• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.11 no.1
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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.

• Membrane Journal
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• v.24 no.6
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• pp.484-490
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• 2014

To find out the feasibility of the separating/enriching esters from aqueous solution using FASs (Fluoloalkyl-silanes-coupling agent)-surface modified hydrophobic membrane, the solubility parameter of FASs was obtained and compared with those of esters and water. The value of the solubility parameter of FASs (${\delta}_t=16.9$) was almost same with those of esters (ethyl acetate ${\delta}_t=18.1$, propyl acetate ${\delta}_t=18.0$, ethyl propionate ${\delta}_t=17.9$, butyl acetate ${\delta}_t=17.4$, ethyl butyrate ${\delta}_t=17.0$). However, the calculated value of the solubility parameter of water was ${\delta}_t=47.8$, which was far from the value of the solubility parameter of FASs (${\delta}_t=16.9$). This means that the FASs-modified membrane has a much higher affinity to esters than water. The experimental results of permeation flux of esters used in this study showed that the order of permeation flux predicted by the solubility parameter was almost coincide with experimental results. It might be concluded that the solubility parameter may be applicable for a separating/enriching flavors from aqueous natural-flavor solution, in which esters are main components of natural flavors.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.30 no.4
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• pp.28-34
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• 1998

Polyvinyl acetate emulsion has been widely used as adhesives for wood and paper, paint additives and binders for fiber, leather, and other materials because it is an excellent adhesive with many advantages including low in toxicity risks and manufacturing cost. It is expected the consumption of polyvinyl acetate emulsion as adhesives will increase in cigarette industry as well as in paperboard coating industry. Recently the operation speed of the cigarette tip wrapper increased so substantially that improvement of the emulsion properties is required including good wet tack development, narrow and controlled particle size distribution, low viscosity, etc. In this study the effects of such polymerization conditions as the type and amount of emulsifier, internal or external plasticizing, and emulsification methods on the viscosity and particle size of polyvinyl acetate emulsions were examined. Results showed that polyvinyl alcohol with a high degree of hydrolysis and low molecular weight and nonionic surfactants are superior to anionic surfactant in improving adhesion and emulsion stability. They also tend to produce emulsions with smaller particle size. External plasticization with dipropylene glycol dibenzoate was more effective in improving flexibility than internal plasticization with butyl acrylate. Monomer emulsification under high shear was more effective in decreasing the particle size.

• The Korean Journal of Food And Nutrition
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• v.20 no.2
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• pp.240-244
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• 2007

In this study, we found that the methanolic extract of Areca catechu repressed expression of the tyrosinase gene in B16 mouse melanoma cells containing a tyrosinase promoter. Extract concentrations of 100 ${\mu}$g/ml and 500 ${\mu}$g/ml exhibited tyrosinase gene expression rates of aproximately 62% and 48%, respectively, compared to the control. The fraction layers consisting of ethyl acetate, butyl alcohol, and water showed repressive effects on the tyrosinase gene. In particular, the butyl alcohol fraction highly repressed at 100 ${\mu}$g/ml and 500 ${\mu}$g/ml. In the MTT assay, the methanolic extracts exhibited very low cytotoxicities at 1 ${\mu}$g/ml, 10 ${\mu}$g/ml, and 100 ${\mu}$g/ml.

• Toxicological Research
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• v.26 no.4
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• pp.293-300
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• 2010

tert-Butyl acetate (TBAc) is an organic solvent, which is commonly used in architectural coatings and industrial solvents. It has recently been exempted from the definition of a volatile organic compound (VOC) by the Air Resources Board (ARB). Since the use of TBAc as a substitute for other VOCs has increased, thus its potential risk in humans has also increased. However, its inhalation toxicity data in the literature are very limited. Hence, inhalation exposure to TBAc was carried out to investigate its toxic effects in this study. Adult male rats were exposed to TBAc for 4 h for 1 day by using a nose-only inhalation exposure chamber (low dose, $2370\;mg/m^3$ (500 ppm); high dose, $9482\;mg/m^3$ (2000 ppm)). Shamtreated control rats were exposed to clean air in the inhalation chamber for the same period. The animals were killed at 2, 7, and 15 days after exposure. At each time point, body weight measurement, bronchoalveolar lavage fluid (BALF) analysis, histopathological examination, and biochemical assay were performed. No treatment-related abnormal effects were observed in any group according to time course. Based on those findings, the median lethal concentration ($LC_{50}$) of TBAc was over $9482\;mg/m^3$ in this study. According to the MSDS, the 4 h $LC_{50}$ for TBAc for rats is over $2230\;mg/m^3$. We suggested that this value is changed and these findings may be applied in the risk assessment of TBAc which could be beneficial in a sub-acute study.

