• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.2
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• pp.28-33
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• 2016

This study was conducted to investigate the effects of deep eutectic solvent (DES) treatment on properties of TMP fibers and handsheets. DES was prepared by mixing of lactic acid and betaine (L and B), and the molar ratio of these two components mixtures was controlled to 2:1 (L:B=2:1) and 5:1 (L:B=5:1). As results, lignin was partly extracted from the TMP fibers. Especially, the delignification of TMP samples was promoted according to the increase of the molar ratio of lactic acid. Except for tear index, both tensile index and burst index of handsheets were increased when higher molar ratio of lactic acid was mixed for DES preparation. However, the LB DES treatment of TMP fibers didn't give any effect on the optical properties of TMP handsheets. The plausibility of TMP fiber was to be enhanced by LB DES treatment.

• Elastomers and Composites
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• v.24 no.2
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• pp.110-121
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• 1989

The radical initiated graft copolymerization of acrylonitrile(AN) and 4-chlorostyrene(4-Clst) onto ethylene-propylene-diene terpolymer(EPDM) rubber was investigated under various conditions. Graft copolymer(AU-EPDM-4-Clst) was isolated b: selective solvent extraction and identified by using IR spectroscopy. The percent grafting is determined as a function of solvent, reaction time, and monomer mole ratio. Percent grafting decreased in the order of tetrahydrofuran(THF)>THF/ethyl acetate(EA)(1 : 1)>cyclohexane/EA(1 : 1)>n-hexane/EA(1 : 1). Grafting increased continuously with increasing the reaction time up to 40 hr, beyond which the grafting levelled off. It was observed that percent grafting increased as increasing [4-Clst]/[AN] mole ratio, but decreased when [4-Clst]/[AN] mole ratio was higher than 1.60. The light resistance of graft copolymer(AN-EPDM-4-Clst) was better than that of ABS.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.4
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• pp.548-552
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• 2001

This study was designed to find optimum conditions of four different factors (ratio of solvent to cholesterol-$\beta$-cyclodextrin complex, mixing speed, mixing temperature, and mixing time) for cholesterol dissociation in cream. Using the ratio of 6 to 1 (solvent to the complex) showed the highest cholesterol dissociation rate (82.50%) when mixed at 100 rpm at $50^{\circ}C$ for 1 h. Mixing speed did not significantly affect the cholesterol dissociation. Also, mixing time appeared to be insignificant. The optimum mixing temperature was $50^{\circ}C$ and mixing at $40^{\circ}C$ resulted in a significantly lower rate, compared with that at $50^{\circ}C$. In a subsequent experiment, using recycled $\beta$-cyclodextrin only showed 75.07% of cholesterol removal in cream, while the mixture of recycled to unused $\beta$-CD with the ratio of 6 to 4 increased cholesterol removal to 95.59%, which is highly close to that of 100% unused $\beta$-CD.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.3
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• pp.338-345
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• 2003

Response surface methodology was used for monitoring changes in phenolic compounds properties of Rubi Fructus extract depening on extraction conditons. The three independent variables (extraction conditions) were ratio of solvent to sample content (5, 10, 15 mL/g), ethanol concentration (20, 40, 60%) and extraction time (2, 4, 6 hr). It was anticipated that each of the five dependent Y variables (responses) would be affected by the three independent variables. The dependent responses were total yield, total phenolics content, electron donating ability, antioxidant ability and nitrite-scavenging ability (pH 1.2, 3.0, 4.2, 6.0). Total yield, total phenolics content, electron donating ability and antioxidant ability were affected by ratio of solvent to sample content. Nitrite- scavenging ability at pH 1.2 and pH 6.0 was affected by ethanol concentration, while it was affected by extraction time at pH 3.0 and pH 4.2. The optimum extraction conditions for total yield were 14.16 mL/g ratio of solvent to sample content,39.08% ethanol concentration and 2.99 hr extraction time. The maximum total phenolics content of extracts were shown at 14.06 mL/g ratio of solvent to sample content, 35.51% ethanol concentration and 3.15 hr extraction time.

• Food Science and Preservation
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• v.15 no.1
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• pp.111-117
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• 2008

As part of studies on functional food development from the acorn (Quercus acutissima CARRUTHERS), this study investigated the antioxidant properties of the acorn using response surface methodology. Optimal extraction conditions were established by monitoring total phenol levels, electron donating ability, antioxidant ability and nitrite-scavenging action using response surface analysis under a central composite design. The extraction temperature varied in the $30-70^{\circ}C$, the extraction time between 1-5 h, and the solvent ratio was in the interval 5-25mL/g of sample. Extracted total phenols were highest at $57.91^{\circ}C$, 4.08 h, and 22.39 mL/g. This extraction was influenced by solvent ratio, but not by extraction time or temperature. Electron donating ability was found to be highest at $60.37^{\circ}C$, 2.85h, and 6.47 mL/g. The highest antioxidant level was 2.09 AI at $37.11^{\circ}C$, 1.67 h, and 18.84 mL/g, and this value was greatly influenced by all of extraction temperature, extraction time, and solvent ratio. Nitrite-scavenging ability was found to be highest at $47.07^{\circ}C$, 1.24h, and 19.55mL/g. Changes in nitrite-scavenging ability were most influenced by solvent ratio, followed by extraction temperature, but no influence of extraction time within the range tested was found.

