• Analytical Science and Technology
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• v.36 no.5
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• pp.224-235
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• 2023

An analytical method was developed for the determination of phenol (P) and the seven substituted phenols in water samples and fish tissue samples collected from three streams located in eastern Gangwon State in spring and summer. The phenols were extracted and then derivatized to phenyl acetates using acetic anhydride. The derivatives were subsequently identified and quantified using gas chromatography coupled with mass spectrometry. P and 4-nitrophenol (4NP) were found at relatively high levels in water, ranging from below the method detection limit (MDL) to 3.32 ㎍/L and from < MDL to 4.91 ㎍/L, respectively. P and 4NP were also the dominant compounds in the fish tissue, ranging from < MDL to 407 ㎍/kg and from < MDL to 870 ㎍/kg, respectively. Phenol concentrations were significantly higher in spring than in summer. The ecological risk quotient calculated for P was higher than 4NP but not high enough to pose any risk of adverse effects to fish health.

• Journal of the Korean Applied Science and Technology
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• v.29 no.3
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• pp.429-434
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• 2012

A kind of Antihistamines, Azelastine HCl which known as modern H1-blockers, was synthesized by four step process using phthalic anhydride, 4-chlorophenylacetic acid, hydrazine 2HCl. The first step was the reaction of removing carboxyl group and hydroxyl group and the second step was saponification of 3-(4-chlorobenzylidene)phthalide. The third step was the nucleophilic addition reactions of primary amines and the fourth step was addition reaction of N-methyl-1-aza-bicyclo[3,2,0]heptane to 4-(4-chlorobenzyl)-1-(2H)phthalazinone. As a result, product was analyzed by FT-IR and $^1H$-NMR and could be obtained with a yield of 80%.

• The Korean Journal of Mycology
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• v.31 no.3
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• pp.168-174
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• 2003

In this study, Cordyceps militaris was grown in a liquid medium containing colloidal chitin. A chitinase was purified from the supernatant or cultured medium by ammonium sulfate fractionation, DEAE-Sephadex A-25 and Sephadex G-50 column chromatography. Optimum temperature and pH of this enzyme were $35^{\circ}C$ and 5.5, respectively. The molecular weight of the chitinase was estimated to be 48.5 kDa by SDS-PAGE and its Km value was 0.57 mM. The activity of this enzyme was inhibited by $Cu^{2+},\;Mn^{2+},\;Hg^{2+},\;Zn^{2+},\;CO_{3}^{2-},\;SO_4^{2-},\;CN^-,\;ion,\;and\;OCN^-$ maleic anhydride, acetic anhydride or N-bromo succinimide, especially strongly inhibited by sodium cyanate for 84.0 percentage. But its activity wag slightly stimulated by $Mg^{2+}\;and\;K^+$ ion, respectively. The products formed during hydrolysis of the hexa-N-acetylchitohexaose with this enzyme were N,N'-diacetylchitobiose and N,N',N'-triacetylchitotriose. These results imply that this purified enzyme may be an endo-chitinase.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.10
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• pp.1525-1531
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• 2016

The objective of the present study was to investigate the rheological properties of potato starch cross-linked with different concentrations (0, 0.125, 0.25, and 0.5%, w/v) of cross-linking agents (10 g of adipic acid and 40 g of acetic anhydride). Cross-linked potato starch dispersions showed shear-thinning behaviors (n=0.43~0.63) at $25^{\circ}C$. Apparent viscosity (${\eta}_{a,100}$), consistency index (K), and yield stress (${\sigma}_{oc}$) significantly increased with an increase in the concentrations of cross-linking agents from 0.125 to 0.5% (w/v). Storage modulus (G') and loss modulus (G'') increased, whereas complex viscosity (${\eta}^*$) was reduced with increasing frequency (${\omega}$) from 0.63 to 62.8 rad/s. Magnitudes of G' and G'' for cross-linked potato starch were significantly increased with an elevation in the concentrations of cross-linking agents. G' values of cross-linked potato starches were significantly higher than G'', indicating that the starches had more elastic properties than viscous properties. Cox-Merz rule was not applicable to potato starch dispersions.

