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Articles de revues sur le sujet « Silicon catalysis »

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Publié le 7 juillet 2024

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1

Maruyama, Benji, et Fumio S. Ohuchi. « H2O catalysis of aluminum carbide formation in the aluminum-silicon carbide system ». Journal of Materials Research 6, n^o 6 (juin 1991) : 1131–34. http://dx.doi.org/10.1557/jmr.1991.1131.

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Aluminum carbide was found to form catalytically at aluminum-silicon carbide interfaces upon exposure to water vapor. Samples, composed of approximately 2 nm thick layers of Al on SiC, were fabricated and reacted in vacuo, and analyzed using XPS. Enhanced carbide formation was detected in samples exposed to 500 Langmuirs H2O and subsequently reacted for 600 s at 873 K. The cause of the catalysis phenomenon is hypothesized to be the weakening of silicon-carbon bonds caused by very strong bonding of oxygen atoms to the silicon carbide surface. Aluminum carbide formation is of interest because of its degrading effect on the mechanical properties of aluminum/silicone carbide reinforced metal matrix composites, as well as its effect on the electrical properties of aluminum metallizations on silicon carbide layers in microelectronic components.

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2

Baráth, Eszter. « Selective Reduction of Carbonyl Compounds via (Asymmetric) Transfer Hydrogenation on Heterogeneous Catalysts ». Synthesis 52, n^o 04 (2 janvier 2020) : 504–20. http://dx.doi.org/10.1055/s-0039-1691542.

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Based on the ever-increasing demand for optically pure compounds, the development of efficient methods to produce such products is very important. Homogeneous asymmetric catalysis occupies a prominent position in the ranking of chemical transformations, with transition metals coordinated to chiral ligands being applied extensively for this purpose. However, heterogeneous catalysts have the ability to further extend the field of asymmetric transformations, because of their beneficial properties such as high stability, ease of separation and regeneration, and the possibility to apply them in continuous processes. The main challenge is to find potential synthetic routes that can provide a chemically and thermally stable heterogeneous catalyst having the necessary chiral information, whilst keeping the catalytic activity and enantioselectivity equally high (or even higher) than the corresponding homogeneous counterpart. Within this short review, the most relevant immobilization modes and preparative strategies depending on the support material used are summarized. From the reaction scope viewpoint, metal catalysts supported on the various solid materials studied in (asymmetric) transfer hydrogenation of carbonyl compounds are selected and represent the main focus of the second part of this overview.1 Introduction2 Synthesis of Chiral Heterogeneous Catalysts2.1 Immobilization of Homogeneous Asymmetric Catalysts2.1.1 Immobilization on Inorganic Supports2.1.2 Immobilization on Organic Polymers as Supports2.1.3 Immobilization on Dendrimer-Type Materials as Supports2.1.4 Self-Supported Chiral Catalysts: Coordination Polymers2.1.5 Immobilization Using Non-Conventional Media2.2 Chirally Modified Metal Surfaces for Heterogeneous Asymmetric Catalysis3 Examples of Transfer Hydrogenation on Heterogeneous Catalysts3.1 Silicon-Immobilized Catalysts3.2 Carbon-Material-Immobilized Catalysts3.3 Polymer-Immobilized Catalysts3.4 Magnetic-Nanoparticle-Immobilized Catalysts4 Conclusions

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Hoop, Kelly A., David C. Kennedy, Trevor Mishki, Gregory P. Lopinski et John Paul Pezacki. « Silicon and silicon oxide surface modification using thiamine-catalyzed benzoin condensations ». Canadian Journal of Chemistry 90, n^o 3 (mars 2012) : 262–70. http://dx.doi.org/10.1139/v11-157.

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The benzoin condensation that involves the umpolung coupling of two aldehyde groups has been applied to the formation of functionalized silicon and silicon oxide surfaces using thiamine and other N-heterocyclic carbene (NHC) catalysis in water. This bioorthogonal conjugation of an aldehyde to a modified silicon or silicon oxide surface has been monitored and characterized using X-ray photoelectron spectroscopy and IR spectroscopy. NHC catalysis was found to be efficient in water mediating full conversion of the aldehyde functionalized silicon oxide surfaces at the interface.

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4

Shteinberg, Leon. « CATALYSIS BY PHOSPHORUS AND SILICON COMPOUNDS IN THE SYNTHESIS OF OXYNAPHTOIC ACID ANILIDES ». Ukrainian Chemistry Journal 89, n^o 1 (24 février 2023) : 46–59. http://dx.doi.org/10.33609/2708-129x.89.01.2023.46-59.

