• Journal of the Korean Chemical Society
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• v.19 no.2
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• pp.104-115
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• 1975

The electrochemical reduction of iodine in non-aqueous media have been studied by polarography, chronopotentiometry, cyclic voltammetry and controlled potential coulometry at dropping mercury electrode and platinum, gold and amalgamated platium electrodes. In amphiprotic solvents such as methanol, ethanol, isopropanol and pyridine, iodine were reduced to iodide ions via one step reduction involving 1 electron and in aprotic solvents such as acetonitrile, dimethylformamide and dimethylsulfoxide via two step reduction involving all 3 electrons. The reductions of iodine give well defined polarograms at dropping mercury electrode and irreversible chronopotentiograms at platinum electrode, but less defined irreversible chronopotentiograms at gold and amalgamated platinum electrodes, those are all diffusion controlled. The diffusion coefficients of iodine in various solvents were estimated from the chronopotentiometric data and Sand equation.

• Journal of the Korean Chemical Society
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• v.35 no.1
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• pp.70-77
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• 1991

1-Benzyl-4-iodomethyl-2-azetidinone(BIMA) was synthesized and its electrochemical reduction was investigated by direct current, differential pulse polarography, cyclic voltammetry and controlled potential coulometry. The irreversible two electron transfer on reductive dehalogenation of iodo group proceeded to form 1-benzyl-4-methyl-2-azetidinone by EEC electrode reaction mechanism at the first reduction step(-1.35 volts vs. Ag-AgCl). The polarographic reduction waves separated into two reduction steps due to anionic surfactant (sodium lauryl sulfate) effects, while the waves were shifted to the positive potential as the concentration of cationic surfactant (cetyltrimethylammonium bromide) increased. Upon the basis of results on the product analysis and interpretation of polarogram with pH variable, EEC electrochemical reaction mechanism was suggested.

• Bulletin of the Korean Chemical Society
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• v.11 no.6
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• pp.521-527
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• 1990

The binding characteristics and analytical applications of anilinium ion complexes with 18-crown-6 were studied by polarography and NMR. First, the electrochemical reduction of the 10 species of mono and dimethylsubstituted anilinium ion complexes with 18-crown-6 as host in methanol are examined. The addition of 18-crown-6 to anilinium guest solution the polarographic waves remain well defined but shifted toward more negative potentials, indicating the complex formation. The values of formation constants, log Κ for 10 species of methylsubstituted anilinium ion complexes with 18-crown-6 varies from 2.7 to 4.8 in methanol at $25^{\circ}C$. The stability order of complexes for 18-crown-6 is anilinilum > 4-methyl > 3,4-dimethyl > 3-methyl > 3,5-dimethyl > 2,4-dimethyl > 2,5-dimethyl > 2,3-dimethyl > 2-methyl > 2,6-dimethylanilinium ion. The steric hindrance shows significant effect. Second, Proton NMR was used to elucidate their interaction characteristics. From the results of so called NMR titration techniques, the behaviors of binding sites on complexation, and the stoichiometry and stability order of complex were obtained. And the later results show the satisfactory agreement with the quantitative values obtained by polarography. Finally, the individual determinations of anilinium ion mixtures were also accomplished by addition of 18-crown-6. In some mixtures of methyl or dimethylanilinium ions the reduction peaks of differential pulse method appeared into one unresolved wave attributed to the small difference of half-wave potential, ${\Delta}E_{1/2}$. In the presence of 18-crown-6, the polarographic waves were resolved into individual maxima because of the shift toward more negative direction by the difference of selectivity of anilinium ions with 18-crown-6. It may be concluded that quantitative analysis of methylanilinium ion mixture make possible because the half-wave potential shift by the selectivity difference due to the steric hindrance between methyl group and 18-crown-6 on complexation.

• Journal of the Korean Chemical Society
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• v.28 no.2
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• pp.130-134
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• 1984

The polarographic behavior of benzeneazoresorcinol (BAR) in acetonitrile as an aprotic solvent has been investigated by direct current polarography and controlled-potential coulometry. The reduction of BAR in $1.0{\times}10^{-2}$M tetraethylammonium perchrolate solution proceeds along four one-electron steps to give the corresponding amine compounds. Each reduction wave was considerably diffusion-controlled and not completely reversible.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.10 no.S_4
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• pp.173-179
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• 2001

The chemical behavior and properties of the redox state of environmental pollutants was investigated using electrochemical methods. The purpose was to measure the variations in the redox reaction of differential pulse polarograms and cyclic voltammograms. The results observed the influences on redox potential and current of various factors including concentration, temperature, salt, and pH. These were established factors as the effect of the redox reaction. It can be clearly recognized that the electrode reaction are from reversible to irreversible processes. Also, it was mixing with reaction current controlled.

