• Korean Journal of Food Science and Technology
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• v.22 no.5
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• pp.549-554
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• 1990

Glycosidically bound fraction was separated from apricot by Amberlite XAD-2 adsorption and eluted with methanol. Aglycones were liberated from the bound fraction by enzymatic hydrolysis, acid hydrolysis or by means of simultaneous distillation-extraction at pH 3.0. A total of 40 components were identified in three bound volatile fractions. Besides linalool oxide, linalool. ${\alpha}-terpineol$, nerol, geraniol, benzyl alcohol and 2-phenylethyl alcohol, previously reported as glycosidically bound volatiles, the following components were identified for the first time as glycosidically bound volatiles in apricot: 2,6-dimethyl-3,7-octadiene-2,6-diol , 3.7-dimethyl-1,5-octadiene-3,7-diol, (E)- and (Z)-2.6-dimethyl-2,7-octadiene-1,6-diol, $3,4-didehydro-{\beta}-ionol,\;3-oxo-{\alpha}-ionol$, $3-hydroxy-7,8-dihydro-{\beta}-ionol,\;3-oxo-7,8-dihydro-{\alpha}-ionol ,\;3-hydroxy-{\beta}-ionone$, eugenol, 4-hydroxyethylphenyl acetate and 2,3-dihydrobenzofuran.

• Elastomers and Composites
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• v.44 no.4
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• pp.447-454
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• 2009

We synthesized polyester-diol containing Cloisite 30B which is exfoliated during the synthesis. First, esterification was conducted with excess adipic acids and two 2-hydroxyethyl groups of the tertiary ammonium tethered to Cloisite 30B silicate layer. Due to the small molecular size of adipic acid ($d{\approx}3.0\;{\AA}$, $L{\approx}9.3\;{\AA}$), it penetrated into the interlayer of Cloisite 30B, reacted with the 2-hydroxyethyl groups, and produced the tertiary ammonium that has the two ethyl-ester adipic acid groups, one methyl group, and one hydrogenated alkyl group. Through the esterification, the molecular size of the tertiary ammonium increased and as the result, the basal space of Cloisite 30B increased from $18.4\;{\AA}$ to more than $58.3\;{\AA}$. The produced ethyl-ester adipic acid and unreacted adipic acid reacted with excess diethylene glycol ([COOH]/[OH]${\approx}0.6$) to be polyester-diol. The COOH conversion calculated from the acid value of the reactant mixture was 94%. The number average molecular weight and PDI of the produced polyester-diol were 830 g/mol and 1.2, respectively.

• Journal of the Korean Chemical Society
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• v.51 no.4
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• pp.392-397
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• 2007

• Proceedings of the Korean Ceranic Society Conference
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• 2000.10a
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• pp.177.1-177
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• 2000

• Microbiology and Biotechnology Letters
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• v.35 no.4
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• pp.285-291
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• 2007

Enantioconvergent hydrolysis process for the preparation of chiral diol from racemic epoxides by using the recombinant Caulobacter crescentus epoxide hydrolase (CcEH) in Escherichia coli BL21 (DE3) was optimized. For the optimization, the effects of detergent, temperature and product inhibition on the enantiopurity and the yield of diol were investigated. (R)-phenyl-1,2-ethanediol with 92% enantiomeric excess and 56% yield from 20 mM racemic styrene oxide was obtained by using the recombinant CcEH at the optimal condition of $10^{\circ}C$ and the addition of 2% (w/v) Tween 80. At 50 mM racemic styrene oxide was used as a substrate, (R)-phenyl-1,2-ethanediol was obtained with 87% enantiomeric excess and 77% yield. Racemic phenyl-1,2-ethanediol, (R)-phenyl-1,2-ethanediol and (S)-phenyl-1,2-ethanediol dramatically inhibited the hydrolytic activity of the recombinant CcEH. These results suggested that another EH with the regioselectivity on ${\beta}$-position of (R)-enantiomer and without feedback inhibition by products would be needed as the partner EH of C. crescentus EH.

