• Korean Chemical Engineering Research
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• v.55 no.5
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• pp.660-667
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• 2017

Equilibrium data of the mixture is essential in the design and operation of separation equipment such as distillation or extraction in chemical processes. These equilibrium data can be obtained through experiments or by calculations using the known binary parameters and the thermodynamic models. Generally, to obtain these parameters, phase equilibrium experimental data such as gas-liquid and liquid-liquid are used. In this study, the excess enthalpy of the mixture was measured using the flow type microcalorimeter which is a simpler method than phase equilibria experiments, and the parameters of various theories were obtained by using this data. In order to investigate the relationship between carbon chain length, enthalpy and binary parameters in the alkane system, excess enthalpies for the n-hexane + alkane (n-pentane, n-heptane, n-octane and n-dodecane) were measured at 298.15 K and the banary interaction parameters of Wilson, NRTL, and UNIQUAC were obtained from the experimental data. In addition, we wanted to obtain basic information on the interaction and association phenomena of the system including electrolyte applicable to various fields by using the excess enthalpy experimental data and the existing theory. First, we investigated the excess enthalpy for the NaOH / Water / Ethanol system as a basic experiment and examined the applicability using the electrolyte-NRTL (eNRTL) theory.

• Applied Chemistry for Engineering
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• v.3 no.4
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• pp.579-587
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• 1992

It was explored, whether the usual course of the ozonolysis of olefins can be modified with the help of pyridine. In the First step, the ozone oxidation of trans-3-hexene was performed with and without pyridine in the inert solvents n-pentane and dichloromethane. In addition, base catalyzed decompositions of monomeric and polymeric ozonides were also examined to identify the reaction mechanism. The reaction products were identified by modern analytical tools. The results of this work showed that reactions of ozone with olefins in the absence of pyridine in aprotic solvents gave, one hand, dominantly peroxidic products, namely monomeric and polymeric ozonides. The other hand, they in the presence of pyridine gave only the non-peroxidic products, namely propionaldehyde and rearranged propionic acid without peroxidic products. It seems, also, that the pyridine-catalyzed isomerization of the Criegee zwitterion of trans-3-hexene to give propionic acid takes place in the ozone oxidation of trans-3-hexene.

• The Korean Journal of Food And Nutrition
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• v.14 no.1
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• pp.15-19
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• 2001

An attempt was made in this study to analyze volatile flavor components of A. macrocephala Koidz. and A. lanacea DC. (Atractylodes japonica Koidzumi). Essential oils in A. macrocephala Koidz. and. A. lanacea DC. were isolated by a simultaneous steam distillation and extraction(SDE) method using n-pentane/diethy ether as solvent. A total of 30 and 28 components were identified by GC/MS from the essential oils of A. macrocephala Koidz. (18 hydrocarbons. 2 carbonyls, 5 alcohols, 5 esters) and A. lanacea DC.(14 hydrocarbons, 6 carbonyls, 4 alcohols, 3 esters, 1 acids), respectively. The major volatile flavor components in A. macrocephala Koidz. and A. lanacea DC. were furanodiene(27.9%, 15.7%), $\alpha$-cyperone(8.1%. 22.5% ), alloaromadendrene(2.9%, 4.7% ), (1,1-biphenyl)-4-carbon aldehyde 0%, 8.7% ) were found, respectively. Ten components including limonene, p-cymene, p-hymen-8-ol, (1,1-biphenyl)-4-carbox aldehyde were identified in A. lanacea DC, but not in A. macrocephala Koidz. and eight components including $\alpha$-copanene, isocaryophyllene, $\beta$-himahalene. germacrene B were and identified in A. macrocephala Koidz. but not in A. lanacea DC.

• Korean Journal of Food Science and Technology
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• v.21 no.1
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• pp.127-135
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• 1989

The volatile components of nutmeg, cumin, cardamon, turmeric, coriander, clove, allspice, cassia, fennel, celery seed and black pepper, having a characteristic spicy aroma and being used as an ingradient of curry powder, were investigated. After steam distillation followed by extraction with diethyl ether: n-pentane(2:1, v/v) mixture, the volatile components were identified by capillary GC and GC/MS. As a result, following major compounds were identified. ${\alpha}-pinene(11.06%)$, ${\beta}-pinene(11.17%)$ and myristicin(19.98%) in nutmeg, cuminaldehyde(37.68%) in cumin, ${\alpha}-terpineol(47.33%)$ and 1, 8-cineol(20.56%) in cardamon, linalool(61.72%) in coriander, eugenol(63.63%) and eugenol acetate(20.59%) in clove, eugenol(80.12%) and methyl eugenol(10.85%) in allspice, cinnamaldehyde(82.29%) in cassia, anethole(79.92%) in fennel.

• Korean Journal of Food Science and Technology
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• v.24 no.5
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• pp.423-427
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• 1992

The volatile components were extracted from kumquat(Fortunella margarita) by simultaneous steam distillation-extraction method and fractionated on silica gel column. The total volatile oil was eluted off first by n-pentane and eluted again by diethyl ether. The total volatile oil and diethyl ether fraction were analyzed by GC and GC-MS. In the total volatile oil, 10 components were identified, of which major ones were limonene(96.5%, of total volatile oil), ${\beta}-pinene$(1.93%) and ${\alpha}-terpineol$(0.42%) and then the characteristic aroma of kumquat appeared to be due to limonene. On the other hand diethyl ether fraction, from which 46 components were identified, contained 9 alcohols, 22 terpenes and terpene alcohols, 7 aldehydes and ketones, 7 esters and 1 miscellaneous components. The major components were ${\alpha}-terpineol$(31.98% of diethyl ether fraction), ${\beta}-terpineol$(7.37%), geranyl acetate(9.69%) and p-menthadien-9-ol(4.12%).

