• Applied Chemistry for Engineering
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• v.9 no.1
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• pp.76-81
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• 1998

Physical adsorption on a silica gel(pore size of 80 nm, particle size of $10{\mu}m$)has been studied for binary mixture of acetone diluted in $CO_2$ by use of a FTIR transmission technique and we have compared the result of FTIR transmission technique with that of a chromatographic technique. Measurements were made at 313.2 K and under pressures up to 15MPa. As the pressure increases from 0.1MPa, the IA(Integral Absorbance) of the hydrogen-bonded OH groups interacting with acetone and adsorbed amount by use of a chromatographic technique increases at first, and reaches a maximum at a pressure below the critical pressure of $CO_2$, and then the intensities decrease gradually with increasing pressure. It is found that the pressure dependency of the chromatographic isotherm is a little larger than that of spectroscopic isotherm in the supercritical fluid region. This difference might be attributable to the weaker van der Waals force and relatively stronger hydrogen-bonding force influencing the adsorption of acetone on the sllica gel. The unique spectroscopic characteristics of amine group which vibrational frequencies of hydroxyl groups on the silica gel surface shift downward to about $1300cm^{-1}$ were measured from experimental result of triethylamine diluted in $CO_2$ or $N_2$.

• Journal of Food Hygiene and Safety
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• v.26 no.1
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• pp.36-42
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• 2011

In order to optimize the supercritical fluid extraction (SFE) conditions of ginger oleoresin (GO), we conducted an evaluation of quality properties such as yield (%), color, volatile flavor compounds and gingerol components. The extraction yield gained by SFE increased as extraction pressure and temperature increased. The highest yield was $8.96{\pm}0.68%$ at 500 bar $65^{\circ}C$ extraction condition. The total color difference (${\Delta}E$) values decreased at high pressure. In case of the 100 bar pressure conditions, ${\Delta}E$-values increased as the temperature went up. The analysis of the 6-gingerol, 8-gingerol, 10-gingerol, 6-shogaol and curcumin contents decreased at high temperature conditions of identical pressure and increased at high pressure conditions. The volatile flavor compounds were detected in zingiberene, ${\beta}$-sesquiphellandre, ${\beta}$-phellandre, ${\alpha}{\gamma}$-curcumene, 2,3-butandiol, ${\beta}$-bisabolene and so on. Also volatile component contents showed difference in each of extraction conditions.

• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1268-1274
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• 1999

Pine twigs with buds were cut into $2{\sim}3\;mm$ long pieces and about 18g was used for each experiment. Pressure and temperature ranges employed were $100{\sim}300\;bar$ and $35{\sim}55^{\circ}C$, respectively. Volatile compounds of extracts were isolated and identified by gas chromatography and mass selective detector. Twenty three compounds from the extracts were identified. Limonene and ${\beta}-pinene$ were found to be the major components with $32.6{\sim}43.4%$ being limonene. Extracts obtained by supercritical fluid extraction were lower in monoterpene and higher in oxygenated terpenoids than those by steam distillation and solvent extraction (SDE). Sensory evaluation showed that the pine flavor extracted using supercritical carbon dioxide was much better in quality than that of SDE. In conclusion, it was found out that supercritical fluid extraction can successfully be applied to extract high quality flavor from pine.

• Polymer(Korea)
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• v.32 no.1
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• pp.13-18
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• 2008

