• Elastomers and Composites
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• 제51권3호
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• pp.233-239
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• 2016

Polyethylene (PE) and maleic anhydride-grafted PE (PE-g-MAH) were pyrolyzed, and their pyrolysis products were analyzed using gas chromatography/mass spectrometry (GC/MS) to investigate the influence of MAH grafted onto PE on pyrolysis behaviors. Major pyrolysis products of PE and PE-g-MAH were n-alkanes, 1-alkenes, ${\alpha},{\omega}$-alkadienes, and aromatic compounds. 1-Alkenes were more formed than n-alkanes, ${\alpha},{\omega}$-alkadienes, and aromatic compounds. Butadiene was more produced from PE than PE-g-MAH, whereas toluene and ethyl benzene were more generated from PE-g-MAH than PE. Difference in the pyrolysis behaviors between PE and PE-g-MAH were explained by initial decomposition of MAH moiety.

• Natural Product Sciences
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• 제26권2호
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• pp.132-135
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• 2020

Volatile constituents obtained by water distillation from the aerial parts and root of Onosma dichroanthum Boiss (Boraginaceae) native to the north of Iran were investigated by GC and GC/MS for the first time. Palmitic acid (39.61%) and decane (31.39%) were the major components in the root while decane (26.26%) and phytol (25.52%) were the predominant constituents in the aerial parts. Ketones, aldehydes, alkanes, fatty acids, oxygenated diterpenes and sesquiterpenes were characterized as the most phytochemicals in the aerial parts. Alkanes and fatty acids were identified as the main groups in the root volatile substances. There were two ketone derivatives, belong to apocarotenoids, in the aerial parts; β-ionone and hexahydrofarnesyl acetone.

• Journal of Microbiology and Biotechnology
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• 제3권4호
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• pp.252-255
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• 1993

Pseudomonas maltophilia N246 carrying on OCT plasmid grew on n-alkanes of 6 to 14 carbon atoms, but not on n-alkanes of more carbon atoms. P. maltophilia strains with and without OCT plasmid could utilize primary alcohols. aldehydes and fatty acids derived from n-alkane. The N246 strain could also utilize monocarboxylic and dicarboxylic acids, and terminal branched dimethyloctane. Unlike the genes of alcohol dehydrogenase and aldehyde dehydrogenase which were located on both the chromosome and the OCT plasmid, genes for the alkane hydroxylase components were located only on the OCT plasmid in P. maltophilia N246.

• Bulletin of the Korean Chemical Society
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• 제17권7호
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• pp.625-630
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• 1996

The cobalt-substituted polyoxotungstate [(CoPW11O39)5-] has been used as a catalyst in olefin epoxidation and alkane hydroxylation reactions. The epoxidation of olefins by iodosylbenzene in CH3CN yielded epoxides predominantly with trace amounts of allylic oxidation products. cis-Stilbene was streoselectively oxidized to cis-stilbene oxide with small amounts of trans-stilbene oxide and benzaldehyde formation. The epoxidation of carbamazepine (CBZ) by potassium monopersulfate in aqueous solution gave the corresponding CBZ 10,11-oxide product. Other transition metal-substituted polyoxotungstates (M=Mn2+, Fe2+, Ni2+, and Cu2+) were inactive in the CBZ epoxidation reaction. The cobalt-substituted polyoxotungstate also catalyzed the oxidation of alkanes with m-chloroperbenzoic acid to give the corresponding alcohols and ketones. The presence of CH2Br2 in the hydroxylation of cyclohexane afforded the formation of bromocyclohexane, suggesting the participation of cyclohexyl radical. In the 18O-labeled water experiment, there was no incorporation of 18O into the cyclohexanol product when the hydroxylation of cyclohexane by MCPBA was carried out in the presence of H218O. Some mechanistic aspects are discussed as well.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2019년도 춘계학술논문요약집
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• pp.237-238
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• 2019

• Bulletin of the Korean Chemical Society
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• 제24권8호
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• pp.1207-1210
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• 2003

The effect of solvent structure on the slope in the plot of ln K vs. solute carbon number was examined. It was found that the free energy of methylene group transfer from the gas phase into a solvent was always negative and that the absolute magnitude of interaction free energy between the methylene group and the solvent was always larger than the absolute magnitude of cavity formation free energy of the methylene group in the solvent. Thus, the slope in the plot of ln K vs. solute carbon number was always positive and its value decreases with increase of solvent polarity since the cavity formation energy of the CH₂ unit increases with increase of solvent polarity while the dispersive interaction energy of the CH₂ unit is virtually invariant. We also examined the effect of sequential addition of CH₂ unit to a solvent molecule upon ln K for three homologous series of solvents: n-alkanes, n-alcohols, and n-nitriles. Characteristic trends in the plots of ln K vs. solvent carbon number were observed for individual solvent groups. A decrease of ln K with solvent carbon number was observed for n-alkanes. An abrupt increase in ln K followed by levelling off was observed for n-alcohols while a final slight decrease in ln K after an abrupt increase followed by rapid levelling off was noted for n-nitriles. All of theses phenomena were found related to variation in cavity formation energy. It was clearly shown that a structural change of a polar solvent by sequential addition of CH₂ units causes an abrupt polarity decrease initially, then gradual levelling off, and finally, conversion to a virtually nonpolar solvent if enough CH₂ units are added.