• Membrane Journal
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• v.25 no.3
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• pp.223-230
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• 2015

We synthesized novel polyimides with high gas permeability and selectivity for application of gas separation membrane. 2,2-bis(3,4-carboxylphenyl) hexafluoropropane dianhydride (6FDA) and two kinds of amines with high permeability and solubility were used to prepare the novel polymide. 2,4,6-Trimethyl-1,3-phenylenediamine (DAM) was used to improve gas permeability and 4,4-Methylenedianiline was used to improve the gas selectivity respectively. The polyimide copolymers were synthesized by commercial chemical imidization method using Triethylamine and Acetic anhydride and their average molecular weights were over 100,000 g/mol. The glass temperature (Tg) and the thermal degradation temperature were characterized using differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA). The synthesized copolymers showed high Tg over $300^{\circ}C$ and high thermal degradation temperature over $500^{\circ}C$. The gas permeation properties were measured by time-lag equipment. Although general polyimides showed very low gas permeability, synthesized polyimide copolymer showed high $O_2$ permeability of 10.1 barrer with high $O_2/N_2$ selectivity around 5.3. From this result, we confirm that these membranes have possibility to apply to gas separation membrane.

• Journal of the Korean Chemical Society
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• v.30 no.4
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• pp.369-376
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• 1986

Diosgenin in an Indonesian Costus speciosus was determined by capillary gas-liquid chromatography (GLC). The experimental conditions for the hydrolysis, extraction and acetylation of the diosgenin, and the determination by GLC were investigated. 0.20g of dried sample powder was refluxed in the solution of 3N HCI and xylene at 95∼100${\circ}C$ for 4 hours and the xylene layer was separated. The residue evaporated the xylene was refluxed in 20 : 80 acetic anhydride-pyridine for 30 minutes and the diosgenin acetate was extracted with diethyl ether. Dehydrated with anhydrous $Na_2SO_4$ and evaporated the ether, the residue was dissolved in 5.00ml of n-hexane and injected into GLC. Capillary column of SE-30 25m ${\times}$ 0. 33mm was installed in GLC and the column temperature was increased from 180${\circ}$ to 270${\circ}C$ at rate of 10${\circ}C$/min. The flow rate of carrier gas $N_2$ was 2ml/min and FID was used to detect. The analytical result of the diosgenin was 0.281% and relative standard deviation of 5 measures was 1.8%.

• Membrane Journal
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• v.16 no.1
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• pp.39-50
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• 2006

Porous chitosan and chitin membranes were prepared by using silica particles as porogen. Membrane preparation was achieved via the following three steps: (1) chitosan film formation by casting an chitosan solution containing silica particles, (2) preparation of porous chitosan membrane by dissolving the silica particles by immersing the film into an alkaline solution and (3) preparation of porous chitin membrane by acetylation of chitosan membrane with acetic anhydride. The optimum preparation conditions which could provide a chitosan and chitin membranes with good mechanical strength and adequate pure water flux were determined. To allow protein affinity, a reactive dye (Cibacron Blue 3GA) was immobilized on porous chitosan membrane. Binding capacities of affinity chitosan and chitin membranes for protein and enzyme were determined by the batch adsorption experiments of BSA protein and lysozyme enzyme. The maximum binding capacity of affinity chitosan membrane for BSA protein is about 22 mg/mL, and that of affinity chitin membrane for lysozyme enzyme is about 26 mg/mL. Those binding capacities are about $several{\sim}several$ tens times larger than those of chitosan and chitin-based hydrogel beads. Those results suggest that the porous chitosan and chitin membranes are suitable in affinity filtration chromatography for large scale separation of proteins.

