Polarography

About: Polarography is a research topic. Over the lifetime, 4772 publications have been published within this topic receiving 75478 citations.

Studies of the Voltammetric Behavior and Determination of Diazo Reactive Dyes at Mercury Electrode

Abstract: The electrochemical reduction of two reactive dyes: Procion Red HE-3B 9 (RR120) and Procion Green HE-4BD (RG19) was investigated using cyclic voltammetry, differential pulse and DCt polarography, chronoamperometry and controlled potential electrolysis at mercury electrodes. The bis-azo groups of the RR120 dye are reduced together in one single step of four electrons. The bis-azo groups of the RG19 dye are reduced in two steps owing to the difference in the electron densities promoted by the different substituents in the benzene rings adjacent to the azo groups. The bis-monochlorotriazine reactive groups in both dyes are reduced only in acidic medium in their protonated form, leading to the reduction of the triazine groups. The reduction mechanism of both reactive dyes is discussed. Both dyes can be quantified in aqueous medium by differential pulse polarography in the concentration range of 1×10−7 mol L−1 to 1×10−5 mol L−1 by monitoring the reduction of the chromophore group or the reactive group.

Electrochemistry of the nitroprusside ion in nonaqueous solvents

Abstract: : The electrochemical reduction of the pentacyanonitrosylferrate(II) anion has been studied in nonaqueous aprotic media by polarography, cyclic voltammetry and coulometry. In contrast to results from aqueous solution, the initial one electron reduction proceeds with a rapid loss of cyanide to give the blue five-coordinate tetracyanonitrosylferrate(I) anion. The tetracyanonitrosylferrate(I( anion undergoes a further quasireversible reduction and an oxidation which is reversible at fast sweep rates.

Electrolysis of N-Heterocyclic Compounds

Abstract: Publisher Summary This chapter discusses the electrolysis of N-heterocyclic compounds and emphasizes on preparative electrolysis. The polarographic results are provided to supplement the discussion and to suggest further use of preparative electrolysis. The chapter focusses on electrolysis at a controlled potential. The electrolysis of an organic compound involves one or more steps in which electrons are transferred to or from the electrode and some chemical steps before and/or after the electrochemical steps. Electrode reactions may be divided into two main types depending on whether the electron transfer occurs directly between the electrode and the substrate or whether the electron is transferred to (or from) another species, which then reacts with the substrate. The apparatus for electrolysis requires electrodes, cells and circuits. The electrolytic formation of heterocyclic systems involves ring closure reactions, ring contractions, and ring expansions. The electrode reactions of heterocyclic compounds where a reduction or oxidation of the nucleus takes place are discussed. The electrolysis of substituted heterocyclic compounds, where the electrode reaction involves the substituent directly or when it plays an essential role in determining the course of the reaction and the reductions leading to ring contractions has been described.