• Journal of Powder Materials
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• v.6 no.2
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• pp.132-138
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• 1999

A new binder system and debinding process for low carbon residue in the injection molding of Nd(Fe, Co)B powder are investigated. In the injection molding of magnetic materials, it is demanded to reduce carbon residue which deteriorates their magnetic properties. The binder system developed is composed of polyethylene glycols (PEGs) and polypropylene (PP). PEG was selected as a major binder is component to be extracted in a molecular state by solvent extraction in ethanol, which step would leave no residue. PP was selected as a minor binder component to be subsequently removed by thermolysis which step would leave carbon residue. The behaviors of solvent extraction with the variations of PEG molecular weight, temperature, and time were examined. The dependency of residual carbon content on thermolysis atmosphere was also studied. Opened pore channels introduced in a green body by the solvent extraction and microstructures of the sintered magnets were observed using SEM.

• Bulletin of the Korean Chemical Society
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• v.33 no.7
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• pp.2251-2254
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• 2012

A rapid and practical green route for N-formylation of primary and secondary amines with formic acid at room temperature under the solvent-free conditions using HEU zeolite as a heterogeneous, reusable and highly efficient catalyst is described. The process is remarkably simple and environmentally benign. Excellent chemoselectivity was observed for the conversion of primary amines in the presence of secondary amines.

• Membrane Journal
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• v.23 no.5
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• pp.367-374
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• 2013

In the present study, Pebax-2533 plate membranes were prepared by drying precursor solutions which were obtained by dissolving Pebax-2533 polymer in 1-Propanol/n-Butanol mixed solvents. And then the $CO_2$ and $N_2$ permeation behaviors were tested by using a time-lag system. The prepared Pebax-2533 plate membranes showed a considerable $CO_2/N_2$ separation performance : the $CO_2$ permeability was 130 to 288 barr, and the $CO_2/N_2$ permselectivity was 5-8. The $CO_2$ permeation data obtained by varying feed pressure, permeation temperature, and solvent composition announced that not only the $CO_2$ sorption but also the $CO_2$ diffusion is equally important in the overall $CO_2$ permeation.

• Journal of Energy Engineering
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• v.28 no.4
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• pp.8-12
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• 2019

Thermal amine scrubbing is the most advanced CO₂ capture technique but its largescale application is hindered due to the large heat requirement during solvent regeneration step. The addition of a solid metal oxide catalysts can optimize the CO₂ desorption rate and thus minimize the energy consumption. Herein, we evaluate the solvent regeneration performance of Monoethanolamine (MEA) and Diethanolamine (DEA) solvents without and with two metal oxide catalysts (TiO₂ and V₂O₅) within a temperature range of 40-86℃. The solvent regeneration performance was evaluated in terms of CO₂ desorption rate and overall amount of CO₂ desorbed during the experiments. Both catalysts improved the solvent regeneration performance by desorbing greater amounts of CO₂ with higher CO₂ desorption rates at low temperature. Improvements of 86% and 50% in the CO₂ desorption rate were made by the catalysts for MEA and DEA solvents, respectively. The total amount of the desorbed CO₂ also improved by 17% and 13% from MEA and DEA solvents, respectively. The metal oxide catalyst-aided regeneration of amine solutions can be a new approach to minimize the heat requirement during solvent regeneration and thus can remove a primary shortfall of this technology.

• Bulletin of the Korean Chemical Society
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• v.32 no.spc8
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• pp.3149-3151
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• 2011

• Proceedings of the Korean Ceranic Society Conference
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• 2002.10a
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• pp.68.1-68
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• 2002

• Proceedings of the Korean Nutrition Society Conference
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• 2001.05a
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• pp.304.1-304
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• 2001

• The Korean Journal of Food And Nutrition
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• v.31 no.5
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• pp.647-652
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• 2018

Extracts from bay leaves, Chongbaek (Allium fistulosum L.), Hutgae (Hovenia dulcis Thunb.) fruit, and green tea, using Soju (Korean alcohol, $30^{\circ}$) as a solvent were analyzed for their antioxidative properties. The eels were evenly coated with the extract concentration equivalent to 2% of their total weight and dried for 15 hours at $35^{\circ}C$ using an air blower. The DPPH radical scavenging effect, acid value and peroxide value of semi-dried eel, and linoleic acid peroxidation of eel oil were investigated. The highest level of DPPH radical scavenging was found in green tea extracts, followed by Hutgae fruit extract and bay leaves extract (p<0.05). The acid value and peroxide value of Hutgae fruit extracts coated eels refrigerated for 21 days were the lowest followed by the green tea extract coated eels. During the 20 days reaction period, all four kinds of extracts analyzed were found to effectively decrease linoleic acid peroxidation. Among them, Hutgae fruit and green tea extracts decreased the peroxide content of eel oil steadily and for a longer period when compared to other extracts. In conclusion, pre-application of Hutgae fruit and green tea extracts on eels before drying was found to be effective in delaying peroxidation in eels during the drying process and refrigeration.

• Bulletin of the Korean Chemical Society
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• v.31 no.9
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• pp.2618-2626
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• 2010

In this paper poly (4-methyl vinylpyridinium hydroxide)/SBA-15 composite was prepared as a highly efficient heterogeneous basic catalyst by in situ polymerization method for the first time. It was characterized by XRD, FT-IR, BET, TGA, SEM and back titration using NaOH. This catalyst exhibited the excellent catalytic activities for the Knoevenagel condensation of various aldehydes with ethyl cyanoacetate. Over this catalyst, ${\alpha},{\beta}$-unsaturated carbonyl compounds were obtained in the reasonable yield at $95^{\circ}C$ in 10 - 30 min in $H_2O$ as a solvent with a 100% selectivity to the condensation products. Catalyst could be easily recycled after the reaction and it could be reused without the significant loss of activity/selectivity performance. No by-product formation, high yields, short reaction times, mild reaction conditions and operational simplicity with reusability of the catalyst were the salient features of the present synthetic protocol. Presence of $H_2O$ as a solvent was also recognized as a "green method".

• Journal of the Korean Chemical Society
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• v.17 no.6
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• pp.411-415
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• 1973

The reaction between cyanide ion and triphenyl methane dyes is subject to marked catalysis by cationic micelles of cetyltrimethyl ammonium bromide(CTABr) and retarded by anionic micelles of sodium lauryl sulfate(NaLS). Added salts, anions inhibit the catalysis by CTABr, and cations, especially $Zn^{++},\;Cd^{++}$ decrease the retardation of the reaction rates in the presence of NaLS. The kinetic effects of the ionic micelles are much larger in water than in ethanol-water, methanol-water, propanol-water and acetone-water, but strange solvent effects, acceleration the reaction rates, was found in the reaction with malachite green in water-methanol system.