• Transactions of the Korean hydrogen and new energy society
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• v.26 no.4
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• pp.339-346
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• 2015

The synthesis of Fischer-Tropsch (FT) oil is the catalytic hydrogenation of CO to give a range of products, which can be used for the production of high-quality diesel fuel, gasoline and linear chemicals. This studied catalyst was prepared Cobalt-supported alumina and silica by the incipient wet impregnation of the nitrates of cobalt, promoter and organic solvent with supports. Cobalt catalysts were calcined at $350^{\circ}C$ before being loaded into the FT reactors. After the reduction of catalyst has been carried out under $450^{\circ}C$ for 24h, FT reaction of the catalyst has been carried out at GHSV of 4,000/hr under $200^{\circ}C$ and 20atm. From these experimental results, we have obtained the results as following; In case of $SiO_2$ catalysts, the activity of 12wt% $Cobalt-SiO_2$ synthesized by organic solvent was about 2 or 3 times higher than the activity of 12wt% $Cobalt-SiO_2$ catalyst synthesized without organic solvent. In particular, the activity of the $Cobalt-SiO_2$ catalyst prepared in the presence of an organic solvent P was two to three times higher than that of the $Cobalt-SiO_2$ catalyst prepared without the organic solvent. Effect of Cr and Cu metal as a promoter was found little. 200 h long-term activity test was performed with a $Co/SiO_2$ catalyst prepared in the presence of an organic solvent of Glyoxal solution.

• Analytical Science and Technology
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• v.29 no.6
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• pp.300-304
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• 2016

The asphalt antistripping agents were synthesized from ethylenediamine (ED) or N,N'-bis(2-hydroxyethyl)ethylenediamine (HEED) with three different fatty acids. The formation of amide bonds were successfully performed and confirmed by FT-IR and $^1H-NMR$ data. The adhesive properties of antistripping agents were compared in terms of contact angle and BBS test. The reaction product of ED with waste animal fat exhibited the most hydrophobic by the contact angle measurement, and the strongest water resistance of 94 % by BBS test. However, the reaction product of ED with waste vegetable oil showed the strongest absolute bond strength of ca. 3610 and 3227 kPa for before and after water conditioning, respectively. For the bond strength in general, the reaction products of ED were superior to HEED reaction products, and the reaction products of animal fat and waste vegetable oil were superior to those of pure soybean oil.

• Korean Chemical Engineering Research
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• v.50 no.2
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• pp.282-291
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• 2012

The PGLE and PGLE3 nonionic surfactants were synthesized from the reaction between glycidol and lauryl acid and their structures were confirmed by $^1H$ and $^{13}C$ NMR analysis. The CMCs of PGLE and PGLE3 surfactants were found to be $3.59{\times}10^{-2}$ mol/L and $8.80{\times}10^{-2}$ mol/L respectively and the surface tensions at their CMC conditions were 26.09 mN/m and 28.68 mN/m respectively. Dynamic surface tension measurement has shown that the adsorption rate of surfactant molecules at the interface between air and surfactant solution was found to be relatively fast in both surfactant systems, presumably due to high mobility of surfactant molecules. The contact angles of PGLE and PGLE3 nonionic surfactants were $25.5^{\circ}$ and $9.5^{\circ}$ respectively. Dynamic interfacial tension measurement showed that both surfactant systems reached equilibrium in 20 minutes and the interfacial tensions at equilibrium condition in both systems were 0.42 mN/m and 0.53 mN/m respectively. The PGLE surfactant system has indicated higher foam stability than the PGLE3 surfactant system, which is consistent with surface tension measurement. The phase behavior experiments performed at $25{\sim}60^{\circ}C$ in systems containing nonionic surfactant, water, n-hydrocarbon oil and cosurfactant showed a lower phase or oil in water microemulsion in equilibrium with excess oil phase at all conditions investigated during this study.

