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Journal of the Korean Chemical Society (JKCS)

ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 22, Number 1
JKCSEZ 22(1)
February 20, 1978

Title	Kinetic Studies on the Mechanism of Hydrolysis of α-Nitrobenzaldehydephenylhydrazone α-Nitrobenzaldehydephenylhydrazone의 가수분해에 대한 반응속도론적 연구
Author	Tae-Rin Kim, Won-Sil Choi 김태린, 최원식
Keywords
Abstract	25% dioxane 수용액 속에서 α-nitrobenzaldehydephenylhydrazone의 여러 유도체(p-NO2, m-NO2, p-Cl, p-CH3)에 대해 pH의 변화에 따르는 가수분해 속도상수를 25℃에서 자외선 분광광도법으로 측정하여 넓은 pH에서 잘 맞는 반응 속도식을 구하였다. 가수분해 속도에 미치는 치환기효과를 고려하고자 Hammett의 식을 적용한 결과 pH1.0에서는 ρ=0.18, pH 7.0에서는 ρ=0.06을 얻었다. pH의 변화에 따르는 반응속도상수의 변화, 용매효과, 치환기효과, 산해리상수 측정 등으로부터 α-nitrobenzaldehydephenylhydrazone의 가수분해는 pH 3.0 이하에서는 Sn1, pH 4.0 이상에서는 1,3-dipole을 거치는 반응이 pH 3.0 과 pH 4.0 사이에서는 이 두 반응이 경쟁적으로 일어남을 알았다. The kinetics of hydrolysis of α-nitrobenzaldehydephenylhydrazone derivatives (p-NO2, m-NO2, p-Cl, p-CH3) have been investigated by UV spectrometry in 25% dioxane-water at 25℃ and a rate equation which can be applied over wide pH range was obtained. From the rate equation and the effect of solvent, substituent and pKa on the rate equation, the following reaction mechanisms were proposed. Below pH 3.0 the hydrolysis of α-nitrobenzaldehydephenylhydrazone proceeds by SN1 mechanism, while above pH 4.0 the hydrolysis proceeds through 1,3-dipole ion mechanism. In the range of pH from 3.0 to 4.0 these two reactions occur competitively.
Page	30 - 36
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