• Journal of the Korean Chemical Society
• /
• v.24 no.2
• /
• pp.155-166
• /
• 1980

3-(N-Carbonylpyrrolidone)-propanoic acid potassium-salt and 3-(N-carbonylpyrrolidone)propenoic acid potassium-salt were synthesized by the reaction of 2-pyrrolidone potassium-salt with succinic anhydride and maleic anhydride in acetone and in acetone and in benzene. The anionic polymerization of 2-pyrrolidone with 3-(N-carbonylpyrrolidone)-propanoic acid potassium-salt or 3-(N-carbonylpyrrolidone)-propenoic acid potassium-salt as an initiator and potassium hydroxide as a catalyst was studied. It was found that 2.0 and 1.0 mole %, concentration of catalyst and initiator, and temperature of $50^{\circ}C$ was the optimum condition obtaining highest conversion and viscosity of polymer. The inherent viscosity of nylon 4 was measured to be 1.2 dl/g and 2.3 dl/g.

• Journal of the Korean Society of Tobacco Science
• /
• v.28 no.2
• /
• pp.75-82
• /
• 2006

This study was carried out to investigate the changes of free sugars, non-volatile organic and fatty acids in flue-cured leaf tobacco during aging. The threshed leaf tobacco(B1O and C1L) produced in 2002 crop year was aged for 21 month in warehouse of Oc-Cheon Leaf Tobacco Processing Factory. The leaf tobacco were sampled at three month intervals for analysis of free sugars, non-volatile organic and fatty acids. The major free sugars of flue-cured were glucose and fructose regardless of tobacco grades. After aging period of 21 months, the contents of glucose and fructose showed a tendency to slightly decrease, and there was no appreciable change in the contents of sucrose in B1O and C1L grades. The major compound of non-volatile organic acid and fatty acid were malic, oxalic and citric, linolenic, linoleic and palmitic acid regardless of tobacco grade. After aging period of 21 months, the contents of malic, malonic, oxalic and fumaric acid showed a tendency to slightly decrease, whereas succinic acid was slightly increased, and maleic acid was not changed in B1O and C1L grades. The decreases in fatty acid contents in B1O and C1L grade tobacco loaves after 21 month aging were 16.5% and 9.8%, respectively. The decreases in linolenic acid contents in two grades were the highest, showing 22.1% and 12.0% reduction after 21 month aging.

• Food Science of Animal Resources
• /
• v.37 no.4
• /
• pp.552-560
• /
• 2017

This study aimed to evaluate the quality characteristics of Tteokgalbi with 1% (w/w) black rice bran only (T1), or with black rice bran and one of the following four types of organic acid: ascorbic acid (T2), citric acid (T3), tartaric acid (T4), or maleic acid (T5) as a substitute for caramel colorant. Tteokgalbi with only black rice bran showed the highest (p<0.05) values of moisture content and water holding capacity (WHC), while there were no significant differences in protein content, fat content, ash content, and thiobarbituric acid reactive substance (TBARS) values in treatments and controls (p>0.05). All the treated samples with any one of the four organic acids showed lower pH than controls (p<0.05). The lightness and redness of Tteokgalbi treated with any one of the four organic acids and black rice bran were higher than those of T1. The volatile basic nitrogen (VBN) values of T4 and T5 were higher than those of the other treatments (p<0.05). With regards to sensory characteristics, T1 and T2 showed overall acceptability similar to that of the controls (p>0.05). The results reported in this study show that Tteokgalbi with black rice bran and any one of the four organic acids listed above not only improved quality characteristics in cooking loss, WHC, lipid oxidation but also could successfully replace the synthetic caramel colorant. Overall, the most satisfactory results were obtained by adding black rice bran and ascorbic acid.

