• Journal of Nutrition and Health
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• v.36 no.1
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• pp.32-39
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• 2003

Phytoestrogens, especially soy-derived isoflavones, are receiving great scrutiny as a food supplement for preventing hormone dependent disease such as postmenopausal osteoporosis. Their beneficial effects are derived from aglycone form of isoflavones, such as daidzein, genistein or glycitein. In contrast to the common usage of soybean, black bean (Rhynchosia Molubilis : Yak-kong) has been used as a supplement for preventing postmenopausal osteoporosis in oriental medicine. To investigate the effects of the saliva, artificial stomach fluid, and digestive enzymes on the conversion of glycosidic isoflavone to aglycone form, soybean and black bean were extracted with 70% methanol and freeze-dried. The recovery yield of methanol extracts of black bean was 14.1% which was higher than that of soybean, 13.5%. In terms of total isoflavones, we routinely obtained larger amount of isoflavones from black bean than those from soybean. By incubating methanol extracts of soybean and black bean with IN HCI for 180 min, the proportions of aglycones relative to the total isoflavone were significantly increased (32.4% and 52.4%, respectively). In vitro conversion, digestive enzymes ($\beta$-glucosidase and $\alpha$-glucosidase) may hydrolyze glycosidic bond of isoflavone more effectively than saliva or artificial stomach fluid did. It seems to say that the activity of $\beta$-glucosidase was higher than those of $\alpha$-glucosidase. The rate of conversion of glucoside form to aglycone form in black bean and soybean was low in physiological condition (pH) tested, although the enzymatic hydrolysis of glucoside was active. These results demonstrated that the composition of aglycone in food may be the important factors in terms of the bioavailability of isoflavones. (Korean J Nutrition 36(1): 32-39, 2003)

• Bulletin of the Korean Chemical Society
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• v.23 no.8
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• pp.1135-1138
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• 2002

CuO/ZnO, CuO/SiO,sub>2, and CuO/ZrO2 catalysts were prepared for investigating the support effects on methanol dehydrogenation. It was found that the conversion of methanol was proportional to the copper surface area on Cu/ZnO cat alysts and was independent on that on Cu/ZrO2 and Cu/SiO2. The highest copper surface area was obtained with the Cu/ZrO2 (9/1). The unusual deactivation of the Cu/ZnO, which showed the highest selectivity among the catalysts tested, was observed. Pulse reaction with methanol indicated that the lattice oxygen in ZnO could be removed by forming CO2 in the catalytic reaction, supporting that the ZnO reduction was responsible for the severe deactivation of the Cu/ZnO.

• Applied Chemistry for Engineering
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• v.2 no.4
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• pp.363-371
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• 1991

The catalytic performance and availability of heteropoly compounds for the conversion of methanol to hydrocarbons have been studied. The effects of reaction conditions such as reaction temperature, methanol partial pressure and residence time and the effects of ion-exchange of the catalysts were examined for enhancing the yield of hydrocarbons and the selectivity of low olefins. Their acid strength depended on the kind of countercation, and the yield of hydrocarbons and the selectivity for propylene to propane were closely related to the electronegativity of the corresponding countercations. In contrast to the other heteropoly compounds, the ammonium salt showed a considerably high catalytic activity and a high selectivity for paraffins to low olefins.

• Korean Chemical Engineering Research
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• v.44 no.4
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• pp.345-349
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• 2006

Conversion of DME (dimethyl ether) or methanol to light olefins (ethylene, propylene, butenes) over SAPO-34 were systematically studied, where it was observed that DME was dehydrated to light olefins and partially converted to by-products such as CO and $CO_2$ at various reaction temperatures on the time-on-stream. SAPO-34 catalyst during the DTO (dimetyl ether-to-olefins) reaction was significantly deactivated compared with MTO (methanol-toolefins) reaction. By addition of water to the reaction feed, the yield to light olefins was not only increased, but the life time of the catalyst was also prolonged by the suppression of the coke formation by steam.

• Proceedings of the Ginseng society Conference
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• 2002.10a
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• pp.486-490
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• 2002

In different approaches ginsenosides were extracted from Korean ginseng roots by ammonia and for comparison with methanol-water and water. The extracts have been analyzed qualitatively and quantitatively to evaluate yield and selectivity of extractions of ginsenosides. Water supplied the lowest yield. The yields of extracts with liquid ammonia were higher than those with methanol-water. However, this is partly due to the conversion of malonyl ginsenoside to normal ginsenosides by ammonia. It was proved by HPLC that malonyl-ginsenosides $m-Rb_1,\;m-Rb_2,$ m-Rc and m-Rd were converted to the corresponding neutral ginsenosides. Furthermore, ginsenosides from ginseng roots were extracted by alkaline methanol-water $(60\%)$ solutions. Alternatively, the extracts of the methanol-water $(60\%)$ extraction were treated with sodium hydroxide solution. Both methods also convert the malonyl-ginsenosides to neutral ginsenosides.

