• 한국식품과학회지
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• 제29권3호
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• pp.563-570
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• 1997

GC와 GC-MS를 사용하여 발효 16일 후 탁주술덧의 휘발성 향기성분으로 alcohol 20종, ester 26종, acid 10종, aldehyde 10종, 기타 6종 등 모두 72종이 검출되었다. Aspergillus oryzae구는 68종으로 가장 많았고 재래누룩구의 술덧은 60종으로 적었다. 72종의 휘발성 향기성분 중 54종의 향기성분이 모든 시험 구에서 공통으로 검출되었다. 휘발성 향기성분의 면적비율은 alcohol류 $71.28{\sim}90.23%$, ester류 $0.66{\sim}9.05%$, acid류 $0.20{\sim}0.60%$, aldehyde류 $0.02{\sim}0.09%$순으로 나타났다. 시험구에 따라 차이가 있으나 ethanol, 2-methyl-1-propanol, 3-methyl-1-butanol, 1-hexanol, 2.3-butadienol(D,L), benzeneethanol, acetic acid ethyl ester, succinic acid diethyl ester, butanoic acid monoethyl ester, acetic acid 그리고 benzene acetic acid 4-acetyloxy-3-methyl ethyl ester 등의 면적 비율이 높아 본 실험 탁주 술덧의 휘발성 향기 주성분으로 나타났다. 재래 누룩구는 1-pentanol, hexanoic acid ethyl ester의 면적비율이 다른 시험구보다 높았고, Mucor racemosus 누룩구는 1-hexanol, 1-dodecanol, 1,2-benzenedicarboxylic acid dipropenyl ester, acetic acid가, Rhizopus japonicus 누룩구는 2-methyl-1-propanol, 3-methyl-1-butanol, benzeneethanol, succinic acid diethyl ester, butanoic acid monoethyl ester, 4-methyl benzeneacetic acid phenyl ester, butanoic acid의 면적 비율이 타 시험구보다 각각 높았다. Aspergillus oryzae구는 acetic acid ethyl ester, 3-methyl butanoic acid, pentanoic acid가 높았으며 Aspergillus kawachii구에서는 1-butanol이 높았다.

• Fibers and Polymers
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• 제4권2호
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• pp.59-65
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• 2003

PLA/LPCL/HPCL blends composed of poly(lactic acid) (PLA), low molecular weight poly($\varepsilon$-caprolactone) (LPCL), and high molecular weight poly($\varepsilon$-caprolactone) (HPCL) were prepared by melt blending for bioabsorbable fila-ment sutures. The effects of blend composition and blending time on the ester interchange reaction by alcoholysis in the PLA/LPCL/HPCL blends were studied. Their thermal properties and the miscibility due to the ester interchange reaction were investigated by $^1{H-NMR}$, DSC, X-ray, and UTM analyses. The hydroxyl group contents of LPCL in the blends decreafed by the ester interchange reaction due to alcoholysis. Thus, the copolymer was formed by the ester interchange reaction at $200^{\circ}C$ for 30-60 minutes. The thermal properties of PLA/LPCL/HPCL blends such as melting temperature and heat of fusion decreased with increasing ester interchange reaction levels. However, the miscibility among the three poly-mers was improved greatly by ester interchange reaction. Tensile strength and modulus of PLA/LPCL/HPCL blend fibers increased with increasing HPCL content, while the elongation at break of the blend fibers increased with increasing LPCL content.

• Tribology and Lubricants
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• 제14권3호
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• pp.7-16
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• 1998

The electrorheological (ER) behavior of suspensions in silicone oil of phosphoric ester cellulose powder (average particle size: 17.77 $\mu$m) was investigated at room temperature with electric fields up to 2.5 KV/mm. For development of anhydrous ER suspensions using at wide temperature range, we aimed to know the effect of activation of phosphoric ester cellulose particles on the ER activities. As a first step, the anhydrous ER suspensions mixing with the phosphoric ester cellulose particles which were treated with 2M phosporic acid and 4M urea were measured. After activating the anhydrous ER suspensions at 12$0^{\circ}C$, not only the analysis of dispersing cellulose particles which were reacted by phosphoric ester but also the electrorheological characteristics of ER suspensions such as dielectric constant, current density, electrical conductivity and rheological properties were studied. From the experimental results, the activation of phosphoric ester cellulose particles had an influence on the ER properties of anhydrous ER suspensions. As the activation time went by, the size and number of dispersing particles, the electrical properties and the initial apparent viscosity $(η_0)$ of ER suspensions were increased till the activation time passed 5 hours. Also, it was possible, the electrorheological effect $($\tau$/$\tau$_0)$ of ER fluids was grown by the activation of phosphoric ester cellulose particles.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권3호
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• pp.211-214
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• 2006

