• Bulletin of the Korean Chemical Society
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• v.11 no.2
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• pp.99-105
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• 1990

The Gutmann acceptor number(AN), solvatochromic parameters $({\alpha},{\beta}\;and\;{\pi}^{\ast})$ and hydrogen bonding equilibrium constants (KHB) were determined for three binary systems of methanol with 1,2-dimethoxyethane(DME), 1,2-dichloroethane(DCE) and pyridine (PYD). The solvolysis rate constants of t-butyl chloride, bromide and iodide were also determined in the three binary systems. Solvent properties and solvolysis rates have been discussed in the light of various solvent parameters. Solvolysis of t-butyl halides are most conveniently explained by the two-stage mechanism involving ion-pair intermediate with the ion-pair formation for chloride and ion pair dissociation for iodide as rate limiting.

• Bulletin of the Korean Chemical Society
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• v.22 no.8
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• pp.821-826
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• 2001

Solvent sublation has been studied for the separation and determination of trace Zn(Ⅱ) and Pb(Ⅱ) in water samples. A synergy producing method was utilized to improve the efficiency of extraction in the sublation using an ion-pair of metal-naphth oate {M-(Nph)3- } complexes and tetra-n-butylammonium (TBA+ ) ion. After the M-(Nph)3- complexes were formed by adding 1-naphthoic acid to the sample solution, tetra-n-butylammonium bromide was added in the solution to form the ion-pair. And sodium lauryl sulfate (SLS) was added to make the ion-pair hydrophobic. The ion-pairs of the metal complexes were floated and extracted into methylisobutyl ketone (MIBK) from the aqueous solution by bubbling with nitrogen gas in a flotation cell. Metal ions in MIBK solution were measured by graphite furnace-AAS. Experimental conditions were optimized as follow so. After the pH of a 1.0 L water sample was adjusted to 5.0, 6.0 mL of 0.1 M 1-HNph and 10 mL of 0.03 M TBA-bromide were added to the sample to form ion-pairs, and 2.0 mL of 0.2%(w/v) SLS was added to make the ion-pairs hydrophobic. The solution was bubbled with 30 mL/min N2 gas for 5 minutes in a flotation cell. Linear calibration curves were obtained for the determination of Zn(Ⅱ) and Pb(Ⅱ) in several water samples. Reproducible results of showing a relative standard deviation of < 10% and recoveries of 80-100% could be obtained.

• Applied Chemistry for Engineering
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• v.3 no.1
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• pp.100-110
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• 1992

Arylsulfonyl urea derivatives can be easily prepared in good yield by treating amines with arylsulfonyl carbamates in aqueous solution : 1) N-Arylsulfonyl-N'-aryl urea derivatives, 2) N-Arylsulfony-N'-alkyl urea derivatives, 3) N-Arylsulfonyl-N'- heterocyclic urea derivatives. The proposed reaction mechanisms for preparing arylsulfonyl ureas involve formation of an ion-pair conformation by initial acid-base reaction, then formation of a so-called tetrahedral intermediate by nucleophilic addition, followed by an acid-catalyzed elimination of an alkoxide ion and loss of a proton.

• Journal of the Korean Chemical Society
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• v.42 no.4
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• pp.416-421
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• 1998

In the reversed-phase ion-pair high performance liquid chromatographic (RPIP-HPLC) elution behavior of noble metal-thiacrown ether complexes, the effects of the concentration of ion-pairing reagent and kind of ligands were studied. It was found that the less the number of atoms in the ring of the thiacrown ether molecule was, the larger the selectivity was, and the elution mechanism of the complexes was explained due to the formation of ion-pair when the concentration of sodium dodecyl sulfate (SDS) in mobile phase was lower than 10 mM and due to the formation of micelle when the SDS concentration was higher than 10 mM. As a conclusion, separations of the noble metal-thiacrown ether complexes in an optimum separation condition were accomplished successfully and the method was proved to be an useful one for the separation and determination of Ag (Ⅰ) ion in a black-white photographic fixing solution.

