• Proceeding of EDISON Challenge
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• 2014.03a
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• pp.371-383
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• 2014

이 연구에서는 팔라듐 착물 $Pd(PPh_3)_2$을 사용한 bromotoluene과 morpholine간의 coupling reaction (Buchwald-Hartwig amination) 반응 메커니즘을 계산화학적 방법을 이용하여 연구하였다. 용매화 자유에너지를 고려한 중간체 에너지를 비교하였으며, 반응물질이 o-bromotoluene 일 때와 p-bromotoluene 일 때, 반응 중간체로 monophosphine 착물이 형성되는 경우와 bisphosphine 착물이 형성되는 경우를 비교하였으며, 반응 중간체로 bisphosphine 착물이 형성되는 경우 cis 이성질체가 중간체인 경우와 trans 이성질체가 중간체인 경우를 비교하였다. 그 결과, 반응물로 p-bromotoluene을 사용할 때 o-bromotoluene을 사용할 때보다 중간체가 상대적으로 더 안정하여 더 좋은 수득률을 얻을 수 있을 것으로 예상되었다. 또한 $Pd(PPh_3)_n(o-tolyl)(N(CH_2CH_2)_2O)$ (n=1 또는 2) 중간체를 제외하고는 모든 경우에서 bisphosphine 중간체가 형성되는 반응경로가 더 안정한 것으로 밝혀졌다. 그리고 $Pd(PPh_3)_2ArBr$의 경우 trans 이성질체가 cis 이성질체보다 안정하지만 $Pd(PPh_3)_2Ar(N(CH_2CH_2)_2O)$의 경우 반대로 cis 이성질체가 trans 이성질체보다 안정한 것으로 나타났다.

• Analytical Science and Technology
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• v.15 no.6
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• pp.529-533
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• 2002

The separation and determination method of racemic isomers of flurbiprofen in urine samples have been investigated using column switching- HPLC, which include the sample treatment and concentration column. The optical rotation of two isomers separated were measured to identify d-form and l-form. The calibration curves are liear in the ranges of $0.11-5.4{\mu}g/mL$ for both d-form and l-form. The detection limits were $0.031{\mu}g/mL$ for l-isomes and $0.027{\mu}g/mL$ for d-isomer. The coefficients of variation of intra-day and inter-day precision of this method were about 1.8%. The present method was apllied to determine the concentration of racemic isomers in urine sample from human eating the drug.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.11b
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• pp.381-383
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• 2003

유기염소계농약류 25종을 분석한 결과 HCHs(4종, endosulfan(2종), octachlorostyrene은 모든 시료에서 검출되지 않았으며 trans-nonachlor, heptachlor는 각각 한 지점의 붕어에서 검출되었고 나머지는 검출되지 않았다. Chlordane의 경우 두 이성질체가 한 지점의 붕어에서 검출되었고, DDT는 6개 이성질체 중 p,p’-DDT와 p,p’-DDD가 한 지점의 붕어에서 검출되었으며 o,p’-DDT는 한 지점의 황소개구리에서 검출되었다. 그 외의 이성질체는 모든 시료에서 검출되지 않았다.

• Journal of the Korean Chemical Society
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• v.45 no.6
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• pp.538-545
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• 2001

The ratio of regioisomers in nitration of biphenyl derivatives containing electron-with-drawing group was examined. The ratio of isomers was determined efficiently by quantitative analysis of $^1$H NMR spectrum of product mixture based on $^1$H NMR spectrum of each isomer. Some isomers were isolated after chemical transformation, nitro to amine or carboxylic acid to its ethyl ester, because direct separation was very difficult. To improve the regiselectivity, representative several reaction conditions were tried and the NMR method was applied to determine regioselectivity in nitration of biphenyl derivatives. It was observed that the regioselectivity depend on not only reaction conditions but also position and kind of substituents.

• Microbiology and Biotechnology Letters
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• v.29 no.2
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• pp.122-126
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• 2001

Eleven bacterial strains which were able to utilize terephthalic acid as a carbon and an energy source for growth were isolated from the soil of 7 water quality evaluation points in Kyonggi area of Korea. According to the report from the authorities, biochemical oxygen demands of the water at 4 points were reported over 20 ppm but those of 3 points were repOlted less than 2 ppm in 1997. Optimum temperatures of growth and terephthalic acid degrading activity of some isolates were not identical but optimum growth temperature was 30$^{\circ}$C. Most of the isolates utilized one or two of the phthalate isomers as a carbon source for growth and the isolates from the 4 contaminated points showed higher terephthalic acid degrading activity than those from the 3 clean points.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10a
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• pp.563-567
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• 2006

