• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.05a
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• pp.267-268
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• 2001

Chlorobenzenes (CBs) are ubiquitous hydrophobic chlorinated organic compounds in the environment. These compounds are used as de-ordants, solvents and pesticides, as well as byproducts of agro- or petro-chemical related manufacturing processes, such as PCBs and pentachlorophenol, or of biodegradation of lindane (Newhook and Meek, 1994). Unlike some organochlorine (OC) compounds, including polychlorinated biphenyls (PCBs) and various pesticides, CBs are not banned from production or use in any country. (omitted)

• Bulletin of the Korean Chemical Society
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• v.18 no.11
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• pp.1183-1185
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• 1997

Dimethylamine complexes of palladium(Ⅱ) [(PCP)Pd(NHMe2)](OTf) (PCP = 2,6-(R2PCH2)2C6H3); R = Ph (1), R = Cy (2)), have been prepared from the reaction of (PCP)Pd(OTf) and dimethylamine. The complex 1 is stable both in solution and in the solid state, while 2 is stable only in solution in the presence of dimethylamine although the formation of 2 in solution is quantitative by NMR Spectroscopy. A solution NMR spectroscopic study shows that dimethylamine favors over carbon monoxide in the coordination sphere of palladium(Ⅱ) having rigid terdentate ligands. The complexes 1 and 2 in chlorinated solvents undergo a chlorine abstract reaction yielding Pd(2,6-(R2PCH2)2C6H3)Cl in the presence of a base such as dimethylamine and DABCO (diazabicyclooctane), in which a transient dimethylamido palladium(Ⅱ) species likely involves.

• Journal of Environmental Science International
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• v.17 no.1
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• pp.119-128
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• 2008

Laboratory analytical results of 22 sets of hydrophobic adsorbent coils containing surface soil-vapor and two soil samples collected by conventional intrusive method from each boring location at two active dry cleaning facilities in the State of Illinois, U.S.A, were presented to evaluate the performance of soil-vapor survey. The most critical factor to determine the effectiveness of soil-vapor survey is the distance from the soil-vapor sampling device to the actual contamination, which is a function of soil porosity, permeability, primary lithology, and other geological and hydrogeological site-specific parameters. Also this factor can be affected by the history of contaminant-generating operations. The laboratory analytical results in this study showed longer dry cleaning operation history (i.e., 50 years) and presence of fine sand at the beneath Site B allow the contaminants to migrate farther and deeper over a fixed time compared to Site A(i.e., 35 years and silty clay) so that the soil-vapor survey is not likely the most effective environmental site investigation method alone for Site B. However, for Site A, the soil-vapor survey successfully screened the site to identify the location reporting the highest soil concentration of chlorinated solvents.

• Textile Coloration and Finishing
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• v.6 no.4
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• pp.17-26
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• 1994

Poly(ethylene terephthalate)(PET) filaments were treated in binary mixtures of organic solvents such as benzyl alcohol/perchloroethylene(BA/PER), benzyl alcohol/trichloroethylene(BA/TRI), benzyl alcohol/ethylene chloride(BA/EC), methanol/perchloroethylene (ME/PER), and methanol/trichloroethylene(ME/TRI). From the equilibrium swelling of PET, total and partial isotherms of PET for sorption of solvent mixtures and isotherms for distribution of the components between the phases were taken. Also the shrinkage and the crystallinity of PET treated with binary mixtures were investigated. The results obtained were summerized as follows: 1. All isotherms for distribution of the components between the phase deviated from the diagonal in system of PET-binary mixtures. Especially in the binary mixtures of ME/PER or ME/TRI, selectivo sorption of chlorinated hydrocarbon PER and TRI by PET occured. 2. The shrinkage of PET treated in binary mixrures was increased to compare with single solvent-treated, but the composition of binary mixtures corresponding to maximum values of shrinkage was not always agreed with the composition of binary mixtures corresponding to maximum values of shrinkage was not always agreed with the composition of binary mixtures exhibiting of the maximum swelling of PET. 3. The crystallinity of PET treated in binary mixtures generally increased than that of single solvent-treated.

• Bulletin of the Korean Chemical Society
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• v.28 no.7
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• pp.1175-1182
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• 2007

A series of new organic semiconductors hexyl end-capped thiophene-anthracene oligomers containing the anthracene moiety in the center of the oligomers are synthesized. The target oligomers have been obtained by Stille coupling reactions as key step reactions. The synthesized thiophene-anthracene oligomers were characterized by 1H-NMR, 13C-NMR and high-resolution mass spectroscopy, respectively. All of the oligomers are soluble in chlorinated solvents. Their optical, thermal and electrochemical properties were measured. The hexyl end-capped oligomers and their unsubstituted oligomers exhibit the same absorption behavior in dilute toluene solution. Hexyl end-capped bis-terthienylanthracene oligomer is observed to show liquid crystalline mesophase at 166 oC in heating process. The thermal analyses as well as the electrochemical measurement data indicate that the designed materials show better thermal and oxidation stability than the corresponding oligothiophenes without anthracene core. Fluorescence lifetimes and fluorescence quantum yields of the thiophene-anthracene oligomers are measured to be 10-14 ps and 3.4-9.9 × 10?3 which are much shorter and lower than those of oligothiophenes respectively.