• Journal of Pharmaceutical Investigation
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• v.23 no.3
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• pp.41-50
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• 1993

The iontophoretic delivery across rat skin of quaternary ammonium salts (isopropamide: ISP, pyridostigmine: PS), which are positively charged over a wide pH range, was measured ill vitro. The study showed that: (a) iontophoresis significantly enhanced delivery of ISP and PS compared to respective passive transport; (b) delivery of ISP and PS was directly proportional to the applied continuous direct current density over the range of $0-0.69\;mA/cm^2;$ (c) delivery of ISP and PS was also proportional to the drug concentration in the donor compartment over the range of $0-2{\time}l0^{-2}M:$ (d) sodium ion in the donor compartment inhibited the drug transport possibly due to decreasing the electric transference number of the drug; (e) delivery of ISP and PS increased as the pH of the donor solution increased over the pH range 2-7 suggesting permselective nature of the epidermis, and inhibition of the transference number of the drugs by hydronium ion; (f) some organic anions such as taurodeoxycholate, salicylate and benzoate which form lipophilic ion-pair complexes with ISP inhibited the delivery of ISP. The degree of inhibition by the organic anions was linearly proportional to the extraction coefficient $(K_e)$ of ISP from the partition system with each counteranion between phosphate buffer (pH 7.4) and n-octanol. For PS, however, taurodeoxycholate, but not salicylate and benzoate inhibited the iontophoretic delivery. It suggests that not only sodium ion and hydronium ion but also the counteranions which form lipophilic ion-pairs with quaternary ammonium drugs are not favorable components in formulating the donor solution of the drugs to achieve an effective iontophoretic delivery.

• Archives of Pharmacal Research
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• v.19 no.6
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• pp.435-440
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• 1996

The effect of benzalkonium chloride on skin permeability of partially modified antisense phosphorothioate oligonucleotides (PS-ODN), which are designed as scar formation inhibitor, was investigated using Franz Diffusion Cell. When the concentration ratio of PS-ODN-quarternary ammonium salt complex is more than 1:100, the apparent partition coefficient (APC) of each complex was increased in the following order; tetraphenyl phosphonium chloride (TPP) < cetyltrimethyl ammonium bromide(CTAB) < benzalkonium chloride (BZ). The permeability of PS-ODN through the rat skin increased in the presence of BZ. The fluxs of PS-ODN with BZ were increased by addition of Pluronic F 68 or Triton X-100 to phosphate buffered saline (PBS), respectively. When the mole ratio of PS-ODN to BZ is 1:10, the fluxs penetrated of PS-ODN with BZ was greatest. The increase of the permeability in the presence of BZ might be due to the formation of lipophilic ion-pair complex between PS-ODN and BZ. By regulation of mole ratio of PS-ODN to BZ, the development of topical dosage forms using PS-ODN as scar formation inhibitor will be possible with minimal systemic exposure.

• Analytical Science and Technology
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• v.6 no.3
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• pp.289-296
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• 1993

The formation of Mo(VI)-alizarin red S chelate ion and its extraction into an organic solvent by ion-pairing were studied for the separative determination of trace Mo(VI) in natural water samples. Natural water 100mL was sampled in 250mL separatory funnel. After Mo(VI)-ARS chelate ion was formed by adding 0.01M alizarin red S solution 0.5mL to the water sample of pH 4.0, 0.2% aliquat-336 chloroform solution 10mL was added and the solution was vigorously shaked for about 30 seconds to from the ion-pair between Mo(VI)-ARS and aliquat-336, completely. The solution was stood for about 90 minutes. And the organic phase was taken for the absorbance measurement of the ion-pair at 520 nm. The content of Mo(VI) in sample was obtained from the standard calibration curve. Several extraction conditions such as pH, adding amounts of alizarin red S and aliquat-336, and shaking and standing times were optimized. This procedure was applied to the analysis of river and tap waters. It could be confirmed from the recoveries of over 99% in samples spiked with a given amount of Mo(VI) that this method was quantitiative in the determination of trace Mo(VI) in a natural water.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.333-333
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• 2011

