【摘要】 利用脉冲辐解技术对 2-氯酚水溶液在多种条件下的降解行为进行了详细研究。对瞬态光谱中的主要吸收作了归属,并考察了这些瞬态产物的生成和衰减动力学。研究表明,在不同 pH 值下,2-氯酚与?OH 的反应途径不同:中性条件下主要生成羟基加成物,其生成速率常数为 8.3×109dm3?mol-1?s-1;碱性条件下,则主要发生电子转移形成 2-氯代酚氧基,同时存在羟基加成物脱 HCl 和脱 OH-过程。?N3与 2-氯酚发生单电子氧化,形成 2-氯代酚氧基。?H 与 2-氯酚发生加成反应生成环己二烯类氢加成物,其速率常数为 2.5×109dm3 ? mol-1 ? s-1。eaq 与 2-氯酚发生电子转移,生成羟苯基和氯离子,碱性条件(pH=11)和中性条件下的速率 -常数分别为 3.5×108 dm3?mol-1?s-1和 2.2×109 dm3?mol-1?s-1。该结果有助于人们进一步了解氯酚降解的本质,从而为该类化合物的降解处理提供了理论基础。更多还原

【Abstract】 The kinetics and mechanisms of the reactions of 2-chlorophenol with hydroxyl radical, azide radical, hydrogen atom and hydrated electron have been studied using pulse radiolysis. In neutral solutions, relatively stable hexadienyl type OH-adducts is formed upon the addition of hydroxyl radical to the aryl ring of the substrate. In alka- line solutions, 2-chlorophenoxyl radical and semi-quinone radical anion are formed through the electron transfer from the substrate to hydroxyl radical as well as OH-addition followed by HCl/OH- elimination. Azide radical oxidizes 2-chlorophenol via one-electron transfer, forming correspondent o-chloro-phenoxyl radical. Hydrogen atom reacts with the substrate via the addition to the aryl ring, forming hexadienyl type ?H-adducts. Under the attack of hydrated electron, 2-chlorophenol undergoes reductive Cl- elimination, with the rate constant of 3.5×108 dm3?mol-1?s-1in alka- line solution and 2.2×109dm3?mol-1?s-1in neutral solution respectively. These results shed light on the degradation mechanism of chlorophenols and provide theoretical foundation for treatments of wastewater contaminated with chlorophenols.更多还原