Chloride-containing supporting electrolytes

Polarization Curves for Co-Ni Alloy Powder Electrodeposition from the Chloride-Containing Supporting Electrolyte... 

Chemical composition of aU electrodeposited Co-Ni alloy powders was determined by the AAS technique after dissolving certain amount of powders in HCl. The compositions of powders electrodeposited from sulfate and chloride containing supporting electrolytes were different. 

The same dependences as in Fig. 5.5 are presented in Fig. 5.6 for chloride containing supporting electrolyte. In this case anomalous codeposition is obtained for all Co-Ni alloy powders compositions, with the more noble metal electrodeposition (Ni) being suppressed by the presence of the less noble metal (Co) in the solution, i.e., less noble metal is more readily deposited. 

The carbon-nitrile bond in cyanoalkanes is cleaved by reduction at very negative potentials. This is the route for decomposition of acetonitrile at tlie limit for its use as an aprotic solvent in electrochemistry [114, 115]. Preparative scale reduction of cyanoalkanes is best carried out in anhydrous ethylamine containing lithium chloride as supporting electrolyte and gives 60-80 % yields of the alkane plus cyanide ion. 

Electrolytic preparation of sym-triazines has been reported electrolysis at a mercury cathode of N,AT-dimethylcyanamide (45) containing lithium chloride as supporting electrolyte produced... 

A number of 1,1-dihalocyclopropanes have been reduced electrochemically to monohalides using a mercury cathode in an appropriate solvent containing a supporting electrolyte, e.g. reduction of 38 (Table 4)112,130 ggg j.gj-g 128-130, 132, 133, 745, 758), but few reactions have been carried out on a preparative scale. One exception is 9,9-dibromobicyclo[6.1.0]nonane which is converted stereospecifically to exo-9-bromobicyclo[6.1.0]nonane (39) in better than 80% yield at a mercury cathode at 0°C using methanol as solvent and lithium chloride as supporting electrolyte. A reaction resulting in 17% asymmetric yield is described in ref 886. 

The polarization curves corrected for IR drop for the processes of Fe, Ni, and Fe-Ni alloy powder electrodeposition from ammonium chloride-sodium citrate containing supporting electrolyte in the presence of Fe(ll) and Ni(II) species are shown in Fig. 8.14. In the case of Fe(II) salts, polarization curve for iron electrodeposition (Fe) was placed at more positive potentials than that for nickel (Ni) as it is expected from the values of their reversible potentials. The polarization curves for Fe-Ni alloy powder electrodeposition are placed in between, and all of them were placed at more positive potentials than expected from the Ni/Fe ratio, indicating anomalous codeposition. 

The polarization curves corrected for IR drop for the processes of pure cobalt (Co), pure nickel (Ni), and Co-Ni aUoy (powders) electrodeposition from ammonium chloride-ammonium hydroxide containing supporting electrolyte are presented in Fig. 5.3 (in this case the total concentration of cations in aU investigated solutions was 0.1 M). As can be seen, cobalt electrodeposition (Co) commences at about —1.1 V, while sharp increase of current density (massive Co... 

Oxygen derivatives. A methanol-benzene (1 1) mixture containing 0-3 M lithium chloride as supporting electrolyte, was first... 

Note. The reduction current at —0-27 V can be corrected for the dissolved pentaerythritol tetranitrate from a curve obtained with a saturated solution. From a comparison of the currents obtained in nitrate and chloride media, the concentrations of pentaerythritol tetranitrate and nitroglycerine can be computed. The wave in chloride media is better suited to the determination of cyclotrimethylenetrinitramine, than that observed in nitrate-containing supporting electrolyte. 

Pipette lOmL of a cadmium sulphate solution (1.0gCd2+ L-1) into a 100 mL graduated flask, add 2,5 mL of 0.2 per cent gelatin solution, 50 mL of 2 M potassium chloride solution and dilute to the mark. The resulting solution (A) will contain 0.100gCd2+ L-1 in a base solution (supporting electrolyte) of 1 M potassium chloride with 0.005 per cent gelatin solution as suppressor. 

The redox equilibria can be considerably shifted by the presence of additional donor units. Thus the redox potential in a donor solvent will be influenced by the presence of anions and it may be different for a metal chloride and a metal iodide. The effect becomes more pronounced if the supporting electrolyte contains anions which have donor properties. Such donor anions will compete with solvent molecules for coordination. 

I. 4-methoxyacetophenone (30 //moles) was added as an internal standard. The reaction was stopped after 2 hours by partitioning the mixture between methylene chloride and saturated sodium bicarbonate solution. The aqueous layer was twice extracted with methylene chloride and the extracts combined. The products were analyzed by GC after acetylation with excess 1 1 acetic anhydride/pyridine for 24 hours at room temperature. The oxidations of anisyl alcohol, in the presence of veratryl alcohol or 1,4-dimethoxybenzene, were performed as indicated in Table III and IV in 6 ml of phosphate buffer (pH 3.0). Other conditions were the same as for the oxidation of veratryl alcohol described above. TDCSPPFeCl remaining after the reaction was estimated from its Soret band absorption before and after the reaction. For the decolorization of Poly B-411 (IV) by TDCSPPFeCl and mCPBA, 25 //moles of mCPBA were added to 25 ml 0.05% Poly B-411 containing 0.01 //moles TDCSPPFeCl, 25 //moles of manganese sulfate and 1.5 mmoles of lactic acid buffered at pH 4.5. The decolorization of Poly B-411 was followed by the decrease in absorption at 596 nm. For the electrochemical decolorization of Poly B-411 in the presence of veratryl alcohol, a two-compartment cell was used. A glassy carbon plate was used as the anode, a platinum plate as the auxiliary electrode, and a silver wire as the reference electrode. The potential was controlled at 0.900 V. Poly B-411 (50 ml, 0.005%) in pH 3 buffer was added to the anode compartment and pH 3 buffer was added to the cathode compartment to the same level. The decolorization of Poly B-411 was followed by the change in absorbance at 596 nm and the simultaneous oxidation of veratryl alcohol was followed at 310 nm. The same electrochemical apparatus was used for the decolorization of Poly B-411 adsorbed onto filter paper. Tetrabutylammonium perchlorate (TBAP) was used as supporting electrolyte when methylene chloride was the solvent. 

Charges of anionic species of phosphorus oxoacids were determined by an ion-exchange equilibrium method. For this purpose distribution ratios, D, of phosphorus oxoacid between an anion-exchange resin Dowex 1x4 phase and an aqueous solution phase containing tetramethylammonium chloride as a supporting electrolyte were obtained from the absorbancies of phosphorus oxoacid in the aqueous solution phase before and after equilibration. D was defined as the ratio of the concentration of phosphorus in the resin phase to the concentration of phosphorus in the solution phase. 

An important specialized type of voltammetric system is a self-contained cell for the determination of 02 in the gas or solution phases. This is the so-called Clark electrode,66,67 which consists of a platinum or gold electrode in the end of a support rod that is covered by an 02 permeable membrane (polyethylene or Teflon) such that a thin film of electrolyte is contained between the electrode surface and the membrane. A concentric tube provides the support for the membrane and the means to contain an electrolyte solution in contact with a silver-silver chloride reference electrode. The Clark device has found extensive application to monitor 02 partial pressure in blood, the atmosphere, and in sewage plants. By appropriate adjustment of the applied potential it gives a voltammetric current plateau that is directly proportional to the 02 partial pressure. The membrane material prevents interference from electroactive ions as well as from surface-contaminating biological materials. Figure 3.19 illustrates one configuration for this important device. 

---