• Journal of the Korean Chemical Society
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• v.34 no.4
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• pp.360-369
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• 1990

Borosilicate, HZSM-5 zeolite and iron-substituted borosilicate and HZSM-5 zeolite were prepared and their catalytic properties in methanol conversion were studied. The effects of strength and amount of acid site determined from TPD spectra of ammonia on the product distribution was examined. Selectivity to propylene was high over borosilicate with small amount of strong acid site, but selectivity to aromatic compound was high over HZSM-5 zeolite with large amount of the strong acid site. The participation of weak acid site on the conversion did not confirmed, and the product distribution could be explained in terms of the amount of the strong acid site. Although the amount of the weak acid site was increased by substitution of iron, there was no meaningful change in the product distribution.

• Proceedings of the KAIS Fall Conference
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• 2011.05a
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• pp.141-143
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• 2011

Al-SBA-1(Si/Al = 40, 80 and 120) and Al,Mg-SBA-1 (Si/(Al+Mg) = 40 and 80) molecular sieves were synthesized and characterized. Acetalization of n-heptanal with methanol was studied under autogenous pressure between 80 and $150^{\circ}C$. Since protonation of n-heptanal was fast, addition of methanol to the same to formed hemiacetal slowly whereas conversion of hemiacetal to acetal was fast. The catalysts exhibited nearly similar conversion irrespective of their difference in acidity, and all of them showed more than 80 % conversion either at 80 or $100^{\circ}C$. Hence it is evident that the difference in acidity is not so important in differentiating the activity of the catalysts. The large pore size and hydrophilic and hydrophobic properties are suggested to be the main factors that control acetalization.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.3
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• pp.209-219
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• 2019

Methanol is a liquid fuel which could also be produced from renewable energy sources and has appreciably high energy density. In this work, we investigated the application of $Ce_{0.9}Gd_{0.1}O_{2-x}$ supported Cu and Ni catalysts for hydrogen production via methanol steam reforming. Catalysts were synthesized by solution combustion synthesis. The prepared catalysts with various active materials and Cu loading amounts were tested in a reactor at $200-300^{\circ}C$, 0-5 barg range and steam to methanol molar ratio was 1.5. The catalytic properties of Cu and Ni were compared, and the catalytic performance was shown to depend on the amounts of metal loading and operating conditions such as reaction temperature and pressure.

• Journal of the Korean Institute of Gas
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• v.26 no.2
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• pp.14-20
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• 2022

In this study, the catalytic reaction characteristics for producing hydrogen using methanol steam reforming were investigated. Nickel and copper are frequently used in steam reforming reaction and methanol synthesis, were used as main active metals. As a support, hydrotalcite has a high specific surface area, excellent porosity and thermal stability, and has weak Lewis acid sites and basic properties. Hydrotalcite was used to identify catalysts of methanol steam reforming with catalytic activity and their properties. In this research, high reactivity was shown in the catalyst of copper metal with high reducibility. And increasing of active metal loading showed the higher the methanol conversion and hydrogen selectivity.

• Korean Membrane Journal
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• v.6 no.1
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• pp.10-15
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• 2004

We developed a water-selective ceramic composite membrane for use as a dehydration membrane reactor for dimethylether (DME) synthesis from methanol. The membranes were modified on the porous stainless steel support by the sol-gel method accompanied by a suction process. The improved membrane modification process was effective in increasing the vapour permselectivity by removal of defects and pinholes. The optimized alumina/silica composite membrane exhibited a water permeance of 1.14${\times}$10$^{-7}$ mol/$m^2$.sec.Pa and a water/methanol selectivity of 8.4 at permeation temperature of 25$0^{\circ}C$. The catalytic reaction for DME synthesis from methanol using the membrane was performed at 23$0^{\circ}C$, and the reaction conversion was compared with that of the conventional fixed-bed reactor. The reaction conversion of the membrane reactor was much higher than that of the conventional fixed-bed reactor. The reaction conversion of the membrane reactor and the conventional fixed-bed reactor was 82.5 and 68.0%, respectively. This improvement of reaction efficiency can last if the water vapour produced in the reaction zone is removed continuously.