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Catalysis of the acylation of aniline with 3-hydroxy-2-naphthoic, 1-hydroxy-2-naphthoic, 2-hydroxy-1-naphthoic and 1-hydroxy-4-naphthoic acids by phosphorus P(III) and silicon Si(IV) compounds leads to the formation anilides of the corresponding hydroxynaphthoic acids under mild conditions (ortho-xylene, 146.5–147 °C) in almost quantitative yield. Among P(III) phosphorus trichloride and tribromide; phosphorous, 1-hydroxyethylidene-diphosphonic, pyrophosphorous and metaphosphorous acids; trimethyl-, dimethyl- and diethylphosphites; phosph(III)azan proved to be active catalysts; among Si(IV) – trichloro-(methyl)silane, dichloro(ethyl)silane, dichloro(dimethyl)silane, tetrachlorosilane and tetraethoxysilane are active. The catalysts were used in an amount of only 2% mole. from hydroxynaphthoic acid, which is 15–35 times less than the conventional use of the same compounds as condensing agents in the synthesis of carboxylic acid arylamides. P(V) compounds, thionyl chloride, and sulfuryl chloride practically do not exhibit catalytic activity. The presence of catalytic activity only in P(III) compounds, capable of forming phosphorous acid in the reaction mass, does not contradict to the previously proposed mechanism of P = O-nucleophilic catalysis for the reaction of substituted benzoic acids with aniline catalyzed by PCl3. In general, the use of P(III) and Si(IV) compounds as catalysts in the preparation of hydroxybenzoic and hydroxynaphthoic acid anilides successfully complements the range of catalysts, based on Ti(IV) compounds, previously used in the formation of substituted benzoic and naphthoic acid anilides (containing no aromatically bonded hydroxy group), allowing to create a universal method for their synthesis.

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5

Oestreich, Martin. « Cluster Preface : Silicon in Synthesis and Catalysis ». Synlett 28, n^o 18 (27 octobre 2017) : 2394–95. http://dx.doi.org/10.1055/s-0036-1591626.

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Martin Oestreich is Professor of Organic Chemistry at the Technische Universität Berlin. His appointment was supported by the Einstein Foundation Berlin. He received his diploma degree with Paul Knochel (Marburg, 1996) and his doctoral degree with Dieter Hoppe (Münster, 1999). After a two-year postdoctoral stint with Larry E. Overman (Irvine, 1999–2001), he completed his habilitation with Reinhard Brückner (Freiburg, 2001–2005) and was appointed as Professor of Organic Chemistry at the Westfälische Wilhelms-Universität Münster (2006–2011). He also held visiting positions at Cardiff University in Wales (2005) and at The Australian National University in Canberra (2010). Martin Oestreich’s research focuses on silicon in synthesis and catalysis, the theme of the present SYNLETT Cluster. His early work centered on the use of silicon-stereogenic silicon reagents in asymmetric catalysis, and his laboratory continues to employ them as stereochemical probes in mechanistic investigations. His research group made fundamental contributions to catalytic carbon–silicon bond formation with nucleophilic and, likewise, electrophilic silicon reagents, and Martin Oestreich is probably best known for his work in silylium-ion chemistry. Recent accomplishments of his laboratory include Friedel–Crafts-type C–H silylation, transfer hydrosilylation, and kinetic resolution of alcohols by enantioselective silylation.

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Wang, Shenghua, Chenhao Wang, Wangbo Pan, Wei Sun et Deren Yang. « Two‐Dimensional Silicon for (Photo)Catalysis ». Solar RRL 5, n^o 9 (19 août 2021) : 2100596. http://dx.doi.org/10.1002/solr.202100596.

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Wang, Shenghua, Chenhao Wang, Wangbo Pan, Wei Sun et Deren Yang. « Two‐Dimensional Silicon for (Photo)Catalysis ». Solar RRL 5, n^o 2 (février 2021) : 2170021. http://dx.doi.org/10.1002/solr.202170021.

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8

Walker, Johannes C. L., Hendrik F. T. Klare et Martin Oestreich. « Cationic silicon Lewis acids in catalysis ». Nature Reviews Chemistry 4, n^o 1 (15 novembre 2019) : 54–62. http://dx.doi.org/10.1038/s41570-019-0146-7.

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9

Oestreich, Martin. « Silicon-Stereogenic Silanes in Asymmetric Catalysis ». Synlett 2007, n^o 11 (juillet 2007) : 1629–43. http://dx.doi.org/10.1055/s-2007-980385.

