Electrocatalytic hydrogenation of octyl aldehyde over Pd catalysts

2007 ◽  
Vol 85 (7-8) ◽  
pp. 475-478
Author(s):  
Ciprian M Cirtiu ◽  
Hugues Ménard
Keyword(s):  
Aqueous Ethanol ◽  
Supporting Electrolyte ◽  
Catalyst Support ◽  
Current Intensity ◽  
Electrocatalytic Hydrogenation ◽  
Alumina Catalyst ◽  
Pd Catalysts ◽  
Alumina Catalysts

The electrocatalytic hydrogenation (ECH) of octyl aldehyde (octanal) to octyl alcohol (octan-1-ol) was investigated using commercial Pd/alumina catalysts in aqueous ethanol. The influence of different parameters, such as catalyst support, current intensity, polarity of solvent, supporting electrolyte, and octanal concentration, on the electrocatalytic hydrogenation of octanal was studied.Key words: octanal, octan-1-ol, Pd/alumina catalyst, electrocatalytic hydrogenation.

The electrocatalytic hydrogenation of fused poly cyclic aromatic compounds at Raney nickel electrodes: the influence of catalyst activation and electrolysis conditions

1990 ◽  
Vol 68 (7) ◽  
pp. 1218-1227 ◽  
Author(s):  
Denis Robin ◽  
Michel Comtois ◽  
Anna Martel ◽  
René Lemieux ◽  
Amoy Kam Cheong ◽  
...  
Keyword(s):  
Raney Nickel ◽  
Supporting Electrolyte ◽  
Aqueous Sodium Hydroxide ◽  
Constant Current ◽  
Electrocatalytic Hydrogenation ◽  
Catalyst Activation ◽  
Nickel Electrodes ◽  
Initial Ph ◽  
Raney Ni ◽  
Tetrabutylammonium Chloride

The electrocatalytic hydrogenation (ECH) of phenanthrene, anthracene, and naphthalene has been investigated under constant current at Raney nickel electrodes in a mixed aqueous organic medium. The influence of various parameters on the efficiency of the process determined by the current efficiency (a measure of the competition between hydrogenation and hydrogen evolution, the only two electrochemical processes occurring), the extent of hydrogenation (yield of octahydro-derivatives), and the conversion rate was studied with phenanthrene. The best conditions were ethylene glycol or propylene glycol as cosolvent containing between 1.5 to 5% of water, a neutral or slightly acidic medium containing boric acid (0.1 M) as buffer (initial pH of 2.6, final pH of 6.0–6.2), sodium chloride or tetrabutylammonium chloride as supporting electrolyte, a temperature of 80° C, and a current density of 42 to 84 mA/cm2. The most active electrodes (consisting of Raney Ni particles dispersed in a nickel matrix and surrounded by a layer of porous nickel) were obtained by leaching the dispersed alloy particles at 75 °C for 7 h in 30% aqueous sodium hydroxide. The electrohydrogenation stopped at derivatives with a single aromatic ring, namely the octahydrophenanthrenes, octahydroanthracenes, and tetralin. In a non-buffered medium, tetrahydrophenanthrene could be obtained with selectivities of 80% or better. Keywords: electrocatalytic hydrogenation, Raney nickel electrodes, phenanthrene, anthracene, naphthalene.

Electrochemical removal of carbamazepine in water with Ti/PbO2 cylindrical mesh anode

2015 ◽  
Vol 73 (5) ◽  
pp. 1155-1165 ◽  
Author(s):  
J. D. García-Espinoza ◽  
P. Gortáres-Moroyoqui ◽  
M. T. Orta-Ledesma ◽  
P. Drogui ◽  
P. Mijaylova-Nacheva
Keyword(s):  
Supporting Electrolyte ◽  
Oxygen Demand ◽  
Electrochemical Reactor ◽  
Operating Conditions ◽  
Current Intensity ◽  
Oxygen Flux ◽  
Order Kinetic ◽  
Electrolysis Time ◽  
Direct Oxidation

