• Title/Summary/Keyword: phenoxy

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H-Shaped Dimesogenic Compounds; Synthesis and Thermotropic Properties of α, ω-Bis[2,5-bis(4-cyanophenoxycarbonyl)phenoxy]alkanes (H-자형 이메소제닉 화합물; α,ω-Bis(2,5-bis(4-cyanophenoxy carbonyl)phenoxy)alkanes의 합성과 열방성 성질)

Determination of Reactivities by MO (ⅩⅦ). Theoretical Studies on Phenolic Antioxidants (MO 이론에 의한 반응성의 결정 (제17보). 페놀계 산화방지제에 관한 이론적 연구)

  • Ikchoon Lee;Young Gu Cheun
    • Journal of the Korean Chemical Society
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    • v.24 no.5
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    • pp.337-341
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    • 1980

  • Radical formation reaction of phenolic antioxidants were examined MO theoretically. Results show that substitution of electron-donating alkyl groups in phenol increases the rate of phenoxy radical formation when attacked by an electrophilic radical by stabilization of cationic transition state.

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Synthesis of New 5-Benzyl-4-cyanomethyl-2-methylpyrimidine Derivatives (새로운 5-Benzyl-4-cyanomethyl-2-methylpyrimidine 유도체들의 합성)

  • Kim, Jung Hwan;Han, Mun Su
    • Journal of the Korean Chemical Society
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    • v.40 no.4
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    • pp.249-253
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    • 1996

  • The synthesis of new 5-benzyl-4-cyanomethyl-2-methylpyrimidine derivatives (5) containing chloro, methoxy, ethoxy, phenoxy and anilino groups at 6-position on the pyrimidine ring were prepared from 5-benzyl-4-chloro-2-methylpyrimidine derivatives (3) and tert-butylcyanoacetate. The derivatives of 5-benzyl-4-chloro-2-methylpyrimidine (3) containing chloro, methoxy, ethoxy, isopropoxy, phenoxy and anilino groups at 6-position on the pyrimidine ring were prepared from 5-benzyl-4,6-dichloro-2-methylpyrimidine (2).

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Preconcentration and Detection of Herbicides in Water by Using the On-line SPE-HPLC System and Photochemical Reaction

  • 이승호;이성광;박영훈;김현주;이대운
    • Bulletin of the Korean Chemical Society
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    • v.20 no.10
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    • pp.1165-1171
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    • 1999

  • The analysis of trace herbicides using the on-line SPE-HPLC system and a photochemical reaction was studied. 18 compounds of herbicides including eight triazines, six phenoxy acids and esters, and four other herbicides were examined. The on-line SPE-HPLC system developed for selection of eluting solvent improved chromatographic efficiency. The recoveries of herbicides were higher than 77%. With 100 mL tap water samples, the detection limits for all analytes were in the 0.1-2.3×10-10 M range. Detection was done by a UV or fluorescence spectrometer after photochemical reaction at the end of the column with 2W or 450W mercury lamp. Without a photochemical reaction, all compounds responded to 230 nm UV detector, but phenoxy acids and esters were weakly detected. However, with a photochemical reaction, these compounds were selectively detected at 320 nm wavelength of UV absorption and 400 nm emission of the fluorescence detectors. This method can be used for the analysis of environmental water containing herbicides at trace levels.

  • https://doi.org/10.5012/bkcs.1999.20.10.1165 인용 PDF

Synthesis and Properties of Thermotropic Compounds with Two Terminal Mesogenic Units and a Central Spacer Ⅲ. Homologous Series of $\alpha,\omega$-Bis[4-(p-nitrobenzoyloxy)phenoxy]alkanes

  • Jin, Jung-Il;Kang, Joo-Sam;Jo, Byung-Wook;Lenz, Robert W.
    • Bulletin of the Korean Chemical Society
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    • v.4 no.4
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    • pp.176-180
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    • 1983

  • A series of new liquid crystalline compounds having two identical mesogenic terminal units, the 4-(p-nitrobenzoyloxy)phenoxy group, attached to both ends of a central polymethylene spacer of various lengths was prepared. The mesomorphic properties of the compounds were investigated by differential scanning calorimetry (DSC) and by polarizing microscopy. Almost all of the compounds formed monotropic nematic mesophases. The trimethylene spacer compound was found to be non-liquid crystalline, while the one with the hexamethylene central spacer was enantiotropic. A thermodynamic analysis was performed for the phase transitions of the compounds and the results are discussed in relation to their liquid crystal properties.

  • https://doi.org/10.5012/bkcs.1983.4.4.176 인용 PDF