Electroanalytical study of the anodic wave of 5-nitroorotic acid

1990 ◽  
Vol 102 (1) ◽  
pp. 25-29
Author(s):  
J Rodriguez Flores ◽  
L Calvo Blazquez ◽  
C Marin Sanchez ◽  
A Sanchez Misiego
Keyword(s):  
Anodic Wave

Structural changes of flavylium salts. IV. Polarographic and spectrometric examination of pelargonidin chloride

1968 ◽  
Vol 21 (1) ◽  
pp. 221 ◽  
Author(s):  
KA Harper
Keyword(s):  
Ring Opening ◽  
Structural Changes ◽  
Equilibrium Mixture ◽  
Ring Cleavage ◽  
Alkaline Solutions ◽  
Similar Reaction ◽  
Anodic Wave ◽  
Wide Ph Range ◽  
Phenolic Group ◽  
Ph Range

Pelargonidin chloride has been examined polarographically and spectrometrically in aqueous methanol over a wide pH range and the molecular changes determined. In strongly acid solutions the flavylium ion is stable, but between pH3 and pH8 ring opening to the α-diketone occurs, the process involving the pseudo-base and its 3-keto tautomer. The pseudo-base is present in the equilibrium mixture from pH3 to pH12 in amount varying with the pH. The anhydrobase, detected in the equilibrium mixture at pH6, is stable above pH7, becoming ionized as the pH is raised. Unlike the anhydrobase of the simpler flavylium salts, the anhydrobase of pelargonidin chloride does not undergo ring cleavage in strong alkali under the conditions of these experiments. Ionization of the phenolic group at C5 was indicated by a, small anodic wave in the polarograms above pH9.5, due to mercuration at C6. A similar reaction, analogous to the known catalytic mercuration of ketones, was observed for phloroglucinol and resorcinol in alkaline solutions.

Behaviour of disubstituted dithiocarbamates at the mercury electrode

1975 ◽  
Vol 28 (1) ◽  
pp. 21 ◽  
Author(s):  
TH Randle ◽  
TJ Cardwell ◽  
RJ Magee
Keyword(s):  
Surface Film ◽  
Electrochemical Behaviour ◽  
Mercury Electrode ◽  
Alkyl Substituent ◽  
Electrode Reaction ◽  
Anodic Wave ◽  
Alkyl Groups ◽  
Product Film ◽  
Triton X ◽  
General Method

The electrochemical behaviour at the mercury electrode of a series of sodium dithiocarbamates in aqueous solution has been investigated. Although the overall electrode reaction mechanism is the same as that for sodium diethyldithiocarbamate in each case, the current flowing in the main anodic wave is determined by the nature of the film of the particular insoluble mercury(II) dithiocarbamate deposited on the electrode and varies with the alkyl substituent group in the dithiocarbamate. A porous, loosely bound film which periodically bursts, causing localized stirring and large irregular currents, was indicated for large bulky alkyl groups (e.g. butyl) while for small or planar alkyl groups (e.g. methyl, tetramethylene) current inhibition was observed, suggesting a compact surface film. The influence of the surfactant Triton X-100 on the product film has also been examined. Linear sweep chronoamperometry is recommended as a general method of analysis for dithiocarbamates as the electrolysis time (and therefore the film thickness) can be selected to avoid the above interferences.

Electrochemical Synthesis of Ferrate Using Iron with 3.3% Si Anode

2011 ◽  
Vol 396-398 ◽  
pp. 1773-1776
Author(s):  
Hong Li Shang ◽  
Xue Mei Sang ◽  
Zhi Feng Tian ◽  
Yun Mei Tang
Keyword(s):  
Current Efficiency ◽  
Electrochemical Synthesis ◽  
Cyclic Voltammogram ◽  
Optimum Conditions ◽  
Anodic Wave ◽  
Optimal Current ◽  
Si Anode

A ferrate solution about 236.87mM was obtained under the optimum conditions: 16MNaOH, J=100mAcm-2, 35°C, electrolysis duration (1h), The optimal current efficiency was 45.86%. The cyclic voltammogram of iron with 3.3% Si revealed a new anodic wave between -0.2V and 0.1V versus HgO/Hg corresponding to Fe(V) production.

scholarly journals Anodic Wave Polarography of Tungstate Ion

1972 ◽  
pp. 1670-1674 ◽  
Author(s):  
Atsuyoshi SAITO
Keyword(s):  
Anodic Wave ◽  
Tungstate Ion

scholarly journals Polarographic Anodic Wave of Hydrogen Peroxide in Alkaline Solutions

1976 ◽  
Vol 49 (6) ◽  
pp. 1554-1556 ◽  
Author(s):  
Kenji Kikuchi ◽  
Teisuke Murayama
Keyword(s):  
Hydrogen Peroxide ◽  
Alkaline Solutions ◽  
Anodic Wave

Polarography of n-butylthioglycolate in aqueous media, methanol, and acetonitrile

