Showing papers on "Supporting electrolyte published in 1979"
TL;DR: In this article, coal is consumed within an aqueous electrolyte to produce gaseous oxides of carbon at the anode and hydrogen at the cathode, and an abrupt and reproducible jump in potential is observed which suggests at least two different mechanisms for the overall process.
80 citations
TL;DR: In this article, the authors investigated the transfer of tetraalkyl (from tetraethyl to tetrapentyl) ammonium ions (R+) from water to nitrobenzene by means of chronopotentiometric measurements.
60 citations
TL;DR: In this paper, the electrochemical reduction of allyl iodide, allyl bromide and allyl anion was studied in dry acetonitrile with TBAP as supporting electrolyte by means of cyclic voltammetry.
Abstract: The electrochemical reduction of allyl iodide ( la ) , allyl bromide ( l b ) , (E)-3-bromo-l-phenyl-l-propene (IC), and (E)-5-bromo-2,2,6,6-tetramethyl-3-heptene ( Id ) was studied in dry acetonitrile with TBAP as supporting electrolyte by means of cyclic voltammetry and coulometry at mercury, platinum, and vitreous carbon electrodes. Compounds la-c showed multiple waves on platinum and mercury because of halide surface effects. However on vitreous carbon la-d gave single reduction waves, with half-peak potentials of -1.38, -1.64, -1 .1 I , and -1.89 V (vs. SCE), respectively. Apparent coulometric n values of 1 for la-c were shown to arise from rapid nucleophilic substitution of the allyl anion intermediates with starting halide to give electroinactive dimers. Sterically hindered Id showed an napp of 2 and did not exhibit surface interactions with Hg and Pt. Thus allyl halides, contrary to previous statements in the literature, are reduced via a two-electron electrode reaction and the reduction of the allyl radical to the allyl anion cannot be seen as a separate step. Evidence was also obtained for the formation of the allyl anion by reduction of l a and I b with solvated electrons in liquid ammonia; the electrochemical oxidation of this species in this medium occurred at ca. -1.2 V.
53 citations
TL;DR: In this article, the authors proposed a square-type reaction scheme to interpret the behavior of the nickel hydroxide electrode in KOH solutions under non-equilibrium conditions, which includes electrochemical as well as chemical crossed reactions between the different transient species.
Abstract: The square-type reaction scheme proposed to interpret the behaviour of the nickel hydroxide electrode in KOH solutions under non-equilibrium conditions must include electrochemical as well as chemical crossed reactions between the different transient species. These reactions are evidenced by means of the triangularly-modulated triangular potential sweep technique. The contribution of the crossed reactions in the square-type reaction scheme becomes more relevant as the KOH concentrations decreased in the presence of K2SO4 supporting electrolyte.
33 citations
TL;DR: In this article, the anodic chlorination of anisole on an α-cyclodextrin (α-CD) chemically modified electrode via ether linkage and a naked graphite electrode with α-CD or β-CD in solution was studied.
Abstract: The anodic chlorination of anisole on an α-cyclodextrin (α-CD) chemically modified electrode via ether linkage (α-CD-CME) and a naked graphite electrode with α-CD or β-CD in solution was studied. In the presence of CD, the p- to o-chloroanisole ratio, formed in the reaction, was higher than that in the absence of CD since o-positions of anisole included in CD are blocked by the inner wall of CD. Especially, α-CD had a profound effect on the p-isomer formation. Increasing the concentration of NaCl added as a supporting electrolyte in the presence of α-CD resulted in a decrease in the ratio because of the inhibition effect of chloride ion on the inclusion of anisole in α-CD, whereas such effect was small in the presence of β-CD. The ratio on α-CD-CME was slightly higher than that on the naked electrode. This indicates that α-CD was introduced on the graphite surface but the surface coverage of α-CD was low, which was in accord with the ESCA results of α-CD-CME.
24 citations
TL;DR: In this paper, the effect of different inorganic (HCl, H 2 SO 4, H 3 PO 4 ) and organic additives was studied for the simultaneous adsorption of Cl − ions and urea on platinized platinum electrodes under different experimental conditions.
21 citations
TL;DR: In the absence of an added proton donor, decomposition of the radical anions occurs by carbonhydrogen bond cleavage to give the conjugate bases of the starting materials; the anions subsequently slowly abstract a proton from the tetraalkylammonium cation of the supporting electrolyte to regenerate the original electroactive species as discussed by the authors.
