• Bulletin of the Korean Chemical Society
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• 제21권6호
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• pp.653-655
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• 2000

• Bulletin of the Korean Chemical Society
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• 제31권8호
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• pp.2137-2138
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• 2010

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2008년도 제49회 학술심포지움 및 국제학술대회
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• pp.44.2-44.2
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• 2008

• 대한화학회지
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• 제8권1호
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• pp.15-19
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• 1964

Basicities of nine dimethylanilines have been determined in 50, 70, and 90 volume % ethanol, at $25^{\circ},\;30^{\circ},\;35^{\circ},\;and\;40^{\circ}C$. Temperature coefficients were found to be independent of solvent composition, while they showed a linear correlation with basicities of the compounds. Thermodynamic parameters obtained have been used in the discussion of substituent and solvent effects in conjunction with the general equation derived in the preceding papers.

• Macromolecular Research
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• 제8권2호
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• pp.53-58
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• 2000

Stabilities and structures of resorcinol formaldehyde resins (RF resins) and their dependence on solvent were studied by molecular mechanics and molecular dynamics. Dimers to decamers of the RF resins in the conditions of dielectric constant = 1.00, 21.01, 36.64, and 80.10 were calculated. The average distance between oxygen atoms in 1-hydroxyl groups of adjacent resorcinols of the resins became longer with increased dielectric constant of the environment. The number of intramolecular hydrogen bonds of the resins decreased by increasing the dielectric constant of the environment. The RF resin structure on the surface of fabric or steel cord was explained based on the present calculation.

• Bulletin of the Korean Chemical Society
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• 제2권2호
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• pp.41-45
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• 1981

For solvolyses of benzenesulfonylchlorides we determined transfer enthalpies of transition states, and solvent (TFE + EtOH) and substituent effects on rates. We have used the More O'Ferrall plots to show that transition states variation caused by solvent and substituent changes is consistent with an associative $S_N2$ mechanism for the nucleophilic substitution reaction of benzenesulfonylchlorides.

• Preventive Nutrition and Food Science
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• 제14권4호
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• pp.310-315
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• 2009

The partitioning behavior of the five printing ink solvents in nine lab-made cookies with various sugar and water content at 25${^{\circ}C}$ was studied to find out the presence and effects of interaction between the two ingredients on partitioning behavior in cookies. Solvents were ethyl acetate, hexane, isopropanol, methyl ethyl ketone and hexane. It was observed that the partition coefficient (the solvent concentration in food compared to that in air, Kp) decreased as sugar increased in all case and increased as water content increased for all compounds except toluene. Statistical analysis by the F-test method was used to determine the significance of sugar-water interactions, as well as other single factors on partitioning behavior of each solvent. Sugar content alone had no significant effects, but the crystallinity of sugar, as changed by water content, affected the partitioning behavior of the five solvents significantly. Parameter estimation for each significant factor by SAS program yielded a regression equation, which was used to predict the partitioning behavior in the finished cookie. Kp values from the regression equation could be determined more precisely by applying a correction term for the interaction between sugar and water to the Kp values of each ingredient after baking.

• 동의생리병리학회지
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• 제27권2호
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• pp.189-195
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• 2013

This study was designed to analyze the effects of methanol extracts and solvent fractions of the young branch of Prunus persica on scavenging activity of ROS, RNS and inhibiting activity of oxidative modification in human LDL induced by copper ion or free radical generator. The scavenging capacities of the fractions on DPPH radical, superoxide radical, nitric oxide and peroxynitrite were exhibited the highest in ethylacetate fraction, followed by butanol fraction. In the copper-induced LDL oxidative modification system, the highest antioxidant activity was revealed in ethylacetate fraction, and butanol fraction exhibited a similar activity. However, solvent fractions of the young branch of Prunus persica showed a relatively low antioxidant activity in the AAPH-mediated LDL oxidation. In addition, ethylacetate and butanol fractions also inhibited the copper-mediated LDL oxidation in the REM assay, which was comparable to that of the positive controls, including EDTA, ascorbic acid and BHT. Futhermore, a content of total phenolics in these two fractions was higher than that of the other fractions. These results indicated that ethylacetate and butanol fractions of the young branch of Prunus persica were useful for the prevention of the free radical- or metal ion-induced oxidative damages.

• Bulletin of the Korean Chemical Society
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• 제33권11호
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• pp.3657-3664
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• 2012

Reactions of 1-adamantylmethyl chloroformate ($1-AdCH_2OCOCl$, 1) and 1-adamantylmethyl fluoroformate ($1-AdCH_2OCOF$, 2) in hydroxylic solvents have been studied. Application of the extended Grunwald-Winstein (G-W) equation to solvolyses of 1 in a variety of pure and binary solvents indicates an addition-elimination pathway in the majority of the solvents except an ionization pathway in the solvents of relatively low nucleophilcity and high ionizing power. The solvolyses of 2 show an addition-elimination pathway in all of the mixed solvents. The leaving group effects ($k_F/k_{Cl}$), the kinetic solvent isotope effects (KSIEs, $k_{MeOH}/k_{MeOD}$), and the enthalpy and entropy of activation for the solvolyses of 1 and 2 were also calculated. The selectivity values (S) for each solvent composition are reported and discussed. These observations are compared with those previously reported for other alkyl haloformate esters.

• 한국산업보건학회지
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• 제11권1호
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• pp.17-25
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• 2001

The purpose of this study is to substitute water-based painting materials for the current solvent-based ones used in motor-repairing process to minimize the exposure of organic solvents to the painters. This study assessed the exposure of organic solvents to the painters using water-based and solvent-based painting materials and compared compositions, painting processes and the health hazards of the application of these alternative painting mate rials. The results of this study are as follows. 1. solvent-based painting materials used in motor-repairing process consist of various organic solvents, which consist primarily of toluene, xylene, ethyl benzene, ethyl methyl benzene, trimethyl benzene, ethyl acetate, butyl acetate, methyl isobutyl ketone, 2-ethoxy ethanol, 2-ethoxy ethyl acetate and toluene-2,4-diisocianate and the others. These organic solvents are known as health-hazardous substances. But water-based painting materials are high-solid, low-solvent one sand consist of such two organic solvents as 2-butoxy ethanol and 2-heptanone and the others. 2. The painters us ing solvent-based painting mate rials in motor-repairing process are exposed to various organic solvents which consist of toluene, xylene, ethyl acetate, butyl acetate, methyl isobutyl ketone, trimethyl benzene, 2-ethoxy ethanol, and 2-ethoxy ethyl acetate. But the painters using solvent-based ones are only exposed to 2-butoxy ethanol and 2-heptanone. 3. By using water-based painting materials in stead of solvent-based painting materials containing health-hazardous organic solvents, the exposure of such organic solvents in the painter's breathing zone can be largely prevented. 4. This study recommends water-based painting materials as substitutes for the current solvent-based ones used in motor-repairing process to minimize the exposure of organic solvents to the painters.