1984 ◽  
Vol 62 (9) ◽  
pp. 1817-1821
Author(s):  
K. C. Gupta ◽  
Kalpana K. Sharma
Keyword(s):  
Aqueous Media ◽  
Mercury Electrode ◽  
Wave Characteristics ◽  
Anodic Wave ◽  
Diffusion Controlled ◽  
Dropping Mercury Electrode ◽  
Drop Time ◽  
And Diffusion ◽  
Mechanism Of The Reaction

The polarographic behaviour of n-butylthioglycolate (RSH) at the DME in aqueous media, methanol, and acetonitrile has been investigated in the presence of 0.1 M KNO3 and 0.01% thymol. The effect of pH, concentration of RSH, and drop time on the wave characteristics and the mechanism of the reaction occurring at the surface of the mercury drop have been studied. Well-defined reversible and diffusion-controlled anodic waves were obtained in aqueous media (pH 4.2), 40% methanol (pH 3.22), and 40% acetonitrile (pH 2.96). Mathematical and analytical evidence was obtained to show that the anodic wave of RSH at a dropping mercury electrode in aqueous media, 40% methanol, and 40% acetonitrile is due to the formation of the mercury complex RSHg. The dissociation constant (pK) of the mercapto group in n-butylthioglycolate is 9.6 and the diffusion coefficient in the different media are 1.17 × 10−6 cm2 s−1 (in aqueous media) 1.23 × 10−6 cm2 s−1 (in 40% methanol), and 2.43 × 10−6 cm2 s−1 (in 40% acetonitrile). The linearity of id with RSH concentration provides a rapid and precise method for the determination of RSH, down to 0.4 mM in aqueous media, methanol, and acetonitrile.

Electrochemical reduction of 2,2'-dinitrodiphenylmethane and 2,2'-dinitrobenzophenone at mercury electrodes

1983 ◽  
Vol 48 (2) ◽  
pp. 364-378 ◽  
Author(s):  
Rolf Voigtländer ◽  
Jaromír Hlavatý ◽  
Jiří Volke ◽  
Viktor Bakos
Keyword(s):  
Nitro Group ◽  
Supporting Electrolyte ◽  
Standard Addition ◽  
The Other ◽  
Anodic Wave ◽  
Mercury Electrodes ◽  
Electron Reduction ◽  
The Stability ◽  
The One

The last two compounds in a 5-membered series of aromatic dinitro compounds are reduced in a completely different manner at mercury electrodes. 2,2'-Dinitrodiphenylmethane (I) - in which a conjugation of both symmetrical moieties is ruled out - is electrolytically reduced in an eight-electron step to a bishydroxylamine this being most stable between pH 4.5 and 5.0. In processing the catholyte increase in concentration of this product leads to its intermolecular disproportionation, resulting in the formation of dibenzo[b, e]-1,2-diazepine 5-oxide (IV) and 2,2'-diaminodiphenylmethane (III). 2,2'-Dinitrobenzophenone (II) reduces at more positive potentials. Its preparative electrolysis in acetonitrile (with 0.1M-N(n-C4H9)4PF6 as supporting electrolyte) the application of which was made necessary by the low solubility of II in ethanol, proceeding in an anomalous way. In the most positive cathodic wave a radical anion results, the following cathodic wave corresponds to a 6-electron reduction of the one nitro group to an amino group while the other nitro group splits off as the anion NO-2 (this later giving an anodic wave). Its formation has been proved by standard addition in polarography and by a qualitative analytical test. The product which results through this electrode process and a follow-up chemical reaction is acridone. This in turn, reduces in the third, most negative 4-electron wave to dihydroacridine. The comparison of all substances studied in this series reveals that their reducibility decreases with respect to the link X, viz. in the sequence CO > O > S and CH2 > NH. The electrolytical reduction on mercury cathodes occurs in a similar manner with analogues where X = O, S or CH2. Here, the main intermediate is the bis-hydroxylamine the stability of which predetermines the structure of final products. The other group comprises the substances with X = CO and NH. Here the main intermediate is the 2-nitro-2'-amino-diphenyl-X which is formed in a 6-electron process taking place at one of the nitro groups. The follow-up cyclization reaction leading to seven-membered heterocyclic rings located between two benzene nuclei only occurs with analogues of the type X = CH2, O and S. A partial reduction of dinitro compounds of this series has been observed with the analogue containing the NH link although that with X = CO has generally good preconditions for this mechanism.

scholarly journals Anodic Wave Polarography of Chloranilic Acid

1977 ◽  
pp. 814-819
Author(s):  
Seiki YAMAGUCHI ◽  
Chieko MIYAGI ◽  
Yutaka YAMAKAWA ◽  
Tsutomu TSUKAMOTO
Keyword(s):  
Chloranilic Acid ◽  
Anodic Wave

Polarographic Behaviour of Orotic Acid (Vitamin B13). Anodic Wave

1989 ◽  
Vol 22 (1) ◽  
pp. 177-186 ◽  
Author(s):  
L. Calvo ◽  
J. Rodriguez ◽  
F. Vinagre ◽  
A. Sanchez
Keyword(s):  
Orotic Acid ◽  
Anodic Wave ◽  
Polarographic Behaviour
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