• Journal of the Korean Chemical Society
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• v.13 no.4
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• pp.303-307
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• 1969

The ammonium salt of Nitrosophenylhydroxylamine "called cupferron", is a well-known analytical reagent, which precipitates a great number of metal ions in acid medium. The electrode reduction velocities of cupferron at droping mercury electrode in various supporting electrolytes were measured by Delahay method. The free energy of activation and transfer coefficient for a given electrode reaction are computed from the corresponding current-voltage curve. The number of electrons involved in the rate determining step of the reduction of cupferron is calculated for solutions of various pH.

• Journal of the Korean Chemical Society
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• v.34 no.3
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• pp.280-287
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• 1990

The electrochemical behavir of trivalent lanthanides [Sm(Ⅲ), Tb(Ⅲ), and Yb(Ⅲ)) complexes were investigated by the use of direct current, differential pulse polarography and cyclic voltammetry in aprotic media. These reduction peak were irreversible one-electron processes at $E_{pc}$ = -0.16 V, -0.35 V, -0.14 V, and -0.03 V of trivalent lanthanide complexes vs. Ag/AgCl electrode and the behavior of heavier lanthanides were decreased Sm > Tb > Ho > Yb order of the stability constant with decreasing atomic number.

• Journal of the Korean Chemical Society
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• v.6 no.1
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• pp.61-63
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• 1962

The polarographic behaviors of Tl(I) was investigated in EDTA and NTA as supporting electrolytes for determination of Tl(I). A base solution containing 0.005 % gelatine, 0.1 M EDTA, and 0.05 M NTA was used. The halfwave potential of Tl(I) determined is -0.495 V v.s. S.C.E. in 0.1 M EDTA at pH 4.1 and -0.520V v.s. S.C.E. in 0.05 M NTA at pH 6.3. In this paper, the effects of gelatine concentration and pH values was investigated. The half-wave potentials of common elements was determined and compared with the half-wave potential of Tl(I).

• Journal of the Korean Chemical Society
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• v.9 no.2
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• pp.71-74
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• 1965

Reduction of Ti(Ⅳ)-oxalate complex on dropping mercury electrode has been studied as a function of oxalate concentration and of pH varied with HCl. Assuming there are equilibrium $TiO(C_2O_4)_2= \;+\;2H^+\;=\;Ti^{+4}\;+\;2C_2O_4\;=\;+\;H_2O,\;K_4$ in addition to $TiO(C_2O_4)_2\;^=\;=\;TiO^{++}\;+\;2C_2O_4=\;K_2\;Ti(C_2O_4)_2\;^-\;=\;Ti^{+3}\;+\;2C_2O_4=\;K_3$ in the system cathodic wave has been well explained for that pH is higher than 0.5. The equilibrium constants $K_2,\;K_3$ and $K_4$ have been to be $2{\times}10^{-12},\;5{\times}10^{-13}$ and $10^{-11}$, respectively. The reduction of Ti(Ⅳ)-oxalate system is $Ti^{+4}\;+\;e\;{\to}\;Ti^{+3}$ in the concentration of hydrochloric acid, higher than 3M.

• Journal of Environmental Science International
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• v.11 no.2
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• pp.131-137
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• 2002

The chemical behavior and properties on the redox state of environmental pollutant has been investigated by electrochemical methods. We carried out to measure the variations in the redox reaction of differential pulse polarogram and cyclic voltammogram. The results observed the influences on redox potential and current of various factors with temperature and pH. These were established factors as the effect of the redox reaction. It can be clearly recognized that the electrode reaction are from qusi-reversible to irreversible processes. Also, it was mixing with reaction current controlled. The bits-phenol A in the waste water was made to compound with cobalt ion and it take away from the separation into compound. The $Co(BPA)_2$ compound was not found to be dissociation in waste water. However, this compound is avery unstable(K=1.02) and for a while, it was to be a dissociation. Therefore, we believed that it was likely to a toxic substance.