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10

Hrdina, Radim, Christian E. Müller, Raffael C. Wende, Katharina M. Lippert, Mario Benassi, Bernhard Spengler et Peter R. Schreiner. « Silicon−(Thio)urea Lewis Acid Catalysis ». Journal of the American Chemical Society 133, n^o 20 (25 mai 2011) : 7624–27. http://dx.doi.org/10.1021/ja110685k.

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van Veggel, A. A., D. van den Ende, J. Bogenstahl, S. Rowan, W. Cunningham, G. H. M. Gubbels et H. Nijmeijer. « Hydroxide catalysis bonding of silicon carbide ». Journal of the European Ceramic Society 28, n^o 1 (janvier 2008) : 303–10. http://dx.doi.org/10.1016/j.jeurceramsoc.2007.06.002.

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Yang, Wan Li, Zhong Qi Shi, Zhi Hao Jin et Guan Jun Qiao. « Effect of Oxide Additives on Catalysis and Microstructure of RBSN Using Low-Purity Silicon Powder as Raw Materials ». Materials Science Forum 695 (juillet 2011) : 409–12. http://dx.doi.org/10.4028/www.scientific.net/msf.695.409.

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The three kind of oxides such as 3Y-ZrO2, Fe2O3and MgO were used as catalyst in reaction bonded silicon nitride (RBSN) with low-purity silicon powder as raw materials. The oxides can strongly promoted the nitridation ratio of RBSN, and the catalysis effects of these oxides for RBSN were investigated. After 4h nitridation, the degree of nitridation increased from 43% to 96% by adding 10wt% of 3Y-ZrO2additive comparing with the sample without additive, and the catalystic effects of Fe2O3and MgO were slightly less than 3Y-ZrO2additive. XRD patterns revealed that the main phases of the reaction products were α-Si3N4, β-Si3N4and Si-N-O intermediation. SEM micrographs show that the hexagonal columnar β-Si3N4separated from acicular α-Si3N4.

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13

Hu, Yun Feng, Bo Yang, Lin Jie Hu et Li Jie Liu. « The Preparation of Modified ZSM - 35 and its Catalysis Effect Analysis on N-Butene Isomerization ». Advanced Materials Research 898 (février 2014) : 140–43. http://dx.doi.org/10.4028/www.scientific.net/amr.898.140.

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In order to study the effect that the modified ZSM - 35 as a catalyst brings to n-butene isomerization catalysis. In this paper, by considering the performance analysis brought by different silica alumina ratio, reaction temperature, concentration of nitrogen and macro porous silica gel embellish acting on butene isomerization reaction of modified ZSM - 35 molecular sieve catalyst , Al2O3 samples being "15" shows better performance; Adding appropriate amount of silicon carbide catalyst or modified silicone can further improve the selectivity of butene; Nitrogen dilution has certain help in improving butene isomerization reaction performance.

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14

Wagler, Jörg, Uwe Böhme et Gerhard Roewer. « Silicon-Enamine Complexes : Pentacoordinate Silicon Compounds ». Angewandte Chemie International Edition 41, n^o 10 (17 mai 2002) : 1732–34. http://dx.doi.org/10.1002/1521-3773(20020517)41:10<1732 ::aid-anie1732>3.0.co;2-y.

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15

Kobayashi, Shū. « Asymmetric catalysis in aqueous media ». Pure and Applied Chemistry 79, n^o 2 (1 janvier 2007) : 235–45. http://dx.doi.org/10.1351/pac200779020235.

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Lewis acid catalysis has attracted much attention in organic synthesis because of unique reactivity and selectivity attained under mild conditions. Although various kinds of Lewis acids have been developed and applied in industry, these Lewis acids must be generally used under strictly anhydrous conditions. The presence of even a small amount of water handles the reactions owing to preferential reactions of the Lewis acids with water rather than the substrates. In contrast, rare earth and other metal complexes have been found to be water-compatible. Several catalytic asymmetric reactions in aqueous media, including hydroxymethylation of silicon enolates with an aqueous solution of formaldehyde in the presence of Sc(OTf)3-chiral bipyridine ligand or Bi(OTf)3-chiral bipyridine ligand, Sc- or Bi-catalyzed asymmetric meso-epoxide ring-opening reactions with amines, and asymmetric Mannich-type reactions of silicon enolates with N-acylhydrazones in the presence of a chiral Zn catalyst have been developed. Water plays key roles in these asymmetric reactions.

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Carvalho, Alexsander T., António Pereira Nascimento Filho, Lilian Marques Silva, Maria Lucia Pereira Silva, Joana Catarina Madaleno et Luiz Pereira. « Use of Electroless Plating Copper Thin Films for Catalysis ». Materials Science Forum 514-516 (mai 2006) : 1328–32. http://dx.doi.org/10.4028/www.scientific.net/msf.514-516.1328.

