• Journal of the Korean Applied Science and Technology
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• v.7 no.2
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• pp.11-18
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• 1990

N-alkyl carboxy pyridinium chlorides such as N-lauryl carboxy-pyridinium chloride, N-myristyl carboxy pyridinium chloride, N-cetyl carboxy pyridinium chloride and N-stearyl carboxy pyridinium chloride were synthesized by the reaction of nicotinic acid and isonicotinic acid with long chain alkyl chlorides, and N-alkyl pyrinium carboxylates such as N-lauryl pyridinium carboxylate, N-myristyl pyridinium carboxylate. N-cetyl pyridinium carboxylate and N-stearyl pyridinium carboxylate were prepared from N-alkyl carboxy pyridinium chlorides. These reaction products could be separated by both column chromatogrphy, and paper chromatography, and there dissociation constants of N-alkyl pyridinium carboxylates were found to pKa $1.0{\times}10^{13}{\sim}6,31{\times}10^{14}$.

• Journal of the Korean Chemical Society
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• v.19 no.6
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• pp.398-402
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• 1975

The light scattering studies of the aqueous solution of dodecyl pyridinium chloride (DPC) and tetradecyl pyridinium chloride (TPC) over the concentration range of 0~70 mM revealed that there exists a so-called 2nd critical micelle concentration (cmc) at about 43 mM and 8 mM respectively in addition to their 1st cmc at 17 mM and 3.5 mM. The 2nd cmc was greatly influenced by additives KCl, which lowered the 2nd cmc. The micelle molecular weight of DPC and TPC solutions at 1st cmc were 20800 and 15600 and the degree of ionization of their micelles at 1st cmc were 0.092 and 0.226 respectively.

• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.4
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• pp.51-54
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• 2007

Surfactants can be used as a cosmetics and chemical dispersants. The variation of critical micelle concentration(CMC) with temperature for hexadecyl pyridinium bromide over the range $40^{\circ}C$ to $60^{\circ}C$ has been measured by drop methods. Thermodynamic quantities for micellization of hexadecyl pyridinium bromide in water have been calculated by polynominal equation.

• Journal of the Korean Applied Science and Technology
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• v.6 no.2
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• pp.39-44
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• 1989

(N-docosyl pyridinium)-TCNQ(1:1) complex was synthesized by reacting N-docosyl pyridinium bromide and LiTCNQ. This complex was investigated and confirmed by elemental analysis. U.V, I.R spectra. A stability to the dispersion solvent, which is acetonitrile, dichloromethane, benzene, chloroform and acetonitrile-benzene (1:1, V/V) of (N-docosyl pyridinium)-TCNQ(1:1) complex was investigated by U. V spectrophotometer and was confirmed stabilized on acetonitrile, benzene and acetonitrile-benzene(1:1'V/V) for 7 hours. Using ultra pure water as subphase for L-B film deposition, the Y-type L-B film of (N-docosyl pyridinium)-TCNQ(1:1) complex was farbricated. The electrical conductivities on a perpendicular direction of the L-B film were measured to be $5{\times}10^{-5}{\sim}5{\times}10^{-14}$S/cm according to the number of layer.

• Applied Chemistry for Engineering
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• v.16 no.1
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• pp.153-157
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• 2005

4-(Dimethylamino)pyridinium dichromate was synthesized by the reaction of 4-(dimethylamino)pyridine with chromium(VI)trioxide in $H_2O$, and characterized by IR, EA and ICP. The oxidation of benzyl alcohol using 4-(dimethylamino)pyridinium dichromate in various solvents showed that the reactivity increased with the increase of the dielectric constant, in the order: cyclohexen < chloroform < acetone < N,N-dimethylformamide. In the presence of hydrochloric acid(HCl), 4-(dimethylamino)pyridinium dichromate oxidized benzyl alcohol and its derivatives ($p-CH_3$, H, m-Br, $m-NO_2$) smoothly in N,N-dimethylformamide. Electron-donating substituents accelerated the reaction, whereas electron-withdrawing groups retarded the reaction. The Hammett reaction constant($\rho$) was -0.70 at 303K. The observed experimental data have been rationalized as follows: the proton transfer occurs after the prior formation of a chromate ester in the rate-determining step.

• Bulletin of the Korean Chemical Society
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• v.12 no.2
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• pp.163-169
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• 1991

The photochemical and photophysical properties of N-(2-haloarylmethyl)pyridinium, N-(arylmethyl)-2-halopyridinium, N-(2-haloarylmethyl)-2-halopyridinium salts and N-(2-halobenzyl)-isoquinolinium salt are studied. The pyridinium salts photocyclize to afford isoindolium salts, while the isoquinolium salts do not. In the photocyclization of N-(2-chlorobenzyl)-2-chloropyridinium salts, pyrido[2,1-a]-4-chloroisoindolium salt is formed by the cleavage of chlorine of pyridinium ring. This indicates that the excited moiety is not the phenyl ring, but the pyridinium ring. The triplet states of the pyridinium salts are believed to be largely involved in the photocyclization, since oxygen retards most of the reaction. Some assistance of a ${\pi}$-complex between the excited chlorine moiety of the salt and phenyl plane of the same molecule is required to explain the reactivity of the salts. N-(Benzyl)-2-chloropyridinium salt is two times more reactive than N-(2-chlorobenzyl)pyridinium salt. N-(Benzyl)-2-chloropyridinium salt can form ${\pi}-complex$ effectively because of the electron-rich phenyl group. The ${\pi}$-complex affords an intermediate, phenyl radical by cleaving the chlorine atom. The photocyclized product, isoindolium salt is obtained by losing the hydrogen atom from the phenyl radical. The reactive pyridinium salts 1a, 2a and 3a have a low fluorescence quantum yield (${\Phi}F$ < 0.01) and a higher triplet energy (ET > 68 kcal/mole) than the unreactive quinolinium salt. The unreactivity of isoquinolinium salt can be understood in relation to its high fluorescence quantum yield and its low triplet energy $(E_T = 61 kcal/mole).$.

• Journal of the Korean Chemical Society
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• v.40 no.2
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• pp.148-151
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• 1996

• Bulletin of the Korean Chemical Society
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• v.21 no.4
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• pp.375-376
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• 2000

• Bulletin of the Korean Chemical Society
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• v.20 no.11
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• pp.1373-1374
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• 1999

• Macromolecular Research
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• v.12 no.4
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• pp.407-412
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• 2004

A new hydroxyl group-containing conjugated ionic polymer, poly[2-ethynyl-N-(p-hydroxyphenylethyl)pyridinium bromide], was synthesized by the activated polymerization of 2-ethynylpyridine with p-(2-bromoethyl) phenol without any additional initiator or catalyst. The polymerization proceeded well to give a moderate yield (65%) of polymer at a reaction temparature of 90$^{\circ}C$. Another polymer, poly[2-ethynyl-N-(p-hydroxyphenylethyl)pyridinium tetraphenylborate], was readily prepared by the ion-exchange reaction of poly[2-ethynyl-N-(p-hydroxyphenylethyl)pyridinium bromide] with sodium tetraphenylborate. These polymers were completely soluble in organic solvents such as DMF, DMSO, and acetone, but insoluble in water and ether. Instrumental analyses, such as NMR, IR, and UV-Vis spectroscopies, indicated that the new materials have conjugated polymer backbone systems with the designed substituents and counter anions. X-Ray diffraction analyses of the polymers indicated that they were mostly amorphous.