• 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

• Applied Chemistry for Engineering
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• v.21 no.2
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• pp.230-237
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• 2010

A homologous series of linear liquid crystal dimers, ${\alpha},{\omega}$-bis(4-nitroazobenzene-4'-carbonyloxy)alkanes (NATWESn, n = 2~8, 10, the number of methylene units in the spacer) have been synthesized, and the thermal behavior of the series has been investigated. All the dimers formed enantiotropic nematic phases. The nematic-isotropic transition temperatures of the dimers and their entropy variation at the phase transition showed a large odd-even effect as a function of n. This behavior was rationalized in terms of the change in the average shape of the spacer on varing the parity of the spacer. The thermal stability and degree of order in the nematic phase and the magnitude of the odd-even effect of NATWESn were very similar to those of the corresponding ether compounds, while they were significantly different from those of the monomesogenic compounds, 4-{4'-(nitrophenylazo)phenoxy}alkanoyl chlorides and the side-chain liquid-crystalline polymers, the poly[1-{4-(4'-nitrophenylazo) phenoxycarbonylalkanoyloxy}ethylene]s. The results were discussed in terms of the 'irtual trimer model'by Imrie.

• Applied Chemistry for Engineering
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• v.4 no.3
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• pp.474-481
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• 1993

The infinite dilution activity coefficients(${\gamma}{\infty}$) of nonpolar and polar solutes have been determined in different solvents at temperature between 60 and $100^{\circ}C$ by using gas chromatography. The $ln{\gamma}{\infty}$ values of nonpolar solutes(alkanes, cyclohexane, benzene, toluene and $CCl_4$) were linearly increased as 1/T in the nonpolar solvent (n-octadecane) and the polar solvent(n-hexadecyl alcohol) systems and the $ln{\gamma}{\infty}$ values at the constant temperature were increased with the number of carbon atoms of solute molecule. For the polar solutes(alcohols, esters and ketones) and the weak polar solvent(di-2-ethyl adiphate and di-2-ethylhexyl sebacate) systems, the relations of $ln{\gamma}{\infty}$ vs. 1/T were found to be curved with increased slope, and the $ln{\gamma}{\infty}$ values at constant temperature were linearly diminished as increasing the number of carbon atoms of solute molecule. For the polar solutes(alcohols, esters and ketones) and the strong polar solvents(triphenyl phosphate and tricresyl phosphate)systems, the relations of $ln{\gamma}{\infty}$ vs. 1/T were found to be curved with increased slope but $ln{\gamma}{\infty}$ values at constant temperature were linearly increased as increasing the number of carbon atoms of solute molecule.

• Applied Chemistry for Engineering
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• v.19 no.1
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• pp.59-65
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• 2008

The equilibrium solubilization capacity of the mixture of hydrocarbon oils by $C_{12}E_8$ nonionic surfactant micellar solution was measured at $23^{\circ}C$ by gas chromatography (GC) analysis. Experimental results indicated that the solubilization capacity for pure alkanes was found to decrease almost linearly with the alkane carbon number (ACN) of the hydrocarbon oil. For the binary mixture systems of the hydrocarbon oils both selective and nonselective solubilization behaviors were observed depending on the difference in ACN of the two hydrocarbon oils. Equilibrium solubilization tests for the hydrocarbon oil mixtures in $C_{12}E_8$ surfactant solutions such as the three n-octane/n-nonane, n-nonane/n-decane and n-decane/n-undecane mixture systems suggest almost non-selective solubilization. On the other hand, the n-octane/n-decane and n-octane/n-undecane systems, where difference in ACN of the two hydrocarbon oils is greater than 1, selective solubilization in favor of n-octane was conclusively demonstrated.

• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.1
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• pp.120-127
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• 2002

This study was carried out to evaluate the effects of initial concentration on composting of diesel-contaminated soil. Silt loam was used in this study. Target contaminant, diesel oil, was spiked at about 2,000, 4,000, and 10,000mg/kg of dry soil, respectively. Mix ratio of soil to sludge was 1:0.3 as wet weight basis. Temperature was maintained at $20^{\circ}C$ Volatilization loss of TPH was 0.7-3.5% of the initial concentrations. Volatilization loss of TPH was not increased in proportion to the initial concentration. After 30 days of operation, 86% and 94% of the initial concentrations at about 2,000 and 10,000mg TPH/kg were biodegraded. Normal alkanes were degraded more rapidly than TPH. The compounds of C12 to C14 were volatilized greatly among n-alkanes. The first order degradation rate constants of about 2,000, 4,000, and 10,000mg TPH/kg were 0.079, 0.069, and 0.061/day, respectively. Produced-$CO_2$ and degraded-TPH were correlated highly regardless of the initial TPH concentration(r = 0.97-0.99).