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Recently, it was demonstrated that copper thin films show good adsorption characteristics for organic polar and non-polar compounds. Also, these films when used in small cavities can favor preconcentration of these organic compounds. It is also known that copper oxide can provide catalysis of organic compounds. Therefore, the aim of this work is the study of copper thin film catalysis when used in small cavities. Copper thin films, 25 nm thick, were deposited on silicon and/or rough silicon. These films do not show oxide on the surface when analyzed by Rutherford backscattering. Also, Raman analysis of these films showed only silicon bands, due to the substrate, however infrared spectroscopy shows oxide bands for films exposed to organic compound aqueous solutions. Cavities with copper films deposited inside were tested with a continuous flow of n-hexane, acetone or 2-propanol admitted in the system. The effluent was analyzed by Quartz Crystal Microbalance. It was shown that n-hexane or acetone can be trapped. The system also shows good reproducibility. Tests of catalysis were carried out using Raman spectroscopy and heating the films up to 300°C during 3 minutes after exposure to n-hexane, 2- propanol and acetophenone – pure or saturated aqueous solution. After the exposure, Raman spectra present intense bands only for 2-propanol, indicating that adsorption easily occurs. However, after heating with all solutions it was not found only silicon bands. Raman microscopy after heating also showed copper oxide cluster formation and, eventually, graphite formation. Although the heating provides oxide copper formation, this reaction does not produce a high amount of residues, which means that catalysis is possible in this condition. Thus, a simple device using copper thin films can be useful as sample pretreatment on microTAS development.

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17

West, Robert. « Chemistry of the Silicon-Silicon Double Bond ». Angewandte Chemie International Edition in English 26, n^o 12 (décembre 1987) : 1201–11. http://dx.doi.org/10.1002/anie.198712013.

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18

Yates, D. J. C., S. K. Behal et B. H. Kear. « Studies of reactions between gaseous organo-silicon compounds and metal surfaces ». Journal of Materials Research 3, n^o 4 (août 1988) : 714–22. http://dx.doi.org/10.1557/jmr.1988.0714.

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A procedure for modifying the surface composition of catalytically active metals with silicon-containing gaseous reactants has been developed. This new gas-solid reaction method is unique in that it can be used for the in situ synthesis of catalytically interesting materials, which cannot be done by conventional solid-solid reaction techniques. Using an oxygen-free silicon compound (e.g., hexamethyldisilazane, HMDS), the metals studied fall into two categories: those that involve reaction followed by diffusion, and those that exhibit surface reaction only. The first group, consisting of the metals Ni, V, Rh, Pt and Pd, formed thick (up to 0.6μ) Si diffusion layers, after reaction at 430 °C for a few hours, with either H2/HMDS or Ar/HMDS mixtures. Under the same conditions, the second group of metals, Fe and Co, showed thin (∼ 500 Å) overlayers containing silicon, but with no diffusion. The only nonmetal (graphite) studied so far showed no reaction, within the detectability limits of Auger spectroscopy. This observation shows that these reactions are catalytically induced by certain metal surfaces; in other words, they selectively take place on metals. These findings clearly have important implications for catalysis. For example, the metal surfaces of oxide-supported metal catalysts can, in principle, be selectively modified by gas-phase reactants. This treatment can readily be accomplished in situ in the catalytic reactor. The above reactions may well result in a new class of metallic catalysts, with one of the components being silicon. Furthermore, gas-phase compounds containing the elements aluminum, boron, and germanium are known to react with metals in an analogous manner, which further extends the range of possibilities for the synthesis of new catalytic materials.

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19

Bassindale, Alan R., Yuri I. Baukov, Peter G. Taylor et Vadim V. Negrebetsky. « Proton catalysis of nucleophilic substitution at pentacoordinate silicon ». Journal of Organometallic Chemistry 655, n^o 1-2 (août 2002) : 1–6. http://dx.doi.org/10.1016/s0022-328x(02)01395-5.

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20

Cadete Santos Aires, F. J., et J. C. Bertolini. « On the Use of Silicon Nitride in Catalysis ». Topics in Catalysis 52, n^o 11 (8 mai 2009) : 1492–505. http://dx.doi.org/10.1007/s11244-009-9296-z.

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21

Kumar, Amit, Yiqun Geng et Richard R. Schmidt. « Silicon Fluorides for Acid-Base Catalysis in Glycosidations ». Advanced Synthesis & ; Catalysis 354, n^o 8 (15 mai 2012) : 1489–99. http://dx.doi.org/10.1002/adsc.201100933.

