Interdependencies Among Ethylene Oxidation and Chlorine Moderation Catalytic Cycles Over Promoted Ag/α-Al2O3 Catalysts

ACS Catalysis ◽  
2021 ◽  
pp. 14864-14876
Author(s):  
Krishna R. Iyer ◽  
Aditya Bhan
Keyword(s):  
Ethylene Oxidation ◽  
Α Al2o3 ◽  
Catalytic Cycles

Preparation and Properties of Porous α-Al2O3 Based Ceramic Disk Substrates

2013 ◽  
Vol 28 (6) ◽  
pp. 599-604 ◽  
Author(s):  
Sheng-Bo CHEN ◽  
Xu-Guang LIU ◽  
Bao-Quan ZHANG
Keyword(s):  
Ceramic Disk ◽  
Α Al2o3

Piperazine as an Inexpensive and Efficient Ligand for Pd-Catalyzed Homocoupling Reactions to Synthesize Bipyridines and Their Analogues

2019 ◽  
Vol 16 (1) ◽  
pp. 173-180
Author(s):  
Mingwei Chen ◽  
Jinyu Hu ◽  
Xiaoli Tang ◽  
Qiming Zhu
Keyword(s):  
Transition Metal ◽  
Oxidation State ◽  
Coupling Reaction ◽  
Aryl Halides ◽  
Metal Species ◽  
Good Substrate ◽  
Active Metal ◽  
Homocoupling Reaction ◽  
Catalytic Cycles ◽  
Reductive Homocoupling

Aim and Objective: The synthesis of bipyridines, especially 2, 2’-bipyridines, remains challenging because the catalytic cycle can be inhibited due to coordination of bipyridine to transition metal. Thus, the development of efficient methods for the synthesis of bipyridines is highly desirable. In the present work, we presented a promising approach for preparation of bipyridines via a Pd-catalyzed reductive homocoupling reaction with simple piperazine as a ligand. Materials and Methods: Simple and inexpensive piperazine was used as a ligand for Pd-catalyzed homocoupling reaction. The combination of Pd(OAc)2 and piperazine in dimethylformamide (DMF) was observed to form an excellent catalyst and efficiently catalyzed the homocoupling of azaarenyl halides, in which DMF was used as the solvent without excess reductants although stoichiometric reductant was generally required to generate the low-oxidation-state active metal species in the catalytic cycles. </P><P> Results: In this case, good to excellent yields of bipyridines and their (hetero) aromatic analogues were obtained in the presence of 2.5 mol% of Pd(OAc)2 and 5 mol% of piperazine, using K3PO4 as a base in DMF at 140°C. Conclusion: According to the results, piperazine as an inexpensive and efficient ligand was used in the Pd(OAc)2-catalyzed homocoupling reaction of heteroaryl and aryl halides. The coupling reaction was operationally simple and displayed good substrate compatibility.

Epitaxial mist chemical vapor deposition growth and characterization of Cu3N films on (0001)α-Al2O3 substrates

2020 ◽  
Vol 13 (7) ◽  
pp. 075505
Author(s):  
Tomohiro Yamaguchi ◽  
Hiroki Nagai ◽  
Takanori Kiguchi ◽  
Nao Wakabayashi ◽  
Takuto Igawa ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Growth ◽  
Α Al2o3

scholarly journals The Influence of Aluminum Content on Oxidation Resistance of New-Generation ODS Alloy at 1200 °C

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1478 ◽  
Author(s):  
Luděk Stratil ◽  
Vít Horník ◽  
Petr Dymáček ◽  
Pavla Roupcová ◽  
Jiří Svoboda
Keyword(s):  
Oxidation Resistance ◽  
Cross Sections ◽  
Aluminum Content ◽  
Energy Dispersive Spectrometer ◽  
Oxide Dispersion Strengthened ◽  
Xrd Analysis ◽  
Al Content ◽  
Α Al2o3 ◽  
New Generation ◽  
Ods Alloy

The aim of the paper is to evaluate the effect of aluminum content on the oxidation resistance of new-generation of oxide dispersion strengthened (ODS) alloy at 1200 °C. Three grades of the alloy of chemical composition Fe-15Cr-xAl-4Y2O3 with different Al contents x = 0.3 wt.%, 2.0 wt.% and 5.5 wt.% are prepared by mechanical alloying. The alloys are consolidated by high temperature rolling followed by heat treatment. To study the oxidation resistance the samples are isothermally aged in the air for 1 h, 4 h, 16 h and 64 h at 1200 °C. The oxidation kinetics, composition and formation mechanism of the oxide layers are analyzed. The weight gain of prepared steels is estimated. The kinetics of oxidation is studied on metallographic cross-sections of the exposed samples by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) analysis. The oxides on the surfaces are identified by X‑ray diffraction (XRD) analysis. The Al content significantly enhances the oxidation resistance of the alloy. For a sufficiently high Al content in the alloy a compact oxide layer of α‑Al2O3 on the surface is formed, which significantly suppresses further oxidation process.

On the nature of the violet luminescence in quenched α - Al2O3 single crystals

1980 ◽  
Vol 62 (1) ◽  
pp. K85-K87 ◽  
Author(s):  
A. V. Pujats ◽  
M. J. Springis ◽  
J. A. Valbis
Keyword(s):  
Single Crystals ◽  
Violet Luminescence ◽  
Α Al2o3

The morphology of α-Al2O3 and α-Fe2O3: The importance of surface relaxation

1987 ◽  
Vol 80 (2) ◽  
pp. 441-446 ◽  
Author(s):  
W.C. Mackrodt ◽  
R.J. Davey ◽  
S.N. Black ◽  
R. Docherty
Keyword(s):  
Surface Relaxation ◽  
Α Al2o3

scholarly journals Gas Permeation Properties of High-Silica CHA-Type Zeolite Membrane

Membranes ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 249
Author(s):  
Yasuhisa Hasegawa ◽  
Chie Abe ◽  
Mayumi Natsui ◽  
Ayumi Ikeda
Keyword(s):  
Molecular Size ◽  
Gas Permeation ◽  
Zeolite Membrane ◽  
Type Zeolite ◽  
High Silica ◽  
Separation Of Co2 ◽  
Α Al2o3 ◽  
Separation Performances ◽  
Molecular Sieving ◽  
Permeation Properties

The polycrystalline CHA-type zeolite layer with Si/Al = 18 was formed on the porous α-Al2O3 tube in this study, and the gas permeation properties were determined using single-component H2, CO2, N2, CH4, n-C4H10, and SF6 at 303–473 K. The membrane showed permeation behavior, wherein the permeance reduced with the molecular size, attributed to the effect of molecular sieving. The separation performances were also determined using the equimolar mixtures of N2–SF6, CO2–N2, and CO2–CH4. As a result, the N2/SF6 and CO2/CH4 selectivities were as high as 710 and 240, respectively. However, the CO2/N2 selectivity was only 25. These results propose that the high-silica CHA-type zeolite membrane is suitable for the separation of CO2 from CH4 by the effect of molecular sieving.

scholarly journals Prediction on the multiplet energy diagram of α-Al2O3: Mn4+ under pressure

2021 ◽  
Vol 1869 (1) ◽  
pp. 012107
Author(s):  
M Novita ◽  
D Marlina ◽  
H Kusumo ◽  
M T Anwar ◽  
K Ogasawara
Keyword(s):  
Energy Diagram ◽  
Α Al2o3
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