We studied the H/D exchange kinetics of pure and acid dopped water-ice film by using the techniques of reactive ions scattering (RIS) and low energy sputtering (LES) with low kinetic energy cesium ion beam (<35 eV). From RIS, neutral water isotopomers were detected in the form of cesium-molecule ion clusters, $CsX^+$ (X= $H_2O$, HDO, $D_2O$). Ionic species, like $H_3O^+$, $DH_2O^+$, $D_2HO^+$, $D_3O^+$, adsorbed on the surface were ejected via LES process. Those techniques allowed us to trace the isotopomeric populations of water-ice film. To show the catalytic effect of excess proton in the H/D exchange reaction, our study was conducted with two types of water-ice films. In film 1, about 0.5 BL of $H_2O$ was adsorbed on HCl (0.1 ML) dopped $D_2O$ (8 BL) film. In film 2, similar amount of $H_2O$ used in film 1 was adsorbed on pure $D_2O$ film. Kinetic data were obtained from each film type for 90-110 K (film 1) and 110-130 K (film 2) and fitted with numerically integrated lines. Through the Arrhenius plot of kinetic coefficient deduced from fitting of the H/D exchange reaction, the activation energy of film 1 and 2 were estimated to be $10{\pm}3kJmol^{-1}$ and $17{\pm}4kJmol^{-1}$. This activation barrier difference could be understood from detailed pictures of H/D exchange. In film 2, both the formation of ion pair, $H_3O^+$ and OH. and proton transfer were needed for the H/D exchange. However, in film 1, only proton transfer was necessary but ion pair formation was not, so this might reduce the activation energy.

• Archives of Pharmacal Research
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• v.9 no.2
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• pp.111-114
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• 1986

Bretylium tosylate is a quaternary ammonium compound used for the treatment of ventricular fibrilation in humans. It is advantageous to other cationic compound in the study of biliary excretion in that negligible amount is bound to plasma protein and metabolite is not likely is to be formed. Some researchers reported that the formation of ion-pair complex caused to increase the lipothilicity of cationic compound. The partition of bretylium between water and organic phase was increased with the addition of sodium taurodeoxycholate. Also sensitive gas chromatographical assay procedure using flame ionization detector was studied. This procedure can detect as low as 0.1 mg/ml using 0.1 ml biological sample, but contamination by previous injection is the major problem of this method.

• Analytical Science and Technology
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• v.6 no.3
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• pp.329-334
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• 1993

The formation of Mo(VI)-alizarin red S chelate ion its extraction into an organic solvent by ion-pairing for the separarive determination of trace Mo(VI) in natural water was applied in seawater samples. Removed Fe(III) and Zn(II), and Cu(II) by precipitating with anthranilic acid at pH 4.0 and 2.0, seawater 100mL was sampled in 250mL separatory funnel. After Mo(VI)-ARS chelate ion was formed by adding 0.01M alizarin red S solution 1.0mL to the water sample of pH 4.6, 0.6% aliquat-336 chloroform solution 10mL was added and the solution was vigorously shaked for about 30 seconds to form the ion-pair between Mo(VI)-ARS and aliquat-336 perfectly. The solution was stood for about 30 minutes. And the organic phase was taken for the absorbance measurement of the ion-pair at 520nm. The content of Mo(VI) was obtained from the standard calibration curve. Several extraction conditions such as pH, adding amounts of alizarin red S and aliquat-336, and shaking and standing times were optimized and the interferences and release of concomitant ions was also studied. This procedure was applied to the analysis of Eastern and Yellow seawaters. It could be confirmed from the recoveries of over 85% in samples spiked with a given amount of Mo(VI) that this method was also quantitative in the determination of trace Mo(VI) in a seawater.