• Applied Chemistry for Engineering
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• v.7 no.2
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• pp.326-333
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• 1996

Dehydrogenation of 4-vinylcyclohexene(4-VCH) to ethylbenzene is elucidated via catalytic transfer hydrogenation with the heterogeneous catalyst of Pd/C. Hydrogen-donor solvent is ethanol or water. Oxidizers of the catalytic dehydrogenation reaction are mono- or dinitro compounds, $H_2O_2$, NaClOn (n=1~4), or oxygen at $70{\sim}110^{\circ}C$. The ratio of 4-VCH/Nitro compounds is 1:0.02 to 1:0.5 and 4-VCH vs. $H_2O_2$ or NaClOn (n=1~4) is 1:0.1 to 1:3.

• Journal of the Korean Chemical Society
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• v.41 no.12
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• pp.661-665
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• 1997

Recently ADN was disclosed to replace AP or AN as a solid oxidizer. 3-N,N-Dinitraminopropanitrile, a key intermediate in the preparation of ADN, was synthesized from bis(2-cyanoethyl)amine by the sequence: nitration of bis(2-cyanoethyl)amine followed by decyanoethylation by base and the second nitration with NO2BF4. 3-N-Nitro-bis(2-cyanoethyl)amine could also be obtained by the oxidation of the corresponding N-nitroso compound.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2003.05a
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• pp.297-302
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• 2003

국내 화학공업에 있어서 두드러진 특징중의 하나는 의약품, 염·안료 등과 같은 부가가치가 매우 큰 제품을 제조하는 정밀화학공업이 대부분을 차지하고 있으며, 반응기는 회분식으로 대상이 되는 공정의 반응조건 등을 제조자 스스로 결정해야 하는 것이 많아 오조작이나 열분해반응이나 폭주반응과 같은 이상반응 발생 시 조기 제어 미흡 등으로 인한 화재 폭발 등 중대사고가 발생할 위험성이 매우 크다. 실제로 회분식 반응기에 의한 사고가 빈번히 발생하였고 사고에 의한 피해도 심각하다.(중략)

• Journal of the Korean Chemical Society
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• v.21 no.6
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• pp.404-412
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• 1977

Electrochemical reduction of nitrobenzene (${\phi}NO_2$) and its derivatives on Pb electrode was studied by means of galvanostatic measurements and coulometric electrolysis in ethanol-water solvent. In acidic solutions phenylhydroxyl amine and aniline ethanol-water solvent. In acidic solutions phenylhydroxyl amine and aniline were produced while nitrosobenzene and coupled products such as azo-and hydrazobenzene were produced in basic solutions. Nitrosobenzene (${\phi}NO$) was not found to be an intermediate in the reduction reactions of ${\phi}NO_2$ in acidic solutions. No direct coupling between ${\phi}NO\;and\;{\phi}NHOH$ was observed to occur in the electrolyte solutions used. Mechanisms of the production of phenylhydroxylamine and nitrosobenzene are deduced from Tafel slope, pH dependence and reaction order with respect to nitrobenzene. Mechanism for the reduction of substituted nitrobenzenes seems to be identical to that of nitrobenzene.

• Journal of the Korean Chemical Society
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• v.42 no.2
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• pp.214-219
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• 1998

Dynorphin B analogues, $[Arg^{11}, D-Ala^{12}]$dynorphin B, $[D-Ala^2, Ala^6, Arg^{11}, D-Ala^{12}]$dynorphin B, and dynorphin B (1-11) were synthesized by solid-phase method. A chloromethylated polystyrene resin cross-linked with 2% divinylbenzene was substituted with Thr in ethanol to contain 1.20 mmol Thr/g of resin. All amino groups of amino acids were protected with t-Boc group and 2,6-dichlorobenzyl and nitro groups were used to protect the side chains of Tyr and Arg, respectively. Stepwise synthetic method was applied for synthesis of the products. Dicyclohexylcarbodiimide (DCC) and 1-hydroxybenzotriazole (HOBT) were used as the coupling reagents. The crude peptides were purified by gel filteration on Sephadex LH-20 column $(2 \times 50 cm)$ using MeOH/MeCN (3/1) and then characterized with HPLC, amino acid analyzer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.811-813
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• 2003

We investigated the electrical properties of self-assembled (4,4'-Di(ethynylphenyl)-2'-nitro-1-thioacetylbenzene), which has been well known as a conducting molecule having possible application to molecular level negative differential resistance(NDR)[1]. Generally, the phenomenon of NDR can be characterized by the decreasing current with the increasing voltage[2]. To deposit the SAM layer onto gold electrode, we transfer the prefabricated nanopores into a 1mM self-assembly molecules in THF solution. Au(111) substrates were prepared by ion beam sputtering method of gold onto the silicon wafer. As a result, we measured the voltage-current properties and confirmed the negative differential resistance properties of self-assembled organic thin film and measured, using Scanning Tunneling Microscopy(STM).

