• Elastomers and Composites
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• 제49권1호
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• pp.31-36
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• 2014

Sebacic acid, isophthalic acid, ethylene glycol, neopentyl glycol를 각각 1몰씩 사용하여 폴리에스터 폴리올을 합성하였다. 합성된 폴리올의 수산기가는 56.6 mg KOH/g이고 분자량은 1,980 g/mole 이었다. 합성한 폴리에스터 폴리올에 toluene diisocyanate와 쇄연장제로 ethylene glycol, 1,4-butandiol, 1,2-propylene glycol을 각각 넣고 폴리우레탄을 합성하였다. GPC로 측정한 3 가지 폴리우레탄의 분자량은 각각 5850, 6160, 6480 g/mole 이었다. FT-IR에 의한 구조분석에서 폴리에스터 폴리올은 3600 $cm^{-1}$ 부근에서 -OH 기가 관찰되었고, 2950 $cm^{-1}$ 에서 sebacic acid의 -CH shoulder가 나타났으며, ester의 carbonyl group은 1730 $cm^{-1}$ 부근에서 나타났고, isophthalic acid의 benzene ring은 1600 $cm^{-1}$, 740 $cm^{-1}$에 관찰되었다. 폴리우레탄의 -OH 피크가 3600 $cm^{-1}$ 에서 나타났고, 3300 $cm^{-1}$ 부근과 1530 $cm^{-1}$ 에서 우레탄기 중의 -NH 기를 확인할 수 있었다. $^1H$ NMR에 의한 구조분석에서 폴리에스터 폴리올은 sebacic acid는 1.3, 1.5, 2.1 ppm에서, isophthalic acid는 7.3, 8.1, 8.7 ppm에서, ethylene glycol은 4.2 ppm에서, neopentyl glycol은 0.8, 3.2, 3.9 ppm에서 관찰되었다. 폴리우레탄의 경우에는 폴리에스터 폴리올과 유사하나 toluene diisocyanate의 도입에 의한 벤젠고리의 피크가 7 ppm에서 미약하게 나타났다.

• 한국환경농학회지
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• 제12권2호
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• pp.144-152
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• 1993

오염된 하천수, 토양 및 폐기물 침출수등의 미생물 분리원으로 부터 합성세제(ABS)를 유일 탄소원으로 이용할 수 있는 미생물들을 분리하여, 이중 합성세제(ABS) 분해능이 가장 우수한 한 종의 균을 분리하여 동정한 결과 P. fluorescens 또는 그 유연균으로 밝혀졌으며, 최적 생장온도는 $30^{\circ}C$였고 최적 생장 pH는 pH 7.0이었다. 분리균주의 탄화수소 자화능 및 중금속에 대한 내성을 조사한 결과 benzene, cyclohexane, xylene 및 catechol은 탄소원으로 이용할 수 있는 반면 phenol, toluene, salicylate, naphthalene은 탄소원으로 이용하지 못하였으며, 중금속중 zinc chloride, lead nitrate, copper sulfate에 대하여는 강한 내성을 나타내었으나 mercury chloride, silver nitrate에 대하여는 내성이 약했다. 분리균의 합성세제(ABS) 분해율을 조사한 결과 ABS 20${\mu}g$/ml의 농도에서 4일후 약 55%, 100${\mu}g$/ml 농도에서는 약 60% 각각 분해되었다. 합성세제 (ABS) 분해에 따른 benzene ring의 분해율을 조사한 결과 시간이 경과 할수록 합성세제(ABS) 분해에 비례하여 benzene ring도 분해되었다. ABS 농도 20${\mu}g$/ml 및 100${\mu}g$/ml에서 benzene ring은 각각 38% 및 45% 분해되었다. COD의 분해와 ABS 분해를 비교검토한 결과 COD는 배양 24시간까지 급격하게 분해 되었으나 그 이후부터 서서히 계속해서 분해되었으며 ABS는 처음부터 서서히 계속적으로 분해되었다. ABS를 첨가하지 않고 배양한 균과 ABS를 1,000${\mu}g$/ml 농도가 되게 첨가하여 배양한 균과의 균체내 아미노산조성을 비교한 결과 아미노산총량은 각각 104.9mg/g 및 115.0mg/g으로서 ABS를 첨가하여 배양한 분리균에서 9.4% 증가 되었으며, 균체내에 Glx(Glu + Gln) 및 proline이 각각 11.1%, 9.2%로 비교적 많이 함유하고 있었고, 특히 cysteine은 ABS를 첨가하지 않고 배양한 분리균에 비해 ABS를 첨가하여 배양한 균에서 약 2.4배 높게 나타났다. ABS를 첨가하지 않고 배양한 분리균은 산성 아미노산인 Asx(Asp + Asn)와 Glx(Glu + Gln)가 비교적 많이 생성된 반면, ABS를 첨가하여 배양한 분리균에서는 염기성 아미노산인 histidine, lysine 및 argnine이 비교적 많이 생성되었다.

