Effect of the Solvent Basicity and Additives on the Electroreduction of Picric Acid and Tetramethylammonium Picrate in Aprotic Media

1997 ◽  
Vol 62 (4) ◽  
pp. 581-596 ◽  
Author(s):  
Pavel Janderka ◽  
Oldřich Fischer ◽  
Eva Fischerová
Keyword(s):  
Cyclic Voltammetry ◽  
Reduction Potential ◽  
Electrochemical Behaviour ◽  
Picric Acid ◽  
Strong Acid ◽  
Proton Acceptor ◽  
Reduction Mechanism ◽  
Basic Alumina ◽  
Pulse Polarography ◽  
Solvent Basicity

The electroreduction of picric acid and tetramethylammonium picrate in acetonitrile, acetone, N,N-dimethylformamide, dimethyl sulfoxide and hexamethylphosphoramide has been studied by normal pulse polarography, cyclic voltammetry and by coulometric analysis. The reduction of undissociated acid starts in all aprotic media with consumption of one electron. The reduction potential is shifted to more negative potentials with rising basicity of the solvent, i.e. with rising dissociation constant of picric acid. The formation of anion radicals is followed by the sequence of acido-basic selfprotonation reactions as well as by the disproportionation leading to a nitroso intermediate. The reduction mechanism does not change by addition of proton acceptor (basic alumina) or by amfiprotic species (anthranilic acid). In the presence of a strong acid, picric acid can mediate the electroreduction of added protons. Proposed mechanisms were supported by comparison with electrochemical behaviour of related nitrophenols in the same aprotic media.

Electrochemical Behaviour of 3-Pyridyl-N,N-bis[(8-quinolyl)amino]methane

1993 ◽  
Vol 58 (6) ◽  
pp. 1279-1284
Author(s):  
Angeles Loeches ◽  
Carmen Teijeiro ◽  
Dolores Marín
Keyword(s):  
Cyclic Voltammetry ◽  
Limit Of Detection ◽  
Electrochemical Behaviour ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Reduction Mechanism ◽  
Pulse Polarography ◽  
Dc Polarography ◽  
The Waves

3-Pyridyl-N,N-bis[(8-quinolyl)amino]methane was studied by DC polarography, coulometry, cyclic voltammetry and differential pulse polarography in a system comprising Britton-Robinson buffer and 15 vol.% ethanol at pH 7.0. The nature of the waves was investigated, and the reduction mechanism is suggested. DPP was also used for a quantitative determination of the substance, and a limit of detection of 3 μmol l-1 was obtained.

Electrochemical reduction of benzenediazonium salts in aprotic medium

1989 ◽  
Vol 54 (6) ◽  
pp. 1496-1507
Author(s):  
Pavel Janderka ◽  
Igor Cejpek
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Reduction ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Reduction Mechanism ◽  
Aprotic Medium ◽  
Pulse Polarography ◽  
Dc Polarography ◽  
Donor Numbers

DC polarography, TAST polarography, differential pulse polarography, polarography with superimposed alternating current, slow cyclic voltammetry with a hanging Hg drop electrode and a Pt electrode, rapid cyclic voltammetry with a hanging Hg drop, and coulometry were used to study the electrochemical reduction of p-methoxy- and p-nitrobenzenediazonium cations in aprotic medium. A reduction mechanism involving two separate one-electron steps is proposed, the first of which being complicated by adsorption and follow-up chemical reaction leading to evolution of nitrogen. The basicity of the aprotic solvents, expressed by donor numbers according to Gutman, influences the reduction mechanism of these cations.

Polarography of N,N-dimethyl-4-amino-4'-hydroxyazobenzene in water-methanol mixtures

1985 ◽  
Vol 50 (3) ◽  
pp. 712-725 ◽  
Author(s):  
Jiří Barek ◽  
Lubomír Kelnar
Keyword(s):  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Polarographic Reduction ◽  
Reduction Mechanism ◽  
Pulse Polarography ◽  
Methanol Medium

The polarographic reduction of N,N-dimethyl-4-amino-4'-hydroxyazobenzene in water-methanol medium was investigated. Evidence is presented for adsorption of the depolarizer on the electrode, and a reduction mechanism is proposed. Conditions are indicated for the determination of this compound in the concentration range 10-4-10-6 mol/l by d.c. polarography, 10-5 to 3 . 10-7 mol/l by Tast polarography, and 10-5-3 . 10-8 mol/l by differential pulse polarography.