Immobilized Candida antarctica lipase was used to catalyze the separation of ketoprofen into its components by means of esterification followed by the enzymatic hydrolysis of the ester product. In this study, ketoprofen underwent esterification to ethanol in the presence of isooctane. When the reaction was complete, 58.3% of the ketoprofen had been transformed into an ester. The ketoprofen remaining in solution after the reaction was complete consisted primarily of its S-enantiomer (83.0%), while the 59.4% of the ketoprofen component of the ester consisted of its R-enantiomer. We then subjected the ester product to enzymatic hydrolysis in the presence of the same enzyme and produced a ketoprofen product rich in the R-enantiomer; 77% of this product consisted of the R-enantiomer when 50% of the ester had been hydrolyzed, and 90% of it consisted of the R-enantiomer when 30% of the ester had been hydrolyzed. By contrast, the R-enantiomer levels only reached approximately 42 and 65%, respectively, when 50 and 30% of the racemic ester was hydrolyzed under the same conditions.

• Journal of Electrical Engineering and Technology
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• 제8권3호
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• pp.524-529
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• 2013

Recently, researchers have become interested in natural ester fluids, as they are an environmentally friendly alternative to mineral oils. Natural ester fluids are a natural resource made from plants; they have higher biodegradability, flash, and fire points, and a greater permittivity compared to conventional mineral oils. However, natural ester fluids also have a higher pour point, viscosity, and water content. These characteristics can hamper circulation and impair the electrical properties of an oil-filled transformer. A large amount of data has been accumulated over the years in regards to mineral insulating oil involving dielectric breakdown voltage and lightning impulse tests. However, natural ester fluids have not had their electrical properties sufficiently characterized. In this paper, we present an investigation into the characteristics of the electrical discharge development in natural ester fluids and in an oil-filled transformer near the pour points. The experiment results show that the electrical properties decreased according to a decrease in the ambient temperature and freezing time. It was found that the pour point and water content of natural ester fluids have a significant effect on the electrical properties.

• 약학회지
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• 제33권4호
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• pp.219-225
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• 1989

2,6-dimethyl-4-(3'-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-methyl 5-(2'-methylthio)ethyl ester methyl iodide salt (7a) was hydrolyzed by treatment with NaOH in aquous EtOH solution to give 2,6-dimethyl-4-(3'-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid mono methyl ester (2b) in 88% yield. By the same procedure, 2,6-dimethyl-4-(3'-nitrophenyl)-1,4-dihydropyridinine-3,5-dicarboxylic acid 3-mono isopropyl ester (2c), 2,6-dimethyl-4-(2'-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-mono methyl ester (2d), 2,6-dimethyl-4-(2',3'-dichlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-mono methyl ester (2e) and 2,6-dimethyl-4-(3'-nitrophenyl)-1,4-dihydropyridin-3,5-dicarboxylic acid (2f) were obtained from the methyl iodide salts in 91-98% yield.

• 약학회지
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• 제33권2호
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• pp.80-86
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• 1989

2,6-Dimethyl-4-(3'-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-methyl 5-(2'-phenylsulfinyl) ethyl ester (10) or 2,6-Dimethyl-4-(2' or 3'-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-alkyl 5-(2-methylsulfonyl) ethyl ester (14a, b, c) were hydrolyzed by treatment with NaOH in aqueous EtOH solution to give 2,6-Dimethyl-4-(3'-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid monomethyl ester (4b), 2,6-Dimethyl-4-(2'-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid monomethyl ester (4c) and 2,6-Dimethyl-4-(2'-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid monoisopropyl ester (4d) in 80 -90% yield. By the same procedure, 2,6-Dimethyl-4-(3'-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3,5-bis (2'-methylsulfonyl) ethyl ester (15) gave 2,6-Dimethyl-4-(3'-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid (4e) in 96% yield.

