scholarly journals ELECTROCHEMICAL OXIDATION OF DIMETHYL SULFONE IN ALKALINE MEDIUM

2018 ◽  
Vol 61 (8) ◽  
pp. 32
Author(s):  
Magomed A. Akhmedov ◽  
Shagabudin Sh. Khidirov ◽  
Madina Yu. Kaparova
Keyword(s):  
Carbon Dioxide ◽  
Electrochemical Oxidation ◽  
Alkaline Medium ◽  
Platinum Electrode ◽  
Base Material ◽  
Physicochemical Analysis ◽  
Infrared Spectrometry ◽  
Potential Range ◽  
Preparative Electrolysis ◽  
Dimethyl Sulfone

In this paper the electrochemical oxidation of dimethyl sulfone (DMSO2) on a platinum electrode in an alkaline medium has been studied by cyclic voltammetry. It is shown that during the electrochemical oxidation of dimethylsulfone in an alkaline medium on a smooth platinum electrode, a significant suppression of the oxygen evolution (O2) occurs in the potential range of E = 1.3-2.0 V. By scanning electron microscopy methods, Raman scattering and infrared spectrometry it is shown that the main substance is the dimethyl disulfone (DMDSO2) during the anodic oxidation of DMSO2 on a platinum electrode. By the preparative electrolysis of aqueous solutions of various concentrations of DMSO2 in 0.1 M NaOH solution at controlled potentials E = 1.6 and 1.8 V it is established that the current yield of the base material is not more than 84%. Based on the data of the physicochemical analysis of the final products of preparative electrolysis, a mechanism is proposed for the formation of dimethyl disulfone in an alkaline medium. It has been shown that the oxidation of dimethyl sulfone proceeds in the oxygen region by breaking C-S bonds in the DMSO2 molecule to form methyl (CH3•) and methylsulfonic (CH3S•(O)2) radicals. It is assumed that the methylsulfone radicals readily dimerize with the formation of stable DMDSO2 molecules and are desorbed in the bulk of the solution, and the methyl radicals bind to the HO radicals to form methanol molecules. The latter is well chemisorbed on the surface of platinum with the formation of adsorbed COH particles that are oxidized on a platinum electrode with the formation and evolution of carbon dioxide (CO2) from the volume of the anolyte solution. The formation of molecules of methanol was identified by the method of chromato-mass -spectrometry, and the emission of carbon dioxide by the gravimetry.

Electrochemical behavior of amidine hydrochlorides and amidines

1995 ◽  
Vol 73 (3) ◽  
pp. 362-374 ◽  
Author(s):  
Benoit Daoust ◽  
Jean Lessard
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Oxidation ◽  
Electrochemical Behavior ◽  
Platinum Electrode ◽  
Chloride Anion ◽  
Vitreous Carbon ◽  
Reduction Peak ◽  
Oxidation Peak ◽  
Preparative Electrolysis ◽  
Discharge Potential

The electrochemical behavior of N,N-dimethyl-N′-phenylformamidine hydrochloride was studied on a platinum electrode. The oxidation peak at +0.90 V vs. Ag/Ag+ 0.01 M (in CH3CN −0.1 M LiClO4) was assigned to the oxidation of the chloride anion. N,N-Dimethyl-N′-(4-chlorophenyl)formamidine and N,N-dimethyl-N′-(2-chlorophenyl)formamidine were isolated from the preparative electrolysis of this amidine hydrochloride. The electrochemical behavior of N-phenylbenzamidine hydrochloride and N-phenylcyclohex-3-enecarboxamidine hydrochloride was also studied at platinum and at vitreous carbon. Cyclic voltammetry of a number of amidines was performed. Only N-arylbenzamidines showed a reduction peak at potentials less negative than −3.0 V vs. Ag/Ag+ 0.01 M (discharge potential of the medium at vitreous carbon). Preparative electrooxidations of all amidines studied were unsuccessful because of strong and rapid passivation of the anode. Keywords: amidine, electrochemical oxidation, chloride, amidine hydrochloride.

Adsorption and Oxidation of Thiosulfate on the Platinum Electrode in a Slightly Alkaline Medium

2000 ◽  
Vol 65 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Tomáš Loučka
Keyword(s):  
Alkaline Medium ◽  
Oxidation Reaction ◽  
Open Circuit Potential ◽  
Platinum Electrode ◽  
Adsorbed Layer ◽  
Open Circuit ◽  
Adsorbed Hydrogen ◽  
Oxidation Number ◽  
Hydrogen Electrode ◽  
Layer Region

The aim of this research was to study the oxidation and reduction of the adsorbed thiosulfate on the platinum electrode in a slightly alkaline medium. The adsorption was performed at the open circuit conditions. The reduction of the adsorbed layer in the hydrogen region is slower in a slightly alkaline medium than in acid. The mechanism of reduction and oxidation of adsorbed molecules is probably the same. The nonstationary currents measured in presence of thiosulfates showed that the change in the oxidation number does not take place during the adsorption in the double layer region. In the hydrogen region, thiosulfate replaces the adsorbed hydrogen while beeing reduced. Nonstationary currents at higher concentrations of thiosulfate indicate the presence of more layers on the electrode. Upon reaching higher concentrations of thiosulfate the oxidation reaction takes place between thiosulfate in solution and adsorbed product of its reduction. The open circuit potential of the platinum electrode measured in a thiosulfate solution was 0.780 and 0.783 V against the hydrogen electrode in the same solution.

scholarly journals Electrocatalysis of Ethanol and Methanol Electrooxidation by Composite Electrodes with NiOOH/FeOOH Supported on Reduced Graphene Oxide onto Composite Electrodes

2020 ◽  
Vol 2 (1) ◽  
pp. 2
Author(s):  
João Pedro Jenson de Oliveira ◽  
Acelino Cardoso de Sá ◽  
Leonardo Lataro Paim
Keyword(s):  
Cyclic Voltammetry ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Alkaline Medium ◽  
Methanol Electrooxidation ◽  
Potential Range ◽  
Composite Electrodes ◽  
Reduced Graphene ◽  
Iron Nickel ◽  
Nickel Oxyhydroxide

This paper presents graphite/paraffin composite electrodes modified with microparticles of nickel (Ni) and Ni-Fe alloy anchored in reduced graphene oxide (rGO); these electrodes were made by electrosynthesis. Firstly, the electrodeposition of reduced graphene oxide was made by cyclic voltammetry (CV) onto the graphite/paraffin electrodes’ surface. After electrodeposition of the rGO, iron and nickel were electrodeposited by CV with successive scans. Finally, the formation of iron-nickel oxyhydroxide on the electrode surface was performed by cyclic voltammetry in alkaline medium. The composites were investigated by field emission gun scanning electron microscopy (FEG-SEM); it was observed that the Ni microparticles had spherical shapes, while the Ni-Fe alloy did not present a defined shape. The composite electrodes were used to analysis ethanol and methanol electrooxidation in an alkaline medium of 0.10 mol L−1 of NaOH in a potential range of from −0.20 to 1.0 V (vs. Ag/AgCl) at 50 mV s−1 by CV. The electrodes were able to make the electrooxidation of ethanol at a potential of around 0.57 V for the electrode constituted by the Ni-Fe alloy and around 0.61 V for the electrode modified with Ni, and for methanol in a potential around 0.57 V for the Ni-Fe alloy and around 0.66 V for the Ni electrode. The Ni-Fe alloy electrodes showed the electrocatalysis of the alcohols in relation to Ni electrodes.

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