Amides are common constituents in natural organic matter and synthetic chemicals. In this study, we investigated kinetics and mechanisms of the reactions of chlorine with seven amides, including acetamide, N-methylformamide, N-methylacetamide, benzamide, N-methylbenzamide, N-propylbenzamide, and N-(benzoylglycyl)glycine amide. Apparent second-order rate constants for the reactions of the amides with chlorine at pH 8 are in the range of 5.8 × 10⁻³ – 1.8 M⁻¹s⁻¹ and activation energies in the range of 62-88 kJ/mol. The second-order rate constants for the reactions of chlorine with different amides decrease with increasing electron donor character of the substituents on the amide-N and N-carbonyl-C in the amide structures. Hypochlorite (^‒OCl) dominates the reactions of chlorine with amides yielding N-chloramides with species-specific second-order rate constants in the range of 7.3 × 10⁻³ – 2.3 M⁻¹s⁻¹. Kinetic model simulations suggest that N-chlorinated primary amides further react with HOCl with second-order rate constants in the order of 10 M⁻¹s⁻¹. The chlorination products of amides, N-chloramides are reactive towards phenolic compounds, forming chlorinated phenols via electrophilic aromatic substitution (phenol and resorcinol) and quinone via electron transfer (hydroquinone). Meanwhile, N-chloramides were recycled to the parent amides. At neutral pH, apparent second-order rate constants for the reactions between phenols and N-chloramides are in the order of 10⁻⁴-0.1 M⁻¹s⁻¹, comparable to those with chloramine. The findings of this study improve the understanding of the fate of amides and chlorine during chlorination processes.

酰胺是天然有机物和合成化学品中的常见成分。在这项研究中，我们研究了氯与七种酰胺的反应动力学和机理，包括乙酰胺、N-甲基甲酰胺、N-甲基乙酰胺、苯甲酰胺、N-甲基苯甲酰胺、N-丙基苯甲酰胺和N- (苯甲酰甘氨酰)甘氨酰胺。在pH 8 下，酰胺与氯的反应的表观二阶速率常数在5.8 × 10 -3 ^– 1.8 M ^-1 s ^-1范围内，活化能在62-88 kJ/mol 范围内。氯与不同酰胺反应的二级速率常数随着酰胺结构中酰胺-N和N-羰基-C上取代基的电子给体特征的增加而降低。次氯酸盐 ( ^-OCl ) 在氯与酰胺的反应中占主导地位，生成N -氯酰胺，其物种特异性二阶速率常数在 7.3 × 10 ^-3 – 2.3 M ^-1 s ^-1范围内。动力学模型模拟表明N-氯化伯酰胺进一步与HOCl反应，二级速率常数约为10 M ^-1 s ^-1。酰胺、N-氯酰胺的氯化产物对酚类化合物具有反应性，通过亲电芳香取代（苯酚和间苯二酚）形成氯化酚，通过电子转移形成醌（氢醌）。同时，N-氯酰胺被回收为母体酰胺。在中性pH下，苯酚和N-氯酰胺之间的反应的表观二阶速率常数约为10 ^-4 -0.1 M ^-1 s ^-1，与氯胺的反应相当。这项研究的结果提高了人们对氯化过程中酰胺和氯的命运的了解。