• Journal of Pharmaceutical Investigation
• /
• v.5 no.4
• /
• pp.17-23
• /
• 1975

복용량이 비교적 적고, 난용성 의약품(醫藥品)으로 antirheumatism에 사용되고 있는 phenylbutazone을 macromolecule polymer로서 water soluble carrier인 polyvinylpyrrolidone과 solvent method로 1:1, 1:5, 및 1:9(w/w)의 coprecipitate를 형성(形成)시켰으며, 이들 coprecipitate의 용출 속도를 Pure drug 및 coprecipitate 형성 용매인methanol에서 재결정한 recrystallized pure drug의 그것과 측정 비교(比較)하였다. 1:1,1:5 및 1:9(w/w)의 coprecipitate는 recrystallized pure phenylbutazone보다 약 4.5배의 용출의 증가를 보였고, 이들 1:1,1:5,1:9(w/w)에서의 그 carrier의 양(量)에 따른 용출에의 영향은 거의 없었다. 시간(時間)에 대(對)한 log probit를 plot하여 구(求)한 dissolution half life, $T_{50%}$는 coprecipitate ratio 1:1(w/w)에서는 5.5분, 1:5에서는 10분, 1:9에서는 12.5분이었다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 1996.11a
• /
• pp.122-127
• /
• 1996

본 실험은 미국 Washington 주 V 도시에서 1987년과 1908년에 PCP 유출사고로 발생된 PCP 오염토양을 처리하는 연구로 heme과 과산화수소를 이용한 abiotic 기술로 14C-PCP를 이용하여 PCP의 거동조사로 물질수지 연구와 pan 연구를 통하여 오염토양에서 PCP 제거되는 분해능을 조사하였다. $^{14}$ C-PCP를 이용한 오염토양에서 물질수지는 2g 오염토양당 0.035 g heme과 0.11g 과산화수소를 첨가하여 반응 24시간 동안 반응시킨후 완전 산화율은 20%, 토양잔류 27%, 그리고 용매상에는 38%로 총 $^{14}$ C-PCP가 회수율은 85% 이었다. PCP 유출사고로 보관된 오염토양 처리를 위한 pan 연구결과 24시간내 초기 PCP 987 mg/kg soil에서 85%가 제거되고, 서서히 분해되어 33일 에는 95% 분해능을 보여주고 있다.

• Journal of the Korean Chemical Society
• /
• v.19 no.2
• /
• pp.123-129
• /
• 1975

The rate constants of the hydrolysis of phenylvinylsulfone were determined by ultraviolet spectrophotometry at various pH and a rate equation which can be applied over wide pH range was obtained. The reaction mechanism of hydrolysis of phenylvinylsulfone and especially the catalytic contribution of hydroxide ion which did not study carefully before in acidic media, can be fully explained by the rate equation obtained. The rate equation reveals that: below pH 7, the reaction is initiated by the addition of water molecule to phenylvinylsulfone. At above pH 9, the overall rate constant is only dependent upon the concentration of hydroxide ion.

• Journal of the Korean Vacuum Society
• /
• v.22 no.3
• /
• pp.138-143
• /
• 2013

Recently, ZnO nanoparticles have been studied in various application fields due to their physico-chemical properties. In this study, we have researched on the ZnO photocatalytic activity by redox reaction. ZnO nanoparticles have low photocatalytic activity in comparison with $TiO_2$ nanoparticles because it has the disadvantage that the formation of $Zn(OH)_2$ in water solvent. Therefore, we were synthesized ZnO nanoparticles by spray-pyrolysis method, and then studied on stability in water solvent. At the results, the water treated-ZnO nanoparticles showed higher photocatalytic activity than non-treated ZnO nanoparticles because molecular $H_2O$ was increased onto the ZnO surface under the water treatment. Also, we confirmed that the ZnO nanoparticles synthesized by spray-pyrolysis method is very stable in the water solvent.

• Journal of Life Science
• /
• v.21 no.5
• /
• pp.700-705
• /
• 2011

Using enrichment procedures, we isolated organic solvent-tolerant Bacillus sp. BCNU 5005 from waste water and soil in the Ulsan industrial plant region. BCNU 5005 had a maximum similarity of 98% with B. subtilis and was designated as B. subtilis based on phylogenetic analyses using 16S rDNA sequences. Generally, most bacteria and their enzymes are destroyed or inactivated in the presence of high concentrations of organic solvents. However, the lipase activity of B. subtilis BCNU 5005 was very stable in the presence of various kinds of solvents (25%, v/v) except chloroform, ethylbenzene and decane. Furthermore, BCNU 5005 was determined to have a degradative ability towards organic solvents. This organic solvent tolerant Bacillus sp. BCNU 5005 could be used as a new potential resource for biotransformation and bioremediation.

