Kinetic Study on the Alkaline Hydrolysis of the 4-Substituted Phenyl Ethyl Benzylphosphonates

4-치환 Phenyl Ethyl Benzylphosphonate의 알칼리 가수분해 반응에 대한 속도론적 연구

  • Shon, Kyoung Hwa (Department of Chemistry, Gyeongsang National University) ;
  • Park, Kyung Kone (Department of Chemistry, Gyeongsang National University) ;
  • Lee, Bu Young (Department of Chemistry, Gyeongsang National University) ;
  • Shin, Bu Young (Department of Chemistry, Gyeongsang National University)
  • 손경화 (경상대학교 자연과학대학 화학과) ;
  • 박경곤 (경상대학교 자연과학대학 화학과) ;
  • 이부영 (경상대학교 자연과학대학 화학과) ;
  • 신갑철 (경상대학교 자연과학대학 화학과)
  • Published : 19970600

Abstract

The rate constants($k_{OH}$) for the alkaline hydrolysis of the 4-substituted phenyl ethyl benzylphosphonates were determined in various buffer solutions by UV(Vis spectrophotometer. The activation entropies of the title reactions show negative values and this result is not consistent with a dissociative mechanism (EA) for which a positive or slightly negative value of the entropy of activation should be expected. An associative mechanism(AE) is favorable because the negligible negative charge is generated on the leaving group in the rate determining step from a good Hammett relationship(ρ=1.89). By the results of a kinetic study, we conclude that a dissociative mechanism is not proceeded in the title reactions.

Keywords

References

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