• Journal of the Korean Chemical Society
• /
• v.53 no.3
• /
• pp.308-324
• /
• 2009

The present work is devoted to study the interaction of $\beta$-aroylacrylic acid derivative (3) with malononitrile in (DMF) in the presence of piperidine and/or ammonium acetate, then using the formed compounds as starting materials for synthesizing fused and isolated heterocyclic systems. It has been established that the $\beta$-aroylacrylic acid (3) reacts with malononitrile in (DMF) in the presence of piperidine as a catalyst with the formation of 4H-pyran derivative (4). By changing the catalyst into ammonium acetate, pyridine derivative (5) has been obtained. Also the N-maleamic acid derivatives (19) and (27) have been synthesized via the interaction of (4) and (5) with maleic anhydride. The purpose of this step is to study the behavior of the formed maleamic acid derivatives – as analogies of $\beta$-aroylacrylic acids – towards different active methylene compounds under Michael addition reaction.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.21 no.2
• /
• pp.195-200
• /
• 1992

Rhizopus oryzae CJ-2114 was selected for its strong polygalacturonase activity among various strains of mold found in soil. The optimum pH for the enzyme activity was 4.0 and optimum temperature was 4$0^{\circ}C$. The activation energy for the polygalacturonase was calculated by Arrhenius equation was 2.048㎉/㏖. The reaction of this enzyme followed typical Michaelis-Menten kinetics with the Km value of 54.05mM with the $V_{max}$ of 13.9m mole/min. The enzyme is relatively stable in acidic condition. The activity of polygalactur-onase was inhibited completely by C $u^{2+}$, P $b^{2+}$ and Z $n^{2+}$, $_Mn^{2+}$ at concentration of 1 mM. The enzyme can be inactivated by the treatment with maleic anhydride and iodine. The results indicate the possible involvement of histidine at active site. When polygalacturonase from Rhizopus oryzae CJ-2114 was reacted with poly-galacturonic acid as a substrate mono-, di-, and oligogalacturonic acid were produced at early and mono-, digalacturonic acid produced at late incubation time. time.

• Polymer(Korea)
• /
• v.35 no.6
• /
• pp.593-598
• /
• 2011

The IPA-co-HDO-co-(TPA/MA) copolymers for all-vanadium redox flow battery were synthesized by melt condensation polymerization using isophthalic acid(IPA), 1,6-hexandiol (HDO), terephthalic acid(TPA) and maleic anhydride(MA). The amination of chloromethylated IPA-co- HDO-co-(TPA/MA)(CIHTM) copolymer was carried out using trimethylamine, and the anion exchange membrane was also prepared by UV crosslinking reaction. The structure and thermal stability of IHTM copolymers were confirmed by FTIR, $^1H$ NMR, and TGA analysis. The anion membrane properties such as water uptake, ion exchange capacity, electric resistance and electrical conductivity, were measured by gravimetry, titration and LCR meter. The efficiency of the all-vanadium redox flow battery was analyzed. The ion exchange capacity, electric resistance and electrical conductivity were 1.10 meq/g, $1.98{\Omega}{\cdot}cm^2$, and 0.009 S/cm, respectively. The efficiency of charge-discharge, voltage, and energy for the allvanadium redox flow battery were 96.5, 74.6, 70.0%, respectively.

• Journal of Life Science
• /
• v.20 no.11
• /
• pp.1625-1633
• /
• 2010

This study was carried out to investigate the physicochemical compositions and antioxidative effects of Eriobotrya japonoca Lindl (Loquat). The proximate compositions of the loquat leaf on a dry matter basis were 8.78% moisture content, 6.74% crude protein, 7.87% crude fat, 6.99% crude ash, 43.61% dietary fiber and 26.01% carbohydrate. In analysis of free amino acids, 16 kinds total amino acid components, 17 kinds of components were isolated from loquat. The essential amino acids contained in loquat leaf accounted for 50.15% of total amino acids, while the non-essential amino acids accounted for 49.85%. In analysis of total fatty acids, only 5 kinds of acid were detected: lauric acid, myristic acid, pentadecanoic acid, stearic acid and oleic acid. The contents of vitamin A, vitamin E and vitamin C were 0.039 mg%, 0.096 mg% and 0.575 mg%, respectively. The mineral contents of loquat leaf were greater in order of Zn

