• Applied Biological Chemistry
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• v.40 no.5
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• pp.442-446
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• 1997

A new analytical method was developed by HPLC after supercritical fluid extraction and fluorogenic derivatization for the determination of quinclorac (3,7-dichloro-8-quinoline carboxylic acid) in soil. The graminicide quinclorac was extracted from soil by supercritical fluid extraction. Supercritical carbon dioxide at 7000 psi $(80^{\circ}C)$ modified with 30% of methanol extracted quinclorac from soil samples at the level of $0.1ng\;g^{-1}$ with 96% recovery. Extracted quinclorac was determined by HPLC as a fluorescent derivative. Derivatization was made with 4-bromomethyl-7-methoxycoumarin (4-Br-Mmc) using 18-crown-6-ether as a catalyst. The conversion was completed within 30 min and the limit of detection was 0.5 ppb to prove that the procedure could be used in the residue analysis of the pesticides containing carboxylic acid group.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.4
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• pp.391-397
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• 2011

The use of Hydrogen as a fuel is receiving considerable attention and as a result, research on novel methods of hydrogen production is necessary so that the hydrogen demands in the future can be satisfied. This study presents experimental data on methanol Autothermal Reformation that quantifies the relationship between the oxygen-to-methanol ratio ($O_2/CH_3OH$) and reformer efficiency. For each catalyst configuration, the $O_2/CH_3OH$ was varied from 0.1 to 0.4, with an increment of 0.05, to investigate the effects of $O_2/CH_3OH$ on the reactor performance, including temperature profile, conversion, and efficiency. $O_2/CH_3OH$ was increased from 0.15 to 0.20, and the catalyst bed temperature increased by $235^{\circ}C$ to approximately $550^{\circ}C$. The catalyst bed temperature increased with increasing $O_2/CH_3OH$ as the reaction shifted from endothermic to exothermic reaction and as a result, excess heat, which raised the reactor temperature, was generated. The reactor performance was shown to be highly dependent on $O_2/CH_3OH$. The optimum $O_2/CH_3OH$ = 0.30 found in the experimental tests is 30% higher than the theoretical optimum of 0.23. This is attributed to a combination of factors such as the concentrations of the $O_2$ and $CH_3OH$ gas, reaction rate, catalyst effects, heat loss from the reactor, and the difference between the actual amounts of reaction products formed and the theoretical amounts of the reaction products.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.380-389
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• 2020

The conversion characteristics and fuel properties for producing biodiesel (BD) by blending beef-tallow, an animal waste resource with a high-saturated fatty acid content, and sunflower-oil, a vegetable oil with a high-unsaturated fatty acid content, were investigated. For this investigation, the effects of the control factors, such as the oil-blend ratio and methanol-to-oil molar ratio, on the fatty acid methyl ester and BD production yield were also investigated. The kinematic viscosity reduction effects of BD using heating and ultrasonic irradiation were verified, and the optimal temperature of each BD-diesel fuel blend for reducing the kinematic viscosity was derived using the correlation equation. As a result, the optimal conditions for producing blended biodiesel were verified to be TASU7 and a methanol-to-oil molar ratio of 10:1. The analysis results of the fuel properties of TASU7 satisfied the BD quality standard; hence, the viability of BD blended with waste tallow as fuel was verified. The experimental results on the kinematic viscosity reduction showed that heating is more effective in reducing the kinematic viscosity because it took less time than ultrasonic irradiation, and the equipment was cheaper and more straightforward than the ultrasonic irradiation method.

• Journal of Adhesion and Interface
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• v.2 no.4
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• pp.10-23
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• 2001

In order to increase the lower values of % grafting and monomer conversion in the emulsion graft polymerization of methylmethacrylate(MMA) onto sodium alginate (SA; a polymer electrolyte) with alginic acid-g-PMMA, the graft polymerization with water soluble (methanol and acetone) and insoluble solvents was carried out using a varity of solvent amounts and agitating rates. And some physical properties of the graft polymer were also investigated. In the polymerizations with water insoluble solvent, there were pronounced improvements in both % grafting and MMA conversion by the promotion of MMA diffusion from the core to the SA adsorpted on the outer layer of particle and that of MMA complex formation with SA. And the effect was larger for the solvents (cyclohexane, decalin) which do not dissolve PMMA. On the other hand, in the polymerization with water soluble solvent, there was an significant increase in MMA conversion and a considerable increase in the % grafting by the destruction of electrical double layer around the SA chains, abstracting the hydrated water in the layer and the effect was more potential in the case of methanol which is a precipitant of PMMA.

• Journal of the Korean Applied Science and Technology
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• v.27 no.4
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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.