• Applied Chemistry for Engineering
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• v.30 no.4
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• pp.435-444
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• 2019

In this study, two types of nonionic saccharide biosurfactants, GP-6 and GP-7, were prepared from coconut oil and the structure of resulting products was investigated by FT-IR, $^1H-NMR$ and $^{13}C-NMR$ spectrophotometer. The interfacial properties of GP-6 and GP-7 were found to be excellent from interfacial property measurements such as critical micelle concentration, static and dynamic surface tensions, interfacial tension, emulsification power, wetting property and foam stability. Detergency test evaluated by using a Terg-o-tometer showed moderately good detergency compared to that of conventional surfactants used in detergent formulations. Biodegradability, acute oral toxicity, acute dermal irritation and acute eye irritation tests revealed that both surfactants possess excellent mildness and superior environmental compatibility indicating the potential applicability to detergent products formulations. In particular, GP-6 can be considered as a strong candidate in detergent formulations since it is more surface active, mild and readily biodegradable than GP-7.

• Applied Chemistry for Engineering
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• v.24 no.5
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• pp.530-536
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• 2013

Vegetable oil-based dimer acid derivatives were prepared through a two-step procedure and their lubricating properties for diesel fuel were evaluated using high frequency reciprocating ring (HFRR) method to investigate wear scar diameter (WSD). Diels-Alder reaction at an elevated temperature transformed fatty acid to dimer acid, subsequently converted into dimer acid derivatives by esterification with methanol. It should be noted that the derivatives were dissolved well in diesel oil up to 1 wt%. After adding 120 ppm of the derivatives to pure diesel, the WSD significantly decreased to $300{\sim}05{\mu}m$, compared to $552{\mu}m$ of WSD in pure diesel. Dimer acid derivatives having carboxylic acid show superb in lubricating property which does not depend on the alkyl group in the derivatives.

• Journal of the Mineralogical Society of Korea
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• v.18 no.3 s.45
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• pp.147-153
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• 2005

Naldrettite, recently discovered in the Mesamax Northwest deposit, Ungava region, northern Quebec, Canada, was reported as a new mineral. In order to confirm whether itis a natural equivalent of synthetic $Pd_2Sb$ phase or not, the pure $Pd_2Sb$ phase has been synthesized and investigated by reflected microscope, electron microprobe analyser, X-ray diffractometer, and micro-indentation hardness tester. Under reflected light synthetic $Pd_2Sb$ Phase is white with a creamy tint in both air and oil and weakly bireflectant. Anisotropism is strong, from brownish gray to greenish blue in air. Micro-indentation hardness test gives VHN100=293(242-322). Composition of the phase is $63.7\~64.3wt.\%\;Pd\;and\; 36.4\~36.8wt.\%$ Sb, and is entirely consistent. The phase, quenched from $500^{\circ}C$, is orthorhobic with space group $Cmc2_1$, and the cell parameters are a=3.366(1), b=17.523(3), c=6.929(2) ${\AA}$. All mineralogical properties of synthetic $Pd_2Sb$ compare very well with those of naldrettite, confirming that naldrettite is the natural analogue of the synthetic $Pd_2Sb$ phase.

• Applied Chemistry for Engineering
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• v.34 no.4
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• pp.434-443
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• 2023

We have investigated the performance improvement of grease by synthesizing calcium sulfonate grease as an alternative to lithium grease, which is widely used globally. Since the composition ratio of the grease, when manufactured, is usually 50% base oil and 50% thickener, using grease as a lubricant in a cryogenic environment is not encouraged due to its inferior low-temperature performance. In this study, we have synthesized three types of calcium sulfonate grease with paraffin oil and PAO-based base oil and thickener. Furthermore, lithium grease was synthesized via saponification with PAO-based base oil, lithium hydroxide, 12-hydroxystearic acid, and sebacic acid. We have measured low-temperature characteristics using a rheometer and low-temperature torque meter, and tribology characteristics were obtained using a four-ball lubricant tester and schwingung reibung verschleiß (SRV). As a result, the flow point of the calcium sulfonate grease synthesized with a PAO-based base oil and thickener was found to be -40℃, overcoming the existing calcium sulfonate grease's low-temperature limitation. Moreover, the synthesized calcium sulfonate grease showed low-temperature performance similar to that of lithium grease synthesized with PAO base oil, but superior anti-wear, extreme pressure, coefficient of friction, heat resistance, adhesion, and corrosion resistance. It is thus expected to commercially replace the existing lithium grease.

