• Bulletin of the Korean Chemical Society
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• v.12 no.4
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• pp.429-433
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• 1991

The photoinduced electron transfer reactions of N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) in various polar solvents were studied by measuring time-resolved fluorescence. The temperature dependence on the fluorescence decay rate in acetonitrile, methanol, ethanol and buthanol was carried out to obtain the activation energy and Arrehnius factor for the photoinduced electron transfer reaction. It was found that as the dielectric constant of the solvent increases, the activation energy and the reaction rate increase. This implys that the Arrehnius factor is important in controlling the photoinduced electron transfer reaction rate. In water, TMPD exists in three forms (cationic, protonated and neutral forms) due to the high dielectric constant and strong proton donating power of water. The photoinduced electron transfer reaction was found to be very fast (< 50 ps) and also the long liverd component in the fluorescence decay profile attributable to the photoexcited protonated form of TMPD was observed. Probably, the reaction pathway and the reaction coordinate seem to be different depending on the solvents studied here.

• Applied Chemistry for Engineering
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• v.10 no.8
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• pp.1210-1215
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• 1999

Optimum conditions of the hydrogenation of PNA to pure PPD were determined in a three-phase slurry reactor with suspended Pd/C catalyst particles. Minimization of mass transfer resistances at the interfaces of both gas-liquid and liquid-catalyst particles and control of overall reaction rate on catalyst surface leaded to decrease the hydrogen starvation on reaction active sites and to reduce the side reactions during hydrogenation. The optimum temperature, pressure, and catalysst concentration were confirmed to be in the range of $60^{\circ}C$, 60~70 psig, and 1~2 g-cat/L, respectively. Reaction rate was zero order with respect to the concentration of PNA and 1st order with respect to the pressure of hydrogen(P). Overall rate expression of the reaction was $R_A=6.44{\times}10^6{\cdot}H{\cdot}P{\cdot}m{\cdot}$exp(-4659/T) where H is constant, m is concentration of catalyst, and T is temperature.

• Membrane Journal
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• v.24 no.2
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• pp.100-106
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• 2014

In this work, soluble polyimides were synthesized and characterized from 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride (DOCDA) and two diamines such as 4,4'-diaminodiphenylether (ODA), 1,4-phenylenediamine (p-PDA). Their thermal properties were analyzed with differential scanning calorimeter (DSC). The gas permeability coefficients (P) and ideal selectivity for $CH_4$ and $CO_2$ of the prepared polyimide membranes were measured with a time-lag apparatus. DOCDA-ODA, DOCDA-p-PDA showed good permeability and selectivity; the permeabilities of $CO_2$ was 6.10, 0.74 barrers and the selectivity of $CO_2/CH_4$ were 67.03, 46.25, respectively. Therefore, DOCDA-ODA showed good possibility as gas separation membrane.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.8
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• pp.1010-1015
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• 2006

p-Pheylenediamimine (PPD) is one of hair dye's ingredients, and the mixture of PPD with hydrogen peroxide is generally used to dye hair at beauty shop. This study is conducted to investigate the effect of oxidized PPD on rat skin. 6% hydrogen peroxide, PPD (5% PPD in 2% $NH_4OH$) or the mixture (isovolumed mixture of 5% PPD and 6% hydrogen peroxide in 2% $NH_4OH$) was applied to rat skin ($25\;mg/16.5\;cm^2$) five times every other day. The activity of acid phosphatase (ACP) was more increased in the mixture of PPD with hydrogen peroxide applied group than PPD applied group. Furthermore, the activity of glucose 6-phosphatase (G6Pase) in the mixture of PPD with hydrogen peroxide applied group showed higher decreasing rate than that of PPD applied group. In histopathological findings, the mixed PPD with hydrogen peroxide applied group showed more thickening of epithelium, increased numbers of dermal fibroblasts, and the dilatation of dermal capillaries than PPD applied group. The significant increasing of xanthine oxidase (XO) activity was determined in mixture of PPD with hydrogen peroxide applied group compared with PPD applied group. However, reactive oxygen species (ROS) scavenging system, the activities of superoxide dismutase (SOD) and glutathione S-transferase (GST) were more significantly decreased in mixed PPD with hydrogen peroxide applied groups than in PPD applied group. In conclusion, topical application with the mixture of PPD with hydrogen peroxide compared with PPD application resulted in imbalance with ROS generating and scavenging which probably led to severe skin injury.

• Applied Chemistry for Engineering
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• v.26 no.3
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• pp.377-380
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• 2015

In this paper, we have investigated the optimization of $I_2$ recovery process from $NH_4I$ solution, which is generated as by-product during the amination reaction of p-diiodobenzene (PDIB) for p-phenylenediamine (PPD) synthesis. The recovered $I_2$ is then recycled as a raw material for PDIB synthesis. We have employed a cation exchange resin to recover $I_2$ from $NH_4I$ sample solution, and determined the breakthrough point and exchange capacity from the breakthrough curve. Furthermore, we have suggested optimum conditions of our $I_2$ recovery process by measuring the purity and yield of recovered $I_2$ with respect to the concentrations of $NH_4I$ and oxidant ($H_2O_2$) solutions, the oxidation time, and the temperature of drying process. Finally, the yield and purity as high as 94.96% and 96.65%, respectively were obtained by reusing the residual solution still containing unrecovered iodide ions.