• Korean Chemical Engineering Research
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• v.45 no.3
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• pp.219-225
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• 2007

The equilibrium solubilization capacity of pure hydrocarbon oils by 2.5 wt% $C_{12}E_8$ nonionic surfactant solution was measured at $30^{\circ}C$ by gas chromatography (GC) analysis. Experimental results indicated that the molar solubilization ratio (MSR) for pure alkanes was found to decrease almost linearly with the alkane carbon number (ACN) of the hydrocarbon oil. For the binary mixture systems of the hydrocarbon oils both selective and nonselective solubilization behaviors were observed depending on the difference in carbon number of the two hydrocarbon oils. Equilibrium solubilization tests for the two n-octane/n-nonane and n-nonane/n-decane mixture systems in $C_{12}E_8$ surfactant solutions suggest slightly selective solubilization in favor of n-octane, but the small difference in solubilization rates between two hydrocarbon oils does not allow ruling out non-selective solubilization for these particular systems. This is certainly not the case for the n-octane/n-decane mixture, for which selective solubilization was conclusively demonstrated by GC analysis data.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.7
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• pp.721-730
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• 2006

The effects of compost amendment on the removal of petroleum hydrocarbons and the activities of microorganisms in soil ecosystem have been studied in bioremediation of diesel contaminated soil. The relation between biological activities and removal of petroleun hydrocarbon was determined by ATP(Adenisine Triphosphate), n-alkanes and TPH concentration analysis. After 80 days of bioremediation, the removal of TPH in soil amended with compost increased more than 10% compared with control soil which was tilled in the same condition without compost addition. The biodegradations of n-alkanes having 12 to 20 moles of carbon were distinctive. As the soil was contaminated with more diesel, the ATP has decreased rapidly. When the TPH amounted to 80,000 mg diesel/kg, the ATP decreased to 4 ng/g from initial concentration of 65 ng/g. While the ATP in the compost amended soil increased to 112 ng/g after tilling for 6 days, the ATP in the control increased to merely 36 ng/g after tilling for 14 days. Also while the control soil showed a lag time in ATP increase, the compost amended soil did not show that but showed a rapid ATP increase within a short time. The patterns of changes in ATP concentration were similar to those in daily removals of TPH with time difference of about 7 days.

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1703-1707
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• 2013

A fast and simple sampling and sample preparation device, (NTD) has been developed and applied to sample and analyze volatile components from ground coffee beans. Coffee fragrances and other volatile organic compounds (VOCs) were sampled by the NTD and then analyzed by gas chromatograph-mass spectrometry (GC/MS). Divinylbenzene (DVB) particles (80/100 mesh size) were the sorbent bed of the NTD. More than 150 volatile components were first identified based on the database of the mass library and then finally 30 fragrances including caffeine were further confirmed by comparing experimental retention indices (i.e. Kovat index) with literature retention indices. Total sampling time was 10 minutes and no extra solvent extraction and/or reconstitution step need. Straight n-alkanes (C6-C20) were used as retention index probes for the calculation of experimental retention indices. In addition, this report suggests that an empty needle can be an alternative platform for analyzing polymers by pyrolysis-GC/MS.

• Preventive Nutrition and Food Science
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• v.13 no.1
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• pp.18-22
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• 2008

Volatile components in field bean (Dolichos lablab) were collected by simultaneous steam distillation and solvent extraction and analyzed by gas chromatography-mass spectrometry. One hundred and five components were identified including alcohols (32), ketones (18), aldehydes (9), acid (1), alkanes (5), aromatics compounds (4), esters (2), furans (2), naphthalene (1), pyrazines (4), pyridine (3), sulfur-containing compounds (4) and terpenes (7) and miscellaneous compounds (13). Relatively high concentration of n-hexanal found in the field bean might be undesirable to some consumers.

• Journal of environmental and Sanitary engineering
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• v.15 no.4
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• pp.44-51
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• 2000

The reactivity of a range of volatile organic compounds with differing functional groups observed over 0.5% $Pt/{\gamma}-Al_2O_3$ catalyst. In general, the reactivity pattern observed was alcohols > aromatics > ketones > cycloalkane > alkanes. The deep conversion was increased as reaction temperature was increased. A correlation was found between the reactivity of the individual and the strength of the weakest C-Hbond in structure. The conversion of volatile organic compounds increases in order methanol > benzene > cyclohexane > MEK > n-hexane. That is the effect of differences in total dissociation energy. An apparent zeroth-order kinetics with respect to inlet concentration have been observed. A simple multicomponent model based on two-stage redox model made reasonably good predictions of conversion over the range of parameters studied. thus, the catalytic process was suggested as the new VOCs control technology.