• Polymer(Korea)
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• v.35 no.4
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• pp.284-288
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• 2011

For the purpose of the pre-industry production of poly(L-lactide) (PLLA) and full understanding of the supercritical polymerization system, large scale polymerization of L-iactide initiated by 1-dodecano/stannous 2-ethyl-hexanoate (DoOH/Sn(Oct)$_2$) was carried out in supercritical chlorodifluoromethane under various reaction conditions (time, temperature and pressure)and reactants (monomer and supercritical solvent) concentrations. A 3 L sized-reactor system was used throughout this study. The monomer conversion increased to 72% on increasing reaction time to 5 h. The molecular weight of PLLA product also increased to 68000 g/moi over the same period. An increase in monomer concentration resulted in a higher molecular weight, up to 144000 g/mol and 97% of monomer conversion. Raising the reaction pressure from 130 to 240 bar also resulted in an increased monomer conversion and molecular weight. To increase heat resistivity of PLLA, methanol treatment and heat-vacuum methods were evaluated. Both of them successfully improved the heat resistivity property of PLLA.

• Journal of Microbiology and Biotechnology
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• v.33 no.11
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• pp.1403-1411
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• 2023

Carbon dioxide (CO₂) is the most abundant component of greenhouse gases (GHGs) and directly creates environmental issues such as global warming and climate change. Carbon capture and storage have been proposed mainly to solve the problem of increasing CO₂ concentration in the atmosphere; however, more emphasis has recently been placed on its use. Among the many methods of using CO₂, one of the key environmentally friendly technologies involves biologically converting CO₂ into other organic substances such as biofuels, chemicals, and biomass via various metabolic pathways. Although an efficient biocatalyst for industrial applications has not yet been developed, biological CO₂ conversion is the needed direction. To this end, this review briefly summarizes seven known natural CO₂ fixation pathways according to carbon number and describes recent studies in which natural CO₂ assimilation systems have been applied to heterogeneous in vivo and in vitro systems. In addition, studies on the production of methanol through the reduction of CO₂ are introduced. The importance of redox cofactors, which are often overlooked in the CO₂ assimilation reaction by enzymes, is presented; methods for their recycling are proposed. Although more research is needed, biological CO₂ conversion will play an important role in reducing GHG emissions and producing useful substances in terms of resource cycling.

• Preventive Nutrition and Food Science
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• v.14 no.4
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• pp.362-366
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• 2009

To determine the effect of electron-beam irradiation on the contents of polymethoxylated flavones (PMFs) extracts from citrus pomaces (CP), CP was irradiated at 0, 1, 2, or 5 kGy. Methanol extract of the irradiated CP were prepared and the PMF (nobiletin, sinensetin, and tangeretin) content of the extract was determined. Nobiletin and sinensetin of CP extract significantly increased with irradiation dose-dependent. However, electron-beam irradiation decreased the amount of tangeretin in the CP extract. These data suggest that irradiation can liberate phenolic compounds such as nobiletin or sinensetin, but tangeretin might have different pathway of conversion by irradiation. Therefore, irradiation can be a tool to change the composition of PMFs in CP.

• Journal of Photoscience
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• v.12 no.2
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• pp.109-111
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• 2005

It was found that 1,4-diketones such as 1,4-diphenyl-l,4-butanediones containing N,N-dimethylaminophenyl (pDPB) and N,N-dimethylaminonaphthyl (nDPB) at C2 are converted into 3-(4-dimethylaminoaryl)-1-phenylpropan-lones (pPPA and nPPA) by treatment with $Ca(OH)_2$ in methanol, which was easily oxidized to enone, i.e., 3-(4-dimethylaminophenyl)-l-phenylpropenones (pPPE and nPPE), when treated with 2,3-dichloro-5,6-dicyano-l,4-benzoquinone (DDQ) in dichloromethane.

• Journal of the Korean Wood Science and Technology
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• v.44 no.2
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• pp.218-230
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• 2016

The effect of steam explosion coupled with alkali (1% sodium hydroxide, 1% potassium hydroxide and 15% sodium carbonate) or organosolv solvent (85% methanol, 70% ethanol and dioxane) on the production of sugar, changes in the chemical composition of M. sinensis were evaluated. The steam explosion coupled with 1% potassium hydroxide and dioxane were better as compared with other treatments based on the removals of acid insoluble lignin, and about 89.0% and 85.4%. Enzymatic hydrolysis of steam explosion with 1% potassium hydroxide and dioxane treated M. sinensis, gave a 98.0% and 96.5% of glucose conversion, respectively. These results suggested that pretreatment of M. sinensis with either potassium hydroxide or dioxane could be a promising pretreatment method for glucose production.