Electrochemical behaviour of 1-{[(3-halophenyl)imino]methyl}-2-naphthol Schiff bases on graphite electrodes

2004 ◽  
Vol 82 (7) ◽  
pp. 1150-1156 ◽  
Author(s):  
Kamran Polat ◽  
Mustafa Uçar ◽  
M Levent Aksu ◽  
Hüseyin Ünver
Keyword(s):  
Cyclic Voltammetry ◽  
Schiff Bases ◽  
Volume Fraction ◽  
Preparative Electrolysis ◽  
Graphite Electrodes ◽  
Ec Mechanism ◽  
Fraction Mixture ◽  
Steady State Current ◽  
Bulk Electrolysis ◽  
Constant Potential

An electrochemical study of the reduction of 1-{[(3-halophenyl)imino]methyl}-2-naphthol compounds on graphite electrodes was carried out. All the compounds were dissolved in a 1:4 (volume fraction) mixture of tetrahydrofuran (THF) and methanol. NaClO4 (0.1 mol L–1) was used as the supporting electrolyte. Cyclic voltammetry, chronoamperometry, constant-potential coulometry (bulk electrolysis), and constant-potential preparative electrolysis were employed. The cyclic voltammetric data revealed that the reduction on graphite was irreversible and followed an EC mechanism. The diffusion coefficients and the number of electrons transferred were determined using the chronoamperometric Cottrell slope and the ultramicro electrode steady-state current. The number of electrons was also determined by bulk electrolysis. The products of the electroreduction were synthesized in milligram quantities by the use of constant-potential preparative electrolysis. These products were purified and characterized by spectroscopic methods. Based on these findings, a mechanism for the electroreduction process is proposed.Key words: electrochemical reduction, hydroxynaphthylideneaniline Schiff bases, cyclic voltammetry, ultramicro electrode.

Electrolytic reduction of o-nitrobenzyl thiocyanate in buffered solutions on mercury

1985 ◽  
Vol 50 (1) ◽  
pp. 33-41 ◽  
Author(s):  
Jaromír Hlavatý
Keyword(s):  
Acidic Medium ◽  
Reaction Path ◽  
Electrolytic Reduction ◽  
Buffer System ◽  
Height Ratio ◽  
Preparative Electrolysis ◽  
Clear Explanation ◽  
Ec Mechanism ◽  
Controlled Potential

The o-nitrobenzyl thiocyanate (I) behaves differently on the DME and on a large mercury pool electrode. Polarography did not give a sufficiently clear explanation of the reaction mechanism, only the preparative experiments yielded useful results. Whereas polarographic curves in solutions of Britton-Robinson buffer system with 50% by vol. ethanol exhibit two cathodic waves within the pH region 1-12, corresponding according to their height ratio to an uptake of 4 e and 2 e respectively, the controlled potential preparation electrolysis (CPE) and coulometry results indicate a more complicated reaction path. In the CPE carried out at the concentration of I 1 . 10 -2 mol/l the electroreductive splitting of CH2-SCN occurs as the first step. Nitrobenzyl radicals so formed react in the follow-up dimerization resulting in dibenzyl or toluene structures. Simultaneously or at a later stage the completion of the electrolytic reduction of the nitro group proceeds to the hydroxylamino group. In solution of 9 > pH > 1 the CPE of nitro compound I takes place by an ECEC mechanism yielding dibenzodiazocine III, its N-oxide IV and 2,2'-dimethylazoxybenzene (V). In course of preparative electrolysis in strongly acidic medium 2-amino-benzo(l,3)-thiazine-l-oxide (II) is formed by an EC mechanism.

Some notes on a volume fraction mixture theory and a comparison with the kinetic theory of gases

1991 ◽  
Vol 29 (5) ◽  
pp. 561-573 ◽  
Author(s):  
A.C. Hansen ◽  
R.L. Crane ◽  
M.H. Damson ◽  
R.P. Donovan ◽  
D.T. Horning ◽  
...  
Keyword(s):  
Kinetic Theory ◽  
Volume Fraction ◽  
Mixture Theory ◽  
Kinetic Theory Of Gases ◽  
Fraction Mixture

Studies on electrooxidation of lignin and lignin model compounds. Part 1: Direct electrooxidation of non-phenolic lignin model compounds

Holzforschung ◽  
2012 ◽  
Vol 66 (3) ◽  
Author(s):  
Takumi Shiraishi ◽  
Toshiyuki Takano ◽  
Hiroshi Kamitakahara ◽  
Fumiaki Nakatsubo
Keyword(s):  
Electron Transfer ◽  
Cyclic Voltammetry ◽  
Carbonyl Compounds ◽  
Model Compounds ◽  
Lignin Model Compounds ◽  
Bulk Electrolysis ◽  
Lignin Model ◽  
Dimeric Compound ◽  
High Yields ◽  
Short Time