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Hrdina, Radim, Christian E. Mueller, Raffael C. Wende, Katharina M. Lippert, Mario Benassi, Bernhard Spengler et Peter R. Schreiner. « ChemInform Abstract : Silicon-(Thio)urea Lewis Acid Catalysis. » ChemInform 42, n^o 40 (8 septembre 2011) : no. http://dx.doi.org/10.1002/chin.201140073.

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Teng, Yingyue, Dingze Liu, Qiang Li, Xue Bai et Yinmin Song. « Research Progress on Application in Energy Conversion of Silicon Carbide-Based Catalyst Carriers ». Catalysts 13, n^o 2 (19 janvier 2023) : 236. http://dx.doi.org/10.3390/catal13020236.

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In modern industrial production, heterogeneous catalysts play an important role. A catalyst carrier, as a constituent of heterogeneous catalysts, is employed for supporting and loading active components. The catalyst carrier has a considerable impact on the overall acting performance of the catalysts in actual production. Therefore, a catalyst carrier should have some necessary properties such as a high specific surface area, excellent mechanical strength and wear resistance, and better thermal stability. Among the candidate materials, silicon carbide (SiC) has excellent physical and chemical properties due to its special crystal structure; these properties include outstanding thermal conductivity and remarkable mechanical strength and chemical stability. Therefore, SiC materials with a high specific surface area basically meet the requirements of catalyst carriers. Accordingly, SiC has broad application prospects in the field of catalysis and is an ideal material for preparing catalyst carriers. In the present study, we reviewed the preparation methods and the variation in the raw materials used for preparing SiC-based catalyst carriers with high specific surface areas, in particular the research progress on the application of SiC-based catalyst carriers in the field of energy-conversion in recent years. The in-depth analysis indicated that the construction of SiC with a special structure, large-scale synthesis of SiC by utilizing waste materials, low-temperature synthesis of SiC, and exploring the interaction between SiC supports and active phases are the key strategies for future industrial development; these will have far-reaching significance in enhancing catalytic efficiency, reutilization of resources, ecological environmental protection, energy savings, and reductions in energy consumption.

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Fang, Hui, Yin Wu, Jiahao Zhao et Jing Zhu. « Silver catalysis in the fabrication of silicon nanowire arrays ». Nanotechnology 17, n^o 15 (3 juillet 2006) : 3768–74. http://dx.doi.org/10.1088/0957-4484/17/15/026.

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Chen, Ying-Tian, Tso-Hsiu Ho, Chern-Sing Lim et Boon Han Lim. « Development of silicon purification by strong radiation catalysis method ». Chinese Physics B 19, n^o 11 (novembre 2010) : 118105. http://dx.doi.org/10.1088/1674-1056/19/11/118105.

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Abbate, Vincenzo, Alan R. Bassindale, Kurt F. Brandstadt et Peter G. Taylor. « Biomimetic catalysis at silicon centre using molecularly imprinted polymers ». Journal of Catalysis 284, n^o 1 (novembre 2011) : 68–76. http://dx.doi.org/10.1016/j.jcat.2011.08.019.

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Liao, Fan, Tao Wang et Mingwang Shao. « Silicon nanowires : applications in catalysis with distinctive surface property ». Journal of Materials Science : Materials in Electronics 26, n^o 7 (21 mars 2015) : 4722–29. http://dx.doi.org/10.1007/s10854-015-2949-8.

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Heilmann, Jens, et Wilhelm F. Maier. « Selective Catalysis on Silicon Dioxide with Substrate-Specific Cavities ». Angewandte Chemie International Edition in English 33, n^o 4 (3 mars 1994) : 471–73. http://dx.doi.org/10.1002/anie.199404711.

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Wang, Jianguang, Haoxiong Cui, Guoan Cheng, Xiaoling Wu et Ruiting Zheng. « Effect of Annealing Temperature on the Growth of Helium Bubbles in Silicon ». Journal of Physics : Conference Series 2350, n^o 1 (1 septembre 2022) : 012008. http://dx.doi.org/10.1088/1742-6596/2350/1/012008.

