Mo Oxidation State of Cd, Fe, and Ag Catalysts Under Propane Mild Oxidation Reaction Conditions

2001 ◽  
Vol 200 (2) ◽  
pp. 360-369
Author(s):  
G Costentin ◽  
J.C Lavalley ◽  
F Studer
Keyword(s):  
Oxidation State ◽  
Oxidation Reaction ◽  
Mild Oxidation ◽  
Reaction Conditions ◽  
Ag Catalysts

Kinetic Model of the 1,2-Propanediol Oxidation Reaction in the Presence of 3wt%Pd/α-Al2O3 Catalyst

2021 ◽  
Vol 903 ◽  
pp. 143-148
Author(s):  
Svetlana Cornaja ◽  
Svetlana Zhizhkuna ◽  
Jevgenija Vladiko
Keyword(s):  
Activation Energy ◽  
Lactic Acid ◽  
Kinetic Model ◽  
Catalytic Oxidation ◽  
Molecular Oxygen ◽  
Oxidation Reaction ◽  
Main Product ◽  
Oxidation Process ◽  
Water Solution ◽  
Reaction Conditions

Supported 3wt%Pd/α-Al₂O₃ catalyst was tested in selective oxidation of 1,2-propanediol by molecular oxygen. It was found that the catalyst is active in an alkaline water solution. Lactic acid was obtained as the main product of the reaction. Influence of different reaction conditions on 1,2-PDO conversion and oxidation process selectivity was studied. Partial kinetic orders of the reaction with respect to 1,2-propanediol, c0(NaOH), p(O2), n(1,2-PDO)/n(Pd)) were determined and an experimental kinetic model of the catalytic oxidation reaction was obtained. Activation energy of the process was calculated and was found to be about 53 ± 5 kJ/mol.

scholarly journals CO Oxidation on Stepped Rh Surfaces: μm-Scale Versus Nanoscale

2019 ◽  
Vol 150 (3) ◽  
pp. 605-612 ◽  
Author(s):  
Y. Suchorski ◽  
I. Bespalov ◽  
J. Zeininger ◽  
M. Raab ◽  
M. Datler ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Oxidation Reaction ◽  
Active Surface ◽  
Reaction Conditions ◽  
Miller Index ◽  
Co Oxidation Reaction ◽  
Catalytically Active ◽  
Field Emission Microscopy ◽  
Photoemission Electron

Abstract The catalytic CO oxidation reaction on stepped Rh surfaces in the 10−6 mbar pressure range was studied in situ on individual μm-sized high-Miller-index domains of a polycrystalline Rh foil and on nm-sized facets of a Rh tip, employing photoemission electron microscopy (PEEM) and field-ion/field-emission microscopy (FIM/FEM), respectively. Such approach permits a direct comparison of the reaction kinetics for crystallographically different regions under identical reaction conditions. The catalytic activity of the different Rh surfaces, particularly their tolerance towards poisoning by CO, was found to be strongly dependent on the density of steps and defects, as well as on the size (µm vs. nm) of the respective catalytically active surface. Graphic Abstract

Promotion of Ternary Pt–Sn–Ag Catalysts toward Ethanol Oxidation Reaction: Revealing Electronic and Structural Effects of Additive Metals

2018 ◽  
Vol 3 (10) ◽  
pp. 2550-2557 ◽  
Author(s):  
Sheng Dai ◽  
Tzu-Hsi Huang ◽  
Xingxu Yan ◽  
Chao-Yu Yang ◽  
Tsan-Yao Chen ◽  
...  
Keyword(s):  
Oxidation Reaction ◽  
Ethanol Oxidation ◽  
Structural Effects ◽  
Ethanol Oxidation Reaction ◽  
Ag Catalysts

scholarly journals Research into the reaction process and the effect of reaction conditions on the simultaneous removal of H2S, COS and CS2 at low temperature

RSC Advances ◽  
2018 ◽  
Vol 8 (13) ◽  
pp. 6996-7004 ◽  
Author(s):  
Xin Sun ◽  
Haotian Ruan ◽  
Xin Song ◽  
Lina Sun ◽  
Kai Li ◽  
...  
Keyword(s):  
Low Temperature ◽  
Catalytic Oxidation ◽  
Oxidation Reaction ◽  
Reaction Process ◽  
Hydrolysis Reaction ◽  
Simultaneous Removal ◽  
Catalytic Hydrolysis ◽  
Reaction Conditions ◽  
Removal Processes

The removal processes of COS, CS2 and H2S could be divided into two parts: a catalytic hydrolysis reaction and a catalytic oxidation reaction.

scholarly journals Indirect Spectrophotometric Methods for the Determination of Tadalafil

2015 ◽  
Vol 1 (2) ◽  
pp. 11 ◽  
Author(s):  
Safwan Mohammad Fraihat
Keyword(s):  
Oxidation Reaction ◽  
Indigo Carmine ◽  
Pharmaceutical Preparations ◽  
Pharmaceutical Formulations ◽  
Blue Dye ◽  
Reaction Products ◽  
Reaction Conditions ◽  
Factors Affecting ◽  
Spectrophotometric Methods

