• Analytical Science and Technology
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• v.30 no.4
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• pp.205-212
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• 2017

Rice endosperm, the portion that remains after milling, is the part of the rice seed that is primarily consumed as a source of nutrients. There have been many studies on polysaccharides, such as hemicellulose, cellulose, and pectins, derived from the cell walls of various plant groups. It has been reported that the acidic polysaccharide fractions, which contain water-soluble pectins that have been shown to have pharmacological effects in vivo and in vitro, have common chemical structures that include galacturonic acid polymers, rhamnose, arabinose, and galactose. However, few studies have been conducted on the acidic polysaccharides contained in the endosperm of rice. In this study, we quantitatively compared the differences in the acidic polysaccharide contents from samples from two of the main varieties of rice consumed as staple foods, japonica and indica, using a colorimetric method. Rice samples were collected from 39 different regions in Korea, China, Thailand and Vietnam. Acidic polysaccharide fractions were obtained by precipitation of the alcohol-insoluble residue (AIR) and enzyme treatment of each sample. The total amount of carbohydrates and uronic acid in each acidic polysaccharide fraction were measured using the phenol-sulfuric acid method and the carbazole-sulfuric acid method, respectively. The differences in the total polysaccharide contents in the acidic polysaccharide fractions were not statistically significant (p = 0.07), but the uronic acid contents were significantly different between the two groups (p = 0.04).

• Applied Chemistry for Engineering
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• v.28 no.5
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• pp.539-546
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• 2017

In this study, an outstanding anion exchange chemical filter was prepared for acidic gas removal. Commercial anion exchange resin was attached to polyurethane (PU) foam by using different types of pressure sensitive adhesive (PSA). The water and chemical resistance and also adhesive elongation were investigated. Also, the behavior of HCl and HF adsorption was evaluated as functions of the initial concentration and flow rate. ATE-701, AT-4000C and HCA-1000 showed 900, 1,500% and 2,400% of the elongation, respectively. It was confirmed that the desorption ratio of HCA-1000 was less than 6% and had excellent durability in water and chemical resistance tests. The adsorption occurred faster as the concentration and flow rate of HCl and HF increased. But 100% adsorption equilibrium occurred after 110 minutes, regardless of the concentration and flow rate. In addition, SEM morphology showed that the adhesive was uniformly dispersed, while the porous structure of the ion exchange resin was maintained, and the chemical filter exhibited excellent durability for the adsorption/desorption process.

• Economic and Environmental Geology
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• v.9 no.2
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• pp.85-106
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• 1976

The Bulgugsa acidic igneous rocks of the late Cretaceous age are largely distributed in Busan area, which is located in the southeastern corner of the Korean Peninsula. These igneous rocks comprise in ascending order, felsite, dacitic-rhyolitic welded tuffs, granite porphyry and granitic rocks. The former three members represent the early phase of volcanic activities, so that they are named as Jangsan volcanic rocks. The granitic rocks consist of granodiorite, hornblende biotite granite, Kumjongsan granite, fine grained granite, and Daebyen granite, represent the late phase of igneous activities. The Kumjongsan grainte, the largest pluton of the granitic mass, emplaced between two great vertical faults trending NNE. New chemical analyses of 33 rock samples of these acidic rocks are given. Their chemical compositions are generally similar to those of the late Mesozoic acidic igneous rocks of the northern Ashio mountains, and C-Zone granite group of the Ogcheon geosyncline, with their characteristic variation trends of several oxides. Their chemical compositions also show that $Al_2O_3$ is high value, and differentiation index is high, too. Systematically developing joints in Kumjungsan granite are divisible into two types at least. One is the NS-N $20^{\circ}E$ trendirig, $85^{\circ}{\sim}90^{\circ}$ dipping type of joint system which coincides with the trends of distribution of the granite mass and the dikes intruding this granite. Joints of this type may be cooling joints generated as tension cracks. The other is the $N60^{\circ}{\sim}70^{\circ}W$ or $N40^{\circ}{\sim}60^{\circ}E$ trending type of joint systems. It is considered that. joints belonging to this type may be shear joint occurring under the state of south-north tectonic couple acting at the east and west side of the granite mass. Igneous activities of the the Bulgugsa acidic igneous rocks in Busan area was taken place as. follows, formation of the magma reservoir, eruption and intrusion of felsite, consolidation of vents. and increasing vapor pressure in magma reservoir, eruption of pyroclastic flows, caldera collapse, intrusion of granite porphyry, and intrusion of granitic rocks at the latest stage.

• Bulletin of the Korean Chemical Society
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• v.31 no.10
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• pp.2973-2979
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• 2010

The newly synthesized homogeneous chiral Co(III) salen complexes were anchored non-covalently on the acidic sites of mesoporous Al-SBA-15. The Bronsted and Lewis acidic sites are attributed to the immobilization of fluorine functionalized chiral salen complexes on the supports. XRD, BET, TEM, FT-IR and ESCA (XPS) analyses were performed to characterize the property of support, and the structure of new homogeneous and heterogeneous chiral Co salen catalyst. The homogeneous and heterogeneous catalysts could be applied in asymmetric ring opening of epichlorohydrine (ECH) by water. They showed very high enantioselectivity and a good yield up to 99% in the catalytic synthesis of optically active products.