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Abstract Porous silicon has broad application prospects in the fields of Optics and catalysis. Manufacturing helium bubbles in silicon is one of the effective methods to prepare porous silicon. However, the research on the optimal parameters of this preparation technology and the growth mechanism of helium bubbles in silicon is not deep enough. In this paper, the experimental method of Ic + A is adopted. Firstly, 200 keV He ions (5 × 1016 ions / cm2) was implanted into monocrystalline silicon at room temperature, subsequent the effects of different annealing temperatures on the growth of helium bubbles in silicon were studied. It is found that after annealing at 400 °C and below, there are only some fine structures of interstitial particles in monocrystalline silicon samples. At the annealing temperature of 500 °C ~ 800 °C, two sizes of helium bubble structures appear in the defect layer, and the diameter of helium bubble increases with the increase of annealing temperature.

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Jin, Tong, Da He, Wei Li, Charles J. Stanton, Sebastian A. Pantovich, George F. Majetich, Henry F. Schaefer, Jay Agarwal, Dunwei Wang et Gonghu Li. « CO2 reduction with Re(i)–NHC compounds : driving selective catalysis with a silicon nanowire photoelectrode ». Chemical Communications 52, n^o 99 (2016) : 14258–61. http://dx.doi.org/10.1039/c6cc08240h.

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Dasog, Mita, Julian Kehrle, Bernhard Rieger et Jonathan G. C. Veinot. « Silicon Nanocrystals and Silicon-Polymer Hybrids : Synthesis, Surface Engineering, and Applications ». Angewandte Chemie International Edition 55, n^o 7 (26 novembre 2015) : 2322–39. http://dx.doi.org/10.1002/anie.201506065.

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32

Shintani, Ryo. « Recent Progress in Catalytic Enantioselective Desymmetrization of Prochiral Organosilanes for the Synthesis of Silicon-Stereogenic Compounds ». Synlett 29, n^o 04 (23 novembre 2017) : 388–96. http://dx.doi.org/10.1055/s-0036-1591839.

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It is highly important to develop efficient synthetic methods for various enantioenriched chiral compounds due to their high significance in our life. In this regard, asymmetric catalysis is one of the most attractive ways of synthesizing such compounds from achiral precursors. Although various methods have been developed for the enantioselective preparation of carbon-stereogenic compounds, the corresponding methods for silicon-stereogenic compounds are much less established. In particular, little progress has been made on catalytic enantioselective synthesis using prochiral organosilanes until recently. This account focuses on the recent progress in the catalytic enantioselective preparation of silicon-stereogenic organosilanes through desymmetrization of prochiral organosilanes.1 Introduction2 Desymmetrization of Diorganodihydrosilanes3 Desymmetrization of Tetraorganosilanes3.1 Desymmetrization through Cleavage of Silicon–Carbon Bonds3.2 Desymmetrization without Cleavage of Silicon–Carbon Bonds4 Conclusion

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Zhilin, A. S., O. I. Rebrin, M. A. Malykh, M. S. Pechurin et I. M. Kovenskiy. « Si-Cu contact mass for catalysis in coatings industry for oil and gas pipes ». Oil and Gas Studies, n^o 5 (17 novembre 2023) : 46–54. http://dx.doi.org/10.31660/0445-0108-2023-5-46-54.

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Two contact masses were obtained and analyzed for their catalytic properties in the production of hydrophobic coatings. These masses are based on the silicon-copper system and consist of 25%Cu-75%Si and 50%Cu-50%Si compositions. A standard method of copper(I) chloride reduction was optimized to obtain finely dispersed copper particles with high catalytic activity. It is shown that reduction is possible directly in contact with silicon, the resulting average diameter of copper particles is 5-10 microns in both contact masses (25%Cu-75%Si and 50%Cu-50%Si). A metallographic analysis revealed a loose morphology of the silicon-copper phase interfaces, which is necessary to enhance the catalytic activity of the contact masses. Local chemical analysis by scanning electron microscopy has established the ratio of the particle size of the initial polycrystals of copper chloride(I) and the resulting copper particles as a result of reduction on silicon. The process of deep reduction makes it possible to obtain particles up to 5 microns in size. These results provide useful insights into the formulation of coatings containing organosilicon compounds to reduce friction in hydrocarbon transport.

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Morito, Haruhiko, et Hisanori Yamane. « Double-Helical Silicon Microtubes ». Angewandte Chemie International Edition 49, n^o 21 (12 avril 2010) : 3638–41. http://dx.doi.org/10.1002/anie.200907271.

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Billing, David. « In situ PXRD studies of heterogeneous catalysts and pre-catalysts ». Acta Crystallographica Section A Foundations and Advances 70, a1 (5 août 2014) : C1178. http://dx.doi.org/10.1107/s2053273314088214.

