Journal of the Korean Chemical Society (대한화학회지)

Korean Chemical Society (대한화학회)
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Nucleophilic Displacement at Sulfur Center (ⅩⅢ). Solvolysis of para-Substituted Benzenesulfonyl Chlorides in MeOH-MeCN Mixtures

황의 친핵성 치환반응 (제13보). 메탄올-아세토니트닐계에서의 파라치환 염화벤젠술포닐의 가용매 분해반응

  • Ikchoon Lee (Department of Chemistry, Inha University) ;
  • In Sun Koo (Department of Chemistry, Inha University)
  • 이익춘 (인하대학교 이과대학 화학과) ;
  • 구인선 (인하대학교 이과대학 화학과)
  • Published : 1981.02.28
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Abstract

Solvolysis of $p-CH_3, p-H, p-Cl and p-NO_2$-benzenesulfonyl chlorides have heen studied in MeOH-MeCN mixtures. A nonlinear Hammett plot with a ratio order of p-NO_2 > p-CH_3 > p-H > p-Cl was obtained; the reaction was thought to proceed by an S_N1-S_N2 borderline mechanism. In all cases the reactivity was a maximum at 90∼95%(v) methanol, whereas methanol monomer selectivity defined as fi = \frac{k1}{ki}i (k1; observed pseudo-first order rate constant: ki; hypothetical rate constant for MeOH solution having the same polymer structure as in the pure MeOH) was a maximum at 80% methanol with a decreasing order of fi as p-NO_2 > p-Cl > p-H > p-CH_3.$ This was interpreted as the decrease in tightness of transition state; the larger the fi, the tighter is the MeOH attached to the substrate, and hence the more susceptible the substrate becomes to the approaching monomer methanol.

$p-CH_3, p-H, p-Cl 및 p-NO_2 기로 치환된 염화벤젠술포닐의 가용매분해반응을 MeOH-MeCN혼합용매계에서 연구하였다. 반응속도는 p-NO_2 > p-CH_3 > p-H > p-Cl의 순위로서 비직선 Hammett관계를 나타내어 S_N1-S_N2경계반응메카니즘으로 반응함을 알았다. 반응성은 모든 경우 약 90∼95% 메탄올용액에서 최대였으나, fi = \frac{k1}{ki}로 정의되는 각 기질의 메탄올 단위체 선택성(monomer selectivity)은 80% 메탄올 용액에서 최대이며, 그 크기 순위는 p-NO_2 > p-Cl > p-H > p-CH_3$로서 전이상태 구조가 tight할 수록 fi값이 크며 메탄올 단위체를 예민하게 선별 감지함을 알 수 있었다

Keywords

References

  1. J. Amer. Chem. Soc. v.92 W. A. Pryor;K. Smith
  2. J. Korean Chem. Soc. v.18 I. Lee;W. K. Kim
  3. J. Chem. Soc. no.B O. Rogne
  4. J. Korean Chem. Soc. v.24 H. W. Lee;S. La;I. Lee
  5. Handbook of Chemistry and Physics(59th Edition) Robert C. Weast(ed.)
  6. J. Korean Chem. Soc. v.22 I. Lee;W. K. Kim
  7. Phil. Mag. v.2 E. A. Guggenheim
  8. J. Chem. Soc. D. A. Brown;R. F. Hudson
  9. J. Korean Chem. v.23 I. Lee;K. B. Ryu;B. C. Lee
  10. The PMO theory of Org. Chem. M. J. S. Dewar;R. C. Dougherty
  11. Frontier Orbitals and Org. Chem. Reactions I. Fleming
  12. Topics in Curr. Chem. v.70 Structural Theory of Org. Chem. N. D. Epiotis;W. R. Cherry;S. Shaik;R. L. Yate;F. Bernardi
  13. Bull. Chem. Soc. Japan. v.42 K. Fukui;H. Fugimoto
  14. J. Chem. Phys. v.13 H. S. Frank;M. W. Evans
  15. J. C. S. Perkin II. R. W. Taft;M. J. Kamlet
  16. J. Amer. Chem. Soc. v.70 no.119 C. G. Swain;C. B. Scott
  17. J. Amer. Chem. Soc. v.73 C. G. Swain;C. B. Scott
  18. J. Amer. Chem. Soc. v.77 C. G. Swain;C. B. Scott
  19. J. C. S. Perkin II. Y. Karton;A. Pross