• Korean Chemical Engineering Research
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• v.58 no.1
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• pp.92-97
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• 2020

In this study, the solubilities of a pharmaceutical compound, nifedipine, in three mixed solvents were determined. In addition, the nifedipine, that was dissolved in solvents (acetone, DMF, methylene chloride), was recrystallized using antisolvents (water, hexane, carbon dioxide) The external shape, size, and melting point of the crystallized nifedipine were measured. As the mixed solvents, acetone+water, DMF+water, and methylene chloride+hexane were used, and the solubility of nifedipine decreased with increasing antisolvent concentrations in the mixtures. In case of acetone+water, the solubility maximum was observed due to the density anomaly of the mixture, and this phenomenon was not observed in other systems. The crystallized nifedipine particles exhibited the bladed, equant, and prismatic habits, and the particles size was significantly reduced compared to the raw material. The average particle size of raw nifedipine was 337 ㎛, and the size of crystallized particles was in the range of 11.6~69.8 ㎛. All the crystallized nifedipine particles had the same thermal behavior and this result was not influenced by the change of solvent and antisolvent.

• Journal of the Korean Chemical Society
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• v.35 no.1
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• pp.3-15
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• 1991

The gaseous mixtures of iso-propanol of 10 torr with carbon dioxide of 0∼1990 torr were irradiated with Co-60 gamma radiation up to 50 kGy, and the products such as carbon monoxide, acetone, methane, ethane, C$_3$H$_a$, C$_4$H$_b$ and tert-butanol were analyzed by gas chromatography. G(CO) value of 4 was obtained from the gas mixtures containing more than 490 torr of carbon dioxide. The production rates of the organic products and the decomposition rate of iso-propanol increased linearly with the pressure of carbon dioxide, and G(-iso-Propanol) and G(Acetone) values increased by 4 and 2, respectively, with each 10 torr increment of carbon dioxide pressure. The mechanisms of the radiolytic decomposition of iso-propanol and the production of carbon monoxide and organic materials are discussed on the basis of the experimental results of the present study.

• Journal of the Korean Chemical Society
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• v.30 no.4
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• pp.345-351
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• 1986

Monoxo-bridged binuclear molybdenum(V) complex, $[Mo_2O_3\;(bipy)_2\;(NCS)_4]$ in aqueous acetone mixture produces the corresponding dioxo-bridged binuclear molybdenum(V) complex, $MoO_4(bipy)_2(NCS)_2$. The rate of conversion of $[Mo_2O_3(bipy)_2(NCS)_4]$ to $MoO_4(bipy)_2(NCS)_2$ has been measured by spectrophotometric method. The rate of formation of dioxo-bridged binuclear molybdenum(V) complexes with solvent water follows the rate law, rate = k$[Mo_2O_3(bipy)_2(NCS)_4]\;[H_2O]$. The reaction mechanism for the formation of dioxo-bridged complex is discussed. The observed negative volume of activation shows that the complex is strongly attracted to the solvent molecules at transition state.

• Applied Chemistry for Engineering
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• v.25 no.5
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• pp.531-537
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• 2014

A catalytic plasma reactor was employed for the oxidation of isopropyl alcohol (IPA) classified as a volatile organic compound (VOC). Copper oxide (Cu : 0.5% (w/w)) supported on a multichannel porous ceramic consisting of ${\alpha}-Al_2O_3$ was used as a catalyst, which was directly exposed to the plasma created in it. The effects of discharge voltage and reaction temperature on the concentrations of IPA and its byproducts were examined to understand the behavior of the catalytic plasma reactor. Without thermal insulation, the reactor temperature increased up to $120^{\circ}C$ at an applied voltage of 17 kV (discharge power : 28 W), and the IPA at a flow rate of $1L\;min^{-1}$ ($O_2$ : 10% (v/v); IPA : 1000 ppm) was completely removed. At temperatures below $120^{\circ}C$, however, besides the desirable product $CO_2$, several unwanted byproducts such as acetone, formaldehyde and CO were also formed from IPA. On the other hand, when the reactor was thermally insulated, the plasma discharge increased the temperature up to $265^{\circ}C$ under the same condition and most of IPA was oxidized to $CO_2$. Without loading CuO on the ceramic support, the plasma discharge in the thermally insulated reactor produced nearly equal amounts of $CO_2$ and CO. On comparison, with the catalyst alone (temperature : $265^{\circ}C$), more than 70% of the removed IPA was simply converted into another type of VOC (acetone), indicating that the catalyst assisted by the plasma is more effective in the oxidation of IPA than that of the catalyst-alone process.

