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Journal of the Korean Chemical Society (JKCS)

ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 13, Number 2
JKCSEZ 13(2)
April 20, 1969 

 
Title
Halogen Exchange Reactions of Benzyl Halides Part Ⅲ-Kinetics of Reactions of Bromide and Iodide Ions with Benzyl Chloride and Bromide in Absolute Acetone

벤질 할라이드의 할로겐 교환반응 (제Ⅲ보) 아세톤 중에서의 염화 및 브롬화 벤질과 브롬화 및 요오드화 이온간의 교환반응
Author
Myung-Hwan Whangbo, Bon-su Lee, Ikchoon Lee

황보명환, 이본수, 이익춘
Keywords
Abstract
할로겐화 벤질의 할로겐 교환반응을 무수 아세톤에서 연구하였으며 반응속도상수 계산에는 새로 유도한 적분식을 사용하였다. 아세톤 용매 속에서의 할로겐 이온들의 친핵반응성은 90% 에탄올 용매속에서의 것과 정반대 순서이며 이것은 HSAB 원리와 할로겐 이온의 solvation으로 설명할 수 있었다. 아세톤 용매 속에서의 반응속도의 증가는 △H≠의 감소보다는 △S≠의 증가에 기인되며 또 전이상태의 solvation 현상도 그 원이이 될 수 있음을 논의하였다.

Halogen exchange reactions of benzyl halides have been studied in absolute acetone. Rate constants were calculated using an integrated rate expression derived for the reaction involving ion-pair association. The order of nucleophilicity of halide ions in acetone was found to be a reverse of the order in 90% aqueous enthanol solvent. This was interpreted by means of HSAB principle and solvation of halide ions. Net increase in rate of reaction in acetone compared with the rate in protic solvent resulted from large increase in ΔS≠ rather than decrease in ΔH≠. The solvation of the transition state also contribute to the net increase in rate.

Page
109 - 114
Full Text
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