For the evaluation of brominated flame retardants included in polymeric electronic devices, we investigated the extraction methods and solvent systems for four different types of polymers of PC (polycarbonate), PP (polyropylene), PET (poly(ethylene terephthalate)) and PBT (poly(butylene terephthalate)) using different solvent systems of hexane/acetone, THF, toluene, and THF/toluene. In order to compare the extraction efficiency of different methods and solvent systems, the deca-BDE (decabromo diphenyl ether) flame retardant was included in PC, PP, PET and PBT systems and subsequently extracted by soxhlet, ultrasonic, accelerated solvent, microwave and supercritical fluid extraction methods. The amount of the extracted flame retardant was monitored to evaluate the extraction efficiency. The ultrasonic extraction method was found not to be acceptable as an extraction method for the polymer systems mainly due to a low salvation efficiency of the organic solvents. Soxhlet, accelerated solvent and microwave extraction methods exhibited over 80% of extraction efficiency for toluene. The supercritical fluid extraction method, which has been used as an extraction method for flame retardants in polymers, showed the extraction efficiencies of ca. 100% for PC and PP in the optimal extraction conditions of $60^{\circ}C$ and 120 bar.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.251.1-251.1
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• 2010

바이오디젤은 동식물성 기름과 메탄올의 트랜스에스테르화 반응에 의해 생산되는 지방산메틸에스테르(FAME, fatty acid methyl esters)로서, 트랜스에스테르화 공정에는 KOH, NaOH, $NaOCH_3$등의 균질계 화학촉매를 이용한 방법, 무촉매 공정인 초임계 메탄올 이용 방법, 그리고 효소촉매를 이용한 방법이 있다. 초임계 공정은 에너지 소비와 장치비가 커서 경제성이 떨어지는 것으로 보고되며 화학촉매 공정은 반응 효율이 높다는 장점을 가지고 있지만, 반응 및 정제단계가 복잡하고 정제과정에 폐수를 발생시키는 문제점을 가지고 있다. 고정화 효소를 사용하는 효소 공정은 에너지 비용의 절감, 후 처리 공정의 단순화, 고 순도의 글리세롤을 얻을 수 있는 장점이 있지만, 반응 속도가 느리고 효소 가격이 비싸다는 단점이 있어 현재까지 상업화되지 못하고 있다. 반응속도가 높고 재사용이 가능한 효소 촉매 공정 개발을 위해 본 연구에서는 Candida rugosa, Rizhopus oryzae 2종을 실리카에 동시 고정화하였다. 고정화 Lipase의 제조는 실리카겔을 과산화수소를 이용하여 전처리를 하고 Acetone과 3-APTES의 혼합용액을 첨가한 후 실리카겔과 (silanization)을 진행 하였다. 그리고 glutaraldehyde를 첨가 하여 공유 결합을 형성 한 후에 증류수를 사용하여 실리카겔을 회수하여 lipase(Rizhopus oryzae, Candida rugosa 10% 용액)를 고정화 하였다. 고정화 효소의 효소 활성을 측정한 결과 3000-3500 Unit(${\mu}mol/g{\cdot}min$)으로 측정되었다. 제조된 고정화 효소를 이용하여 Canola Oil을 바이오디젤로 전환하는 실험을 진행하였으며 생성물로부터 고정화 효소를 분리한 후에 상층의 에스테르층을 취하여 수세한 뒤 원심분리하여 FAME 함량을 측정한 결과 83%의 바이오디젤을 얻을 수 있었다. 그리고 효소 촉매 트랜스에스테르화 반응의 Enzyme, Water, Methanol 투입량의 반응 변수들에 대하여 반응표면분석법(Response Surface Methodology)을 적용하여 최적 반응조건을 도출하는 연구를 수행하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.7
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• pp.85-93
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• 2003

Droplet vaporization at various ambient pressures is studied numerically by formulating one dimensional evaporation model in the mixture of hydrocarbon fuel and air. The ambient pressure ranged from atmospheric conditions to the supercritical conditions. The modified Soave-Redlich-Kwong state equation is used to account for the real gas effects in the high pressure condition. Non-ideal thermodynamic and transport properties at near critical and supercritical conditions are considered. Some computational results are compared with Sato's experimental data for the validation of calculations. The comparison between predictions and experiments showed quite a good agreement. The droplet lifetime increases with increasing pressure at temperature lower than the critical temperature, however, it decreases with increasing pressure at temperature higher than the critical temperature. The solubility of nitrogen can not be neglected in the high pressure and it becomes higher as the temperature and the pressure go up.