• Korean Chemical Engineering Research
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• v.48 no.5
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• pp.643-648
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• 2010

Production of biodiesel from soybean oil catalyzed by Lewis acidic ionic liquids(ILs) containing metal chloride salts was investigated in this study. Metal chloride salts, such as $SnCl_2$, $ZnCl_2$, $AlCl_3$, $FeCl_3$ and CuCl, were screened for oil transesterification in the range of 363-423 K. Among these metal chlorides, tin chloride showed particularly high catalytic property for the oil transesterification. Similarly, among these Lewis acidic ionic liquid catalysts, $[Me_3NC_2H_4OH]Cl-2SnCl_2$ resulted in a high fatty acid methyl esters(FAMEs) content of 91.1% under the following reaction conditions: 403 K, 14 h, and a molar ratio of 1:12:0.9 (oil:methanol:catalyst). Unlike the pure tin chloride catalysts, Lewis acidic ILs containing tin chloride $[Me_3NC_2H_4OH]Cl-2SnCl_2$ catalyst could be recycled up to five times without any significant loss of activity by separating from the FAMEs with simple decantation. The Lewis acidity and high moisture-stability of this catalyst appeared to be responsible for the excellent catalytic performance. The effects of reaction time and the molar ratio of methanol/catalyst to oil on the FAMEs production were also studied in this work.

• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.743-748
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• 2013

The temperature dependence of the partition coefficients of a neuropeptide, substance P (SP), in isotropic acidic bicelles was investigated by using a pulsed field gradient nuclear magnetic resonance diffusion technique. The addition of negatively charged dimyristoylphosphatidylserine to the neutral bicelle changed the SP partitioning a little, which implies that the hydrophobic interaction between the hydrophobic residues of SP and the acyl chains of lipid molecules is the major interaction while the electrostatic interaction is minor in SP binding in a lipid membrane. From the temperature dependence of the partition coefficients, thermodynamic functions were calculated. The partitioning of SP into the acidic bicelles is enthalpy-driven, as it is for small unilamellar vesicles and dodecylphosphocholine micelles, while peptide partitioning into a large unilamellar vesicle is entropy-driven. This may mean that the size of lipid membranes is a more important factor for peptide binding than the surface curvature and surface charge density.

• Bulletin of the Korean Chemical Society
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• v.32 no.3
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• pp.787-792
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• 2011

Under mild conditions and without any additional organic solvent, synthesis of carbamatoalkyl naphthols could be carried out in the present of two halogen-free Br${\phi}$nsted acidic ionic liquids, 3-methyl-1-(4-sulfonic acid)butylimidazolium hydrogen sulfate and N-(4-sulfonic acid)butylpyridinium hydrogen sulfate. A wide range of aromatic aldehydes easily undergo condensation with $\beta$-naphthol and methyl or benzyl carbamate to afford the desired products of good purity in excellent yields. The present methodology offers several advantages such as a simple procedure with an easy work-up, short reaction times, and excellent yields. The catalysts could be recycled and reused for several times without substantial reduction in their catalytic activities.

• Journal of the Korean Chemical Society
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• v.10 no.4
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• pp.161-165
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• 1966

The critical concentrations of ${\alpha}$-amino capric acid for micelle formation have been determined by the surface tension measurements in both acidic and alkaline solutions, and also by the dye titration using Rhodamine B in alkaline solutions. The critical micelle concentrations obtained by the two methods show the good agreements within experimental errors. Since ${\alpha}$-amino acid is an ampholyte, it may aggregate to form the micelles in both more acidic and basic media than its isoelectric point. It is found that the basic media are rather preferable for the micelle formation than the acidic media. The effect of gegen ions upon the critical concentration for micelle formation in alkaline media is similar to that expected from the salt effect on the CMC (Critical Micelle Concentration).

• Bulletin of the Korean Chemical Society
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• v.15 no.6
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• pp.497-502
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• 1994

A new chiral stationary phase (CSP) for the liquid chromatographic resolution of enantiomers was prepared from (S)-naproxen and 3,5-dinitroaniline. The 6-alkoxy-2-naphthyl group of the CSP was presumed to act as a ${\pi}$-basic interaction site for resolving ${\pi}$-acidic racemates while the 3,5-dinitroanilide group of the CSP was presumed to play a role as a ${\pi}$-acidic interaction site for resolving ${\pi}$-basic racemates. From the chromatographic resolution trends of N-alkylamide derivatives of ${\alpha}$-arylalkylamines on the CSP prepared, the chiral recognition mode involving the intercalation of the amide alkyl chain of the less retained enantiomers between the connecting tethers of the CSP was proposed.

• Bulletin of the Korean Chemical Society
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• v.17 no.12
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• pp.1117-1123
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• 1996

Chiral recognition models for resolving π-basic N-acyl-α-(1-naphthyl)alkylamines and π-acidic N-(3,5-dinitrobenzoyl)-α-amino alkyl esters on a (S)-tyrosine-derived chiral stationary phase (CSP) containing both π-basic and π-acidic interaction site have been proposed. In the models, the CSP was supposed to interact with the analytes through the π-π interaction between the 3,5-dinitrophenyl or the 3,5-dimethylphenyl group of the CSP and the 1-naphthyl or the 3,5-dinitrophenyl group of the analyte, and through the hydrogen bonding interaction between the appropriate N-H hydrogen of the CSP and the appropriate carbonyl oxygen of the analyte. In this instance, the alkyl substituent of the pertinent enantiomer of the analyte was found to intercalate between the adjacent strands of the bonded phase and consequently control the trends of the separation factors.