• Korean Journal of Food Science and Technology
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• v.24 no.2
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• pp.137-141
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• 1992

To investigate some factors on oleoresin extraction from red pepper, the content of yield, capsanthin and capsaicin in oleoresin extracted under various factors such as solvent, variety of materials, extraction time and temperature, storage condition of dried red pepper and its parts, particle size of raw material powder and the ratios of red pepper powder to extraction solvent were investigated. Ethyl alcohol and ethylene dichloride were effective in extracting capsanthin and capsaicin from red pepper, respectively. Mixed-solvent bore fruitful in increasing of oleoresin yield, but was fruitless in extracting capsanthin and capsaicin in comparison with single-solvent. In three varieties such as Juktoma, Jinsol and Dabok, Jinsol was excellent in oleoresin extraction. Optimum extracting temperature and time was $20^{\circ}C$ and three to five hours, respectively. Oleoresin quality from long-term storage and/or coarse red pepper were low in point of yield, capsanthin and capsaicin. Capsanthin and capsaicin were distributed into pericarp and seed in abundance, respectively. Optimum mixing ratio of red pepper powder to extracting solvent was suitable for one to three(1 : 3) or one to four(1 : 4) in oleoresin extraction.

• Journal of The Korean Association For Science Education
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• v.26 no.7
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• pp.805-812
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• 2006

In this study the description patterns of chemistry textbooks on the boiling point elevation phenomenon and the understanding patterns of high school students, pre-service teachers and chemistry teachers were investigated. High school chemistry II textbooks developed in the 6th and 7th national curricula were analyzed and the conception patterns of subjects on this phenomenon were categorized using a questionnaire developed for this study. The description patterns of science textbooks were classified into three: 'decreasing of surface solvent molecules', 'attraction force between solvent and solute molecules' and 'decreasing of surface solvent molecules and attraction force between solvent and solute molecules'. In the result of the conception analysis, the ratio of 'attraction force between solvent and solute molecules' was high among students, pre-service teachers, and chemistry teachers. There was a propensity that they would like to explain the boiling point elevation in terms of enthalpy rather than entropy, and in order to analyze this propensity, follow-up interviews were carried out.

• Applied Chemistry for Engineering
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• v.26 no.2
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• pp.234-238
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• 2015

The separation of nitrogen heterocyclic compound (NHC) contained in a model coal tar fraction was compared by the methanol and formamide extraction. The model coal tar fraction comprising four kinds of NHC (NHCs : quinoline, iso-quinoline, indole, quinaldine) and three kinds of bicyclic aromatic compound (BACs : 1-methylnaphthalene, 2-methylnaphthalene, dimethylnaphthalene), biphenyl and phenyl ether was used as a raw material. The aqueous solution of methanol and formamide were used as solvents. A batch-stirred tank was used as the raw material - a solvent contact unit of this work. Independent of the solvent used, the distribution coefficient of NHCs sharply increased by decreasing the initial volume ratio of water to the solvent and increasing the equilibrium operation temperature, whereas, the selectivity of NHCs in reference to BACs decreased. Decreasing the initial volume ratio of solvent to feed resulted in deteriorating distribution coefficients, but the selectivity of NHCs in reference to BAC was almost the constant. The distribution coefficient of NHCs by the methanol extraction was 3~5 times higher than that of NHCs by the formamide extraction, inversely, the selectivity of NHCs based on BACs by the formamide extraction was 3~7 times higher than that of NHCs by the methanol extraction. Furthermore, two different solvent extraction methods by adding the extraction processing speed to the balance between solvency and selectivity of NHCs were compared.

• Applied Chemistry for Engineering
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• v.25 no.2
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• pp.209-214
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• 2014

In this paper, the rheological behaviors and non-Newtonian characteristics of maltenes which is effected by hydrocarbon solvent type, solvent mixing ratio, temperature and shear rate was measured and compared with oil sands bitumen. Maltenes was made by SDA (solvent deasphalting) method from oil sands bitumen. Oil sands bitumen had apparent viscosities of $800{\sim}150000mPa{\cdot}s$ measured at a shear rate of $50sec^{-1}$ in the range of $25{\sim}85^{\circ}C$ and showed yield stress of 0.1~0.3 Pa at the temperatures below $35^{\circ}C$. All the oil sands bitumen and maltenes exhibited a shear-thinning, i.e. pseudoplastic behavior and apparent viscosity of maltenes decreased with decreasing carbon numbers of hydrocarbon solvent. The change in apparent viscosity with temperature could be described by the simple Guzman-Andrade equation, and maltene viscosities were decreased as the mixing ratio of n-pentane was raised. Also, all maltenes approached to Newtonian fluid as temperature were increased. the degree of pseudoplasticity was enhanced with decreasing carbon number of solvent.

• Clean Technology
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• v.23 no.4
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• pp.357-363
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• 2017

In this study, the supercritical carbon dioxide ($scCO_2$)/ n-butyl acetate (n-BA) co-solvent system was employed to remove an unexposed negative photoresist (PR) from the surface of a silicon wafer. In addition, the selectivity of the $scCO_2$/n-BA co-solvent system was confirmed for the unexposed and exposed negative PR. Optimum conditions for removal of the unexposed PR were obtained from various conditions such as pressure, temperature and n-BA ratio. The n-BA was highly soluble in $scCO_2$ without cloud point and phase separation in mostly experimental conditions. However, the $scCO_2$/n-BA co-solvent was phase separated at 100 bar, above $80^{\circ}C$. The unexposed and exposed PR was swelled in $scCO_2$ solvent at all experimental conditions. The complete removal of unexposed PR was achieved from the reaction condition of 160 bar, 10 min, $40^{\circ}C$ and 75 wt% n-BA in $scCO_2$, as measured by ellipsometry. The exposed photoresist showed high stability in the $scCO_2$/n-BA co-solvent system, which indicated that the $scCO_2$/n-BA co-solvent system has high selectivity for the PR removal in photo lithograph process. The $scCO_2$/n-BA co-solvent system not only prevent swelling of exposed PR, but also provide efficient and powful performance to removal unexposed PR.