• Journal of Life Science
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• v.21 no.5
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• pp.678-683
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• 2011

The objective of this study was to evaluate the skin inflammation effects of three herb mixture extracts, Ligularia fischeri, Solidago virga-aurea and Aruncus dioicus, which are from Ullung island in Korea. Regulatory mechanisms of cytokines and nitric oxide (NO) are involved in the immunological activity of Raw 264.7 cells. Tested cells were pretreated with 70% acetone extracts of Ligularia fischeri, Solidago virga-aurea and Aruncus dioicus (LSA-A) and further cultured for an appropriated time after lipopolyssacharide (LPS) addition. During the entire experimental period, 1, 10, and 100 ${\mu}g/ml$ of LSA-A had no cytotoxicity. In these concentrations, LSA-A inhibited the production of NO and prostaglandin $E_2$ ($PGE_2$), tumor necorsis factor-a (TNF-a), interleukin-1${\beta}$ (IL-1${\beta}$), interleukin-6 (IL-6) expression of inducible NO synthase (iNOS), and cyclooxygenase-2 (COX-2). LSA-A showed a 60% $PGE_2$ inhibition rate at 100 ${\mu}g/ml$. iNOS and COX-2 inhibition activities were 54%, and 65% at 100 ${\mu}g/ml$, respectively. In addition, LSA-A extract reduced the release of inflammatory cytokines including TNF-a, IL-1${\beta}$ and IL-6. These results suggest that LSA-A may have significant effects on inflammatory factors, and may be a potential anti-inflammatory therapeutic agent.

• Journal of Korean Society of Forest Science
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• v.99 no.4
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• pp.546-552
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• 2010

The aim of the study was to assess the cosmeceutical activity of Pyrus ussuriensis leaves and it is possible that can be used as a cosmetic ingredient for application of cosmetic industries. P. ussurensis leaf was extracted with various solvents including water, 70% ethanol and 60% acetone. In the result of DPPH (1,1-diphenyl-2-picryl-hydrazyl) scavenging radical activity, water, ethanol and acetone extract of P. ussuriensis leaf were higher than 70%, 80% and 85% at 50 ppm concentration, respectively. Xanthine oxidase inhibition activity and superoxide dismutase (SOD)-like activity by P. ussuriensis extract were higher than 30%. In addition, SODlike activity of all extracts showed tendency of the significant increase with the increase of concentration. In the anti-inflammatory test, P. ussuriensis leaf extract inhibited generation of nitric oxide (NO) stimulated by LPS in the macrophage cell line (raw 264.7) after 12 to 24 hours. As above results, P. ussuriensis has a great potential as a cosmeceutical raw material as well as anti-oxidant and anti-inflammatory ability.

• Journal of the Korean Chemical Society
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• v.27 no.2
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• pp.142-149
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• 1983

Reaction of thianthrene cation radical perchlorate (1) with cumene (4), p-chlorocumene (2), and p-nitrocumene (3) hydroperoxides in acetonitrile at room temperature afforded, inter alia, thianthrene as a common product and 5-(4'-hydroxyphenyl) thianthrenium perchlorate (5) for 4, 5-(5'-chloro-2'-hydroxyphenyl) thianthrenium perchlorate (7) and 5-acetonylthianthrenium perchlorate (6) for 2 and 6 for 3, respectively. Stoichiometry of these reactions showed that 2 moles of 1 gave rise to 1mole of thianthrene and 1 mole of thianthrenium salt (or salts). Nucleophilic reactivity to 1 was found to be in the order of phenol > > p-chlorophenol ${\sim}$ acetone > > p-nitrophenol. Apart from acid-catalyzed heterolytic decomposition of hydroperoxides, small amount of homolytic decomposition products were found from 3 and 4.