• Journal of Pharmaceutical Investigation
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• 제36권4호
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• pp.223-229
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• 2006

[ $PGE_1$ ]-ethyl ester intraurethral solutions were prepared in ethanol/propylene glycol mixture with penetration enhancer and viscosity-enhancing agent. The stability of $PGE_1$-ethyl ester in intraurethral solution was investigated at various temperature. Simultaneous determination of $PGE_1$-ethyl ester and $PGE_1$ was performed using a validated HPLC technique. In pentobarbital anesthetized cats, increase in intracavernous pressure(ICP), increase in penile length and duration of erectile response were determined after intraurethral application of $PGE_1$-ethyl ester solutions. $PGE_1$-ethyl ester solutions, when instilled into the eyes of rabbits, produces no noticeable irritation, or slight transient conjunctival irritation. From these results, ocular irritation of this solutions was judged as practically non-irritating. The stability study indicates that the therapeutically effective content in solution is well maintained for 46 weeks or longer when they are stored at $4^{\circ}C$. After intraurethral application of $PGE_1$-ethyl ester, ICP was increased and penile erection was induced. $PGE_1$-ethyl ester intraurethral solutions for erectile dysfunction could be developed and evaluated by employing feline erection model.

• Tribology and Lubricants
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• 제35권2호
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• pp.132-138
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• 2019

In this study, we demonstrate the effects of the acidic properties of montmorillonite (MMT), which is commonly used as a catalyst, on the conversion and selectivity of the dimer acid methyl ester (DAME) synthesis. We synthesize DAME by the dimerization of conjugated linoleic acid methyl ester (CLAME) and oleic acid methyl ester using MMT KSF. Incidentally, trimer acid methyl ester was formed as a by-product during the DAME synthesis. There is a necessity to adequately adjust the strength and quantity of the acid site to control the selectivity of DAME. Therefore, we vary the pH of the MMT acid by using various metal hydroxides. The purpose of this study is to increase the yield of monocyclic dimer acid methyl ester, which is a substance with adequate physical properties for industrial applications (e.g., lubricant and adhesive, etc.), using a heterogeneous catalyst. We report the dimerization of fatty acid methyl ester by using base treated-KSF, and apply it to conjugated soybean oil methyl ester. Then, we transmute the acid site properties of KSF, such as pH of 5 wt.% slurry KSF and various alkali metals (Li, Na, K, Ca). Characterization of base treated-KSF using a pH meter, x-ray diffraction, inductively coupled plasma-atomic emission spectrometer, Brunauer-Emmett-Teller surface analysis, and temperature-programmed desorption. We conduct an analysis of CLAME and DAME using nuclear magnetic resonance spectroscopy, gas chromatography, and gel permeation chromatography. Through these experiments, we demonstrate the effects of the acidic properties of KSF on the conversion and selectivity of the DAME synthesis, and evaluate its industrial potential by application to waste vegetable oil.

• 생명과학회지
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• 제14권1호
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• pp.91-97
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• 2004

앞선 연구의 구조적 특성을 근거로 하여, 한 분자내에 MES 유발경련에 작용하는 cyclicimide의 구조를 포함하면, 그들의 구조가 경련 유발 수용체들에 상호 보완적으로 작용, MES및 PTZ유발 경련에 모두 작용할 수 있는 적용 범위가 넓은 항경련성 화합물이 될 수 있을 것으로 생각하여 N-acyl-$\alpha$-aminosuccinimide 1과 N-acyl-$\alpha$-aminoglutar- imide 2 유도체를 합성하였다. 먼저 (R)-2-benzyloxy carbonylamino-succinic acid 3을 출발 물질로 하여 N-acyl-a-aminosuccinimide 1 유도체인 (R)-Benzoic acid 4-benzyloxycarbonyl-amino-2-oxo-pyrrolidin-l-yl ester 6a, (R)4-nitro-benzoic acid 4-benzyloxycarbon-ylamino-2-oxo-pyrrolidin-1-yl ester 6b, (R)-4-nitro-benzoic acid 4-benzyloxycarbonylamino-2-oxo-pyrrolidin-1-yl ester 6c, 그리고 (R)-propionic acid 4-benzyloxycarbonylamino-2-oxo-pyrrolidin-1-yl ester 64를 합성하였다 또한 (R)-3-car-bobenzyloxy-aminoglutarrnic acid 7를 출발물질로 하여 N-acyl-$\alpha$-aminoglutarimide 2유도체인 (R)-(3-Benzyloxycarbonyl-amino-2,6-dioxo-piperidin-1-yloxy)-acetic acid methyl ester 10a, (R)-(3-benzyloxyarbonylamino-2,6-dioxo-piperidin-1-yloxy)-acetic acid ethyl ester l0b, 그리고 (R)-2-(3-benzylox-ycarbonylanino-2,6-dioxo-piperidin-1-yloxy)-propionic acid methyl ester l0c를 합성하였다. 합성된 화합물 6a, 6b, 6c, 6d, 10a, lOb, l0c에 대한 활성평가는 각 단계별 MES test와 PTZ test의 항경련 활성 시험 방법을 가지고 실험할 예정이다.