21 citations
TL;DR: In this article, the diffusion coefficient of perhydroxyl ion (HO−2) was determined in 4.5 M LiOH supporting electrolyte and the experimental data were obtained chronoamperometrically used a rde.
18 citations
TL;DR: In this article, the role of electrosorption for the performance of four selected examples of electroorganic reactions is demonstrated, three of these reactions are anodic and the fourth is cathodic.
Abstract: Necessary conditions for the use of the influence of electrosorption on electrode kinetics, consecutive chemical kinetics and selectivity of electroorganic synthetic reactions are discussed. The role of electrosorption for the performance of four selected examples of electroorganic reactions is demonstrated. Three of these reactions are anodic and the fourth is cathodic. In the two cases of anodic formation of disaryliodonium cations and anodic oxidation of olefins, it is shown that the adsorptive character of the anode material is decisive for the success of the respective synthesis. For the first reaction, high current yields with only little loss of the precious iodoarene by formation of polymers, as well as avoidance of self coupling can only be obtained at Pt-anodes in acetonitrile. Anodic dimer formation by olefin oxidation only gives high yields at graphitic carbon anodes in methanol. Here semiquantitative data for electrosorption of olefins and supporting electrolyte anions have been obtained by electrode-kinetic measurements. They explain the influence of the supporting electrolyte anion on the dimer yield by the different spacial demands of the adsorbed anions of the supporting electrolyte. Due to very poor adsorption of radicals at Pt-anodes and strong radical adsorption at carbon-anodes, the anodic radical addition to olefins yields quite different product mixtures at these two anode materials. The optical inductive effect of electrosorbed strychninium cations on the cathodic reduction of acetylpyridine are shown to be caused by the enormous concentration enhancement of the alkaloid due to adsorption at the interphase. This is the precondition for complex formation between the negatively charged carbonation formed by disproportionation of the 1-e reduction product and the positively charged inductor cation. The preference of one of the two possible steroisomers is obtained only by this complex formation.
13 citations
TL;DR: In this paper, the mobility of adsorbed species, the potential dependence of the adsorption and the effect of different ions and organic species on the adorption were investigated in M HClO4 supporting electrolyte using platinized platinum electrode.
Abstract: The problem of the adsorption behaviour of succinic acid has been studied from different points of view. The mobility of adsorbed species, the potential dependence of the adsorption and the effect of different ions and organic species on the adsorption were investigated in M HClO4 supporting electrolyte using platinized platinum electrode. It has been stated that succinic acid does not chemisorb under the experimental conditions studied, and it may be considered as a typical representative of organic compounds which behave like anions with respect to the adsorption properties. An attempt was made to explain the unexpected potential dependence of the adsorption of these species.
12 citations
TL;DR: In this article, a new method for benzylic alkoxylation and hydroxylation of 3methoxy-estra-1,3,5(10)-trienes (I) was described.
TL;DR: In this paper, Coulometric methods for the determination of hydroquinone and 2-methylhydroquinone were reported, and the best results were obtained with 0.7-1.1 M potassium acetate solutions as supporting electrolyte, and biamperometric end-point detection.
TL;DR: In this article, the electrophoretic behavior of ten organic acids and four bases as model samples in water-methanol and water-ethanol has been studied with respect to the organic solvent concentration in the supporting electrolyte and its pH.
TL;DR: In this article, it was shown that the most positive pre-wave at −0.2 V and − 0.5 V are of nonfaradaic nature being related to the adsorption of the complex with specifically adsorbed anions of the supporting electrolyte with the formation of a compact adorbed layer of much lower interfacial capacity.
TL;DR: Theoretical calculations for the study of irreversible charge transfer reactions with the current-time function I(t)=I0t−1/2 are given in this article, where methods of determining the kinetic constants from the resulting potential-time functions are proposed.
TL;DR: In this article, the electrochemical reduction of allyl iodide, allyl bromide and allyl anion was studied in dry acetonitrile with TBAP as supporting electrolyte by means of cyclic voltammetry.
