• Journal of the Korean Chemical Society
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• v.52 no.5
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• pp.593-596
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• 2008

• Journal of the Korean Chemical Society
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• v.55 no.3
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• pp.430-435
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• 2011

Coal fly ash of thermal power plants converted into mesoporous materials MCM-41. The synthesized material was characterized by XRD, FT-IR, SEM, and EDS techniques. The catalytic activity of prepared material was studied for the synthesis of 5-arylindene malononitriles via Knoevenagel condensation of aromatic aldehydes and malonontrile is described. The features of present method are easy handling, stability, reusability, and eco-friendliness of catalyst, high yields, short reaction time, simple experimental and work up procedure.

• Korean Chemical Engineering Research
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• v.44 no.4
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• pp.417-423
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• 2006

A series of amine functionalized MCM-41 catalysts were prepared by aminopropyltrimethoxysilane grafting and their catalytic performance in Knoevenagel reaction of selected substrates was investigated. Water resistant and catalytically active amine grafted MCM-41 was prepared by post-synthetic silylation using methyltrimethoxysilane ; hydrogen bonding of the water molecules formed during the condensation reaction to the active N group was suppressed, which led to high TON of the reaction. Amine functionalized MCM-41 prepared by coating method produced high conversion, but the TON of the catalyst was much lower than that of the amine grafted MCM-41; pore volume of the functionalized MCM-41 decreased substantially and large portion of the immobilized amine is believed to be hydrogen bonded to each other, which can result in decrease in the basicity of the N group. A secondary amine group was prepared by room temperature condensation between aminopropylsilane and chloropropylsilane, and the MCM-41 grafted with the secondary amine group demonstrated the highest catalytic activity among the catalysts prepared.

• Journal of the Korean Chemical Society
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• v.51 no.4
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• pp.346-351
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• 2007

Efficient stereoselective synthesis of α,β-Unsaturated acids, α-Cyanoacrylonitriles and α-Cyanoacrylates has been carried out in the presence of NaHSO4·SiO2 under solvent?free conditions with an E-geometry.

• Applied Chemistry for Engineering
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• v.17 no.6
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• pp.609-613
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• 2006

4-(Dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM) derivatives were synthesized by Knoevenagel condensation. They are red-emitting materials for OLED (Organic Light-Emitting Diode) composed of electron donor of aminostyryl groups and electron acceptor of two cyano(nitrile)groups in a conjugated structure. The structural properties of reaction products were analyzed by FT-IR and $^1H-NMR$ spectroscopy. The thermal stabilities and reactivities were measured by melting points and yields. The UV-visible and PL properties can be determined by exitation and emission spectra, respectively.

• Applied Chemistry for Engineering
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• v.20 no.1
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• pp.40-45
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• 2009

N-Alkylcarbazole-3-vinylene-2-methyl-4-dicyanomethylene-4H-pyran derivatives were synthesized by dehydration, $S_N2$, Vilsmeier, and Knoevenagel condensation. They are red-emitting materials for organic light emitting device (OLED) composed of electron donor of N-alkylcabazole-3-vinylene groups and electron acceptor of 2-methyl-4-dicyanomethylene-4H-pyran groups by a conjugated structure. The structural properties of reaction products were analyzed FT-IR and $^1H-NMR$ spectroscopy. The thermal stabilities and reactivities were measured by melting points and yields. The UV-visibles and PL properties can be determined by exitation spectra and emission spectra, respectively.

• Applied Chemistry for Engineering
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• v.18 no.6
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• pp.587-591
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• 2007

6-(10-Alkylphenothiazine-3-vinylene)-2-methyl-4-dicyanomethylene-4H-pyran derivatives were synthesized by Knoevenagel condensation. They are red-emitting materials for organic light emitting device (OLED) which composed of electron donor of 6-(10-Alkylphenothiazine-3-vinylene) groups and electron acceptor of -2-methyl-4-dicyanomethylene-4H-pyran groups by a conjugated structure. The structural properties of reaction products were analyzed FT-IR and $^1H-NMR$ spectroscopy. The thermal stabilities and reactivities were measured by melting points and yields. The UV-visibles and PL properties can be determined by exitation spectra and emission spectra, respectively.

• Polymer(Korea)
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• v.32 no.1
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• pp.56-62
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• 2008

Three types of network polyesters have been newly synthesized by a two-step condensation reaction by the various combination of several diols and diacids. When these polymer films were thermally treated at $240^{\circ}C$, they exhibited absorptions in a visible range despite the forbidden transition of carbonyl group. When excited at wavelengths above 330 nm, the polymers showed fluorescences in a wide visible range from blue to near yellow. These fluorescence phenomena are due to the formation of certain conjugated structures by the Knoevenagel type self-condensation under the high-temperature thermal treatment. These polymers showed significant difference in the thermal properties as a function of the degrees of chemical crosslinking. They also underwent photodegradation. Highly resolved, fluorescent image patterns were successfully obtained by the photodegradation of malonate group under a strong UV-light irradiation.

• Applied Chemistry for Engineering
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• v.22 no.4
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• pp.348-352
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• 2011

In this research, we have synthesized new pendant-type polyurethane polymers by introducing various chromophores with stilbene derivatives in the side-chain of the polymer backbone. The Stilbene monomers, N,N-bis(2-hydroxyethyl) amino-4'-cyanostilbene, N,N-bis(2-hydroxyethyl)amino-4'-methoxy stilbene, N,N-bis(2-hydroxyethyl)amino-4'-acetylstilbene, and N,N-bis(2-hydroxyethyl) amino stilbene, were synthesized by Wittig reaction. Another stilbene monomer, N,N-bis(2-hydroxyethyl)amino-4'-nitrostilbene, was synthesized by Knoevenagel condensation. By the measurement of UV-Vis absorption and Photoluminescence (PL) spectrum, we found that introduction of the electron-withdrawing group as a substituent shifts both UV-Vis and PL spectra to longer wavelength, and the introduction of the electron-donating group results in blue-shift of the spectrum. In case of polymer with $NO_2$ group as a substituent, PL is quenched.

• Polymer(Korea)
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• v.34 no.5
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• pp.424-429
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• 2010

The hybrid composites of aliphatic polyester-silica were prepared via a sol-gel reaction and their potential application using as a buffer coating layer in the thermoelectric device were investigated. When aliphatic polyesters were thermally treated at a high temperature of $240^{\circ}C$, the polymer showed an increases in thermal degradation temperature by $30{\sim}90^{\circ}C$ according to the thermal treatment time. The polyester-silica composites showed an increases in thermal degradation temperature by $30{\sim}50^{\circ}C$ according to the content of the added silica. Polyester-silica composite showed neither discoloration nor change in optical properties because Knoevenagel condensation reaction was hindered by silica structure. The thermal conductivity of the composites increased linearly according to the content of added silica.