• Journal of the Korean Chemical Society
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• v.41 no.10
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• pp.541-546
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• 1997

Manganese dioxide may react with silicon tetrachloride to form manganese(Ⅳ) oxodichloride which reacts subsequently with another molecule of silicon tetrachloride leading to manganese tetrachloride eventually in chlorinated solvents. This in situ generated manganese(Ⅳ) oxodichloride or manganese tetrachloride were found to be very effective for the chlorination of a wide variety of alcohols to the corresponding chlorides. Primary, secondary and benzylic alcohols were converted into corresponding chlorides when treated with silicon tetrachloride in the presence of manganese dioxide at room temperature.

• Analytical Science and Technology
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• v.16 no.1
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• pp.48-58
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• 2003

The effects of physico-chemical properties of soils on PCBs analysis in Korea was studied Three kinds of extraction solvents(toluene, acetone:hexane, dichloromethane) was selected to apply three different soils. The silicagel, florisil and alumina column cleanup also performed to compare the elution patterns, and three different methods (EPA, Japan, Proposed method in this study) of 62 PCBs also compared the individual peaks recoveries. The solvent average recovery was surveyed the order of toluene, acetone:hexane, dichloromethane as 77.94%, 58.59%, 54.20% for soil A, 53.65%, 80.32%, 68.27% for soil B and 44.52%, 60.35%, 56.36% for soil C, respectively. The average recovery was depended on the soil characters. The highest recoveries of each soil were obtained the toluene for soil A, acetone:hexane for soil B and C. However, the coplanar PCBs was obtained the highest recovery with dichloromethane. Thus, to select the solvent for the analysis of PCBs in solid, the selected compounds have to consider to get good result. The silicagel, florisil, alumina I and alumina II column cleanup process were surveyed the range of 38.73%~98.26%, and the higher chlorinated compounds was obtained the lower recovery compared to the low chlorinated compounds, generally. This results are also consistent with the coplanar PCBs isomers. The compared results of three different countries were obtained the 37.15% for USA, 45.92% for Japan and 44.46% for proposed method in this study.

• Economic and Environmental Geology
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• v.34 no.3
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• pp.307-313
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• 2001

Reactive medium including zero-valent metals such as zero-valent iron ($Fe^0$) degrades chlorinated solvents as a contaminant plume flows through the treatment medium. Although the Feo based reactive barrier has been demonstnlted to be a cost effective for trichloroethenc (TCE)-contaminaled plume remediation, current approach is limited by low process eftlciency and uncertain, effective life of the medium. The objective of this study is to develop an enhanced treatment method of TeE-contaminated groundwater using Feo and direct current. The bench-scale test using flow-through $Fe^0$ reactor column confirmed that the application of direct current with $Fe^0$ is highly effective in enhancing the rate of TeE dechlorination. The dechlorination mechanism appears to be reductive, with the electrons supplied by the iron oxidation and external power supply serving as the additional source of electrons.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.1
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• pp.46-52
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• 2008

Oils and chlorinated solvents leaking to the subsurface are entrapped in the soil pore and these are called as nonaqueous phase liquids (NAPL). NAPL entrapped in porous media acts as a continuous source for surface and ground water contamination. This study visualized dissolution of trichloroethylene (TCE) entrapped in porous media and quantified the velocity of TCE dissolution using an image analysis technique. As the water velocity increased, the level of dissolution increased. The results imply that a TCE contaminated region having a high infiltration rate and groundwater velocity may result in severe groundwater contamination. Microscopic images of TCE entrapped in porous media showed that TCE present in the preferential flow paths was easily dissoluted into the water phase. However, TCE present in the stagnant flow region was visualized for long time. The results imply that TCE would be still present in the soil if TCE is detected in goundwater.

• Environmental Analysis Health and Toxicology
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• v.20 no.2 s.49
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• pp.167-178
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• 2005

This study was carried out to evaluate the temporal, spatial, and seasonal variations of VOC, and to characterize the VOC concentrations in two large industrial complexes located in Pohang and Gumi cities. Twenty -four hours continuous sampling of selected VOC was made with STS 25 sequential tube samplers and double-bed adsorbent tubes. Air samples were collected every three hour interval for 7 consecutive days in each site during summer and winter. VOC were determined by thermal desorption coupled with GC/MS. A total of 27 VOCs of environmental concern were determined, including aliphatic, aromatic and halides. Generally. concentrations of toxic VOC were higher in Gumi than Pohang, and VOC levels in industrial areas were typically several-fold higher than those in residential areas. The most abundant VOC appeared to be toluene for both cities. However, chlorinated VOC were higher in Gumi than Pohang, while aromatic VOC were more abundant in Pohang than in Gumi. Two cities showed relatively different variations of VOC concentrations within a day. It is likely that traffic related sources are major factors affecting the VOC in Pohang, and industrial solvents usages are important sources in Gumi. These results imply that the occurrence and levels of atmospheric VOC are strongly dependent on the type of industries in each city. Therefore, in order to develop any control strategies or to establish the priority rankings for VOC in large industrial complexes, the type of industries and the occurrence of VOC in the atmosphere should be taken into consideration.