• Journal of the Korean Wood Science and Technology
• /
• v.34 no.5
• /
• pp.67-78
• /
• 2006

Modification of polylactic acid (PLA) and 10% maleic anhydride (MAH) with 15% dicumyl peroxide (DCP) based on MAH weight was conducted in the kneader at $160^{\circ}C$ and 30~70 rpm, for 15 min. The resulting MAH-modified PLA (PLA-MA) was then evaluated as a compatibilizer for PLA-wood flour (WF) composites. The FTIR and $^1H$-NMR analysis gave evidence of PLA-MA formation. After kneading and reacting with MAH and DCP, the number (Mn) and the weight average (Mw) molecular weights of PLA decreased as compared to the original PLA. The presence of WF in the composites decreased the tensile strength and several other physical properties. The higher the WF loading resulted in the greater the reduction of tensile strength. An addition of 10% PLA-MA as a compatibilizer to the composites improved the tensile strength and several other physical properties, increased the flow temperature, and decreased the melt viscosity. The improved composite revealed 1.42 times increased in tensile strength but not over PLA alone, and absorbed considerably less water compared to those of the composites free-compatibilizer.

• Elastomers and Composites
• /
• v.51 no.3
• /
• pp.175-180
• /
• 2016

Influence of amino acidic chemical on properties of maleic anhydride-grafted ethylene-propylene-diene terpolymer/zinc oxide (EPDM-g-MAH/ZnO) composites was investigated. 4-Aminosalicylic acid (ASA), 4-amino-2-methoxybenzoic acid (AMBA), 12-aminolauric acid (ALA), and glutamine (Gln) were employed as the amino acidic chemicals. Though small quantity (0.5 phr) of the amino acidic chemical was added to the EPDM-g-MAH/ZnO composite, the properties were notably changed. By adding the amino acidic chemical, the percent crystallinity and apparent crosslink density were reduced. Order of the percent crystallinity was related to that of the $pK_a$ values of amino acidic chemicals. By adding the amino acidic chemical, the basic tensile properties were on the whole improved. The experimental results were explained by the $pK_a$ values of amino acidic chemicals, change of zinc ionomer formation, and interactions between the additive and EPDM-g-MAH chain.

• YAKHAK HOEJI
• /
• v.45 no.4
• /
• pp.357-365
• /
• 2001

The purpose of this study is to investigate the influence of cyclodextrins (CDs) and different acids on the solubility of fluconazole, and o formulate its more concentrated parenteral aqueous solution. Solubility studies of fluconazole with 7-CD, 2-hydroxypropyl-$\beta$-CD (HPCD), sulfobutyl ether $\beta$-CD (SBCD) and dimethyl-$\beta$-CD(DMCD) were performed. The aqueous solubility of fluconazole was measured in different concentrations of different acids with or without addition of CDs. Solubility of fluconazole increased in the rank order of $\beta$-CD$^1$H-NMR studies confirmed the formation of an inclusion complex of fluconazole with HPCD. It was also shown by the NMR studies that the complex formed was a 1:1 complex. Among the different acids used, maleic acid and phosphoric acid increased solubility of fluconazole. The lower the pH of solution is, the more fluconazole dissolved, regardless of acids. Addition of HPCD (50 mM) to acid solutions increased the solubility about two times. New fluconazole injections at a dose of 10 mg/ml could be prepared in aqueous solutions containing 10% HPCD or 15% SBCD. These parenteral solutions did not form any precipitates at 4$^{\circ}C$ and was very stable at elevated temperatures. These results demonstrate that it is possible to develop a parenteral aqueous solution of fluconazole with a smaller injection volume using HPCD or SBCD.