The formation and decomposition kinetics of N-chloro-N-methyl amino acids were studied to predict the fate and impact of these compounds in water treatment technologies and biological systems. These compounds form in fast second-order reactions between N-methyl amino acids and hypochlorous acid. The comparison of the activation parameters for the reactions of N-methyl substituted and nonsubstituted branched-chain amino acids reveals the transition-state features less organized structure and stronger bonds between the reactants in the reactions with the N-methyl derivatives. This is due to a combined positive inductive effect of the N-methyl group and the alkyl side chain as well as to the steric effects of the substituents. N-Methyl-N-chloro amino acids decompose much faster than the nonsubstituted compounds. The reaction rates do not depend on the pH, and the same final product is formed in the entire pH range. N-Chlorosarcosine is an exception, as it decomposes via competing paths, k_d^obs = k_d + k_d^OH[OH^–], yielding different final products. This feature is most likely due to the lack of an alkyl substituent on the α-carbon atom. Under physiological pH, aldehydes and methylamine form in these reactions, which are not particularly toxic.

中文翻译：

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N-甲基氨基酸与次氯酸的氯化：动力学和机制。

研究了N-氯-N-甲基氨基酸的形成和分解动力学，以预测这些化合物在水处理技术和生物系统中的归宿和影响。这些化合物在N-甲基氨基酸和次氯酸之间的快速二级反应中形成。N-甲基取代和未取代的支链氨基酸反应活化参数的比较揭示了过渡态的特点是在与N-甲基衍生物的反应中反应物之间的组织结构较少且键合较强。这是由于N-甲基和烷基侧链以及取代基的空间效应。N-甲基-N-氯氨基酸比未取代的化合物分解得快得多。反应速率不取决于 pH 值，并且在整个 pH 值范围内形成相同的最终产物。N-氯肌氨酸是个例外，因为它通过竞争路径分解，k _d ^obs = k _d + k _d ^OH [OH ^–]，产生不同的最终产品。这种特征很可能是由于 α-碳原子上缺少烷基取代基。在生理 pH 值下，这些反应中会形成醛和甲胺，它们没有特别的毒性。