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Journal of the Korean Chemical Society (JKCS)

ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 44, Number 2
JKCSEZ 44(2)
April 20, 2000 

Kinetic Studies on the Mechanism of Hydrolysis of 2-Phenyl-4H, 5H-3-methyl-3-thiazolinium Perchlorate Derivatives

2-Phenyl-4H, 5H-3-methyl-3-thiazolinium Perchlorate 유도체의 가수분해 반응 메카니즘에 관한 반응속도론적 연구
Tae Rin Kim, So Young Lee, Man So Han, Sang Yong Pyun, Seok Hee Lee

김태린, 이소영, 한만소, 변상용, 이석희
2-PhenyI-4H,5H-3-methyl-3-thiazolinium perchlorate(PTP)유도체들의 가수분해속도상수를 수용액에서 자외선 분광법으로 측정하여 넓은 pH 범위에서 적용될 수 있는 속도식을 구하였다. pH에 따른 속도상수의 변화, 가수분해 생성물의 확인, 일반염기 및 치환기 효과 둥을 바탕으로 반응 메카니즘을 제안하였다, 즉 pH 4.0 이하에서는 물분자의 첨가가 일어나 가수분해가 진행되며, pH 9.0 이상에서는 전형적인 Michael type의 반응이 일어나며, pH 4.5~8.0 사이에서는 이들 두 반응이 경쟁적으로 일어남을 알았다.

The rate constants for the hydrolysis of 2-phenyl-4H,5H-3-methyl-3-thiazolinium perchlorate(PTP) derivatives were detemined by the use of ultraviolet visible spectrophotometer in water. The rate equations which could be applied over a wide pH ranges were obtained.On the basis of rate equation,hydrolysis product analysis, general base catalysis, and substituent effect, a plausible mechanism of the hydrolysis is proposed: Below pH 4.0, the reaction is initiated by addition of water, while above pH 9.0,Michael type nucleophilic addition t

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