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During the course of the last couple of years, my collaborators and I have studied a number of catalytic systems using a lab based PXRD facility at our disposal. Of particular interest to us has been the supported catalysts used in Fischer Tropsch catalysis as well as those used in the synthesis of multiwalled carbon nano tubes. These studies have all proven invaluable to the understanding of the often complex phase evolution that is an intricate and inherent part of the heterogeneous processes of interest to us. Selected results will be presented to illustrate the usefulness and value of these studies. For example below is the intensity profile of the diffraction patterns collected during the heat-treatment of the pre-catalyst: A – anatase, R – rutile, S – silicon, H – hematite and P – pseudobrookite

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SHARMA, A. « Surface characterization of copper-silicon catalysts*1 ». Journal of Catalysis 93, n^o 1 (mai 1985) : 68–74. http://dx.doi.org/10.1016/0021-9517(85)90151-4.

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Guo, Yonghong, Meng‐Meng Liu, Xujiang Zhu, Liru Zhu et Chuan He. « Catalytic Asymmetric Synthesis of Silicon‐Stereogenic Dihydrodibenzosilines : Silicon Central‐to‐Axial Chirality Relay ». Angewandte Chemie International Edition 60, n^o 25 (17 mai 2021) : 13887–91. http://dx.doi.org/10.1002/anie.202103748.

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Gerdes, Claudia, et Thomas Müller. « News from Silicon : An Isomer of Hexasilabenzene and A Metal-Silicon Triple Bond ». Angewandte Chemie International Edition 49, n^o 29 (2 juin 2010) : 4860–62. http://dx.doi.org/10.1002/anie.201001558.

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Curran, Matthew D., Thomas E. Gedris et A. E. Stiegman. « Catalysis of Silicon Alkoxide Transesterification by Early Transition Metal Complexes ». Chemistry of Materials 10, n^o 6 (juin 1998) : 1604–12. http://dx.doi.org/10.1021/cm970803u.

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Andersson, Helene, Christina Jönsson, Christina Moberg et Göran Stemme. « Consecutive microcontact printing — ligands for asymmetric catalysis in silicon channels ». Sensors and Actuators B : Chemical 79, n^o 1 (septembre 2001) : 78–84. http://dx.doi.org/10.1016/s0925-4005(01)00838-3.

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SAULT, A. « Adsorption and catalysis on silicon-modified W(110) surfaces*1 ». Journal of Catalysis 126, n^o 1 (novembre 1990) : 57–72. http://dx.doi.org/10.1016/0021-9517(90)90046-m.

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Yang, Y. M., Paul K. Chu, Z. W. Wu, S. H. Pu, T. F. Hung, K. F. Huo, G. X. Qian, W. J. Zhang et X. L. Wu. « Catalysis of dispersed silver particles on directional etching of silicon ». Applied Surface Science 254, n^o 10 (mars 2008) : 3061–66. http://dx.doi.org/10.1016/j.apsusc.2007.10.055.

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Kim, P. SG, Y. H. Tang, T. K. Sham et S. T. Lee. « Condensation of silicon nanowires from silicon monoxide by thermal evaporation — An X-ray absorption spectroscopy investigation ». Canadian Journal of Chemistry 85, n^o 10 (1 octobre 2007) : 695–701. http://dx.doi.org/10.1139/v07-054.

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We report a Si K-edge X-ray absorption fine structures (XAFS) study of silicon monoxide (SiO), the starting material for silicon nanowire preparation, its silicon nanowires, and the residue after the preparation of the starting material. The silicon nanowires were condensed onto three different substrates, (i) the wall of the furnace quartz tube, (ii) a porous silicon substrate, and (iii) a Si(100) silicon wafer. It was found that the Si K-edge XAFS of SiO exhibits identifiable spectral features characteristic of Si in 0 and 4 oxidation states as well as in intermediate oxidation states, while the SiO residue primarily shows features of Si(0) and Si(4). The XAFS suggest that SiO is not exactly a simple mixture of Si and SiO2. The silicon nanowires produced by the process exhibit morphology and luminescence property variations that depend on the nature of the substrate. X-ray excited optical luminescence (XEOL) at the O K-edge suggests an efficient energy transfer to the optical decay channel. The results and their implications are discussed.Key words: silicon nanowires, thermal evaporation, silicon monoxide, X-ray absorption fine structures, X-ray excited optical luminescence.

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Jikan, Suzi Salwah, Shehu Isah Danlami et Nur Azam Badarulzaman. « Synthesis of Polymethylvinylsiloxane from Several Silicon Compounds Followed by FTIR and NMR Techniques ». Materials Science Forum 840 (janvier 2016) : 369–74. http://dx.doi.org/10.4028/www.scientific.net/msf.840.369.

