• Applied Chemistry for Engineering
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• v.19 no.5
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• pp.484-490
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• 2008

Electrospun of PVP (polyvinylpyrrolidone) ultra fine fibers were fabricated using various solvents including methanol, ethanol, 2-propanol, butanol, acetone, methylene chloride, and DMF, which possess different properties such as boiling point, dielectric constant, and dipole moment. Electrospun PVP fiber was influenced by viscosity, conductivity, and surface tension of spinning solution. Therefore, the electrospun PVP fiber was successfully prepared under critical conditions of viscosity > $0.114kg/m{\cdot}s$, conductivity > 1.02 mS/m, surface tension < 30.0 mN/m. In case of an ethanol solvent system, average diameter of PVP fiber increased from 1701 nm to 5454 nm as increased the applied voltage from 10 kV to 20 kV.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.1
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• pp.28-32
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• 2023

We optimized ultrasound-assisted extraction to improve the extraction efficiency of bioactive compounds from the microalgae Acutodesmus reginae. To optimize this extraction process, we investigated the effects of solvent type, solvent concentration, extraction time, extraction number, and extraction power on the production of lutein, α-carotene, β-carotene, and chlorophylls a, and b. After sequential optimization of these main variables, the maximum amount of each compound was extracted at 30℃ with an ultrasound power of 80 W and using 99.5% methanol. Under these optimum conditions, the amount of lutein, α-carotene, β-carotene, and chlorophylls a, and b, were measured as 10.43, 8.66, 3.76, 15.43, and 6.39 mg/g dry matter respectively.

• Journal of Food Hygiene and Safety
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• v.14 no.4
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• pp.365-371
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• 1999

Microwave-assisted extraction (MAE) is known as a more environmental-friendly process with economic advantages in terms of less time, less solvent, less energy and less waste than the current reflux method that is time-consuming. MAE was applied to extract three pesticides (quintozene, tolclofos-methyl and procymidone) from ginseng in a pesticide residue analysis and eliminate pesticide contaminants from ginseng prior to production of the ginseng extracts. The optimal conditions for pesticide extraction from ginseng were 50% in power (150 watts), 2 minutes, 20 mL hexane and 2.0 g sample. The results of optimal conditions were compared with those of Soxhlet method (7 hours, 150 mL hexane). The recoveries between two methods were almost same while time and amount of solvent used in MAE were significantly decreased in comparing with those in the Soxhlet methods. When the 45% ethyl alcohol as a extraction solvent was applied to eliminate pesticides from ginseng prior to the production of the ginseng extracts, it was found that 100% quintozene, 69％ tolclofos-methyl and 83% procymidone were eliminated from ginseng. The data showed that MAE may be used to eliminate pesticide contaminants in ginseng prior to making the ginseng extracts.

• YAKHAK HOEJI
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• v.56 no.4
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• pp.240-247
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• 2012

Sabaek-san has been used for the treatment of inflammatory diseases derived from the cold with high fever, cough, and lung dysfunction in Korea and China. There is no study for the comparison between different solvent extracts of Sabaek-san. We made two samples, one is Sabaek-san water extract (SBSW) and the other is Sabaek-san 30% EtOH extract (SBSE). Both extracts inhibited inducible nitric oxide synthase(iNOS) protein, reduced iNOS-derived nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Also, they reduced tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) and interleukin-$1{\beta}$ (IL-$1{\beta}$) production. These anti-inflammatory effects caused by induction of heme oxygenase (HO)-1. HO-1 enzyme plays an important role of cellular anti-oxidant and anti-inflammatory systems. The induction of HO-1 is primarily regulated at the transcriptional level, and its induction by various inducers is related to the nuclear transcription factor-E2-related factor 2 (Nrf2). However, it is worth taking note that SBSE has more powerful anti-inflammatory effects than SBSW. In this study we suggest that different solvent extraction makes different therapeutic actions.

• Clean Technology
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• v.18 no.4
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• pp.347-354
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• 2012

In this study, simulation works have been performed for the $CO_2$ removal process contained in the DME production process using NMP (N-methyl-2-pyrrolidone) as a solvent. PRO/II with PROVISION release 9.1 at Invensys was used as a chemical process simulator and NRTL activity coefficient model with Henry's law option and Soave-Redlich-Kwong equation of state were used for thermodynamic models. For the determination of the binary interaction parameters in NRTL model, regression works have been performed to match the experimental thermodynamic data. Optimal feed tray location which minimizes the reboiler heat duty was determined.

