• Journal of Microbiology
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• v.35 no.3
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• pp.188-192
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• 1997

The strain of S-47 degrading 4-chlorobenzoic acid (4CBA) was isolated from Ulsan chemical industrial complex by enrichment cultivation with 1 mM 4CBA. The strain was Gram-negative rod and grew optimally at 30.deg.C and pH 7 under aerobic condition, so that the organism was identified as a species of Pseudomonas. Pseudomonas sp. S-47 degraded 4-chlorobenzoic acid to produce a yellow-colored meta-cleavage product, which was confirmed to be 5-chloro-2-hydroxymuconic semialdehyde (5C-2HMS) by UV-visible spectrophotometry. 5C-3HMS was proved trometry. This means that Pseudomonas sp. S-47 degraded 4CBA via 4-chlorocatechol to 5C-2HMS by meta-cleavage reaction and then to 5C-2HMA by 5C-2HMS dehydrogenase.

• Journal of the Korean Chemical Society
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• v.43 no.6
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• pp.628-635
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• 1999

Direct preparative method of 2,6-diformyl-p-cresol and 2-hydroxy-3-hydroxy-5-methylbenzaldehyde from 2,6-bis(hydroxymethyl)-4-methylphenol using activated $Mn(IV)O_2$ was described. Hexadentate compartmental Iigands, $H_4L[A]\;and\; H_4L[B]$ were prepared by condensation reactions of 2-hydroxy-3-hydroxy methyl-5-methylbenzaldehyde with ethylenediamine and 1,3-diaminopropane respectively. By the reaction of macrocycle($H_4[20]DOTA$) with Ln(III) nitrate {Ln(III)=Pr, Sm, Cd, Dy }, discrete mononuclear Ln(III) complexes of the type $[Ln(H_2[20]DOTA)(ClO_4)(H_2O)]\;{\cdot}\;3H_2O$ were synthesized in the solid state. $[Ln([20]DOTA)(NO_3)(H_2O)](NO_3)_2\;{\cdot}\;xH_2O$ was placed in methanol for 2 days, and $[Ln([20]DOTA)(NO_3)(CH_3OH)]^{2+}$ was formed. The equilibrium constants(K) for the substitution of coordinated $CH_3OH$ in the Ln-[20]DOTA complexes by various auxiliary ligand, $L_a$(=salicylic acid, p-chlorobenzoic acid, benzoic acid, acetic acid, 4-bromophenol) were determined spectroscopically at 25$^{\circ}C$ and 0.1M $NaClO_4$. The K values calculated were in the order of salicylic acid > p-chlorobenzoic acid > benzoic acid > acetic acid > 4-bromophenol, while pKa of auxiliary ligands was in the opposite trend.

• Journal of the Korean Chemical Society
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• v.59 no.5
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• pp.379-386
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• 2015

The solubilization of p-chlorobenzoic acid in aqueous solutions of pure cationic, nonionic, amphoteric, and their mixed surfactant systems have been measured by the UV-Vis spectrophotometric method. The effects of hydrophobic tail-group with different chain length and the hydrophilic head-group on the solubilization of p-chlorobenzoic acid have been studied and also thermodynamic parameters have been calculated from the dependence of K_s values on the temperature. The results show that the values of ΔG^o for the solubilization by all surfactant systems are negative and the values of ΔH^o and ΔS^o are all positive.

• Korean Journal of Microbiology
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• v.28 no.1
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• pp.41-46
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• 1990

A bacterial isolate of DJ-12 capable of degrading 4-chlorobenzoic acid (4CBA) as well as 4-chlorobiphenyl (4CB) was used in this study. Its biodegradability of 4CBA was tested and the location of the genes coding for degradation of 4CBA was investigated by the nethod of in vivo cloning. The genes were found to be existed in the plasmid of pDJ121 which is about 65kb in size and which has 9, 11, 10, and 19 restriction sites for EcoRI, HindIII, SalI, and PstI, respectively. The hybrid plasmid of pDK450 was constructed by ligation of the EcoRI fragments of pDJ121 with pKT230 as a vector. In the recombinant cells selected through transformation of the hybrid vector into Pseudomonas putida KT2440, the 4CBA-degrading genes of DJ-12 were proved to be cloned and expressed in the Pseudomonas sp.

