• KSBB Journal
• /
• 제9권3호
• /
• pp.312-318
• /
• 1994

Ac-Tyr-OH의 에스테르화 반응은 water/water­m miscible organic solvent를 이용하여 단일상계 (one phase system) 조건 하에서 ${\alpha}$-chymotrypsin의 촉 매작용으로 진행하였으며, 그 결과는 다음과 같다. Ac- Tyr-OH(1OmM)이 함유된 에탄올(lOml)[ 4 % %(v/v) buffer 함유] 용액에서 ${\alpha}$-chymotrypsin의 촉매작용에 의한 에스테르화 반응에 영향을 마치는 흡착물질 chitin, chitosan, Sephadex G-25 및 G-50, CM 및 DEAE-Sephadex, CM 및 DEAE cellulose 중 chitin을 첨가하였을 경우, 에스테르화 수율이 62%로 가장 높았다. 그리고 에스테르화 수 율에 마치는 최적반응조건은 chitin/${\alpha}$-chymotry psm의 비가 20(w/w), 온도 $35^{\circ}C$, pH 8.0 빛 유기 용매에 첨가된 수용액의 농도는 2%(v/v)였다. 또한, water/water-miscible organic solvent system 에서 chitin의 첨가는 효소의 안정성에 기여하는 것으로 나타났다. 최적반응조건 하에서 에스테르화 반응의 수율, Km 및 Vmax 값은 각각 93%, 3.093mM 및 1.088mM/mg/hr이었다.

• Elastomers and Composites
• /
• 제29권3호
• /
• pp.226-233
• /
• 1994

The properties of the mixed prepolymer-urethane in the range of 10-40 phr were observed. LBR and LCR have same functional group but different in structure of molecular. The viscosity of mixture depending on content of rubber, adhesive strength, thermal property and compatibility with a diluted solvent are as follows: 1. The viscosity of the mixture was influenced by solubility of the diluent for urethane resin and liquid rubber. 2. Adhesive strength showed the highest value at 30phr rubber, decreased gradually at above 30phr rubber. And LBR revealed better physical property than that of LCR. 3. The most effective factors affecting adhesive strength are molecular structure of rubber, the type of solvent, and volatility. 4. Urethane resin containing LBR showed better compatibility for solvent and faster drying velocity. 5. LBR showed more favorable compatibility and dispersion state than those of LCR by analyzing the results of SEM.

• Bulletin of the Korean Chemical Society
• /
• 제32권5호
• /
• pp.1543-1546
• /
• 2011

N-Bromosaccharin/$Mg(ClO_4)_2$ is an effective and regioselective system for ${\alpha}$-monobromination of 1,3-dicarbonyl compounds. A wide variety of ${\beta}$-keto esters and 1,3-diketones in reaction with this system afforded a regioselectively ${\alpha}$-monobrominated products. The bromination reaction can be conducted at 0-5 $^{\circ}C$ either in solution or under solvent-free conditions.

• 한국환경과학회지
• /
• 제10권5호
• /
• pp.381-386
• /
• 2001

The characteristics of precipitation separation and solvent extraction separation of magnesium from the waste bittern were studied experimentally In the result of precipitation separation, the size of magnesium hydroxide precipitated was not affected on pH, but decreased with increasing the precipitation temperature. The purity of magnesium oxide precipitated was increased with pH beyond pH 11. From the solvent extraction separation, the equilibrium extraction ratio of magnesium was increased with pH and temperature of extraction phase, the concentration of stripping phase, and with decreasing pH of stripping phase. The extractant of Aliquat 336 and Acid 810 mixture was more effective than that of DCH18C6 and $D_2EHPA$ mixture in the extraction separation of magnesium.

• Bulletin of the Korean Chemical Society
• /
• 제19권1호
• /
• pp.50-56
• /
• 1998

A solvent sublation was studied for the determination of trace Cd, Co, Cu and Ni in water samples. Ammonium pyrrolidine dithiocarbamate (APDC) was used as a complexing agent. Experimental conditions such as pH of solution, amounts of APDC, the type and amount of surfactant, the type of solvent, etc. were optimized for the effective sublation of analytes. After metal-PDC complexes were formed in sample solutions of pH 2.5, the precipitate-type complexes were floated in a flotation cell with an aid of sodium lauryl sulfate as a surfactant and by bubbling with nitrogen gas. The precipitates were dissolved and separated into the surface layer of methyl iso-butyl ketone (MIBK). The analytes preconcentrated were determined by a graphite furnace atomic absorption spectrophotometry (GF-AAS). Extractability of each element was 88% for Cd(Ⅱ), 86% for Co(Ⅱ), 95% for Cu(Ⅱ) and 76% for Ni(Ⅱ), respectively. And this procedure was applied to the analysis of real samples. From the recoveries of more than 92%, it was concluded that this method could be simple and applicable for the determination of trace elements in various water samples of a large volume.

