• Journal of the Korean Chemical Society
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• v.29 no.2
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• pp.178-182
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• 1985

The purpose of this study was to develop a separation method of Zn(II), Cu(II) and Mg(II), by ion exchange chromatography using cation exchange resion (Dowex 50w${\times}$8, 80-100 mesh) and anion exchange (Amberlite IRA-400). Ion exchange resions were packed into 25 ${\times}$ 2cm ID column and flow rate was controlled to 0.30 ml/min. Good eluents for separation of nonferrous metal ions such as Zn(II), Cu(II), Mg(II) were as follow: 0.5M $NaNO_3$ (pH 3.1), 0.2~0.5M HCl + 50~60% Acetone, and 1M HAc + 0.1M NaAcf(pH 3.7) aqueous solution. The mixed solution of 0.1M NaAc(pH 3.7), 0.5M HCl + 50% Acetone were found to be the best eluent for step elution. Analysis of metals were determined by atomic absorption spectrophotometer. In addition, separated Zn(II) fraction was obtained by eluted with 0.12N HCl and 1.5N $NH_4OH$ aqueous solution. This solution was titrated by the E. D. T. A.

• Journal of the Korean Chemical Society
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• v.17 no.6
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• pp.416-423
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• 1973

Formation of the complexes of alkaline earth metal ions with malonate and o-phthalate ions in aqueous, ethanol-water and acetone-water solutions (20% by volume) was studied at room temperature by the equilibrium ion exchange technique. This technique involved the measurements of distribution of radioactivity between cation exchange resin(Ion Exchange Resin CGC 241) and solution phases after the radioactive metal ions were equilibriated with the cation exchange resin in the presence of malonate or o-phthalate ions of varying concentrations. The pH of the solutions was controlled to 7.2~7.5, and the ionic strength of the solutions was kept at 0.10~0.11. The results of the present study indicated that the alkaline earth metal ions formed one-to-one complexes with the dibasic organic acids in all solvent systems examined. The present study showed that the relative stabilities of the complexes increased in the order: $Ba^{++}\;<\;Sr^{++}\;<\;Ca^{++}$ complexes. It was also observed that the relative tendency of the o-phthalate ion for the complex formation was somewhat greater than that of malonate ion in each solvent system. Furthermore, it was noted that the complexes were formed more readily in the mixed solvent than in the aqueous solution.

• Journal of the Korean Chemical Society
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• v.18 no.1
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• pp.31-39
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• 1974

Solutions of $Mn^{++}, Co^{++} and Zn^{++}$ were mixed with various dibasic organic acids in the presence of cation exchange resin at room temperature. The distribution ratios of the metal ions between resin and solution were measured, using radioactive metal ions as tracer. From the observed variation of the distribution ratios with acid anion concentrations, it was concluded that $Mn^{++}, Co^{++}$ and $Zn^{++}$ formed one-to-one complexes with succinate, malonate, o-phthalate and tartrate ions in aqueous, 20 % ethanol-water and 20 % acetone-water solutions. The results of the present investigation indicated that the relative stabilities of the complexes increased in the order: $Mn^{++} < Co^{++} < Zn^{++} complexes, Succinate < malonate < o-phthalate < tartrate complexes, Aqueous < mixed solvent systems.$

• Bulletin of the Korean Chemical Society
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• v.15 no.2
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• pp.154-161
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• 1994

