• Bulletin of the Korean Chemical Society
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• v.24 no.7
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• pp.1041-1044
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• 2003

• Journal of the Korean Chemical Society
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• v.32 no.2
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• pp.113-121
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• 1988

The retention mechanism and separation of various aromatic sulfonic and carboxylic acids on reversed-phase liquid chromatographic column were studied in the mobile phase containing dodecyltrimethylammonium bromide (DTAB). The retention mechanism was found to be followed the ion-interaction model where the DTAB occupies a primary layer at the stationary phase while the sample anions and other co-anions in the system compete for forming the secondary layer. The capacity factors of samples were influenced by the several factors such as pH, concentration of various organic solvents, co-anions in the mobile phase and functional groups in sample molecules. Some mixtures of organic samples were attempted to separate under optimum condition.

• Journal of the Korean Graphic Arts Communication Society
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• v.21 no.1
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• pp.21-34
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• 2003

Acid amplifiers derived from a certain class of sulfonates suffer from autocatalytic decomposition in the presence of a strong acid to give corresponding sulfonic acid, which catalyze the composition of the parent sulfonates, leading to the liberation of more of the same sulfonic acids in an exponential manner. In this research we synthesized and evaluated 4-hydroxy-4'-(2-trifluoromethyl)benzenesulfonyloxy isopropylidene dicyclohexane (1), 4,4'-di-(2-trifluoromethyl)benzenesulfonyloxy isopropylidene dicyclohexane (2), 4-hydroxy-4'-(3-trifluoromethyl)benzenesulfonyloxy isopropylidene dicyclohexane (3) and 4,4-di-(3-trifluoromethyl)benzenesulfonyloxy isopropylidene dicyclohexane (4) as novel acid amplifiers with electron withdrawing group. These acid amplifiers (1-4) showed reasonable thermal stability for resist processing temeprature and exhibited higher photosensitivity compared to poly(tert-butyl methacrylate) film without acid amplifiers. Application of acid amplifiers to photofunctional materials, including photoresists, are described as a consequence of the combination of the acid amplifiers with photoacid generator.

• Journal of the Korean Chemical Society
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• v.38 no.9
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• pp.682-686
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• 1994

New synthetic method of aminophosphonic acids by the amination of organoboranes containing phosphorus was developed. Thus, the hydroboration of diethyl 2-propenylphosphonate, diethyl 2-methyl-2-propenyl-phosphonate, diethyl 3-butenylphosphonate with borane-THF, followed by amination of the resulting organoboranes with hydroxylamine-O-sulfonic acid gave diethyl 3-aminopropylphosphonate, diethyl 3-amino-2-methyl-2-propylphosphonate and diethyl 4-aminobutylphosphonate, respectively. 3-Aminopropylphosphonic acid and 4-aminobutylphosphonic, acid were obtained by the hydrolysis of the corresponding esters, respectively.

• Environmental Analysis Health and Toxicology
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• v.16 no.4
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• pp.223-226
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• 2001

Acetanilide is a High Production Volume Chemical, which is produced about 2,300 tons/year in Korea as of 1998 survey. Most is used as an intermediate for synthesis of pharmaceuticals and dyes. The chemical is one of seven chemicals, which are under the frame of OECD SIDS program sponsored by National Institute of Environmental Research of Korea. Regarding the information on the environmental fate. bioconcentration is one of important factor to estimate the environmental tranfer. However, measurement of bioconcentration needs high expense and time. For this reason, OECD recommends to use BCFWIN model to estimate bioconcentration of organic chemicals, BCFWIN estimates the bioconcentration factor (BCF) of an organic compound using the log octanol-water partition coefficient (Kow) of the compound. Structures are entered into BCFWIN through SMITES (Simplified Molecular Input Line Entry System) notations. The BCFWIN method classifies a compound as either ionic or non-ionic. ionic compounds include carboxylic acids, sulfonic acids and salts of sulfonic acids, and charged nitrogen compounds (nitrogen with a + 5 valence such as quaternary ammonium compounds). All other compounds are classified as non-ionic. In this study, bioaccumulation of acetanilide was estimated using BCFWIN model based on SMIIES notation, chemical name data and partition coefficient as one of environmental fate/distribution of the chemical elements.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.228-231
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• 2002

Itaconic acid has been produced during the cutivation of Aspergillus terreus DSMZ 5770 by using several starchs as carbon sources. The starchs were pretreated by partial hydrolysis with some acids at various pH conditions. The highest yield for the production of itaconic acid has been found when rice starch was pretreated by sulfonic acid at pH 2.5 and utilized for the cultivation. Using the results from shaker fermentation A. terreus has been cultivated in 2.5 L bioreactor for the production of itaconic acid and its on-line monitoring.