• Journal of the Korean Chemical Society
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• v.33 no.1
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• pp.46-54
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• 1989

The extraction method and quantitative analysis for the fat-soluble vitamins present in food stuffs and vitamin products have been investigated. The simultaneous separation and analysis of the vitamins by reverse phase high performance liquid chromatographic method was conducted using an isocratic elution with methanol : water (95 : 5) eluent on a Novapak $C_{18}$ column. The detection of vitamins was achieved by a variable wavelength UV detector. To improve the detection sensitivity detection wavelengths were set at the highest absorption bands such as 330, 265, 285, and 290nm for the respective vitamins. The analysis for the fat-soluble vitamins was finished within 40 minutes. Alkaline hydrolysis and enzymatic hydrolysis were investigated for the sample preparation; and liquid-liquid extraction and liquid-solid extraction were attempted for the extraction of vitamins. Both hydrolysis methods were turned out to be appropriate for the analysis for vitamins A, D, and E, while for the analysis of vitamin K the enzymatic hydrolysis method demonstrated better results. Diethyl ether, pentane, and n-hexane were found to give higher recovery for the liquid-liquid extraction and silica cartridge for the liquid-solid extraction.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.E3
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• pp.129-136
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• 2003

Effects of inorganic aerosols on the kinetics of the hydroxyl radical reactions with selected aliphatic alkanes have been investigated using the relative rate technique. The relative rates in the absence and presence of aerosols were determined for n-butane, n-pentane, n-hexane, n-octane, and n-decane. P-xylene was used as a reference compound. Inorganic aerosols including (NH$_4$)$_2$SO$_4$, NH$_4$NO$_3$, and NaCl aerosols at two different aerosol concentrations that are typical of polluted urban conditions were tested. Total surface areas of aerosols were 1400 (Condition I) and 3400 $\mu$$m^2$ cm$^{-3}$ (Condition II). Significant changes in the relative rates in the presence of the inorganic aerosols were not observed for the n-butanel/$.$OH, n-pentanel/$.$OH, n-hexanel/$.$OH, n-octanel/$.$OH, and n-decanel/$.$OH reactions versus p-xylenel/$.$OH reaction. These results suggest that the promoting effects depend on the semiconducting property of the aerosols and the nature of the organic compounds.

• Journal of the Korean Applied Science and Technology
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• v.31 no.1
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• pp.151-158
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• 2014

Asphaltenes are generally defined by their solubility when a light alkane, such as n-heptane or n-pentane, is mixed with crude oils or oil sand bitumen. However, this definition is nowadays not enough to understand their behaviors during oil recovery, transport, storage, and even refinery operation. Interestingly, the researches regarding asphaltenes have been vastly presented within last decade. This is because the production of heavy oils is becoming larger and asphaltenes are known to play an important role in the property changes of heavy oils. In this paper, the researches regarding molecular weight, aggregation behavior of asphaltenes are introduced and discussed. It is expected that analytical studies will be appeared continuously in the form of global collaboration in order to describe asphaltene molecules as close as possible based on their origin.

• Journal of the Korean Chemical Society
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• v.38 no.8
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• pp.570-575
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• 1994

The metallation of $\alpha$-methylpyridine 1(a∼f) with n-BuLi produced $\alpha-methylenylpyridinium$ salt 3(a∼f) by elimination of butane. The trapping reactions of 3(a∼f) with $Me_3SiCl\;and\;Me_2SiClCH(SiMe_3)CH_2tBu$ produced only 4(a∼f) and 5(a∼f). The $\alpha$-hydrogen atom of silylated methylene group in 4(a∼f) is more reactive than unreacted $CH_3$ of 4(a∼f) itself and 1(a∼f) toward n-BuLi at low temperature in pentane medium.

• Journal of the Korean Chemical Society
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• v.7 no.2
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• pp.128-132
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• 1963

A study has been made on the applicability of gas-liquid partition chromatography to the qualitative and quantitative analysis of complex mixture of gaseous hydrocarbons. While phthalate columns are widely used for this $purpose^9$, they separates neither saturated hydrocarbons from the unsaturated nor n-butane from isobutene or butene-1, therefore combined columns such as phthalate and dimethylsulfolane have been used for the perfect separation of gaseous hydrocarbons. It is shown by this study, however, that hydrocarbons having $C_1$ through $C_4$ can be separated with a 2-meters tetraethyleneglycol dimethylether column except ethane from ethylene, and trans-from cis-2-butene especially operated at $15^{\circ}C$$ using helium as the carrier gas. The column effluents were in order of methane, (ethane, ethylene), propane, propylene, isobutane, n-butane, isobutylene, butene-1, (trans-& cis-2-butene, isopentane), (butadiene-1, 3, n-pentane). Two kinds of liquified petroleum gases in market are analysed qualitatively and quantitatively. The results indicate that use of this 2-meters TEGDE column permits the separation and identification of all the commonly encountered aliphatic gaseous hydrocarbons.