Carbamazepine (CBZ) is one of the most frequently detected organic compounds in the aquatic environment. Due to its bio-persistence and toxicity for humans and the environment its removal has become an important issue. The performance of the electrochemical oxidation process and in situ production of reactive oxygen species (ROS), such as O3 and H2O2, for CBZ removal have been studied using Ti/PbO2 cylindrical mesh anode in the presence of Na2SO4 as supporting electrolyte in a batch electrochemical reactor. In this integrated process, direct oxidation at anode and indirect oxidation by in situ electrogenerated ROS can occur simultaneously. The effect of several factors such as electrolysis time, current intensity, initial pH and oxygen flux was investigated by means of an experimental design methodology, using a 24 factorial matrix. CBZ removal of 83.93% was obtained and the most influential parameters turned out to be electrolysis time, current intensity and oxygen flux. Later, the optimal experimental values for CBZ degradation were obtained by means of a central composite design. The best operating conditions, analyzed by Design Expert® software, are the following: 110 min of electrolysis at 3.0 A, pH = 7.05 and 2.8 L O2/min. Under these optimal conditions, the model prediction (82.44%) fits very well with the experimental response (83.90 ± 0.8%). Furthermore, chemical oxygen demand decrease was quantified. Our results illustrated significant removal efficiency for the CBZ in optimized condition with second order kinetic reaction.

On the efficiency of phenol and cyclohexanone electrocatalytic hydrogenation — Effect of conditioning and working pH in acetic acid solution on palladium/fluorine-doped tin dioxide supported catalyst

2010 ◽  
Vol 88 (5) ◽  
pp. 463-471 ◽  
Author(s):  
Dihourahouni Tountian ◽  
Anne Brisach-Wittmeyer ◽  
Paul Nkeng ◽  
Gérard Poillerat ◽  
Hugues Ménard
Keyword(s):  
Acetic Acid ◽  
Tin Dioxide ◽  
Catalyst Surface ◽  
Supporting Electrolyte ◽  
Acetic Acid Solution ◽  
Supported Catalyst ◽  
Basic Medium ◽  
Impregnation Method ◽  
Electrocatalytic Hydrogenation ◽  
Phenol Hydrogenation

The electrocatalytic hydrogenation (ECH) of phenol and cyclohexanone was performed on a conductive Pd/SnO2:F catalyst. The catalyst was obtained by the impregnation method. We studied the influence of the pH of the supporting electrolyte, the conditioning pH, and the quantity of the conditioning charge passed before hydrogenation. Fourier transform infrared spectroscopy analysis showed that the functionalization of the catalyst surface by the acetic acid electrolyte depends on the pH. A direct correlation was observed between the efficiency of the hydrogenation, the pH of the electrolyte, and the electrode conditioning charge. Phenol hydrogenation was favored in acidic media, whereas cyclohexanone hydrogenation needed an acidic medium for conditioning and a basic medium for hydrogenation. The ECH rate appeared to depend on the functionalization of the catalyst surface, the adsorption of the target organic molecule on the catalyst, and its structural modification with the pH.

Mocvd Palladium and Platinum Supported on Alumina Catalysts: Preparation and Characterization

1997 ◽  
Vol 497 ◽  
Author(s):  
Z. K. Lopez ◽  
J. R. Vargas ◽  
M. A. Valenzuela ◽  
D. R. Acosta
Keyword(s):  
Particle Size ◽  
Auger Spectroscopy ◽  
Pt Catalysts ◽  
Hrem Image ◽  
Alumina Catalyst ◽  
Pd Catalysts ◽  
Deposition Zone ◽  
Mocvd Reactor ◽  
Operation Conditions ◽  
Catalysts Preparation

