• Korean Chemical Engineering Research
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• v.40 no.6
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• pp.669-675
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• 2002

The alkenylation of o-xylene with 1,3-butadiene to make OTP(ortho-tolyl Pentene) was carried out over liquid phase NaK alloy, Na metal and the metallic sodium dispersed on the specific support such as NaX and $Al_2O_3$. Liquid phase NaK alloy showed the improved conversion and selectivity when they were pretreated by ultrasound to increase the dispersion. For the case of metallic sodium, the induction period for the formation of homogeneous metal sodium solution with high dispersion was needed before the reaction. In the case of metallic sodium dispersed on support, more than 80 % conversion could be obtained without induction period regardless of supports used. But 85 % of the metallic sodium was resolved into the reaction mixture after reaction for 7 hours. The amount of byproducts, oligomers, produced from OTP and 1,3-butadiene increased with the amount of 1,3-butadiene introduced and the selectivity to OTP was in inversely proportional to the conversion.

• Molecular & Cellular Toxicology
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• v.2 no.4
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• pp.229-235
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• 2006

Volatile organic compounds (VOCs) are a major component of urban air pollution. It is documented that low exposure levels of VOCs induce alterations in immune reactivity resulting in a subsequent higher risk for the development of allergic reactivity and asthma. Despite these facts, there are few reports on the affected primary target and the underlying effective causal mechanisms. So in this study, to better understand the risk of BTX (benzene, toluene and o-xylene) which are the major VOCs and to identify novel biomarkers on immune response to these VOCs exposure in human T lymphocytes, we performed the toxicogenomic study by analyzing of gene expression profiles using 35 k human oligo-microarray. BTX generated specific gene expression patterns in Jurkat cell line. By clustering analysis, we identified some genes as potential markers on immuno-modulating effects of BTX. Four genes of these, HLA-DOA, ITGB2, HMGA2 and 5TAT4 were the most significantly affected by BTX exposure. Thus, this study suggests that these differentially expressed immune genes may play an important role in the pathogenesis on BTX exposure and have significant potential as novel biomarkers of exposure, susceptibility and response to BTC.

• Korean Journal of Chemical Engineering
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• v.35 no.11
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• pp.2172-2184
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• 2018

The production of isophthalic acid (IPA) from the oxidation of m-xylene (MX) by air is catalyzed by $H_3PW_{12}O_{40}$ (HPW) loaded on carbon and cobalt. We used $H_2O_2$ solution to oxidize the carbon to improve the catalytic activity of HPW@C catalyst. Experiments reveal that the best carbon sample is obtained by calcining the carbon at $700^{\circ}C$ for 4 h after being impregnated in the 3.75% $H_2O_2$ solution at $40^{\circ}C$ for 7 h. The surface characterization displays that the $H_2O_2$ modification leads to an increase in the acidic groups and a reduction in the basic groups on the carbon surface. The catalytic capability of the HPW@C catalyst depends on its surface chemical characteristics and physical property. The acidic groups play a more important part than the physical property. The MX conversion after 180 min reaction acquired by the HPW@C catalysts prepared from the activated carbon modified in the best condition is 3.81% over that obtained by the HPW@C catalysts prepared from the original carbon. The IPA produced by the former is 46.2% over that produced by the latter.

• Journal of the Korean Society of Safety
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• v.21 no.3 s.75
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• pp.45-52
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• 2006

The AITs(autoignition temperatures) describe the minimum temperature to which a substance must be heated, without the application of a flame or spark, which will cause that substance to ignite. The AITs are often used as a factor in determining the upper temperature limit for processing operations and conditions for handling, storage and transportation, and in determining potential fire hazard from accidental contact with hot surfaces. The measurement AITs are dependent upon many factors, namely initial temperature, pressure, volume, fuel/air stoichiometry, catalyst material, concentration of vapor, time lag. Therefore, the AITs reported by different ignition conditions are sometimes significantly different. This study measured the AITs of benzene, toluene and xylene isomers from time lag using AS1M E659-78 apparatus. The experimental ignition delay times were a good agreement with the calculated ignition delay times by the proposed equations wtih a few A.A.D.(average absolute deviation). Also The experimental AITs of benzene, toluene, o-xylene, m-xylene and p-xylene were $583^{\circ}C,\;547^{\circ}C,\;480^{\circ}C,\;587^{\circ}C,\;and\;557^{\circ}C$, respectively.