• Clean Technology
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• v.16 no.4
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• pp.239-244
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• 2010

The carboxylation of the fluorenyl epoxide with a spiro framework, 9,9'-Bis(4-oxiranylmethoxyphenyl) fluorine (2) was catalyzed by some onium salts such as quaternary ammonium and phosphonium salts to produce the corresponding five-membered cyclic carbonate (3) in an efficient and environmentally benign fashion. The coupling reactions depend greatly on the kind of the halide anions and alkyl chain length of the onium salts. While the reaction was sensitive to the reaction temperature, the reaction trends suggest that the catalytic efficiency of the quaternary ammonium halides may correlate strongly with the melting points of the halides. The reactions using a catalytic amount (2 mol %) of quaternary ammonium bromide with an n-butyl chain at 75.9 bar of $CO_2$ and 393 K give the highest yield of the cyclic carbonate (92%).

• Korean Journal of Food Science and Technology
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• v.42 no.4
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• pp.475-480
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• 2010

The fruit of Actinidia polygama, Mock-chun-ryo in Korea, has been used as traditional medicine for abdominal pain, rheumatic arthritis, and stroke. In a previous study, the ethanol extract of A. polygama Max. showed antiinflammatory activity in RAW 264.7 cells. In this study, we investigated the anti-inflammatory and anti-atherosclerosis effects of supercritical fluid marc extracts from A. polygama Max. Anti-inflammatory extracts were produced from supercritical fluid extraction of the silver vine under the following conditions; pressure, 1,500-4,500 psi, temperature $35-55^{\circ}C$ and extraction time 1-2 hr. To evaluate the anti-inflammatory and anti-atherosclerotic effects of the extracts, we studied nitric oxide (NO), prostaglandin $E_2$ ($PGE_2$), and tumor necrosis factor-alpha (TNF-$\alpha$) levels in RAW 264.7 cells and MMP-9 activity in human aortic smooth muscle cells (HASMC). The Marc 11 extract inhibited the production of NO, $PGE_2$, and TNF-$\alpha$ by lipopolysaccharide in RAW 264.7 cells. Moreover, the marc 11 extract inhibited TNF-$\alpha$-induced MMP-9 activity in HASMC. These results indicate that the Marc 11 extract of A. polygama Max. has the potential for use as an anti-atherosclerosis agent.

• Applied Chemistry for Engineering
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• v.8 no.5
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• pp.860-865
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• 1997

Brown rice oil contains palmitic acid, linolenic acid, linoleic acid, oleic acid, stearic acid, tocopherol, squalene, etc. The oil including essential fatty acids was extracted from the domestic brown rice bran using supercritical carbon dioxide(SCC) process, and the extracts were analyzed with GC-MSD. The extraction amount of brown rice oil was dependent upon the operating pressure and temperature, and the fatty acid composition of oil was varied with the reduced density(${\rho}_{\gamma}$) of the SCC. About 70~80% of brown rice oil was extracted in 4 hours. Especially, squalene which was not found in solvent extract phase was identified in supercritical fluid extraction phase only.

• KSBB Journal
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• v.11 no.1
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• pp.100-106
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• 1996

The extraction of taxol and baccatin III from the ground needles of Taxus cuspidata were carried out by using supercritical carbon dioxide with and without cosolvents such as ethylacetate and methanol at 300 bar and 313K. Taxol is a promising anticancer agent and baccatin III is a precursor of semisysthesis of taxol. The taxol and baccatin III contents in the extracts were determined by a HPLC. The highest yields of taxol and baccatin III could be obtained by the supercritical extraction with 3wt% methanol and ethylacetate, respectively, as cosolvents. It was also found that the selectivity of taxol and baccatin III were 0.117 and 1.245wt%, respectively, with 0.7wt% ethylacetate, which demonstrated that the selectivity of taxol and baccatin III were increased about 1.8 and 19 times than those of conventional organic solvent extraction.