ABSTRACTAn horizontal hot-wall MOCVD reactor was used to prepare palladium and platinum catalysts supported on alumina. A conventional impregnated Pt on alumina catalyst was prepared as comparison. The solids were characterized by XRD, Auger spectroscopy, HREM and H2 -TPR. The operation conditions of the MOCVD reactor were fixed preparing several Pd catalysts until to find the appropriate deposition zone. The particle size of Pt catalysts prepared by MOCVD was at about 7 nm compared with 6 ran obtained with the Pt impregnated catalyst, measured by XRD. The HREM image of the Pt MOCVD catalyst showed a narrower particle size ranging from 1 to 4 nm. After calcination three Pt compounds were detected by TPR, which were attributed to PtO, PtO2 and Pt-Al2O3 interaction in MOCVD preparation. Additionally, a clear reduction of surface oxygens of alumina was also observed.

Ordered mesoporous alumina-supported bimetallic Pd–Ni catalysts for methane dry reforming reaction

2016 ◽  
Vol 6 (17) ◽  
pp. 6542-6550 ◽  
Author(s):  
Qingxiang Ma ◽  
Jian Sun ◽  
Xinhua Gao ◽  
Jianli Zhang ◽  
Tiansheng Zhao ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Catalyst Support ◽  
Dry Reforming ◽  
Mesoporous Alumina ◽  
Alumina Catalyst ◽  
Ni Catalysts ◽  
Methane Dry Reforming ◽  
Ordered Mesoporous ◽  
Ordered Mesoporous Alumina

To compare the influence of Pd addition to Ni supported on ordered mesoporous alumina catalyst, prepared highly ordered mesoporous alumina (MA) was used as catalyst support for methane dry reforming under atmospheric pressure.

scholarly journals Degradation of an organophosphorus insecticide in aqueous medium by Electro-Fenton process

2021 ◽  
pp. 63-72
Author(s):  
Mirvet Assassi ◽  
Farid Madjene ◽  
Abdeltif Amrane
Keyword(s):  
Biological Treatment ◽  
Supporting Electrolyte ◽  
Operating Conditions ◽  
Organophosphorus Insecticide ◽  
Current Intensity ◽  
Fenton Process ◽  
Factors Affecting ◽  
Incomplete Removal ◽  
Temperature Solution ◽  
Major Factors

This work proposes the remediation of toxic and/or refractory pollutants, such as the organophosphorus insecticide (Phosmet) which cannot be completely degraded by conventional methods like biological treatment, adsorption, flocculation, electro-flocculation, reverse osmosis, ultrafiltration, coagulation. However, these techniques have some disadvantages such as incomplete removal, therefore, the Electro-Fenton process was used. The major factors affecting the removal of Phosmet, namely the current intensity, catalyst concentration (Fe3+), temperature solution, nature of the electrolytes and oxygenation duration of the solution were studied in this work. The optimal operating conditions appeared to be: current intensity 200 mA, 0.5 mmol L-1 of Fe3+, T= 20?C, pH =3 using Na2SO4 (50 mmol L-1) as supporting electrolyte and an oxygen supply throughout all the experiments (120 min). Under these optimal conditions, the removal efficiency of the phosmet was 88%.

Carboxyl-containing microporous organic nanotube networks as a platform for Pd catalysts

RSC Advances ◽  
2016 ◽  
Vol 6 (46) ◽  
pp. 39933-39939 ◽  
Author(s):  
Yang Xu ◽  
Tianqi Wang ◽  
Zidong He ◽  
Aiqing Zhong ◽  
Kun Huang
Keyword(s):  
High Activity ◽  
Catalyst Support ◽  
Pd Catalyst ◽  
Pd Catalysts ◽  
Novel Method ◽  
First Time

A novel method that enables carboxyl-containing microporous organic nanotube networks as a Pd catalyst support (Pd@MONNs) with high activity and stability for the Suzuki–Miyaura reaction is reported for the first time.

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