Journal of the Korean Chemical Society (대한화학회지)

Korean Chemical Society (대한화학회)
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Kinetics and Mechanism of the Hydrolysis of ${\alpha}$-(n-Butyl)-N-Phenylnitrone

${\alpha}$-(n-Butyl)-N-Phenylnitrone유도체의 가수분해 반응메카니즘과 반응속도론적 연구

  • Lee Seok-Woo (Department of Chemistry, Kyonggi University) ;
  • Chun-Geun Kwak (Department of Chemistry, Kyonggi University) ;
  • Kwang-Il Lee (Department of Chemistry, Kyonggi University) ;
  • Lee Ki-Chang (Department of Chemical Engineering, Myongji University)
  • 이석우 (경기대학교 이과대학 화학과) ;
  • 곽천근 (경기대학교 이과대학 화학과) ;
  • 이광일 (경기대학교 이과대학 화학과) ;
  • 이기창 (명지대학교 화학공학과)
  • Published : 1992.08.20
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Abstract

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.

${\alpha}$-(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.

Keywords

References

  1. J. Chem. Soc. Perkin Trans. I v.15 M. Masui;K. Suda;M. Yamauchi
  2. J. Chem. Soc. E. Boyland;R. Nery
  3. Tetrahedron Lett. v.31 N. G. Clark;E. Cawkii
  4. J. Chem. Soc. Perkin Trans. II H. Ohmori;C. Ueda
  5. J. Chem. Soc. Perkin Trans. II Y. Ogata;A. Kawaski
  6. Chem. Comm. M. Masui;M. Yamauchi
  7. Chem. Rev. v.64 J. Hammer;A. Macaluso
  8. J. Amer. Chem. Soc. v.84 E. H. Cordes;W. P. Jencks
  9. Bull. Kor. Chem. Soc. v.12 T. R. Kim;K. I. Lee
  10. J. Kor. Chem. Soc. v.35 T. R. Kim;S. Y. Pyun;M. S. Han;K. I. Lee
  11. Bull. Kor. Chem. Soc. v.12 T. R. Kim;K. I. Lee;S. Y. Pyun
  12. Organic Syntheses (Coll) v.1 O. Kamm
  13. J. Am. Chem. Soc. v.78 O. H. Wheeler;P. H. Gore