• Title/Summary/Keyword: Chemical reduction

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Photochemical Reduction of trans-1,2-Bispyrazylethylene (트란스-1,2-비스피라질에틸렌의 광화학적 환원)

  • Sang Chul Shim;Jeong Seok Chae
    • Journal of the Korean Chemical Society
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    • v.21 no.2
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    • pp.102-107
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    • 1977
  • Photochemical reduction of 1,2-bispyrazylethylene,a stilbene like heterocompound, was studied in hydrogen donating solvents and reduction product, 1, 2-bispyrazylethane, was identified. Salt and solvent effects on the quantum yields of the reduction, sensitization and quenching studies showed that the reactive state for the photochemical reduction of the compound is $(n,{\pi}^*)^1$ state rather than $({\pi},{\pi}^*)^1$ state.

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Effect of Different Pretreatments on Indium-Tin Oxide Electrodes

  • Choi, Moonjeong;Jo, Kyungmin;Yang, Haesik
    • Bulletin of the Korean Chemical Society
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    • v.34 no.2
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    • pp.421-425
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    • 2013
  • The effect of pretreatment on indium-tin oxide (ITO) electrodes has been rarely studied, although that on metal and carbon electrodes has been enormously done. The electrochemical and surface properties of ITO electrodes are investigated after 6 different pretreatments. The electrochemical behaviors for oxygen reduction, $Ru(NH_3){_6}^{3+}$ reduction, $Fe(CN){_6}^{3-}$ reduction, and p-hydroquinone oxidation are compared, and the surface roughness, hydrophilicity, and surface chemical composition are also compared. Oxygen reduction, $Fe(CN){_6}^{3-}$ reduction, and p-hydroquinone oxidation are highly affected by the type of the pretreatment, whereas $Ru(NH_3){_6}^{3+}$ reduction is almost independent of it. Interestingly, oxygen reduction is significantly suppressed by the treatment in an HCl solution. The changes in surface roughness and composition are not high after each pretreatment, but the change in contact angle is substantial in some pretreatments.

Synthesis of Ag-Pd Alloy Nanoparticles by Chemical Reduction Method (화학환원법을 이용한 Ag-Pd 합금 나노분말의 합성)

  • Seo, Won-Sik;Kim, Yun-Do;Choung, Il-Yeop;Lee, Ho-Seok;Song, Ki-Chang
    • Journal of the Korean Ceramic Society
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    • v.43 no.4 s.287
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    • pp.224-229
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    • 2006
  • Ag-Pd alloy nanoparticles were prepared by a chemical reduction method using hydrazine $(N_2H_4)$ as a reductant in $AgNO_3\;and\;Pd(NO_3)_2$ aqueous solutions. Characterization of these particles by X-ray powder diffraction revealed a bimetallic and crystalline silver-palladium alloy. The average size of the particles was influenced not by the reductant $(N_2H_4)$ concentration, but the concentration of the starting materials $(AgNO_3\;and\;Pd(NO_3)_2)$.

Preparation of Copper Nanoparticles and Catalytic Properties for the Reduction of Aromatic Nitro Compounds

  • Duan, Zhongyu;Ma, Guoli;Zhang, Wenjun
    • Bulletin of the Korean Chemical Society
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    • v.33 no.12
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    • pp.4003-4006
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    • 2012
  • A novel copper nanoparticles were synthesized from cupric sulfate using hydrazine as reducing reagents. A series of aromatic nitro compounds were reacted with sodium borohydride in the presence of the copper nanoparticles catalysts to afford the aromatic amino compounds in high yields. Additionally, the catalysts system can be recycled and maintain a high catalytic effect in the reduction of aromatic nitro compounds.

Preparation and Characterization of Palladium Nanoparticles Supported on Nickel Hexacyanoferrate for Fuel Cell Application

  • Choi, Kwang-Hyun;Shokouhimehr, Mohammadreza;Kang, Yun Sik;Chung, Dong Young;Chung, Young-Hoon;Ahn, Minjeh;Sung, Yung-Eun
    • Bulletin of the Korean Chemical Society
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    • v.34 no.4
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    • pp.1195-1198
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    • 2013
  • Nickel hexacyanoferrate supported palladium nanoparticles (Pd-NiHCF NPs) were synthesized and studied for oxygen reduction reactions in direct methanol fuel cell. The NiHCF support was readily synthesized by a comixing of $Ni(OCOCH_3)_2$ and equimolar $K_3[Fe(CN)_6]$ solution into DI water under rigorous stirring. After the preparation of NiHCF support, Pd NPs were loaded on NiHCF via L-ascorbic acid reduction method at $80^{\circ}C$. Pd-NiHCF NPs were electrochemically active for oxygen reduction reaction in 0.1 M $HClO_4$ solution. X-ray absorption near edge structure analysis was conducted to measure the white line intensity of Pd-NiHCF to verify the OH adsorption. As a comparison, carbon supported Pd NPs exhibited same white line intensity. This study provides a general synthetic approach to easily load Pd NPs on porous coordination polymers such as NiHCF and can provide further light to load Pd based alloy NPs on NiHCF framework.

Electrochemical Reduction of Triphenylphosphine Phenylimide (Triphenylphosphine Phenylimide의 전기화학적인 환원)

  • Pak Chong Min;Wilson M. Gulick, Jr.
    • Journal of the Korean Chemical Society
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    • v.18 no.5
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    • pp.341-353
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    • 1974
  • The electrochemical reduction of triphenylphosphine penylimide in nonaqueous media has been examined by polarography, cyclic voltammetry, controlled-potential coulometry and electron spin resonance spectroscopy. The reduction of triphenylphosphine phenylimide proceeds by a one-electron transfer to form anion radical which undergoes both protonation and a second one-electron reduction followed by cleavage of the phosphorus-nitrogen double bond. Aniline is a major product. The cleavage of a phosphorus-phenyl bond was also observed after reduction of triphenylphosphine oxide which is one of the major products of the chemical reaction which follow the primary process.

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Selective Reduction of Oximes to N-Monosubstituted Hydroxylamines with Lithium Borohydride

  • Cho, Byung-Tae;Seong, See-Yearl
    • Bulletin of the Korean Chemical Society
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    • v.9 no.5
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    • pp.322-324
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    • 1988
  • Selective reduction of aldoximes and ketoximes with lithium borohydride in tetrahydrofuran was investigated. Thus, aldoximes and cyclic ketoximes such as hexanaldoxime, heptanaldoxime, cyclopentanone oxime and cyclohexanone oxime were reduced smoothly to the corresponding N-monosubstituted hydroxylamines at room temperature in 65-93% yield. The reduction of alicyclic ketoxime was very slow, requiring somewhat high reaction temperature ($65^{\circ}C$) for the complete reduction to give the hydroxnylamines. The reduction of aromatic oximes such as benzaldoxime and acetophenone oxime was very sluggish, giving a mixture of the corresponding hydroxylamines and amines at $65^{\circ}C$.