Phenylureas. Part 2.1 Mechanism of the acid hydrolysis of phenylureas
作者:Robert Laudien、Rolf Mitzner
DOI:10.1039/b008535i
日期:2001.11.1
The mechanism of the hydrolytic decomposition of phenylureas in acid media is investigated. It includes, in part, knowledge already present in the literature. Over the investigated pH range the occurrence of a rate maximum in the pH curves due to the strongly reduced water activity at higher acid strengths is observed. An addition–elimination mechanism with rate-determining attack of water at the N-protonated substrate is proposed. The reversion of the substituent influence on the reaction rate with increasing acidity of the reaction medium points to a change of the hydrolytic decomposition mechanism in strongly acidic media.
研究了在酸性介质中苯基脲的水解分解机制。这部分包括已有文献中的知识。在所研究的pH范围内,观察到由于在较强酸度下水活性显著降低,pH曲线中出现了反应速率的最大值。提出了一种加成-消除机制,其中水对N质子化底物的攻击为速率决定步骤。随着反应介质酸度的增加,取代基对反应速率影响的反转表明在强酸性介质中水解分解机制发生了变化。