• Journal of the Korean Applied Science and Technology
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• 제27권4호
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• pp.421-426
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• 2010

The transesterification of rapeseed oil, soybean oil, and mixed fat were conducted at $65^{\circ}C$ with $Al_2O_3$-supported CaO, 0.8 wt% KOH, 1 wt% NaOH and mixed catalyst. The overall conversion(%) of rapeseed oil indicated to be 96% at the 12:1 molar ratio of methanol to oil, 8 wt% CaO and 2 wt% water. The pH ranges of biodiesel for mixed fat using four catalysts and for three fats using 8wt% CaO were 7.3-9.1, 7.3-7.5, respectively. The volumes of water needed to wash biodiesel from rapeseed oil using 0.8 wt% KOH and 8 wt% CaO were 15 mL and 3 mL.

• Journal of the Korean Ceramic Society
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• 제27권7호
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• pp.883-890
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• 1990

Although various theories have been presented on the mechanism of setting retardation of 3CaO·Al2O3, this phenomenon has not yet been defined. The present investigation was initiated in order to solve the mechanism from the view point of coordination chemistry. The solubility of Ca(OH)2 in aquous solution of soldium gluconate was abnormally high, and was proportional to the concentration of sodium gluconate. These phenomena were attributed to the soluble complex formation, that is, (1 : 1)Ca complex formation between calcium ion and gluconate ion. The author's proposal was further confirmed by the results of electrical conductivity measurement. The formation of calcium complex was also supported by IR spectra and DTA. When sodium gluconate was dissolved in 3CaO·Al2O3 suspension, calcium complex and aluminum complex were formed. As an experimental evidence, the asymmetric stretching vibration of carboxyl group in sodium gluconate was observed to be shifted to lower frequency from 1625cm-1 to 1585cm-1 characteristically. The characteristic exothermic peaks of the complexs at 430℃ and 700℃ observed in DTA curve also suggest the formation of the complexs between sodium gluconate and 3CaO·Al2O3.

• Applied Chemistry for Engineering
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• 제9권7호
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• pp.1070-1078
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• 1998

Thermodynamic analysis on carbon dioxide reforming of methane was performed using a computer program which can handle condensed species in the products, and the reforming experiments were conducted over $Al_2O_3$, $La_2O_3$, ZSM-5, MCM-41, KIT-1 supported nickel catalysts, and a commercial ICI 46-1. It was estabished that a system which consists of $CH_4$, $CO_2$, CO, $H_2$, $H_2O$, and C is appropriate for theoretical equilibrium calculations and addition of water vapor or oxygen was found to diminish the contribution of carbon dioxide in reforming. Silicate molecular sieve-supported catalysts such as Ni/ZSM-5, Ni/MCM-41, Ni/KIT-1 were effective for high $CH_4$ and $CO_2$ conversions as well as for high CO yield. Coke formation was suppressed when CaO was added as a promoter. Ni/Ca/KIT-1 which contains 10% Ni with 3% Ca showed conversion approaching equilibrium levels above $650^{\circ}C$ and maintained constant activity over 20 h. Despite increased space velocity, relatively high conversion and CO yield were observed.

• Journal of the Korean Chemical Society
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• 제19권5호
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• pp.317-324
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• 1975

The adsorptions of gaseous $H_2O\;and\;D_2O\;on\;Na^+-,\;Ca^{2+}-,\;and\;Al^{3+}$ montmorillonites at various temperatures were undertaken. Break down of ir hydroxyl stretching bands into four Gaussian components was made by means of manual technique. Resonance theory of water to form silanol hydroxyl group was supported by $3625cm^{-1}$ band for OH and $2680cm^{-1}$ band for OD which depend on amounts of water adsorbed. The broad bands at about $3400 cm^{-1}\;and\;2475cm^{-1}$ were assigned to stretching band of silanol OH hydrogen bonded to adsorbed water. The prominent $3230 cm^{-1}$ band together with component around $2345 cm^{-1}$ were attributed to adsorbed $H_2O\;and\;D_2O$ respectively. The chemical nature of the hydrogen bonding between adsorbed water and neighboring surface OH was explained adequately in terms of electrostatic interaction.

• Bulletin of the Korean Chemical Society
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• 제31권8호
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• pp.2242-2246
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• 2010

New 3,7-diphenylthieno[3,2-e]bis[1,2,4]triazolo[4,3-a:4',3'-c]pyrimidine derivatives were easily synthesized at room temperature in good yield by the oxidative cyclization of thienopyrimidinyl hydrazones with alumina-supported calcium hypochlorite ($Ca(OCl)_2/Al_2O_3$).

• Applied Chemistry for Engineering
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• 제5권5호
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• pp.808-818
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• 1994

Effects of ceria additive on the activity and thermal aging behavior of supported Ru catalysts were investigated using Ru/${\gamma}$-$Al_2O_3$and Ru/$CeO_2$-${\gamma}$-$Al_2O_3$. The catalysts were characterized by $^{129}Xe$-NMR and $H_2$ chemisorption. The cataltic activity for conversion of CO, HC and $NO_x$ was measured using simulated automobile engine exhausts under lean, rich and stoichiometric conditions. For both fresh and aged catalysts, Ru/$CeO_2$-${\gamma}$-$Al_2O_3$ was more active than Ru/${\gamma}$-$Al_2O_3$ for all three pollutants. Results of $^{129}Xe$-NMR and $H_2$ chemisorption indicated that sintering of Ru particles occurred to the same extent for both catalysts during the thermal aging process. After thermal aging at 673K, however, the catalytic activity of the aged Ru/$CeO_2$-${\gamma}$-$Al_2O_3$ was substantially higher than that of the fresh one, while the activity of Ru/${\gamma}$-$Al_2O_3$ decreased after the thermal aging. This finding may suggest new active sites were created during the thermal aging, probably in the vicinity of the interface between Ru and Ce. For more quantitative investigation of the effect of a cation such as Ce on the thermal aging of Ru metal particles, Ru catalysts supported on cation-exchanged Y-zeolites were used as the model catalysts. The results indicated that when Ba, Ca, La, Y or Ce was used for the cation exchange, the exchanged cation did not affect the thermal aging behavior of Ru in Y-zeolite, as evidenced by $^{129}Xe$-NMR and EXAFS.

