• Journal of Environmental Science International
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• v.20 no.1
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• pp.119-126
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• 2011

In this study, reaction model and reactions rate accelerated by o-iodosobenzoate ion(IB$^{\ominus}$) on hydrolysis reaction of p-nitrophenyl valate(NPV) using ethyl tri-octyl ammonium mesylate(ETAMs) for quaternary ammonium salts, the phase transfer catalysis(PTC) reagent, were investigated. The effect of IB$^{\ominus}$ on hydrolysis reaction rate constant of NPV was weak without ETAMs solutions. Otherwise, in ETAMs solutions, the hydrolysis reactions exhibit higher first order kinetics with respect to the nucleophile, IB$^{\ominus}$, and ETAMs, suggesting that reactions are occurring in small aggregates of the three species including the substrate(NPV), whereas the reaction of NPV with OH$^{\ominus}$ is not catalyzed by ETAMs. Different concentrations of NPV were tested to measure the change of rate constants to investigate the effect of NPV as substrate and the results showed that the effect was weak. This means the reaction would be the first order kinetics with respect to the nucleophile. This behavior for the drastic rate-enhancement of the hydrolysis is referred as 'Aggregation complex model' for reaction of hydrophobic organic ester with o-iodosobenzoate ion(IB$^{\ominus}$) in hydrophobic quarternary ammonium salt(ETAMs) solutions.

• Journal of the Korean Chemical Society
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• v.18 no.6
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• pp.430-436
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• 1974

The rate constants of hydrolysis of 1,1-dicyano-2-p-dimethylaminophenyl-2-chloroethylene(DPC) were determined at various pH and the rate equation which can be applied over wide pH range is obtained. From the rate equation the mechanism of the hydrolysis of a DPC over wide pH range is fully explained; below pH 3 and above pH 7.5, the rate constant is proportional to the concentration of hydronium ion and hydroxide ion, respectively. However, in the range of pH 3 to 7.5, water, hydronium ion and hydroxide ion catalyze the hydrolysis of DPC.

• Textile Coloration and Finishing
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• v.14 no.4
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• pp.214-222
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• 2002

In order to give a silk-like touch to PET fabrics, the PET fabrics were treated with NaOH alkaline solution in various conditions. In alkaline treatment, the liquor flow type pilot weight reduction apparatus with magnetostrictive ultrasonic transducer was used for the study. The weight loss of PET fabrics hydrolyzed in 4% and 6% NaOH solution, at $95^\circ{C}$ and $99^\circ{C}$ for 60min. with ultrasonic application showed 3.7~4.6% higher than that of treated fabric without ultrasonic application. From the difference of specific weight loss, the treatment condition of the maximum of hydrolyzation effect appeared at $95^\circ{C}$ in $4^\circ{C}$ and at $90^\circ{C}$ in 6% NaOH solution, respectively. During the alkali hydrolysis of PET fabrics, the decomposition rate constant(k) increased exponentially with the treatment temperature and were not related with ultrasonic cavitation. The activation energy$(E_a)$ in decomposition of PET fabrics were 21.06kcal/mol with ultrasonic application and 21.10kcal/mol without ultrasonic application. The ultrasonic application gave a little higher value of the activation entropy$(\Delta{S}^\neq)$ and a little lower value of Gibbs free energy$(\Delta{S}^\neq)$ compared with not used ultrasonic apparatus.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.4
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• pp.457-468
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• 2013

Based on the activated sludge model(ASM), a mathematical model which represents the aerobic sludge digestion by sequencing batch reactor(SBR) combined with ultrasonic treatment was composed and performed in this study. Aerobic digestion using sequencing batch reactor(SBR) equipped with ultrasound treatment was also experimented for the purpose of parameter calibration. Most of the presented kinetic parameters in ASM or ASM2 could be used for the aerobic digestion of sludge but the parameters related in hydrolysis and decay rate needed modification. Hydrolysis rate constant of organic matter in aerobic condition was estimated at $0.3day^{-1}$ and the maximum growth rate for autotrophs in aerobic condition was $0.618day^{-1}$. Solubilization reactions of particulate organics and nitrogen by ultrasonication was added in this kinetic model. The solubilization rate is considered to be proportional to the specific energy which is defined by specific ultrasound power and sonication time. The solubilization rate constant by ultrasonication was estimated at $0.202(W/L)^{-1}day^{-1}$ in this study. Autotrophs as well as heterotrophs also decomposed by ultrasonic treatment and the nitrification reaction was limited by the lack of autotrophs accumulation in the digester.

