http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
${\alpha}$-(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.
α-phenyl-N-iso-propylnitrone유도체에 대한 1-propanethiol의 친핵성 첨가반응에 관한 연구
이광일(Lee Kwang Il)(李光一),곽천근(Kwak Chun Geun)(郭仟根),장병만(Jang Byung Man)(張炳萬),김영주(Kim Young Ju)(金榮珠),지윤섭(Ji Yun Seup)(池允燮),이기창(Lee Ki Chang)(李基昌) 한국유화학회 1995 한국응용과학기술학회지 Vol.12 No.2
The rate constant of the nucleophilic addition of 1-propanethiol to α-phenyl-N-iso-propylnitrone derivatives were determined at various pH and a rate equation which can be applied over wide pH range is obtained. Final product of the addition reaction was α-thiopropyl-p-phenylbenzylideneamine. Base on the rate equation, general base effect, substituent effect and final product, plausible mechanism of addition reaction have been proposed. Below pH 3.0, the reaction was initiated by the addition of 1-propanthiol, and in the range of pH 3.0-10.0, proceeded by the competitive addition of 1-propanethiol and propanethiolate. Above the pH 10.0, the reaction proceeded through the addition of propanethiolate.
수용성 Chitosam 유도체를 이용한 중금속 이온 흡착에 관한 연구
이광일,곽천근,김영주,장병만,김상호,이기창 ( Kwang Il Lee,Chun Geun Kwak,Young Ju Kim,Buyng Man Jang,Sang ho Kim,Ki Chang Lee ) 한국유화학회 1996 한국응용과학기술학회지 Vol.13 No.2
Chitosan itself has been prepared using chitin, one of the most abundant compounds in nature, as a starting material. We have synthesized the water-soluble chitosan derivative, N-dithiocarboxy chitosan sodium salt, through the reaction of water-soluble chiotsan with carbon disulfide in the presence of alkali metal hydroxide. To elucidate this natural polymer capacity of adsorbing heavy metal ions, we have performed adsorption experiments using the water-soluble chitosan derivative various average molecular weight and of different percent contents of sulfur. The effect of pH, adsorption time and temperature on adsorption efficiency was also studied, The adsorbent derived from water-soluble chitosan of average molecular weight ranging 9,000~120,000 was shown to have the highest capacity of adsorbing heavy metal ions. On the whole, adsorbing efficiency was increased as the reaction time goes longer and also increased as the reaction temperature goes higer in temperature range of 15℃~45℃. The adsorption capacity at various pH, however, was appeared to vary depending on the heavy metal ions studied Judging from these finding, water-soluble N-dithiocarboxy chitosan sodium salt, a derivative of a biodegradable nature polymer, is believed to be a potential adsorbent for heavy metal ions since it not only is shown to lower the concentration of heavy metal ions to below the drainage quality standard, but also it would not cause acidification and hardening of soil which is one of the detrimental effects of synthetic macromolecular adsorbents present.
Chitosan 및 Chitosan 유도체를 이용한 중금속 이온 흡착에 관한 연구
이광일,곽천근,장병만,김영주,박태홍,노승일,이기창 ( Kwang Ill Lee,Chun Geun Kwak,Young Ju Kim,Tae Hong Park,Seung IlI Roh,Ki Chang Lee ) 한국유화학회 1996 한국응용과학기술학회지 Vol.13 No.3
We have synthesized the water-insoluble chitosan derivative, N-dithiocarboxy chitosan sodium salt, through the reaction of chitosan with carbon disulfide in the presence of alkali metal hydroxide, Chitosan itselt has been prepared using chitin, one of the most abundant compounds in nature, as a starting material. To elucidate this natural polymer the capacity of adsorbing heavy metal ions, we have performed adsorption experiments using chitosan derivatives of various average molecular weights with different contents of sulfur. The effect of pH, adsorption time and temperature on adsorption efficiency was also studied. The adsorbent derived from chitosan of average molecular weight ranging 5,700~20,000 was shown to have the highest capacity of adsorbing heavy metal ions. Adsorbing efficiency was increased as the reaction time was increased and as the reaction temperature range of 25~45℃. The adsorption capacity at various pH, however, appeared to vary depending on the heavy metal ions studied,
Dihydro-1,4-oxathiin 유도체의 가수분해 Mechanism과 반응속도론적 연구
이광일,곽천근,장병만,김영주,한호규,남기달,이기창,Lee, Kwang Il,Kwak, Chun Geun,Jang, Byung Man,Kim, Young Ju,Hahn, Hoh Gyu,Nam, Kee Dal,Lee, Ki Chang 대한화학회 1996 대한화학회지 Vol.40 No.2
Dihydro-1, 4-oxathiin 유도체의 가수분해 반응속도를 25.deg.C의 수용액에서 자외선 분광기를 사용하여 측정하고 넓은 pH범위에서 적용될 수 있는 반응속도식을 유도하였다. 가수분해 반응속에에 미치는 치환기 효과를 검토하기 위하여 Hammett plot한 결과 전자 끄는기에 의하여 반응속도가 촉진됨을 확인할 수 있었다. 가수분해 최종 생성물은 2-(2-hydroxyethylthio)acetoacetanilide enol형이었다. 가수분해 반응속도상수 측정실험과 반응식 유도과장, 일반염기 효과, 치환기 효과 및 최종 생성물의 결과로부터 dihydro-1, 4-oxathiin 유도체의 기수분해 반응 메카니즘을 제안하였다. pH3.5이하에서는 양서자가 첨가된 dihydro-1, 4-oxathiin의 2번 탄소에 물분자의 공격에 의해 진행되며, pH3.5 이상에서는 2번 탄소에 히드록시이온의 첨가에 의하여 진행됨을 알 수 있었다. pH4.0-9.0사이에서는 dihydro-1, 4-oxathiin에 중성의 물분자가 첨가되는 것이 속도결정단계임을 알았다. The kinetics of the hydrolysis of dihydro-1, 4-oxathiin derivatives were investigated by ultraviolet spectrophotometry in H2O at $25^{\circ}C.$ A rate equation which can be applied over a wide pH range was obtained. The substituent effects on the hydrolysis of dihydro-1, 4-oxathiin derivatives were studied and the rate of hydrolysis was shown to be accelerated by electron accepting groups. Final product of the hydrolysis was 2-(2-hydroxyethylthio)acetoacet-anilide enol form. On the basis of rate equations derived and judging from hydrolysis products obtained and from general base effect and substituent effects, plausible mechanism of the hydrolysis in various pH range have been proposed. Below pH 3.5, the hydrolysis was initiated by the protonation and followed by the addition of water to 2-carbon. Above pH 10.0, the hydrolysis was proceeded by the addition of hydroxide to 2-carbon. In the range of pH 4.0∼10.0, the addition of water to dihydro-1,4-oxathiin is rate controlling step.