• Journal of the Korean Chemical Society
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• v.29 no.5
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• pp.522-532
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• 1985

The reactions of p-nitrophenyldiphenylphosphate (p-NPDPP) with anions of benzimidazole (BI) and its 2-alkyl derivatives (R-BI) are strongly catalyzed by the micelles of cetyltrimethyl ammonium bromide (CTABr). On the other hand, the first order rate constants $(k'_{R-BI^-})$ and the second order rate constants $(k_{m(R-BI^-)})$ of the reactions mediated by R-$BI^-$in the micellar pseudophase are much smaller than those mediated by $BI^-$. In order to explain the slower rates of the micellar reactions mediated by R-$BI^-$, we compared the concentration-ratios ([R-$BI^-$]/[$BI^-$]) with the first order rate constant-ratios $(k'_{R-BI^-}/k'_{BI^-})$ and the second order constant-ratios $(k_{m(R-BI^-)}/k_{m(BI^-)})$ for the reactions taking place in the micellar pseudophase. The rate constant-ratios were much smaller than the concentration-ratios. For example in a 5 ${\times}10^{-4}$M butyl-BI solution, the two ratios were 0.089 and 0.430 (for the first order) respectively, and in a $10^{-4}$M butyl-BI solution the former was 0.100 (for the second order). This predicts that the reactivities of R-$BI^-$ in the micellar pseudophase are much smaller than that of $BI^-$. Based on the values of several kinetic parameters measured for dephosphorylation of p-NPDPP mediated by R-$BI^-$, a schemetic model is proposed. Due to the hydrophobicity and the steric effect of the alkyl substituents, these groups would penetrate into the core of the micelle for stabilization by van der Waals interaction with long cetyl groups of CTABr. Consequently, the movements of R-$BI^-$ bound to the micelle should be restricted, leading to decreased collison frequencies between the nucleophiles and p-NPDPP. We refer this as an "anchor effect". This effect became more predominent when a larger alky group in R-BI was employed and when a greater concentration of R-BI was used.

• Journal of Pharmaceutical Investigation
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• v.9 no.3
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• pp.9-21
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• 1979

This study was undertaken to establish the different pharmaceutical properties between promethazine HCl and promethazine pamoate. First, promethazine pamoate was prepared by using the modified method of Saias. Second, in order to study the different pharmacokinetics between promethazine pamoate and promethazine HCl, absorption rate, plasma concentration, and distribution, as well as urinary excretion of the both compounds were examined in rabbits as an experimental animal: The results were as follows. 1. In the in vitro isolated intestine of rabbit, the rate constant for absorption of promethazine pamoate was $0.347hr^{-1}$ and that of promethazine HCl was $0.532hr^{-1}$. 2. After oral administration of promethazine pamoate, the increase of plasma concentration of promethazine was much slower than that of promethazine HCl. 3. The urinary excretion rate of promethazine pamoate was significantly low in comparison to that of promethazine-HCl; i. e. about 50% of promethazine HCl was excreted within 3 hours, and 5 to 15 hours for that of promethazine pamoate. 4. The tissue concentration of promethazine after oral administration of promethazine pamoate in rabbit was steadily increased for 5 hours. However, promethazine HCl concentration reached to maximum 1 hour after administration, then decreased slowly. 5. A significant amount of promethazine was mainly distributed in spleen, kidney, lung, liver and heart in this order, rather than other organs, such as brain, and muscle. 6. In the toxicity test by using mouse, $LD_{50}$ for promethazine pamoate was 3,250 mg/kg, while $LD_{50}$ for promethazien HCl was 298mg/kg.

• Journal of the Korean Geotechnical Society
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• v.27 no.10
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• pp.5-12
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• 2011

This study was focused on the reactivity of furnace slag against cadmium to design the vertical drain method with reactive column for improving contaminated sea shore sediment. The kinetic sorption test was performed by changing the initial concentration and pH. Using pseudo-second-order model, the reactivity of furnace slag was quantitatively analyzed. Equilibrium removal amount ($q_e$) of furnace slag increased and rate constant ($k_2$) decreased with the increase of initial cadmium concentration. With the increase of pH, the equilibrium removal amount ($q_e$) and rate constant ($k_2$) increased in the same initial concentration. Required retention time was related to the inverse of the product of the equilibrium removal amount ($q_e$) multiplied by rate constant ($k_2$). The required retention time could be used to design the length of reactive column.

• KSBB Journal
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• v.11 no.2
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• pp.225-237
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• 1996

Intrinsic binding kinetics of of 125I-bovine serum albumin (125I-BSA) and immobilized monoclonal anti-BSA (MAb 9.1) were studied. Small non-porous polystyrene beads (0.5${\mu}$m diameter) were used as a solid support to minimize the mass transfer interference on rate measurements. We demonstrated both theoretically and experimentally that the binding reaction is kinetically controlled. Rate measurements show that the association reaction is of second order and the dissociation reaction is of first order. Between 4 and $37^{\circ}C$ the measured equilibrium constant agrees well with the equilibrium constant calculated from the rate measurements. The temperature effects on association are much greater than on dissociation; the activation energy for association is about 9Kca1/mole, as compared to 2Kca1/mole for dissociation. The use of small non-porous beads as a solid support in binding studies essentially avoids mass transfer limitations; such a system makes it possible to determine the intrinsic binding characteristics of any immobilized antibody on a solid surface.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.4
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• pp.397-401
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• 2006

A laboratory study was conducted to evaluate the kinetics of oxidation of trichloroethylene(TCE) in groundwater by potassium permanganate($KMnO_4$). Consumption of permanganate by TCE and aquifer material was also evaluated to obtain an appropriate injection rate of $KMnO_4$. TCE degradation by $KMnO_4$ in the absence of aquifer material was effective with a pseudo-first order rate constant, $k_{obs}=5.24{\times}10^{-3}s^{-1}\;at\;KMnO_4=500mg/L$. TCE oxidation by $KMnO_4$ was found to be second order reaction and the rate constant, $k=0.65{\pm}0.08M^{-1}s^{-1}$. Meanwhile, aquifer materials from the field site were actively reacted with permanganate, resulting in the significant consumption of $KMnO_4$. It might be attributed to the existence of metal oxides in the aquifer materials.