• Journal of the Korean Chemical Society
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• v.26 no.2
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• pp.107-113
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• 1982

Addition of dimedone to thioxanthylium ion generated from the oxidation of thioxanthene by thianthrene cation radical perchlorate in acetonitrile gave 9-(4,4-dimethylcyclohexane-2,6-dionyl)thioxanthylium perchlorate (2), whereas from the reverse addition between two reactants was obtained initially 9-(4,4-dimethylcyclohexane-2,6-dionyl)thioxanthene (1), which then underwent further reaction to give 2. The compound 2 was readily deprotonated in aq acetone to give 9-(4,4-dimethylcyclohexane-2,6-dionylidene)thioxanthene (3). However, 3 turned out to be in equilibrium with 2 in which three isosbestic points at 219, 289, and 348 nm were recorded in aq acetonitrile. The intensity and the position of the maximum absorption of 3 near 380 nm vary depending on the solvents which has been explained in terms of the solvent-solute interactions.

• Journal of the Korean Chemical Society
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• v.21 no.4
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• pp.293-303
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• 1977

Cellulosic organic solid wastes such as bark and sawdust, and filter papers as a pure cellulose were pyrolyzed at $300^{\circ}C$ under nitrogen current and mixed current of nitrogen and air. Amounts of condensates collected in air, water, and dry ice-acetone cooling traps, noncondensable gases, and carbonized residues were surveyed. The components of volatile liquids condensed in dry ice-acetone trap were separated by means of gas chromatograph and identified by retention times and syringe reactions. Pyrolysis under nitrogen current produced 13.4∼29.6${\%}$ of tar, 0.01∼0.12${\%}$ of aqueous liquids, 0.24∼1.43${\%}$ of volatile liquids, 9.84∼42.41${\%}$ of noncondensable gases, and 44.0∼65.81${\%}$ of carbonized residues. Pyrolysis under mixed current decreased tar and condensable liquids, but increased noncondensable gases.Volatile liquids collected under nitrogen current separated into the same 19 components by Porapak Q column regardless of the materials and only difference among materials was relative amounts of components. Volatile liquids collected under mixed current separated into six components and mainly lower molecular weight compounds such as methanol and formaldehyde were produced. According to the retention times and syringe reactions, methanol, formaldehyde, acetone, acetaldehyde, acetic acid, and three other compounds presumably containing hydroxyl group in the molecular structure were identified out of 19 compounds.

• Analytical Science and Technology
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• v.17 no.3
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• pp.263-270
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• 2004

A method is described for the analysis of short-chain alkylphenol ethoxylates (APEOs), 4-octylphenol-di-ethoxylate (OP2EO) and 4-nonylphenol-di-ethoxylate (NP2EO), in drinking water or wastewater using reversed phase high-performance liquid chromatography with electrospray ionization mass spectrometry. The solvent system was water and methanol containing $10{\mu}M$ trifluoroacetic acid as an ionization solvent. We acidified 1 L of water samples to less than pH 2 with concentrated $H_2SO_4$ and loaded onto Sep-Pak $C_{18}$, and eluted with acetone. The calibration of OP2EO and NP2EO was performed for the concentration range from 20 to 500 ng/L and the correlation coefficients were 0.999 and 0.990, respectively. The limits of detection were 20 ng/L (OP2EO) and 50 ng/L (NP2EO) at a signal-to-noise ratio of 3. Accuracy and precision of this analytical method were 85.8 ~ 122.1% and 8.2 ~ 18.8%, respectively. The proposed method allowed a sensitive and rapid detection of OP2EO and NP2EO and it could be applied for monitoring of APEOs from environmental samples.