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Polymethylvinylsiloxane (PMVS) were prepared by pre-hydrolysis/condensation of several silicon compounds: methylvinydichlorosilane (MVDCS) and dimethyldichlorosilane (DMDCS) followed by catalysis equilibrium copolymerization by dibutyltin dilaurate (DBTDL). All manipulations in the experiments were performed under ambient condition. The PMVS were characterized by Fourier transform infrared spectroscopy (FTIR). This method has provided information about the structure of the polymer. The 13C NMR techniques give two sets of carbons at 1.77 ppm and 136.0 ppm consist of signals from carbons of both ligand groups, whereas 29Si NMR signals of the-22.49 ppm and-35.98 ppm region are due to silicon sites bearing the methyl and vinyl ligand groups; the 29Si signals of the - 109 ppm region are due to silicon sites without ligand groups attached.Keywords: Polymethylvinylsiloxane, copolymerization, NMR

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Krotz, Achim H., Patrick Wheeler et Vasulinga T. Ravikumar. « Phosphorothioates:β-Fragmentation versusβ-Silicon Effect ». Angewandte Chemie International Edition in English 34, n^o 21 (17 novembre 1995) : 2406–9. http://dx.doi.org/10.1002/anie.199524061.

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Boberski, Cornelia, Rainer Hamminger, Marcell Peuckert, Fritz Aldinger, Reinhard Dillinger, J�rgen Heinrich et J�rgen Huber. « High-Performance Silicon Nitride Materials ». Angewandte Chemie International Edition in English 28, n^o 11 (novembre 1989) : 1560–69. http://dx.doi.org/10.1002/anie.198915601.

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Stewart, Michael P., et Jillian M. Buriak. « Photopatterned Hydrosilylation on Porous Silicon ». Angewandte Chemie International Edition 37, n^o 23 (17 décembre 1998) : 3257–60. http://dx.doi.org/10.1002/(sici)1521-3773(19981217)37:23<3257 ::aid-anie3257>3.0.co;2-1.

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Filippou, Alexander C., Bernhard Baars, Oleg Chernov, Yury N. Lebedev et Gregor Schnakenburg. « Silicon-Oxygen Double Bonds : A Stable Silanone with a Trigonal-Planar Coordinated Silicon Center ». Angewandte Chemie International Edition 53, n^o 2 (29 novembre 2013) : 565–70. http://dx.doi.org/10.1002/anie.201308433.

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Hashmi, A. Stephen K., Tanuja Dondeti Ramamurthi, Matthew H. Todd, Althea S. K. Tsang et Katharina Graf. « Gold-Catalysis : Reactions of Organogold Compounds with Electrophiles ». Australian Journal of Chemistry 63, n^o 12 (2010) : 1619. http://dx.doi.org/10.1071/ch10342.

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Different arylgold(i), one alkynylgold(i), and one vinylgold(i) triphenylphosphane complexes were subjected to electrophilic halogenation reagents. With N-chlorosuccinimid, N-bromosuccinimid, and N-iodosuccinimid as well as the Barluenga reagent, selectively halogenated compounds were obtained. Trifluoroacetic acid, as a source of protons, leads to a clean protodeauration. With N-fluorobenzenesulfonimide or Selectfluor, exclusively a homocoupling was observed. For the precursor of the vinylgold(i) complex, a similar oxidative coupling could be induced by gold(iii) chloride. Reactions with silicon or tin electrophiles failed.

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Radlik, Monika, Wojciech Juszczyk, Erhard Kemnitz et Zbigniew Karpiński. « Pd/Alumina Catalysts for Beneficial Transformation of Harmful Freon R-22 ». Catalysts 11, n^o 10 (28 septembre 2021) : 1178. http://dx.doi.org/10.3390/catal11101178.

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Chlorodifluoromethane (R-22), the most abundant freon in the atmosphere, was subjected to successful hydrodechlorination in the presence of palladium supported on γ-alumina, at a relatively low reaction temperature (180 °C). The combination of catalytic actions of alumina (performing freon dismutation) and Pd nanoparticles (catalyzing C–Cl bond splitting in the presence of hydrogen) results in the transformation of freon into valuable, chlorine-free products: methane and fluoroform, the mixture of which is used in plasma etching of silicon and silicon nitride. Very highly metal dispersed Pt/Al2O3 catalysts, with metal particles of ~1.3 nm in size, are not as effective as Pd/Al2O3, resulting in only partial dechlorination. A long-term dechlorination screening (3–4 days) showed good catalytic stability of Pd/alumina catalysts.

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