Abstract: The electrochemical reduction of allyl iodide ( la ) , allyl bromide ( l b ) , (E)-3-bromo-l-phenyl-l-propene (IC), and (E)-5-bromo-2,2,6,6-tetramethyl-3-heptene ( Id ) was studied in dry acetonitrile with TBAP as supporting electrolyte by means of cyclic voltammetry and coulometry at mercury, platinum, and vitreous carbon electrodes. Compounds la-c showed multiple waves on platinum and mercury because of halide surface effects. However on vitreous carbon la-d gave single reduction waves, with half-peak potentials of -1.38, -1.64, -1 .1 I , and -1.89 V (vs. SCE), respectively. Apparent coulometric n values of 1 for la-c were shown to arise from rapid nucleophilic substitution of the allyl anion intermediates with starting halide to give electroinactive dimers. Sterically hindered Id showed an napp of 2 and did not exhibit surface interactions with Hg and Pt. Thus allyl halides, contrary to previous statements in the literature, are reduced via a two-electron electrode reaction and the reduction of the allyl radical to the allyl anion cannot be seen as a separate step. Evidence was also obtained for the formation of the allyl anion by reduction of l a and I b with solvated electrons in liquid ammonia; the electrochemical oxidation of this species in this medium occurred at ca. -1.2 V.
TL;DR: Reflection spectroscopic studies have been carried out over a range of wave-lengths in the visible and near uv spectrum in an attempt to establish if the distinguisable states of H chemisorption have characteristic optical as well as electrochemical features.
TL;DR: In this article, the reduction mechanism at a mercury electrode of Eriochrome Cyanine R, in a 0.9 M NaClO4+0.1 M HClO 4 supporting electrolyte, has been investigated by several electrochemical techniques.
TL;DR: In this paper, the background currents for polythioxyl electrodes in 1 N H2SO4 supporting electrolyte were studied and it was shown that oxygen strongly chemisorbs on both parallel and perpendicular surfaces.
Abstract: Studies of the background currents for polythioxyl electrodes in 1 N H2SO4 supporting electrolyte shows that oxygen strongly chemisorbs on both parallel and perpendicular surfaces. On fresh surfaces the principle product on anodic breakdown is oxygen but on prolonged cycling surface hydroxides of (SN)x are the major surface functional groups at anodic breakdown.
TL;DR: In this paper, the results of preparation of benzil in DMF under various conditions are described, and the relative amounts of these products depend very much on the supporting electrolyte, the alkylating agent and its concentration.
01 Jan 1979
TL;DR: In this article, the kinetics of the [Fe(CN)6]3-/[Fe6]4- system was studied on rotating La1-xSrxCoO3-y disk electrodes (0.1 ≤ x ≤ 0.5) with 1 M NaOH as a supporting electrolyte.
Abstract: The kinetics of the [Fe(CN)6]3-/[Fe(CN)6]4- system was studied on rotating La1-xSrxCoO3-y disk electrodes (0.1 ≤ x ≤ 0.5) with 1 M NaOH as a supporting electrolyte. The electrochemical behaviour of this system on five compositions of the p-type semiconducting electrode materials deviates only slightly from its behaviour on Pt, i. e. no significant effect of the various oxide materials upon the redox kinetics is detectable.
Die Kinetik des [Fe(CN)6]3-/[Fe(CN)6]4--Systems wurde auf rotierenden La1-xSrxCoO3-y (0.1 ≤ x ≤ 0.5) -Scheibenelektroden untersucht. Es wurde 1 M NaOH als Tragerelektrolyt verwendet. Das elektrochemische Verhalten dieses redox-Systems auf funf Zusammensetzungen dieser halbleitenden Elektrodenmaterialien des p-Typs weicht nur geringfugig ab von dem Verhalten auf Pt. Keine bedeutenden spezifischen Einflusse der verschiedenen Oxydmaterialien auf die Kinetik des redox-Systems sind detektierbar.
TL;DR: In this article, a number of methods for the measurement of the corrosion rate of iron have been compared using a natural (unsupported) water and water supported with sodium perchlorate.
Abstract: A number of methods for the measurement of the corrosion rate of iron have been compared using a natural (unsupported) water and water supported with sodium perchlorate. All the methods gave similar results for the supported electrolytes and demonstrated the efficiency off our commercial corrosion inhibitors.Unsupported (dilute) electrolyte solutions could not be investigated by the faradaic impedance method using a simple bridge technique. Polarisation data from the dilute solutions gave misleading results due to the high resistance of the solution and the effect of the diffuse double layer.Sodium perchlorate appears to be a suitable supporting electrolyte for the electrochemical study of iron free from gross films of corrosion product in simple solutions.
