scholarly journals Controlled Potential Electrolysis. X. Polarographic Behavior and Electrolytic Reduction Process of Esters of Aliphatic α-Nitrocarboxylic Acids

1964 ◽  
Vol 12 (12) ◽  
pp. 1397-1405 ◽  
Author(s):  
Masaichiro Masui ◽  
Hiroteru Sayo ◽  
Keiichi Kishi
Keyword(s):  
Reduction Process ◽  
Electrolytic Reduction ◽  
Polarographic Behavior ◽  
Controlled Potential Electrolysis ◽  
Controlled Potential

scholarly journals Electrochemical Behaviour of N′-(p-toluenesulphonyl)-3-methyl-4-(4′-substituted arylhydrazono) pyrazolin-5-ones

2012 ◽  
Vol 9 (4) ◽  
pp. 1864-1874
Author(s):  
V. Nagaraju ◽  
R. Sreenivasulu ◽  
P. Venkata Ramana
Keyword(s):  
Electrochemical Behaviour ◽  
Reduction Process ◽  
Effect Of Solvent ◽  
Buffer Solutions ◽  
Diffusion Controlled ◽  
Controlled Potential Electrolysis ◽  
Dc Polarography ◽  
Controlled Potential ◽  
Ph Range ◽  
And Diffusion

The electrochemical behaviour of N′-(p-toluenesulphonyl)-3-methyl-4-(4′-substituted arylhydrazono) pyrazolin-5-ones has been investigated at dme and gc electrodes in buffer solutions of pH 2.0, 4.0, 6.0, 8.0 and 10.0 using dc polarography and cyclic voltammetry and coulometry. The compounds exhibit one well defined wave in the entire pH range of study. The process is irreversible and diffusion controlled. Controlled potential electrolysis indicates the involvement of four electrons in the reduction process. The effect of solvent, cations and anions, temperature and substitutents on the mechanism of reduction has been studied. Based on the results obtained the mechanism of reduction has been suggested.

scholarly journals Differential Pulse Polarographic Determination of Procymidone in Formulations and Wine

2002 ◽  
Vol 85 (3) ◽  
pp. 731-735 ◽  
Author(s):  
Neelam Y Sreedhar ◽  
Thommandru R Babu ◽  
Kethamreddy Samatha ◽  
Devarapalli Sujatha ◽  
Thenepalli Thriveni
Keyword(s):  
Reduction Process ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Experimental Conditions ◽  
Controlled Potential Electrolysis ◽  
Pulse Polarography ◽  
Half Wave ◽  
Single Well ◽  
Controlled Potential ◽  
Ph Range

Abstract The dicarboximide fungicide procymidone was studied systematically by using direct current polarography, cyclic voltammetry, differential pulse polarography (DPP), controlled potential electrolysis, and millicoulometry in the universal buffer medium with dimethylformamide as the solvent. Procymidone exhibited a single well-defined polarographic wave in the pH range 2.0–6.0, leading to the formation of the hydroxy compound. The overall reduction process was diffusion-controlled and adsorption-free. The variation of half-wave potential with pH, the concentration of the analyte, and other experimental conditions are described. The reduction mechanism proposed is an overall 4-electron process, in which the dicarboximide group is reduced. DPP was used to determine procymidone in agricultural formulations and wine at the optimum conditions found; a detection limit of 2.4 × 10−9M was estimated. The results obtained by the proposed method were also compared with those obtained by other methods.

VOLTAMMETRIC DETERMINATION OF ACETOPHOS IN WATER SAMPLES AT CNTPE

2013 ◽  
Vol 12 (03) ◽  
pp. 1350018
Author(s):  
SARVAREDDY RAJASEKHAR REDDY ◽  
T. RAVEENDRANATH BABU
Keyword(s):  
Water Samples ◽  
Supporting Electrolyte ◽  
Reduction Process ◽  
Standard Addition ◽  
Differential Pulse ◽  
Experimental Conditions ◽  
Controlled Potential Electrolysis ◽  
Universal Buffer ◽  
Controlled Potential ◽  
Ph Range

In this paper, a sensitive differential pulse voltammetric method to determine the residues of acetophos in water samples at CNTPE were reported. The significance of CNTPE is to result in low detection limits, high sensitivities, reduction of over-potentials, high mechanical strength and high conductivity and resistance to surface fouling. The universal buffer with pH range 2.0–6.0 is used as supporting electrolyte. Cyclic voltammetry employed to evaluate electrode mechanism and number of electrons involved in reduction process were found out by using Millicoulometry and the product collected by applying Controlled potential electrolysis. Experimental conditions such as accumulation potential, accumulation time and scan rate were optimized. Calculations were made by standard addition method.

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.

Polarographic Behaviour of Some Arylazotheophyllines

1993 ◽  
Vol 58 (9) ◽  
pp. 1978-1988
Author(s):  
Mohamed I. Ismail ◽  
Madlene L. Iskander
Keyword(s):  
Diffusion Coefficient ◽  
Model Compound ◽  
Aqueous Media ◽  
Chemical Characteristics ◽  
Polarographic Behaviour ◽  
Physico Chemical ◽  
Controlled Potential Electrolysis ◽  
Azo Group ◽  
Controlled Potential ◽  
Electrolysis Products

The polarographic behaviour of a series of arylazotheophyllines was studied in aqueous alcoholic buffer media and in DMF-0.1 M LiClO4 solution. The redox study gave evidence that the azo group is electroactive in aqueous as well as non-aqueous media. A mechanism interpreting the electrode process is proposed and confirmed through the identification of the controlled potential electrolysis products, the use of a model compound and the application of Hamett's σ-E relationship. The physico-chemical characteristics of these compounds, viz. the diffusion coefficient, dissociation constant, ionization potential and electron affinity, are also included.

Substituent effects on polarographic reduction of some photographic color intermediates

1976 ◽  
Vol 54 (8) ◽  
pp. 1205-1210 ◽  
Author(s):  
Ahmad S. Shawali ◽  
Bahgat E. El-Anadouli
Keyword(s):  
Dissociation Constants ◽  
Substituent Effects ◽  
Protonated Form ◽  
Acid Dissociation ◽  
Polarographic Reduction ◽  
Substituent Constant ◽  
Acid Dissociation Constants ◽  
Controlled Potential Electrolysis ◽  
Half Wave ◽  
Controlled Potential

Polarographic reduction of two series of benzoylacetanilides has been investigated in 40% (by volume) ethanolic Britton–Robinson buffers. One series (A) contains substituents on the anilide moiety, and the second (B) has substituents on both the anilide and benzoyl moieties. Polarographic controlled-potential electrolysis data indicate that the electroactive species in both series is the protonated form (ArCOCH2CONHAr′)H+. The reduction half-wave potentials of anilides of series A were found to be independent of the nature of the substituent, whereas those of series B show a good linear relationship when plotted vs. the σ substituent constant of the substituent on the benzoyl moiety (ρ = 0.284, r = 0.995). Values of the acid dissociation constants of the keto (K1) and enol (K2) tautomers of the anilides of series A were calculated; unlike their E1/2 values, the pK1 data show a linear correlation with the Hammett substituent constant, σ. The pK2 values show, however, little variation with σ.

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