• Journal of Environmental Health Sciences
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• v.24 no.2
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• pp.74-79
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• 1998

This study was conducted to evaluate the surfactant solutions which influence solvent extraction from light hydrocarbon contaminated soils. Nine characteristic compounds were studied: benzene, toluene, ethylbenzene, o-xylene, mxylene, p-xylene, n-propylbenzene, 1,2,4-trimethylbenzene, and n-butylbenzene which were found in gasoline. Adsee-799 and Witbreak DRA-22 showed some extractive capacity for light hydrocarbons from soil. There was no added advantage obtained by using other surfactants in this study. No removal of contaminants from soil was observed when the surfactant concentration was 0.5 percent or below. When the surfactant concentration was 4 percent, the average recovery for some hydrocarbons was 10.8 percent, which was the best obtained at these levels. There was 10 percent surfactant contribution for methanol extraction from soil with the Witbreak DPG-482 and Witbreak DRA-22. This study provided a useful screening technique for procedures that can be used to remediate soils contaminated with light hydrocarbons.

• Journal of Environmental Science International
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• v.14 no.6
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• pp.543-553
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• 2005

In recent days, photochemical smog due to the rapid industry development and vehicle increasement has become a critical pollutant in the metropolitan area and the number of ozone alarm signal has increased every year. This research was performed to evaluate VOCs emission source characteristics and concentration of VOCs in Daegu. The site average concentration was observed in the following order: industrial area > commercial area > residential area. Most of the VOCs species except toluene showed variations with higher concentration during nighttime, and lower concentration during the daytime. The major VOCs of stationary emission source were BTEX(benzene, toluene, ethylbenzene. xylene) and methylene chloride, trichloroethene and styrene. Also, those of automobile exhaust were toluene and benzene. Also, the major VOCs concentration emited by the vehicle fuel was observed in the following order: gasoline > light oil > liquefied petroleum gas (L.P.G). Correlation coefficients values were estimated between major VOCs such as toluene, ethylbenzene, m,p-xylene, o-xylene. Results showed that correlation coefficient values were significant magnitude above 0.76. Also, there showed highly significant correlations among ethyl benzene, m,p-xylene, and o-xylene concentration(Pearson correlation coefficients, r=0.868-0.982). Calculated correlation coefficients among commercial area,industrial area and residential area were 0.934-0.981, they showed high correlation. There showed highly correlation between stationary emission source and industrial area, compared with commercial area and residential area. Also, calculated correlation coefficients among commercial area, industrial area, residential area and automobile exhaust were 0.732, 0.725, 0.777, respectively.

• Journal of the Microelectronics and Packaging Society
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• v.2 no.1
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• pp.35-48
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• 1995

마이크로회로내에서 티탄산바륨 중 바륨의 일부가 납으로 치환됨에 따른 전기적 특 성의 변화를 확인하기 위하여 MOD(금속유기화합물 분해법)공정에 의 barum 2-ethylhexanoate, barium neodecanoate, lead 2-ethylhexanoate 및 titanium dimethoxy 야 -2-ethylhexanoate 와 같은 MOC(금속 유기화합물) 들을 합성하고 공통 용매에 대한 용해 도를 시험하였다. 그 결과 barium 2-ethylhexanoate 만 p-xylene에 대한 용해도가 낮았으며 그 외의 다른 MOC들은 모두 p-xylene 단일 용매에 매우 잘 용해되었다. 바륨의 일부가 납 으로 치환된 티탄산 납바륨 박막은 MOC 혼합용액을 ITO/glass, Pt/SiO2/Si 및 Pt/Ti/SiO2/Si 웨이퍼 기판 위에 spin coating 하고 소성하여 얻었다. 이와 같이 얻어진 박막 의 전기적 특성을 측정하고 그 결과를 비교 고찰하였다.

• Journal of Magnetics
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• v.16 no.2
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• pp.186-191
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• 2011

[ $YBa_2C_3O_{7-x}$ ]films were fabricated on a $SrTiO_3$ (100) substrate using a trimethylaceate propionic acid (TMAP)-based MOD process by controlling the precursor solution viscosity, firing temperature, and by using various coatings. The viscosity of the precursor solution was controlled by the addition of Xylenes. The films were heat treated with different temperatures from 750 to $800^{\circ}C$. c-axis oriented films were obtained. After adding 9 ml of Xylene into the precursor solution, the $T_c$ of the YBCO film, which was coated 2 times and heat treated at $800^{\circ}C$, was 86 K and the measured $J_c$ was above 2.5 MA/$cm^2$ at 77 K in a zero-field.

• Analytical Science and Technology
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• v.9 no.4
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• pp.392-398
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• 1996

Eleven organic chemical substances, tetrachloroethylene, ethyl benzene, p-xylene, o-xylene, isopropyl benzene, n-propyl benzene. 1,2,4-trimethyl benzene, 1,3,5-trimethyl benzene, p-isopropyl toluene. see-butyl benzene, and naphthalene, which have hazardously influenced to human, were extracted from untreated wastewater collected at 26 companies of 8 types industry in the basin of Kwangju stream. Their structures were elucidated by Gas Chromatography/Mass Spectrometry(GC/MS) and in comparison with each standard reagents.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2016.10a
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• pp.120-120
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• 2016