• Journal of the Korean Chemical Society
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• v.37 no.2
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• pp.220-227
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• 1993

Silaethene $Cl_2$Si=$CHCH_2^tBu$, generated as a metastable reaction intermediate by the thermal eliminatio of LiCl from lithiated compound $Cl_2$Si=$CHCH_2^tBu$, react with propene, 2-methylpropene, 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, and anthracene to give ene-reaction product, 2+2-, and 2+4-cycloadducts. They are isolated by vacuum fractional distillation method and spectroscopically identified.

• Journal of the Korean Chemical Society
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• v.53 no.3
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• pp.302-307
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• 2009

Investigation was conducted to examine whether photochemical reaction of N-(tributylstannyl)- methylphthalimide generates an azomethine ylide intermediate in its excited state as its silyl derivative N-(trimethylsilyl)methylphthalimide which has been observed to form an azomethine ylide. The irradiation of N-(tributylstannyl)methylphthalimide in $D_2O-CH_3$CN generates mono-deuterated N-methylphthalimide as an exclusive product which supports the efficient generation of azomethine ylide intermediate and its trapping by water molecule through a proto-destannylation pathway. However the generated tributylstannyl subsitiuted ylide was not observed to be trapped with a dipolarophile such as methyl acrylate and acrylonitrile present in the reactions which is in contrast with the ylide from N-(trimethylsilyl)methylphthalimide.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.10
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• pp.969-982
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• 2016

Recently, the researches to discovery drug candidates from natural herbs have received considerable attention. In human body, enzyme mostly metabolize the compounds of natural herbs. In this study, we analysis the enzyme interactions using assoication mining. We get this data from BRENDA(: BRaunschweig ENzyme DAtabase) system. Based on enzyme interaction model, we divide the metabolites into substrate metabolites, product metabolites, inhibitor metabolites, and activating metabolites. We then compose substrate metabolite transaction, product metabolite transaction with each metabolites and enzyme interaction transaction with all metabolites. Also we take account of organism for each transactions. We mine frequent metabolites and patterns from six transactions using association rule mining. And we analysis the relationship among metabolites. As a result, we identify the distributions and patterns of metabolites consist in enzyme interactions. We found that metabolites include in only substrate are identified and have very low supports. This results can be useful to develop the effective metabolism prediction model for compounds of natural herbs.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.07a
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• pp.388-393
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• 2002

최근 국민 식생활이 서구화로 변화하면서 식용유의 수요량도 급격히 증대되었다. 식용유는 장기간 고온에서 사용하기 때문에 여러 종류의 화학반응이 발생하여 각종 휘발성 산화 생성물 및 비휘발성 산화 생성물이 생성된다 (Kim et al., 1999). 휘발성 산화 생성물은 고유의 휘발성 향(odor)성분을 발생시키는데 이것은 식품의 변질 유무 및 식품의 품질 평가에 기준으로 중요하게 이용된다. (Noh et al., 2000). 현재까지 식용유는 생산과정에서는 품질관리가 엄격하게 되어 왔지만 유통과정과 소비과정에서의 품질 관리와 풀질 검사 면에서는 미흡했던 것이 사실이다. (중략)

• Journal of the Korean Chemical Society
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• v.34 no.3
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• pp.239-247
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• 1990

The gas-phase S_N2$ reactions can be classified into neutral bimolecular, solvated, and ionic reactions; the neutral bimolecular reaction proceeds via retention mechanism whereas the ionic reaction produces inversion products. In the reaction of solvated nucleophile with one solvent molecule, a six-center transition state (TS) is formed and the two processes i.e., retention and inversion, are found to compete with a favored path depending on the electronic effect of the nucleophile and substituents in the substrate and on the steric requirement. In the ionic reaction, the difference in the energy barrier between the two processes reduces to a small value when the substrate methyl group is made bulky, leaving ability of the leaving group is improved and at the same time the negative charge of the nucleophile is dispersed. When the reaction center atom in the $S_N2$ reaction is changed to a larger sized second row elements, the activation barrier decreases since the steric crowding in the penta-coordinated TS is relieved. However within the same row, the barrier was found to increase as the atomic size decreased. For the boron, B, the barrier height was the least since in addition to the relatively large atomic size compared to C and N, it forms tetra-coordinated TS so that the steric crowding becomes nearly negligible.