Studies have been conducted to explore single electron transfer (SET) induced photocyclization reactions of N-(trimethylsilylmethylthioalkyl)phthalimides (alkyl=ethyl, n-propyl, n-butyl, n-pentyl, and n-hexyl). Photocyclizations occur in methanol in modest to high yields to produce cyclized products in which phthalimide carbonyl carbon is bonded to the carbon of side chain in place of the trimethylsilyl group. Mechanism for these photocyclizations involving intramolecular SET from sulfur in the ${\alpha}$-silylmethylthioalkyl groups to the singlet excited state phthalimide moieties followed by desilylation of the intermediate ${\alpha}$ -silylmethylthio cation radicals and cyclization by radical coupling is proposed. In contrast, photoreactions of N-(trimethylsilylmethylthioalkyl)phthalimides in acetone follow different reaction routes to produce another cyclized products in which carbon-carbon bond formation takes place between the phthalimide carbonyl carbon and the carbon ${\alpha}$ to silicon and sulfur atoms via triplet carbonyl hydrogen abstraction pathway. The normal singlet SET pathway dominates this triplet process for photoreactions of these substances in methanol while the triplet process dominates the singlet SET pathway for those in acetone. The efficient and regioselective cyclization reactions observed for photolyses in methanol represent synthetically useful processes for construction of medium and large ring heterocyclic compounds.

• Journal of the Korean Chemical Society
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• v.14 no.1
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• pp.65-74
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• 1970

Formation of the complexes of alkaline earths with citrate ions in aqueous, acetone-water and ethanol-water solutions was studied at room temperature by the equilibrium exchange technique. This technique involved the measurements of distribution of radioactivity between cation exchange resin and solution phase after the radioactive metal ions were equilibriated with the cation exchange resin in the presence of citrate ions ($Cit^{3-}$) of varying concentrations. The pH of the solutions was controlled to 7.2-7.5, and the ionic strength of the solutions was kept at 0.10-0.12. The present study revealed that both barium and strontium ions formed the one to one citrate complexes, $[M Cit]^-$ in all solvent systems examined. It was also observed that calcium ions formed the one to one citrate complex in aqueous solution. In acetone-water and ethanol-water solutions, however, calcium ions were observed to form both one to one and one to two complexes, $[Ca Cit]^-$ and $[Ca\;Cit_2]^{4-}$. The results of the present study indicated also that relative stabilities of the complexes increased in the order; $Ba^{++}\;<\;Sr^{++}\;<\;Ca^{++}$, and in the order of increasing concentration of the organic components in the mixed solvent systems.

• Journal of the Korean Chemical Society
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• v.27 no.2
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• pp.142-149
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• 1983

Reaction of thianthrene cation radical perchlorate (1) with cumene (4), p-chlorocumene (2), and p-nitrocumene (3) hydroperoxides in acetonitrile at room temperature afforded, inter alia, thianthrene as a common product and 5-(4'-hydroxyphenyl) thianthrenium perchlorate (5) for 4, 5-(5'-chloro-2'-hydroxyphenyl) thianthrenium perchlorate (7) and 5-acetonylthianthrenium perchlorate (6) for 2 and 6 for 3, respectively. Stoichiometry of these reactions showed that 2 moles of 1 gave rise to 1mole of thianthrene and 1 mole of thianthrenium salt (or salts). Nucleophilic reactivity to 1 was found to be in the order of phenol > > p-chlorophenol ${\sim}$ acetone > > p-nitrophenol. Apart from acid-catalyzed heterolytic decomposition of hydroperoxides, small amount of homolytic decomposition products were found from 3 and 4.

• Journal of the Korean Chemical Society
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• v.31 no.1
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• pp.37-44
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• 1987

The rates of solvolysis of $cis-[Co(en)_2Cl_2]^+$ complex have been investigated using spectrophotometric method at various pressures up to 1500 bar in several binary-aqueous mixtures(water-methyl alcohol, water-acetone, water-isopropyl alcohol and water-ethylene glycol). The activation volumes obtained from the pressure effect on rate constants were 1.13∼4.44 cm3mole-1 for methyl alcohol, 1.13∼3.59$cm^3mole^{-1}$ for acetone, 0.82∼3.44$cm^3mole^{-1}$ for isopropyl alcohol and 1.13∼2.68cm3mole-1 for ethylene glycol. In case of water-methyl alcohol, in addition to, the rates of solvolysis of this complex were determined in the presence of Fe(Ⅱ) ion and the activation volumes were -0.56∼1.59cm3mole$^{-1}$. The rates of solvolysis of this complex were analyzed by comparing with the results obtained from activation volumes and free energy cycle.