• Journal of the Korean Chemical Society
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• v.22 no.5
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• pp.281-288
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• 1978

Pseudo-first order rate constants $k_{obs}$ were determined for the reactions of naphthalenesulfonyl chlorides (1-NSC and 2-NSC) and anilines. The second order rate constant $k_2$ and third order catalytic $k_3$ were then determined from $k_{obs}$. For 1-NSC peri-hydrogen effect was observed. The large Brønsted ${\beta}$ and large negative slopes ${\rho}$ for the Hammett plots were obtained. These results with the unsually low values of activation parameters were consistent with the $S_AN$-elimination mechanism, but these can be equally well interpreted with the associative $S_N2$mechanism.

• Journal of the Korean Chemical Society
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• v.14 no.1
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• pp.85-89
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• 1970

The rate of the bromine-exchange reaction between gallium bromide and isopropyl bromide in nitrobenzene was measured at 19$^{\circ},\;25^{\circ}$ and 40$^{\circ}C$., using isopropyl bromide labelled with Br-82. The results indicated that the exchange reaction was second order with respect to gallium bromide and first order with respect to isopropyl bromide. The third-order rate constant determined at 19$^{\circ}C$. was 3.2 ${\times}10^{-2}l^2{\cdot}mole^{-2}sec^{-1}$. The activation energy, the enthalpy of activation and the entropy of activation for the exchange reaction were also determined.

• Membrane and Water Treatment
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• v.9 no.2
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• pp.79-85
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• 2018

In this work, batch adsorption of anionic dye acid green-25 (AG-25) from aqueous solution has been carried out at room temperature using anion exchange membrane (DF-120B) as a noval adsorbent. The effect of various experimental parameters such as contact time, membrane dosage, ionic strength and temperature on the adsorption of dye were investigated. Kinetic models namely pseudo-first-order, pseudo-second-order, Elovich, liquid film diffusion, Bangham and modified freundlich models were employed to evaluate the experimental data. Parameters like adsorption capacities, rate constant and related correlation coefficients for every model are calculated and discussed. It showed that adsorption of AG-25 onto DF-120B followed pseudo-first-order rate expression. Thermodynamic study indicates that adsorption of AG-25 onto DF-120B is an exothermic and spontaneous process.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.2
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• pp.230-236
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• 2018

Objective: Two ex vivo experiments were conducted to verify the effect of barley grain (Nusrat cultivar) treated with alkaline compounds (AC) including alum, ammonium, and sodium hydroxide or cation-exchanged organic extracts (OE) prepared from alfalfa hay, sugar beet pulp and Ulva Fasciata, on extent and digestion of starch. Methods: In the first study, the in vitro first order disappearance kinetic parameters of dry matter (DM), crude protein (CP) and starch were estimated using a non-linear model ($D_{(t)}=D_{(i)}{\cdot}e^{(-k_d{\cdot}time)}+I$, where: $D_{(t)}$ = potentially digestible residues at any time, $D_{(i)}$ = potentially digestible fraction at any time, $k_d$ = fractional rate constant of digestion (/h), I = indigestible fraction at any time). In the second experiment, the ruminal and post-ruminal disappearance of DM, CP, and starch were determined using in situ mobile nylon bag. Results: Barley grains treated with alum and alfalfa extract had a higher constant rate of starch digestion (0.11 and 0.09/h) than others. Barley grain treated with OE had a higher constant rate of CP digestion and that of treated with AC had a higher constant rate of starch digestion (0.08 and 0.11/h) compared with those of the other treatments. The indigestible fraction of starch treated with alum and sugar beet pulp extract was higher than that of the control group (0.24 and 0.25 vs 0.21). Barley grain treated with AC and OE had significant CP disappearance in the rumen, post-rumen and total tract, and also starch disappearance for post-rumen and total tract compared with the untreated (p<0.001). Conclusion: This study demonstrated that AC and OE might have positive effects on the starch degradation of the barley grain. In addition, treating barley grain with alum and sugar beet pulp extract could change the site and extend digestion of protein and starch.

• Bulletin of the Korean Chemical Society
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• v.17 no.3
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• pp.234-238
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• 1996

Second-order rate constants have been measured spectrophotometrically for the reaction of p-nitrophenyl acetate (PNPA) with morpholine, piperazine and piperidine in MeCN-H2O mixtures of varying compositions. The rate of the present aminolysis decreases upon additions of MeCN into H2O up to near 30-40 mole % MeCN and remains nearly constant upon further additions of MeCN. The reaction of PNPA with anionic nucleophiles, such as HO-, p-chlorophenoxide and butane-2,3-dione monoximate, has also exhibited two distinguishable reactivity zones. However, the reactivity trend for the anionic nucleophiles is quite different from the one obtained for the amine system, e.g. an initial rate decrease in the H2O-rich region followed by an increasing rate trend upon further additions of MeCN in the MeCN-rich region. The rate behaviors shown by the amine system in the MeCN-rich and by the anionic system in the H2O-rich region are unexpected based on the Hughes-Ingold rules. The present unusual rate trends have been attributed to changes in the solvent structure and pKa of the nucleophiles upon the addition of MeCN into H2O. The effect of solvent appears to be more significant for the TS than the GS, and the TS structure is considered to become tighter in the higher MeCN concentration.