• Proceedings of the Membrane Society of Korea Conference
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• 1995.04a
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• pp.45-45
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• 1995

Filtration, one of the most important process in the various industrials, is defined as the separation of two or more compounds from a fluid by passing the mixture refers to the separation of solid, immisible particles from liquid or gaseous mixture. Membrane filtration which is a type of filtration extends it's application further to include the separation, concentration, and filtration. The main objective of this investigation is the preparation of organic solvents-resistant polyimide membranes by using phase inversion technique and their application as a UF membrane. Specially, the dope solution was prepared from the newly developed method. The newly developed method is that the dope solution was directly prepared from the polyimide solution which was prepared by the modified one-step polymerization. The effects of the parameters for membrane preparation such as the casting solution composition and the casting conditions were investigated and the performance and chemical stabfiity of membrane are going to be tested.

• Journal of the Korean Chemical Society
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• v.6 no.1
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• pp.64-68
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• 1962

The graft polymerization of styrene to polyvinyl alcohol using a photosensitizer(benzophenone) and ultraviolet light was studied. Styrene was grafted onto polyvinyl alcohol up to when polyvinyl alcohol was pre-immersed in water and irradiated by ultraviolet light for 24 hours styrene solution of benzophenone(0.01 molarity). The highest percentage of graft obtained in the grafting which was proceeded in the presence of water added immediately before irradiation was 29%. The grafting was proportional to irradiation time within a certain limit of time, i.e., 24 hours, and presumably was initiated at the surface. After a certain degree of grafting a definite maximum was reached. Graft polymer prepared in this experiment showed high resistance to various solvents.

• Bulletin of the Korean Chemical Society
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• v.32 no.3
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• pp.1037-1040
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• 2011

The dinuclear complex 1 with cooperative hydrogen bonds can be prepared by the metal-directed reaction of Eq. (2). This work shows that the coordinated hydroxyl group trans to the secondary amino group is deprotonated more readily than that trans to the tertiary amino group and acts as the hydrogen-bond accepter. The lattice water molecules in 1 act as bridges between the two mononuclear units through hydrogen bonds. The complex is quite stable as the dimeric form even in various polar solvents. The complex exhibits a weak antiferromagnetic interaction between the metal ions in spite of relatively long Cu$\cdots$Cu distance. This strongly supports the suggestion that the antiferromagnetic behavior is closely related to the cooperative hydrogen bonds.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.381-382
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• 2008

$TiO_2$ colloidal solution was electrosprayed for preparing a conductive thin film with high quality. Electrospray is a technique of liquid dispersion electrically and a good method of manufacturing nanoparticle, nanofiber, porous membrane, film preparation and coating. Water and ethanol were used as solvents and their mixing ratio was varied for studying the influence of solvent volatile on nanoparticle dispersion. Various nozzles to control the thru-put of solutions.were examined. Integrated analytical method and scanning electron microscope were used to analyze integrity and microscopic images.

• Bulletin of the Korean Chemical Society
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• v.31 no.4
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• pp.850-858
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• 2010

The electronic absorption spectra of five Schiff bases derived from 2-hydroxy-1-naphthaldehyde with glycine, alanine, leucine, valine and phenylalanine have been measured in various solvents. The observed bands were assigned to the proper electronic transitions and compared with the predicted transitions at the semiempirical level of theory. The calculated equilibrium constants are in agreement with the experimental results, predicting the existence of all studied compounds predominantly or completely in keto-imine tautomerism. On the other hand, a correlation between $\nu\;(cm^{-1})$ (main frequency of each compound) and the well known solvent parameters $E_T$ (30), $\varepsilon_T$, $\pi^*$ been made. Furthermore, the acid dissociation constants, $pK_a$, were determined by using three different spectrophotometric methods.

• YAKHAK HOEJI
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• v.25 no.4
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• pp.193-197
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• 1981

Germanium (Ge) content in Zingiberis Rhizoma was determined by flameless atomic absorption spectrometry with a graphite tube atomizer. The Ge content of the cortical layer was 65.mu.g/g, the central cylinder, $98\mu$g/g and the total, $87\mu$g/g. In the effect of the extraction of Ge by various solvents, polar solvent was more effective than the nonpolar one, Especially, water was the most effective solvent. The water extract of Zingiberis Rhizoma, separated by sephadex G-25 gel filtration, was fractionated into 2 peaks at 254nm. Both the peaks showed atomic absorptions of Ge. It may be concluded that the Ge components of Zingiberis Rbizoma exist as the form of an aqueous organic compounds or associated forms with proteins.

• Bulletin of the Korean Chemical Society
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• v.30 no.4
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• pp.825-828
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• 2009

Alum $(KAl(SO_4)_2{\cdot}12H_2O)$ is an inexpensive, efficient, non‐toxic and mild catalyst for the synthesis of bis(indolyl)methanes by the reaction of 1H-indole with various aldehydes/ketones under the influence of ultrasound irradiation in solvent‐free condition. The remarkable advantages of this method are the simple experimental procedures, shorter reaction times, high yields of product and green aspects by avoiding toxic catalysts and solvents.

• Clean Technology
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• v.24 no.1
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• pp.15-20
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• 2018

Hexafluoropropyleneoxide ($C_3F_6O$, HFPO) is highly expensive and it may be used as a raw material for the synthesis of various fluorine based compounds. Currently, extractive distillation method has gained considerable attention to collect the HFPO from a mixture of HFPO / hexafluoropropylene ($C_3F_6$, HFP). Optimized operating conditions are studied using a theoretical method for the extraction process. Among available solvents for the purification process, the use of 1,1-dichloro-1-fluoroethane exhibits a high purity of HFPO as a top product and minimize the required heat duty. Since the boiling point of the solvent increases as the pressure in the column increases, the enhanced extractive capability of the solvent led to the high purity of HFPO at the high pressure.

• Archives of Pharmacal Research
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• v.28 no.4
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• pp.382-390
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• 2005

chial allylic ethers with a hydroxyl group attached to the $\pi-system$ and chlorosulfonyl isocyanate. The enantioselectivity of the CSI reaction with the chiral allylic and benzylic ethers was examined in various solvents and temperatures. Based on these results, it was proposed that the CSI reaction is a competitive reaction of a $S_{N}i$ (retention) and a $S_{N}1$ mechanism (racemization) according to the stability of the carbocation intermediate. This means that there is a greater proportion of retention with the less stable the carbocation intermediate and vise versa.

• KSBB Journal
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• v.19 no.6 s.89
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• pp.421-426
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• 2004

The extraction and separation of isoflavones from Korean soybean were peformed by various mechanical and chemical extraction methods. They included solvent extraction, stirring, supersonification and sub/supercritical water extraction. From the experimental results of the variation of solvent extraction by change in composition, the increase in extraction of a specific compound by stirring or supersonic energy, and the application of supercritical fluid with superior solvating power over solvents, the sonification was the most desirable extraction method in extracting aglycone isoflavones, daidzein and genistein from Korean soybean.