Two spectrophotometric methods were developed for the determination Tadalafil in pharmaceutical preparations. The methods are based on the oxidation reaction with known excess amount of Ce(IV) and estimation of the unreacted amount using Indigo carmine dye (Method A) and in Methylene blue dye  (Method B). the factors affecting the reaction conditions were studied and the absorbance of absorbance of the oxidation reaction products were monitored at 610 and 600 nm for methods A and B respectively. Beer's law is obeyed in the concentration ranges 11 to 50 and 10 to 55 ppm, the limits of detection and quantification are reported. The proposed method was applied to the determination of the drug in pharmaceutical formulations and the results demonstrated that the method is equally accurate, precise and reproducible as the official methods. The validity of method was established by recovery studies with satisfactory results.

scholarly journals Stroboscopic operando spectroscopy of the dynamics in heterogeneous catalysis by event-averaging

2021 ◽  
Author(s):  
Jan Knudsen ◽  
Tamires Gallo ◽  
Virgínia Boix ◽  
Marie Strømsheim ◽  
Giulio D'Acunto ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Photoelectron Spectroscopy ◽  
Oxidation Reaction ◽  
Ambient Pressure ◽  
Reaction Conditions ◽  
Catalyst Structure ◽  
Time Resolved ◽  
Co Oxidation Reaction ◽  
Surface Phases ◽  
Gas Environment

Abstract Heterogeneous catalyst surfaces are highly dynamic entities that respond rapidly to changes in their local gas environment, and the dynamics of the response is a decisive factor for the catalysts’ action and activity. Few probes are able to map catalyst structure and local gas environment simultaneously under reaction conditions at the time scales of the dynamic changes. Here we use the CO oxidation reaction over a Pd(100) surface exposed to pressures of 3 and 100 mbar of a CO + O2 gas mixture to demonstrate how such studies can be performed by time-resolved ambient pressure photoelectron spectroscopy. Central elements of the method are cyclic gas pulsing and software-based event-averaging by image recognition of spectral features. For the CO oxidation reaction over Pd(100) our main finding is that that all surface phases – the CO-covered Pd surface, a surface oxide and a thick PdOx phase – catalyse the CO oxidation reaction, in dependence on the supply of gas phase reactants.

Organocatalytic Gram-Scale Synthesis and Alkylation of Heteroaryl and Electron-Rich Aryl α-Substituted γ-Lactones

Synthesis ◽  
2019 ◽  
Vol 51 (16) ◽  
pp. 3151-3159 ◽  
Author(s):  
Maxence Bos ◽  
Floris Buttard ◽  
Alexis Vallée ◽  
Emmanuel Riguet
Keyword(s):  
Molecular Oxygen ◽  
Boronic Acid ◽  
Oxidation Reaction ◽  
Mild Oxidation ◽  
Indole Ring ◽  
Aromatic Rings ◽  
Quaternary Stereocenters

The synthesis of γ-lactones α-substituted with heterocycles and electron-rich aromatic rings is described. The method, based on a sequence involving an organocatalytic addition of boronic acid to the 5-hydroxyfuran-2(5H)-one, followed by reduction and lactonization, gives access to broad range of γ-lactones on a gram scale. Among these, γ-lactones bearing a benzofuran, a benzothiophene, and an indole ring were alkylated in mild catalytic conditions to construct α-quaternary stereocenters. Interesting mild oxidation reaction, using molecular oxygen, was also highlighted during this study.

scholarly journals RuO4-mediated oxidation of N-benzylated tertiary amines. 3. Behavior of 1,4-dibenzylpiperazine and its oxygenated derivatives

2006 ◽  
Vol 4 (4) ◽  
pp. 674-694 ◽  
Author(s):  
Horia Petride ◽  
Constantin Drăghici ◽  
Cristina Florea ◽  
Aurica Petride
Keyword(s):  
Benzoic Acid ◽  
Oxidation Reaction ◽  
Oxidation Mechanism ◽  
Tertiary Amines ◽  
Reaction Conditions ◽  
Iminium Cations ◽  
Work Up ◽  
Hydrolysis Of ◽  
Mediated Oxidation

Abstract1,4-Dibenzylpiperazine (1),-2-piperazinone (7),-2,6-piperazinedione (9), and 1-benzoyl-4-benzylpiperazine (30) were oxidized by RuO4 (generated in situ) by attack at their endocyclic and exocyclic (i.e., benzylic) aminic N-α-C-H bonds to afford various oxygenated derivatives, including acyclic diformamides, benzaldehyde, and benzoic acid. The reaction outcome was complicated by (i) the hydrolysis of diformamides, occurred during the work-up, and (ii) the reaction of benzaldehyde with the hydrolysis-derived amines giving imidazolidines and/or Schiff bases. Benzoic acid resulted from benzaldehyde only. Compounds 7, 30, and 1-benzylpiperazine, but not 9, were transiently formed during the oxidation of 1. In the same reaction conditions, 1,4-dibenzyl-2,3-(or 2,5)-piperazinedione, 1,4-dibenzyl-2,3,6-piperazinetrione, 4-benzyol-1-benzyl-2-piperazinone, and 1,4-dibenzoylpiperazine were inert. The proposed oxidation mechanism involves the formation of endocyclic and exocyclic iminium cations, as well as of cyclic enamines. The latter intermediates probably result by base-induced deprotonation of the iminium cations, provided an N +−β-proton is available. In the case of 1, the cations were trapped with NaCN as the corresponding α-aminonitriles. The statistically corrected regioselectivity (endocyclic/exocyclic) of the RuO4-induced oxidation reaction of 1, 7, and 30 was 1.2–1.3.

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