• 한국염색가공학회지
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• 제15권6호
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• pp.55-62
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• 2003

Wool fabrics were dyed with the aqueous solution of C. I. Red Acid 114 mixed with methanol dissolving three kinds of barely water soluble ketones, acetophenone, 2-pentanone, and 3-pentanone. The steric hinderance and the orientation of the bigger hydrophobic part of the solvated dye molecules to the fiber slowed down the dying rate, however, loosening the wool molecule, say a little swelling, disaggeregating the dye molecules, and attaining the higher dye concentration on the fiber surface by the added solvents increased the amount of dye on the fabric. The higher concentration or/and the higher dyeing temperature helped loosen fiber molecules and made it easier for the solvated dye molecules to penetrate into the inside of the fiber. Acetophenone, the most influential solvent used, showed that the ability to loosen fiber molecules was the most important of all the three positive solvent actions mentioned above. The considered mechanism provided before reflected the fact that the dye uptake on the fabric dyed with the solvents included, except for 0.034M and 0.051M of acetophenone, was even lower than that without any solvents at $50^\circ{C}$, but all the solvents added to the dye bath increased the dye uptake on the fiber at $70^\circ{C}$.

• 한국염색가공학회지
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• 제4권3호
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• pp.82-90
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• 1992

To optimize the foam dyeing procedures for polyester and polyester/nylon blended non-woven fabrics, the effects of organic solvents and surfactants were investigated by measuring the foam heights and surface tensions of the foam dyeing solution. The results of the experiments can be summarized as follows: 1) Organic solvents and surfactants (sodium lauryl sulphate: SLS) solution lower the surface tension (ST) of the water, but ST lowering rate of SLS solution is greater than that of solvents. For a 0.25% SLS solution, the minimum surface tension was 30.3 dyne/cm, which is nearly the same value for organic solvents. 2) For 0.25% SLS solutions, additional adding of a 4.0% organic solvent makes the foam height (FH) be its maximum. 3) At 0.6 g/ι dye concentration, incorporation of 0.4% SLS makes the surface tension of the foam solution be its minimum. The foam height did not show any trend due to the dye type. 4) The effect of foam stabilizers (sodium alginate (Alg-Na) and hydroxy ethyl cellulose (HEC)) were also investigated. The foam height of the foaming solution with HEC was greater than that with Alg-Na. The foam stability of the foaming solution with Alg-Na was better than that with HEC.

• 한국식품영양과학회지
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• 제27권3호
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• pp.406-412
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• 1998

Such extraction conditions as the kinds of solvent, extracting temperature, extracting time, ratio of material to solvent and particle size of material, were studied to maximize the extraction of oleoresin from chipi. Larger amount of soluble solids were extracted from seeds with nonpolar solvents (hexane, pentane, ether) for extraction, because the seeds contained large amount of crude fats and monoterpene(limonene) volatile compounds. Larger amount of soluble solids were extracted from peel with polar solvents(methanol, ethanol) of extraction because of large amount of water soluble colors, sugars and oxygenated terpene bolatile compounds in the peel. The application of the solvents in intermediate polarity (dichloromethane, acetone) resulted in more effective extraction of soluble solid and volatile compounds. Expecially, dichloromethane was an excellent solvent in extraction of volatile compounds. In the concern of volatile compound recovery yield, the optimum extraction conditions, such as temperature, time, mixing ratio of material to dichloromethane and mean particle size, were $25^{\circ}C$, 10min, 1:10(w/v), 355~250${\mu}{\textrm}{m}$ for chopi peels and 3$0^{\circ}C$, 10min, 1:8(w/v), 355~250${\mu}{\textrm}{m}$ for chopi seeds, respectively.

• 대한화학회지
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• 제17권3호
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• pp.207-212
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• 1973

毛細灌法을 利用하여 여러가지 混合溶媒系(dioxane-n-butanol, dioxane-sec-butanol, dioxane-ethyleneglycol, dioxane-kerosene)중에서 polyvinylacetate의 희박용액을 機械的으로 切斷하여 그 결과로 얻어진 平均切斷速度定數(k) 및 極限重合度(g)를 moleculare dimension이 동일한 조건하에서 比較검토하였다. 그 결과 k보다는 g의 값이 사용하는 solvent의 종류에 따라 크게 영향을 받음을 알았으며 이에 關하여 考察하였다.

• 한국산업보건학회지
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• 제8권1호
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• pp.88-94
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• 1998

Korea has been rapidly industrialized during the past 35 years. During this period, Korea has emphasized only production and workers health has been ignored. Workers are most frequently exposed to organic vapors, such as thinners. This study was performed to evaluate worker exposures to organic solvents by size and type of industry. Results are summarized below. Workers were exposed to mixtures of toluene, xylenes, trichloroethylene, n-hexane, acetone, methanol, n-butanol, n-butyl acetate, and MIBK. Considering additive effects of the compounds, exposure indices (EIs) were calculated. It was found that worker exposures to organic solvents were highest in small industries and lowest in large industries. During a day shift, the highest exposure was indicated 3 - 5 p.m. in the afternoon. Workers in small industries had potential exposures exceeding permissible exposure limits for organic solvents. Local exhuast systems were inappropriate and respiratory protective devices were not supplied to the workers in small industries. Neither program for safe use and storage of toxic materials nor program for respirators was found in any of the plants investigated. Based on the results of the study, workers of small scale industries should be considered first in industrial health.

