• Journal of the Korean Applied Science and Technology
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• v.31 no.2
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• pp.244-254
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• 2014

The interactions of 4-chlorobenzoic acid with the micellar system of various cationic, nonionic, and mixed surfactant systems were studied by the UV/Vis spectrophotometric method. The solubilization constants ($K_s$) of 4-chlorobenzoic acid into those micellar systems have been measured at various temperatures and various thermodynamic parameters for the solubilization of 4-chlorobenzoic acid have been calculated and analyzed from those changes. The results show that the values of ${\Delta}G^o_s$ are all negative within the measured temperature range and that the values of ${\Delta}H^o_s$ and ${\Delta}S^o_s$ are all positive. The effects of alkyl-group's length of surfactant molecules on the solubilization of 4-chlorobenzoic acid have been also measured. The values of $K_s$ were dependent simultaneously on the alkyl-group's length and the kind of head-group in surfactant molecules. From these changes we can postulate the solubilization site and the degree of interaction of 4-chlorobenzoic acid with the micellar systems.

• Journal of the Korean Applied Science and Technology
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• v.31 no.4
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• pp.612-622
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• 2014

In this study, we investigated the solubilization 4-chlorobenzoic acid in a wide range of temperature using a zwitterionic surfactant of lauryl sulfobetaine(LSB) and mixed surfactant systems. The effects of temperature and alkyl-group's length of surfactant molecule on the solubilization of 4-chlorobenzoic acid have been measured. The solubilization constants ($K_s$) were taken by the UV/Vis spectrophotometric method, plotting the total absorbance of the solution versus the surfactant concentration. The results show that the values of ${\Delta}G^o_s$ are all negative within the measured temperature range and decrease by increasing temperature, And also the measured values of ${\Delta}H^o_s$ and ${\Delta}S^o_s$ are all positive and increase by increasing temperature. The values of $K_s$ and thermodynamic parameters are simultaneously dependent on the temperature and the kinds of surfactant molecules. From the results we can postulate the solubilization site of 4-chlorobenzoic acid within the micelle.

• Journal of the Korean Chemical Society
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• v.50 no.5
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• pp.362-368
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• 2006

SH group modifying chemicals were used to characterize the eight cysteine residues of cabbage PLD. 5,5-dithiobis(2-nitrobenzoate)(DTNB) was used to titrate the SH group of cysteine residues . Based on the optical density at 412nm due to the reduced DTNB, 4 SH groups are found to be present in a native PLD while 8 SH groups in the denatured PLD whose tertiary structure was perturbed by 8M urea. The results imply that among the 8 cysteine residues of PLD, the half(4) are exposed on the surface whereas the other half are present at the interior of the enzyme tertiary structure. The PLD was inactivated by SH modifying reagents such as p-chloromercuribenzoate(PCMB), iodoacetate, iodoacetamide, and N-ethylmaleimide. At the addition of dithiothreitol(DTT) only the PCMB inhibited PLD activity was recovered reversibly. The micro-environment of the exposed SH group of cysteine residues was examined with various disulfide compounds with different functional groups and we found that anionic or neutral disulfides appear to be more effective than the positively charged cystamine for inactivating the PLD activity. The effect of redox state of cysteine residues on the PLD activity was further explored with H2O2. The oxidation of SH groups by H2O2 inhibited the PLD activity more than 70%, which was mostly recovered by DTT. From these results, we could confirm chemically that all the cysteine residues of PLD are present as in their reduced SH forms and the 4 SH groups exposed on the surface of the enzyme may play important roles in the regulation of PLD activity.

• Journal of the Korean Applied Science and Technology
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• v.30 no.4
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• pp.679-687
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• 2013

The critical micelle concentration (CMC) and counter-ion binding constant (B) of the pure cationic surfactants (DTAB, TTAB, CTAB), nonionic surfactants (Tween-20, Tween-40, Tween-80), and their mixed surfactants (TTAB/Tween-20, TTAB/Tween-40, TTAB/Tween-80) in aqueous solutions of 4-chlorobenzoic acid were determined by using the UV/Vis absorbance method and the conductivity method from 284 K to 312 K. Thermodynamic parameters (${\Delta}G^o{_m}$, ${\Delta}H^o{_m}$, and ${\Delta}S^o{_m}$), associated with the micelle formation of those surfactant systems, have been estimated from the dependence of CMC and B values on the temperature and carbon length of surfactant molecules. The calculated values of ${\Delta}G^o{_m}$ are all negative within the measured range but the values of ${\Delta}H^o{_m}$ and ${\Delta}S^o{_m}$ are positive or negative, depending on the length of the carbon chain and surfactant.

• Polymer(Korea)
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• v.25 no.5
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• pp.635-641
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• 2001

$\beta$-Cyclodextrine/benzoic acid complex was prepared and reacted with cyanuric chloride (2,4,6-trichloro-1,3,5-triazine). Identification of complex formation and reaction was checked by FT-IR, UV-Vis, and EDX. By reacting this material with cotton fiber, the deodourant fiber was prepared. The deodourizing property was evaluated by the concentration changes of aqueous ammonia solution after flowing ammonia gas through the column titled with deodourant fiber prepared. The deodourizing property was increased with an increase of concentration of $\beta$-cyclodextrine unit in the fiber. In the case of $\beta$-cyclodextrine/benzoic acid complex, the deodourzing property was much increased, comparing with the $\beta$-cyclodextrine only. It was considered to be the binding of aamonia gas caused by benzoic acid in the complex.