• Journal of Environmental Science International
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• v.17 no.5
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• pp.509-516
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• 2008

New functional surfactant, N,N-dimethyl-N-dodecyl-N-(2-methyl benzimidazoyl) ammonium chloride(DDBAC) having benzimidazole(BI) functional group have been synthesized and the critical micellar concentration of DDBAC measured by surface tentiometry and electric conductivity method was $8.9{\times}10^{-4}M$. Micellar effects in DDBAC functional surfactant solution on the hydrolysis of p-nitrophenylacetate(p-NPA), p-nitro-phenylpropionate(p-NPP) and p-nitrophenylvalerate(p-NPV) were observed with change of various pH (Tris-buffer). The pseudo first rate constants of hydrolysis of p-NPA, p-NPP and p-NPV in optimum concentration of DDBAC solution increase to about 160, 280 and 600 times, respectively, as compared with those of aqueous solution at pH 8.00(Tris-buffer). It is considered that benzimidazole functional moiety accelerates the reaction rates of hydrolysis because they act as nucleophile or general base. In optimum concentration of DDBAC solution, the rate constants of hydrolysis of p-NPP and p-NPV increase to about 1.5 and 3.0 times, respectively, as compared with that of p-NPA. It means that the more the carbon numbers of alkyl group of substrates, the larger the binding constants between DDBAC micelle and substrates are. To know the hydrolysis mechanism of p-NPCE(p-NPA, p-NPP and p-NPV), the deuterium kinetic isotope effects were measured in $D_2O$ solutions. Consequently the pseudo first order rate constant ratios in $H_2O$ and $D_2O$ solution, $k_{H_2O}/k_{D_2O}$, were about $2.8{\sim}3.0$ range. It means that the mechanism of hydrolysis were proceeded by nucleophile and general base attack in approximately same value.

• Journal of the Korean Chemical Society
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• v.38 no.4
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• pp.265-270
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• 1994

The aquation and base hydrolysis of [Co(en)$_2$NH$_3$Cl]$^{2+}$ were studied by UV spectroscopic method in various SDS aqueous solution. The base hydrolysis of [Co(en)$_2$NH$_3$Cl]$^{2+}$ with the addition of 0, 0.05, 0.1 mol dm$^{-3}$ sodium chloride was studied. For the aquation of the complex, the rate constant in the micellar phase(kH$^M$) was a little larger than that in the aqueous phase(kH$^W$). With the increase of SDS concentration, the second order rate constant(kOH) for the base hydrolysis unchanged below the CMC and sharply decreased down to a limiting value after the CMC was reached. The effect of added NaCl on the rate behavior of the complexes in the micellar solution were investigated by using an ion-exchanged model.

• Journal of the Korean Society of Clothing and Textiles
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• v.20 no.3
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• pp.550-559
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• 1996

The Effect of protease (subtilisin Carlsberg) on the removal of hemoglobin as protein soil was studied. The hydrolysis characteristics of subtilisin Carlsberg was examined by electrophoretic techniques. The fragmentation patterns of hemoglobin were analyzed by SDS-PAGE. The hydrolysis efficiency was evaluated by analysis of protein bands shown on gels before and after hydrolysis by using densitometer. 1. The hydrolysis of hemoglobin by subtilisin Carlsberg was increased markedly with the increase of the enzyme concentration. 2. The hydrolysis of hemoglobin by subtilisin Carlsberg was effectively increased in proportion to increasing of the hemoglobin concentration up to a certain point, but it began to decrease above the point. 3. The hydrolysis of hemoglobin by subtilisin Carlsberg followed the first order kinetics, yielding a rate constant of $4.05\time10^{-4}S^{-1}s$. 4. The hydrolysis of hemoglobin by subtilisin Carlsberg was highest at $50^{\circ}C$ and was decreased markedly at $80^{\circ}C$. 5. The hydrolysis of hemoglobin was comparatively low at pH 7.0~8.0, and highest at pH 11.0.