• Bulletin of the Korean Chemical Society
• /
• 제17권6호
• /
• pp.506-510
• /
• 1996

The syntheses and photoreactions of haloarenes, in which the aryl and haloaryl moieties are tethered by a simple alkyl group, were studied. For 2-benzyl-1-halobenzene, in which two aryl moieties were connected by methylene group, photoreduced product, diphenylmethane, was obtained along with the minor formation of the photocyclized product, fluorene, in acetonitrile solvent. For 1-halo-2-phenethylbenzene, in which two aryl moieties were connected by ethylene group, photocyclized products, 9,10-dihydrophenanthrene and phenanthrene, were obtained along with the minor formation of photoreduced product, bibenzyl, in acetonitrile solvent. The photoreaction selectivities in several solvent systems were studied: In cyclohexane, 2-benzyl-1-chlorobenzene was photoreduced more effective than 2-benzyl-1-bromobenzene; In the presence of NaOH, 1-halo-2-phenethylbenzenes gave 9,10-dihydrophenanthrene and, in the presence of toluene, they gave phenanthrene. A radical reaction mechanism is proposed for the explanation of the reactions. This study shows that the photoreaction of haloarene, in which haloaryl and aryl moieties are tethered by ethylene group, can be used for ring formation of 9,10-dihydrophenanthrene otherwise difficultly accessible.

• 공업화학
• /
• 제24권1호
• /
• pp.82-86
• /
• 2013

기능성 용매인 1-buthyl-3-methylimidazolium trifluoromethanesulfonate ([Bmim][$CF_3SO_3$])를 이용하여 팔라듐 입자를 제조하였다. 제조된 입자의 형상은 기능성용매의 농도에 영향을 받았다. 또한 hexafluoropropylene 수소화 반응용 촉매를 제조하기 위하여 탄소 담지 팔라듐 입자를 제조하였다. 촉매 제조 시 기능성용매의 농도와 소성온도를 변화해 가면서 최적의 촉매제조 조건을 구하고자 하였다. 수소화 촉매의 반응활성의 상기의 두 가지 제조조건에 따라서 크게 달라지는 것이 관찰되었다. 동일한 반응조건에서 기능성용매와 팔라듐 전구체의 몰 비가 동일하고 소성온도가 $500^{\circ}C$에서 제조된 촉매가 가장 우수한 반응성을 보였다.

• 한국식품영양학회지
• /
• 제28권1호
• /
• pp.1-8
• /
• 2015

This study was designed to determine the antioxidant activity of solvent fractions of broccoli sprouts grown by controlling the growing environment at the plant factory system. Fractionation was achieved with chloroform, n-hexane, ethyl acetate, butanol, water by 70% EtOH extract of the broccoli sprouts. Each solvent fraction was put through TLC and HPLC to separate active components. Higher antioxidant activities were observed for the butanol and ethyl acetate layers. Further evaluation of each of the 5 layers (LH1 to LH5) of the butanol fraction showed that the refined LH3 extract had a high antioxidant effect. Components with similar Rf values from TLC had the same retention times and peaks in the HPLC analysis. It was also determined that the sulforaphane content was high at the chloroform and butanol layers and the sulforaphane was responsible for, the high antioxidant activity. Thus, to use for functional materials, the butanol extract/layer of broccoli sprouts is recommended as the most effective.

• Journal of Microbiology
• /
• 제38권3호
• /
• pp.187-191
• /
• 2000

A validation study was conducted to determine the efficacy of solvent/Detergent (S/D) inactivation and Q-Sepharose column chromatographic removal of the human immunodeficiency virus (HIV) during the manufacturing of a high purity antihemopilic factor VIII (GreenMono) from human plasma. S/D treatment using the organic solvent, tri (n-butyl) phosphate, and the detergent, Trition X-100, was a robust and effective step in eliminating HIV-1. The HIV-1 titer was reduced from an initial titer of 8.3 log10 TCID50 to undetectable levels within one minute of S/D treatment, HIV-1 was effectively partitioned form factor VIII during Q-Sepharose column chromatography with the log reduction factor of 4.1 . These results strongly assure the safety of GreenMono From HIV.

• 한국식품영양과학회지
• /
• 제27권3호
• /
• pp.406-412
• /
• 1998

Such extraction conditions as the kinds of solvent, extracting temperature, extracting time, ratio of material to solvent and particle size of material, were studied to maximize the extraction of oleoresin from chipi. Larger amount of soluble solids were extracted from seeds with nonpolar solvents (hexane, pentane, ether) for extraction, because the seeds contained large amount of crude fats and monoterpene(limonene) volatile compounds. Larger amount of soluble solids were extracted from peel with polar solvents(methanol, ethanol) of extraction because of large amount of water soluble colors, sugars and oxygenated terpene bolatile compounds in the peel. The application of the solvents in intermediate polarity (dichloromethane, acetone) resulted in more effective extraction of soluble solid and volatile compounds. Expecially, dichloromethane was an excellent solvent in extraction of volatile compounds. In the concern of volatile compound recovery yield, the optimum extraction conditions, such as temperature, time, mixing ratio of material to dichloromethane and mean particle size, were $25^{\circ}C$, 10min, 1:10(w/v), 355~250${\mu}{\textrm}{m}$ for chopi peels and 3$0^{\circ}C$, 10min, 1:8(w/v), 355~250${\mu}{\textrm}{m}$ for chopi seeds, respectively.