• Journal of Life Science
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• v.12 no.4
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• pp.423-426
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• 2002

Enantioselective resolution of racemic para-nitrostyrene oxide was investigated using epoxide hydrolase activity of Aspergillus niger LK for the production of optically pure (S)-para-nitrostyrene oxide. To overcome the poor solubility of the substrate, enantioselective hydrolysis in an organic solvent was attempted under optimized reaction conditions including reaction temperature and water content. (S)-para-Nitrostyrene oxide with high optical purity (> 99% ee) was obtained at 37% yield using fungal epoxide hydrolase-catalyzed enantioselective resolution.

• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.3
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• pp.77-87
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• 2006

Micro- or nano-size particles are required to improve the combustion efficiency and stability in the case of solid explosives and propellants. The micro-structural properties of an energetic material strongly influence the combustion and explosion behavior. However, the traditional size reduction techniques, including milling, are not suitable for production of ultra-fine size particles. As an alternative to the traditional techniques, various re-crystallization processes based on supercritical fluids have recently been proposed. Supercritical fluids are fluids at temperatures and pressures above their critical point. In principle, they do not give problems of solvent contamination as they are completely released from the solute when the decompression occurs. Rapid Expansion Supercritical Solutions(RESS) and Supercritical Anti-Solvent Process(GAS/SAS) are representatives of a nano-size particle formation process of energetic materials using supercritical fluids. In this work, various fine particle formation processes using supercritical fluids are discussed and the results are presented.

• Journal of Forest and Environmental Science
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• v.36 no.1
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• pp.62-66
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• 2020

Ethanol fermentation of the enzymatic hydrolysates from the products pretreated using 1-ethyl-3-methyl-imidazolium acetate ([EMIM]Ac) and its co-solvents with dimethylformamide (DMF) was conducted using Saccharomyces cerevisiae (D452-2). The optical density change due to the yeast cell growth, the consumption amount of monosugars (glucose, xylose), the concentration of acetate, and ethanol production yield were investigated. The co-solvent system lowered inhibition of the growth of the cells. The highest concentration of glucose (7.8 g/L) and xylose (3.6 g/L) was obtained from the enzymatic hydrolysates of the pretreated product by pure [EMIM]Ac. The initial concentration of both monosugars in the enzymatic hydrolysates was decreased with increasing fermentation time. Ethanol of Approximately 3 g/L was produced from the enzymatic hydrolysates by pure [EMIM]Ac and co-solvent with less than 50% DMF.

• Transactions of the Korean hydrogen and new energy society
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• v.16 no.2
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• pp.159-169
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• 2005

Cellulose, consisted of 45 wt% in wood, is usable as fuels and heavy oil additives if depolymerized to monomer unit, because the chemical structures are similar to high octane materials found in gasoline. In this study, thermochemical degradation by solvolysis reaction of cellulose such as the effect of reaction temperature, reaction time and type of solvent on conversion yield and degradation products were investigated. It was found that the effectiveness of the solvent on the sovolysis reaction was as follows; acetone>n-butanol>tetralin. When acetone was used as a solvent, the highest cellulose conversion was observed to be 91.8% at 500$^{\circ}C$, 40min. Combustion heating value of liquid products from thermochemical conversion processes was in the range of 7,330${\sim}$7,410cal/g. The energy yield and mass yield in acetone-solvolysis of cellulose was as high as 66.8% and 37.0 g oil/100g raw material after 40min of reaction at 400$^{\circ}C$. Various aliphatic and aromatic compounds were detected in the cellulose solvolysis products. The major components of the solvolysis products, that could be used as fuel, were mesityl oxide, mesitylene, isophorone.

• Clean Technology
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• v.13 no.4
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• pp.274-280
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• 2007

A liquid-liquid solvent extraction process was developed in this study to recover Fe and Ni from heavily concentrated aqueous ferric chloride solution, in an effort to substitute the conventional iron reduction method. Solvent composition and extraction conditions were first developed from the laboratory experiments, and the pilot system was designed and built for commercialization. Stage numbers for extraction and stripping were determined from pilot plant runs, and other operation data were obtained for mass production.