• Journal of Life Science
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• v.29 no.3
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• pp.332-336
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• 2019

Obesity is associated with an increased risk of many diseases including type 2 diabetes mellitus, hypertension, and hyperlipidemia. The flowers of Chrysanthemum boreale have been used as traditional medicines for the treatment of diseases such as obesity and type 2 diabetes mellitus. This study aimed to evaluate the effect of C. boreale Makino flower essential oil (CFEO) on adipocyte differentiation using preadipocyte cell line 3T3-L1. CFEO at concentrations between 0.1 and $5{\mu}g/ml$ did not affect 3T3-L1 cell viability. A CFEO concentration of between 0.1 and $1{\mu}g/ml$ significantly inhibited lipid accumulation during MDI-induced differentiation in 3T3-L1 cells in a dose-dependent manner, reaching a maximal level at $1{\mu}g/ml$ ($28.94{\pm}2.01%$; approximately 30% of control treated with MDI alone). Western blot analysis revealed that CFEO concentrations between 0.1 and $1{\mu}g/ml$ suppressed the activations of three adipogenic transcription factors in the MDI-stimulated 3T3-L1 cells: peroxisome proliferator-activated receptor ${\gamma}$; CCATT/enhancer binding protein ${\alpha}$; and sterol regulatory element binding protein-1. Moreover, the expressions of lipogenic enzymes, acetyl-CoA carboxylase, and fatty acid synthase were also inhibited by treatment with CFEO between 0.1 and $1{\mu}g/ml$. CFEO may therefore be a promising functional material for obesity prevention.

• Journal of the Korean Ceramic Society
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• v.25 no.4
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• pp.415-423
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• 1988

Mixtures of carbon and silica (about 0.46${\mu}{\textrm}{m}$) which was synthesized by the hydrolysis of ethyl silicate, the molar ratio of silica/carbon was fixed as 1/10(weight ratio : 1/2), were nitrided in the temperature range 135$0^{\circ}C$~150$0^{\circ}C$. The phse of the product Si3N4 was $\alpha$ phase and the morphology was hexagnoal prism and the nitridation reaction was completed in 5 hrs at 150$0^{\circ}C$ or 7hrs at 145$0^{\circ}C$. The reaction rate above 150$0^{\circ}C$ was diffusion-controlled, following Jander equation. Activation energy Q was derived from the Arrhenius plot and the value was about 101kcal/mol. Axis ratio of Lattice constants(c/a) was 0.726 and unit volume was $\AA$3, the larger the molar ratio of carbon/Alkoxide was, the smaller the particle size of $\alpha$Si3N4 was.

• Journal of the Korean Ceramic Society
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• v.24 no.5
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• pp.500-506
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• 1987

In order to synthesize monodispersed spherical silica fine particles, we investigated the reaction of hydrolysis of 0.05∼4.0 mole Si(OC2H5)4-0.01∼7.60mole NH3 -0.24∼38.40 mole H2O-2.62∼16.88mole C2H5OH systems. The range of the composition of solution which spherical silica particles were formed was enlarged according to an increase in concentration of Si(OC2H5)4. Larger particles were obtained at higher molar ratios of Si(OC2H5)4/C2H5OH, NH3/H2O and H2O/Si(OC2H5)4 and at a lower reaction temperature.