• Applied Biological Chemistry
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• v.30 no.3
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• pp.285-290
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• 1987

As a basic research for inhibition of enzymatic browning of apples during dehydration or processing, peroxidase was extracted from Fuji apples to investigate heat inactivation, and chemical inhibition. Peroxidase showed the highest activity at $35^{\circ}C$ and pH 5.5 using substrates of p-phenylenediamine and $H_2O_2$. The thermal inactivation followed biphasic kinetics to have activation energy (Ea) of 48.2kcal/mol and z value of $11.2^{\circ}C$ for the heat labile fraction and Ea of 36.3kcal/mol and z value of $14.9^{\circ}C$ for the heat resistant fraction. Browning by peroxidase was completely inhibited at the concentrations of 10mM for sodium diethyldithiocarbamate and potassium metabisulfite and 1mM for L-cysteine and ascorbic acid.

• Analytical Science and Technology
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• v.8 no.3
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• pp.249-258
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• 1995

The polymers, polyazine, polyazomethine ( I ) and polyazomethine ( II ) were prepared by the condensation of p-benzoquinone with hydrazine hydrate, p-phenylenediamine and diaminomaleonitrile in DMSO, respectively. The IR spectra of these polymers showed a characteristic peak of schiff base (-C=N-) at about $1600cm^{-1}$. These polymers dissolved in concentrated sulfuric acid showed UV/VIS absorption near 300nm indicatiog the presence of iminium ion(>$C\limits^{\small\oplus}=NH-$). Another UV/VIS absorption band in the region of 350~415nm was shown presumably due to the charge transfer transition in the molecule. The electrical conductivities of polyazine, polyazomethine ( I ) and ( II ) were measured. The self-electrical conductivity of these was found to be about $10^{-14}{\sim}10^{-11}{\Omega}^{-1}cm^{-1}$ and these polymers doped with $I_2$ showed the maximum conductivity of about $10^{-2}{\Omega}^{-1}cm^{-1}$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.1
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• pp.84-90
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• 1992

Peroxidase in the fruit of Malus sieboldii (Regel) Rehder was partially purified by DEAE-cellulose column chromatography and Ultro-AcA 54 gel filtration. The optimum pH of peroxidase was 4.5 and optimum temperature was $80^{\circ}C$. The enzyme was stable at pH 5.0 and below $30^{\circ}C$, and inactivated by heat treatment at $80^{\circ}C$ for 15min. In the presence of 30mM $H_{2}O_2$ Km value on o-phenylenediamine as substrate was 1.65mM, and in the presence of 10mM o-phenylenediamine Km value on $H_{2}O_2$ was 7.97mM. L-Ascorbic acid and sodium L-ascorbate greatly inhibited the enzyme activity and among several metal ions $Mn^{2+}$ only increased the activity at 5mM.

• Polymer(Korea)
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• v.34 no.6
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• pp.553-559
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• 2010

The paper describes the preparation and characterization of conductive polyaniline-modified polymers by growing of aniline onto functionalized poly(styrene-co-p-methylstyrene) [P(St-co-MSt)]. For this purpose, P(St-co-MSt) was synthesized via nitroxide mediated radical polymerization (NMRP) and then N-boromosuccinimide was used for introduction of bromine to the benzylic positions of copolymer. Afterwards, 1,4-phenylenediamine was linked to the brominated P(St-co-MSt) and functionalized copolymer $[P(St-co-MSt)-NH_2]$ was prepared. The graft copolymerization of aniline monomers onto functionalized P(St-co-MSt) was initiated by oxidized phenylamine groups after addition of ammonium peroxydisulfate (APS), and p-toluenesulfonic acid-doped PANI was chemically grafted onto P(St-co-MSt) via oxidation polymerization. The obtained terpolymer was studied by FTIR and UV-Vis spectroscopy and its thermal behaviour were examined by DSC and TGA analyses. The conductivity of terpolymer was measured by four-point probe method and electroactivity was measured by cyclic voltammetry (CV). The solubility of P(St-co-MSt)-g-PANI was examined in common organic solvents.

• Advances in nano research
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• v.11 no.6
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• pp.667-678
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• 2021

Multiwalled carbon nanotubes (MWCNTs) were first oxidized (O-CNTs) to introduce carboxylic group and then further functionalized (F-CNTs) with m-phenylenediamine, which was confirmed by FTIR and SEM. It was used as an effective adsorbent for the adsorptive removal of diclofenac drug from water. Under optimum conditions of pH 6, stirring speed 600 rpm, the maximum adsorption capacity obtained was 532 mg g^-1 which is superior to the values reported in literature. The adsorption was quite rapid as 25 mg L^-1 drug solution was adsorbed in only 3 minutes of contact time with 10 mg of adsorbent dose. The adsorption kinetics and isotherms were studied using various models to evaluate the adsorption process. The results showed that the data best fit in kinetics pseudo-second order and Langmuir isotherm model. Furthermore, the oxidized and functionalized MWCNTs were applied on gram-negative Escherichia coli and gram-positive Staphylococcus aureus using agar disc diffusion assay to validate their anti-microbial activity. Results were unique as both oxidized and functionalized MWCNTs were equally active against both E. coli and S. aureus. The newly synthesized F-CNTs have great potential in water treatment, with their dual action of removing drug and pathogens from water, makes it potential applicant to save environment.