• Journal of the Korean Chemical Society
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• v.56 no.6
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• pp.720-724
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• 2012

Under pseudo-first order conditions, the monomeric species of Cr(VI) was found to be kinetically active in the absence of phenanthroline (phen) whereas in the phen-promoted path, the Cr(VI)-phen complex undergoes a nucleophilic attack by etane-1,2-diol to form a ternary complex which subsequently experience a redox decomposition leading to hydroxy ethanal and Cr(III)-phen complex. The effect of the cationic surfactant (CPC), anionic surfactant (SDS) and neutral surfactant (TX-100) on the unpromoted and phen-promoted path have been studied. Micellar effects have been explained by considering the preferential partitioning of reactants between the micellar and aqueous phase. Combination of TX-100 and phenanthroline will be the ideal for chromic acid oxidation of ethane-1,2-diol in aqueous media.

• Journal of Environmental Science International
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• v.16 no.8
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• pp.891-896
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• 2007

Waterborne polyurethane dispersions (WPUD) were prepared by poly(ethylene glycol) adipate as the polyester type, ${\alpha},{\omega}-hydroxyalkyl$ terminated polydimethylsiloxane (PDMS-diol) as the polysiloxane type, hexamethylene diisocyanate, and isophorone diisocyanate, dimethylol propionic acid. The effects of PDMS-diol contents on the particle size, thermal and surface properties of WPUD were investigated. The structures of the synthesized WPUD were confirmed using by FT-IR. The surface, thermal and mechanical properties were investigated by measuring the contact angles, DSC, TGA and UTM. As PDMS-diol contents increased, the particle size, the contact angle, and the elongation was increased, while the tensile strength was decreased. Also the thermal stabilities of the synthesised WPUD were increased as PDMS-diol contents increased.

• The Journal of Natural Sciences
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• v.8 no.2
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• pp.27-34
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• 1996

The phagocytosis and chemotaxis of murine macrophages after treated with saponin fractions are investigated. Phagocytic appearance against yeast was photographed by dying with Wright-Giemsa. Phagocytic activity of peritoneal macrophage was invreased in diol saponin treatment by 48% and was decreased in total saponin treatment by 35%. The ingestion of alveolar macrophage was increased by 50% maximally. Peritoneal chemotactic activity was shown in 17% increases and only diol saponin had effect in alveolar macrophage by 16%. According to SDS-PAGE method the contents of actin did not show any alterations.

• Elastomers and Composites
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• v.57 no.1
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• pp.13-19
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• 2022

Polycarbonate diol-based waterborne polyurethane (WPU) was prepared by prepolymer mixing process. The prepolymer mixture contained the polycarbonate diol, isophorone diisocyanate (IPDI), dimethylol propionic acid, triethylamine, and ethylenediamine (EDA). The NCO/OH ratio in the prepolymer was adjusted by controlling the molar ratio of IPDI, and its effects on the properties of WPU were studied. The structure of WPU was characterized by fourier transform infrared spectroscopy. The average particle size increased and viscosity decreased with increasing NCO/OH ratio and EDA content in WPU. The reduced phase separation between soft and hard segments increased glass transition temperature. The reduction in the thermal decomposition temperature could be attributed to the low bond energy of urethane and urea groups, which constituted the hard segment. Additionally, the polyurethane chain mobility was restricted, elongation decreased, and tensile strength increased. The hydrogen bond between the hard segments formed a dense structure that hindered water absorption.

• Korean Journal of Food Science and Technology
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• v.35 no.3
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• pp.399-404
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• 2003

Aliphatic polyester, especially poly(butylene adipate)(PBA), is quite biodegradable and one of the most promising polymer materials to be commercialized. Bis(4-hydroxybutyl) adipate (BHBA) formation stage is the first principal process in the production of PBA from adipic acid (AA) and 1,4-butane diol (BD). In this study, we investigated for the effective production of Bis(4-hydroxybutyl) adipate (BHBA), effects of molar ratio of adipic acid (AA) to 1,4-butane diol (BD), catalyst (tetrabutyl titanate, TBT) concentration, and temperature on the reaction rate of esterification between AA and BD were investigated. Initial reaction rate of the esterification decreased with increasing molar ratio of AA to BD and reaction temperature, whereas reaction constant increased with increase in catalyst-concentration. Activation energy values for catalyzed and uncatalyzed esterifications were 198.5 and 94.8 kJ/mol, respectively.