• 약학회지
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• 제41권3호
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• pp.298-304
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• 1997

Molecular mechanics and conformation search methods were carried oyt to investigate the relationship between conformations and thromboxane synthetase ingibitory activities of om ega-pyridylalkenoic acids. The initial geometries of ${\omega}$-pyridylalkenoic acids and heme part of cytochrome P-450 were obtained from MM+ geometry optimization. The bond lenths and angles were not varied by step during the conformation searching. Stable conformers of some ${\omega}$-pyridylalkenoic acids were obtained by comformational search method. The distances were 8.5~10.8 ${\AA}$- between N atom at 3-position of pyridine ring and C atom at carboxylic group of stable ${\omega}$-pyridylalkenoic acids. The conformations of ${\omega}$-pyridylalkenoic acids and heme part complex were determined by same method. In theses structures, benzene ring and ethylene group in ${\omega}$-pyridylalkenoic acids are making the structure more rigid and increase inhbitory activity. The electron donating groups in C atom shich is connected to pyridine ring also increase activity.

• Bulletin of the Korean Chemical Society
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• 제20권8호
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• pp.905-909
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• 1999

Reaction of tetrahomodioxa p-phenylcalix[4]arene with ethyl bromoacetate and potassium carbonate in ace-tone leads to the title tetra ester derivative, 7,13,21,27-tetra-phenyl-29,30,31,32 -tetrakis(ethoxycarbonyl)meth-oxy-2,3,16,17-tetrahomo-3,17-dioxacalix[4]arene, its structure was determined by NMR spectra as 1,4-alternate conformation. The molecular structure has been solved by X-ray diffraction methods. The molecule has a conformation with pseudo center of symmetry. The benzene ring A is up, ring C is down, B and D rings are flat with respect to the plane of the macrocyclic ring.

• Bulletin of the Korean Chemical Society
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• 제18권10호
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• pp.1076-1082
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• 1997

The infrared, Raman, and jet-cooled laser-induced fluorescence excitation spectra of 1,2,3,4-tetrahydronaphthalene have been recorded and analyzed. The observed vibrations have been assigned to understand the conformational behaviors in its electronic ground (S0) and excited (S1) states. Ab initio at the HF/6-31G** level and molecular mechanics (MM3) force field calculations have been carried out to generate the complete normal mode frequencies of the molecule in its S0 state. The vibrational frequencies calculated from the ab initio method show a better agreement with the observed infrared and Raman frequencies than those calculated from the MM3 method. In several cases, the normal mode calculations were very helpful to clarify some ambiguities of previous assignments. In addition, the ring inversion process between two twisted conformers of 1,2,3,4-tetrahydronaphthalene has been reexamined utilizing ab initio calculation. The results show that the ring inversion energy is in the range of 3.7-4.3 kcal/mol which is higher than the previously reported AM1 value of 2.1 kcal/mol.

