• Bulletin of the Korean Chemical Society
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• v.35 no.4
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• pp.1233-1236
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• 2014

• Bulletin of the Korean Chemical Society
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• v.31 no.12
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• pp.3852-3855
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• 2010

• Bulletin of the Korean Chemical Society
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• v.11 no.2
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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.

• Bulletin of the Korean Chemical Society
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• v.20 no.1
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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.

• Bulletin of the Korean Chemical Society
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• v.18 no.10
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• pp.1100-1104
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• 1997

Compounds containing a nitrone moiety were designed, synthesized and evaluated as a new type of active site zinc ligating substrate analog inhibitors for carboxypeptidase A. The kinetic results indicated that they are competitive inhibitors for the enzyme, supporting the design rationale that the oxygen of the nitrone forms a coordinative bond to the active site zinc ion. The present study demonstrates that nitrone is useful as a zinc coordinating ligand in the design of inhibitors for zinc containing proteolytic enzymes.

• Bulletin of the Korean Chemical Society
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• v.5 no.6
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• pp.211-215
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• 1984

Reaction of thianthrene cation radical perchlorate (1) with tert-butyl peroxide (TBP) in acetonitrile gave thianthrene (2), thianthrene 5-oxide (3), cis-thianthrene-5,10-dioxide (4), 5-acetonylthianthrenium perchlorate (9), along with small amount of thianthrene-5,5-dioxide (7) in some cases. Isolation of N-tert-butylacetamide indicated the formation of tert-butyl cation from TBP. The formation mechanisms of these products were proposed.

• Korean Journal of Weed Science
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• v.30 no.2
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• pp.143-152
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• 2010

Herbicidal characterisitcs of natural product chrysophanic acid were investigated in a greenhouse condition. At early- and middle-stage post-emergence treatments, several grasses and broadleaf weeds appeared to be very susceptible to chrysophanic acid. However, any significant herbicidal activity treated by pre-emergence did not occur at concentration ranges from 31.3 to 1,000 ug $mL^{-1}$. Herbicidal activity of chrysophanic acid estimated by visual injury for large crabgrass was much higher when applied at 7 to 14 days after seeding than at 21 and 28 days after seeding. By post-emergence treatment, chrysophanic acid caused very considerable phytotoxicity on several grasses and broadleaf crops. In herbicidal interaction experiments determined by Colby's method, the effect of chrysophanic acid and caryophyllene oxide tank-mixture showed very high synergistic activity. Although chrysophanic acid did not give any pre-emergence effect, herbicidal spectrum tended to be very wide and strong when treated by post-emergence. These results suggest that chrysophanic acid possesses a possible potential to develop as a natural herbicide.

• Bulletin of the Korean Chemical Society
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• v.28 no.11
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• pp.2089-2092
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• 2007

Tantalum-containing metal oxides, well known for their efficiency in water splitting and H2 production, have never been used in visible light driven photodecomposition of H2S and H2 production. The present work is an attempt in this direction and investigates their efficiency. A mixed metal oxide, ZnFe2Ta2O9, with the inclusion of Fe2O3 to impart color, was prepared by the conventional ceramic route in single- and double-calcinations (represented as ZnFe2Ta2O9-SC and ZnFe2Ta2O9-DC respectively). The XRD characterization shows that both have identical patterns and reveals tetragonal structure to a major extent and a minor contribution of orthorhombic crystalline system. The UV-visible diffuse reflection spectra demonstrate the intense, coherent and wide absorption of visible light by both the catalysts, with absorption edge at 650 nm, giving rise to a band gap of 1.9 eV. Between the two catalysts, however, ZnFe2Ta2O9-DC has greater absorption in almost the entire wavelength region, which accounts for its strong brown coloration than ZnFe2Ta2O9-SC when viewed by the naked eye. In photocatalysis, both catalysts decompose H2S under visible light irradiation (λ ≥ 420 nm) and produce solar H2 at a much higher rate than previously reported catalysts. Nevertheless, ZnFe2Ta2O9-DC distinguishes itself from ZnFe2Ta2O9-SC by exhibiting a higher efficiency because of its greater light absorption. Altogether, the tantalum-containing mixed metal oxide proves its efficient catalytic role in H2S decomposition and H2 production process also.

• Journal of Hydrogen and New Energy
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• v.17 no.1
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• pp.55-61
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• 2006

신규 $Nb_2Zr_6O_{17-x}N_x$ 광촉매를 고상합성법처리(solid state synthesis) 후 암모니아가스($NH_3$)에 의한 기상처리법(ammonolysis)으로 합성하였다. 합성된 신규 광촉매 및 이를 다시 Pt 및 $RuO_2$를 도핑 하여 $H_2S$를 광분해하여 수소를 발생 실험을 수행하였다. 이 신규 oxynitrid계 광촉매는 가시광하에서 $H_2S$를 광분해하여 수소를 발생하는(Quantum yield = 13.5 %) 우수한 광촉매 활성을 보여주었다.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.1
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• pp.1-7
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• 2005

Thin films of vanadium oxide(VO/sub x/) were deposited by r.f. magnetron sputtering from V₂O/sub 5/ target with oxygen/(oxygen+argon) partial pressure ratio of 0% and 8% and in situ annealed in vacuum at 400℃ for 1h and 4h. Crystal structure, chemical composition, molecular structure, optical and electrical properties of films were characterized through XRD, XPS, RBS, FTIR, optical absorption and electrical conductivity measurements. The films as-deposited are amorphous, but 0%O₂ films annealed for time longer than 4h and 8% O₂ films annealed for time longer than 1h are polycrystalline. As the oxygen partial pressure is increased the films become more stoichiometric V₂O/sub 5/. When annealed at 400℃, the as-deposited films are reduced to a lower oxide. The optical transmission of the films annealed in vacuum decreases considerably than the as-deposited films and the optical absorption of all the films increases rapidly at wavelength shorter than about 550nm. Electrical conductivity and thermal activation energy are increased with increasing the annealing time and with decreasing the oxygen partial pressure.