• Polymer(Korea)
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• v.38 no.6
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• pp.791-800
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• 2014

4-Chlorobenzoyl (CB) group-attached multi-walled carbon nanotube (c-MWNT) was prepared via a direct Friedel-Crafts acylation of MWNT with 4-chlorobenzoic acid (CBA) in a $P_2O_5$/poly(phosphoric acid) medium. c-MWNT with a maximum chlorine content of 5.3 wt% (CB group content of 20.9 wt%) was obtained by controlling the amount of CBA during the reaction. Using a self-condensation polymerization of 4-chlorobenzenethiol (CBT) to poly(phenylene sulfide) (PPS), MWNT-g-PPS was prepared by adding c-MWNT of chlorine content of 5.3 wt% during the self-polymerization of CBT and removing homo PPS after polymerization in order to increase the interfacial interaction between PPS and MWNT. Thermal and surface properties of the MWNT-g-PPS were characterized. The results showed that PPS was formed on the surface of c-MWNT by the condensation of c-MWNT and CBT.

• The Korean Journal of Pesticide Science
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• v.9 no.3
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• pp.274-277
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• 2005

Fenpyroximate was prepared by Williamson synthesis of 4-hydroxyimino-5-phenoxypyrazole and t-butyl 4-bromomethyl benzoate, while an efficient method for the synthesis of t-butyl benzoate still remains a challenging problem. We have found that t-butyl benzoate could be prepared from benzoic acid by the sulfuric acid-catalyzed reaction with isobutene via in situ generation from t-butanol. It has been proven that this process is more convenient for the preparation of t-butyl 4-bromobenzoate, thus allows a facile entry to fenpyroximate.

• Polymer(Korea)
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• v.26 no.2
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• pp.200-208
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• 2002

Two-component polyurethane flame-retardant coatings were prepared by blending trichloro lactone modified polyesters (TAPTS) and isocyanate, Desmodur IL. Polycondensation reaction of trichlorobenzoic acid (TBA) as a flame-retardant component, and adipic acid with trimethylolpropane, polycaprolactone 0201, and 1,4-butanediol gave the corresponding TAPTs. The content of TBA was adjusted from 10 to 30 wt% in our experiment. It was found that various properties of these new flame-retardant coatings were comparable to other non-flame-retardant coatings. We also carried out three different tests for the measurement of flammability of flame -retardant coatings. The results of vertical burning test for the coatings containing more than 20 wt% of TBA were determined as 'no burn'. The results of flammability test for the coatings with 20 and 30 wt% of TBA contents indicated the limiting oxygen index (LOI) values of 25% and 27% respectively, which implied relatively good flame retardancy. They also showed the char length of 3.6-5.2 cm according to $45^{\circ}$ Meckel burner test, which can be classified as the first grade flame-retardant coatings.

• Applied Chemistry for Engineering
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• v.29 no.4
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• pp.432-439
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• 2018

Metal catalysts such as Fe, Co, Mn, and Pd supported on the activated carbon (AC) were prepared to improve functional groups for the chemical adsorption and catalytic ozonation. Following ascending orders of the phenol decomposition rate, dissolved ozone decomposition ratio and TOC (total organic carbon) removal from experimental results of advanced oxidation process (AOP) were observed: Fe-AC < AC < Co-AC < Mn-AC < Pd-AC. BET analysis results showed that the physical properties of the metal impregnated activated carbon had no effect on the catalytic ozonation, and the catalytic effect was dependent on the kind of impregnated metal. The ratio of the formed concentration of OH radical to that of ozone (RCT) was measured by using the decomposition outcome of p-chlorobenzoic acid, a probe compound that reacts rapidly with OH radical but slowly with ozone. The measured values of RCT were $5.48{\times}10^{-9}$ and $1.47{\times}10^{-8}$ for the ozone alone and activated carbon processes, respectively, and $2.13{\times}10^{-9}$, $1.51{\times}10^{-8}$, $4.77{\times}10^{-8}$, and $5.58{\times}10^{-8}$ for Fe-AC, Co-AC, Mn-AC, and Pd-AC processes, respectively.

• Journal of the Korean Chemical Society
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• v.56 no.5
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• pp.556-562
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• 2012

The critical micelle concentration (CMC) and the counter-ion binding constant (B) for the mixed micellizations of TTAB (tetradecyltrimethylammonium bromide) with other surfactants (DTAB, CTAB, Tween-20, Tween-40, and Tween-80) in aqueous solution of 4-chlorobenzoic acid (0.5 mM) at $25^{\circ}C$ were determined as a function of ${\alpha}_1$ (the overall mole fraction of TTAB) by using the spectrophotometric method and the conductivity method. Various thermodynamic parameters ($X_i$, ${\gamma}_i$, $C_i$, $a_i^M$, ${\beta}$, and ${\Delta}H_{mix}$) were calculated for each mixed surfactant system and compared with the other mixed surfactant systems by means of the equations derived from the nonideal mixed micellar model. The results show that TTAB/DTAB mixed system has a great positive deviation from the ideal mixed micellar model and the other mixed systems have great negative deviations from the ideal mixed model.