• 제목/요약/키워드: acidic chemical

검색결과 916건 처리시간 0.032초

Inhibitor에 關한 硏究 (Studies on Corrosion Inhibitors)

  • 이계수
    • 대한화학회지
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    • 제13권1호
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    • pp.13-15
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    • 1969
  • This investigation is to make comparative evaluation of the corrosion inhibiting effects of quinoline, oxine and 7-nitroso 8-hydroxy quinoline (7NHQ). In case of quinoline, and oxine, since the N atom in them functions as cation, the process involved is assumed to be cathode control. On the other hand 7-NHQ was found to form a stable chelate compound with $Fe^{++}$ ion in acidic solution and shows as anode control predominantly. After plotting polarization curves, Tafel parameters were calculated in each solution involving the inhibitors, at the same time corrosion inhibiting effects were separately measured and compared from data of both corrosion current and analytical method.

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Montmorillonite KSF Clay as Novel and Recyclable Heterogeneous Catalyst for the Microwave Mediated Synthesis of Indan-1,3-Diones

  • Marvi, Omid;Giahi, Masoud
    • Bulletin of the Korean Chemical Society
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    • 제30권12호
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    • pp.2918-2920
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    • 2009
  • Various indan-1,3-dione derivatives were synthesized from the reaction of different phthalic anhydrides with diethylmalonate using montmorillonite KSF clay as a recyclable heterogeneous acidic catalyst and microwave irradiation in good yields and short reaction times.

Electrochemical and Spectrophotometric Studies on Polyaniline and its Degradation

  • Jung-Kyoon Chon;Byung-Hoon Min;Woon-Kie Paik
    • Bulletin of the Korean Chemical Society
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    • 제11권2호
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    • pp.105-108
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    • 1990
  • A spectroelectrochemical study on the redox chemistry of polyaniline (PANI) was carried out by using indium-tin oxide (ITO) transparent electrode in aqueous acidic solutions. Three different PANI-derived species were observed depending on the potential. The most highly oxidized species having alternating benzenoid-quinoid structures degraded through hydrolysis reaction. The degradation products were confirmed to be p-benzoquinone (BQ) and p-diaminobenzene (PDAB) by spectrophotometry anld potentiostatic experiments. Finally, a degradation mechanism is deduced from the observed behaviour.

Oxidations of Cyclohexanols by N-Bromosuccinimide and Sodium Hypochlorite

  • Chung, Kyoo-Hyun;Kim, Seong-Jin
    • Bulletin of the Korean Chemical Society
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    • 제7권2호
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    • pp.111-113
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    • 1986
  • The axial alcohol in trans-3,3,5-trimethylcyclohexanol was oxidized more readily than the equatorial alcohol in cis-3,3,5-trimethylcyclohexanol by NBS in aqueous dioxane. On the contrary, the equatorial alcohol was preferentially oxidized to the axial one by 10% aqueous sodium hypochlorite in the presence of tetrabutylammonium hydrogen sulfate (TBHS). The specificity indicates the presence of two different mechanism. In acidic medium, the cleavage of C-H bond is rate determining step while the reactivity of the alcohol is important in the presence of TBHS. The mechanism in basic medium without TBHS will be discussed.

Gif-KRICT Biomimetic Oxidation of Cyclohexane: The Influence of Metal Oxides

  • 박애숙;남상성;김성보;이규완
    • Bulletin of the Korean Chemical Society
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    • 제20권1호
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    • pp.49-52
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    • 1999
  • Various metal oxides such as Fe2O3, FeO, TiO2, MnO2, MoO3, WO3 and ZnO have been used as a catalyst for Gif-KRICT type cyclohexane oxidation. In this reaction, the conversion of cyclohexane to cyclohexanone and cyclohexanol and the selectivity ratio of cyclohexanone to cyclohexanol were greatly affected by the acidity of metal oxides. When metal oxide has more acidic property, the reactivity on oxidation is increased and the formation of cyclohexanone is more favored. From this result, we proposed a new mechanism for the biomimetic Gif-KRICT oxidation system.

Intercalation of Functional Organic Molecules with Pharmaceutical, Cosmeceutical and Nutraceutical Functions into Layered Double Hydroxides and Zinc Basic Salts

  • 황성호;한양수;최진호
    • Bulletin of the Korean Chemical Society
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    • 제22권9호
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    • pp.1019-1022
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    • 2001
  • Negatively charged functional organic molecules such as retinoic acid, ascorbic acid, indole acetic acid, citric acid, salicylic acid, acidic dye (indigo carmine, Food Blue 1) are intercalatively encapsulated by zinc basic salt (hydrozincite) and layered double hydroxide. Such functional organic-inorganic nanohybrids are realized via coprecipitation reaction involving simultaneous formation of layered inorganic lattice and intercalation of anionic species. The heterostructural nature of these nanohybrids, their particle morphology and textural characterizations are mainly discussed on the basis of Powder X-ray Diffraction and Field Emission Scanning Electron Microscopy results.

Reaction Conditions and Mechanism of Electrolytic Reduction of Dibenzoylmethane$^\dag$

  • Kang, Sung-Chul;Chon, Jung-Kyoon
    • Bulletin of the Korean Chemical Society
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    • 제8권5호
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    • pp.414-418
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    • 1987
  • Electrochemical reduction of dibenzoylmethane was studied on mercury electrode by means of cyclic voltammetry, polarography and potentiostatic measurements in ethanol-water system. In acidic solutions monomeric pinacol was produced by irreversible two-electron process while monomeric and dimeric pinacol were competitively produced by the same process in neutral solution. However, in basic solution the dimeric pinacol was mostly produced through radical by irreversible one-electron transfer process. Mechanisms of the reduction of dibenzoylmethane are deduced from Tafel slope, pH dependance and reaction order with respect to the concentration of dibenzoylmethane in the solution of various pH.