• Membrane Journal
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• v.32 no.1
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• pp.50-56
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• 2022

In this work, the solvent permeation and separation performance of organic solvent nanofiltration (OSN) membranes were evaluated. Particularly, the PuraMem (PM) series developed for nonpolar solvents were analyzed and tested in dead-end filtration system. PM membranes exhibited higher permeance for nonpolar solvents compared to polar solvents, and their rejection data did not follow conventional trends with respect to solute size. The data showed that simple solution-diffusion model is not suitable to describe the OSN membrane behavior, and a better solvent-solute-membrane interaction parameter must be developed.

• Applied Chemistry for Engineering
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• v.20 no.6
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• pp.685-691
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• 2009

Dispersions of fumed silica are made in 6 kinds of mono-solvents and mixed solvents which have hydroxyl group, non hydroxyl group, different polarity, and different molecular size. The viscosity and rheology behaviors of the each dispersion are investigated according to the viewpoint of solvent characteristic. The silica dispersion in polar solvent with hydroxyl group is stable and low viscous sol. The silica dispersion in non-polar solvent with non-hydroxyl group is high viscous gel. When the solvent with hydroxyl group is added to the silica dispersions with non-polar solvents, they show the reduction of viscosity with solvent content. They have minimum critical content which shows no viscosity change. The minimum critical solvent content is decreased according to the polarity of solvents with no hydroxyl group. The solvation layer which is formed on the silica surface through hydrogen bonding between hydroxyl-containing solvent and the silanol group of silica surface is the reason of stable and low viscous sol. In case of non-polar solvent, silanol on adjacent silica particles interacted directly by hydrogen bonding show high viscous and flocculated gel.

• Membrane Journal
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• v.33 no.6
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• pp.409-415
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• 2023

Apart from developing better membranes, a clever reconfiguration of membrane cascade process can improve the solute selectivity and minimize solvent consumption. In this work, solvent resistant cellulose nanofiltration membranes were fabricated and the solute rejection performance in various organic solvents were tested. Interestingly, cellulose membranes exhibited unique negative rejection profile in non-polar solvents. Such trend could be exploited to yield reverse selectivity, which showed that low molecular weight solute could be concentrated in the retentate. It was found that more than 3-fold solvent saving could be achieved at the same final purity.

• Journal of the Korean Chemical Society
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• v.40 no.6
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• pp.415-419
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• 1996

Hydrogen bonding, dielectric effects and steric effects are all factors which determine the carbonyl stretching frequency, νC=O of ketones in solution. The νC=O frequency of ketones is affected by change in concentration of ketones in various solvents. The νC=O frequency shifts to lower frequency in nonpolar solvents and shifts to higher frequency in polar solvents with the increasing volume% of ketones. In acetonitrle, the νC=O frequency shifts to higher frequency as the volume% of ketones is increased except dimethyl ketone. The νC=O frequency shifts to lower frequency as the solvent system becomes increasingly polar or with the increasing extent of intermolecular hydrogen bonding, as in the case of increasing volume% chloroform in $CHCl_3$/$CCl_4$ solvent system.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.9-12
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• 2003

요오드 2분자가 양이온(I$^{+}$)과 음이온(I$_3$$^{-}$)로 해리되어 이 매 생성된 양이온에 의한 비닐 에테르류의 양이온 중합에 관한 연구는 보고된 바 있으나$^{1)}$ 요오드를 개시제로 사용한 삼차부틸 에테르의 양이온 중합에 관한 결과가 발표된 것은 별로 눈에 뜨이지 않는다. 삼차 부틸 에테르는 단량체의 활성이 크고 중합거동이 타 비닐 에테르류와 매우 다르기 때문에$^{3),4)}$ boron trifluoride diethyl etherate를 개시제로 하고, n-햅탄 이나 톨루엔과 같은 비극성용매를 사용하여 저온에서 중합을 행한 결과만이 보고되고 있다.$^{2)-5)}$ (중략)

• Journal of Life Science
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• v.15 no.6 s.73
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• pp.948-954
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• 2005

In this study, we investigated antimicrobial and cytotoxicity effects to each fraction extracted from Solanum lyratum (SL), which were extracted methanol (SLM) and then the extract was fractionated into five different types : hexane (SLMH), ethyl ether (SLMEE), ethylacetate (SLMEA), butanol (SLMB) and aqueous (SLMA). The antimicrobial activity was analyzed by the paper disc method. Among the various solvent fractions, SLMEA showed the strongest antimicrobial activies. The cytotoxicity of SL fractions on HeLa, MCF-7, HT-29 and HepG2 cells was evaluated by MTT assay. Among various partition layers, SLMEE showed the strongest cytotoxic effects to all cancer cell lines. We also observed that quinone reductase (QR) was induced by all fraction layers of SL to HepG2 cells. Since the QR-induced effects of SLMEE on HepG2 cells at $160{\mu}g/ml$ concentration showed 2.1 when compared with a control value of 1.0, inducer of QR for cancer protection may be contained in this fraction.

• Journal of the Korean Chemical Society
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• v.42 no.1
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• pp.22-27
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• 1998

Fluorescence quenching of coumarin 153 and coumarin 481 with N,N-dimethylaniline in various solvents was investigated. Quenching rate constants are related to diffusion-limited rate constants to some extent. It is noted that smaller discrepancy was observed between the diffusion-limited rate constant and the experimental quenching rate constant when the stick boundary condition rather than the slip boundary condition was applied for estimating the diffusion coefficients. In nonpolar solvent like cyclohexane fluorescence quenching is adequately explained by the diffusion controlled process within the experimental error, but in acetonitrile the quenching rate constant was estimated to be consistently smaller than the diffusion limited rate constant. This may suggest that fluorescence quenching of coumarin dyes be affected not only by the molecular diffusion but also by the intramoleccular process such as charge separation.

• Analytical Science and Technology
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• v.13 no.4
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• pp.511-519
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• 2000

Water in the supercritical state ($T{\geq}374^{\circ}C$, $p{\geq}221$ atm) is a good solvent for nonorganic pollutants, but it is extremely corrosive. Subcritical Water Extraction (SWE) is a very fast and an efficient method to extract nonpolar environmental pollutants adsorbed on the sediments and soils. Many nonpolar organic compounds are sufficiently soluble to be extracted to the water under subcritical conditions. Complete extraction of PCBs from the sediments and soils takes only a few minutes by applying SWE with the subcritical water at 50 atm and at $260^{\circ}C$.

• Journal of the Korean Applied Science and Technology
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• v.32 no.2
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• pp.290-295
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• 2015

The purpose of this study is to separate nitrocellulose from 175 mm ammunition propellant by environmentally responsible recovery method. Recovery of nitrocellulose from obsolete ammunition is much more desirable than destruction since it can be reused in the several purpose. In spite of durable demilitarization of obsolete ammunition, the current holding amount of obsolete ammunition is gradually increasing and accumulated. The existing demilitarization methods, such as incineration and priming are strictly restricted for the noise, dust, oscillation and air and soil pollution. This study is focused on the separation of nitrocellulose by environmentally responsible recovery method by the solubility difference of nitrocellulose in nonpolar solvent. The purity of an extracted nitrocellulose was analysed by IR and TLC method and was clarified as very high.

• 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.