• 한국대기환경학회지
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• 제33권3호
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• pp.265-276
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• 2017

The $PM_{2.5}$ samples were obtained from coal combustion with the four different combustion temperatures (550, 700, 900 and $1100^{\circ}C$) to understand chemical composition in carbonaceous aerosol. OC concentration was the highest when the combustion temperature was $550^{\circ}C$, while, the highest concentration for EC was shown at $700^{\circ}C$ of the coal combustion temperature. However, OC concentrations were very low and EC was not detected when the temperature was over $900^{\circ}C$. It indicates complete combustion was achieved when the combustion temperature was over $900^{\circ}C$. For six groups of organic compounds, n-alkanes and n-alkanoic acids were predominant at all of the combustion temperature in smoke of coal combustion, while, PAHs was only detected at $550^{\circ}C$. The diagnostic ratios of PAHs calculated in this study were 0.59 for Fluoranthene/(Fluoranthene+Pyrene), reflecting the characteristics of coal combustion. The Carbon number Preference Index (CPI) values of n-alkanes which ranged from 0.9 to 1.3 also showed the characteristics of coal combustion.

• 한국의류학회지
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• 제17권4호
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• pp.511-517
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• 1993

Changes of the surface and interface tension with temperature for washing liquids and alkanes were measured by FACE surface tensiometer. Using the extended Fowkes' equation, the dispersion and polar force components of the surface tension were estimated. The results were as follows : 1. The surface tensions of washing liquids and alkanes decreased almost linearly with the increase of temperature. 2. The interface tensions of 0.25% DBS/alkane increased slowly with the increase of temperature. In the case of nonionic surfactant solutions, however, the interface tensions with alkanes varied with the number of hydrophilic ethylene oxide(EO) groups. 3. Of the surface tension of water at $20^{\circ}C$, the dispersion force component was 25.3 dyn/cm and the polar force component was 47.8 dyn/cm. As the temperature increased, both the polar and dispersion force components decreased in a similar fashion. 4. The dispersion force component of surface tension of 0.25% DBS solution was 30.0 dyn/cm, and the polar force component was 2.2 dyn/cm at $20^{\circ}C$. The two components decreased with the increase of temperature. 5. As the temperature increased, the dispersion force component of surface tension decreased and the polar force component increased significantly for 0.25% NPPG-7.5EO solution. In the case of 025% NPPG-10EO, both the dispersion and polar force components decreased slowly, but the polar force component is expected to increase from $60^{\circ}C$. However, the polar force component of surface tension decreased with the increase of temperature for 025% NPPG-15EO solution, and at the temperature higher than $60^{\circ}C$ the surface tension is expected to be composed of only dispersion force component.

• 한국대기환경학회지
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• 제32권2호
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• pp.208-215
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• 2016

Pinic acid (PA) and cis-pinonic acid (CPA) in the atmospheric particulate matter with an aerodynamic diameter of less than or equal to a nominal $10{\mu}m$ ($PM_{10}$) were analyzed for the samples collected during the period of April 2010 to April 2011 at Jongro in Seoul. Both pinic acid and cis-pinonic acid showed higher seasonal average concentrations in summer (PA; $18.9ng/m^3$, CPA; $16.0ng/m^3$) than winter (PA; $5.3ng/m^3$, CPA; $5.9ng/m^3$). They displayed a seasonal pattern associated with temperature reflecting the influence on emissions of ${\alpha}-pinene$ and ${\beta}-pinene$ from conifers and their photochemical reaction. These results were confirmed through Pearson correlation coefficient between CPA, PA and $O_3+NO_2$, temperature. CPA was only correlated with n-alkanes ($C_{29}$, $C_{31}$, $C_{33}$) from biogenic source. PA was correlated with n-alkanes ($C_{29}$, $C_{31}$, $C_{33}$), n-alkanoic acid ($C_{20}$, $C_{22}$, $C_{24}$) from biogenic source and n-alkanes ($C_{28}$, $C_{30}$, $C_{32}$), and n-alkanoic acid ($C_{16}$, $C_{18}$) from anthropogenic source. These results showed that the formation of PA and CPA from ${\alpha}-pinene$ and ${\beta}-pinene$ is related to organic compounds from biogenic source. And it is possible for PA to be effected by organic compounds from anthropogenic source.

• 한국결정학회지
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• 제16권1호
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• pp.43-53
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• 2005

알칸화합물(alkanes)에서 탄소-수소결합을 활성화시켜서 더욱 값이 비싸고 더 유용한 알켄화합물(alkenes)로 만들 수 있는 촉매를 만들고자 지난 수 십 년간 많은 화학자들이 연구해왔다 이러한 목적의 하나로서 두개의 수소를 가지는 이리디움 P-C-P핀서(pincer) 착물 $(IrH_2{C_6H_3-2,6-(CH_2PBu_2^t)_2})$을 성공적으로 합성하였다. 이 착물은 알칸의 탈수소화반응(dehyrogenation)에 아주 효과적인 촉매로 알려졌다 알칸의 탈수소화반응에 촉매독으로 작용하는 질소, 물, 이산화탄소 및 일산화탄소와 같은 작은 화합물들과 직접 반응시켜서 어떻게 촉매독으로 작용하는지를 알아봤다. 촉매독으로 작용할 수 있는 화합물들을 합성하여 핵자기공명분광법(NMR)과 적외선분광법(IR)으로 확인하였고 분자구조를 알아보기 위해서 단결정X-ray 회절법을 통하여 확인하였다. 본 논문에서는 촉매 및 촉매독물질의 합성과 분자구조와 각각의 화합물의 반응성과 특이성을 알아보았다.