TL;DR: In this article, Tetrathiafulvalene-tetracyanoquinodimethane (TTF-PCNQ) was used as an electrode in aqueous media and the electrode was stable over a potential range of about 0.9 V; within this region the electrode exhibited residual faradaic currents of less than 1-2 pA/cm2.
Abstract: Compacted pellets of tetrathiafulvalene-tetracyanoquinodimethane (TTF-PCNQ) were prepared and the proper- ties of this material as an electrode in aqueous media were investigated. The electrode was stable over a potential range of about 0.9 V; within this region the electrode exhibited residual faradaic currents of less than 1-2 pA/cm2 and the oxidation and reduction of soluble redox couples at this electrode could be carried out. Lpon exceeding the potential limits of stability of the electrode, the subsequent voltammograms showed symmetrical peaks attributable to insoluble compounds of TTF or TCNQ and supporting electrolyte ions (e.g.. TTFBr, KTCNQ). The redox reaction of these species could also be observed in the cyclic voltammograms
TL;DR: In this article, the differences in electrochemical behaviour of 3-nitropyridine and nitrobenzene connected with a change of supporting electrolyte are discussed, and it is shown that in the presence of alkaline earch metal cations a deposit of composition (NB−. Me2+) is formed at the electrode surface.
TL;DR: In this article, the electrooxidation of alicyclic bromides in acetonitrile has been investigated and the mechanism of formation of the products is discussed and the effect of concentration, temperature, supporting electrolyte, and amount of electricity consumed was studied in the oxidation of bromocyclohexane.
Abstract: The electro-oxidation of alicyclic bromides in acetonitrile has been investigated. Cycloheptyl, cyclohexyl, and cyclopentyl bromides each gave the corresponding N-cycloalkylacetamide and cycloalkene. Cyclobutyl bromide gave only N-cyclobutylacetamide whereas cyclopropyl bromide underwent ring-opening and yielded N-allylacetamide. The mechanism of formation of the products is discussed and the effect of concentration, temperature, supporting electrolyte, and amount of electricity consumed was studied in the oxidation of bromocyclohexane.
TL;DR: In this paper, a current maximum was observed by d.c. i−t curves during the drop life of a hanging mercury electrode in DMSO solutions, and the dependence of the streaming with depolarizer and supporting electrolyte concentration, as well as its independence of flux rate confirmed by linear sweep potential experiments, permit us to classify the streaming under study as a positive first kind streaming.
TL;DR: In this article, N, N′-dimethylformamide was used as solvent with a high degree of polarity, ammonium acetate solution as supporting electrolyte, and gelatin solution as maxima suppressor, to determine polarographically anthraquinone, aminoanthrasquinone and naphthaquinone after removing oxygen by bubbling the solution with an inert gas.
Abstract: N, N′-dimethylformamide was used as solvent with a high degree of polarity, ammonium acetate solution as supporting electrolyte, and gelatin solution as maxima suppressor, to determine polarographically anthraquinone, aminoanthraquinone, and naphthaquinone After removing oxygen by bubbling the solution with an inert gas, the mentioned compounds were reduced at different polarization potentials, giving 3 reduction steps relative to the mercury dropping electrode
TL;DR: In this paper, the effect of decreasing the supporting electrolyte concentration to a level at which it can no longer be considered to be in excess was investigated using the voltammetric technique of semi-integral electroanalysis.
Abstract: Using the voltammetric technique of semiintegral electroanalysis, a study has been made of the effect of decreasing the supporting electrolyte concentration to a level at which it can no longer be considered to be in excess. An imperfect theory predicts that, for the reduction of metal cations, the voltammetric signal under conditions of complete concentration polarization will exceed that in the presence of excess supporting electrolyte by the factor, where is the fraction of the ionic strength contributed by the electroactive ion, while and are the diffusion coefficients of the electroactive and supporting ions. Experiments on three systems have confirmed these predictions for ratios in the range 0–0.3.
TL;DR: Polarographic investigations of copper-chloramphenicol (Hf) complex were performed in 1 M NaCl which was used as the supporting electrolyte, at pH values from 11 to 13.