• 한국환경보건학회지
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• 제24권2호
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• pp.80-87
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• 1998

To evaluate the effects on health by exposure to low dose organic solvents, the author analyzed the air concentration of mixed organic solvents (toluene, xylene, butylacetate) at worker's breathing zone during painting, some laboratory findings of blood (WBC, RBC, Hb, Hct, SGOT, SGPT, TC, TG, HDL-C, LDL-C, IgG, IgM, IgA and IgE) and urine (hippuric acid, urinary protein, urobilinogen), surveyed the subjective symptoms those were obtained from 35 male workers exposed to mixed organic solvents, and 25 male workers not exposed to organic solvents who worked in car repair workshops in Taejon area from December 1, 1995, to February 29, 1996. The results were as follows: 1. The mean concentration of urinary hippuric acid of car painting worker group (organic solvent exposure group) was 0.76$\pm$ 0.21 g/l, which is significantly higher than that of non-exposed group. 2. In hematologic findings, the values of RBC, TC, LDL-C, IgG and IgE in the exposure group were significantly lower than those of the nonexposed group, but SGOT and SGPT in the exposure group were significantly higher than those of the non-exposed group. 3. Urinary hippuric acid levels showed positively correlated with toluene, urobilinogen and HDL-C levels, but those were negatively correlated with RBC, LDL-C, IgM levels. 4. Rates of the subjective symptoms such as "dizziness", "appetite loss", "weight loss", "palpitation", "chest tightness", "sore throat and eye discomfort", "tingling sense and acrodynia", "illusion or hallucination" and "decreaased motor power" were significantly higher in the exposure group than those of the non-exposed group.

• 한국초전도ㆍ저온공학회논문지
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• 제20권3호
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• pp.11-14
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• 2018

$MgB_2$ superconducting properties have been investigated with the surface-treated boron powders using the chemical solvents. Various solvents were used such as acetone, ethanol, methanol, and water to possibly modify the surface condition of raw boron powders as received. This treatment was done at an argon gas environment inside the glove box to reduce the further contamination during and after chemical treatments. It was found that $T_c$ values were increased to 37.58-37.73 K from the pure sample of 37.50 K when they were treated in inert environment. High- fields $J_c$ at both 5 & 20 K was all increased regardless of any kinds of chemical treatments mentioned above. It is also noted that the $J_c$ at low-fields were increased in the order of solvents: ethanol > acetone > pure $MgB_2$ = methanol > water.

• BMB Reports
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• 제36권4호
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• pp.367-372
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• 2003

The stability of four hemoglobins (Hb) in dimer forms (low concentration) were investigated by the kinetics of denaturation. The rate constants of denaturation were obtained by variation of 280 nm absorption versus time in 10 mM Tris-HCl, 10 mM EDTA, pH 8.0 at $45^{\circ}C$ in the absence and presence of 0.5 M ethanol, dimethyl sulfoxide (DMSO), formamide, and glycerol. The results show the trend of rate constants in different co-solvents in the following order: chicken hemolysate < human hemolysate and chicken Hb D < chicken Hb A. The buried surface area was calculated for Hb samples in the absence of cosolvents. Accordingly, the trend points out that: chicken Hb D > chicken Hb A > human Hb A. These results suggest that both chicken hemolysate and chicken Hb D are relatively more stable than human and chicken Hb A, respectively. However, the denaturation rate constants of Hb in different co-solvents have designated the following order: ethanol > DMSO > formamide > glycerol. As a matter of fact, this phenomenon is an indication of an increase in the denaturation capacity (DC) and hydrophobicity, and a decrease in the surface tension of the solution in the preceding co-solvents.

• 한국식품과학회지
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• 제17권6호
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• pp.490-494
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• 1985

물에 녹지않는 기질을 사용할 수 있고, 다시 효소를 회수하여 다음에 사용하고자 할때 효소와 기질등 과의 분리등 여러 가지 장점이 있는 2상계(이상계(二相界))를 사용하여 Rhizopus arrhizus의 리파제에 의한 에스테르 교환반응을 위한 기본 실험으로써 물에 녹지 않는 각종 유기용매 중에서 이 반응을 위한 가장 좋은 유기용매를 고르고자 유기용매가 리파제의 안정도와 활성도에 미치는 영향을 보았다. 이실험에서 사용된 유기용매는 n-hexane, n-heptane, n-octane, isooctane, cyclohexane등 5개의 탄화수소와 doethylether, diisopropylether, di-n-butylether등 3개의 에테르이다. 실험 결과 diiso-propylether와 isooctane 이 다른 유기용매에 비해 월등히 2상계를 이용한 에스테르 교환 반응에 좋은 용매임을 알았다.

• Bulletin of the Korean Chemical Society
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• 제34권2호
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• pp.615-621
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• 2013

Solvolyses of isobutyl chloroformate (4) in 43 binary solvent mixtures including highly aqueous media, water, $D_2O$, $CH_3OD$, 2,2,2-trifluoroethanol (TFE) as well as aqueous 1,1,1,3,3,3-hexafluoro-isopropanol (HFIP) solvents were performed at $45^{\circ}C$, in order to further investigate the recent results of D'Souza, M. $J^1$. et al.; solvolyses of 4 are found to be consistent with the proposed mechanism ($Ad_E$). The variety of solvent systems was extended to comprise highly ionizing power solvent media ($Y_{Cl}$ > 2.7 excepted for aqueous fluorinated solvents and pure TFE solvent) to investigate whether a mechanistic change occurs as solvent compositions are varied. However, in case of 18-solvent ranges having aqueous fluorinated solvent systems (TFE-$H_2O$ and HFIP-$H_2O$) and/or having $Y_{Cl}$ > 2.7 solvent systems, the solvent effect on reactivity for those of 4 are evaluated by the multiple regression analysis as competition with $S_N2$ - type mechanism. And in pure TFE and 97 w/w % HFIP solvents with high $Y_{Cl}$ and weak $N_T$, these solvolyses are understood as reactions which proceed through an ionization ($S_N1$) pathway.