Department of Civil, Environmental, and Geodetic Engineering, The Ohio State University, Columbus, Ohio 43210, United States.
Department of Organismal Biology and Ecology, Colorado College, Colorado Springs, Colorado 80903, United States.
Environ Sci Technol. 2022 Apr 19;56(8):4728-4748. doi: 10.1021/acs.est.1c03621. Epub 2022 Mar 31.
Permanganate oxidation is an attractive environmental remediation strategy due to its low cost, ease of use, and wide range in reactivity. Here, permanganate reactivity trends are investigated for model organic compounds and organic contaminants. Second-order permanganate reaction rate constants were compiled for 215 compounds from 82 references (journal articles, conference proceedings, master's theses, and dissertations). Additionally, we validated some phenol rate constants and contribute a few additional phenol rate constants. Commonalities between contaminant oxidation products are also discussed, and we tentatively identify several model compound oxidation products. Aromatic rings, alcohols, and ether groups had low reaction rate constants with permanganate. Alkene reaction sites had the highest reaction rate constants, followed by phenols, anilines, and benzylic carbon-hydrogen bonds. Generally, permanganate reactivity follows electrophilic substitution trends at the reaction site where electron donating groups increase the rate of reaction, while electron withdrawing groups decrease the rate of reaction. Solution conditions, specifically, buffer type and concentration, may impact the rate of reaction, which could be due to either an ionic strength effect or the buffer ions acting as ligands. The impact of these solution conditions, unfortunately, precludes the development of a quantitative structure-activity relationship for permanganate reaction rate constants with the currently available data. We note that critical experimental details are often missing in the literature, which posed a challenge when comparing rate constants between studies. Future research directions on permanganate oxidation should seek to improve our understanding of buffer effects and to identify oxidation products for model compounds so that extrapolations can be made to more complex contaminant structures.
高锰酸盐氧化因其成本低、使用方便、反应活性范围广而成为一种有吸引力的环境修复策略。在这里，研究了模型有机化合物和有机污染物的高锰酸盐反应趋势。从 82 篇参考文献（期刊文章、会议记录、硕士论文和博士论文）中为 215 种化合物编译了二级高锰酸盐反应速率常数。此外，我们验证了一些苯酚的速率常数，并提供了一些额外的苯酚速率常数。还讨论了污染物氧化产物之间的共性，并暂定确定了几种模型化合物氧化产物。芳香环、醇和醚基与高锰酸盐的反应速率常数较低。烯烃反应位点具有最高的反应速率常数，其次是苯酚、苯胺和苄基碳氢键。一般来说，高锰酸盐的反应活性遵循反应位点的亲电取代趋势，其中供电子基团增加反应速率，而吸电子基团降低反应速率。溶液条件，特别是缓冲类型和浓度，可能会影响反应速率，这可能是由于离子强度效应或缓冲离子作为配体的作用。不幸的是，这些溶液条件的影响排除了用当前可用数据为高锰酸盐反应速率常数开发定量结构-活性关系的可能性。我们注意到，文献中经常缺少关键的实验细节，这在比较不同研究中的速率常数时带来了挑战。高锰酸盐氧化的未来研究方向应致力于提高我们对缓冲效应的理解，并确定模型化合物的氧化产物，以便可以将推断扩展到更复杂的污染物结构。