• Bulletin of the Korean Chemical Society
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• 제20권10호
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• pp.1195-1199
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• 1999

2-(2,4,5-Trimethoxyphenyl)-4-methylene-1,3-dioxolane (1b), 2-(2,4,6-trimethoxyphenyl)-4-methylene-1,3-di-oxolane (2b), and 2-(3,4,5-trimethoxyphenyl)-4-methylene-1,3-dioxolane (3b) were prepared and polymerized with boron trifluoride. Boron trifluoride catalyzed reaction proceeded via mainly ring-opening polymerization and cyclization reaction to yield poly(keto ether) and 3(2H)-dihydrofuranone. The yields of polymer and cyclized product exhibited a dependency on the position of the methoxy substituents in the benzene ring of 2-phenyl-4-methylene-1,3-dioxolane derivatives. Electrophilic attack of methylene or oxygen atom on 4-meth-ylene-1,3-dioxolane ring were suggested for the polymerization and cyclization.

• 대한화학회지
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• 제15권6호
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• pp.370-377
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• 1971

The Carbon-14 content in surface air at Seoul, Korea, was measured from February 1970 to August 1971 and a Larix Leptolepis, Gordon tree (Ip-Gal Namu) grown at Kwang-Nung, Kyunggi-Do, Korea, having 37 growth rings, was assayde for $^{14}C$. From the results of the surface air study, it was calculated that during the above period the inventory of excess $^{14}C$ in the atmosphere decreased with a half-time of 4.6 years. The overall yearly decrease was also checked. The tree-ring study showed that the tree's atmosphere was affected by $^{14}C$ from nuclear tests after 1956. In one study, atmospheric $CO^2$ samples were collected bi-monthly by the absorption of $CO^2$ in alkaline hydroxide solution. In the other, 5 year annual growth rings were assayed for radiocarbon. For the radioactivity measurement, carbon atoms in samples were converted to carbon atoms of benzene. The resulting benzene was taken as primary solvent for liquid scintillation counting.

• 대한화학회지
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• 제21권4호
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• pp.235-245
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• 1977

교감신경 흥분성 amine류의 분자구조와 약리효과 간의 관계를 설명하기 위하여 phenethylamine에서 benzene 고리와 ethylamine의 ${\alpha},{\beta}$ 위치와 amine의 질소에 hydroxy기와 methyl기 등을 도입한 23종의 약품에 대한 분자 특성을 EHT법으로 계산하여 검토하였다.

• Bulletin of the Korean Chemical Society
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• 제25권12호
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• pp.1840-1844
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• 2004

The mass spectra of benzophenones, 2-benzoylthiophenes, 2-benzoylpyrroles, and 2-benzoylfurans which have substituents at the m- and p-positions of the benzoyl ring were analyzed to find correlations against the Hammett substituent parameter ${\sigma}\;and\;{\sigma}^+$. The slopes of the plots of the intensities of the fragments from the heterocycles against those of the benzene gave sets of meaningful values for the indices of aromaticity of the heterocycles: benzene 1.00; thiophene 0.94, pyrrole 0.82, and furan 0.74.

• 대한화학회지
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• 제18권4호
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• pp.239-243
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• 1974

합성한 MB BA0와 EBBA의 NMR spectrum 의 분석결과로 N-(p-methoxy benzylidene)-p-n-butylaniline(MBBA)dhk N-(p-ethoxy benzylidene)-p-n-butylaniline(EBBA)분자내의 p-n-butylaniline의 벤젠핵과 분자내의 다른 이중결합 사이에 conjugation이 일어나고 있지 않음을 발견하였으며 이 벤젠핵은 분자 방면으로부터 이탈되어 있다는 결론과 분자궤도 계산겨로가 벤젠기가 평면에서 30도 이탈되어 있을 때 minimum energy conformation을 지님을 알았고 이는 NMR 분석결과와 잘 일치하였다.