| pH对高锰酸钾氧化降解苯胺类化合物动力学的影响 |
| 摘要点击 2145 全文点击 1187 投稿时间：2015-08-14 修订日期：2015-09-19 |
| 查看HTML全文
查看全文 查看/发表评论 下载PDF阅读器 |
| 中文关键词 高锰酸钾 苯胺类化合物 自催化 类抛物线现象 质子传递模型 |
| 英文关键词 permanganate anilines auto-catalysis parabola-like shaped pH-rate profile proton transfer model |
|
| 中文摘要 |
| 以苯胺和对氯苯胺为目标污染物,在假一级动力学实验条件下(KMnO4初始浓度是目标有机物初始浓度的10倍),考察了pH对KMnO4氧化降解苯胺类化合物的动力学的影响. 发现在KMnO4氧化降解苯胺类化合物的过程中存在明显的自催化现象,推测这种自催化现象可能是由于原位生成的MnOx在其表面络合目标污染物,从而促进了KMnO4对污染物的氧化速率. 对不同pH条件下KMnO4氧化苯胺类化合物的动力学数据进行了假一级拟合获得假一级反应速率常数(kobs),通过KMnO4浓度与kobs进一步得到的二级反应速率常数k" (M-1·s-1)随pH的增加先升高后降低,在苯胺和对氯苯胺各自的pKa附近时达到最大,即文献中提出的类抛物线现象. 笔者之前提出的质子传递模型可以很好地拟合KMnO4氧化苯胺和对氯苯胺的二级反应速率常数随pH的变化趋势. |
| 英文摘要 |
| To investigate the effect of pH on the oxidation of anilines by potassium permanganate, aniline and p-Chloroaniline were taken as the target contaminants, and the experiments were conducted under the condition with potassium permanganate in excess over a wide pH range. The reaction displayed remarkable autocatalysis, which was presumably ascribed to the formation of complexes by the in situ generated MnOx and the target contaminants on its surface, and thereby improved the oxidation rate of the target contaminants by permanganate. The reaction kinetics was fitted with the pseudo-first-order kinetics at different pH to obtain the pseudo-first-order reaction constants (kobs). The second-order rate constants calculated from permanganate concentration and kobs increased with the increase of pH and reached the maximum near their respective pKa, after which they decreased gradually. This tendency is called parabola-like shaped pH-rate profile. The second-order rate constants between permanganate and anilines were well fitted by the proton transfer model proposed by us in previous work. |
|
|
|