• Archives of Pharmacal Research
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• v.19 no.5
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• pp.423-428
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• 1996

Optimum conditions for hydrolysis were investigated to enhance water-solubilities of protein-bound polysaccharides in the basidiocarps of Ganoderma lucidum by treating chymotrypsin. We also attempted with Ganoderma lucidum residue remaining after extracting hot water-soluble compoents in Ganoderma lucidum. After hydrolyzing under optimum conditions (20 ppm chymotrypsin, 2% Gampderma lucidum or 6% Ganoderma lucidum residue, at pH 10 and at $ 40^{\circ}C$), the amounts of total protein and carbohydrate of hydrolysate were measured. Michaelis constant, $K_{m}$, and maximum rate, $V_{max}$, calculated by Lineweaver-Buck plot for the hydrolysis of Ganoderma lucidum were 1.73% and 0.073%/min respectively and those for hydrolysis of Ganoderma lucidum residue were 2.40% and 0.033%/min respectively. The amount of polysaccharide isolated from Ganoderma lucidum (100 g) treated with chymotrypsin was only 3.07 g, but significantly increased amount (14.34 g) of polysaccharides was isolated from Ganoderma lucidum residue (100 g) treated with chymotrypsin. The protein-bound polysaccharide was isolated from the non-hydrolyzed and hydrolyzed sample and molecular weights of the polysaccharide were measured by Sepharose CL-48 gel filtration.

• Bulletin of the Korean Chemical Society
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• v.18 no.3
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• pp.300-305
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• 1997

Effect of a nonionic surfactant, Tween 20 on the adsorption and kinetic mechanism for the hydrolysis of a microcrystalline cellulose, Avicel PH 101, by endoglucanase Ⅰ (Endo Ⅰ) and exoglucanase Ⅱ (Exo Ⅱ) isolated from Trichoderma viride were studied. The Langmuir isotherm parameters, amount of maximum adsorption (Amax) and adsorption equilibrium constant (Kad) for the adsorption, were obtained in the presence and the absence of nonionic surfactant. On the addition of Tween 20, the Kad and Amax values of Exo Ⅱ were decreased, while those of Endo Ⅰ were not affected. These indicate that the adsorption affinity of Exo Ⅱ on the cellulose is weakened by nonionic surfactant, and the surfactant enhanced desorption of Exo Ⅱ from insoluble substrate. The enzymatic hydrolysis of the cellulose can be described by two parallel pseudo-first order reactions using the percentages of easily (Ca) and hardly (Cb) hydrolyzable cellulose in Avicel PH 101 and associated rate constants (ka and kb). The Ca value was increased by adding Tween 20 for all enzyme samples (Exo Ⅱ, Endo Ⅰ and their 1:1 mixture) implying that the low-ordered crystalline fraction in the cellulose may be partly dispersed by surfactant. The ka value was not affect by adding Tween 20 for all enzyme samples (Exo Ⅱ, Endo Ⅰ and their 1:1 mixture). The kb value of Exo Ⅱ was increased by adding Tween 20, while that of Endo Ⅰ was not affected. This suggests that the surfactant helps the Exo Ⅱ desorb from microcrystalline cellulose, and increase the hydrolysis rate. These results were show that the increase of hydrolysis of cellulose by the nonionic surfactant is due to both the activation of Exo Ⅱ and partial defibrillation of the cellulose.

• Archives of Pharmacal Research
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• v.19 no.4
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• pp.326-334
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• 1996

We investigated the optimum conditions for conversion of water-insoluble components of basidiocarps of Ganoderma lucidum to water-soluble components by hydrolyzing with chitinase. We also tried it with Ganoderma luciclum residue remaining after extracting hot water-soluble components of Ganoderma lucidum. After hydrolyzing under optimum conditions (20 ppm chitinase, 2% Ganoderma lucidum or 6% Ganoderma lucidum residue, at pH 3 and at $ 35^{\circ}C$), the contents of total water-soluble components (polysaccharide or protein) were measured, and it was found that the contents of water-soluble components increased to 1.5-2.7 fold. Michaelis constant, $K_m$ and maximum rate, $V_max$ calculated by Lineweaver-Burk plot for hydrolysis of Ganoderma lucidum were 1.75% and 0.02%/min respectively and those for hydrolysis of Ganoderma lucidum residue were 53.15% and 0.53%/min respectively The protein-bound polysaccharide was isolated after hydrolysis and molecular weights were measured by Sepharose CL-4B gel filtration and compared with the molecular weights of polysaccharide before hydrolysis.