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${\alpha}$-(n-Butyl)-N-Phenylnitrone유도체의 가수분해 반응메카니즘과 반응속도론적 연구
이석우,곽천근,이광일,이기창,Lee Seok-Woo,Chun-Geun Kwak,Kwang-Il Lee,Lee Ki-Chang 대한화학회 1992 대한화학회지 Vol.36 No.4
${\alpha}$-(n-butyl)-N-phenylnitrone 유도체들의 가수분해 반응속도상수를 $25^{\circ}C$의 수용액에서 자외선 분광광도법으로 측정하여 넓은 pH 범위에서 잘 맞는 반응속도식을 구하였다. 반응속도식, 가수분해 생성물, 일반염기(general base) 및 치환기 효과 등의 결과로부터 가수분해 반응메카니즘을 제안하였다. 즉, pH 4.5이하에서의 가수분해는 양성자가 첨가된 nitrone의 ${\alpha}$-탄소에 물분자의 공격에 의해 진행되며, pH 10.0 이상에서는 ${\alpha}$-탄소에 히드록시 이온의 직접 첨가에 의하여 가수분해가 진행된다. pH 4.5∼10.0에서는 nitrone에 물분자가 첨가되는 것이 속도결정단계임을 알았다. The rate constants of hydrolysis of ${\alpha}$-(n-butyl)-N-phenylnitrone and its derivatives have been determined by UV spectrophotometry at 25$^{\circ}C$ and a rate equation which can be applied over a wide pH range was obtained. On the basis of rate equations derived and judging from the hydrolysis products obtained and from general base and substituent effects, plausible mechanisms of hydrolysis in various pH range have been proposed. Below pH 4.5, the hydrolysis was initiated by the protonation and followed by the addition of water to ${\alpha}$-carbon. Above pH 10.0, the hydrolysis was proceeded by the addition of hydroxide ion to ${\alpha}$-carbon. In the range of pH4.5∼10.0, the addition of water to nitrone is rate controlling step.
α-Phenyl-N-iso-Propylnitrone 유도체의 가수분해 반응 메카니즘과 반응 속도론적 연구
곽천근,장병만,이석우,이기창 ( Chun Geun Kwak,Byung Man Jang,Seok Woo Lee,Ki Chang Lee ) 한국유화학회 1994 한국응용과학기술학회지 Vol.11 No.1
The rate constants of hydrolysis of α-phenly-N-iso-propylnitrone and its derivatives have been determined by UV spectrophotmetry at 25℃ and a rate equation which can be applied over a wide pH range was obtained. On the basis of rate equations derived and judging from the hydrolysis products obtained and general base and substituent effect, plausible mechanism of hydrolysis in various pH range have been proposed. Below pH 4.5, the hydrolysis was initiated by the protonation and followed by the addition of water to α-carbon. Above pH 10.0, the hydrolysis was proceeded by the addition of hydroxide ion to α=carbon. In the range of 4.5~10.0, the addition of water to nitrone was rate controlling step.
1,1,1-TCE , CFC-113 대체세정제를 이용한 스크린인쇄 세정연구
이기창,윤철훈,황성규,오세영,이석우,류정욱 ( Ki Chang Lee,Cheol Hun Yoon,Sung Kwy Hwang,Se young Oh,Seok Woo Lee,Jung Wok Ryu ) 한국유화학회 1997 한국응용과학기술학회지 Vol.14 No.2
The field of printing use to pressurization ink using screen gassamer that is called screen printing. Existing cleaning solvent using screen printing are he organic solvents including aromatic compounds carried with poisonous and stench. Besides, cleaning method of current screen printing are for the most part mixed cleaning method of dipping and polish. Using 1,1,1-TEC, CFC-113 alternative system cleaning solvent be substituted for existing cleaning solvent against screen printing ink measured the cleaning efficiency according to gravimetric analysis method and property change of gassamer according to Image Analyzer. Also, Cleaning process system carry with excellent cleaning efficiency studied which was proposed new cleaning process including ultrasonic and vibration cleaning process be substituted for existing mixed cleaning method of dipping and polish.
벤조산 유도체 Ⅱ . Furyl Chalcone 유도체의 가수분해 반응메카니즘과 그 반응속도론적 연구
이기창,황용현,류완호,양천회,이석우 ( Ki Chang Lee,Yong Hyun Hwang,Wan Ho Ryu,Cheon Hoi Yang,Seok Woo Lee ) 한국유화학회 1993 한국응용과학기술학회지 Vol.10 No.1
The hydrolysis kinetics of 2-furyl chalcone derivatives [Ⅰ]~[Ⅴ] was investigated by ultraviolet spectrophotometery in 30% dioxane-H_2O at 25℃ and the structure of these compounds were ascertained by means of ultraviolet, infrared and NMR spectra. The rate equations which were applied over a wide pH range(pH 1.0~12.0) were obtained. The substituent effects on 2-furyl chalcone derivatives [Ⅰ]~[Ⅴ] were studied, and the hydrolysis were facilitated by the electron attrecting groups. On the basis of the rate equation, substituent effect, general base effect and final product, the plausible hydrolysis mechanism was proposed: Below pH 4.0, it was only proportional to concentration of hydronium ion, at pH 4.0~9.0, neutral H_2O molecule competitively attacked on the double bond. By contrast, above pH 9.0, it was proportional to concentration of hydroxide ion.
2,3-Disubstituted-4-Oxo-1,2,3,4-Tetrahydroquinazoline 유도체의 합성
이기창,류정욱,이석우,서상균 明知大學校 産業技術硏究所 1987 産業技術硏究所論文集 Vol.6 No.2
2, 3-Disubstituted-4-oxo-1, 2, 3, 4-tetrahydroquinazolines were synthesized by using the isatoic anhydrides and N-substituted-2-aminobenzamides as starting materials. Intermediates were formed by the reaction of isatoic anhydride with primary amines at various conditions. Final products, 2, 3-Disubstituted-4-oxo-1, 2, 3, 4-tetrahydroquinazolines were synthesized by the fusion of pyridine-3-aldehyde with intermediates for 5hrs at various conditions. By using IR, NMR, MS and elementary analysis, each product was identified and yield of 2, 2-disubstituted-4-oxo-1,2,3,4-tetrahydroquinazolines was nearly 80-90%.
이기창,류정욱,이석우,윤철훈,정덕채 한국유화학회 1991 한국응용과학기술학회지 Vol.8 No.2
The kinetics of hydrolysis of cinnamenylisophorone derivatives (p-H, p-Br, p-CI, p-OCH_3) was investigated using ultraviolet spectrophotometry in 20%(v/v) dioxane-H_2O at 25℃. A rate equation which can be applied over wide pH range(pH 1.0~13.0) was obtained. In order to investigate the substituent effects on cinnamenylisophorone derivatives. Hammett constant was plotted. As the result, the rate of hydrolysis of cinnamenylisophorone derivatives was facilitated by electron donating group. Final products of the hydrolysis were benzaldehyde and isophorone. From the measurement of reaction rate constant according to pH changes, substituent effect, and final products, it was found that the hydrolysis of cinnamenylisophorone derivatives was initiated by the neutral H_2O molecule which does not dissociated at below pH 9.0, and in the hydroxide ion above pH 11.0. On the basis of this kinetic study, the reaction mechanism of the hydrolysis of cinnamenylisophorone derivatives was proposed.