• Journal of the Korean Chemical Society
• /
• v.31 no.3
• /
• pp.250-257
• /
• 1987

The electrical conductances for the thorium (IV) complexes with crown ethers have been measured in DMSO, and water solvents, and the oxidation-reduction reaction mechanisms, electron number and diffusion coefficients in the reversible reduction process have been examined by polarography and cyclic voltammography. The dissociation mole ratio of $Th^{4+}$ and nitrate ion are 1:1 and in aprotic solvent, and 1:4 in protic solvent like as water. The limiting molar conductances of all complexes in aprotic solvent have been found to be in the range of $92.2{\times}159$ $ohm^{-1}cm^2mol^{-1}$. In aprotic solvent, DMSO, the reduction of each complex is reversible by one electron reduction of one step, and the range of diffusion coefficients is obserbed to be $5.83\;10^{-6}{\sim}6.90{\times}10^{-6}$. The complexes which have reduction step were hydrolyzed above at 1.8volt with reference saturated calomel electrode, generating the hydrogen gas. The reaction mechanisms of thorium (IV)-crown ether complexes appear as follows. ${Th_m(IV)L_n(H_2O)_x(NO_3)_{4y}}_=^{DMSO} {\overline{{Th_m(IV)L_n(H_2O)_x(NO_3)_{4y-1}}}^+ + NO_3-$

• Applied Chemistry for Engineering
• /
• v.8 no.4
• /
• pp.694-699
• /
• 1997

Normal-phase HPLC was used to separate the useful phospholipids, PE, PI and PC in soybean lecithin. The mobile phase used in this experiments were haxane, isopropanol and methanol, the gradient mode was applied as the three components could not be separated by the isocratic mode. To find the optimum separation condition, the concentration profiles of effluents were calculated from the plate theory and the capacity factor in step-gradient mode. From the calculated results, PE was separated with hexane/isopropanol/methanol = 90/5/5vol.% in isocratic mode and PI and PC were resolved in the conditions of 10min gradient time and the second mobile phase of hexane/isopropanol/methanol=50/20/30vol.% in step-gradient mode. The agreement between the calculated concentration profile and experimental data was good, so the methodology developed in this work can be used to obtain the optimum separation condition in gradient mode.

• KSBB Journal
• /
• v.18 no.5
• /
• pp.347-351
• /
• 2003

The extraction of glycyrrhizic acid from licorice using supercritical carbon dioxide (SCCO$_2$) was investigated with respect to the effects of extraction parameters such as the kind and amount of modifier, temperature, pressure, and extraction time. The conventional organic solvent extraction was also conducted for a quantitative comparison. The content of glycyrrhizic acid in crude extracts was analyzed by HPLC and the yield of glycyrrhizic acid was computed as a weight percent recovery. The optimal pressure and temperature for SCCO$_2$ extraction were found to be 40 MPa and 80$^{\circ}C$, respectively, when SCCO$_2$ was modified with 70% aqueous ethanol. Under the same pressure and temperature, the highest recovery was attained to be 104.57% in the first 60 min when the concentration of 60%, aqueous ethanol in SCCO$_2$ was 15%.

• Journal of the Korean Chemical Society
• /
• v.31 no.3
• /
• pp.258-270
• /
• 1987

A series of new thorium nitrate complexes with crown ethers have been synthesized from the reaction of the hydrated thorium nitrate, with the appropriate crown ethers of different cavity sizes in various solvents such as methanol, ethanol, butanol, methylacetate, acetone, tetrahydrofuran and acetylacetone. CHN elemental analysis, ICPAS, thermal analysis and Karl-Fischer method have been used to characterize their compositions, and the spectroscopic methods of IR, UV, $^1H-NMR$, and X-ray diffraction have been employed to determine the structures and solvolysis phenomena of these complexes. and the electrical conductances were measured in DMSO, and water solvent. The solvolysis have been observed only in the complexes synthesized in acetylacetone solvent. In the solvated complexes of 15-crown-5 and 18-crown-6, the mole ratio of $Th^{4+}$: ligand : acetylacetone is found to be 1:1:1, but in the non-solvated complexes of 12-crown-4 and 15-crown-5, the mole ratios of Th:L are 1:2 and 2:3, respectively, and that in the complexes of both 18-crown-6 and dicyclohexano-18-crown-6 is 1:1. All complexes which were not solvated have shown $n{\to}{\sigma}^{\ast}$ electronic transitions of crown ether whereas complexes solvated have exhibited both $n{\to}{\sigma}^{\ast}$ of crown ether and $n{\to}{\pi}^{\ast}$ transitions of acac. The dissociation mole ratio of $Th^{4+}$ and nitrate ion is found to be 1:1 in aprotic solvent, and 1:4 in protic solvent like water.

• The Korean Journal of Pesticide Science
• /
• v.3 no.2
• /
• pp.8-18
• /
• 1999

The degradation of a fungicide, $^{14}C$-propiconazole, in sterile and nonsterile soil from different depths was investigated. $^{14}C$-propiconazole plus propiconazole standard was treated on the soil at the rate of 7.55 mg/kg and the soil was incubated at $25^{\circ}C$ for 20 weeks. The amounts of $^{14}CO_{2}$ solvent extractable and non-extractable $^{14}C$, and degradation products of $^{14}C$-propiconazole were investigated during incubation time. The relative amounts of $^{14}CO_{2}$ released in the sterile and nonsterile soils were ranging from 0.7 to 1.3% and from 4.8 to 7.6% of applied $^{14}C$, repectively. The amounts of solvent non-extractable residues in the sterile and nonsterile soils were ranging from 11.2 to 22.1% and from 22.2 to 41.9% of of applied $^{14}C$, repectively. The amounts of solvent non-extractable residues were increased with incubation time and most of $^{14}C$ were detected in the humin fraction. The hydroxylated and ketone compound were confirmed as a degradation products of propiconazole by GC/MS analysis, whereas parent compound was detected in sterile soil, which suggested that propiconazole was not degraded biologically under the sterile soil. From the results of volatilization, mineralization and degradation of propiconazole, propiconazole was stable chemically and bilogically in soil.