• Journal of the Korean Chemical Society
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• v.17 no.4
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• pp.247-255
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• 1973

The self supported film specimen of Wyoming montmorillonite as a layer silicate saturated by cations,$Li^{+},\;Na^{+},\;K^{+},\;Ca^{2+},\;Ni^{2+},\;Al^{3+}$and$F^{3+}$ were allowed to contact acetone, methyl-ethyl ketone and diethyl ketone within the heatable gas cell. The i.r. spectra between $4000{\sim}1200cm^{-1}$ at different pressures of adsorbates indicated bond formation through carbonyl oxygen. Two types of carbonyl bond shift with maxima at $1713cm^{-1}$ and $1690cm^{-1}$ are attributed as coordinate bond formation of carbonyl with either surface hydroxyl or cationic hydroxyl group. The intensity of the vOH was analyzed and resonance form of cationic hydroxyl was proposed as an adsorption site. The tendency to form coordinate bond was in good agreement with calculated formal charge of carbonyl oxygen in an increasing order, acetone < methyl-ethyl ketone < diethyl ketone. As an additional mechanism of adsorption, weak hydrogen bonding of methyl hydrogen with surface oxygen was observed.

• Journal of Life Science
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• v.20 no.8
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• pp.1235-1240
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• 2010

Natural compounds have been studied to substitute synthetic antioxidants. In this study, the anti-oxidant activity of 70% acetone extracts from the Vaccinium oldhami fruit was investigated for utilization as ingredients for the cosmetic and bio-industries. Anti-oxidant activity was determined by determining total polyphenolic content, electron donating ability, nitric oxide (NO) radical scavenging activity, $ABTS{\cdot}^+$ cation radical scavenging activity and hydrogen peroxide scavenging activity. The polyphenolic content of 70% acetone extracts of the Vaccinium oldhami fruit was 55.972 mg TAE/g. In electron donating activity, 70% acetone extracts of the Vaccinium oldhami fruit showed an effect of 93.9%, which was similar to BHA effect at a concentration of 500 ${\mu}g/ml$. In the NO radical scavenging ability, 70% acetone extracts of the Vaccinium oldhami fruit showed 60% at 500 ${\mu}g/ml$. $ABTS{\cdot}^+$ cation radical scavenging activity of the Vaccinium oldhami fruit at a concentration of 1000 ${\mu}g/ml$ was 75.7%. Also, hydrogen peroxide scavenging activity of 70% acetone extracts showed 80.8% at 100 ${\mu}g/ml$, whichwas higher than BHA. In the natural compound market, the most important factors are the ability to obtain high effects of a material in low concentrations and a long-lasting supply. The Vaccinium oldhami fruit can be harvested every year - this fulfills one of the requirements. From these results, we can confirm that the Vaccinium oldhami fruit has anti-oxidant abilities and has potential as a natural anti-oxidant agent to be utilized in the cosmeceutical and bio-industries.

• Microbiology and Biotechnology Letters
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• v.25 no.2
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• pp.189-196
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• 1997

A producer of inhibitor against ${\beta}-glucosidase$ of Penicillium sp.-L4 was screened from Actinomycetes, and the isolated strain was identified as Streptomyces sp. The inhibitor produced was very stable against heat, acidic and alkaline conditions, proteolytic and amylolytic enzymes. The inhibotor was purified from culture broth through activated carbon treatment, ultrafiltration, anion and cation exchange, activated carbon columm, acetone precipitation and preparative HPLC. It showed inhibitory activities against a variety of dissacharide hydrolyzing enzymes produced by P.sp.-L4, and the mode of inhibition was competitive. Its structure and molecular formular was elucidated by IR, $^1H\;and\;^{13}C$ NMR and FAB/Mass spectrometry, which was identified as 1-deoxynojirimycin (dNM). dNM showed inhibitory effects on the cell growth and hydrolytic enzyme action of P.sp.-L4 on agar plate and infected lemon peel.