Schabes-Retchkiman
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Sol Gel ◽  
Processing Route ◽  
Small Areas ◽  
Ceramic Thin Films ◽  
Complex Shapes ◽  
Sol Gel Process ◽  
Ceramic Precursors ◽  
Crystalline Ceramic

Ceramic thin films and coatings are of interest for electrical, optical, magnetic and thermal barrier applications. Critical for improved properties in thin films is the development of specific microstructures during processing. To this end, the sol-gel method is advantageous as a versatile processing route. The sol-gel process involves depositing a solution containing metalorganic or colloidal ceramic precursors onto a substrate and heating the deposited layer to form a crystalline or non-crystalline ceramic coating. This route has several advantages, including the ability to create tailored microstructures and properties, to coat large or small areas, simple or complex shapes, and to more easily prepare multicomponent ceramics. Sol-gel derived coatings are amorphous in the as-deposited state and develop their crystalline structure and microstructure during heat-treatment. We are particularly interested in studying the amorphous to crystalline transformation, because many key features of the microstructure such as grain size and grain size distribution may be linked to this transformation.

Epitaxial Growth of Sr0.3Ba0.7Nb2O6 Thin Films Prepared by Sol-Gel Process

1999 ◽  
Vol 606 ◽  
Author(s):  
Keishi Nishio ◽  
Jirawat Thongrueng ◽  
Yuichi Watanabe ◽  
Toshio Tsuchiya
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Epitaxial Growth ◽  
Raw Materials ◽  
Substrate Surface ◽  
Sol Gel ◽  
Tungsten Bronze ◽  
Monomethyl Ether ◽  
Tetragonal Tungsten Bronze ◽  
Sol Gel Process

AbstructWe succeeded in the preparation of strontium-barium niobate (Sr0.3Ba0.7Nb2O6 : SBN30)that have a tetragonal tungsten bronze type structure thin films on SrTiO3 (100), STO, or La doped SrTiO3 (100), LSTO, single crystal substrates by a spin coating process. LSTO substrate can be used for electrode. A homogeneous coating solution was prepared with Sr and Ba acetates and Nb(OEt)5 as raw materials, and acetic acid and diethylene glycol monomethyl ether as solvents. The coating thin films were sintered at temperature from 700 to 1000°C for 10 min in air. It was confirmed that the thin films on STO substrate sintered above 700°C were in the epitaxial growth because the 16 diffraction spots were observed on the pole figure using (121) reflection. The <130> and <310> direction of the thin film on STO were oriented with the c-axis in parallel to the substrate surface. However, the diffraction spots of thin film on LSTO substrate sintered at 700°C were corresponds to the expected pattern for (110).

UV Curable Organic-Inorganic Hybrid Materials

2000 ◽  
Vol 628 ◽  
Author(s):  
Guang-Way Jang ◽  
Ren-Jye Wu ◽  
Yuung-Ching Sheen ◽  
Ya-Hui Lin ◽  
Chi-Jung Chang
Keyword(s):  
Hybrid Materials ◽  
Colloidal Silica ◽  
Sol Gel ◽  
Solution Ph ◽  
Uv Curable ◽  
Inorganic Hybrid ◽  
Degradation Temperature ◽  
Sol Gel Process ◽  
The Stability ◽  
Thermal Degradation Temperature

This work successfully prepared an UV curable organic-inorganic hybrid material consisting of organic modified colloidal silica. Applications of UV curable organic-inorganic hybrid materials include abrasion resistant coatings, photo-patternable thin films and waveguides. Colloidal silica containing reactive functional groups were also prepared by reacting organic silane and tetraethyl orthosilicate (TEOS) using sol-gel process. In addition, the efficiency of grafting organic moiety onto silica nanoparticles was investigated by applying TGA and FTIR techniques. Experimental results indicated a strong interdependence between surface modification efficiency and solution pH. Acrylate-SiO2 hybrid formation could result in a shifting of thermal degradation temperature of organic component from about 200°C to near 400°C. In addition, the stability of organic modified colloidal silica in UV curable formula and the physical properties of resulting coatings were discussed. Furthermore, the morphology of organic modified colloidal silica was investigated by performing TEM and SEM studies‥

Halogenation of ORMOSIL: A Promising Rout for Tailoring Optical Absorptions

2003 ◽  
Vol 771 ◽  
Author(s):  
Amir Fardad ◽  
Wei Liang ◽  
Yadong Zhang ◽  
Bryson Case ◽  
Shibin Jiang ◽  
...  
Keyword(s):  
Process Parameters ◽  
Sol Gel ◽  
Fiber Amplifiers ◽  
Grignard Reaction ◽  
Coupling Loss ◽  
Beam Splitters ◽  
Silicon Technology ◽  
Sol Gel Process ◽  
Propagation Losses ◽  
Signal Intensities

AbstractFluorinated and photo-imageable precursors are synthesized through a Barbier-Grignard reaction for 1550-nm window. The precursors are used for the sol-gel process of integrated optic components for silica-on-silicon technology. Material compositions and process parameters are optimized to achieve internal absorptions >0.1 dB/cm and propagation losses of about 0.5 dB/cm at 1550 nm. Compact 1×16 Beam splitters are designed and fabricated which exhibit >0.3 dB power uniformity, >0.1 dB PDL and 1.5 dB coupling loss. By hybrid integration of the passive splitters and in-house fiber amplifiers, amplifying splitters are demonstrated at various signal intensities.

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