• Applied Biological Chemistry
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• v.30 no.1
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• pp.40-45
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• 1987

Degradation of polychlorinated biphenyls(PCBs) and organochlorine pesticides by Alcaligenes aquamarinus has been studied and also degradation product of PCB-42 was investigated by TLC and GC. The less chlorinated members of PCBs such as Aroclor 1016 was degraded readily by the strain and rates of the microbial degradation of several organochlorine pesticides were found to decrease in the order of p,p'-DDT, r-BHC and Thiolix. Approximately 40 percent of PCB-42 was degraded when incubated with non-autoclaved soil for 25 days at $25^{\circ}C$. The yellow compound from PCB-42 was tentatively identified as p-chlorobenzoic acid.

• Journal of Korean Society of Forest Science
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• v.78 no.2
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• pp.198-208
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• 1989

Cell suspension cultures for Salix koreensis was well established at the supplements of 2, 4-D with cytokinin particulary the combination of 1.0 mg/l 2, 4-D with 0.1 mg/l of zeatin. These combined rates of phytohormones are also effective to callus induction from S, koreensis leaf and its multiplication. Cultured media exhibited the great inhibitory effect on the germination of rice, barnyard grass and lettuce seeds, indicating the presence of biologically active substances in media. Several phenolic compounds such as pyrogallol, sinapic acid, cinnamic acid, tannic + gallic and p-chlorobenzoic acid were detected in the cell suspension culture. The inhibitory effect exhibited by cultured media may be partly attributed to these phenalic compounds.

• 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.

• 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.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.10
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• pp.1039-1046
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• 2008

The combining process of UV irradiation and H$_2$O$_2$ was used to investigate characteristics of cefaclor decomposition in the aquatic environment. The separate mixing tank was used to minimize the decreasing effective of contact area caused by sampling. Four baffles were installed inside the UV reactor for the complete mixing of the sample and outside of the reactor was wrapped with aluminum foil to protect the emission of photon energy. Production of OH radical was measured using pCBA(p-Chlorobenzoic acid) indirectly and rate constants were withdrawn pseudo-frist order reaction. Optimum condition for the maximum production of OH radical was found to be pH 3, hydrogen peroxide of 5 mmol/L and recirculation rate of 400 mL/min. Pseudo-frist order reaction rate constant was 0.1051 min$^{-1}$. In the optimum condition, cefaclor was completely decomposed within 40 min and rate constant was 0.093 min$^{-1}$. Decomposition by OH radical producted intermediate anions such as chloride, nitrate, sulfite and acetic acid and phenylglycine. After 6 hr most cefaclor was decomposed by UV/H$_2$O$_2$ process and converted to CO$_2$ and H$_2$O, resulting of operation in the decrease of TOC and acetic acid and the disappearance of phenylglycine.

• Korean Journal of Weed Science
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• v.8 no.2
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• pp.169-175
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• 1988

This experiment was conducted to determine the presence of allelopathic substance in Portulaca oleracea L. Water and methanol extract from P. oleracea markedly inhibited the germination of lettuce, rice, raddish etc., indicating the presence of biological substances. The biochemical substances such as ferulic, p-coumaric, salicylic, vanillic, p-hydroxybenzoic acid etc., belonging to phenolic compounds were detected in a large amount, which may be responsible for exhibiting inhibitory effects. Various phenolic compounds were detected from different samples such as freshly, dried plants, seeds and callus. The highest amount of tannic and gallic acids were detected in dried samples of P. oleracea, the highest grantity of salicylic and vanillic acids in fresh samples, the largest amount of ferulic acid in seed sample, the highest amount of p-hydroxybenzoic and p-chlorobenzoic acids in callus. Linolenic acid was presented in amount of 9.203 mg/g in dried plant of P. oleracea as one of the major fatty acids and oxalic acid presented 27.941 mg/g as one of the major organic acids. These compounds seemed to be related to inhibitory effect of P. oleracea which needs further study.