• Advances in Energy Research
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• 제1권1호
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• pp.1-12
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• 2013

In this work, we present the catalytic dehydrogenation of hydrazine borane $N_2H_4BH_3$ (HB) using supported nickel catalysts at $50^{\circ}C$. In the presence of monometallic nickel catalysts, the dehydrogenation of HB is a one-step reaction consisting of the hydrolysis of the $BH_3$ group only. The challenge is to activate nickel to make it reactive towards the $N_2H_4$ moiety of HB. A set of 52 catalysts were prepared by using 2 supports ($Al_2O_3$ and $TiO_2$), 5 nickel precursors and 3 preparation methods. For the first time, we show that the supported nickel catalysts are able to dehydrogenate the $NH_3$ moiety of HB. In our experimental conditions, the best results were obtained with 20 wt% Ni-$Al_2O_3$ and 20 wt% Ni-$TiO_2$, with ca. 190 mL $H_2+N_2$ generated over a total theoretical volume of 283 mL, suggesting $H_2$ selectivity of 37 and 32%, respectively. Both catalysts were then characterized by EDX, XPS, and XRD. Our achievement is the first step forward and opens new perspectives for developing catalysts for the total dehydrogenation of HB.

• Journal of the Korean Society of Food Science and Nutrition
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• 제38권9호
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• pp.1284-1288
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• 2009

Identification of various inorganic compound crystals contained in solar salts, which are produced from 12 areas of Jeonnam, was firstly made by the X-ray diffraction (XRD) technique. The analysis of the XRD spectra was carried out on the basis of Joint Committee on Powder Diffraction Standards (JCPDS) data and the results of Energy Dispersive X-ray Spectrometer (EDX) measurements. In particular, the analysis of the XRD spectra supported that each solar salt contains $Na_2S$ (Shinan Jeungdo and Sinui), $KMgCl_3$ (Shinan Bigeum), $Ca(ClO_3)_2$ (Shinan Docho), $CaAl_4O_7$ (Haenam Songji), $CaSiO_3$ and $CaCl_2$ (Goheung) as inorganic compound crystals, which have not been reported for the solar salts. Also, the XRD results indicated that the solar salts maintain a cubic NaCl crystal structure without any change of lattice parameters etc. However, it was shown in the Field Emission Scanning Electron Microscope (FE-SEM) images that an external form of the solar salts has a lamination layer shape of a cubic structure, which is different from a simple cubic form for the purified salts and the reagent NaCl.

• Korean Chemical Engineering Research
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• 제44권3호
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• pp.307-313
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• 2006

In order to improve the efficiency of methane steam reforming process, a part of the system which produces hydrogen from heavy hydrocarbon resources such as coal, we combined metal catalyst with CaO sorbent and fabricated catalyst/sorbent. To increase the porosity and the compressive strength of sorbent, carbon black and ${\alpha}-alumina$ were mixed with CaO powder during preparation. The effects of sorbent composition on the physical properties were investigated by SEM, TGA, BET, XRD, abrasion strength measuring device and adsorption-desorption instrument. Sorbent with 5 wt％ $Al_2O_3$ and 10 wt％ carbon black showed the best physical features with $7.61kg_f$ strength and 47％ $CO_2$ adsorption capability. Various metal catalysts such as Ni, Co and Fe were supported on the sorbent developed and 10 wt％ Ni/sorbent was selected for methane steam reforming process based on the result of reaction experiment. The reaction system using the catalyst/sorbent showed better $H_2$ productivity compared to the detached system with catalyst and sorbent, indicating the effectiveness of the system developed in this study.

• Journal of the Korean Chemical Society
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• 제18권3호
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• pp.180-188
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• 1974

Adsorption mechanism of alkyl aldehydes, acetaldehyde, acrolein, and crotonaldehyde on cations supported by layer silicates was studied by means of IR spectroscopy and X-ray. An analysis of four characteristic split bands in the region of $1720∼1580㎝^{-1}$ was made. The carbonyl stretching band which shifted about $130㎝^{-1}$ to lower frequencies was observed only for $Ni^{2+}$ and Al^{3+}$ but slightly with $Ca^{2+}$ at high sample temperature and was attributed to >C=O…M complex formation. A sharp band which appeared as a shoulder at 1722 for acetaldehyde and 1690 for acrolein and crotonaldehyde was responsible for the interaction of carbonyl with surface hydroxyl. The second broad band which appeared at about 1710~1660 was responsible for hydrogen bonding between carbonyl oxygen and cationic hydroxyl group. The third band which appeared at about 1640~1660 was attributed to induced >C=C< double bond due to the strong carbonyl interaction. This was supported by the interlamellar spacings obtained by X-ray diffractometry.