Abstract The direct anodic oxidation of non-phenolic lignin model compounds was investigated to understand their basic behaviors. The results of cyclic voltammetry (CV) studies of monomeric model, such as 1-(4-ethoxy-3-methoxyphenyl)ethanol, are interpreted as the oxidation for Cα-carbonylation did not proceed in the reaction without a catalyst, but a base promotes this reaction. Indeed, the bulk electrolyses of the monomeric lignin model compounds with 2,6-lutidine afforded the corresponding Cα-carbonyl compounds in high yields (60–80%). It is suggested that deprotonation at Cα-H in the ECEC mechanism (E=electron transfer and C=chemical step) is important for Cα-carbonylation. In the uncatalyzed bulk electrolysis of a β-O-4 model dimeric compound, 4-ethoxy-3-methoxyphenylglycerol-β-guaiacyl ether, the corresponding Cα-carbonyl compound was not detected but as a result of Cα-Cβcleavage 4-O-ethylvanillin was found in 40% yield. In the electrolysis reaction in the presence of 2,6-lutidine (as a sterically hindered light base), the reaction stopped for a short time unexpectedly. These results indicate the different electrochemical behavior of simple monomeric model compounds and dimeric β-O-4 models. The conclusion is that direct electrooxidation is unsuitable for Cα-carbonylation of lignin.

Preparation of Polypyrrole Films Doped with Phosphomolybdic Acid in ScCO2/Water Emulsion

2011 ◽  
Vol 233-235 ◽  
pp. 1085-1088 ◽  
Author(s):  
Hao Yan ◽  
Zhang Lin Li ◽  
Fei Fei Xu
Keyword(s):  
Cyclic Voltammetry ◽  
Phosphomolybdic Acid ◽  
Water Emulsion ◽  
Reduction Behavior ◽  
Polypyrrole Films ◽  
Oxidation Reduction ◽  
Bulk Electrolysis ◽  
Voltammetry Methods ◽  
Conventional Systems ◽  
Better Than

In this paper, polypyrrole films doped with phosphomolybdic acid was prepared by bulk electrolysis with coulometry in the ScCO2/Water emulsion system. The films were characterized by Raman and cyclic voltammetry methods. The polypyrrole structure was detected by Raman spectrum. And a stable oxidation-reduction behavior with three groups of peaks attributed to the phosphomolybdic acid doped in polypyrrole was established in the cyclic voltammetry curves. Moreover, the peak current was much better than that of the films prepared in conventional systems under constant pressure without the existence of ScCO2.

scholarly journals Electrooxidation of simulated wastewater containing pharmaceutical amoxicillin on thermally prepared IrO2/Ti

2021 ◽  
Vol 11 (2) ◽  
pp. 172
Author(s):  
Thiery Auguste Foffié Appia ◽  
Lassiné Ouattara
Keyword(s):  
Cyclic Voltammetry ◽  
Reduction Rate ◽  
Oxygen Demand ◽  
Inorganic Ions ◽  
Iridium Oxide ◽  
Chloride Ions ◽  
Preparative Electrolysis ◽  
Experimental Conditions ◽  
Cod Reduction ◽  
Initial Ph

<p>The electrooxidation of amoxicillin (AMX) on the iridium oxide electrode thermally prepared (400°C) has been investigated by cyclic voltammetry and preparative electrolysis. Physical characterization by Scanning Electron Microscopy (SEM) showed that the IrO<sub>2</sub> electrode has a rough surface with pores' presence. In cyclic voltammetry, the oxidation of AMX occurs directly at the anode's surface or via the higher degree oxide of iridium oxide (IrO<sub>3</sub>).  It is noted that the oxidation process of AMX can be controlled by diffusion combined with the phenomenon of adsorption. In preparative electrolysis, the effect of several parameters has been investigated. These are the current density, the support medium, the initial pH. The findings obtained show a weak degradation of amoxicillin. The Chemical Oxygen Demand (COD) reduction rate is less than 11% under our experimental conditions, indicating that the IrO2 electrode leads to the parent compound's conversion. Also, the degradation of the organic compound is favored in a very acidic medium.<strong></strong></p><p>Furthermore, the effect of inorganic ions such as SO<sub>4</sub><sup>2-</sup>, PO<sub>4</sub><sup>3-</sup>, NO<sub>3</sub><sup>-</sup>, Cl<sup>-</sup> was evaluated. Investigations show that these ions' effects are diverse, with COD reduction rates ranging from 2.47%; 2.68%; 7.7%; 16.41%, and 71.65%, respectively, in the absence and the presence of SO<sub>4</sub><sup>2-</sup>, PO<sub>4</sub><sup>3-</sup>, NO<sub>3</sub><sup>-</sup>, Cl<sup>- </sup>ions. SO<sub>4</sub><sup>2-</sup> have virtually no effect on enhancing the degradation of amoxicillin. PO<sub>4</sub><sup>3-</sup> ions provide a slight improvement in amoxicillin degradation. As for nitrate ions, their influence is 2.31 times that of phosphate ions. Chloride ions improve the performance of the electrooxidation of amoxicillin on IrO2 very significantly. The presence of chloride ions makes it possible to go from 2928.35 (absence of inorganic ions) to 33.19 kWh per Kg of COD. This represents an energy gain of over 98%.</p>

scholarly journals Electrochemical reduction of artemisinin: Chromatographic identification of bulk electrolysis products

