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Journal of the Korean Chemical Society (JKCS)

ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 41, Number 4
JKCSEZ 41(4)
August 20, 1997 

Hydrolysis Mechanism of N-(2,4-dinitrophenyl)benzhydrazonyl Bromide Derivatives

N-(2,4-dinitrophenyl)benzhydrazonyl Bromide 유도체의 가수분해 반응메카니즘
Chan-Il Park, Ki-Won Cha, Ikchoon Lee, Byung-Du Chang

N-(2,4-dinitrophenyl)benzhydrazonyl bromide 유도체들의 가수분해 반응속도상수를 20℃의 수용액에서 자외선 분광광도법으로 측정하여 넓은 pH 범위에서의 반응속도식을 구하였다. 반응속도식, 용매효과, 치환기 효과, 염효과, 열역학적 활성화 파라미터 등이 결과로부터 가수분해 반응메카니즘을 제안하였다. 즉, pH 3.0에서는 carbonium ion 중간체를 거져 SN1 반응에 의해 진행되며, pH 10.0에서는 1,3-dipolar 반응 메카니즘 또는 SN2 반응에 의해 진행됨을 제안하였다.

The rate constants for the hydrolysis of N-(2,4-dinitrophenyl)benzhydrazonyl bromide and its derivatives were determined by ultraviolet visible spectrophotometry at 20℃ and a rate equation which could be applied over a wide pH range was obtained. On the basis of rate equations derived and judging from the solvent effect, substituent effect, salt effect, thermodynamic parameter, plausible mechanisms of hydrolysis have been proposed. It may be concluded that the hydrolysis through SN1 mechanism via carbonium ion intermdiate to pH 3.0, and pH 10.0, the hydrolysis proceeds through 1,3-dipolar or SN2 mechanism.

198 - 204
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