• Korean Journal of Environmental Agriculture
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• v.13 no.3
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• pp.271-278
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• 1994

Mode of safening action of N-(4-chlorophenyl)maleimide (CPMI) on metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-l-methylethyl) acetamide] was investigated in sorghum(Sorghum bicolor L.). CPMI was synthesized by dehydration of N-(4-chlorophenyl)maleamic acid (CPMA) which was obtained from amination with maleic anhydride and 4-chloroaniline. Melting points of CPMA and CPMI (>95% purity) were $200-202^{\circ}C$ and $116-118^{\circ}C$, respectively. Growth response study indicated that seed treatment of CPMI increased tolerance of sorghum shoot to metolachlor approximately threefold. Sorghum shoot was more sensitive to injury caused by metolachlor and CPMI activity than the root. Metolachlor was initially absorbed by sorghum shoot and metabolized to the metolachlor-glutathione conjugate in CPMI-untreated and treated shoots. However, CPMI treatment significantly accelerated metabolism of $[^{14}C]$metolachlor in sorghum shoot, resulting in decrease in metolachlor content and increase in formation of the glutathione conjugate. It was concluded that the protection against metolachlor injury conferred by CPMI appeared to be correlated to detoxification of metolachlor in sorghum shoot tissue.

• Journal of the Korean Chemical Society
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• v.30 no.6
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• pp.548-552
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• 1986

A stereoselective synthesis of 3-phenoxybenzyl (${\pm}$)-cis and trans-3-(2,2-dichlorovinyl)-2,2-dimethyl-1-cyclopropanecarboxylic acid starting from readily available 2-methyl-3-buten-2-ol($\underline{2}$) is described. Allylic rearrangement of 2-methyl-3-buten-2-ol, in the presence of acetic acid and acetic anhydride gave 3-methyl-2-butenyl acetate($\underline{3}$). The [3,3] sigmatropic rearrangement of the allyl acetate($\underline{3}$), as the silylketene acetal, produced the ${\gamma},\;{\delta}$-unsaturated acid($\underline{4}$). Treatment of 3,3-dimethyl-4-pentenoic acid($\underline{4}$) with SOCl2 followed by esterification with 3-phenoxybenzyl alcohol yielded 3, 3-dimethyl-4-pentenoic acid ester($\underline{5}$). Addition of carbon tetrachloride to the olefin ester($\underline{6}$) furnished 4,6,6,6-tetrachloro-3,3-dimethylhexanoic acid ester ($\underline{7}$). Cyclization with potassium t-butoxide and elimination of hydrogen chloride afforded 3-phenoxybenzyl (${\pm}$) cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethyl-1-cyclopropanecarboxylic acid.

• Current Photovoltaic Research
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• v.4 no.1
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• pp.8-11
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• 2016

Strong deep ultraviolet emitting aniline and $TiO_2$ composite has been synthesized via hydrolysis and condensation reactions of titaniumisopropoxide ($Ti(OPr)_4$), aniline, and acetic anhydride. Three different weight ratios of aniline and $Ti(OPr)_4$ including 3:1 ($TiO_2An-A$), 2:1 ($TiO_2An-B$), and 1:1 ($TiO_2An-C$) were synthesized and characterized their optical properties. The FTIR spectra of the $TiO_2An-A$, -B, and -C showed the absorption intensities of the benzene ring stretching and bending vibrations, and benzene ring -CH stretching, bending, and deformation vibrations increased with the increase of the amount of aniline. The UV-visible absorption spectra showed that the UV region absorption was slightly increased with the increase of the amount of aniline. The photoluminescence (PL) intensities were exponentially increased with the increase the excitation wavelength from 307 to 317 nm, steadily increased from 300 to 313 nm and slowly increased from 302 to 308 nm for $TiO_2An-A$, -B, and -C, respectively and decreased thereafter. Therefore, the PL intensity is strongly dependent on the weight ratio of $Ti(OPr)_4$ and aniline.