Permanganate Oxidation of Organic Contaminants and Model Compounds

Abstract

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.

Roles of MnO2 Colloids and Mn(III) during the Oxidation of Organic Contaminants by Permanganate

“…Permanganate (MnO 4 – , Mn­(VII)) has been applied to water pollution control over decades due to its multiple environmentally benign characteristics, such as ease of handling, effectiveness over a wide pH range, and relatively low cost. , Mn­(VII) is a selective chemical oxidant preferentially reacting with electrophilic organics (e.g., phenols, anilines, olefins, and thiols) under environmentally relevant conditions. ,, Different from reactive radical species (e.g., HO • and SO 4 •‑ ), Mn­(VII) is less susceptible to coexisting water matrix constituents . Moreover, in situ generated MnO 2 colloids can not only serve as a coagulant/adsorbent to aid the removal of contaminants , but also catalyze the Mn­(VII) oxidation of organic contaminants. , The unique features make Mn­(VII) advantageous over commonly used water treatment oxidants for removal of emerging organic contaminants .…”

“…3,4 Mn(VII) is a selective chemical oxidant preferentially reacting with electrophilic organics (e.g., phenols, anilines, olefins, and thiols) under environmentally relevant conditions. 2,3,5 Different from reactive radical species (e.g., HO • and SO 4…”

Production of Dichloroacetonitrile from Derivatives of Isoxaflutole Herbicide during Water Treatment

“…Due to the high yield of DCAN from the reaction of diketonitrile with both free chlorine and chloramine, we investigated the reaction of diketonitrile with permanganate, which is used as a preoxidant in water treatment to prevent DBP formation. , Diketonitrile minimally reacted with permanganate (e.g., diketonitrile concentrations decreased by <3% in the presence of excess permanganate over 92 h, SI section 4.6), consistent with permanganate only reacting with certain drinking water contaminants. − Diketonitrile does not contain moieties susceptible to reaction with permanganate such as olefins, − aliphatic amines, tertiary aromatic amines, and thioethers . The lack of reaction between diketonitrile and permanganate indicates that preoxidation by permanganate is unlikely to remove diketonitrile as a DCAN precursor in drinking water.…”

Evaluation of sequential dosing of potassium permanganate for microcystin‐LR removal

“…Recent work suggests that permanganate preferentially reacts with aromatic moieties in DOM to form quinones, benzoic acids, and carboxylic acid ring-opening products; a portion of products are nitrogen-containing compounds (Laszakovits et al, 2020). A review of permanganate reaction rate constants suggests that phenols are one such likely reaction site and that electron-donating moieties, such as amines, can increase the rate of reaction between the organic compound and permanganate (Laszakovits et al, 2022). These observations indicate that the DOM components in raw water exhibit a range in bimolecular rate constants for reaction with permanganate.…”