2019 ◽  
Vol 9 (3) ◽  
pp. 165-174 ◽  
Author(s):  
Faraja Ombwayo ◽  
Zahilis Mazzhichette ◽  
Amos Mugweru
Keyword(s):  
Cyclic Voltammetry ◽  
Sesquiterpene Lactone ◽  
Electrode Surface ◽  
Reference Electrode ◽  
Carbon Electrode ◽  
Naturally Occurring ◽  
Bulk Electrolysis ◽  
Electrolysis Products ◽  
Peroxide Bond ◽  
Prominent Peak

Artemisinin is a naturally occurring sesquiterpene lactone with an endo-peroxide bond. This drug is used for treatment of many diseases including malaria. The reduction of this molecule on an electrode surface was carried out by cyclic voltammetry as well as amperometry. Cyclic voltammetry of artemisinin generated one prominent peak wave at -1.0 V and another, smaller one at -0.3 V vs Ag/AgCl reference electrode. The bulk electrolysis of artemisinin on a carbon electrode generated two other irreversible peak waves at around -0.7 and -0.1 V. The concentration of the products was dependent on the time of electrolysis. LC-MS was used to determine the bulk electrolysis products of artemisinin. Initially dihydroartemisinin was generated as the main reduction product. Other reduction products were formed after further reduction of dyhidroartemisinin.

Spectroelectrochemical Investigation of Pentacarbonyl(pyrazine)metal(0) (Metal = Cr, Mo, W) Complexes of Group 6 Elements

2002 ◽  
Vol 57 (1) ◽  
pp. 92-98 ◽  
Author(s):  
Şeniz Özalp Yaman ◽  
Emren Esentürk ◽  
Ceyhan Kayran ◽  
Ahmet M. Önal
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Behaviour ◽  
Reference Electrode ◽  
Constant Current ◽  
Oxidation Peak ◽  
Group 6 ◽  
Constant Potential ◽  
Electrochemical Mechanism ◽  
Temperature Constant

The electrochemical behaviour of pentacarbonyl(pyrazine)metal(0) complexes of the group 6 elements was studied by cyclic voltammetry in dichloromethane-(n-Bu)4NBF4 solventelectrolyte couple at -20°C vs. Ag/Ag+ or SCE reference electrode. Constant potential electrolyses of the complexes were carried out at their first oxidation peak potentials and monitored in situ by UV-Vis spectrometry. Electrolysis of W(CO)5pz produces [W(CO)5pz]+ and a similar electrochemical mechanism is expected both for Cr(CO)5pz and Mo(CO)5pz complexes. In situ low temperature constant current ESR electrolysis also confirmed the production of [W(CO)5pz]+ after the electron transfer.

Study on Electrochemical Stripping Method of Graphene Electrode and Its Capacitive Properties

2021 ◽  
Vol 13 (4) ◽  
pp. 608-614
Author(s):  
Qi Qin ◽  
Yi-Ran Cui ◽  
Meng Song ◽  
Ji-Yuan Li ◽  
Yan-Jie Wang ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Specific Surface ◽  
Electrode Material ◽  
Cyclic Voltammetry Curve ◽  
Voltage Range ◽  
Graphene Electrode ◽  
Capacitive Properties ◽  
Stripping Method ◽  
Constant Potential ◽  
Electrochemical Stripping

Graphene has excellent properties, such as excellent conductivity, more pores, stable chemical and structural properties, high specific surface area, so it is usually used in the battery fields. In order to further explore the capacitive properties of graphene, this experiment used electrochemical stripping method, the electrochemical electrode was characterized by constant potential treatment methods, cyclic voltammetry curve, and constant current charging–discharging curve. The capacitive performance of modified graphene at different potentials was compared. If a constant potential peeling treatment is performed, the interlayer spacing of graphene increases, and this time, the specific surface area is enlarged, and the electrical properties of the graphene electrode material are correspondingly improved. Cyclic voltammetry curve results show that the graphene electrode exhibits better capacitance performance after being treated with a constant potential in neutral electrolyte. When treating with 3.1 V constant potential and voltage range of -1.1 V–1.1 V, capacitance can reach 327.273 F. The chronopotentiometry curve results show that 3.1 V graphene electrode mass ratio capacitance can reach 218.182 F/g under voltage range of -0.3 V–0.3 V, meeting the energy storage requirements of the battery industry, and it is expected to become an ideal electrode material in the field of supercapacitors.

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