• Bulletin of the Korean Chemical Society
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• v.19 no.11
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• pp.1222-1227
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• 1998

The crystal structure of a benzene sorption complex of fully dehydrated Cd2+-exchanged zeolite X, Cd46Si100Al92O384·43C6H6 (a=24.880(6) Å), has been determined by single-crystal X-ray diffraction techniques in the cubic space group Fd3 at 21 ℃. The crystal was prepared by ion exchange in a flowing stream of 0.05 M aqueous Cd(NO3)2 for 3 d, followed by dehydration at 400 ℃ and 2 x 10-6 Torr for 2 d, followed by exposure to about 92 Torr of benzene vapor at 22 ℃. The structure was determined in this atmosphere and refined to the final error indices R1=0.054 and Rw=0.066 with 561 reflections for which I > 3σ(I). In this structure, Cd2+ ions are found at four crystallographic sites: eleven Cd2+ ions are at site 1, at the centers of the double six-oxygen rings; six Cd2+ ions lie at site I', in the sodalite cavity opposite to the double six-oxygen rings; and the remaining 29 Cd2+ ions are found at two nonequivalent threefold axes of unit cell, sites Ⅱ' (in the sodalite cavity ) and site Ⅱ (in the supercage) with occupancies of 2 and 27 ions, respectively. Each of these Cd2+ ions coordinates to three framework oxylkens, either at 2.173(13) or 2.224(10) Å, respectively, and extends 0.37 Å into the sodalite unit or 0.60 Å into the supercage from the plane of the three oxygens to which it is bound. The benzene molecules are found at two distinct sites within the supercages. Twenty-seven benzenes lie on threefold axes in the large cavities where they interact facially with the latter 27 site-Ⅱ Cd2+ ions (Cd2+-benzene center=2.72 Å; occupancy=27 molecules/32 sites). The remaining sixteen benzene molecules are found in 12ring planes; occupancy=16 molecules/16 sites. Each hydrogen of these sixteen benzenes is ca. 2.8/3.0 Å from three 12-ring oxygens where each is stabilized by multiple weak electrostatic and van der Waals interactions with framework oxygens.

• Journal of Photoscience
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• v.1 no.1
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• pp.39-45
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• 1994

Haloarene in which the phenyl group and halophenyl group are connected by alkyl groups were synthesized to study the photochemical behavior. The photochemical reactions of 1-halo-2-(phenylalkyl)enzenes (1 and 2) were studied in several aerated or unaerated solvents. In the case of 2-benzyl-1-halobenzene photoreduced product (biphenyl) is major in acetonitrile or benzene. In cyclohexane or acetonitrile with triethylamine, photoreduced product is obtained exclusively, while in acetonitrile with toluene, xylene, or sodium hydroxide photocyclized product (fluorene) is mainly obtained. In the case of 1-halo-2-phenethylbenzenes (5 and 6), photocyclized product (9,10-dihydrophenanthrene and phenanthrene) are major in acetonitrile or benzene. While the haloarenes 1 or 2 connecting the two arene rings by methylene is photoreduced, the other haloarene 5 or 6 connecting by ethylene is photocyclized. In cyclohexane or acetonitrile with a small amount of triethylamine, photoreduced reactions of 5 or 6 mainly occur. In acetonitrile with sodium hydroxide, toluene, or xylene, photocyclization of 5, 6 occur exclusively. The triplet state is mainly involved in the photocyclization of 5 or 6, because of the inhibition of oxygen.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.11a
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• pp.129-135
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• 2000

Four types of land use were selected for sampling and study with different characteristics of heavy metal contamination during the period from August 1998 to June 2000. A series of studies have been carried out concerning the physicochemical characteristics of the sediments settling down in a gully pot to evaluate the contamination of Pb, Zn, Cd, Co, Cr and Cu. An examination of six elements indicated that Zn, Cu and Pb were the heavy metals severely impacted by anthropogenic input in Seoul. An assessment of 60 volatile organic compounds (VOCs) in urban runoff and ground water was conducted based on samples collected from 31 sites and 12 wells, respectively, in Seoul City. The higher levels of alkyl benzenes in urban runoff indicated that Seoul areas were mainly contaminated through traffic sources.

• Korean Journal of Food Science and Technology
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• v.25 no.5
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• pp.494-501
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• 1993

The volatile flavor components of traditional and commercial kochujang were collected by simultaneous steam distillation-extraction (SDE) method. Essential oils were analyzed by gas chromatography (GC) and combined gas chromatography-mass spectrometry (GC/MS). Tested kochujang included Sunchang kochujang prepared with glutinous rice, Boeun kochujang prepared with barley, Sachun kochujang prepared with wheat and commercial kochujang. One hundred and twelve volatile flavor components which included 30 esters, 15 alcohols, 14 aldehydes, 13 acids, 9 ketones, 7 alkenes, 6 phenols, 3 alkanes, 3 pyrazines, 2 benzenes and 2 furans were identified. The major volatile compounds in traditional and commercial kochujang were 2-methyl propanal and ethanol, which represented $21{\sim}36%\;and\;2{\sim}44%$ of total GC peak area, respectively.