현재 IT분야의 끊임없는 발전과 더불어 BT/NT 분야와의 협업이 활발히 진행되고 있는 가운데, 광학 이성질체에 대한 연구는 그 중요성이 점점 증가되고 있다. 광학 이성질체는 생체 내에서 작용할 경우 성질, 기능, 효과에서 정반대 결과를 일으키기에 제약 산업 등 응용분야에서는 사용을 위해 효과적으로 식별하여 분리할 필요성이 존재한다. 이런 실험은 단계가 복잡하고 결과를 분석하고 시각화하기 어렵다. 이를 해결하기 위해 본 논문에서는 광학 이성질체의 분리연구를 위한 그리드 기반의 Chiral-MGrid 시스템을 제공한다. Chiral-MGrid 시스템은 분리연구 관련 실험을 그리드 기반에서 one set operation으로 수행할 수 있는 서비스를 제공한다.

• Journal of the Korean Chemical Society
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• v.36 no.6
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• pp.849-856
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• 1992

We prepared a simple, economic and versatile preparative system for an enantiomeric separation. Hydrophobic amino acid enantiomers were resolved in the preparative scale by a centrifugal liquid chromatography on the N-hexadecyl-L-proline coated reversed phase. The factors controlling the retention and resolution of racemic amino acids such as the concentration of Cu(Ⅱ), pH of the eluent, the type and content of organic modifier, and rpm of CLC were examined. Several mg of hydrophobic amino acid enantiomers were separated preparatively. To separate all of different amino acid enantiomers, various coating material will be investigated.

• Journal of the Korean Chemical Society
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• v.56 no.2
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• pp.188-194
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• 2012

The interaction of 4-alkylbenzoic acid isomers with the micellar system of TTAB (tetradecyltrimethylammonium bromide) was studied by the UV/Vis spectrophotometric method. The solubilization constants ($K_s$) of 4-alkylbenzoic acid isomers into the TTAB micellar system and the critical micelle concentration (CMC) of TTAB have been measured with the change of temperature. Various thermodynamic parameters have been calculated and analyzed from those measurements. The results show that the values of ${\Delta}G^o{_s}$ for the solubilization of all the isomers are negative and the values of ${\Delta}H^o{_s}$ and ${\Delta}S^o{_s}$ are all positive within the measured temperature range. The effects of additives (n-butanol and NaCl) on the solubilization of 4-alkylbenzoic acid isomers have been also measured. There was a great change on the values of $K_s$ and CMC simultaneously with these additives. From these changes we can postulate that the solubilization sites of 4-alkylbenzoic acids are the core or deep palisade region of the TTAB micelle.

• Applied Chemistry for Engineering
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• v.21 no.3
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• pp.337-342
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• 2010

The interaction of monochlorophenol isomers with the micellar system of TTAB (tetradecyltrimethylammonium bromide) was studied by the UV/Vis spectrophotometric method. The solubilization constants ($K_s$) of monochlorophenol isomers into this micellar system have been measured with the change of temperature. Various thermodynamic parameters (${\Delta}G^{\circ}_s$, ${\Delta}H^{\circ}_s$, and ${\Delta}S^{\circ}_s$) have been calculated and analyzed from the dependence of $K_s$ values on the temperature. The results show that the values of ${\Delta}G^{\circ}_s$ and ${\Delta}H^{\circ}_s$ are all negative but the values of ${\Delta}S^{\circ}_s$ are all positive for the solubilizations of all isomers within the measured temperature range. The effects of additives (n-butanol and NaCl) on the solubilization of monochlorophenol isomers by the same surfactant system have been also measured. There was a great change on the values of $K_s$ and CMC simultaneously with these additives. From these changes we can postulate the solubilization sites of each isomer in the micellar system of TTAB.

• Journal of the Korean Chemical Society
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• v.54 no.4
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• pp.374-379
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• 2010

The interaction of dichlorophenol isomers with the micellar system of TTAB (tetradecyltrimethylammonium bromide) was studied by the UV/Vis spectrophotometric method. The solubilization constants ($K_s$) of dichlorophenol isomers into the micellar system have been measured with the change of temperature and the various thermodynamic parameters have been calculated and analyzed from these changes. The results show that the values of ${\Delta}G^{\circ}_s$ and ${\Delta}H^{\circ}_s$ are all negative within the measured temperature range. The effects of additives (n-butanol and NaCl) on the solubilization of dichlorophenol isomers have been also measured. There was a great change on the values of $K_s$ and CMC simultaneously with these additives. From these changes we can postulate the solubilization sites of each isomers in the micellar system of TTAB.