• Bulletin of the Korean Chemical Society
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• v.16 no.2
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• pp.153-157
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• 1995

Calix[6]arenes are selectively dialkylated at the lower rim and further functionalized by the aminomethylation and Claisen Rearrangement reactions. Dialkylation was conducted by the reaction of calix[6]arene and alkyl halides such as benzyl bromide, allyl bromide, ethyl bromoacetate, propyl bromide, and methyl iodide under the carefully controlled reaction conditions. Aminomethylation was carried out with the treatment of disubstituted calix[6]arene and secondary amine in the presence of formaldehyde. Claisen rearrangement reaction of the O-diallylcalix[6]arene produced the p-diallylcalix[6]arene.

• Journal of the Korean Chemical Society
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• v.37 no.9
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• pp.793-799
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• 1993

Ion-pair model was predominated over ion-interaction model in the retention mechanism of analytes when tetramethylammonium bromide (TMAB) was used as a counter-ion in the investigation of aromatic sulfonic acids on the reversed-phase liquid chromatography by $C_{18}$ column as a stationary phase. The capacity factors of analytes were influenced by the type and concentration of counter-ions, concentrations of methanol and co-anion, types and position of functional group, and the pH mobile phase. Components of analyte mixture could be separated under the optimum conditions by this method.

• Polymer(Korea)
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• v.27 no.4
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• pp.392-395
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• 2003

Phosrhonium salt exchanged montmorillonites were prepared from a reaction between alkyl triphenyl phosponium bromide and Na$^{＋}$-montmorillonite. Epoxy-clay nanocomposites were also prepared by using cycloaliphtic epoxy, methyl tetrahydrophthalic anhydride as a hardener, and triphenyl butyl phosphonium bromide as an accelerator. TEM and XRD results suggested that clay minerals in the epoxy-montmorillonites composite were intercalated. Mechanical properties such as tensile modulus and strength were measured and the effect of nanocomposite formation was also discussed.

• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.2
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• pp.145-148
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• 2008

Cationic surfactant can be used as cosmetics and chemical dispersants. The variation of critical micelle concentration (CMC) with temperature over the range $40^{\circ}C$ to $60^{\circ}C$ for N-octadecyl pyridinium bromide was measured by drop methods. Thermodynamic quantities such as free energy, enthalpy, entropy and heat capacity for micellization of N-octadecyl pyridinium bromide in water were calculated by fourth-degree polynominal equation In the result, free energy change was decreased generally by the increment of temperature.

• Bulletin of the Korean Chemical Society
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• v.20 no.4
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• pp.451-455
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• 1999

The polymerization of 2-ethynylpyridine by alkyl bromide carrying carbazole moiety, 6-(N-carbazolyl)hexyl bromide, relatively proceed well to give the corresponding poly[6'-(N-carbazolyl)hexyl-2-ethynylpyridinium bromide) in high yields under DMF reflux conditions without any initiator or catalyst. This polymerization was influenced upon the initial monomer concentration. The polymer yields and inherent viscosities of the resulting polymers were in the range of 34-85% and 0.11-0.21 dL/g, respectively. Instrumental analyses using NMR, IR, and UV-visible spectroscopies and elemental analysis indicated that the resulting polymer has a conjugated polymer backbone system carrying pyridine and n-hexyl carbazole moiety. The polymers were mostly brown powders and completely soluble in DMF, DMSO, nitrobenzene, and formic acid. The photoluminescence spectrum of the dilute polymer solution with the excitation at 383 nm exhibited two sharp peaks at 495 and 540 nm.

• Bulletin of the Korean Chemical Society
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• v.27 no.7
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• pp.1079-1082
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• 2006

• Bulletin of the Korean Chemical Society
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• v.31 no.7
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• pp.1829-1830
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• 2010

• Bulletin of the Korean Chemical Society
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• v.31 no.7
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• pp.1831-1832
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• 2010

• The Journal of the Korean dental association
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• v.10 no.10
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• pp.659-664
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• 1972

• Bulletin of the Korean Chemical Society
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• v.19 no.1
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• pp.22-23
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• 1998