• Proceedings of the Membrane Society of Korea Conference
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• 1998.10a
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• pp.73-74
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• 1998

1. Introduction : We have researched to separate water effectively from aqueous pyridine solution. In our previous papers, we have proposed new separation mechanism, in-situ complex, which is different from solution-diffusion and accelerated transport by hydrogen bonding. We have adopted in-situ complex mechanism to membranes containing phosphoric acids as well as acrylic acid and sulfonic acid in copolymer for dehydration of pyridine.

• Applied Chemistry for Engineering
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• v.27 no.5
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• pp.490-494
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• 2016

This paper describes the very efficient and highly enantioselective ring opening of terminal epoxides with alkyl and arene sulfonic acid. The dinuclear chiral (salen) Co complexes bearing Lewis acids of Al, Ga and In catalyze the reaction enantioselectively in the presence of tetrabutylammonium chloride using tert-butyl methyl ether as a solvent. The variation of the anion of the tetra butyl ammonium salt has significant impact on the reactivity and selectivity of the asymmetric ring opening of phenyl glycidyl ether with p-toluenesulfonic acid. The order of reactivity and selectivity was found to be $Cl^-$ > $l^-$ > $Br^-$ > $OH^-$. Strong synergistic effects of the different Lewis acid centers of Co-Al, Co-Ga and Co-In complexes were observed in the catalytic process. The dinuclear chiral salen catalyst containing $AlCl_3$ was found to be most active and highly enantioselective (91% ee).

• Environmental Engineering Research
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• v.25 no.3
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• pp.281-289
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• 2020

Environmental fate of ionizable organic pollutants such as perfluoroalkyl acids (PFAAs) are of increasing interest but has not been well understood because of uncertain values for parameters related with atmospheric interphase partitioning behavior. In the present study, not only the values for air-water partition coefficient (K_AW) and dissociation constant (pKa) of PFAAs were induced by adjusting to in situ measurements of air-water distribution coefficient between vapor phase and rainwater but also gas-particle partition coefficients were also estimated using three-phase partitioning model of ionizable organic pollutants, in situ measurements of PFAAs in aerosol and air vapor phase, and obtained parameter values. The pKa values of PFAAs we obtained were close to the minimum values suggested in literature except for perfluorooctane sulfonic acids, and COSMOtherm-modeled K_AW values were assessed to more appropriate among suggested values. When applying parameter values we obtained, it was predicted that air particle-associated fate and transport of PFAAs could be negligible and PFAAs could distribute ubiquitously along the transection from urban to rural region by pH-dependent phase transfer in air. Our study is expected to have some implications in prediction of the environmental redistribution of other ionizable organic compounds.

• Preventive Nutrition and Food Science
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• v.13 no.3
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• pp.182-189
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• 2008

In this study, the effect of pH on the antioxidative activities of melanoidins formed as a result of the reaction between sugars, glucose (Glc) or fructose (Fru), and amino acids, L-asparagine (L-Asn) and D-asparagine (D-Asn) are examined. For this purpose, antioxidative activities were evaluated on the basis of reducing power, including ferric reducing/antioxidant power (FRAP) and free radical scavenging activity includes 1,1-diphenyl-2-picryl- hydrazil (DPPH) and 2,2'-azinobis(3-ethylbenothiazoline-6-sulfonic acid) diammonium salt (ABTS) and ferrous ion chelating activity. Ethylene diamine tetraacetate (EDTA) and trolox, a water-soluble analog of tocopherol, were used as reference antioxidant compounds. The antioxidative activities of the melanoidins at a pH of 7.0 were greater than those with a pHs of 4.0 and pH 10.0. Especially, it was found that the melanoidins formed from D-isomers are more effective antioxidants in different in vitro assays. The reducing power and chelating activity of the melanoidins formed from the Fru systems were higher than those of the melanoidins formed from the Glc systems. However, the ABTS radical scavenging activity of the melanoidins formed from the Glc systems were higher than those of the melanoidins formed from the Fru systems. In particular, the DPPH radical scavenging activity and the FRAP of the melanoidins showed different antioxidative activities according to pH level.