• Bulletin of the Korean Chemical Society
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• v.15 no.9
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• pp.791-795
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• 1994

1,3-Dimethyl and dipropyl ethers of p-t-butylcalix[4]arene and calix[4]arenes have been converted to the corresponding diesters, acetate and propionate, and their conformations are inferred based on the $^1H$ and $^{13}C$ NMR spectra. The presence of t-butyl groups is effective in maintaining the cone conformation on derivatization.

• Journal of Microbiology and Biotechnology
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• v.13 no.5
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• pp.647-650
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• 2003

In anhydrous organic solvents, the complexes formed between AOT (dodecylbenzene sulfuric acid sodium salt) and hemoproteins, such as hemoglobin, myoglobin, or cytochrome c, displayed remarkably higher activity than the hemoprotein powders to oxidize dibenzothiophene, a model compound of organic sulfurs contained in fossil fuels. In slightly hydrophobic organic solvents, such as ethyl acetate and butyl acetate, dibenzothiophene was completely oxidized catalytically by the cytochrome c-AOT complex with cumene hydroperoxide (${\alpha},{\alpha}-dimethylbenzyl$ hydroperoxide) as an oxidant. In highly hydrophobic organic solvents, such as decane and hexadecane, however, the activity of the cytochrome c-AOT complex decreased, presumably due to the aggregation of the hemoprotein-AOT complex in these solvents.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.76-82
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• 2012

A novel and efficient tetrahydrofuranyl ring opening method was developed using the highly reactive TFAT reagent in the presence of an acid scavenger, 2,6-di-tert-butyl-4-methylpyridine. Various acid sensitive groups are compatible with the reaction condition, making it generally applicable to many tetrahydrofuranyl steroids. Moreover, it is a synthetic equivalent of 'Marker degradation' affording an efficient synthesis of C17-OH rockogenin acetate.

• Archives of Pharmacal Research
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• v.16 no.4
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• pp.322-326
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• 1993

For the development of new antinflammatory and analgesic drugs, new 5-alkylthio (or sulfonyl) methyl-5-m-methoxyphenylhydantoin-3-acetic acid derivatives(alkyl; ethyl, propyl, butyl) were prepared. The 5,5 -disubstituted hydantoins which were used as starting materials, were prepared acording to Bucherer-Berg method. The reaction of ethyl chloroacelate with these compounds gave 3-acetate and the subsequent hydrolysis with dilute sodium hydroxide resulted in hydantoin 3-acetate and the subsequent hydrolysis with dilute sodium hydroxide resulted in hydantoin 3-acetic acid derivatives. Through the same procedure of equivalent hydroxide resulted in hydantoin 3-acetic acid derivatives. Through the same procedure of equivelent hydantions or the oxidation of 5-alkylthiohydantoin ocmpounds described above, 5-alkylsulfonylme-thyl-5-m-methoxyphenylhydantoin-30acetic acid derivatives were also synthesized.

• Elastomers and Composites
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• v.54 no.1
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• pp.35-39
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• 2019

Four different polymer compounds were prepared from four kinds of plasticizers, viz. di-2-ethylhexyl azelate (DOZ), di-2-ethylhexyl adipate (DOA), di-2-ethylhexyl sebacate (DOS), and di-2-butyl sebacate (DBS), for making cable sheaths for ships. Ethylene-vinyl acetate and ethylene-propylene-diene-copolymer as matrix polymers and ethylene-vinyl acetate grafted maleic anhydride as a coupling agent were compounded with a flame retardant, crosslinking agent, filler, and other additives, besides the plasticizer to obtain the polymer compounds. The polymer containing DOZ showed the highest MH and ${\Delta}T$ in the rheology test, while that containing DBS was found to have the lowest tensile strength and highest elongation because of low ${\Delta}T$. The four polymers showed similar values (31.7-31.9) for flame resistance, while the polymer containing DOZ showed the highest value for cold resistance.