On the electroreduction mechanism of halobenzenes: Detection of intermediates in reduction of monohalobenzenes

1989 ◽  
Vol 54 (4) ◽  
pp. 900-910 ◽  
Author(s):  
Juan Casado ◽  
Iluminada Gallardo
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Behaviour ◽  
Experimental Results ◽  
Disk Electrode ◽  
Rotating Ring Disk Electrode ◽  
Mercury Cathode

Experimental results from electrochemical behaviour of halobenzenes in DMF at a mercury cathode are used to discuss alternative mechanisms of reduction. Intermediates of these mechanisms, such as phenyl anion, phenylmercury radical and phenylmercury cation have been detected at the electrode by using cyclic voltammetry and a rotating ring-disk electrode.

Octafluoro[2.2]paracyclophane (AF4) Quinone

2008 ◽  
Vol 73 (12) ◽  
pp. 1764-1776
Author(s):  
Wei Xu ◽  
William R. Dolbier ◽  
Jian-Xin Duan ◽  
Yian Zhai ◽  
Katsu Ogawa ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Reduction Potential ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction

Octafluoro[2.2]paracyclophane (AF4) has been oxidized by treatment with HIO3 in CF3CO2H to form the corresponding p-quinone along with a unique triketone. This quinone undergoes reduction to the respective hydroquinone as well as a Diels-Alder reaction with 1,3-cyclohexadiene. Its reduction potential was obtained by cyclic voltammetry and is discussed in the context of other quinones.

RETRACTED: The Study of Composition and Morphology of Pd-Ag Alloy Powders by Electrodeposition

2017 ◽  
Vol 732 ◽  
pp. 81-85
Author(s):  
Chin Ming Chu ◽  
Shi Wen Yang ◽  
Shen Li Tsai ◽  
Wen Bing Yang
Keyword(s):  
Stainless Steel ◽  
Cyclic Voltammetry ◽  
Reduction Potential

Pd-Ag alloy powders were prepared on the stainless steel by DC electrodeposition. Cyclic voltammetry found the reduction potential of Pd, Ag and Pd-Ag. The composition and morphology of Pd-Ag were investigated by means of SEM, EDS.

scholarly journals Electrodeposition Behavior of Polycrystalline Ni–Mo–La Composite in Alkaline Solution

Coatings ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 299 ◽  
Author(s):  
Ning Li ◽  
Weizeng Chen ◽  
Lirong Lu ◽  
Chenghui Gao
Keyword(s):  
Cyclic Voltammetry ◽  
Alkaline Solution ◽  
Reduction Potential ◽  
Structural Phase ◽  
Reduction Process ◽  
Deposition Process ◽  
Nickel Ions ◽  
Ionic Activity ◽  
Lanthanum Ions ◽  
Metal Atoms

The polycrystalline Ni–Mo–La composite coating was obtained by electrodeposition through the addition of La3+ ions into Ni, Mo ions main salt weak alkaline solution. The obtained composite contain 0.92 at.% La. According to the law of ionic activity, the redox reaction of three kinds of metal atoms was studied by polarography and cyclic voltammetry. It was found that the addition of lanthanum ions changed the composite structural, phase, and element, and the OH− ions were deduced during the electrodeposition in alkaline solution. The introduction of lanthanum and molybdenum ions negatively shifted the reduction potential of nickel ions and broadened the peaks significantly in the deposition process, retarding the reduction and deposition rate of Ni ions, which was characterized by a multi-step reduction process of Mo and La metal atoms.

Electrochemical behaviour of zinc acetate complexes: a cyclic voltammetry study

2005 ◽  
Vol 83 (6) ◽  
pp. 300-302 ◽  
Author(s):  
R. Sekar ◽  
S. Jayakrishnan ◽  
V. S. Muralidharan
Keyword(s):  
Cyclic Voltammetry ◽  
Zinc Acetate ◽  
Electrochemical Behaviour
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