• Proceeding of EDISON Challenge
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• 2017.03a
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• pp.172-174
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• 2017

메탄올 용매 내에서 1,2-dichloroethane ($C_2H_4Cl_2$)의 photo-induced halogen elimination 과정을 계산화학적 방법으로 분석하였다. 특히 실험적 방법으로 분석이 까다로운 중간체 및 반응 메커니즘 분석에 집중하였다. DFT(${\omega}B97XD$ / aug-cc-pVTZ) 계산을 기반으로 진행하였으며, 추가적인 분석을 위해 중간체 샘플링 프로그램이 사용되었다. 그 결과 $C_2H_4Cl_2$ 반응계와 유사하게 bridged 형태의 중간체가 생성되는 것을 확인하였다. 또한 반응물, 생성물, 중간체 2개 및 transition states 2개로 구성된 반응 메커니즘을 밝혀내었다.

• Polymer(Korea)
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• v.32 no.2
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• pp.157-162
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• 2008

To investigate the characteristics of pyrolysis for LDPE, LLDPE and HDPE, the low temperature pyrolysis was carried out in the range of 425 to $500^{\circ}C$ for 35 to 65 min. The liquid products formed during pyrolysis were classified into gasoline, kerosene, light oil and wax according to the distillation temperatures based on the petroleum product quality standard of Korea Petroleum Quality Inspection Institute. TGA experiments for three PE samples showed that the onset temperature of pyrolysis increased with increasing heating rate, and the onset temperature of pyrolysis at a fixed heating rate was in the order of LDPE$475^{\circ}C$. Yields of gasoline and kerosene were highest at $450^{\circ}C$, 65 min and decreased slightly at above $475^{\circ}C$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.1
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• pp.21-25
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• 2002

The contribution of lipid to thermal flayer generation from glucose-protein reaction was accomplished by isolating flavor compounds from casein-glucose (CG)and casein-glucose-coin oil (CGL) which were stored for 2 and 4 weeks at 6$0^{\circ}C$ and then reacted at 16$0^{\circ}C$ for 1hr. The volatiles from the reactant mixtures were isolated by a solvent extraction method with methylene chloride and analyzed by gas chromatography and gas chromatography-mass spectrometry. Pyrazine, methylpyrazine, 2,5-dimethylpyrazine, 2-dimethylpyrazine ,2-ethy-5- methyIpyrazine and 2-acetylpyrrole originated from interaction of thermal degradation of casein and lipid oxidation were identified in the CGL samples. It was also found that 3-methyl-1-butanol, 2-cyclopene-1,4-diode, heptanal, nonanal, and 2-heptanone were derived from lipid source. Two additional fatty acids, heptanoic acid and octanoic acid were also identified in the CGL samples. 5-Hydroxymethyl-2-furfural, the most abundant volatile, was responsible for the formation of sugar degradation product. The results suggested that the presence of lipid in the samples had more effect on the contribution of volatile formation of glucose-protein thermal reaction than the absence of lipid in the samples.

• Journal of the Korean Chemical Society
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• v.26 no.3
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• pp.172-178
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• 1982

A psoralen-DNA monoadduct analogue, 4',5'-dihydropsoralen (DHP) is synthesized and its photophysical properties such as fluorescence quantum yield (0.08), phosphorescence quantum yield (0.013), fluorescence lifetime (0.95ns), and phosphorescence lifetime(0.039s) were measured in ether solution and in frozen matrix state at 77K. The photocycloaddition reaction of DHP with tetramethylethylene(TME) was carried out in solution and in the frozen state. The major photoadduct was isolated and characterized by elemental analysis and physical methods such as UV, IR, NMR, and mass spectrometry. The major DHP-TME photoadduct was proved to be an 1 : 1 $C_4$-cycloadduct formed through 2 + 2 cycloaddition of the pyrone double bond of DHP to TME.

• Proceedings of the Membrane Society of Korea Conference
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• 1992.10a
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• pp.43-44
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• 1992

촉매막반응기란 반응기와 분리막이 동시에 하나의 과정으로 결합된 unit로, 촉매막반응기를 사용할 경우 가역 반응에서 막을 통한 생성물의 선택적 제거는 화학 평형이동을 유발시켜 열역학적으로 얻을수 있는 평형 전환율보다 높은 전환유을 얻을 수 있다. 본 연구는 이러한 촉매막반응기의 성능에 대한 실험적 연구로, 산 촉매하에서 일어나는 MTBE 분해반응을 12-텅스토인산 촉매상에서 수행하였다.