• Bulletin of the Korean Chemical Society
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• v.25 no.12
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• pp.1932-1934
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• 2004

• Bulletin of the Korean Chemical Society
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• v.17 no.6
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• pp.506-510
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• 1996

The syntheses and photoreactions of haloarenes, in which the aryl and haloaryl moieties are tethered by a simple alkyl group, were studied. For 2-benzyl-1-halobenzene, in which two aryl moieties were connected by methylene group, photoreduced product, diphenylmethane, was obtained along with the minor formation of the photocyclized product, fluorene, in acetonitrile solvent. For 1-halo-2-phenethylbenzene, in which two aryl moieties were connected by ethylene group, photocyclized products, 9,10-dihydrophenanthrene and phenanthrene, were obtained along with the minor formation of photoreduced product, bibenzyl, in acetonitrile solvent. The photoreaction selectivities in several solvent systems were studied: In cyclohexane, 2-benzyl-1-chlorobenzene was photoreduced more effective than 2-benzyl-1-bromobenzene; In the presence of NaOH, 1-halo-2-phenethylbenzenes gave 9,10-dihydrophenanthrene and, in the presence of toluene, they gave phenanthrene. A radical reaction mechanism is proposed for the explanation of the reactions. This study shows that the photoreaction of haloarene, in which haloaryl and aryl moieties are tethered by ethylene group, can be used for ring formation of 9,10-dihydrophenanthrene otherwise difficultly accessible.

• Bulletin of the Korean Chemical Society
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• v.14 no.5
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• pp.618-620
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• 1993

Treatment of (dichloromethyl)benzenes with CO (1 atm) in the presence of catalytic amount of $Co_2(CO)_8,\;Fe(CO)_5$ and BTEAC under two phase systems with NaOH(_{aq}) and $PhCH_3$ containing small amount of alcohol for 20 hours at 80$^{\circ}$C gives phenylacetic acids in moderate yields.

• Journal of the Korean Magnetic Resonance Society
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• v.26 no.4
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• pp.40-45
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• 2022

A small cage-like molecule (2) composed of three aminomethyl pyrroles and two hexa-substituted benzenes has been prepared by reduction of its iminopyrrole analogue (1) using NaBH₄. It was revealed by ¹H NMR spectroscopic analyses that cage molecule 2 strongly binds the fluoride anion in polar DMSO-d₆ relative to CDCl₃. Compared to that of compound 1, the lowered affinity of 2 for the fluoride anion is attributable to its increased electron density resulting from the production of thesecondary amine groups.

• Analytical Science and Technology
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• v.6 no.1
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• pp.1-8
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• 1993

The purpose of this study is to investigate the elution behavior of monosubstituted phenols and benzenes in micellar liquid chromatographic system, $C_{18}$ column-anionic surfactant, sodium dodecyl sulfate(SDS). The partition coefficients between the micellar pseudophase-water and modified stationary phase-water are calculated by the relationship between solute retention and micellar mobile phase(SDS) composition. The free energy of transfer of solute from water to micelle is also calculated from these values. There is a direct correlation between the hydrophobicity parameters in MLC and corresponding partition data for 1-octanol-water, which indicates that the hydrophobicity of molecules plays an important role in the partition for both systems and that quantitative structure activity relationships(QSAR) are available from studies on micellar partition. The other purpose of this study is to investigate methylene selectivity of alkyl homologous series through correlation between retention and the number of carbons. The correlation between hydrophobicity parameters in MLC and 1-octanol-water partition data was also observed when n-propanol was as a modifier in the mobile phase.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.6
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• pp.731-737
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• 1992

The specific attributes of aroma quality of canned tuna meat were investigated before and during refrigerated storage. Fresh, cooked tuna, beefy and meaty flavor notes of canned tuna meat were changed to card-boardy(1 week storage), oxidized fat-like(2 weeks storage), fatty acid-like and heavy oxidized fat-like(3 weeks storage), and then moldy and painty(4 weeks storage) flavor notes during storage in refrigerator at $4^{\circ}C.$ More than 126 peaks of volatile compounds collected from canned tuna meat were separated on Carbowax 20M capillary column of gas chromatographic analysis. Of the peaks, 54 compounds were identified by mass spectral data, matching $I_E$ values, and sniffing the effluent of each peak from GC detector. The contents of many low molecular weight compounds eluted with early retention times were decreased, whereas some other new compounds eluted with longer retention time were formed during storage. The compounds increased up to 3 weeks of storage and then decreased at extended storage time(4 weeks) were 1-penten-3-ol, 3-penten-2-ol, heptanal, limonene, 1-pentanol, octanal, 1-hexanol, nonanal, 2-octanone, 2-nonanone, 1-heptanol, benzaldehytde and some methyl substituted benzenes. p-Thiocresol, 2-chlorophenol, and 2-heptylthiophene were formed after 4 weeks of storage, but not detected in fresh canned tuna. Therefore, these compounds could be used as indicators for the quality changes during refrigerated storage.