• Journal of the Korean Chemical Society
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• v.32 no.6
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• pp.513-519
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• 1988

The effect of pressure and temperature on the stabilities of hexamethylbenzene-1,3,5-trinitrobenzene charge transfer complex in carbon tetrachloride has been investigated by spectrophotometric measurements. The absorption spectra of charge transfer complexes were measured at 25, 40, $50^{\circ}C$ under 1, 200, 500, 1000, 1400 bar in this experiments. The equilibrium constants of the complex were increased with pressure and decreased with temperature rising. The absorption coefficients were increased with pressure and temperature. Change of volume, enthalpy, free energy and entropy for the formation of complexes were calculated from the equilibrium constants. The red-shift observed at a higher pressure, the blue-shift at a higher temperature and the relation between pressure and oscillator strength were discussed by means of thermodynamic fuctions.

• Journal of the Korean Chemical Society
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• v.40 no.12
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• pp.741-747
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• 1996

The syntheses and absorption spectra of squarylium and croconium dyes were studied. IR data and negative solvatochromism revealed that squarylium dyes have symmetrical 1,3-bonded squarylium rings. A new class of unsymmetrical squarylium dyes and their precursor have also been synthesized. The λmax of croconium dyes undergoes a bathochromic shift of about 100 nm compared with corresponding squarylium dyes. This shift can he calculated by the Pariser-Parr-Pople molecular orbital method.

• Applied Chemistry for Engineering
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• v.10 no.6
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• pp.857-862
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• 1999

Aminated poly(ether sulfone)(APES) was prepared by amination of nitrated poly(ether sulfone)(NPES) after poly(ether sulfone)(PES) was nitrated with mixed acid of nitric acid and sulfuric acid(sulfuric acid is a catalyst). As a results of the FT-IR spectrum analysis, the nitration of PES was confirmed by the bands of asymmetric stretching and symmetric stretching of $NO_2$ group at 1537 and $1351cm^{-1}$, respectively. Also when the NPES was aminated, it was disappeared to absorbance peaks of $NO_2$ group. And It was confirmed by the bands of asymmetric stretching and symmetric stretching of $NH_2$ group at 3470 and $3374cm^{-1}$, respectively. The optimum condition of the nitration on PES(5 g; 21.55 mmol.) was 12 hr of reaction time, $120^{\circ}C$ of reaction temperature, nitric acid of 28.00 mmol. and sulfuric acid of 52.00 mmol. As a result of the elemental analysis of APES, reapeating unit per amine groups were induced to 0.89. The adsorption rate of NO gas was lower than that of silica gel and active carbon. But the adsorption capacity of NO gas was higher than that of these. When the APES was absorbed to NO gas, the chemical adsorption rate was lower than the physical adsorption rate. But the chemical adsorption capacity of it was higher than physical adsorption capacity.

• Journal of the Korean Chemical Society
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• v.50 no.5
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• pp.362-368
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• 2006

SH group modifying chemicals were used to characterize the eight cysteine residues of cabbage PLD. 5,5-dithiobis(2-nitrobenzoate)(DTNB) was used to titrate the SH group of cysteine residues . Based on the optical density at 412nm due to the reduced DTNB, 4 SH groups are found to be present in a native PLD while 8 SH groups in the denatured PLD whose tertiary structure was perturbed by 8M urea. The results imply that among the 8 cysteine residues of PLD, the half(4) are exposed on the surface whereas the other half are present at the interior of the enzyme tertiary structure. The PLD was inactivated by SH modifying reagents such as p-chloromercuribenzoate(PCMB), iodoacetate, iodoacetamide, and N-ethylmaleimide. At the addition of dithiothreitol(DTT) only the PCMB inhibited PLD activity was recovered reversibly. The micro-environment of the exposed SH group of cysteine residues was examined with various disulfide compounds with different functional groups and we found that anionic or neutral disulfides appear to be more effective than the positively charged cystamine for inactivating the PLD activity. The effect of redox state of cysteine residues on the PLD activity was further explored with H2O2. The oxidation of SH groups by H2O2 inhibited the PLD activity more than 70%, which was mostly recovered by DTT. From these results, we could confirm chemically that all the cysteine residues of PLD are present as in their reduced SH forms and the 4 SH groups exposed on the surface of the enzyme may play important roles in the regulation of PLD activity.